The Research On Service Composition In Service-Oriented Computing

With the rapid development of the open distributed computing, middleware technology has evolved from the stage of Object-Oriented Computing to that of Service-Oriented Computing. SOC is much more close to the business logic of application layer and has features of agility and dynamic-adaption. It can be associated with Model Driven Architecture to form a more flexible manner of constructing applications. The whole concept of SOC is coming into being as it developed. As a feature of SOC, Service-Oriented Architecture plays an important role in the implementation of service computing style application. The three-part model is not an innovative contribution of SOA, but which causes the concept of using services to achieve a success that have not reached before. SOC has formed its own particular modeling and developing languages. Being different from OOC, most of those modeling and developing languages focus on workflows in connection with business processes. SOC also has various development frameworks and environments that make its implementation can be completed according to standard and also done visually.There are many new problems for SOC to be solved. Among them, how to compose a coarse granularity service for business logic from some fine granularity services is the most fundamental one. There are many methods for composing services and the most popular one of them is to use the process description languages in connection with workflow. In order to guarantee the correctness of services composition, many formal and informal methods are applied to describing and verifying of those compositions. The one based on process and another based on semantic web are usually used. Many formal methods such as Petri-Net and process algebra may be used as the basis of the method based on processes. The process algebra method is more suitable for describing services composition because of its composite feature. The pi calculus in process algebra is a better formal method to describe mobile concurrency system and to model dynamic service system. In this paper, the solutions for the formal modeling and verifying service composition are discussed in theory and practice. The main works done by the author are listed below:1. Analyzing the formal method basis of service composition and selecting the pi calculus as the modeling tool. 2. The mapping relation of service composition languages and pi calculus is studied and the rules and procedures to model service composition are proposed.3. After explaining the concept of consistency, for which pi calculus is used as the formal method basis and how to guarantee the consistency is illustrated.4. Service compatibility and substitution are studied and their existences are verified by pi calculus.5. PiFF—a formal framework for service composition is proposed and the method to integrating it into service computing platform-UESTC-PLATFORM is studied.