中文摘要：

服务选择问题是服务组合中的一个关键问题，尤其在服务选择时应充分考虑服务质量因素。该文研究了基于用户服务质量需求的服务选择方法，通过对各项QoS（qualityofservice）因素分别加权，将面向用户服务质量需求的服务选择问题转化成单目标优化问题。在充分考虑服务实际质量和用户主观需求的基础上，给出了QoS组合权重的计算模型；并在候选服务集的基础上，依据用户的服务质量需求，定义了用户满意度函数，进一步利用遗传算法解决服务选择问题。实验结果表明，文中提出方法具有明确的用户需求指向性和选择灵活性，能够最大程度上满足用户需求。

英文摘要：

Service selection is a key issue in service composition, and the quality of service should be taken full account of,especially. As to service selection oriented to user QoS requirements, a method is given to transform it into a single objective optimization problem by weighting each QoS factor. Considering both actual quality of service and users＇ preferences,propose a combination weight computing model;also, according to users＇ QoS requirements, define the concept of degree of users＇ satisfaction, further by using the genetic algo rithm to solve service selection problem. The method is proved to be more effective in meeting users＂ requirements,both on demand direc tivitv and dynamic selecting flexibility.