一种面向多用户的负载感知动态服务选择模型*

摘要

在面向多用户的动态环境中进行基于QoS的服务选择需要面临诸多挑战,而动态的服务负载就是其中之一。当前的服务选择方法难以在多用户多业务的开放环境下应对服务执行时的负载动态变化,缺乏实时感知负载的应变能力。针对这一问题,首先,提出一种基于负载等级的服务多维QoS模型(load level based multidimensional QoS,简称 LLBMQoS)；在此基础上,提出了一种面向多用户的负载感知的动态服务选择模型(load-aware dynamic service selection model,简称LADSSM)以实现动态负载环境下的服务优化选择。该模型采用两阶段服务选择：在组合服务规划阶段,生成候选服务队列；在组合服务执行阶段,依据当前负载状态实现服务的动态选择；最后,仿真实验的结果表明：该模型较好地适应了多用户动态环境下的服务负载变化,能够在保证用户端到端QoS需求的前提下,及时而有效地提供效用优化的服务选择方案。%There are many challenges associated with service selection in a multi-user, dynamic environment. One of these challenges is the frequently changing workload. Traditional approaches to service selection, however, don’t adapt to the frequently changing workload in the open and multi-user environment and can’t deal with the varied workload in real time. This study is to address the problem, First, a load level based multidimensional QoS model (LLBMQoS) for services is presented;Next, a load aware dynamic service selection model (LADSSM) is proposed based on LLBMQoS to optimize service selection in dynamic environments. The model adopts a two-phase service selection framework, which generates candidate queues in design time and dynamically selects the services in terms of the current workload in execution time. Finally, simulation experiment results are provided to show the proposed model can adapt to the varied workload in a multi-user environment and provide an optimal service selection scheme while meeting the end-to-end QoS constraints.