关键词: 服务组合, 可信演化, 信息熵, 服务选取, 服务质量

Abstract: In addition to the dynamic of service’ generation and died，the quality differences between provided services，there are a mass of malicious，camouflage，false untrue services in the Internet.As result of that，it is difficult for client to get fast and high-quality services.In this paper，a service-composition framework based on the trust evolution and trust alliance has been proposed.It is different from traditional service-composition model.The trust relationship will be built after the trust evolution between service requester and provider.The trust service requester and provider is going to form a alliance through the relationship，so the malicious，false services will be excluded from the system and the service-composition is carried out in a trust system.On this basis，a services selection algorithm based on credit evolution and alliance is put forward，avoiding the deficiencies of multi-dimensional trust indicators simply weighted in the previous studies.Theoretical analysis and experimental comparison confirm that the framework proposed in this paper has a better ability to organize services，so as to make higher-quality，faster combination of services.

Key words: services composition, trust evolution, information entropy, services selection, Quality of Services