Abstract
It has been widely accepted that the physical stimulation, like illumination, music and environmental variables having a 1/f fluctuation power spectrum, relaxes a person. There should, however, exist a number of the stimulation waveforms that have 1/f power spectral characteristics, and thus the parameters of the waveform in the time domain causing comfortable biostimulation remain unknown. As a first step in elucidating what kinds of biostimulation waveforms relax a person, this paper theoretically derives CRD (Crossing Rate Distribution: the number of times per one second where the amplitude crosses various levels in the positive direction) and APD (Amplitude Probability Distribution) for a Gaussian fluctuation waveform with a 1/f-like power spectrum. Flame fluctuation of candles which is said to cause a sedative effect to a person is statistically measured. The findings obtained here show that the flame has the peak crossing rate of 0.08 to 0.4Hz, fluctuating with the rhythm close to person's blood pressure (0.1Hz) or breathing (0.25-0.33Hz).
