Masato OKADA
Professor of Department of Complexity Science and Engineering,
Graduate School of Frontier Sciences, the University of Tokyo

Last updated: July 2, 2004

[English Papers] [International Conference Papers] [Curriculum Vitae] [Awards] [Academic Activities] [Research Grants] [Contact]


[English Papers]

  1. Narihisa Matsumoto and Masato Okada:
    Impact of deviation from precise balance of spike-timing-dependent plasticity.
    to be published in Neural Networks.
    http://arXiv.org/abs/cond-mat/0211503
  1. Masato Inoue, Hyeyoung Park and Masato Okada:
    Evaluation of the adaptive natural gradient descent method for soft committee machines.
    to be published in Physical Review d, 2004.
  1. Tatsuya Uezu, Aya Hirano and Masato Okada:
    Retrieval properties of Hopfield and correlated attractors in an associative memory model.
    to be published in Journal of Physical Society of Japan.
    http://arxiv.org/abs/cond-mat/0403361
  1. Seiji Miyoshi and Masato Okada:
    Storage capacity diverges with synapse efficiency in associative memory model with synaptic delay and pruning.
    to be published in IEEE Transactions on Neural Networks.
    http://arxiv.org/abs/cond-mat/0305517
  1. Tomoyuki Kimoto and Masato Okada:
    Coexistence of memory patterns and mixed states in a sparsely encoded associative memory model storing ultrametric patterns.
    to be published in Biological Cybernetics.
    http://arXiv.org/abs/cond-mat/0211428
  1. Invited paper
    Koji Wada, Koji Kurata, Masato Okada;
    Self-organization of globally continuous and locally distributed information representation.
    to be published in Neural Networks.
  1. Narihisa Matsumoto and Masato Okada:
    Neuronal Mechanisms for hierarchical encoding in inferior-temporal cortex.
    to be published in Neurocomputing.
  1. Narihisa Matsumoto and Masato Okada:
    Robustness of retrieval properties against imbalance between LTP and LTD of Spike-time-dependent plasticity.
    to be published in Physical Review E.
    http://arXiv.org/abs/cond-mat/0208079
  1. Masami Tatsuno and Masato Okada:
    Investigation on possible neural mechanisms underlying information geometric measures.
    to be published in Neural Computation.
  1. Kazuyuki Hara and Masato Okada:
    On-line learning through simple perceptron learning with a margin.
    Neural Networks, 17(2), 215-223, 2004.
  1. Yoichi Miyawaki and Masato Okada:
    A network model of perceptual suppression induced by transcranial magnetic stimulation.
    Neural Computation, 16, 309-331, 2004.
  1. Tomoyuki Kimoto and Masato Okada:
    Mixed states on neural network with structural learning.
    Neural Networks, 17, 103-112, 2004.
    http://arxiv.org/abs/cond-mat/0206559
  1. Seiji Miyoshi, Hiro-Fumi Yanai and Masato Okada:
    Associative memory by recurrent neural networks with delay elements.
    Neural Networks, 17, 55-63, 2004.
  1. Hyeyoung Park, Masato Inoue and Masato Okada:
    On-line learning dynamics of multilayer perceptrons with unidentifiable parameters.
    Journal of Physics A: Mathematical and General, 36, 11753-11764, 2003.
  1. Tomoko Ozeki and Masato Okada:
    Dynamical properties of Markov Chain Monte Carlo method for image restoration.
    Journal of Physics A: Mathematical and General, 36, 11011-11021, 2003.
  1. Tatsuto Murayama and Masato Okada:
    One-step RSB scheme for the rate distortion functions.
    Journal of Physics A: Mathematical and General, 36, 11123-11130, 2003.
    http://arXiv.org/abs/cond-mat/0207637
  1. Shigeaki Nishina, Masato Okada and Mitsuo Kawato:
    Spatio-temporal dynamics of depth propagation on uniform region.
    Vision Research, 43(24), 2493-2503, 2003.
  1. Masato Okada, Shigeaki Nishina and Mitsuo Kawato:
    The neural computation of the aperture problem: an iterative process.
    NeuroReport, 14(14), 1767-1771, 2003.
  1. Kazushi Mimura, Tomoyuki Kimoto and Masato Okada:
    Synapse efficiency diverges due to synaptic pruning following@over-growth.
    Physical Review E, 68, 031910, 2003.
    http://arXiv.org/abs/cond-mat/0207545
  1. