Research On The Method Of Credible Web Service Composition Based On Petri Net

Web service is becoming an emerging Internet application mode, due to the complexity and dynamic of the users’demands, and the openness of the application environment and the uncertainty, a single service can not meet the needs of complex applications. Only from the function perspective has been unable to cope with rapid changes of environment and demands during the service composition. Therefore, how to achieve the credible services composition under the behavior constraints to meet the demands with high quality, it has important significance for the reuse of the network resources and collaborative.At present, the Web services composition focuses on two aspects:function perspective and the services behavior perspective. It has a poor considering in the behavior constraint processing, and there are certain limitations to determine the behavior consistency, which may lead to generate the change domains. This paper, from the credible service behavior perspective, mainly studies the following three contents:(1) This paper, we propose the analysis method of credible Web service composition based on behavioral patterns. The credibility of composite services is mainly reflected in the function demand and behavioral perspective after composite. The function demand of composite services can be achieved through the effective composite, and it is easy to implement. However, due to the interaction between the components or external factors in the combination process, it will produce some unexpected behaviors. Therefore, it is not only to determine the soundness, but also to analyze the predictability of behavior. For the problem that whether the components is the right composition and the relationship of interaction is difficult to determine between components, we propose the action patterns based on Petri nets in this paper, the behavioral profile captures the constraint relationship of activity transitions and action patterns requirement for some event occurrences to capture the behavior relationships between the service components, then achieve the interaction of predictability composition. The method can prevent the undesirable or wrong interactive behavior between services by the label information on the activity transitions, and achieve the predictable behavior analysis of Web service composition.(2) Put forward the model consistency analysis method that integrate the relationship of data flow and control flow. The research of the behavior credibility of Web service composition that its core is the behavior consistency analysis of composite service models. The existing studies mainly analyzed the models consistency from the control behavior perspective, ignoring the role of the data flow, which result in can not properly analyze the credibility of some Web service compositions. In this paper, we use Petri net to research the business process control flow and data flow representation, and the behavior dependencies of the sequence of activities, then propose a behavior consistency analysis method with data flow and control flow based on Petri network behavioral profile. The method fully considers the role of data flow in models’ behavior consistency analysis.(3) The analysis method of locating change domain in the business process model has been proposed based on Petri net and behavioral profile. For incredible problem arising from the Web service composition, the main task is to locate the change domain in the business process model, in order to adapter and modulation. For the research of change domain, the exiting proposed methods are to search the change domain by a given node on the basis of static analysis, which had some limitations. In this paper, according to Petri nets and behavioral profile to analyze business process models, give a dynamic analysis method to locate change domain, and the optimization method. Theoretical and example analysis show that the method is effective.