The correlation between a coded block on the screen of the current image and a plurality of candidate blocks which exist in a search area on a reference screen temporally different from the current image and which has the same area as that of the coded block is obtained to select a candidate block having the highest correlation to obtain its displacement as a primary motion vector. In response to discovering the group of resources, the agent associates member resources of the group of resources to a corresponding group identifier to which the member resources belong. Likewise, inbound content indicators at different layers are compared to detect potential inbound data modifications. In some implementations, a compression ratio may be customized for determining the sizing of the common component and individual component. The load short-circuit detection circuit detects an abnormal oscillation waveform signal caused by a short-circuit state between the both ends of the motor.