WSMO - revisited

1. WSMO - revisited SWSL phone conference, 17-06-2004 Dieter Fensel Digital Enterprise Research Institute dieter.fensel@deri.org

2. Outline • The new structure and main deliverables: • WSMO Working Group • WSML Working Group • WSMX Working Group • Links to SWSL • Rule language • Choreography/Orchestration language Dieter Fensel dieter.fensel@deri.org

3. Working Groups – general overview WSMO WG A Conceptual Model for SWS WSML WG WSMX WG A Formal Language for WSMO An Execution Environment for WSMO A Rule-based Language for SW Dieter Fensel dieter.fensel@deri.org

4. WSMO WG • Web site at http://www.wsmo.org/ • Chairs: Christoph Bussler and Dieter Fensel. • Mailing list for group members: deri-wsmo@informatik.uibk.ac.at • Mailing list for technical discussions:deri-wsmo-discussion@informatik.uibk.ac.at • Contact: dumitru.roman@deri.ie • Activity sheet: http://www.wsmo.org/2004/d6/d6.1/v1/Around 14 deliverables with defined editors and deadlines. • Members: http://www.wsmo.org/people.htmlCurrently 58 members. • Presentations: http://www.wsmo.org/presentations.htmlCurrently more than 45 presentations on related aspects. • Current working drafts: http://www.wsmo.org/2004/ Dieter Fensel dieter.fensel@deri.org

5. WSMO – main deliverables • Conceptual model for Semantic Web Services • WSMO Standard (D2) • WSMO Lite (D11) • WSMO Full (D12) • Choreography (D14) and Orchestration (D15) • Not yet clearly defined. • Intention: use ASMs. • Showcasing: WSMO Primer (D3.1) and Case Studies (D3.2) • Conceptual Comparison WSMO/OWL-S (D4.1) • WSMO Tutorial (D17) • WSMO in DIP(D19.1), KW(D19.2) and SEKT(D19.3) Dieter Fensel dieter.fensel@deri.org

6. WSML WG • Web site at http://www.wsmo.org/wsml • Chair: Dieter Fensel. • Mailing list for group members: deri-wsml@informatik.uibk.ac.at • Mailing list for technical discussions:deri-wsmo-discussion@informatik.uibk.ac.at • Contact: dumitru.roman@deri.ie • Activity sheet: http://www.wsmo.org/2004/d6/d6.2/v1/Around 18 deliverables with defined editors and deadlines. • Members: http://www.wsmo.org/people.htmlCurrently 16 members. • Presentations: http://www.wsmo.org/presentations.htmlCurrently 13 presentations on related aspects • Current working drafts: http://www.wsmo.org/2004/ Dieter Fensel dieter.fensel@deri.org

7. WSML – main deliverables • WSML language • WSML User language (D16.1) • WSML/XML (An XML Syntax for WSML) (D16.3) • F-logic/XML (An XML Syntax for F-logic) (D16.2) • WSML OWL Syntax (D16.5) – not yet defined • Inferencing with WSML • Inferencing support for SWS: Proof Obligations (D5.1) • Inferencing Support for Semantic Web Services: Tools for Semantic Support (D5.2) • Language Evaluation and Comparison (D8) • Mapping to OWL-S (D4.3) – not yet defined. • Ontology Language API (D18) • OWL-Lite¯ (D20) Dieter Fensel dieter.fensel@deri.org

8. WSMX WG • Web site at http://www.wsmx.org/ • Chair: Christoph Bussler. • Mailing list for group members: deri-wsmx@informatik.uibk.ac.at • Mailing list for technical discussions:deri-wsmo-discussion@informatik.uibk.ac.at • Contact: michal.zaremba@deri.ie • Activity sheet: http://www.wsmo.org/2004/d6/d6.3/v1/Around 12 deliverables with defined editors and deadlines. • Members: http://www.wsmo.org/people.htmlCurrently 33 members. • Current working drafts: http://www.wsmo.org/2004/ Dieter Fensel dieter.fensel@deri.org

