Web Explanations for Semantic Heterogeneity Discovery Pavel Shvaiko 2 nd European Semantic Web Conference (ESWC), 1 June 2005, Crete, Greece work in collaboration

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  • Web Explanations for Semantic Heterogeneity DiscoveryPavel Shvaiko2nd European Semantic Web Conference (ESWC), 1 June 2005, Crete, Greece

    work in collaboration with Fausto Giunchiglia, Paulo Pinheiro da Silva and Deborah L. McGuinness

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    OutlineIntroduction

    Semantic Matching

    Inference Web (IW) Framework

    Explaining Semantic Matching using IW

    Experimental Study

    Conclusions

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    IntroductionInformation sources (e.g., database schemas, classifications or ontologies) can be viewed as graph-like structures containing terms and their inter-relationships

    Matching is one of the key operations for enabling the Semantic Web since it takes two graph-like structures and produces a mapping between the nodes of the graphs that correspond semantically to each other

    Matching, however, requires explanations because mappings between terms are not always intuitively obvious to human users

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Semantic Matching

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Semantic MatchingSemantic Matching: Given two graphs G1 and G2, for any node n1i G1, find the strongest semantic relation R holding with node n2j G2We compute semantic relations by analyzing the meaning (concepts, not labels) which is codified in the elements and the structures of schemas/classificationsTechnically, labels at nodes written in natural language are translated into propositional logical formulas which explicitly codify the labels intended meaning. This allows us to codify the matching problem into a propositional validity problem

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Example: Two simple classificationsAxioms rel (Context1, Context2)D.E.A1A2(Images1Pictures2) (Europe1Europe2) (Images1 Europe1) (Europe2 Pictures2)

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    S-MatchExpl.

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Inference Web (IW) Framework

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    The IW Framework Overview

    Inference Web is a framework enabling applications to generate portable and distributed explanations for their answers

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Explaining Semantic Matching using IW

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Producing Explanations

    In order to explain mappings produced by S-Match and thereby increase the trust level of its users, we need to provide information about:

    background theories (e.g., WordNet) JSAT manipulations of propositional formulasWordNet

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Default Explanation

    A default explanation of mappings the S-Match system produces is a short, natural language, high-level explanation without any technical details. It is designed to be intuitive and understandable by ordinary users

    Query: find "European pictures"Query

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Explaining Background Knowledge

    Suppose that the agent still does not trust the answer and may want to see the sources of metadata information behind the mapping

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Explaining Logical Reasoning

    If the mappings derivation process needs to be explained, using the JSAT SAT engine, S-Match produces a trace of the DPLL procedure

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Experimental Study

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Preliminary Results

    Goal: to obtain a vision of how the S-Match explanations potentially scale to requirements of the Semantic Web

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    ConclusionsWe use the Proof Mark-up Language for representing S-Match proofs, thus facilitating interoperabilityWe use meaningful terms rather than numbers in the DIMACS format, thus facilitating understandabilityWe use the IW tools, thus facilitating customizable, interactive proof and explanation presentation and abstractionOur solution is potentially scalable to the Semantic Web requirements

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Future WorkDeveloping an environment, which efficiently exploits the IW proofs and explanations, in order to make the S-Match matching process (fully-fledged) interactive and iterativeImproving the S-Match proofs and explanations by using abstraction techniques more extensivelyConducting a user satisfaction study of the explanations Extending explanations to other SAT engines as well as to other non-SAT DPLL-based inference engines

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    References

    Project website at DIT - ACCORD: http://www.dit.unitn.it/~accord/Project website at KSL - IW: http://iw.stanford.edu/F. Giunchiglia, P. Shvaiko: Semantic matching. The Knowledge Engineering Review Journal, 18(3):265-280, 2003.F. Giunchiglia, P. Shvaiko, M. Yatskevich: S-Match: an algorithm and an implementation of semantic matching. In Proceedings of ESWS, pages 61-75, 2004.D. McGuinness, P. Pinheiro da Silva: Explaining Answers from the Semantic Web: The Inference Web Approach. Journal of Web Semantics, 1(4): 397- 413, 2004.

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003

    ESWC, June 1, 2005, Crete, Greece

    Thank you!

    The Italian-Israeli Forum on Computer Science, Haifa, June 17-18, 2003