an anticipated sensor application is to query a field of sensors and then take some action when one or more of the sensors is activated. for example,a surveillance system could notify a biologist if an animal enters a region. Coverage of deployed sensors will overlap to ensure robust coverage,so one event will likely trigger multiple sensors. All sensors will report detection to the user,but communication energy costs can be reduced if this data is aggregated as it returns to the user.Data can be aggregated to a binary value (there was a detection),an area (there was a detection in quadrant 2),or with some application-specific aggregation(seismic and infrared sensors indicate 80% chance of detection).