An Environment For Knowledge Sharing And Adaptive Application In E-Learning

This thesis aims at constructing an environment for knowledge sharing and adaptive application in e-Learning. Some investigations including architecture, knowledge semantic, knowledge management, knowledge services and knowledge aggregation are made.A layered principle is suggested to model the e-Learning knowledge environment based on metadata. A layered architecture which consists six layers down to top: network transport layer, data exchange layer, syntax layer, semantic layer, services layer and application layer is proposed, the functions and techniques in several main layers and the relationships between adjacent layers are analyzed. It unifies the relative techniques such as network application, computer application, knowledge management and education technique in the same model. The layered model reduces the design complexity, and makes the system become modular, open and effective.Based on semantic Web, ontology and knowledge base model are demonstrated, with regard to Intelligent Tutoring System techniques, education resource ontology are presented and defined in formalization, some examples are given. It includes concept ontology, domain knowledge ontology, pedagogical ontology, student model ontology, teach task ontology and teach application ontology, which provide semantic for knowledge sharing and adaptive application. The conjunction of education resource ontology are analyzed in UML (Unified Model Language), which shows education resource ontology can support well in knowledge sharing, knowledge capturing and knowledge adaptive application.On the basis of analyzing the topology of distributed system, a new knowledge management structure are introduced based on Web services technique and some important aspects of it are discussed, such as the method of establishing knowledge services, UDDI service center, LMS (Learning Management System) resource agent. The procedures of knowledge capturing in several conditions are described in UML sequence diagram. This structure benefits from both Client/Server and Peer-to-peer network. It can fulfill the needs of distributed knowledge management and open services better.The visual language Petri nets is used in adaptive knowledge aggregation for the first time. After defining basic Petri nets, Coloured Petri nets and hierarchy Coloured Petri nets, a model for adaptive knowledge aggregation named TeachNet is proposed and defined in formalization. It denotes the character of domain knowledge and student mode in coloured tokens and expresses teaching strategies with navigation structure and condition expressions, so it can support adaptive knowledge aggregation involving student model and teaching strategy visual. It provides a new method for developing knowledge aggregation tools and gives a good reference for knowledge aggregation research.At last, a prototype system for e-Learning knowledge environment are designed, the system structure, functions, data schema and some relative techniques for implementation are discussed.