Web searching - School of Communication and Information
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Transcript Web searching - School of Communication and Information
Web searching &
the invisible web
Finding things that are hard
to find
© Tefko Saracevic
Principles of Searching
1
Dictionary definitions
World wide web :
Internet-connected files
the very large set of linked documents and other files
located on computers connected through the Internet
and used to access, manipulate, and download data
and programs
Invisible - dictionary definition:
not easily noticed; not noticed or detected readily
Invisible web – not yet in the dictionary
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What is “Invisible web?”
Materials that general search engines cannot or
WILL not include in their collection of web pages
(indexes)
You cannot find through general search engines
Contains a vast amount of information resources
much of it authoritative & higher quality than visible web
quality becomes a main issue
much of it specialized
a lot of it also fluid or streaming or real time
“You can’t step in the same river twice”
much of it free
Many times larger than the visible Web
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in other words…
There is much more to the web than
or
Distribution of use:
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Why search engines do not
cover all?
Size: web is huge, cannot cover all
Economics: associated costs are high
Technical: still a challenge & limited capabilities
engines support themselves mostly by ads
also a number of engines have rank per pay & crawl
update per pay - providing paid listings first & mostly
also some file formats hard to cover
Spam: eliminating bad also looses good
Restrictions: some site do not let in
Deep structure: some sites complex
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How do search engines
work? Main parts
Crawlers, spiders: go out to find content
looking for new & changed sites
periodic, not for each query
no search engine works in real time
Organizing content: labeling, arranging
indexing for searching or classifying as directory
Databases, caches: storing content
Retrieval engine: searching on basis of query
Interface: handles query, displays results
All based on various, mostly proprietary algorithms
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Search engine coverage
No engine covers more than a fraction of WWW
Hard (impossible) to discern & compare coverage
Many national search engines
own coverage, orientation, governance
Many topical or domain search engines
estimates: none more than 16%
own coverage geared to subject of interest
Many comprehensive sources independent of
search engines
some compilations of evaluated web sources
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Search engines differ
Substantial differences among search
engines on each of these parts
Need to know how they work & differ
Information about search engines:
Search Engine Watch
ratings, news, statistics, charts, explanations, tutorials
Search Engine Showdown
© Tefko Saracevic
“The users’ guide to web searching” - run by a librarian,
news links, ratings
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Invisible web searching:
Basic approach
The first step in determining the best approach
for searching the invisible web is to have a clear
idea of what you’re seeking
extensive user modeling
Limit your search to appropriate resources &
tools for the particular type of information you’re
looking for
know your sources
know how to find appropriate sources
shades of “Knowledge is of two kinds…”
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Specialized sources -
particularly for the invisible web
The rest of the lecture covers:
1.
2.
3.
4.
5.
6.
7.
8.
9.
© Tefko Saracevic
Meta search engines
Specialized engines & catalogs
Domain (subject) engines & catalogs
Reference sources
Libraries as web sources
Virtual libraries
Subject databases
Societies, organizations
Good old books
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Meta search engines
Meta search engines search multiple engines
getting combined results from a variety of engines
Finding a search engine or meta engine:
SearchEngines.com
search for engines by topic, geography, reference
Search Engine Guide
engines categorized by topic; other engine information
Search Engine Colossus
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international directory of search engines by country, topic from
198 countries and 61 territories; engines in choice of languages
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Sample of meta engines
Some meta engines provide organized results:
Dogpile
results from a number of leading search engines; gives
source, so overlap can be compared; (has also a (bad) joke
of the day)
Surfwax
gives statistics and text sources & linking to sources; for some
terms gives related terms to focus
Teoma
results with suggestions for narrowing; links resources
derived; originated at Rutgers
Turbo10
provides results in clusters; engines searched can be edited
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meta search engines (cont.)
Large directory
Complete Planet
directory of over 70,000 databases & specialty engines
Results with graphical displays
Vivisimo
clusters results; innovative
Webbrain
results in tree structure – fun to use
Kartoo
results in display by topics of query
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Domain engines &
catalogs
Cover general & specific subjects
Open Directory Project
BUBL LINK
large edited catalog of the web – global, run by volunteers
selected Internet resources covering all academic subject
areas; organized by Dewey Decimal System – from UK
Profusion
search in categories for resources & search engines
Resource Discovery Network – UK
“UK's free national gateway to Internet resources for the
learning, teaching and research community”
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domain engines …
Available in variety of domains & subjects – rich!
