1. Mobile middleware, comprising: a Context Monitoring Query (CMQ) processor configured to store requested CMQs received from context-aware application programs, and configured to receive sensor data from at least one sensor, and configured to monitor whether the stored CMQs are satisfied with reference to the received sensor data, and configured to transmit an event to the context-aware application programs according to results of the monitoring; a Reduced Source Cover (RSC) manager configured to control activation of the at least one sensor so that only sensor data required to be used to determine whether the requested CMQ is satisfied is generated and transmitted to the Context Monitoring Query (CMQ) processor so as to reduce energy consumption during the performance of the monitoring a data processor configured to receive the sensor data from the sensors and to transmit the sensor data to the CMQ processor.