The Ontolingua Server (Knowledge Systems Laboratory, Stanford University) is one of the few tools available today for ontology construction and sharing. We have been using this tool to construct Ecolingua, an ontology for ecological meta-data description. The representation language used by the server, Ontolingua, was created as an attempt to solve the portability problem for ontologies. It adopts a translation approach in which ``ontologies are specified in a standard, system-independent form and translated into specific representation languages'' (Gruber 1993). Following this principle, the server, indeed, provides an automatic translator to ten target languages, such as Clips, Kif, Loom and Prolog syntax. So far so good... But, when we "press the button" to translate Ecolingua and the ontologies it refers into Prolog syntax, we get a 5.3Mb file, containing clauses in an awkward Kif-like Prolog syntax of doubtful logical consistency.
This talk is about the handling of this file aiming at extracting a manageable (and hopefully consistent) knowledge base from it. We have built tools to tackle syntactic correction, consistency checking, pruning and mapping into Horn clauses. After all these we have now (only!?) 1.2Mb.
Gruber, T. R. 1993. A Translation Approach to Portable Ontology Specifications. Knowledge Acquisition 5(2):199-220.