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Semantic Web Technologies for UK HE and FE Institutions: Part 2: RDF and Semantic Web Applications

Dave Beckett dave.beckett@bristol.ac.uk. Semantic Web Technologies for UK HE and FE Institutions: Part 2: RDF and Semantic Web Applications. Dave Beckett – Introduction. Dublin Core Metadata Initiative UK JISC Services - mirror.ac.uk RDN – WSE W3C Semantic Web Activity W3C RDF Core WG

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Semantic Web Technologies for UK HE and FE Institutions: Part 2: RDF and Semantic Web Applications

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

  2. 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

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

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

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

  6. 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. 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

  8. 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

  9. 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

  10. 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

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

  12. Relational Database Tables

  13. Tables in RDF

  14. Trees in RDF

  15. (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

  16. 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. 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. 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, ...

  19. 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. 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. 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

  22. 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

  23. 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

  24. 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

  25. FOAFnaut view of my semantic web

  26. 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

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

  28. 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!

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

  30. 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

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