Ontology-based Computer Supported Cooperative Learning Key Technology Research

The computer supported collaborative learning is a technology that combined computer information technology with collaborative learning, which enable people's collaborative learning from different place and at different time efficiently. Key to learning effectiveness are participants collaborative problem solving and semantic-based information retrivel. These require semantics to be expressed in a formal and unambiguous way. In this paper, the Ontology was used in collaborative problem solving and semantic-based information retrivel of CSCL.The main research is focused as following:1. Semantic expression of collaborative problem solving. A three-layered model was used to describe the collaborative problem solving in a learning group, the discussing procedure between two participants was analyzd with the support of Speech Act theory. According to the result of analysis, we proposed the use of Ontology to overcome the ambiguous semantic expression between human-human interactions. We also presented the scenario of Ontolgy-based knowledge navigation and its corresponding architecture by carefully defining its role, operation and system status.2. Concept classification and frame expression. By comparing the frame expression and logic expression, we adopt description logic for automatically classify the concepts during knowledge navigation. By introducing model theory, we investigate the concept classification in description logic and present the algorithm that transforming the Ontology defined in description logic to frame expression based on the satisfiability of concept interpretation.3. Learning resource annotation. We proposed the semantic resource annotation based on Ontology. To make the annotation flexible enough, a new method that separates the annotation and raw resource is also introduced. To solve the semantic inference problen when different Ontology library be used in same annotation file, we also investigate the different Ontology mismatches during Ontology integration and present their solutions, meanwhile, we futher present the integration Ontology library definition that consists of common Ontologylibrary and association Ontology library.4. Semantic-based information retrivel. Due to the lack of stable schema in semistructured database, it is hard for users to obtain a clear view of the structure and employ efficient queries. This paper presents an Ontology-based flexible query method. Based on the understanding of the ontology semantic of database, users can pose customized query without following the strict data schema, we further developed a concept ontology library that represents the schema of the original database and an algorithm that transforms the concept ontology library from graph to tree under flexible semantics to solve NP problem when direct query on graph.5. CSCL plateform prototype. The on-going CSCL platform was introduced, the plateform have been focused on Ontology expression and semantic processing, and can support students' collaborative learning high efficiently.