基于动态QoS的Web服务组合

Composition of Web Services Based on Dynamic QoS

在Web服务组合中,现行的几种QoS衡量标准都将重点放在单个Web服务本身的质量上,而忽视了Web服务动态特性、组合特性以及服务组合中的网络特性。另外,在诸多服务组合的算法中,都只是强调组合服务的总体质量,却忽略了用户对某些质量属性的约束条件,从而导致服务重计算问题经常发生。为此,考虑了服务动态特性以及服务间的协作关系对组合服务质量的影响,提出了动态QoS模型;同时,综合了用户的质量约束以及组合服务的整体质量,将用户的质量约束引入服务组合流程中。最后通过实验证实了所提出的动态QoS模型能够根据服务实体的实时情况计算服务质量,同时将用户的质量约束引入服务组合流程中,有效地避免了服务重计算问题。

In composition of Web services,several current standards of QoS focus on the quality of independent Web services,and ignore the dynamic,compositional,network-savvy characteristics of Web services.In addition,many combination algorithms emphasize the overall quality of compositional services and ignore the constraint conditions of users.This results in the recalculation of composition of Web services.Therefore,considering the dynamic characteristics of the service and the efforts of collaboration between the services,the author put forward a dynamic standard of QoS.At the same time,the author also took into account the constraint conditions of users and the overall quality of compositional services and applied the constraint conditions of users in the composition process.Finally,we proved that the dynamic QoS standard can compute the real service quality of service entity and that applying the constraint conditions of users in the composition process can avoid the service re-computing effectively.