Wireless Ad Hoc Combination Of Technology In The Organization's Network Study

The advances in mobile devices and wireless communication technology have enabled a new type of network:ad hoc network (MANETs). In ad hoc network, all nodes can move randomly, the network topology changes dynamically, and nodes communicate with each other through miti-hop cooperation. As a special wireless network without fixed network infrastructure, it has extensive application prospect in military and civilian field.Service composition satisfies user's complex request by combining several atomic services into a more complex one. Traditionally the research of service composition mostly focus on the wired network, which adopts agents to administrate service discovery, service composition and service execution. With the development of wireless communication technology, the service composition in ad hoc network is starting to be paid attention to.Focusing on service composition in ad hoc network, we did the following work:Firstly, we proposed two execution path discovering approaches. In ad hoc networks, the first step for the execution of composite service is to find an effective execution path, in other words, to select atomic service providers as well as an achievable scheme for composing service. However, existing solutions fail to consider the overhead incurred by exploring the execution path and the condition of service execution. In this paper, we present two execution path discovering approaches in ad hoc networks, which constrain the range of execution path discovery under the precondition of ensuring an acceptable success rate of discovering execution path. Our methods reduce the network traffic and avoid discovering useless execution path to a great extent.Secondly, we studied the strategies for service selection and fault recovery. On the one hand, after finding the service composite scheme in the current network by composite service discovery, the next course of service execution is to do the service selection which will directly affect the efficiency of service execution.. Based on the QoS'preference, we discussed three different factors including the lowest energy consumption, the shortest network response time, and the lowest failure rate of network transmission. Then we proposed a multi-dimensional service selection strategy for integrating these three factors together. On the other hand, the services may fail in the execution process, so some kind of mechanism to restore those services in failure should be brought in. Considering the high failure rate of service execution in ad hoc networks, we suggested the fault recovery strategy to assure an effective implementation of services. Finally, we implemented execution path discovering approaches proposed above, and the simulation results proved that our approaches effectively decrease the amount of execution path discovering packet delivered, and reduce the traffic load.