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The Semantic Web (Current State and Directions)

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  1. The Semantic Web(Current State and Directions) Deborah McGuinness Associate Director and Senior Research Scientist Knowledge Systems Laboratory Stanford University Stanford, CA USA dlm@ksl.stanford.edu http://www.ksl.stanford.edu/people/dlm NSF/NCAR October 30, 2002

  2. Outline • Web: today and tomorrow • The key to tomorrow’s web is semantics • Semantics on the web requires: • Language for encoding meaning (XML, RDF/S -> DAML+OIL, OWL) • Ontologies (Term descriptions and their interrelationships) • Tools • Conclusion and Pointers NSF/NCAR October 30, 2002

  3. Human Human Human Human Today: Rich Information Source for Human Manipulation/Interpretation NSF/NCAR October 30, 2002

  4. “I know what was input” The web knows what text was input (and is great at information dissemination) but does little interpretation, manipulation, integration, and action. Analogous to a new assistant who is thorough yet lacks common sense, context, adaptability, and the ability to interpret for you NSF/NCAR October 30, 2002

  5. Human Agent Agent Tomorrow: Rich Information Source for Agent Manipulation/Interpretation NSF/NCAR October 30, 2002

  6. “I know what was meant” • Understand term meaning and user background • Interoperable (can translate between applications) • Programmable (thus agent operational) • Explainable (thus maintains context and can adapt) • Capable of filtering (thus limiting display and human intervention requirements) • Capable of executing services NSF/NCAR October 30, 2002

  7. Layer Cake Foundation NSF/NCAR October 30, 2002

  8. Ontologies DAML/OWL-enabled web pages Semantic Markup In languages such as OWL, DAML+OIL (http://www.w3.org/2001/sw/WebOnt/, http://www.daml.org), we capture • Background info • User modeling info for • Annotating web pages (man/automatically) • Annotating services thereby limiting needs for human disambiguation input, human interpretation, multiple answer display, translation assistance, agent assistance, adaptivity support, etc.) NSF/NCAR October 30, 2002

  9. DAML/OWL Language • Web Languages • RDF/S • XML • Extends vocabulary of • XML and RDF/S • Rich ontology representation language • Language features chosen for efficient implementations DAML-ONT DAML+OIL OWL OIL Formal Foundations Description Logics Frame Systems FACT, CLASSIC, DLP, … NSF/NCAR October 30, 2002

  10. W3C WEBONT catches on…. • Includes over 50 members from over 30 international organizations. • Industry including: • Large companies such as Daimler Chrysler, EDS, Fujitsu, HP, IBM, Intel, Lucent, Motorola, Nokia, Philips Electronics, Sun, Unisys, … • Newer/smaller companies such as IVIS Group, Network Inference, Stilo Technology, Unicorn Solutions, … • Government and Not-For-Profits: • Defense Information Systems Agency, Interoperability Technology Association for Information Processing, Japan (INTAP) , Intelink Mgt Office, Mitre, • ARDA, CIA, DARPA, DIA, NCI, NIH, NIST, NSF, … • Universities and Research Centers: • Stanford University, University of Bristol, University of Maryland, University of Southamptom, … • DFKI (German Research Center for Artificial Intelligence), Forschungszentrum Informatik • Invited Experts • Well-known academics from non-W3C members NSF/NCAR October 30, 2002

  11. OWL Lite Features • RDF Schema Features • Class, rdfs:subClassOf , Individual • rdf:Property, rdfs:subPropertyOf • rdfs:domain , rdfs:range • Equality and Inequality • sameClassAs , samePropertyAs , sameIndividualAs • differentIndividualFrom • Restricted Cardinality • minCardinality, maxCardinality (restricted to 0 or 1) • cardinality (restricted to 0 or 1) • Property Characteristics • inverseOf , TransitiveProperty , SymmetricProperty • FunctionalProperty(unique) , InverseFunctionalProperty • allValuesFrom, someValuesFrom (universal and existential local range restrictions) • Datatypes • Following the decisions of RDF Core. • Header Information • imports , Dublin Core Metadata , versionInfo NSF/NCAR October 30, 2002

  12. OWL Features • Class Axioms • oneOf (enumerated classes) • disjointWith • sameClassAs applied to class expressions • rdfs:subClassOf applied to class expressions • Boolean Combinations of Class Expressions • unionOf • intersectionOf • complementOf • Arbitrary Cardinality • minCardinality • maxCardinality • cardinality • Filler Information • hasValue Descriptions can include specific value information NSF/NCAR October 30, 2002

  13. OWL Lite and OWL • Feature Synopsis: http://www.w3.org/TR/owl-features/ • Guide: http://www.w3.org/TR/owl-features/ • Reference Description: http://www.w3.org/TR/owl-ref/ • Abstract Syntax: http://www.w3.org/TR/owl-absyn/ NSF/NCAR October 30, 2002

  14. Do I have to build the ontologies myself? Maybe not….Ontologies (suitable for reuse) are exploding • Upper Level Ontologies • UNSPSC, SUO, OpenCyc, OpenDirectory, TAP, … • Specialized Ontologies • UMLS, SNOMED, GO, CIA World Fact book, DAML-S…, even vc’s – Vulcan,… • Ontology Libraries • http://www.daml.org/ontologies/ • http://www.ksl.stanford.edu/ontolingua • “Advisory” bodies • Semantic Web Science Foundation, NIST, Ontology.org, … NSF/NCAR October 30, 2002

