Slides for plenary talk on "Semantic Web Technologies for UK HE and FE Institutions" given by Dave Beckett and Brian Kelly at the IWMW 2003 event held at the University of Kent on 11-13 June 2003. See http://www.ukoln.ac.uk/web-focus/events/workshops/webmaster-2003/sessions/#talk-5

1. 1
Semantic Web Technologies for
UK HE and FE Institutions:
Part 2: RDF and Semantic Web Applications
Dave Beckett
dave.beckett@bristol.ac.uk

2. 1
Dave Beckett – Introduction
• Dublin Core Metadata Initiative
• UK JISC Services - mirror.ac.uk
• RDN – WSE
• W3C Semantic Web Activity
• W3C RDF Core WG
• EU IST SWAD Europe

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Outline
• Introduce the ideas
• The technology
• Some real projects
• What you can do
• Open Issues

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History of the Web
• In 1991 Tim Berners-Lee invents
the Web at CERN
• However in 1989...
the original proposal

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Information Management, a Proposal, Tim Berners-Lee,
March 1989

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Searching the Web
• Same issues in 2003
• Current searches:
– Which documents contain these words and
phrases?
• Does not give you the information
– Descriptions for humans
– Must be made usable for software also

7. 1
My Data
• Maintain data where it naturally is
• PC revolution – PC on all desktops
• Web revolution - everyone has web
• Centralising is unsustainable
• Distribution is more appropriate

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Web Architecture
• Universal, scalable, evolvable
• Mostly for people to interpret
• URIs for identification, linking
“the web works best when any [thing] of value
and identity has a first class object” - Tim
Berners-Lee
• Can link to anything

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HTML – The Web of Markup
• Documents for people to read
• URIs linking to other documents
• Can point to anything
• ... even if it doesn't exist the web
doesn't break
• To software, very little information

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XML – The Generic File Format
• Unicode
• A tree (mostly)
• XML Schemas
– Good for databases
– Hard for humans
• No linking in core XML (but Xlink)
• Not webby

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The element of the Semantic
Web
Called the Resource Description Framework (RDF)
(picture by Tim Berners-Lee, 2003-01-28)

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Relational Database Tables

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Tables in RDF

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Trees in RDF

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(Semantic) Web Fundamentals
• Everything has a URI
– Resources, properties, classes
• Unbounded set of terms, 404s OK
• Layering is expected
• A graph (web) structure
• Semantic links not <a href=”..”>text</a>
• Terms can have schemas

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RDF Vocabularies (RDF Schema)
• URIs for relationships and classes
• Good if you re-use existing ones
• You can make your own
• Better if you re-use and share them
• Connect them to other terms
• Formalise in a vocabulary or
ontology

17. 1
CORES declaration
• November 2002
• GILS, ONIX, LoC/MARC, CERIF,
DOI, IEEE/LOM, DC, W3C
• “... agree
– To assign URIs to our elements
– To articulate and publish policies regarding
the stability, persistence and maintenance of
the URIs assigned to the elements”

18. 1
RDF Family
• RDF itself
• RDF Schema – vocabulary
description
• OWL Web Ontology Language
• Lots of vocabularies
– Dublin Core
– FOAF – Friend of a Friend
– RSS 1.0, Creative Commons, AKT, Geo, ...

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OWL – Web Ontology Language
• Web-like linking of ontologies
• Strong formal semantics
• Compatibility with XML, RDF, XSD
• Based on mature DAML+OIL work
• Flavours – OWL, OWL DL, OWL Lite

20. 1
Case Study – Sun SwoRDFish
• Sun Knowledge Services group
– Create and share knowledge to solve service
issues
– Many sources of data inside organisation
– Many internal and external users
– Business rules and access control
• Want to
– Enable sharing business practice, model
– Add technology support for knowledge

21. 1
Case Study – Sun SwoRDFish
• Open standards based
– RDF, SOAP/XML, DAML+OIL
• SunSolve improved
– Enables more precise search
– Standardises product names
– Improves user experience (consistency)
– Eliminates manual maintained links
• Vocabulary – DC + Sun element set

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Sun SwoRDFish – Outcomes
• Organisational-lead approach
• Integrates enterprise knowledge
• Data can remain distributed
• Capable of flexible layering
• Future opportunities for
– Better RDF-aware searching and navigation
– Richer ontology-aware, mining, inference
tools

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hyphen.info – AKT
• Information on UK researchers
• RAE data (HERO) – converted
– People, Publications, Groups
• An ontology in RDF, OWL
– akt:Award, akt:Degree, akt:Academic-Degree
• CS in the UK – extracted from HTML
– People, Publications, Projects

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Friend of a Friend (FOAF)
• People - who they know, what they do
• Tracking provenance – who said what
• FOAFNaut (SVG) – visualising
• FOAF Explorer (web) – browsing
• FOAFbot (IRC) – conversational
• ... plus can be used with anything else

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FOAFnaut view of my semantic web

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Where are the services? Portals?
• Data-centric description so-far
• Processing of these involves
– Discovery of data, schemas, vocabularies
– Query, Rules, Inference
– Transferring RDF – HTTP, SOAP payloads
– Web Services – however web built in REST model
– Web Service Choreography – DAML-S, planning
– Semantic Grid

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Opportunities
• Sharing and syndicating descriptions
• Common vocabularies between services
• Richer, deeper specialised vocabularies
• Less yet-another-XML-format
• Semantics with services

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Action!
• Webize your data processing tools
• Adapt to an unbounded web world
• Semantic web ideas and standards
• Model your world, not your documents
• Use RDF to transfer description
• NOT: convert all your data to RDF
– Although convert it if you like!

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Questions?
Thank You
dave.beckett@bristol.ac.uk

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References
• Architecture of the World Wide Web, W3C
Working Draft, W3C TAG
• Nodes and Arcs 1989-1999: WWW history and
RDF, Dan Brickley
• SwoRDFish presentation, Kathy MacDougal, Sun
at W3C Tech Plenary, March 2003
• Why the RDF model is different from the XML
model, Tim Berners-Lee