9. WSMX – main deliverables • WSMO Editor (D9) • WSMO Registry (D10) • Overview and Scope of WSMX (D13.0) • WSMX Conceptual Model (D13.1) • WSMX Execution Semantics (D13.2) • WSMX Mediation (D13.3) • WSMX Architecture (D13.4) • WSMX Implementation (D13.5) – first version expected end of June, 2004. Dieter Fensel dieter.fensel@deri.org

10. Links to SWSL • Rule language effort • Choreography and orchestration language Dieter Fensel dieter.fensel@deri.org

11. Rule language effort Six points I want to make: • DL is an interesting subset of 1st order logic • HL is an interesting subset of 1st order logic • Full 1st order logic is an interesting language • Pure logics are cumbersome tools for modeling • SWRL is crap • A useful rule language for the semantic web must follow a DL-minimalistic approach Dieter Fensel dieter.fensel@deri.org

12. (1) DL is interesting • because of its decidability/tractability properties • spoken for the man on the street it is the fragment of logic that can be computationally explored around the existential quantifier. • it is therefore worth to become standardized in OWL • besides the fact that I do not like at all OWL-Lite which is an overkill, • a smooth extension of RDFS would have been much more appropriate. • Therefore we develope OWL-Flight (restricting OWL-Lite to DLP and extend it by RDF features).      Dieter Fensel dieter.fensel@deri.org

13. (2) HL is interesting • because of its decidability/tractability properties • Spoken for the man on the street it is the fragment of logic that can be computationally explored around the all quantifier • without function symbols it is decidable and • with minimal-model semantics function symbols, non-monotinicity of negation, and even transitive closure (an extension of first order logic) can be expressed. • It is therefore worth to become standardized by W3C, however, not in a way that destroy all features of rule languages by mixing it up too much with DL type of expressions. • Therefore we develope OWL-Flight (restricting OWL-Lite to DLP and extend it by rule features).   Dieter Fensel dieter.fensel@deri.org

14. (3) First order logic is interesting • In oposition to DLs and HLs it provides significant more flexibility in writing down required axioms. • This language is not fully mechanizable in terms ofreasoning support, however, • many interesting theorems can be proven and the theorem prover community has made significant progress over the last years. • First order language could define the common umbrella, where DLs and HLs are sublanguages and unified. • Therefore, we will redefine OWL-Full. Dieter Fensel dieter.fensel@deri.org

15. (4) Pure logic is cumbersom • Pure logics is a cumbersome tool for modeling • Therefore, extensions like Flogic that allow quantification over classes and attributes are that helpful. • W3C recommendations should care for this if they want to make their languages widely adopted. • OWL-Flight provide these features. Dieter Fensel dieter.fensel@deri.org

16. (5) I strongly dislike SWRL • since it spoils the nice properties of rule languages for the price of defining the rule language as an extension of DLs. • SWRL is meaningless since it defines a syntactical restriction of 1st order logic without any computational justification. • SWRL is as undecidable and untractable as first order logic. • Therefore, it is meaningless to syntactically restrict first order logic in that way. Dieter Fensel dieter.fensel@deri.org

17. (6) A useful rule language for the semantic web must follow a different approach • It should emply the full power of the HL fragment and include DL features only in case they do not harm this language type. • Therefore, a HL language should be defined as an extension of RDFS and/or OWL-Lite (where OWL Lite is reduced to an actual lite subset of DL). • That is the rationale underlying OWL-Flight. Dieter Fensel dieter.fensel@deri.org

18. Choreography and orchestration • Choreography is about communication • Orchestration is about task decomposition • Both elements require the specification of dynamics • We are using Abstract State Machines as a point of departure to formalize the basic principles for these languages. • And we are very eager to learn from you! Dieter Fensel dieter.fensel@deri.org

19. </ WSMO > <Q&A>