Abstract: To meet the urgent demand for Web service compositions in temporal constraints, a compatibility and modification method of service composition based on Finite State Automaton(FSA)was proposed. According to temporal constraints of FSA model and time information of internal activities, the possible time of service composition was derived. The composition possibility analysis was used for activities with external composition time to verify the temporal compatibility of service composition. Aiming at the partly compatible service compositions, a corresponding temporal compatibility modification technique was proposed. The effectiveness of methodology was validated through a real-life case. Compared with the existing approaches in this field, the proposed method could effectively avoid the severe problem of state explosion, which was more intuitive, practical and reusable.

Key words: temporal constraint, Web services, temporal compatibility, modification

摘要： 针对时序约束情况下Web服务组合的迫切需求，提出一种基于有限状态自动机的服务组合兼容性分析及修正方法。该方法首先根据组合有限状态自动机模型中的时序约束及内部活动的时间信息，推导服务组合的可能时间；然后对带有外部组合时间的活动进行组合可能性分析，基于活动的组合可能性验证服务组合的时序兼容性；针对时序部分兼容的服务组合，提出相应的时序兼容性修正方法。通过实例验证了该方法的有效性。与现有方法相比，该方法能够有效避免状态爆炸问题，且具有直观、实用性强、可重用性好等优点。

关键词: 时序约束, Web服务, 时序兼容性, 修正