1. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU1 Inferring with Ontologies Atilla ELÇİ Dept. of Computer Engineering Eastern Mediterranean University

2. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU2 Terminology: The Role of Philosophy in SemWeb A point of view by Christopher Menzel of Texas A&M University: “Formal Ontology and Philosophical Content on the Semantic Web”, APA Symposium on Formal Ontology and Philosophical Content on the Semantic Web, San Francisco, 28 March 2003 Note “Contributions to Automated Reasoning Systems “ in the text, (local copy).the textlocal copy Philosophers’ point of view: Logic & Ontology by Thomas Hofweber. 2004. Entry in Stanford Encyclopedia of Philosophy.Logic & Ontology Thomas Hofweber

3. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU3 Terminology: Logic & Inference  Descriptive Logic versus Rule-based dilemma: RuleML approach: Ch.5 in A Semantic Web Primer by Grigoris Antoniu & Frank van Harmelen, The MIT Press, 2004. pp: 151-178.Ch.5  Basic terms: L/FOL/SOL: reference the short intro in Passin Section 6.2- “All logics aren’t created equal”  Inference article in Wikipedia as a round introduction of the term. Inference

4. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU4 Terminology: Inference, aka Reasoning  Inference article in Wikipedia as a round introduction of the term. Inference An example: the classic syllogism Automatic logical inference Inference and uncertainty: Nonmonotonic Reasoning  "Evaluating Reasoning Systems: Ontology Languages " Ontolog Mini Series by Professor Michael Gruninger: study slidesEvaluating Reasoning Systems: Ontology Languages Ontolog Mini Series #3: Ontology spectrum #19-21: Description logics

5. Expressivity of reasoning languages  Section 3 Reasoning in Evaluating Reasoning Systems, NISTIR 7310 Deliverable, May 2006:Evaluating Reasoning Systems 3.1 Introduction to Reasoning 3.2 Representation Languages:  3.2.1 First-Order Logic: define.  3.2.3.4 Second-Order Logic  3.2.4 Reified First-Order Logics  3.2.5 Description Logics  3.2.6 Web Languages  3.2.6.1 RDF/S  3.2.6.2 OWL  3.2.8 Nonmonotonic Logics 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU5

6. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU6 Reasoning with Inconsistent Ontologies Davies et al. Ch. 5, pp: 71-92:  All sections are included, but especially the following.  Def.: Inconsistency: not consistent!  Approaches to reasoning w/inconsistency Reject: classical inference cannot cope with it Live with it: apply non-standard reasoning meth. This chapter.  Reasons for inconsistency: Mis-representation of deafult Polysemy Migration from a nother formalism Due to multiple sources

7. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU7 Sect. 5.4- Reasoning with Inconsistent Ontologies: Inconsistency Detection Four-Valued Logic: a) Over-determined b) Accepted c) Rejected d) Undetermined

8. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU8 Sect. 5.4 (continued)  Formal definitions on Reasoning with Inconsistent Ontologies: Soundness: inconsistency reasoning consequences must be justifiable on the basis of a consistent subset of the theory. Meaningfulness: an inconsistency reasoner is meaningfull iff all of the answers are meaningful. Local Completeness: classical reasoning consequences are the same as inconsistency reasoner consequences of a subtheory. Maximality: inconsistency reasoner computes exactly the consequences of a maximal consistent subtheory. Local soundness: Any positive answer is also clasically entailed by a consistent subtheory.

9. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU9 Selection Functions  Def.: An inconsistency reasoner uses a “selection function” to determine which consistent subsets of an inconsistent theory should be considered in its reasoning process.  Given a theory ∑ and a query Φ, a selection function is one which returns a subset of ∑ in positive number of steps.  Definitions: Linear Extension: Using monotonically increasing / decreasing selection function. Direct Relevance & k-Relevance Direct Relevance to a Set k-Relevance Monotonicity

10. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU10 Sect. 5.8- PION of SEKT Project  An inconsistency reasoner based on a linear extension strategy and the syntactic (k- )relevance-based selection function from the SEKT Project. SEKT Project  Architecture: DIG (DL I/F for Prolog) Server: Responds to “tell” & “ask” queries Main control Component: query analysis Selection Functions DIG Client: to call external reasoner Ontology Repositories

11. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU11 PION Architecture

12. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU12 Sect. 5.8- PION (continued): Usecases  Usecases

13. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU13 Sect. 5.8- PION (continued): Testing  Intended Answer (IA): = intuitive answer  Counter-Intuitive Answer (CIA): opposite  Cautious Answer (CA): IA is accept/reject but PION returns undetermined  Reckless Answer (RA): PION returns accept/reject but IA is undetermined.

14. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU14 Probabilistic Reasoning  The Ontolog Forum’s 5th event in the joint NIST-Ontolog- NCOR mini-series on "Ontology Measurement and Evaluation," on Thursday 29-Mar-2007: "Probabilistic Reasoning and Ontology Evaluation" with Professor Kenneth Baclawski (Northeastern University), Professor Kathryn Blackmond Laskey & Dr. Paulo Costa (George Mason University), and Dr. Terry Janssen (Lockheed Martin). Check ppt and soundtrack.Probabilistic Reasoning and Ontology Evaluation

15. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU15 Tools for Reasoning / Inferring  Ontology Tools Survey, Revisited by Michael Denny Ontology Tools Survey, Revisited  W3C Semantic Web Tools Wiki pageSemantic Web Tools

16. Academic Conferences  FOIS: 2008 is the fifth in the series of Formal Ontology in Information Systems: FOIS2008 is the fifth Saarbrücken, Germany Oct 31st - Nov 3rd 2008 co-located with ISWC 2008 Abstract/paper due date: 22/24 April. Check topics.  ISWC: 7th International Semantic Web Conference (ISWC) ISWC 2008, Karlsruhe, Germany (Oct 26 - 30) ISWC 2008, Karlsruhe, Germany Due dates: Abstract/paper: 9 / 16 May. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU16

17. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU17 Commercial Conferences  The Montague Institute organizes teleconference roundtable discussions: MOSS 2007: Taxonomies & search (April 26, 2007). MOSS 2007 Social Tagging: Combining folksonomies & taxonomies (May 17, 2007). Social Tagging  For other roundtables, courses, and events, see the Montague Institute 2008 calendarMontague Institute 2008 calendar

18. 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU18 References  John Davies, Rudi Studer, Paul Warren (Editors): Semantic Web Technologies: Trends and Research in Ontology-based Systems, John Wiley & Sons (July 11, 2006). ISBN: 0470025964. Ch. 5.: pp. 71-92.  Christopher Menzel (Texas A&M University): “Formal Ontology and Philosophical Content on the Semantic Web”, APA Symposium on Formal Ontology and Philosophical Content on the Semantic Web, San Francisco, 28 March 2003Formal Ontology and Philosophical Content on the Semantic Web  (Barry Smith) Ontology, Buffalo Ontology Site.Ontology  W3C Semantic Web Tools Wiki page:Semantic Web Tools Check Jena, SemWeb, Protégé, Swoop, etc.

19. References (continued)  The 4th event was held on Thursday 22-Feb-2007: "Evaluating Reasoning Systems: Ontology Languages." by Professor Michael Gruninger (University of Toronto, Canada) and Mr. Conrad Bock (NIST, USA). Speakers covered how ontologies, semantics, knowledge representation languages and logic interplay in the formal ontology space. Check ppt and soundtrackEvaluating Reasoning Systems: Ontology Languages  Conrad Bock, Michael Gruninger, Don Libes, Joshua Lubell, and Eswaran Subrahmanian: Evaluating Reasoning Systems, NISTIR 7310 Deliverable, May 2006, NIST, US Dept of Commerce.Evaluating Reasoning Systems 30/03/'07 upd 01/04/08CmpE 588 Spring 2008 EMU19