PURPOSE: To preserve the inclination of learning and to prevent improper correction of the input/output characteristic at the time of update learning of neural network (NN).
CONSTITUTION: Heterogeneity degree calculating means 300 and 302 and data update means (304 and 306) are provided, and former means calculate the degree of heterogeneity of new teacher data based on the difference between output data of the NN corresponding to new input data and new teacher data when new input data and new teacher data are added to perform update learning for the purpose of changing the input/output characteristic of the NN, and latter means adds new input and teacher data to data for learning in the case of the degree of heterogeneity smaller than a threshold changed in accordance with the frequency in update learning but do not add them in the case of the degree of heterogeneity larger than the threshold, and update learning of the NN is performed based on updated data. The input/output characteristic is not largely corrected in the case of the convergent state.
KATO TOMOYA
HATTORI KAZUYA
