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The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
The Semantic Web: status and prospects
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The Semantic Web: status and prospects

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Keynote at Diffuse conference, Brussels, 2002

Keynote at Diffuse conference, Brussels, 2002

Published in: Technology
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  • 1. The Semantic Web: Status and Prospects Guus Schreiber University of Amsterdam Co-chair W3C Web Ontology Working Group
  • 2. 2 The Evolving Web Web of Knowledge HyperText Markup Language HyperText Transfer Protocol Resource Description Framework eXtensible Markup Language Self-Describing Documents Foundation of the Current Web Proof, Logic and Ontology Languages Shared terms/terminology Machine-Machine communication 1990 2000 2010 Berners-Lee, Hendler; Nature, 2001 DOCUMENTS DATA/PROGRAMS
  • 3. 3 Semantics for the Web: some challenges  Machine-processable representation of semantic information  Defining semantics in an OPEN environment • Adding semantics to other people’s semantics • Ability for everyone to contribute  Ability to define mappings between semantic representations • Semantic representations are context-dependent, but commonalities can/must be captured  Creating a critical mass of semantic content • In the end, this will be the critical success factor
  • 4. 4 W3C’s view on Web Semantics Semantic Web LayerCake (Berners-Lee, 99;Swartz-Hendler, 2001)
  • 5. Semantic web languages provide “external” referents for XML documents CV name education work private < > < > < > < > < > < Χς > < ναµε> <εδυχατιον> <ωορκ> <πριϖατε> CV name education work private < > < > < > < > < > < Χς > < ναµε> <εδυχατιον> <ωορκ> <πριϖατε> CV name education work private < > < > < > < > < > < Χς > < ναµε> <εδυχατιον> <ωορκ> <πριϖατε> SW languages add mappings And structure.  ωορκ ϖατε εδυχ Χς ΧςΧς Χς  CV name education work private < > < > < > < > < > <  > < > < >  <⇐⇑©∨> CV name education work private < > < > < > < > < > <  > < > < >  <⇐⇑©∨> CV name education work private < > < > < > < > < > <  > < > < >  <⇐⇑©∨> CV name education work private < > < > < > < > < > <  > <  > <  >  < ⁄‹›„ > CV name education work private < > < > < > < > < > <  > < > < >  <⇐ ⇑ © ∨>
  • 6. 6 What is an Ontology?  In philosophy: theory of what exists in the world  In IT: consensual & formal descriptionconsensual & formal description of shared concepts in a domainof shared concepts in a domain – Aid to human communication and shared understanding, by specifying meaning – Machine-processable (e.g., agents use ontologies in communication)  Ontology = key technology inOntology = key technology in semantic information processingsemantic information processing – Applications: knowledge management, e-business, industrial engineering, semantic world-wide web
  • 7. 7 Typical semantic-web use case: image search  A person searches for photos of an “orange ape”  An image collection of animal photographs contains snapshots of orang-utans.  The search engine finds the photos, despite the fact that the words “orange” and “ape” do not appear in annotations
  • 8. 8 Example semantic annotation
  • 9. 9 RDF annotation about a web resource chimpanzee scratching the head young ape08.jpg active agent posture life stage Species ontology WordNet ICONCLASS
  • 10. 10 Ontologies describes the concepts used great ape grass landsrain forest Africa chimpanzee geographical range subClassOf typical habitat
  • 11. 11 Use of semantic markup in query interfaces
  • 12. 12
  • 13. 13 Annotating with a concept: term disambiguation
  • 14. 14 W3C’s Semantic Web Activity  Started in March 2001 • Follow-up of Metadata activity  RDF Core Working Group • Revision of RDF and RDF Schema  Web Ontology Working Group • Started November 1, 2001 • 50+ members – HP, IBM, Lucent, Daimler Chrysler, Fujitsu, Intel, Sun, EDS, Motorola, Nokia, Philips, Unisys, ….  All proceedings are public • See http://www.w3.org under “Semantic Web”
  • 15. 15 RDF and RDF Schema  RDF • Baseline representation for annotations of web resources • Simple triple format • Already many tools and used in browsers such as Mozilla  RDF Schema • Base-level specification of semantics • Language constructs include: class, property, subclass subproperty • Classes and properties are themselves also resources: enables annotations about annotations
  • 16. 16 The Web Ontology Language OWL  OWL adds expressivity to RDF Schema to enable more powerful semantics: • cardinality restrictions, local range constraints, equality of resources, inverse, symmetric and transitive properties, boolean class combinations, disjointness and completeness  OWL Lite: subset of features that is easy to implement and use  OWL DL: subset of features supporting description-logic reasoning (e.g. useful for ontology construction)
  • 17. 17 OWL documents Published: • Requirements document • OWL Guide (language walkthrough) • OWL Feature synopsis • OWL Reference • OWL Semantics • OWL Test cases In preparation: • UML and XML presentation syntax
  • 18. 18 Moving to the future of the web Semantic Web LayerCake (Berners-Lee, 99;Swartz-Hendler, 2001)
  • 19. 19 Web services require ontologies Source: the Web (can’t find it anymore)
  • 20. 20 Use semantics for service composition Translate my symptoms from French and find me a pharmacy that has the necessary medicine (then compute how to get there and print the directions) Print the directions to a pharmacy which has a medicine that cures the symptoms that I will tell you (in French)
  • 21. 21 Services need web logics
  • 22. 22 Will the Semantic Web succeed?  One big plus: there is a growing need for semantic search of information  Availability of large amounts of semantic content is essential • There is a lot of content already out there.  First applications are likely to be in area of large virtual collections • E.g., cultural heritage, medicine  Web services will not work without ontologies

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