基于天地网的同步实时授课系统研究

Research on synchronizing and real time lecturing system based on TV satellite and computers

针对现有实时授课系统存在的规模小、可扩展性差等方面的问题,本文作者提出了一种基于卫星和地面计算机网相结合的天地网平台之上的同步实时授课系统SkyClass的实现方法。该系统采用卫星链路实现教学现场的直播,采用地面IP网实现师生间多模式的交互。本文对系统的网络模型以及卫星链路中教学现场传输的QoS控制问题进行了论述。目前,SkyClass已在国内得到了有效的应用。

Real time lecturing is the most important part of multi-media distance education.Its application can realize live-transmission of the on-the-spot teaching and solve the problem of restriction in time and space of traditional classroom teaching.Therefore,it can expand the scale of teaching and makes it possible to share teaching resources.The author of this article addresses such issues as the small scale and poor extension of the existing real time lecturing system,he offers the readers with a picture of combining satellite and internet to construct a connected and communicative platform and based on it a synchronizing and real time lecturing system,SkyClass,is constructed.This system adopts satellite linking route to realize on-the-spot teaching and use IP network on the earth to realize multiple modes of interaction between students and tutors.`This article makes analysis on the on-line model of SkyClass,introduces some key know-how solutions as grade-entrance control,method of bandwidth distribution,control of service quality and errors,etc.It narrates particularly on the controlling issues of Qos transmitted through on-the-spot teaching in the satellite linking route.At last,the author makes a brief introduction of SkyClass system's extensive and effective application in some places like Xijiang,Shannxi,Shanxi,and Henan.