Abstract: To implement uncertain QoS-aware Web service selection under the circumstance of the deficiency of user's precise utility function and the unknown of QoS probability distribution forms,an admissible composition plans based on stochastic dominance theory was proposed to discover the function class which were compatible with the user utility.According to the expected utility theory,the admissible composition plans could not be dominated by any others.By eliminating the services or intermediate composition plans which were included in the admissible set,the search space in finding the admissible set was significantly reduced.Moreover,a heap-based composition plan extracting and expanding process was developed based on the properties of stochastic dominance,so that the numbers of stochastic dominance tests were reduced.The effectiveness and efficiency of the proposed method were verified by theoretical analysis and comprehensive experimental research based on real datasets of Web service QoS.

Key words: Web services, uncertain quality of service, stochastic dominance, admissible composition plans, Skyline services

摘要： 为在缺乏用户精确效用函数且服务质量分布形式未知的情况下实现不确定服务质量感知的Web服务选择,提出了基于随机优势理论计算符合用户效用函数类别的可行组合方案的方法。按照期望效用理论,可行组合方案不会被其他任何方案占优。通过剔除不可能出现在可行组合方案集中的候选服务以及中间组合方案,有效降低了候选组合方案的数量。利用随机优势的性质,通过堆结构对组合方案进行提取和扩展,减少了随机优势测试次数。通过理论分析和基于真实Web服务服务质量数据的实验结果,验证了所提方法的实用性和有效性。

关键词: Web服务, 随机服务质量, 随机优势, 可行组合方案, Skyline服务