Date Added: Aug 2012
A Wireless Sensor Network (WSN) is a wireless network consisting of distributed autonomous devices using sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants, at different locations. A WSN Consists of ten to thousand of sensor nodes that communicate through wireless channels for information sharing and cooperative processing. In this paper, the authors' main focus is on base station energy-efficient queries optimization. Different from existing query optimization techniques that consider only query plans for extracting data from sensors at individual nodes, their approach takes into account both of the sensing and communication cost in query plans.