Pervasive Computing Environment In The Context Of Perceived Calculated

The third generation computing model-Pervasive Computing is the ultimate goal of the existence of computers,and it is also the direction of the development of computers.According to the understanding of the concept of pervasive computing and the intruduction of the context model,this thesis establishs the context model and proposes the concept of the P2P network service domain,and it does initial reseach about the registration,inquiry and composition in the service domain.Pervasive computing is the result of the rapid development of modern computer technology.With the development of computers,computing model has experieced mainframe computing,desktop computing,and ultimately it is developing in the direction of Pervasive Computing.Pervasive Computing is people-oriented, people-centered,which is ultimate goal of the invention and use computer-the computer is ubiquitous,easy-to-use and transparent;its autonomy,self-perception to aware the people's needs;Pervasive Computing serves people accurately to make people escape from the shackles of computer technology and the embarrassing situation in front of the computer,makes computer operation and use to be simple and convenient.This thesis first discusses the concept of pervasive computing context and the classification of context.This thesis presents a service-based model and the context of the service-oriented domain based on the understanding of the context,and discusses the context model of the work method and condition.This thesis presents services domain which based on the P2P network model.P2P networks are product of peer to peer computing concept and its core is all of the network nodes which are interconnected equally and cancel the existence of the server.So P2P concept is apropriate to pervasive computing.Because in the concept of pervasive computing,people use computing equipments inadvertently,wherever the people are,they can use "transparent" computing devices,so all the computing equipments must be equal in the concept.Otherwise,if the existing network in the environment in which people do not have a server or the server is busy,people will not be able to access every possible way computing services.Therefore,services domain is constructed on the P2P network in this thesis. To facilitate the discussion services domain,this thesis ignores the service node mobility,and usese unstructured Gnutella P2P model within service domain and applys Pastry model in remote access,which is not contradictory,it just views the issue from different perspective.Based on unstructured P2P model,the register run by the super-nodes,it can not only effectively exert the advantages of a stronger ability nodes,but also ensure the stability and fault-tolerance of P2P mode.Register is the carder for services register and enquiry,this thesis presents the most optimal way useing system engineering point of view.The Minkovski distance or Euclidean distance for parameter is used to enquiries and expanded to more goals enquiry method.The last part of this thesis presents the service composition,the service composition is used when service can not match require in thr service domain,the existing services are by type of service and input/output data type matching to compose,which it has resolved the failure of situation which is a long-range enquiry or visit.In the services domain network,the redundant mechanisms is used to effectively improve the reliability and efficiency of service composition,and it is effective for dynamic system.