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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
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Dave Beckett
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Introduction
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Dublin Core Metadata Initiative
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UK JISC Services
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mirror.ac.uk
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RDN
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WSE
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W3C Semantic Web Activity
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W3C RDF Core WG
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EU IST SWAD Europe
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Outline
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Introduce the ideas
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The technology
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Some real projects
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What you can do
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Open Issues
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History of the Web
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In 1991 Tim Berners
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Lee invents
the Web at CERN
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However in 1989...
the original proposal
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Information Management, a Proposal, Tim Berners
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Lee,
March 1989
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Searching the Web
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Same issues in 2003
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Current searches:
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Which documents contain these words and
phrases?
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Does not give you the information
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Descriptions for humans
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Must be made usable for software also
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My Data
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Maintain data where it naturally is
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PC revolution
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PC on all desktops
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Web revolution
-
everyone has web
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Centralising is unsustainable
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Distribution is more appropriate
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Web Architecture
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Universal, scalable, evolvable
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Mostly for people to interpret
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URIs for identification, linking
“the web works best when any [thing] of value
and identity has a first class object”
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Tim
Berners
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Lee
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Can link to anything
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HTML
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The Web of Markup
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Documents for people to read
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URIs linking to other documents
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Can point to anything
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... even if it doesn't exist the web
doesn't break
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To software, very little information
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XML
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The Generic File Format
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Unicode
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A tree (mostly)
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XML Schemas
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Good for databases
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Hard for humans
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No linking in core XML (but Xlink)
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Not webby
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The element of the Semantic
Web
Called the Resource Description Framework (RDF)
(picture by Tim Berners
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Lee, 2003
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01
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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
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Everything has a URI
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Resources, properties, classes
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Unbounded set of terms, 404s OK
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Layering is expected
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A graph (web) structure
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Semantic links not
<a href=”..”>text</a>
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Terms can have schemas
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RDF Vocabularies (RDF Schema)
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URIs for relationships and classes
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Good if you re
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use existing ones
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You can make your own
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Better if you re
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use and share them
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Connect them to other terms
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Formalise in a vocabulary or
ontology
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CORES declaration
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November 2002
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GILS, ONIX, LoC/MARC, CERIF,
DOI, IEEE/LOM, DC, W3C
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“... agree
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To assign URIs to our elements
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To articulate and publish policies regarding
the stability, persistence and maintenance of
the URIs assigned to the elements”
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RDF Family
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RDF itself
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RDF Schema
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vocabulary
description
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OWL Web Ontology Language
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Lots of vocabularies
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Dublin Core
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FOAF
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Friend of a Friend
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RSS 1.0, Creative Commons, AKT, Geo, ...
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OWL
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Web Ontology Language
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Web
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like linking of ontologies
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Strong formal semantics
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Compatibility with XML, RDF, XSD
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Based on mature DAML+OIL work
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Flavours
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OWL, OWL DL, OWL Lite
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Case Study
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Sun SwoRDFish
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Sun Knowledge Services group
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Create and share knowledge to solve service
issues
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Many sources of data inside organisation
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Many internal and external users
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Business rules and access control
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Want to
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Enable sharing business practice, model
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Add technology support for knowledge
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Case Study
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Sun SwoRDFish
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Open standards based
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RDF, SOAP/XML, DAML+OIL
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SunSolve improved
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Enables more precise search
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Standardises product names
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Improves user experience (consistency)
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Eliminates manual maintained links
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Vocabulary
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DC + Sun element set
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Sun SwoRDFish
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Outcomes
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Organisational
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lead approach
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Integrates enterprise knowledge
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Data can remain distributed
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Capable of flexible layering
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Future opportunities for
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Better RDF
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aware searching and navigation
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Richer ontology
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aware, mining, inference
tools
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hyphen.info
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AKT
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Information on UK researchers
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RAE data (HERO)
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converted
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People, Publications, Groups
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An ontology in RDF, OWL
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akt:Award, akt:Degree, akt:Academic
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Degree
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CS in the UK
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extracted from HTML
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People, Publications, Projects
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Friend of a Friend (FOAF)
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People
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who they know, what they do
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Tracking provenance
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who said what
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FOAFNaut (SVG)
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visualising
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FOAF Explorer (web)
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browsing
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FOAFbot (IRC)
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conversational
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... 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?
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Data
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centric description so
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far
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Processing of these involves
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Discovery of data, schemas, vocabularies
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Query, Rules, Inference
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Transferring RDF
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HTTP, SOAP payloads
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Web Services
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however web built in REST model
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Web Service Choreography
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DAML
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S, planning
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Semantic Grid
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Opportunities
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Sharing and syndicating descriptions
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Common vocabularies between services
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Richer, deeper specialised vocabularies
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Less yet
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another
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XML
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format
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Semantics with services
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Action!
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Webize your data processing tools
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Adapt to an unbounded web world
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Semantic web ideas and standards
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Model your world, not your documents
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Use RDF to transfer description
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NOT: convert all your data to RDF
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Although convert it if you like!
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Questions?
Thank You
dave.beckett@bristol.ac.uk
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References
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Architecture of the World Wide Web, W3C
Working Draft, W3C TAG
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Nodes and Arcs 1989
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1999: WWW history and
RDF, Dan Brickley
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SwoRDFish presentation, Kathy MacDougal,
Sun at W3C Tech Plenary, March 2003
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Why the RDF model is different from the XML
model, Tim Berners
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Lee
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