Hiroshi Sekigawa

Senior Research Scientist
Computing Theory Research Group
Innovative Communication Laboratory
NTT Communication Science Laboratories
3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198 Japan
E-Mail: sekigawaXtheory.brl.ntt.co.jp (X = @)

Last modified: August 19, 2009

Research Interests

• Symbolic and Algebraic Computation
• Symbolic-Numeric Computation

Biography

1989.4: Joined Nippon Telegraph and Telephone Corporation (NTT)

1989.5 - 1994.6:

Research on computer-aided design for LSIs

1994.6 - 2000.3:

Research on symbolic and algebraic computation, symbolic-numeric computation

2000.4 - 2002.3: Business Communications Headquarters, Nippon Telegraph and Telephone West Corporation

2002.4 - : NTT

Research on symbolic and algebraic computation, symbolic-numeric computation

Society Membership

• Information Processing Society of Japan (IPSJ)
• Japan Society for Symbolic and Algebraic Computation (JSSAC)
  
• The Institute of Electronics, Information and Communication Engineers (IEICE)
• The Japan Society for Industrial and Applied Mathematics (JSIAM)

Selected Publications

• K. Shirayanagi and H. Sekigawa, Reducing Exact Computations to Obtain Exact Results Based on Stabilization Techniques, Proc. International Workshop on Symbolic-Numeric Computation 2009 (SNC2009), pp. 191-197, 2009.
• H. Sekigawa, On Real Factors of Real Interval Polynomials, Journal of Symbolic Computation, Vol. 44, No. 7, pp. 908-922, 2009.
• Y. Nakajima, Y. Kawano, H. Sekigawa, M. Nakanishi, S. Yamashita, and Y. Nakashima, Synthesis of Quantum Circuits for d-level Systems by using Cosine-Sine Decomposition, Quantum Information and Computation, Vol. 9, No. 5&6, pp. 423-443, 2009.
• H. Sekigawa, Combining Symbolic and Numeric Computation, (in Japanese), IPSJ Magazine, Vol. 50, No. 4, pp. 342-348, 2009.

• K. Shirayanagi and H. Sekigawa, A New Groebner Basis Conversion Method Based on the Stabilization Techniques, Theoretical Computer Science, Vol. 409, pp. 311-317, 2008.
• H. Sekigawa, The Nearest Polynomial with a Zero in a Given Domain, Theoretical Computer Science, Vol. 409, pp. 282-291, 2008.
• H. Sekigawa, The Nearest Real Polynomial with a Real Multiple Zero in a Given Real Interval, Proc. Asian Symposium on Computer Mathematics 2007 (ASCM2007), Lecture Notes in Computer Science 5081, pp. 32-41, 2008.
• H. Sekigawa, The Nearest Polynomial with a Zero in a Given Domain from a Geometrical Viewpoint, Proc. International Symposium on Symbolic and Algebraic Computation (ISSAC2008), pp. 287-294, 2008.
• Y. Nakajima, Y. Kawano, and H. Sekigawa, Efficient Quantum Circuits for Approximating the Jones Polynomial, Quantum Information and Computation, Vol. 8, No. 5, pp. 489-500, 2008.

• H. Sekigawa and K. Shirayanagi, On the Location of Pseudozeros of a Complex Interval Polynomial, Mathematics in Computer Science, Vol. 1, No. 2, pp. 321-335, 2007.
• Y. Nakajima, Y. Kawano, and H. Sekigawa, Synthesis of Quantum Circuits for d-level Systems, Proc. Asian Conference on Quantum Information Science (AQIS2007), pp. 135-136, 2007.
• H. Sekigawa, On Real Factors of Real Interval Polynomials, Proc. International Symposium on Symbolic and Algebraic Computation (ISSAC2007), pp. 331-338, 2007.
• P. Khungurn, H. Sekigawa, and K. Shirayanagi, Minimum Converging Precision of the QR-Factorization Algorithm for Real Polynomial GCD, Proc. International Symposium on Symbolic and Algebraic Computation (ISSAC2007), pp. 227-234, 2007.
• H. Sekigawa, The Nearest Polynomial with a Zero in a Given Domain, Proc. International Workshop on Symbolic-Numeric Computation 2007 (SNC2007), pp. 190-196, 2007.
• H. Sekigawa and K. Shirayanagi, On the Location of Zeros of an Interval Polynomial, Symbolic-Numeric Computation, D. Wang and L. Zhi (eds.), Birkhaeuser, pp. 167-184, 2007.

