Research On Multi-Queries System Framework And Aggregation Techniques In Distributed Sensor Database

Wireless sensor networks (WSNs), a novel network, which integrated with micro-electronics technology, computer technology and wireless communication technology, provide a new approach to information acquisition and processing. It consists of a large number of small sensor nodes and accomplishes distributed query tasks through wireless communication collaboration among them. In recent years, it is extensively applied in military and national defense, biomedical, environmental monitoring, emergency relief, and many other important areas, and has become the hot spots of current research and application.From the query point of view, wireless sensor networks could be regarded as a distributed database system, in which the sensor nodes sense and store data. Users propose the query requests, and then the interested data is send to the end user by the corresponding query processing, routing and data aggregation techniques via network nodes. Because the sensor nodes have strict resource constraints on the energy and communication, the traditional distributed database query techniques can not be directly applied in sensor networks.After analyzing and studying on the existing query processing techniques, this thesis focuses on processing multi-queries problem which is important but without much attention paid to. So a new Multi-Queries Framework (MQF) is presented for query processing problems in this thesis with the primary purpose of energy-saving. The system is mainly composed of five function modules: Window, Query Server, History Database in User Terminals, Query Manager in base station, and Query Filters in sensors, and among the five modules, Query Manager is the core of the entire system. Under the proposed framework, the thesis discusses Multi-queries classification algorithm and Multi-queries aggregation algorithm and the simulation results show that our algorithms can effectively save the energy consumption and prolong the network lifetime on the same query conditions.