Research On Task-driven Dynamic Service Integration Mechanism In Pervasive Computing

In task-driven pervasive computing, software and hardware resources can be fully scheduled and integrated to form available services, and effective implementation of user task is given the first priority. As the services in pervasive system are featured by heterogeneity, resource-limitation and mobility, pervasive computing environment is characterized by dynamism, which brings uncertainties to the fullfillment of user tasks. Consequently, task-driven dynamic service integration mechanism has become an indispensible aspect of pervasive computing.The paper mainly focuses on the task-driven user task and researches on service integration mechanism with aspects to dynamism in pervasive computing environment. Task-driven hierarchy, model analysis of dynamic service, service integration of task-driven and middleware mechanism of service integration are discussed to present a effective mechanism for service integration and a useful method for user task execution in dynamic pervasive computing environment.(1) From the perspective of task driving, the attributes and hierarchy of task are analyzed to give a detailed description of context-aware active task model. A task-driven hierarchy is designed with a clear explaination of each layer. The paper researches on task-driven integration mechanism and specifies on activenesss anaylsis, attribute association, active execuation of task.(2) In the process of modeling and analyzing dynamic service, architecture of dynamic service system, modeling of dynamic system, centralized dynamic service, distributed dynamic service and comprehensive analysis of dynamic service are discussed to demonstrate the basic concepts in dynamic services. A solution for the aggregation and decomposition of dynamic services in pervasive computing environment is put forward.(3) On the basis of task-driven service integration mechanism, effective solutions and implementations are presented. A session based service access mechanism is put forward with task-driven service transformation and session based access control mechanism. Task-driven service management architecture is designed on the basis of context modeling, ontology design and classification. And then a context-aware service management mechanism is presented. Furthermore, with aspect to the features of task-driven, service discovery framework, service discovery query and service discovery process are discussed to specify the task-driven service discovery mechanism and the relevant solution is designed. Finally, rough set theory and genetic algorithm are applied to realize dynamic service matchmaking and multi-task multi-service allocation. The experiment result shows that the algorithm is feasible and reasonable.(4) Above all, middleware requirements in pervasive computing environment are analyzed and some key issues in middleware applications are discussed. A task-driven pervasive computing middleware model and architecture are presented. Moreover, the functionalities of each component are clarified to explain the task-driven service integration strategy and the validity of the architecture is discussed.