In an emulation system, a method is provided to schedule evaluations of state elements and memory elements receiving signals from multiple asynchronous clock domains, such that causality and hold time requirements are satisfied. If both blood pressure estimated from the pulse wave propagation time and a waveform parameter obtained from the accelerated pulse wave have abnormal values, it is determined that the blood pressure is truly fluctuating, and blood pressure measurement by another method, e. The digital audio data outputted from the error detecting and correcting device is inputted to an impulse noise suppressing circuit. A passenger may make a reservation for transportation service at a kiosk and receive a voucher that may be collected or validated by the service provider at the time of transport.