| Summary: | 博士 === 國立交通大學 === 資訊科學系所 === 92 === In recent years, Expert System, the system to model expert’s decision making process and help to build up knowledge systems, becomes more and more important in Computer Science domain for next generation computer systems. For constructing an Expert System, Rule Base is a widely used approach, where knowledge and expertise are represented as rules, a well-known logical knowledge representation. An inference engine is also part of a rule base, which can be used to process the rules of knowledge and inference as a human expert. It is easy to construct knowledge system using rule base since the representation of knowledge, the storage of knowledge, and the processing of knowledge are well designed in rule base system.
In this thesis, a New Object-oriented Rule Base Platform (NORBP) is proposed, which is designed to provide more flexible, efficient, maintainable, and meaningful knowledge representation, and also correspondingly knowledge systems mechanisms based on the lifecycle of an expert system we defined. In NORBP, several corresponding mechanisms are designed to provide a complete knowledge platform, including knowledge representation, knowledge acquisition, knowledge discovery, and knowledge fusion. In NORBP, the New Object-oriented Rule Model (NORM) is designed to represent knowledge according to Object-oriented concept, and knowledge relations are defined to construct the knowledge model. In order to provide KA methodology in NORBP, Concept Learning from Cases based on Semantic Distance for Knowledge Acquisition is proposed based on NORM concepts. Moreover, to acquire the knowledge of users daily behaviors, Knowledge Discovery mechanism is used for extracting knowledge from huge amount of user activities. Newly discovered knowledge in Knowledge Discovery mechanism may be redundant or conflict to existing knowledge, and Knowledge Fusion mechanism in NORBP is proposed to fuse different knowledge sources for the same knowledge domain, resolve the conflict and redundant of knowledge, and reconstruct the knowledge model in more meaningful structure.
Some implementations and experiments for NORBP are also done in this work. A Computer Assisted Learning Expert System (CAL-ES) and a Network Intrusion Detection Expert System (NID-ES) are proposed as case studies for NORBP. In the NID-ES, the mechanisms for complete NORBP lifecycle are designed, in which four systems, including Two-Layer Network Intrusion Detection System, Intrusion Detection Knowledge Acquisition System, Intrusion Detection Knowledge Mining System, and Intrusion Detection Knowledge Bases Fusion System, are implemented according to each phase in NORBP.
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