The present disclosure provides a mobile terminal. Therefore, travel wind is passed on outer surfaces of the bulges to traverse the lower end edge, thereby generating a negative pressure or vacuum at a lower portion of the chin-covering portion to draw out the user’s breath in the breathing space to below the chin-covering portion. The housing assembly can have a wireless transceiver that exchanges messages with at least one among a plurality of cellular base stations, and a controller that manages operations of the wireless transceiver and the MHDD storage medium. A sound velocity V in the material is estimated from the frequency f and the interference signals Ri. Whenever a computation has been finished, a pulse is supplied at the validity output whose frequency may be maximally equal to the system clock frequency.