Energy-Efficient Monitoring of Spatial Predicates over Moving Objects Haibo Hu and Dik Lun Lee   View Paper (PDF)   Return to September 2005, Database Issues for Location Data Management, Volume 28, Number 3 Abstract We study the problem of monitoring the changes of predicates on the spatial relations between objects, which is fundamental for many monitoring and tracking applications. As the location update problem is the core of object monitoring, we develop a cost model on the power consumption and propose a family of energy-efficient location update schemes. In these schemes, upon each location update the server sends back additional information about the predicates so that the client can defer the next update until it is about to change the predicate value. As a result, the updates are less frequent than the traditional periodic or dead-reckoning schemes without undermining the monitoring accuracy. ©2006 Association for Computing Machinery