Our seminar series is free and available for anyone to attend. Unless otherwise stated, seminars take place on Wednesday afternoons at 2pm in the Kilburn Building during teaching season.

If you wish to propose a seminar speaker please contact Antoniu Pop.


Justification Based Explanation in Ontologies

  • Speaker:   Dr  Matthew Horridge  (Stanford University)
  • 27th June 2013 at 14:00 in Lecture Theatre 1.4
The Web Ontology Language, OWL, is the latest standard in logic based ontology languages. It is built upon the foundations of highly expressive Description Logics, which are fragments of First Order Logic. These logical foundations mean that it is possible to compute what is entailed by an OWL ontology. The reasons for entailments can range from fairly simple localised reasons through to highly non-obvious reasons. In both cases, without tool support that provides explanations for entailments, it can be very difficult or impossible to understand why an entailment holds. In the OWL world, justifications, which are minimal entailing subsets of ontologies, have emerged as the dominant form of explanation.

In this this talk I will present work on justification based explanation techniques. In particular, I'll focus on Laconic and Precise Justifications. These are fine-grained justifications whose axioms do not contain any superfluous parts. I'll present some motivation for these kinds of justifications, give an overview of algorithms for computing them, and present the results of an empirical investigation which that shows that these algorithms perform well on large and expressive bio-medical ontologies. The result will highlight the prevalence of superfluity in real ontologies, along with the related phenomena of justification masking.
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