A widely cited application of sensor networks is event- detection, where a large network of nodes is used to iden- tify regions or resources that are experiencing some phe- nomenon of particular concern to the user. Examples in- clude condition-based maintenance in industrial plants [14], where engineers are concerned with identifying ma- chines or processes that are in need of repair or adjustment, process compliance in food and drug manufacturing [25], where strict regulatory requirements require companies to certify that their products did not exceed certain environ- mental parameters during processing, and applications centered around homeland security, where shippers.