Think Quest – Oracle Education Foundation
All Music Guide
education resources, programs; web sites created by students
resource about musicians, albums, and songs
Internet Movie Database
treasure trove of American and British movies
Genealogy links and surname search engines
well.. that is getting really specialized (and popular)
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domain engines …
Scholarship, science
Psychcrawler - Amer Psychological Association
web index for psychology
Entrez PubMed – Nat Library of Medicine
biomedical literature from MEDLINE & health journals
CiteSeer - NEC Research Center
scientific literature, citations index; strong in computer science
Scholar Google
searches for scholarly articles & resources
Infomine
scholarly internet research collections
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Reference services
Reference services - several models
Ask Jeeves!
most popular, commercial
Information Please
almanac type questions
RefDesk
access to a number of reference tools
Wikipedia
web encyclopedia in many languages
Martindale’s The reference Desk
probably the most amazing & versatile reference collection on
the web – numerous sections, great to explore
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reference …
•
Digital reference - new service area for libraries
QuestionPoint L of Congress & OCLC
Virtual Reference Desk – L of Congress
project for a global reference network
large compilation of web reference sites
LiveRef - maintained at Iowa State U
a registry of real time digital reference services
Martindale’s The reference Desk
probably the most amazing & versatile reference
collection on the web – numerous sections,
great to explore
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Libraries as web sources
Academic, national libraries providing open
collections & services; models vary
Rutgers libraries - big long term effort
University of California, Berkeley
a most elaborate effort together with Sun Corporation
LibWeb U California, Berkeley
“lists currently over 7200pages from libraries in over 125
countries”
Bibliothèque Nationale de France
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includes virtual exhibitions, among others
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Virtual libraries on the Web
Libraries emerging only on the Web
Virtual Library –
Internet Public Library U of Michigan
Switzerland, US, UK & other countries – ‘oldest virtual library on
the Web’
also a long term effort
Librarians Index of the Internet
very popular and comprehensive
Digital librarian
“a librarian's choice of the best of the Web “ – compiled and
annotated by a librarian
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virtual libraries …
Academic Info Digital Library
Gabriel
many links to digital collections & resources in various subjects
Gateway to European National Libraries
Museum of online museums
a delight
Stanford Encyclopedia of Philosophy
a comprehensive encyclopedia and library
The historical New York Times Project
universal library – ongoing digitization
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Subjects resources
Many subject specific sites
rich & often unique coverage & services
different approaches & requirements
Examples in health related domains:
WebMDHealth
Rxlist
news, medical information
The Internet Drug Index
Mayo Clinic HealthOasis
health advice
Kidshealth
sites for parents, kids, teens
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Subject resources …
Scholarship, humanities, government
KIRKE - Katalog der Internetressourcen für die
Klassische Philologie aus Erlangen
German; a variety of resources for classics
Perseus Digital Library Tufts University
covers antiquity to renaissance; one of the best subject
sites on the web; affected the whole field
Sch of Slavonic & East European Studies,
University College London
includes country resources, e.g. Croatia
U Mich Document Center
official documents from all over the world
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Subject resources …
Growing number of resources in arts, museums
MuseumStuff.com
“We have 1000's of museums, zoos, historical
societies and related organizations in our
database”
The State Hermitage Museum
One of the greatest museums in the world, and one
of the best museum site – developed with IBM
help
National Museum of Science and Technology
Leonardo da Vinci
Guess where those pictures came from. A delight!
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subject resources …
Diotima
Materials for study of women and gender in the Ancient World
Moving Images Collections
“MIC documents moving image collections around the world.”
Part particularly oriented toward science educators. Now at
Library of Congress, but developed at Rutgers.
