A curved surface area calculation device and method generates a contour curve consisting of border points of a curved surface, and determines an approximate poly-line of the contour curve in a parametric plane. The output register may be configured to output data based on a delayed clock signal. In a further embodiment, the inability or difficulty of a patient to voluntarily expel potentially threatening fluid and matter from the patient’s airway can be remedied by repeated applications of the aerosol chemostimulant spray. The transaxle and the battery are disposed below the load carrying bed so as to overlap the load carrying bed when viewed in plan. The rise time may be estimated in response to applying a common-mode voltage step at the transmitter output, for example. Results of the inquiry are also stored in the in-use-address DB.