Research On Key Technologies Of Web Service Dynamic Composition

The Internet is now undergoing an evolution from a simple platform for information sharing to an open distributed computing infrastructure. With more and more data resources, computing resources and applications accessible via the Internet for public usage, resource sharing and application integration across organizational boundaries have been recognized as comprehensive requirements in many domains. In recent years, the concept of service has been proposed as a mean of abstracting and wrapping diverse resources in open environment, which makes service composition the natural way for dynamic resource aggregation and flexible application integration. Especially, along with the prosperity and acceptance of Web Services as the mainstream technology for service provision, dynamic service composition based on Web Services has been regarded as one of the core technologies for the service-oriented computing paradigm, and consequently a hot research topic in the area of distributed computing.To address the requirements of inter-organizational resource sharing and application integration in open computing environment, we have investigated some important issues of dynamic service composition. The contributions of this dissertation are as follows:(1) Computing framework for dynamic service composition. We investigate the character of service-oriented computing environment and the developing process of composite service. With the common supporting functions for composite service applications resolved, the Dynamic Service Composition Reference Model is proposed.(2) Business process based composite service model analysis theory and methods. Runtime correctness of composite services is closely related to the correctness of composite service model. In this dissertation we have modeled composite service as business process and proposed a high-level Petri net, namely Process-Net, to model, analyze and verify the control flow and data flow behavior of composite service. The behavior correctness of composite service is defined by the process behavior correctness and composition compatibility. Based on Petri net theory, we study the typical behavior problem related to control flow and data flow, and introduce the concept of soundness of Process-Net as the formalized criteria for process behavior correctness.