And, of course …
Snoopy
The Official Peanuts Website
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Societies, organizations
Many societies, agencies developed their sites
great many rich sources for searching & resources
differences in requirements, depth, richness
Assoc. for Computing Machinery
Digital Library; subscription or registration or through RUL
US State Department
about the U.S & other countries
FirstGov
the US government official web portal
Ocean Planet NASA
presentation of earth & its vast oceans
ArXiv Cornell U, National Science Foundation
e-print service in the fields of physics, mathematics, nonlinear science, computer science, and quantitative biology
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Archiving, books on the web
Internet Archive – a large undertaking
includes web archive & lots more publicly available & free
10 billion web pages archived from 1996 to a few months ago
Wayback Machine – search to look at old versions of web
pages
Books on the web
Million Book Project
digitizing books and providing free access
International Children’s Digital Library
online children books
Digital books Index
“links to more than 105,000 title records from more than 1800
commercial and non-commercial publishers, universities, and
various private sites”
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Language barriers on
the Web
English still the major language
but declining, now slightly over 50%
Multilingual retrieval search engines
Euroseek
searches in a number of languages
All the Web
results in 45 languages
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Web news; keeping up
What is going on on the Web? Some major
sources of news and evaluations:
Free Pint
newsletter, articles, links; nice & sometimes quirky
Internet Resources Newsletter
UK based; monthly newsletter for “academics, students,
engineers, scientists and social scientists”
ResearchBuzz
daily updates; many aspects; “Collection of items on search
engines, online databases, and other information resources”
About.com Web Search
tools, Web Search Forum
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keeping up …
Information Today
trade & professional monthly newspaper & web site; industry
news; searcher columns; general analyses of trends
Keeping up through blogosphere:
Resource Shelf
bloger about internet (and some other stuff) with archive; it
has really good and really bad exchanges & threads
New York Times blogrunner - The annotated NYT
blog tracking of NYT articles, topics, authors; thread into
discussion of many other weblogs; includes net & web
topics
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Finding links & listings –
back to good old books with a new twist
Number of books on web searching have also
sites with links in the book, updates, news
Extreme Searcher Randolph Hock
update of a popular book; links by chapter topics
The web library Nicholas G. Tomaiuolo
spotlights free resources, links by chapter and new topics –
done by a librarian
The invisible web Chris Sherman & Gary Price
original book on the topic, links organized by subject
p.s. most, but not all, of the sites in this lecture can
be found on those sites – and much, much more
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Evaluations, ratings
Evaluating web sites: a prime responsibility of
searchers & all information professionals
Many sources evaluate web sites:
The Scout Report –
Medical Library Association
librarians’ BIBLE! Annotations. Comprehensive.
ten most useful sites for consumer health
MLA user guide
for finding & evaluating health information on the web
Web 100
commercial, user ranking & evaluation of web sites
Evaluating web pages UC Berkeley
tutorial and guide
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Needed for Web searching
Knowledge & competencies on
variety of web sources & their organization
search engines
web search strategies
search dynamics, feedback
Keeping up & up & up
Why? many reasons, such as:
constant updates, changes, innovations
many domain/subject specific
fluidity very high
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Needed for web searching
by professionals
Knowledge of SOURCES in area of interest
search engines not enough
not too helpful in finding these other sources; structure
hard to discern
find & use specialized sources
Evaluation of sources
a key professional skill!
application of standard criteria & web criteria:
authority; accuracy; currency (timeliness);
objectivity; coverage, persistence, usability
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Needed competencies …
Knowledge of users & use
Knowledge of searching
Use of technology
Adaptability, flexibility
Integration with other resources
Teaching others
Constant learning & update
again: keeping up, keeping up, keeping up
and again: keeping up, keeping up, keeping up
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But now really: How to do it?
information
WWW
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Images
from the invisible web
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images …
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images …
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and of course…
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P.S. a nice site
Poem by Emily Dickinson, 1830-1886
In a library
Who will write a poem:
In a digital library
??????
