Transcript The Semantic Web Nottingham University 23 March 2007 © 2007 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.

The Semantic Web
Nottingham University
23 March 2007
© 2007 Hewlett-Packard Development Company, L.P.
The information contained herein is subject to change without notice
The Official Definition
Definition: The Semantic Web is the representation
of data on the World Wide Web. It is a collaborative
effort led by W3C with participation from a large
number of researchers and industrial partners. It is
based on the Resource Description Framework
(RDF), which integrates a variety of applications
using XML for syntax and URIs for naming.
http://www.w3.org/2001/sw/
11/6/2015
Slide 2 of 35
Semantic Web
11/6/2015
Slide 3 of 35
Semantic
11/6/2015
Slide 4 of 35
Semantic
=
Meaning ?
11/6/2015
Slide 5 of 35
The Semantic Web
 HTML for presentation
 XML for data
 RDF for meaning
Description
A new form of Web content that is
meaningful to computers will unleash a
revolution of new possibilities…
11/6/2015
Slide 6 of 35
or…
11/6/2015
Slide 7 of 35
Semantic
=
Data Modelling
11/6/2015
Slide 8 of 35
Semantic Web is about data
modelling
• To
make computers useful they must interact with the
real world
• So
they must model the real world in some way
• UML/Object
• Relational
schema
•
Oriented; classes, instances, attributes
(databases); tables, keys, constraints,
XML; documents, semistructured information,
schema
• Semantic
Web uses RDF – with some similarities
(and some differences) to these other techniques
11/6/2015
Slide 9 of 35
Semantic Web is about data
modelling
• The
base level of RDF is the triple:
{subject, predicate, object}
• Examples
{[I], rdf:type, foaf:Person}
{[I], foaf:name, “Michael Souris”}
{[I], foaf:mbox,mailto:[email protected]}
• And
{foaf:name, rdf:type, rdf:Property}
11/6/2015
Slide 10 of 35
RDF triples define a graph data
structure
foaf:Person
rdf:type
foaf:name
Michael Souris
foaf:mbox
mailto:[email protected]
11/6/2015
Slide 11 of 35
.. which can be serialized in XML
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:foaf="http://xmlns.com/foaf/0.1/">
<foaf:Person>
<foaf:name>Michael Souris</foaf:name>
<foaf:mbox rdf:resource="mailto:[email protected]" />
</foaf:Person>
</rdf:RDF>
11/6/2015
Slide 12 of 35
.. and N3
@prefix rdf <http://www.w3.org/1999/02/22-rdf-syntaxns#>
@prefix foaf <http://xmlns.com/foaf/0.1/>
[] a foaf:Person;
foaf:name “Michael Souris”;
foaf:mbox <mailto:[email protected]> .
11/6/2015
Slide 13 of 35
Web
11/6/2015
Slide 14 of 35
Merging RDF data from different
sources
Media metadata database:
../presentation.ppt
dc:creator
dc:date
dc:description
Talk on Semantic Web
org:email
2006-04-23
mailto:[email protected]
11/6/2015
Slide 15 of 35
The second datasource
Organization database:
org:Engineer
rdf:type
vcard:FN
Steve Cayzer
org:worksOn
org:email
ex:SemanticBlogging
mailto:[email protected]
11/6/2015
Slide 16 of 35
Two datasources merged
Merged database:
org:Engineer
../presentation.ppt
dc:creator
dc:date
rdf:type
vcard:FN
dc:description
Talk on Semantic Web
Steve Cayzer
org:worksOn
org:email
ex:SemanticBlogging
2006-04-23
mailto:[email protected]
11/6/2015
Slide 17 of 35
Linking foaf profiles …
foaf:Person
rdf:type
foaf:name
Michael Souris
foaf:mbox
mailto:[email protected]
11/6/2015
Slide 18 of 35
… into a social network …
foaf:Person
foaf:Person
rdf:type
rdf:type
foaf:name
Donald Canard
foaf:name
foaf:knows
foaf:mbox
mailto:[email protected]
11/6/2015
Michael Souris
foaf:mbox
mailto:[email protected]
Slide 19 of 35
… and serialized for machines …
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:foaf="http://xmlns.com/foaf/0.1/">
<foaf:Person>
<foaf:name>Michael Souris</foaf:name>
<foaf:mbox rdf:resource="mailto:[email protected]" />
<foaf:knows>
<foaf:Person>
<foaf:mbox
rdf:resource="mailto:[email protected]" />
<foaf:name>Donald Canard</foaf:name>
</foaf:Person>
</foaf:knows>
</foaf:Person>
</rdf:RDF>
11/6/2015
Slide 20 of 35
.. or visualised by people
The Friend of a Friend
(FOAF) project is about
creating a Web of
machine-readable
homepages describing
people, the links between
them and the things they
create and do.
