中文摘要：

提出了一种基于贪心策略的启发式任务调度算法,用于优化云计算环境下任务调度中执行时间。首先,给出了云计算环境下任务调度问题的形式化描述及其最早完成时间的启发式优先分配原则;接着,基于最早完成时间的优先分配原则,采用贪心策略难易交错地分配任务求得任务调度的初始解;进而,引入了任务对交换的收益值概念,采用贪心策略选择收益值大的任务对交换优化任务调度初始解的执行时间;最后,在Cloud Sim云计算仿真实验平台下进行了顺序调度算法、Min-Min算法、Max-Min算法和本文算法的对比实验,实验数据对比充分验证了本文算法既能减少任务执行时间,又能使资源负载相对平衡。

英文摘要：

We propose the heuristic task scheduling algorithm based on greedy strategy in cloud computing to optimize the finish time of whole tasks. Firstly, the formal description of task scheduling problem in cloud computing is presented. We also present the heuristic principle of the earliest finish time（EFT） for task scheduling. Furthermore, the initial solution steps of task scheduling based on the EFT principle and the greedy strategy are given. Then, we propose the gain of task swap and adopt the greedy strategy to swap tasks to improve the task completing time of the initial solution. Finally, we carry out the comparative experiments among the sequential scheduling algorithm, Min-Min algorithm, Max-Min algorithm and the proposed algorithm based on Cloud Sim simulation platform of cloud computing. The experiment and analysis show the proposed algorithm has better performance in terms of the decreasing the task completing time and the improvement of resource load balancing.