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P.S. a few weird or fun sites…
SelectSmart.com
James Dean official web site
Deaducated
Dead Librarians’ Society
Livejournal
all kinds of quizzes for you
blogs & authoring tools; and many pathetic entries
Airline meals
“the world’s first and leading site about nothing but
airline food” … some 12,000 pictures from 447 airlines
it is not weird, but for real and great fun
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Sources
About.com Web Search http://websearch.about.com
Academic Info Digital Library http://www.academicinfo.net/digital.html
Airline meals http://www.airlinemeals.net/
All the Web http://www.alltheweb.com/
Ask Jeeves! http://www.ask.com/
Assoc. for Computing Machinery http://www.acm.org/
Bibliothèque Nationale de France http://www.bnf.fr/
BUBL LINK http://bubl.ac.uk/link/
CDNET Search.com http://www.search.com/
CiteSeer http://citeseer.nj.nec.com/
CompletePlanet http://completeplanet.com
Deaducated http://www.geocities.com/deadlibrarians/
Digital book index http://www.digitalbookindex.org/about.htm
Digital librarian http://www.digital-librarian.com/
Diotima http://turbo10.com/
Dogpile http://www.dogpile.com/
Entrez PubMed http://www.ncbi.nlm.nih.gov/PubMed/
Extreme Searcher http://www.extremesearcher.com/
Free Pint http://www.freepint.com/
Gabriel http://www.kb.nl/gabriel/
Genealogy http://darcisplace.com/darci/search.htm
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sources …
Hermitage http://www.hermitagemuseum.org/html_En/index.html
Information Please http://www.infoplease.com/
International Children’s Digital Library http://www.icdlbooks.org/
Internet Archive http://www.archive.org/
Internet Public Library, Michigan http://www.ipl.org/
Internet Resources Newsletter. http://www.hw.ac.uk/libwww/irn/
James Dean http://www.jamesdean.com/
Kartoo http://www.kartoo.com/
KIRKE http://www.phil.uni-erlangen.de/~p2latein/ressourc/ressourc.html
Leonardo da Vinci Museum http://www.museoscienza.org/english/
Librarians Index to the Internet http://lii.org/
Live Journal http://www.livejournal.com/
LiveRef http://www.public.iastate.edu/~CYBERSTACKS/LiveRef.htm
Martindale’s The reference Desk http://www.martindalecenter.com/
Mayo Clinic http://www.mayohealth.org/
Medical Library Assoc. ten top sites http://www.mlanet.org/resources/medspeak/topten.html
Medical Library Assoc. user guide for health inf.
http://www.mlanet.org/resources/userguide.html
Medscape http://www.medscape.com/
© Tefko Saracevic
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sources …
Million Book Project http://www.archive.org/texts/collection.php?collection=millionbooks
Museum of online museums. http://www.coudal.com/moom.php
MuseumStuff http://www.museumstuff.com/
NYT blogrunner http://nytimes.blogrunner.com/
NYT historical project http://www.nyt.ulib.org/
OCLC Web Characterization Project http://wcp.oclc.org/
Open Directory Project http://dmoz.org
Perseus Digital Library http://www.perseus.tufts.edu/
Profusion http://www.profusion.com/
Psychcrawler http://www.psychcrawler.com/
QuestionPoint http://www.questionpoint.org/
ResearchBuzz. http://www.researchbuzz.com/index.shtml
Resource Shelf http://resourceshelf.blogspot.com/
Rutgers Libraries http://www.libraries.rutgers.edu/
RxList http://www.rxlist.com/
Sch of East Eur & Slavonic Studies http://www.ssees.ac.uk/dirctory.htm
Search Engine Colossus http://www.searchenginecolossus.com/
Search Engine Guide http://www.searchengineguide.com/
Search Engine Showdown http://searchengineshowdown.com/
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sources …
Search Engine Watch http://searchenginewatch.com/
Select Smart.com http://www.selectsmart.com/home.html
Snoopy http://www.snoopy.com/
Stanford Encyclopedia of Philosophy http://www.wikipedia.org/
Surfwax http://www.surfwax.com/
Teoma http://teoma.com/
The invisible Web http://www.invisible-web.net/
The Scout Report. http://scout.cs.wisc.edu/
The Web Library http://www.ccsu.edu/library/tomaiuolon/theweblibrary.htm
Think Quest http://www.thinkquest.org/
Turbo10 http://turbo10.com/
U California Berkeley http://sunsite.berkeley.edu/
U Mich Documents Center http://www.lib.umich.edu/govdocs/
US State department http://www.state.gov/
Virtual Library http://vlib.org
Virtual Reference Desk http://www.loc.gov/rr/askalib/virtualref.html
Vivisimo http://vivisimo.com
Web 100 http://www.web100.com
Webbrain http://www.webbrain.com/html/default_win.html
WebMD http://my.webmd.com/webmd_today/home/default
Wikipedia http://www.wikipedia.org/
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