Advances in the miniaturization of microelectromechanical systems have led to battery-powered sensor nodes that have sensing, communication and p- cessingcapabilities. Thesesensornodescanbenetworkedinanadhocmanner to perform distributed sensing and information processing. Such ad hoc s- sor networks provide greater fault tolerance and sensing accuracy and are typically less expensive compared to the alternative of using only a few large isolated sensors. These networks can also be deployed in inhospitable terrains or in hostile environments to provide continuous monitoring and processing...