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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, pp: 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
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30/03/'07 upd 01/04/08 CmpE 588 Spring 2008 EMU 1
Inferring with Ontologies
Atilla ELÇİDept. of Computer Engineering
Eastern Mediterranean University
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Terminology:The Role of Philosophy in
SemWebA point of view by Christopher Menzel
of Texas A&M University:“Formal Ontology and Philosophical Content on the Semantic Web”,APA Symposium on Formal Ontologyand Philosophical Content on the Semantic Web, San Francisco, 28 March 2003Note “Contributions to Automated Reasoning Systems “ in the text, (local copy).
Philosophers’ point of view: Logic & Ontology by Thomas Hofweber. 2004. Entry in Stanford Encyclopedia of Philosophy.
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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.
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.
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Terminology:Inference, aka Reasoning Inference article in Wikipedia as a round
introduction of the term. 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 slides #3: Ontology spectrum #19-21: Description logics
Expressivity of reasoning languages Section 3 Reasoning in
Evaluating Reasoning Systems, NISTIR 7310 Deliverable, May 2006: 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
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Reasoning with Inconsistent OntologiesDavies 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
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Sect. 5.4- Reasoning with Inconsistent Ontologies: Inconsistency Detection Four-Valued Logic:a) Over-determinedb) Acceptedc) Rejectedd) Undetermined
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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.
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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
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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.
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
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PION Architecture
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Sect. 5.8- PION (continued): Usecases Usecases
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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.
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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.
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Tools for Reasoning / Inferring
Ontology Tools Survey, Revisited by Michael Denny W3C Semantic Web Tools Wiki page
Academic Conferences FOIS: 2008 is the fifth in the series of Formal
Ontology in Information Systems: 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) Due dates: Abstract/paper: 9 / 16 May.
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Commercial Conferences The Montague Institute organizes
teleconference roundtable discussions: MOSS 2007: Taxonomies & search (April 26,
2007). Social Tagging: Combining folksonomies &
taxonomies (May 17, 2007). For other roundtables, courses, and
events, see the Montague Institute 2008 calendar
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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 2003
(Barry Smith) Ontology, Buffalo Ontology Site. W3C Semantic Web Tools Wiki page:
Check Jena, SemWeb, Protégé, Swoop, etc.
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 soundtrack
Conrad Bock, Michael Gruninger, Don Libes, Joshua Lubell, and Eswaran Subrahmanian: Evaluating Reasoning Systems, NISTIR 7310 Deliverable, May 2006, NIST, US Dept of Commerce.
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