• H. Sekigawa and K. Shirayanagi, Locating Real Multiple Zeros of a Real Interval Polynomial (in Japanese), Journal of Japan Society for Symbolic and Algebraic Computation, Vol. 13, No. 1, pp. 68-71, 2006.
• Y. Nakajima, Y. Kawano, and H. Sekigawa, Quantum Circuit Design (in Japanese), IPSJ Magazine, Vol. 47, No. 12, pp. 1335-1340, 2006.
• T. Moriya, N. Harada, Y. Kamamoto, and H. Sekigawa, MPEG-4 ALS--International Standard for Lossless Audio Coding, NTT Technical Review, Vol. 4, No. 8, pp. 40-45, 2006.
• H. Sekigawa and K. Shirayanagi, Locating Real Multiple Zeros of a Real Interval Polynomial, Proc. International Symposium on Symbolic and Algebraic Computation (ISSAC2006), pp. 310-317, 2006.
• K. Miyamoto, W. Yamamoto, H. Sekigawa, and K. Shirayanagi, Deductive System for Human-like Proofs in Geometry, Proc. 13th Symposium on the Integration of Symbolic Computation and Mechanized Reasoning 2006 (Calculemus'06), pp. 5-20, 2006.
• H. Sekigawa and K. Shirayanagi, On the Location of Zeros of an Interval Polynomial (in Japanese), IEICE Trans. A, Vol. J89-A, No. 3, pp. 199-216, 2006.
• N. Harada, T. Moriya, H. Sekigawa, K. Shiaryanagi, and Y. Kamamoto, Lossless Compression of IEEE754 Floating-Point Signal in ISO/IEC MPEG-4 Audio Lossless Coding (ALS) (in Japanese), IEICE Trans. B, Vol. J89-B, No. 2, pp. 204-213, 2006.
• Y. Nakajima, Y. Kawano, and H. Sekigawa, A New Algorithm for Producing Quantum Circuits using KAK Decompositions, Quantum Information & Computation, Vol. 6, No. 1, pp. 67-80, 2006.

• H. Sekigawa and K. Shirayanagi, On the Location of Zeros of a Real Interval Polynomial (in Japanese), Journal of Japan Society for Symbolic and Algebraic Computation, Vol. 12. No. 2, pp. 35-38, 2005.
• H. Sekigawa and K. Shirayanagi, On the Location of Pseudozeros of a Complex Interval Polynomial, Proc. Asian Symposium on Computer Mathematics (ASCM2005), pp. 231-234, 2005.
• H. Nakajima, Y. Kawano, and H. Sekigawa, An Algorithm for Decomposing Unitary Matrices using Cartan Decomposition, Abstracts of 11th International Conference on Applications of Computer Algebra (ACA'2005), p. 24, 2005.
• H. Sekigawa and K. Shirayanagi, On the Location of Zeros of a Complex Interval Polynomial, Abstracts of 11th International Conference on Applications of Computer Algebra (ACA'2005), p. 15, 2005.
• H. Sekigawa and K. Shirayanagi, On the Location of Zeros of an Interval Polynomial, Proc. International Workshop on Symbolic-Numeric Computation 2005 (SNC2005), pp. 144-165, 2005.
• Y. Kawano, K. Kimura, H. Sekigawa, M. Noro, and K. Shirayanagi, Exact CNOT on an Exchange-Only Quantum Computer (in Japanese), Journal of Japan Society for Symbolic and Algebraic Computation, Vol. 11. No. 2, pp. 55-58, 2005.
• Y. Kawano, K. Kimura, H. Sekigawa, M. Noro, K. Shirayanagi, M. Kitagawa, and M. Ozawa, Existence of the Exact CNOT on a Quantum Computer with the Exchange Interaction, Quantum Information Processing, Vol. 4, No. 2, pp. 65-85, 2005.
• N. Harada, T. Moriya, H. Sekigawa, and K. Shiaryanagi, Lossless Compression of IEEE Floating-point Audio using Approximate Common Factor Coding and Masked-LZ Compression, Poster presentation at AES 118th Convention, 2005.

