Abstract: A method and system are provided for constructing a discrete model using a multinomial tree structure with which a required memory capacity can be reduced and a realistic calculation time can be achieved, while ensuring a required calculation accuracy.

Abstract: A method for hiding message information into media information in frequency space. The data hiding method has high resistance to removal or change of message information embedded into media information and effectively maintain hidden message information even when signal processing is performed by employing a frequency filter. More specifically, in order to hide message information (m) into media information (M), the frequency transform of the message information (m) and the media information (M) are performed, and frequency spectra f1 and f2 are obtained. Next, from the frequency spectrum f2 of the message information (m), a region containing feature frequency components representative of the features of the message information (m) in real space is extracted as the base region B. Then, n copies of the base region B are generated, and in frequency space, the n copies are dispersedly arranged.

Abstract: A method of generating a low-discrepancy sequence at high speed including the steps of: (a) expanding an i-th coordinate value u.sup.(1) (1.ltoreq.i.ltoreq.k) of an n-th element (U.sub.n (1), . . . , U.sub.n (k)) of the low-discrepancy sequence in radix b, and storing m components generated by the expansion of each said coordinate value in sequence into a first storage, wherein the n is an integer equal to or more than 1 and the b is a prime number equal to or more than k; (b) expanding the number n in radix b, and storing the generated expansion (n.sub.m,.sup.(1), n.sub.m-1, . . . , n.sub.1) in sequence into a second storage; (c) scanning the second storage in sequence, and detecting a minimum order j, wherein n is not equal to b-1; (d) in response to the step (c), reading out j-th row components of a generator matrix T.sup.(1) for the i-th coordinate (1.ltoreq.i.ltoreq.

Abstract: A method and system are provided for generating a low-discrepancy sequence at high speed, comprising means for expanding an i-th coordinate value u.sub.n.sup.(i) (1.ltoreq.i.ltoreq.k) of an n-th element of the low-discrepancy sequence (u.sub.n.sup.i, . . . , u.sub.n.sup.(k)) in b scale, and storing m components created by the expansion of each value in sequence into a first storage means, wherein the above n is an integer equal to or more than 1 and the above b is a prime number equal to or more than k; means for expanding the number n in b scale, and storing the created expansion (n.sub.m, n.sub.m-1, . . . , n.sub.1) in sequence into a second storage means; means for scanning the second storage means in sequence, and detecting a minimum order j wherein nj is not equal to b-1; and means, respondent to the means for scanning, for reading out j-th row components of a low-discrepancy generator matrix T.sup.(i) stored in advance for an i-th coordinate value (1.ltoreq.i.ltoreq.