Web服务组合中行为兼容性分析与优化控制策略

摘要

针对Web服务组合中交互行为不兼容问题,本文提出了基于Petri网的优化控制策略来规避.首先,给出了多个服务交互行为不兼容的实例.其次,给出了受控服务组合的形式化定义,并根据约减规则生成了约减的服务组合网状态可达图,从而识别出死锁状态和无死锁状态.在导致死锁状态的关键变迁上添加相应的控制库所和弧,并结合最大允许反馈控制策略,从而推导出最优控制器,并证明了该方法的正确性.此外,通过服务组合中交互行为不兼容的实例证实了基于最优控制器策略的有效性.最后,本文将最优控制器模型转换成BPEL.%A Petri net based optimal control policy is proposed for the check of behavioral incompatibility in web services composition. According to a real case of multiple services interaction, this paper presents a formalized definition of controlled service composition, and the reduced state reachability graph of service composition net is given according to the reduce rules, thus the deadlock states and the deadlock-free states are identified. With the maximally permissive feedback control strategy developed, the appropriate control place and arc are appended in the key transition which can lead to deadlock states.Thus the appropriate optimal controller is developed,the proposed approach is verified. In addition,for the behavioral incompatibility case,a policy of appending optimal controller is presented. It is proved that our policy can be a good solution.Finally,the proposed controller is transformed as the activity of BPEL.