Study And Implementaton Of Distance Education Platform Based On Virtual Classroom

Virtual Classroom is a real-time interactive virtual distance education system based on the Internet, which integrates computer, network communication and multi-media technologies. It combines the theory of Computer Supported Collaborative Work (CSCW), simulating traditional teaching functionalities, and provides a collaborated class-learning environment for distributed online teachers and students. Virtual Classroom provides an effective method for popularization education and continuing education in long distance education, and has far influence and meaning.In the preface (Chapter one), the history and present situation in China and abroad are analyzed, including problems existed in the Internet based distance education, and its prospects. The model of distance education fitting in with the actual condition of China and how to build the platform are also disccussed. And the important part that Virtual Classroom played in the long distance education is presented too. In the part of relative technologies of Virtual Classroom (Chapter two), this article studies the relative core technologies of distance education– Virtual Classroom. Generally, it extends the functionalities of teaching activities based on the Internet video meeting system. This system includes technologies and theorem of audio/video sampling, codec of audio/video, network communication, real-time transferring control, audio mixing, playback, meeting-room management, classroom control, ant etc.In the part of problem and solution of Virtual Classroom (Chapter three), this article analyzes the advantages and shortcomings of Virtual Classroom, and the causes of those advantages and shortcomings, and provide the solutions. The main causes are, absence of IP resources in China, low rate of P2P communication linkages, which increase the cost of transiting media through servers, and development of bandwidth of the Internet falls behind the speed of popularizing of the Internet application, and the unstable data flow on the Internet. An innovative solution for using end point as the distributed media-translation server is created, including its detail implementation method, which is named as mirror EP in the article.In the part of overall design of the Virtual Classroom (Chapter four), this article uses the Object Oriented technology to build the Virtual Classroom system. And the implementation of classroom controller server software, teacher client software,...