Research Of Modeling And Applications Of Knowledge Base System Based On Ontology

In the study of Intelligent Tutoring System (ITS), knowledge base system is viewed as a choke point that restricts its effectiveness and practicality. The main reasons are as follows: firstly, the knowledge in knowledge base is not able to meet the needs of the system, because on the one hand, it is impossible and unrealistic to make it all-inclusive, and on the other hand, the representation of knowledge also restricts the functions of the systems; secondly, though many intelligent instructional systems have been developed, seldom knowledge bases were designed utilizing method of knowledge engineering, which certainly affected the management, retrieving and sharing of the knowledge, and thus the maintenance and expansion of the systems. Therefore, how to build a knowledge base system becomes one of the key points in the study of ITS.The representation of knowledge and its reasoning mechanism shall not be the only things to be emphasized, because large knowledge base systems, which need the sharing and transferring of knowledge, should be developed according to the theory of modeling.The modeling of Ontology-based knowledge base system is one of the research hot spots in knowledge engineering. The significance of our introduction of ontology modeling method into educational technology is that the subject knowledge base, which is established according to ontology modeling method and related knowledge representation standard and exchange protocol, would benefit for the exchanging, transferring and sharing of knowledge. Ontology, in its formalization way, represents basic concepts, attributes, processing methods and inner relationships of knowledge in subject areas. This representation can be reusable and shareable, and make it convenient for the knowledge to be searched. Ontology-based subject knowledge base systems are of high reliability, because the correctness of formal ization can be checked through even more reliable software. Representation of the formal ization of tasks can be standardized by ontology, which is helpful to the analysis of tasks, and to the explicit definition of the roles of learners and systems in instructional process and the tasks of intelligent instructional process. Ontology based system modeling can make the structure, document and coding of the system even more distinct, thus making it easy to be maintained.This article studies the ontology-based modeling method of subject knowledge base system, and then applies the method in building a domain ontology model in the subject of data structure. In the designing of study performance support system (SPSS), the application of domain knowledge ontology model effectively supports the sharing, retrieving and management of knowledge, and the development of instructional system.In Chapter one we put forward the theme to be researched, elaborate on the importance of subject knowledge base system, and review related researches.In Chapter Two, firstly, the discussion of learning technology correlative knowledge base system-Intelligent Tutoring System (ITS) and Electronic Performance Support System (EPSS), its organization and characteristic. Afterward, the discussion of learning technology structure and resources construction standardization is conducted. The system structure of learning technology standard has a directive role for the development of subject knowledge base system.Chapter Three studies the principle of building a subject knowledge system.Following points are involved in building a subject knowledge base: firstly, the representation of knowledge; secondly, the structure of knowledge base; thirdly, the management of knowledge base (including the retrieval of knowledge). Because the structure of knowledge base is determined by the representation method of knowledge, therefore, the selection of a good representation method according to specific problems or requirements of users also means the determination of knowledge base structure. In order to accurately select the representation method of knowledge and bu...