Research On Application Of Ontology In E-Learning

With the rapid development of Internet and global requirement for life education, E-Learning which provides asynchronous education has been becoming an important application on Internet. E-Learning enables people from different place and at different time to learn efficiently.However, there are some common problems of the current E-Learning systems, such as learning resources unreused and poor learning results. In order to resolve these problems, semantics is required to be expressed in a formal and unambiguous way. Metadata standard is the criterion proposed for unifying the description of resources, and Ontolgoy is the technology proposed for expressing semantics and realizing a certain extent of reusing and sharing. So, in this paper, metadata and Ontology are used to resolve these problems from the description and organization of learning resources, and semantic-based information retrieval. The mainresearches are focused as follows:1. Relevant metadata standards. In order to unify the descriptionof learning resources, we study the relevant metadata standards that describe educational resources. By the requirement of system, we adopt DC-Education metadata to describe the resources.2. Ontology. The relevant technologies include the construction of ontology, the expression of ontology, the parsing of ontology and the query of ontology. In this paper, the four kinds of ontologies are constructed: course ontology, content ontology, context ontology and structure ontology. OWL(Web Ontology Language) is used to express these ontologies. The parsing of ontology includes the parsing of class, property and restriction. Graph-based query and RDQL-based query are introduced in the query of ontology.3. Ontology-based E-Learning System architecture (OELS). We propose an Ontology-based E-Learning System architecture. The architecture mayenable the searching of the learning resources relevant to learning requirement precisely and fast, the unifying of the description of learning resources, the improving of the reusing of learning resources and the realizing of personalized learning.4. Learning resources annotation. We use the semantic resource annotation based on metadata and Ontology. To make the annotation flexible enough, a new method that separates the annotation and raw resource is also introduced.5. The navigation of learning resources. The method of classifying learning resources in terms of course ontology, content ontology, context ontology and structure ontology is proposed. The corresponding algorithm is introduced. The navigation provides an intuitionistic retrieval way for learners.6. The semantic retrieval of learning resources. We study how to retrieve the same and relevant learning resources in semantics, and introduce the corresponding algorithm. The disposal of synonym and the semantic relevant retrieval increase the precision and recall, and thus improve learners' learning.7. The sorting of retrieval results. We focused on the sorting algorithm in terms of knowledge point relativity.8. A prototype system. We develope a prototype system. The on-going prototype system is introduced, which has been focused on Ontology expression and semantic processing, and enables the reusing of learning resources and students' learning high efficiently.