Research On P2P-based Virtual Classroom Of Oral Communication

There is an increasing demand in graduates' English capabilities especially the spoken English capability along with the development of China. However, owing to the shortage of English faculty and uptight budget, most teachers have to handle around 50 students in oral English classroom, which makes it impossible to offer students time and opportunities to speak, let alone to effectively improve their communicative skills through oral tasks. Web-based education is featured with large information, high transmission speed, and being free from the limit of time and location, and hence has become the main approach to the issue.At present, most real-time distance education systems employ a central means using multimedia broadcast or video/ audio conferencing to mainly realize formal lectures, physical experiments or collaborative environment. Those systems, besides the shortage of low scalability and potential danger of single node failure, are either lacking in interaction or quite expensive for realizing high interaction with peculiar equipments. The thesis is mainly focused on designing a large scaled, highly interactive virtual classroom tailored to oral communication using Application Layer Multicast (ALM) in a Peer-to-Peer (P2P) network. And its work is of significance to highly interactive applications like large scaled audio conferencing and multiparty games.Following is the main work of the thesis:(1) The suitable teaching modes and interaction types for virtual classroom of oral communication are put forward. The thesis studied characteristics of face-to-face oral English teaching, analyzed the main teaching modes in web-based education in the perspective of technology applied and interaction, compared schemes in realizing web-based oral English teaching and concluded that the P2P-based ALM is the suitable technique for web-based oral English teaching to provide low-delay and interactive realtime audio group communication.(2) Foundamental techniques in realizing interactive ALM are discussed. Those techniques include resource lookup and low delay group session management. Works on those two issues are studied. Suitable approaches are selected to realize the virtual classroom of oral communication.(3) A Kademlia-based realization of P2P audio transmission is proprosed as a basic module in virtual oral communication classroom. To realize the lookup of resource, and of nodes in particular, the thesis analyzed Kademia and its realization in eMule.(4) GIM, a gossip-based ALM strategy is proposed tailored to virtual oral communication classroom. And simulation results are provided to prove its efficiency.(5) A P2P-based oral English classroom is designed based on the mentioned efforts. The thesis stated its basic infrastructure and role function, introduced its main communication mechanism and the evaluation module of the exercises done by students.