Conformance Checking and QoS Optimizing of Web Service Composition

Due to the inherent autonomy and heterogeneity of component Web services it is difficult to predict the behavior of the overall composite service. Besides, the performance of the composed application is determined by the performance of the involved component web services. Therefore, the behavior conformance and non-functional quality of service (QoS) properties are crucial for selecting the web services to take part in the composition. The behavior conformance of component services is the guarantee of the correctness of Web service composition, and QoS properties can identify the best candidate web services from a set of functionally-equivalent services. In this paper, two formal judgmental rules are presented, which check conformance of local behavior of every component service to global interaction. We also use skyline computation to select services for composition effectively and efficiently, reducing the number of candidate services to be considered. We also define aggregation functions, and use a Multiple Attribute Decision Making approach for the utility function to achieve Qos-based optimal service selection. We evaluate our approach experimentally using both real and synthetically generated datasets.