面向全局约束的QoS分解与服务状态监控机制研究

组合服务QoS需求的全局性和服务QoS状态监控的局部性之间的矛盾使得组合服务的可用性难以满足用户的需求.针对此问题,提出了组合服务的自适应框架,重点研究了全局QoS分配与服务的QoS状态监控机制;通过分析服务的QoS历史信息来预测服务的QoS阈值,从而为全局QoS分解提供启发信息.并引入松弛系数以降低服务自适应的开销.实验表明:通过QoS阈值预测和松弛系数的使用能够实现以较小的自适应开销适应环境变化满足用户端到端的QoS需求,从而提高组合服务的可用性.

Research on QoS Disco mposing and Service Status Monitor for Co mposite Service with Global QoS Constraint

Contradiction between the global QoS requirements and local service QoS status monitor decreases the a-vailability of composite service,and makes it hard to meet users’requirements.Aiming at this problem,a framework for composite service adaption is proposed.And the mechanism for composite services QoS decomposing and individual service status monitor in this framework is demonstrated.To get the threshold of individual service,an approach to predict the serv-ice QoS by analyzing the historical QoS is studied.Further,to decrease the overhead of composite service adaption,the relax index is introduced into the mechanism.The experimental results show that predicting the QoS threshold and relax index can make the composite service QoS decomposing more reasonable,and can satisfy the user’s end-to-end requirement through little adjustment to the greatest extent when changes happen.