Abstract: The ontology mapping is complex because of the large size of ontology. Aiming at the defect of existing ap- proaches,this paper presented a new way which is based on the module extractedion to realize the large ontology parti- tion and mapping. We extracted the ontology modules by the I_aplace Matrix of the dependency graph, and computed the module similarity, then got the mapped modules. The empirical results indicate that our method can achieve ontology partition and enhance the mapping efficiency.

Key words: Large ontology, Word stem, Module extraction, Similarity of module suject