Research Of Ontology-based Information Integration

The enterprises constructed various application systems according to specific requirements in the process of building the information technology. These systems are always distributed on geography, self-ruled on management, and heterogeneous on mode, and it is difficult to exchange and share information with the others. Thus these information sources become "detached islands of information". The main problem for information integration is that how to integrate those heterogeneity information resources to provide sharing and interoperable services for user. The traditional integration methods are always to integrate heterogonous information at syntax level and structure level and have nothing to do with the problem of semantic heterogeneity of information. Nowadays, people focus on the problem of semantic heterogeneity in information integration. Ontology provides a vocabulary to represent and communicate knowledge about specific domain and a set of relationships containing the term of the vocabulary at a conceptual level. Therefore, ontology might be used for information integration tasks because of its potential to describe the semantic of information sources and to solve the semantic heterogeneity problems.Firstly, in this thesis, current information integration methods at home and abroad are discussed, the heterogeneity problems of the information sources are analyzed and ontology-based information integration is introduced to solve the semantic heterogeneity problem. Secondly, the basic theory is introduced, which refers to the concept of ontology, as well as division methods, describing languages and tools to construct ontology. At the same time, the advantages of the method that apply ontology to information integration are also analyzed. The thesis puts forward an Ontology-based information integration architecture, which is named OBIIA. By the method of the Mediator/Wrapper, the data is not really stored, but is distributed in autonomous information sources. Information sources are wrapped by wrappers, and provide the Mediator a uniform schema. Ontology, which can solve semantic problems effectively, is applied as a tool in OBIIA model. The method of establishing global Ontology and local Ontology, as well as the mapping relations, is discussed in the thesis.