The Research On Key Technologies Of Dynamic Web Service 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, such as commerce, scientific research, military area and etc.. 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.Many research institutions home and abroad have conducted quite a few researches on dynamic service composition, and have made some valuable achievements. However, the computing framework, modeling theory, implementation mechanism and other key technologies related to dynamic service composition are not well developed. New issues keep emerging.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 and done comprehensive work in this dissertation to improve its correctness, flexibility and efficiency. We start our research from the general computing framework of dynamic service composition, and focus on the following key technologies: model analysis theory and methods for composite services, composition plan selection algorithm based on quality of service (QoS) and highly efficient composition coordination mechanism. 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 (abbreviated as DEMO) is proposed. DEMO adopts three-layered architecture for composite service application system which includes the composite application layer, the service composition supporting platform and the web service infrastructure layer. Also DEMO partitions the service composition supporting platform into four inter-dependent modules according to composite service lifecycle. By doing so, DEMO provides a reference framework for dynamic service composition technology researches, service composition supporting platform construction and composite service application development.