• H. Sekigawa, Zero Determination of Algebraic Numbers using Approximate Computation (in Japanese), Bulletin of the Japan Society for Industrial and Applied Mathematics, Vol. 14, No. 4, pp. 75-78, 2004.
• K. Miyamoto, K. Ohya, H. Sekigawa, and K. Shirayanagi, An Efficient Method of Finding Auxiliary Lines in Automated Geometry Theorem Proving (in Japanese), Proc. of the RIMS Workshop "Computer Algebra--Design of Algorithms, Implementations and Applications," Kokyuroku 1395, pp. 157-163, Research Institute for Mathematical Sciences, Kyoto Univ., 2004.
• Y. Kawano, K. Kimura, and H. Sekigawa, On Quantum Gates in Decoherence-Free Subspaces (in Japanese), Technical Report of IEICE, COMP2004-23, pp. 33-39, 2004.

• K. Miyamoto, H. Sekigawa, K. Shirayanagi, and F. Machida, On a Method for Automated Generation of Readable Proofs in Euclidean Geometry (in Japanese), Proc. of the RIMS Workshop "Computer Algebra--Algorithms, Implementations and Applications," Kokyuroku 1335, pp. 20-27, Research Institute for Mathematical Sciences, Kyoto Univ., 2003.

• K. Shirayanagi and H. Sekigawa, New Scientific Computing--Symbolic-Numeric Algebra (in Japanese), NTT R&D, Vol. 51, No. 10, pp. 778-783, 2002.

• H. Sekigawa, A Remark on the Polynomial Determining Superstable Points in the Mandelbrot Set, Josai Mathematical Monographs 2, NLA99 Computer Algebra, pp. 11-13, 2000.
• H. Sekigawa and K. Shirayanagi, Automatic Algorithm Stabilization System, Josai Mathematical Monographs 2, NLA99 Computer Algebra, pp. 159-168, 2000.

• H. Sekigawa and K. Koyama, Nonexistence Conditions of a Solution for the Congruence x₁^k+...+x_s^k=N (mod pⁿ), Mathematics of Computation, Vol. 68, No. 227, pp. 1283-1297, 1999.

• H. Sekigawa, Using Interval Computation with the Mahler Measure for Zero Determination of Algebraic Numbers, Josai Information Sciences Researches, Vol. 9, No. 1, pp. 83-99, 1998.

• K. Shirayanagi and H. Sekigawa, An Interval Method Based on Zero Rewriting and its Application to Sturm's Algorithm (in Japanese), IEICE Trans. A, Vol. J80-A, No. 5, pp. 791-802, 1997.
• K. Koyama, Y. Tsuruoka, and H. Sekigawa, On Searching for Solutions of the Diophantine Equation x³+y³+z³=n, Mathematics of Computation, Vol. 66, No. 218, pp. 841-851, 1997.

• H. Sekigawa, Using Interval Arithmetic and Polynomial Norms to Determine Signs of Algebraic Numbers, Proc. 2nd Asian Symposium on Computer Mathematics (ASCM'96), pp. 43-53, 1996.
• H. Sekigawa, An Interval Arithmetic with Algebraic Complexity to Determine the Signs of Algebraic Expressions, Abstracts of 4th International Symposium on Effective Methods in Algebraic Geometry (MEGA'96), p. 43, 1996.

• H. Sekigawa and K. Shirayanagi, Computing Diophantine Approximate Groebner Bases, Proc. 1st Asian Technology Conference in Mathematics (ATCM'95), pp. 717-726, 1995.
• H. Sekigawa and K. Shirayanagi, Zero Rewriting in Interval Computation and Its Application to Sturm's Algorithm, Poster presentation at International Symposium on Symbolic and Algebraic Computation (ISSAC'95).