Domain Ontology-based Semantic Information Retrieval And Related Technologies

The fundamental reason that lead to the poor quality of information retrieval lies in the lack of semantics in retrieval tools and retrieval proccess;The false understandings of users' information are cause by the simple and mechanical match on the level of grammar; The defects are related to the existing information,such as the false retrieval and the omitting retrieval, ontology is the description of the objective existence and their mutual relationship. Information retrieval based on ontology is the retrieval based on semantics, which make up for the shortage of the traditional key words retrieval system. The introduction of ontology based on semantic information retrieval technology enables information retrieval system to gain a better guarantee in precision and recall.First, the purpose and significance of the subject are stated, and the current research based on the ontology of the information retrieval research situation on the ontology and information retrieval of ontology both abroad and at home is analyzed. Besides,the relevent theories of ontology and information retrieval are introduced .A new constructing methods in domain ontology is advanced on the basis of comparison and analysis of all kinds of ontology constructing ways,abideing a gereral principles of ontology construction and summarizing up all kinds of advantages of ontology constructing way, a strong theoretical support for the system of semantic retrieval based on ontology is achived.Secondly, from such respects as the semantic pretreatment of document, the improvement of semantic similarity based on ontology and the calculation method of the relativity ,and searching expansion skill , and Inverted Index, the key technology,which is needed for constructing semantic retrieval system based on ontology is deeply studied. And a framework of semantic retrieval system based on ontology is suggested , and the implementation process of system model is introduced in detailed. Thirdly, based on the above theoretical research ,the dissertation puts forward research paper search model based on ontology ,and sets up a preliminary testing ontology based on data structure papers ,and through the search function testing, the feasibility and the effectiveness of the methods are proven. Finally, and the whole text is summarized and reviewed, the prospects for the future search work is advanced.