Abstract: The present invention applies a particle filter method to the PUCK model for calculating a true market price. First, a probability density function of a parameter is obtained by generating a group of particles having parameters representing the state of the PUCK model each having different values. Then, the degree of conformity of each of the particles is evaluated and the particles are resampled as follows in accordance with the degree of conformity. A random number is compared with a predetermined value, where particles are regenerated in accordance with probability density function such as a normal distribution for making a parameter value of the model at time (t) into a mean value when the random number is greater than the predetermined value, and where the particles are regenerated taking a uniform distribution as the probability density function when the random number is less than the predetermined value.

Abstract: An open market is made up of numerous dealers, and each dealer is allowed to freely set selling and buying prices. Dealers tend to predict prices while being affected by recent price changes, and to determine trading prices such as selling prices and buying prices accordingly. Also, in the overall trading market, there is a price at which the selling prices and buying prices decided by each dealer are balanced, i.e., a virtual equilibrium price. While trading prices can be observed in a real trading market, the virtual equilibrium price cannot be observed. The present Inventors have transcendentally reached the two following properties in the open market; that trading prices change in the direction of narrowing the gap with the virtual equilibrium price, and that the virtual equilibrium price fluctuates according to the nature of dealers which is that dealers are affected by recent price changes.

Abstract: Two photodetectors output electric signals based on the detection of light at light receiving sections mutually spaced apart. The output signal of one of the photodetectors is delayed and a first pulse signal is generated, and second pulse signal having no delay is generated according to based on the detection signal of the other of the two photodetectors. A detection signal is output when the pulse signals overlap. According to whether the detection signal is output, a movement direction and speed of a moving body that moves between the light receiving sections are detected.

Abstract: Two photodetectors are formed which output electric signals based on the detection of light at light receiving sections disposed apart in space. The output signal of one of the photodetectors is delayed and a first pulse signal is generated. A second pulse signal having no delay is generated according to the detection signal of the other of the photodetectors. A signal is output when the pulse signals are input overlappingly. According to whether the signal is output, the movement direction and speed of a moving body which moves between the light receiving sections are detected.