云计算以用户为中心按需提供服务,云环境下必须关注用户的服务质量(QoS).云计算工作流调度的QoS目标约束条件,不仅有工作流完成时间,还包括调度预算、系统的可靠性以及安全性等,多维QoS约束的工作流调度算法的研究至关重要.为此,提出一种基于生物共生演算法(symbiotic organisms search,SOS)的多维QoS约束的工作流调度算法(QoS-SOS).首先为工作流中的每个任务分配适当的优先级,将非支配解的思想融入到生物共生演算法中,从而获得分布均匀的Pareto最优解集来解决多维QoS约束的工作流调度问题.实验结果表明, QoS-SOS不仅拥有较快的收敛速度,而且有很好的寻优能力,还能够根据用户的偏好选择侧重不同的优化方案,从而适应于大规模的云环境.%As cloud computing provided user-centered and on-demand services, the quality of service (QoS) must be concerned in the cloud environment.Not only the execution time of the workflow but also scheduling budget, system reliability and security, etc.were included in the objective constrained QoS of cloud workflow scheduling.The study of the workflow scheduling algorithm based on multi-QoS constraints became a matter of indispensable role.A workflow scheduling algorithm based on symbiotic organisms search for multidimensional QoS constraints was proposed.Firstly, priorities were assigned for each task appropriately in the workflow.The concept of non-dominated solution was incorporated into the symbiotic organisms search algorithm.The uniformly distributed Pareto optimal solution set could be obtained to solve the problem of workflow scheduling problem with multi-QoS constraints.The experimental results showed that the QoS-SOS not only had faster convergence rate and an excellent optimization ability, but also could get different optimization schemes based on the user's preferences, which could be adapted to the large-scale cloud environment.
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