Research On The Semantic-Based E-learning Grid Portal

E-learning has become an international trend in education. E-learning combine the teaching and learning together in the environment of internet. Teachers can teach within the E-learning system, where they can conduct most of the teaching activities on the internet as they do in the real classroom. On the other hand students can learn on the internet, where they can read the learning content, submit homework, do the online test, collaborate with peers and communicate with others. E-learning system will be a revolution in the education domain.E-learning system is confronted with many problems. Two of the key problems are: 1) the problem of infrastructure construction, such as low penetration rate of computer, low Transfer Rate of internet, poor quality and stable of transfer of teaching information on broadband multimedia telecommunication network. 2) The difficulty of the sharing of teaching resources, because of redundant construction, decentralized resource, heterogeneous resources, the lack of standard and compatibility. So, to carry out effective and efficient E-learning, a new technology is needed to realize the transparent sharing of various information resources such as computing resources, knowledge resources, software resources etc. Only when these problems are solved can the large scale and multiple users' concurrent control on-line learning can be realized.Grid is a new network computing support platform since the appearance of web, the target of grid is to construct a dynamic virtual organization on the distributed, autonomous and heterogeneous resources on the networks. Semantic grid is a combination of semantic web and grid, which can make human collaborate more conveniently with the computer. Adopting grid in e-learning can realize the transparent sharing of various teaching resources and large scale and multiple users' concurrent control on-line learning. By designing an e-learning system based on grid, a new type grid emerge, which is called e-learning grid or learning grid. So it's meaningful to study how to provide individual, collaborative, and high sharing learning environment through grid and web services. Various competences can be promoted by introduceing grid into e-learning, the competences are listed below:â‘ teaching resources can be stored in various decentralized node on the grid. When students want to access the decentralized teaching resources, they need not tell the e-learning system which node the resources are stored. As a result, the transparent sharing of various teaching resources can be realized and the decentralized management of teaching resources can be fulfilled.â‘¡Dynamic virtual learning environment can be constructed, cross-domain sharing of teaching resources and collaborating can be realized, cooperative working can be more convenient, and more learning services can be provided. For example, student can share their learning resources, communicate their learning experiments, feedback their information mutually etc.â‘¢each single node in grid can execute local applications.With the competences in the new E-learning system, it is of great significance to study how to provide individual, collaborative, and high sharing learning environment through grid and web services.This paper does a series of studies in the semantic based e-learning grid portal on the basis of the student cognitive model. The model designed in the paper has achieved success in the practical applications. The major contributions of the dissertation are:1) A more detailed e-learning grid portal model(SEGP) has been designed to solve the problems stated above and semantic support has been added into the model. At the top level of SEGP is the portal which is a very important part of e-learning grid responsible for the interface of grid. Other parts or levels of e-learning grid can be combined through portal.2) A new semantic modeling method based on attribute and domain knowledge structure has been proposed on the basis of depth analysis of the problems of teaching resources modeling. For the analysis of domain knowledge structure, a series of ontology mapping rule has been designed. A trMDS model within a teaching resources information provider has been developed to fulfill the register, share and reuse of teaching resource dispersed in the various node of the Grid.3) A SEGP teaching resources retrieve model has been proposed on the basis of systematic research of the semantic retrieve. The semantic similarity calculating method has been improved in the model to strengthen the ability of semantic matching. A hybrid teaching resource semantic retrieve model has also been proposed to increase the efficiency of retrieve.4) For the SEGP learning service, the concept of learning service has been proposed based on the concept of grid service. A new e-learning grid system based on SOA has been designed in which the system is decomposed into a series of learning services which are distributed in the nodes on the Grid. So the distribute e-learning system has been realized through learning services which can be registered to the e-learning grid server and be called from client node. 5) An ontology infrastructure of student model has been proposed, in which each structure of ontology has been described, the mapping process and algorithm of domain ontology and overlay ontology has been given. A new cognitive student ontology has been designed to assemble the existing research of learning styles, cognitive traits and cognitive abilities. Better Results has been obtained by using the cognitive student ontology to reflect student cognitive different differences.