Abstract: For the functional superposition of large numbers of Web services that emerges in the Internet, QoS attribute should be considered to solve the service selection problem of Web services composition. It’s too strict to express QoS by basing range in the traditional way. So here, users can express their QoS preference more flexibly through importing fuzzy set to describe the QoS requirement; the generating execution plan can promote the users’ satisfaction in the largest degree through mapping the Web services dynamic problem to FCSP. The paper’s emphasis is the implementation of the Web service dynamic composition algorithm and the data analysis of experiment result. The result shows that the algorithm can produce a satisfied execution plan in less time.

Key words: QoS; Fuzzy constraint satisfaction; Web Service; Dynamic selection

摘要： 针对网络中发布的众多Web 服务存在功能上的重叠性，需要通过其QoS 属性来解决组合Web 服务中的服务选择问题。传统的基于范围的QoS 表示方式过于严格。该文通过引入模糊表达式对QoS 属性的需求进行描述，使用户对QoS 的需求描述更加灵活；通过把基于QoS 的Web 服务动态集成问题转化为FCSP，使产生的执行计划解决方案可以最大限度地提高用户的满意度。重点介绍了基于FCSP 的Web 服务动态集成算法的具体实现以及实验结果的数据分析。结果显示，算法能在较短的时间内产生令人满意的执行计划。

关键词: QoS；模糊约束满足；Web 服务；动态选择