A battery pack is communicated with a luggage compartment via an outlet such that cooling air that has been heat transferred with a battery is released into the luggage compartment. The device further includes a source region of a first conductivity type and a drain region of a second conductivity type provided in the substrate to sandwich the gate electrode, and a channel region provided between the source and drain regions in the substrate. Accordingly, the number of times of broadcasting may be controlled according to the average of received time offsets in the wireless sensor network.