Information Security

• Kunihiro, N. and Yamamoto, H. (Univ. of Tokyo): Extended Window Method for Addition-Subtraction Chain, Proc. of the 7th Japan-Benelux Workshop on Information Theory (1997).
• Kunihiro, N. and Yamamoto, H. (Univ. of Tokyo): Window and Extended Window Methods for Addition Chain and Addition-Subtraction Chain, IEICE Trans. Fundamentals, Vol.E81-A, No.1, pp. 72-81 (1998).
• Kunihiro, N. and Koyama, K.: Reducing Integer Factoring to Computing the order of Elliptic Curve over Z_n for Composite n (in Japanese), Proc. of the 1998 Symposium on Cryptography and Information Security, SCIS98-7.1.C, (1998).
• Koyama, K., Tsuruoka, Y. and Sekigawa, H.: On Searching for Solutions of the Diophantine Equation x^3+y^3+z^3=n, Mathematics of Computation, Vol.66, No.218, pp. 841-851 (1997).
• Koyama, K. and Okamoto,T.: NTT's Research and Development of Public-key Cryptosystems, Proc. of PKS'97 Conference, April, (1997).
• Koyama, K.: Challenge for Elegant Solution [Problem: Obtain integer solutions of y^2=x^3+9] (in Japanese), Sugaku Seminar, Aug., p. 97, Nihonhyoronsha (1997).
• Koyama, K.: Challenge for Elegant Solution [Solution and Comment] (in Japanese), Sugaku Seminar, Nov., pp. 105-107, Nihonhyoronsha (1997).
• Koyama, K.: Elliptic Curve Cryptosystems I (in Japanese), Nikkei Digital Money Sysstems, July, Nikkei-BP Co. (1997).
• Koyama, K.: Elliptic Curve Cryptosystems II (in Japanese), Nikkei Digital Money Sysstems, August, Nikkei-BP Co. (1997).
• Koyama, K.: Number Theory and Modern Cryptosystems (in Japanese), Sugaku Seminar, March, pp. 22-26, Nihonhyoronsha (1998).
• Koyama, K.: Cryptology (in Japanese), Digital Daijiten (Encyclopedia), Nikkei-BP Co. (1998).
• Tsuruoka, Y. and Koyama, K.: Fast modular multiplications based on precomputations with less memory, Electronics Letters, Vol.33, No.16, pp. 1370-1371 (1997).
• Tsuruoka, Y. and Koyama, K.: Security analysis based on diophantine equation for RSA-type elliptic curve cryptosystems (in Japanese), Proc. of SCIS98, SCIS98-4.1.E (1998).

Emotion Transmission Theory

• Koyama, K.: Why are we conducting research on emotional psycology? (in Japanese), Japan Emotion psycology Society News Letters, Vol.5, No.1, p. 5, Sept., (1997).
• Nakamura, T., Koyama, K. and Nishio, S.: Analysis of ``Laughter of Claque'' in time differences of facial and abdominal movements (in Japanese), Proc. 5th Annual Convention of Japan Society for Research on Emotions, p. 17 (1997).
• Nishio, S., Koyama, K. and Nakamura, T.: Effect of observer's viewpoint on classification of smiles (in Japanese), Proc. 5th Annual Convention of Japan Society for Research on Emotions, p. 16 (1997).
• Nishio, S. and Koyama, K.: A Criterion for Facial Expression of Laugh Based on Temporal Difference of Eye and Mouth Movement (in Japanese), Trans. IEICE, Vol.J80-A, No.8, pp. 1316-1318 (1997).
• Nishio, S., Koyama, K., and Nakamura, T.: Effect viewpoint angle on classification of smiles (in Japanese), Proc. 2nd Annual Convention Japan Academy of Facial Studies, p. 13 (1997).
• Nishio, S., Koyama, K. and Nakamura, T.: The Effect of Attention on Classifying Facial Expressions of Smile, Technical report of IEICE, Vol.PRMU97, No.386, pp. 61-68 (1997).
• Koyama, K.: Systematic Evaluation of Naked King Mating Problem (in Japanese), Proc. of Game Programing Workshop, Computer Shogi Association, October (1997).

Data Compression Theory

• Muramatsu, J. and Iwata, K. (Matsuyama Shinonome Collage): Lossless Universal Data Compression Algorithms with Common Side Information Based on Reccurence Time (in Japanese), Proc. of the 20th Symposium on Information Theory and Its Applications, pp. 809-812 (1997).
• Muramatsu, J. and Kanaya, F. (Shonan Institute of Technology): A Universal Data Compression with Common Side Information, Proc. of the 1997 IEEE International Symposium on Information Theory, p. 183 (1997).
• Kanaya, F. (Shonan Institute of Technology) and Muramatsu, J.: An Almost Sure Recurrence Theorem with Distortion for Stationary Ergodic Sources, IEICE Trans. Fundamentals, Vol.E80-A, No.11, pp.2264-2267 (1997).