Operations on Ontologies

It is possible that one application uses multiple ontologies, especially when using modular design of ontologies or when we need to integrate with systems that use other ontologies. In this case, some operations on ontologies may be needed in order to work with all of them. We will summarize some of these operations. The terminology in this areas is still not stable and different authors may use these terms in a bit shifted meaning, and so the terms may overlap, however, all of these operations are important for maintenance and integration of ontologies.

Not all of these operations can be made for all ontologies. In general, these are very difficult tasks that are in general not solvable automatically -- - for example because of undecidability when using very expressive logical languages or because of insufficient specification of an ontology that is not enough to find similarities with another ontology. Because of these reasons these tasks are usually made manually or semi-automatically, where a machine helps to find possible relations between elements from different ontologies, but the final confirmation of the relation is left on human. Human then decides based on natural language description of the ontology elements or decides only based on the natural language names of the ontology elements and common sense.

An example of such a tool is Chimaera that helps with merging ontologies. It provides suggestions for subsumption, disjointness or instance relationship. These suggestions are generated heuristically and are provided for an operator, so that he may choose which one will be actually used. PROMT or SMART system is a similar system that provides suggestions based on linguistic similarity, ontology structure and user actions. It points the user to possible effects of these changes.

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(c) Marek Obitko, 2007 - Terms of use