So it is very important and useful to research the VOD system structure and the request schedule algorithm on it. 因此，研究视频点播系统的体系结构及其请求调度策略，具有相当重要的意义以及非常大的实际应用价值。
The dynamic and heterogeneous nature of grid resources is a great challenge to static scheduling strategies of dependent tasks. 摘要网格资源环境的动态性和异构性对依赖任务的静态调度策略产生了极大的挑战。
