Abstract: A method of judging a biological state comprising using: (1) correlation and/or symmetry between Lyapunov exponent and entropy; and/or (2) Higuchi fractal dimension, wherein the Lyapunov exponent, entropy and Higuchi fractal dimension are indices that can express chaotic nature and derived from time series data of biological signals from a subject.

Abstract: A human condition evaluation system, of which bio-signal analysis means includes a bio-signal peak value detection means for detecting a peak value for each cycle of an original waveform of a bio-signal data, and a power value calculation means for calculating a difference between the peak value at an upper limit side and the peak value at a lower limit side for every prescribed time range using respective peak values obtained by the bio-signal peak value detection means to thereby set the difference as a power value, is structured to determine a predictive signal for falling asleep from an active state into a sleep state. Different from conventional human condition evalution based simply on a Lyapunov exponent as an indicator, a new human condition evaluation system based on a functional status of an energy generation system of the living body is provided.

Abstract: A toy for pets, which is designed to encourage sedentary pets to exercise by attracting them to the chaotic movement of a movable object, is provided. The toy for animals includes a rotating unit, which is provided so as to allow the axis of rotation to be angled with respect to the vertical direction; a first rod having a base portion connected coaxially with the axis of rotation and a tip portion bent with respect to the base portion; a second rod, which is connected to the tip portion of the first rod and has enough flexibility to be deflected from the longitudinal direction; and a movable object mounted to the tip of the second rod with a string material. The movable object is moved chaotically in the vertical and horizontal directions within a three-dimensional space around the rotating unit by chaotically rotating the axis of rotation of the rotating unit in an arbitrary rotating direction.