Hirosuke Yamamoto / Professor / Division of Transdisciplinary Sciences
Department of Complexity Science and Engineering / / Information Theory and Cryptology

Career Summary
1975: Graduated, Faculty of Engineering, Shizuoka University
1977: Master of Engineering from The University of Tokyo
1980: Doctor of Engineering from The University of Tokyo
1980: Research Associate, Tokushima University
1981: Lecturer, Tokushima University
1983: Associate Professor, Tokushima University
1987: Associate Professor, University of Electro-Communications
1993: Associate Professor, The University of Tokyo
1999: Professor, Graduate School of Engineering, The University of Tokyo
2001: Professor, Graduate School of Information Science and Technology, The University of Tokyo
2004: Professor, Graduate School of Frontier Sciences, The University of Tokyo

Educational Activities
Graduate school:Theory of Information and Coding I, Theory of Information and Coding II
Research Activities
Information Theory (Shannon Theory, Multiterminal Information Theory, Rate-Distortion Theory, Information Spectrum Theory, LDPC code, Network coding, etc.)
Cryptology (Information-theoretic Cryptology, Secret Sharing Schemes, Visual Cryptography, Broadcast encryption, etc.)
Data Compression Algorithms

1)T.Okamoto and H.Yamamot, "Modern Cryptography" Sangyotosho Inc., 1997 (in Japanese)
2) M.Iwamoto, H.Yamamoto, and H. Ogawa, "Optimal multiple assignments based on integer programming in secret sharing with general access structures", IEICE Trans. on Fundamentals, vol.E90-A, no.1, pp.101-112, Jan. 2007
3) M.Iwamoto and H.Yamamoto, "Strongly Secure Ramp Secret Sharing Schemes for General Access Structures", Information Processing Letters, vol.97, issue 2, pp.52-57, Jan. 2006
4)T.Ogawa, A.Sasaki, M.Iwamoto, H.Yamamoto, "Quantum Secret Sharing Schemes and Reversibility of Quantum Operations", Physical Review A, vol.72, no.3, pp.032318-1-7, Sept. 2005
5) M. Arimura and H.Yamamoto, "Asymptotic redundancy of the MTF scheme for stationary ergodic sources", IEEE Trans. on Inform. Theory, vol.51, no.11, pp.3742-3752, Nov. 2005.
6) H.Koga and H.Yamamoto, "Asymptotic properties on the codeword lengths of optimal FV codes for general sources", IEEE Trans. on Inform. Theory, vol.51, no.4, pp.1546-1555, April 2005.
7)Y.Matsunaga and H.Yamamoto, "A coding theorem for lossy data compression by LDPC codes", IEEE Trans. on Inform. Theory, vol.49, no.9, pp.2225-2229, Sep. 2003.
8) H.Yamamoto and H.Yokoo, "Average-sense optimality and competitive optimality for almost instantaneous VF codes", IEEE Trans. on Inform. Theory, vol.47, no.6, pp.2174-2184, Sep. 2001.
9)H.Yamamoto, "A new recursive universal code of the positive integers", IEEE Trans. on Inform. Theory, vol.46, no.2, pp.717-723, March 2000.
10)H.Yamamoto, "Rate-distortion theory for the Shannon cipher system", IEEE Trans. on Inform. Theory, vol.43, no.3, pp.827-835, May 1997.
11)H.Yamamoto, "Source coding theory for a triangular communication system", IEEE Trans. on Inform. Theory, vol.42, no.3. pp.848-853, May 1996.
12)H.Yamamoto and T.Itoh, "Competitive optimality of source codes", IEEE Trans. on Inform. Theory, vol.41, no.6, pp.2015-2019, Nov. 1995.
13) H.Yamamoto, "Coding theorems for Shannon's cipher system with correlated source outputs, and common information", IEEE Trans. on Inform. Theory, vol.40, no.1, pp.85-95, Jan. 1994.
14) H.Yamamoto, "Coding theorem for secret sharing communication systems with two noisy channels", IEEE Trans. on Inform. Theory, vol.35, no.3, pp.572-578, May 1989
15)H.Yamamoto, "Source coding theory for cascade and branching communication systems", IEEE Trans. on Inform. Theory, vol.IT-27, no.3, pp.299-308, May 1981
16)H.Yamamoto and K.Itoh, "Viterbi decoding algorithm for convolutional codes with repeat request", IEEE Trans. on Inform. Theory, vol.IT-26, no.5, pp.540-547, Sep. 1980.

Other Activities
IEEE (Institute of Electrical and Electronics Engineers)
IEICE (Institute of Electronics, Information and Communication Engineers of Japan) Fellow
SITA (Society of Information Theory and its Applications)

Chair of IEEE Information Theory Society Japan Chapter (2002-2003), Associate Editor of IEEE Transactions on Information Theory (2007-2010), Director of SITA (1994-1995 and 1998-2001), Vice President of SITA (2004-2005), Auditor of SITA (2006-2007), President of SITA (2007-2008), Vice President of ESS in IEICE, Editor of IEICE Transactions of Fundamentals (1997-2001), Editor of OUYOUSURI (1995-1998), TPC (Technical Program Committee) Co-chair ofd
ISITA (International Symposium on Information Theory and its Applications) 2004,
TPC Chair of ISITA2008
Future Plan
We are currently investigating new fields in the information theory, e.g. information spectrum theory, network coding, LPDC coding and quantum information theory, in addition to basic open problems in the traditional fields such as tree coding, universal data compression, Shannon theory, rate-distortion theory, multi-terminal information theory, information-theoretic cryptology, etc.
Messages to Students
In Shannon Theory, we are trying to prove coding theorems that clarify the theoretical bounds of coding rates for various communication systems. The coding theorems, if they are adequately validated, can become 'eternal truths' that will be cited many times in future researches. I hope that young researchers will strive to bring new fundamental, rather than "fashionable", innovations to their research fields.