Abstract
The purpose of this study is to examine the condition of "comfortable swing." The familiar swings in which the period of the fundamental waveform is almost fixed are selected. Especially, the swings produced by a human are focused. And, the three-axial acceleration waveforms are measured on the ear near the semicircular canals of examinee, because a swing of the low frequency seems to be sensed in the semicircular canals which sense the posture. Then, the envelopes of the waveforms are examined by the frequency analysis. In addition, the acceleration waveforms on the body in lying on the floating air mat in the calm sea are measured, because the popular answer for the question with "what is the most pleasant swing for you?" is "floating on the water." As the result, it is shown that the swings produced by a human for own pleasant have the relationship of 1/f in the range from 0.005 to 0.1Hz.
