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

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Semantic Web Technologies for UK HE and FE
InstitutionsPart 2 RDF and Semantic Web
Applications

• Dave Beckett
• dave.beckett_at_bristol.ac.uk

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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

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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, linkingthe 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 lta href..gttextlt/agt
• 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

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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

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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 DAMLOIL work
• Flavours OWL, OWL DL, OWL Lite

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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

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Case Study Sun SwoRDFish

• Open standards based
• RDF, SOAP/XML, DAMLOIL
• 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
• aktAward, aktDegree, aktAcademic-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_at_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