Terminological Reasoning by Query Evaluation: A Formal Mapping of a Terminological Logic to an Object Data Model

Title Terminological Reasoning by Query Evaluation: A Formal Mapping of a Terminological Logic to an Object Data Model
Author(s) U. Reimer, P. Lippuner, M. Norrie, M. Rys
Type inproceedings
Booktitle Proc. Int. KRUSE Symp. (Knowledge Retrieval, Use and Storage for Efficiency)
Santa Cruz, California
Organization
Month August
Year 1995

Abstract

This paper is concerned with defining a formal mapping from a terminological logic to an object data model which preserves as much of the semantics of the terminological logic as possible. To this end, the paper begins by giving concise introductions into the terminological logic FRM and the object data model COCOON. It then introduces and discusses a formal mapping from FRM to COCOON. Although this mapping is tailored to these two models, it is representative for terminological logics and object data models in general because it is grounded on the paradigms underlying these formalisms. The mapping consists of two major parts. The first one is concerned with mapping a concept class description of FRM to a semantically equivalent object class definition in COCOON. The second part of the mapping deals with deriving COCOON operations from the corresponding operations on an FRM knowledge base. As the terminological inferences are the most important kinds of (query) operations, we concentrate on their mapping. We show for two kinds of inferences, one of them being the classification inference, how they are mapped to equivalent COCOON queries. Since these queries can (mostly) be submitted as a whole to the underlying database system we can take full advantage of the capabilities of the associated query optimiser. Consequently, all the results on query optimisation, on providing efficient physical access structures, as well as on parallelisation that are available in the database area become usable to make terminological inferences more efficient. This can play a crucial role in realising knowledge base systems capable of dealing with very large knowledge bases.
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