AAAI Publications, Twelfth International Conference on the Principles of Knowledge Representation and Reasoning

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The Modular Structure of an Ontology: An Empirical Study
Bijan Parsia, Thomas Schneider

Last modified: 2010-04-27


Efficiently extracting a module from a given ontology that captures all the ontology's knowledge about a set of specified terms is well-understood task. It can be solved, for instance, by locality-based modules. In contrast, extracting all modules of an ontology is computationally difficult because there can be exponentially many. However, it is reasonable to assume that, by revealing the modular structure of an ontology, we can obtain information about its topicality, connectedness, structure, superfluous parts, or agreement between actual and intended modeling. Furthermore, incremental reasoning makes use of a number of, although not all possible, modules of an ontology. Chances are that real-life ontologies have significantly fewer modules than the worst cases. We report on experiments to obtain or estimate this number and to evaluate the modular structure of an ontology where we succeeded to compute it. In that evaluation, we look at the number and sizes of the modules, as well as the relation between module sizes and number and sizes of signatures that lead to the module.


ontologies; description logics; module extraction; syntactic locality; ontology comprehension

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