Research On Adaptation Mechanismand Methods For Service Coordination

As brand new computation paradigm and system architecture, Service-Oriented Computing (SOC) and Service-Oriented Architecture (SOA) begin to change the software industry and information technology. They have made a profound impact on the software design and development. As Web service related industry standards and products begin to emerge, the transformation of SOC from concept to reality is underway.SOC uses services as the basic building blocks of application development. Through service reuse, new distributed systems are created. Consequently, the key to SOC practice is making sure the interoperability among services. But since the requirement of a service is relatively stable, it cannot deal with its ever changing environment. Thus, incompatibilities among services are becoming overwhelming. Study service adaptation technique and ensure the interoperability among deferent services has become a pressing concern when practicing SOC.We start from the signature and behavior level of web services, study the (semi-)automatic adaptation methods. The main work and contributions of this paper includes tlte; following4aspects.First, we study the signature level adaptation technique and propose an ontology alignment based adaptation method. Web service signature describes the basic invocation information, such as data types, variable names, etc. We make use of the semantic web technology and propose an efficient sub-ontology extraction method. This method significantly improves the ontology alignment result between deferent ontologies. Experiments are conducted to verify the efficiency and accuracy of this method.Secondly, we propose a linear logic based behavior model and compatibility verification and computation method. Web service processes can deal with more complex events and satisfy more demanding business requirements. The behavior of a service process refers to the order of messages, in which they are sent and expected by this service. We’ve developed a method to convert WS-BPEL processes into linear logic expressions to better serve the needs of service compatibility verification and behavior adaptation. We’ve also improved the scenario, in which behaviour compatibility is defined and verified, and presented the methods for compatibility degree computation.Thirdly, we propose an automated service process adaptation method based on linear logic theorom proving. Due to the loosly coupled nature of SOA, the deferences among the order of messages may cause behavour mismatches. We ultilize the deducation power of linear logic and define adaptation specification and adaptation target, which specify the ablitiy of the adapter and the functional and non-functional constraints of the adaptation process. We propose the use of backgournd services to resovle deadlocks between service processes, which are currently considered as unsolvable by automated method. We’ve also proposed an intergration of Pi calculus and linear logic to achieve direct extraction of adapters for linear logic solutions.Last, propose a system framework for service adaptation, WSAF, and its prototype implementation. WSAF describes all the mandatory components and their functions. With integration to the enterprise service bus, JTangSyngergy, we have implemented a prototype for WSAF.