Distributed RDF/XML
records describing
people, who they know,
projects they work on…
11/6/2015
Slide 21 of 35
Semantic Web is also about global
sharing of models
•
share data but also share models (or vocabularies)
•
Properties and Classes have URIs (so we can specify their
semantics: ‘knows’ = met/friend/emailed/aware_of)
URIs must be globally unique (can use URLs)
•
•
Many shareable models eg documents (dublin core), images
(EXIF!), people (foaf), lifesciences (ways of talking about
genes, proteins), museums (items),
•
Modelling is not new; what’s new is that we can share
models globally and mix them up – eg ‘find me photos
(image metadata) about my friends (social network)’
11/6/2015
Slide 22 of 35
The Fractal Semantic Web
•
11/6/2015
From http://www.w3.org/2005/Talks/1110-iswc-tbl/
Slide 23 of 35
Technology
11/6/2015
Slide 24 of 35
Semantic Web Technologies
Proof
Rules and logic
Query
Modelling
language for
data (and
metadata)
Universal
(web-based)
naming
scheme
11/6/2015
OWL and RDFS
RDF
Digital Signature
Trust
XML + Namespaces + xmlschema
URI
Slide 25 of 35
Semantic Web Technologies
Ontology languages
for representing the
semantics of data
Modelling
language for
data (and
metadata)
Universal
(web-based)
naming
scheme
11/6/2015
Proof
Rules and logic
Query
OWL and RDFS
RDF
XML + Namespaces + xmlschema
URI
Digital Signature
Trust
RDF, RDFS, OWL
standardised February
2004
Slide 26 of 35
Semantic Web Ontology Languages
RDFS
Student is a subclass of Person
friend is a subproperty of knows
The domain and range of knows is Person
OWL
Lions only eat meat
The ‘ancestor’ relationship is transitive
People have exactly one shoesize
An email address unambiguously identifies one
person
11/6/2015
Slide 27 of 35
Semantic Web Technologies
Query and data
access protocol
Ways of transforming
data between
ontologies
Current research areas
Ontology languages
for representing the
semantics of data
Modelling
language for
data (and
metadata)
Universal
(web-based)
naming
scheme
Proof
Rules and logic
Query
OWL and RDFS
RDF
Digital Signature
Trust
XML + Namespaces + xmlschema
URI
RDF, RDFS, OWL standardised Feb 2004
SPARQL query language: W3C Working Draft 4 October 2006
Rule Interchange Format working group chartered 2005
11/6/2015
Slide 28 of 35
Examples
11/6/2015
Slide 29 of 35
Aktors
Integration of
distributed…
•
RAE Data
•
Geographical Location
•
ACM Taxonomy
•
Internal Research Data
•
…
http://www.aktors.org/akt/
http://triplestore.aktors.org/SemanticWebChallenge/
11/6/2015
Slide 30 of 35
An HP Example
The Semantic Web Environmental Directory (SWED) is a prototype
of a new kind of directory of environmental organisations and
projects. Our goal is to develop a sustainable (realistically
maintainable) and easy to use directory about environmental
organisations and projects throughout the UK.
www.swed.org.uk
11/6/2015
Slide 31 of 35
Conclusions
11/6/2015
Slide 32 of 35
A side note on XML
•
RDF is not XML (though it can be expressed in XML)
•
The semantic web is about global sharing of
information models
•
RDF describes the information model
•
RDF can be expressed in XML (or N3, or drawn as a
graph…)
•
XML Schema is all about syntax and so has limited use
for RDF
•
RDF Schema is all about the model
11/6/2015
Slide 33 of 35
Take home messages
•
The semantic web is about globally sharing, processing
and integrating information.
•
RDF is a model.
•
RDF is not XML, though it may be serialized in XML
•
Semantic web technologies range from production ready
(the lower layers) to active research areas (the upper layers)
11/6/2015
Slide 34 of 35
11/6/2015
Slide 35 of 35
Tutorials
Official page: http://www.w3.org/2001/sw/
•
Sean Palmer – programmers intro (2001) dated but quite nice
http://infomesh.net/2001/swintro/
•
Morbus Iff (creator of Amphetadesk)
“The Semantic Web 1-2-3” good overview
http://disobey.com/detergent/2002/sw123/
•
My introductory lecture (XML biased)
http://www.hpl.hp.com/personal/Steve_Cayzer/downloads/040312_semweb_public_v
ersion.pdf
11/6/2015
Slide 36 of 35
Resources – interviews and
presentations
•
W3C list http://www.w3.org/2001/sw/#events
•
Sir Tim Berners-Lee interview September 2004
•
Tom Passin interview August 2004
•
Aaron Swartz interview January 2004
•
Eric Miller (W3C semantic web activity lead) talk, early 2004
•
The Semantic Web,
http://www.internetnews.com/dev-news/article.php/340962
http://www.javaranch.com/journal/200408/Journal200408.jsp#a2
http://iron.wootest.net/aaron_swartz.php
http://www.w3.org/2004/Talks/0120-semweb-umich/slide1-0.html
11/6/2015
Tim Berners-Lee 2002
Slide 37 of 35
Resources – the controversy
•
Mark H Butler Is the Semantic Web Hype? Manchester Metropolitan University, 12th March
