Analysis And Improvement Of Wireless Sensor Network Database Tinydb

Large-scale network of wireless sensors, which is the integration of sensor techniques, embedded computation techniques, distributed computation techniques and wireless communication techniques, has a prospective future of application. It is a brand-new area to make sensor networks virtual databases with effective data management and data acquisition.This thesis firstly analyzes the full source codes of TinyDB, the most famous wireless sensor network database prototype, by which it lays solid foundation for the future system migration and improvement. TinyDB system consists of two parts: the front-end and the embedded database engines. The front-end of this kind database is an interface between applications and sensor networks, which regards the wireless sensor networks as the unique relation databases. Applications retrieve data from the only table named sensors that map each kind of sensor networks data to one field. The front-end builds messages to load context of many kinds of queries, e.g. event-based queries, and then disseminates them sequentially into the sensor networks. The front-end is also responsible for handling all coming query results and dispatches them. The other part of this database needs an embedded database engine running inside every sensor network node. This thesis studies issues on design and implementation of the engine, including data schema, distributive execution of queries, in-networking aggregation and grouping, nodes collaboration and so on.In the third part of the thesis, a distributive join algorithm is described, which can support complex data filtering and event-detection in many surveillance applications. It assembles complex predicates into one static table that is pushed into and stored inside nodes. This algorithm performs join queries over sensors table and static tables in-networking. Both algorithm analysis and experiments show data traffic reduce obviously if the selectivity of static table is low.At last, the primary work is summarized, and some future works are stated.