Research Of Ontology Extraction Method And Supporting Tools Faced To Database

As a modeling tool which could describe concepts on both of semantic and knowledge layers, ontology could solve two important knowledge engineering problems: knowledge sharing and knowledge reusing. In recent years, ontology has become a research focus in the field of artificial intelligence, which mainly studies ontology representation, ontology building, ontology integration, ontology application and so on.To reuse and share the knowledge in existing knowledge systems, it's necessary to get domain ontology based on the existing system. At present, most ontology are obtained by the hands of domain experts, which has many disadvantages such as complexity of the project, strongly depending on the experts, too slow for building and so on. To avoid the weakness above, the database resource should be used to build the ontology and in this paper the research of ontology extracting based on relational database is represented.At the beginning of this paper, a plan of ontology extracting method is forwarded, which includes four steps: information extraction from relational database, concepts in ontology generation, pointing out the relationship of the concepts, integration with existing ontology. Then the research of concepts generation is described, which is finished by a new idea: firstly generating middle entities from database and then turning middle entities into concepts in the ontology. The middle entity is defined in the paper.The last two steps of ontology generation belong to ontology integration. Then the methods of ontology integration are studied.