2003. Highlights some perceived difficulties ahead.
•
“Themes and metaphors in the semantic web discussion” November 15, 2003, Peter Van
Dijck http://www.poorbuthappy.com/ease/semantic/
Summarises the Clay Shirky article quoted earlier: “The Semantic Web, Syllogism, and
Worldview” 2003
http://www.shirky.com/writings/semantic_syllogism.html
•
“A no-nonsense guide to Semantic Web specs for XML people (Part I)” July 14, 2004
Stefano Mazzocchi http://www.betaversion.org/~stefano/linotype/news/57/ (also serves
as a tutorial)
•
Collaborative knowledge gardening August 2004 Jon Udell
http://www.infoworld.com/article/04/08/20/34OPstrategic_1.html
Do we actually need an ontology?
•
Curing the Web's Identity Crisis 2003 Steve Pepper
http://www.ontopia.net/topicmaps/materials/identitycrisis.html
The problems with URIs
11/6/2015
Slide 38 of 35
Resources - books
•
“The Explorer’s Guide to the semantic web” Tom Passin (2004).
Probably the best introductory book
http://www.manning.com/passin
•
“Practical RDF” Shelley Powers (2003)
RDF/XML focused but well written and highly recommended
http://www.oreilly.com/catalog/pracrdf/
•
The Semantic Web: A Guide to the Future of XML, Web Services and
Knowledge Management Michael C. Daconta et al.
http://www.amazon.co.uk/exec/obidos/ASIN/0471432571/
11/6/2015
Slide 39 of 35
Resources - articles
•
W3C articles http://www.w3.org/2001/sw/#pub
•
The Semantic Web, Scientific American, May 2001, Tim Berners-Lee,
James Hendler and Ora Lassila
•
Integrating applications on the Semantic Web
Jim Hendler, Tim Berners-Lee and Eric Miller, Journal IEE Japan,
122(10):676-680, 2002.
•
IEEE data engineering bulletin December 2003: Special Issue on
Making the Semantic Web Real
•
Uncle Sam's Semantic Web by Paul Ford
xml.com article, September 15, 2004
http://www.xml.com/pub/a/2004/09/15/egov.html
http://www.google.com 
11/6/2015
Slide 40 of 35
Resources – programming
•
RDF primer
•
N3 primer
•
OWL guide http://www.w3.org/TR/2004/REC-owl-guide-20040210/
•
Jena – the ‘swiss army knife’ of the semantic web, produced by HewlettPackard Laboratories in Bristol and Palo Alto
http://www.w3.org/TR/2004/REC-rdf-primer-20040210/
http://www.w3.org/2000/10/swap/Primer
http://www.w3.org/2000/10/swap/doc/
and
http://www.hpl.hp.com/semweb/jena.htm
[Try the Jena tutorial for an introduction to semweb development]
http://jena.sourceforge.net/tutorial/RDF_API/index.html
•
Protégé – Easy ontology creation, from Stanford University
http://protege.stanford.edu/
11/6/2015
Slide 41 of 35
Resources – online demos
•
TAP – semantically assisted Google!
•
FOAF (Friend of a Friend)
http://tap.stanford.edu/
Online demo at http://ontap.stanford.edu/sail
−
−
•
FOAFnaut (http://www.foafnaut.org/)
FOAFCorp (http://www.grorg.org/2002/10/foafcorp/)
Photo annotation:
−
−
W3 conference photos (http://w3photo.org/ )
Storymill (http://storymill.net/ )
•
HP Semantic Web environment directory (
•
AKTors http://triplestore.aktors.org/SemanticWebChallenge/
11/6/2015
http://www.swed.org.uk/
)
Slide 42 of 35
Resources – commercial applications
and startups
Just a selection:
•
Adobe XMP
•
Brandsoft http://www.brandsoft.com/Home
•
Network Inference http://www.networkinference.com/
•
Semaview http://www.semaview.com/
•
Immuexa (creators of Storymill) http://immuexa.com/
•
Siderean http://www.siderean.com/
•
Ontopia (not RDF!) http://www.ontopia.net/
11/6/2015
Slide 43 of 35
HP Labs semweb site
http://www.hpl.hp.com/semweb/
11/6/2015
Slide 44 of 35
Additional Slides
11/6/2015
Slide 45 of 35