Research On Grid-based Distance Learning

"Grid" has emerged as an important new field, distinguished from conventional distributed system by its focus on large-scale resource sharing, innovative applications, and, in some cases, high-performance orientation. "Grid" is a type of parallel and distributed system that enables the sharing, selection, and aggregation of geographically distributed "autonomous" resources dynamically at runtime depending on their availability, capability, performance, cost, and users' quality-of-service requirements. Though Grid technology has not been widely used in practice, it is no doubt that it will have a prosperous prospect in many areas of research and application.Distance learning based on Internet brings great learning opportunities to students and other learners, compare with classical models of instruction and learning, distance learning has many advantages such as learning anytime and anyplace, better interactive between the learner and learning resources, etc, But there are also some drawbacks related to current distance learning. First of all it is mainly focused on the content delivery, leaving in the background the collaborative view. This is also due to the implementation of distance learning platform themselves. In Internet world, there exists various hardware and software system, much different operation system and great deal of learning resources which show in many types. So learning objects are platform-dependent and cannot be used outside the system . This makes more complicated the collaboration between actors of different systems. Furthermore, current learning platforms only support a specific learning-domain and are not able" to support learning in different domains.Grid technologies can help to solve these problems. By grid technologies it is possible to achieve the target that a wide-scale learning resource sharing in heterogeneous and geographically distributed system, so different actors (universities, teachers, learners) can cooperate each other, learning resources can be reused, learners can get grid service transparently-needn't to know how to get the service and who provide the service.Grid technologies can be practised based on two architectures-the Open Grid Service Architecture (OGSA) and the Layered Grid Architecture(LGA),but the Open Grid Service Architecture is more popular. The Open Grid Service Architecture (OGSA) joining Web Service and Grid technologies, defines an open and extensible framework for distributed and highly collaborative applications. This is done through the definition of Grid Services, an extension to standard Web Services able to manage lifetime and to permit introspection of the service itself . This could be the missing link in order to obtain an interactive, open and collaborative environment for distance learning build upon emerging network technologies and upcoming standards, open to the integration of third party solutions and/or services.In this thesis we mainly discuss and study how grid technologies are applied to distance learning, how to set up distance learning platform based on grid technologies in campus network ,and what result can be got when use grid technologies in distance learning.The thesis consists of seven chapters.The content in the first chapter includes an overview of current status of distance learning, by analyzing the advantages and disadvantages of network-based distance learning, we reach that there exists some problems to be solved, such as: most education or learning resources are developed without following distance learning standard, the heterogeneity and distribution of the Internet leads the lager-scale sharing of resources very difficult, etc. These problems has obstructed further development of the distance learning, the new technology must be used to change this, and the grid technologies is adaptive. Then in the following of the first chapter, the research plan of this thesis is given..In chapter 2 we mainly discussed the grid architecture and the outline use of the grid in distance learning. In order to make program bas...