  15. Ontologies in most areas … including the environment Quick web search yielded: • Semantic Web for Earth and Environmental Terminology –JPL. http://oceanesip.jpl.nasa.gov/sweet • National Institute for environmental eScience – Cambridge - http://www.niees.ac.uk/ • Gene Ontology – “dynamic controlled vocabulary that can be applied to all organisms”http://www.geneontology.org/ • Design and Creation of Ontologies for Environmental Information Retrieval- Telecordia -http://sern.ucalgary.ca/KSI/KAW/KAW99/papers/Kashyap1/kashyap.pdf • Ontologies of environmental applications for a digital library of scientific collections -http://dlforum.external.forth.gr:8080/papers/EnviroInfo.pdf • Waste water ontology – decision support for wastewater treatment processes -http://citeseer.nj.nec.com/ceccaroni00wawo.html • ... Many others … NSF/NCAR October 30, 2002

  16. Tools Tools developing: http://www.daml.org/tools/ Annotation Ontology Translation Browser Persistence Crawler Query Tools Editor RDMS Mapping Graph Visualizer Report Generation Transformation Search Validator Ontology Analyzer Importer Ontology Editor Inference Engine Merging Many are in research labs, but companies emerging and lasting… Network Inference, Sandpiper, Ontoprise, AppliedSemantics, Sentius, …. NSF/NCAR October 30, 2002

  17. Conclusion/Discussion • The Semantic Web is in its infancy today but is ready for applications • Markup languages, ontologies, and some tools are ready for use • Specialized tools are buildable/usable today • Semantic web can be leveraged to support: (items from Tim, Margaret, Dan, David’s presentations): interoperability, modeling, synthesis, integrity checking, prediction, information dissemination, quick start to “poor man’s managed/curated data repositories”, foundation for “richer man’s repository, foundation for new communication mode, distributed collaboration, knowledge mgmt, knowledge from data, “democratizing information”, “build between”, … • Input welcome: if you need something from the semantic web community you don’t see, tell us NSF/NCAR October 30, 2002

  18. Some Pointers • Ontologies Come of Age Paper: http://www.ksl.stanford.edu/people/dlm/papers/ontologies-come-of-age-abstract.html • OWL: http://www.w3.org/TR/owl-features/, http://www.w3.org/TR/owl-ref/ • DAML+OIL: http://www.daml.org/ , http://www.w3.org/TR/daml+oil-reference NSF/NCAR October 30, 2002

  19. Extras NSF/NCAR October 30, 2002

  20. What is an Ontology? Thesauri “narrower term” relation Frames (properties) Formal is-a General Logical constraints Catalog/ ID Informal is-a Formal instance Disjointness, Inverse, part-of… Terms/ glossary Value Restrs. NSF/NCAR October 30, 2002

  21. Stated goals of Semantic Web • Define conventions for applications that exchange metadata on the Web • Enable vocabulary semantics to be defined by communities of expertise, not W3C or other standards bodies • Provide for the fine-grained mixing of diverse metadata • Making it cost-effective for people to effectively record their knowledge. • Ultimate goal - the design of enabling technologies to support machine facilitated global knowledge exchange NSF/NCAR October 30, 2002

  22. DARPA DAML Program • Began in August 2000 Kickoff meeting • 19 Research groups supported • Initial ontology language aims to extend XML, RDF/S, benefit from frames, benefit from principled KR systems like Description Logics • DAML-ONT released in Oct. 2000 • DAML+OIL released in March 2001 NSF/NCAR October 30, 2002

  23. DAML+OIL -> W3C • W3C Webont working group formed with DAML+OIL submission as starting point http://www.w3.org/Submission/2001/12/ • Web Ontology Working Group in the W3C Semantic Web Activity aimed at “extending the semantic reach of current XML and RDF meta-data efforts. “ NSF/NCAR October 30, 2002

  24. WEBONT cont. • Quarterly Face to Face meetings in • Murray Hill: http://www.w3.org/2001/sw/WebOnt/ftf1.html • Amsterdam: http://www.w3.org/2001/sw/WebOnt/ftf2.html • Stanford: http://www.w3.org/2001/sw/WebOnt/ftf3.html • Bristol: http://www.w3.org/2001/sw/WebOnt/ftf4 • Expected recommendation status at w3c meeting in march. • Interesting Documents: • DAML+OIL submission – full spec with reference description, walkthrough, FOL and model theoretic semantics, http://www.w3.org/TR/daml+oil-reference • Use Case and requirements document: http://www.w3.org/TR/webont-req/ NSF/NCAR October 30, 2002

  25. Contact Information dlm@ksl.stanford.edu www.ksl.stanford.edu/people/dlm NSF/NCAR October 30, 2002

  26. Some Observations… • Markup Languages are growing in acceptance and expressive power • User base, tool base, ontology base growing • Ontology-enhanced applications springing up (not just in ivory towers like FindUR, eCyc, …) NSF/NCAR October 30, 2002

  27. Simple Ontology-Enhanced Apps NSF/NCAR October 30, 2002

  28. NSF/NCAR October 30, 2002