Research On Event-based Service Coordination And Communication Service Provision Technology

There are two important characteristics in the development of current network and service technology. The first one is the smart network represented by Ubiquitous Computing and the Internet of Things, with static sensing devices, mobile and wearable devices as well as common Internet service served as the main means of obtaining informations and service provision. The smart services should be capable of situation sensing and intelligent coordination so as to suit the new dynamic and flexible network environments. The second characteristic is that the convergence between Telecom and data network has expanded the business types of communication services, and an effective way is needed to support the low-lantency communication services in hybrid Telecom/IT service environment. In this dissertation, the event mechanism, whose main characteristics are loosely-coupled, asynchronous as well as real-time enabled, is introduced in traditional service computing technology. Aiming at the service coordination and real-time communication service provision problems, the main contributions of the dissertation are as follows:Fristly, the dissertation presents a coordinated service process model based on events, which serves as the theoretical and conceptual foundation of service coordination. The model targets at service coordination driven by active service processes and provides a basic framework for loose coupling, heterogeneous and asynchronous interoperation among smart services. The framework also supports the sensing problem during service collaboration as well as analyzing data from multiple sources.Secondly, in light of that current event specification languages have limitations when expressing complex coordinated service situations, the dissertation presents ECSSL, an event based situation specification language. Treating the informations from environment monitoring as events, ECSSL can define complex event patterns with a simple syntax and a formal temporal logic, as well as offering fully customizable policies for event selection and consumption. The dissertation applys ECSSL in two sample scenes:a coal mine gas alert situation and an intelligent logistic situation. It ends by giving an automata based situation detection algorithm, which can effectively interprete ECSSL.Thirdly, the dissertation proposes the behavioral model of event-driven service coordination in smart service environment. The behavioral model, which is based on ECA triggering, can enable global orchestration as well as local choreography of collaborative services. Since general ECA rules have limitations in expressing coordinated service control flows, the dissertation presents an enhanced ECA for flow control. To facilitate the coordination behavioral, the dissertation proposes a collaborative process decomposing algorithm. The algorithm transforms the global process model into a set of local process and event flow models, which finally leads to a set of ECA rules. These rules depicits a coordinated execution sequence which realizes the event-driven active coordination of a collaborative process. Besides, the dissertation presents a design-time rule mismatch detection algorithm, which ensures the action constrains based service coordination.Finally, the dissertation presents an event-driven communication Web service provision approach, which overcomes the limitations current approaches. The approach first seamless integrates the low-latency service engine EDLE into a hybrid service bus. Then, to construct communication services, the dissertation analyses the characteristics of EDLE and summarizes the basic service construction model as well as related attributes, which establishes a theoretical basis for event-driven communication Web service. The dissertation implements the multimedia conference prototype and conducts some simulations, whose results show that our event-driven communication service provision approach serves reliably and efficiently, and the running of constructed communication Web services meets the real-time requirement of Telecom domain, which should have a good application prospect.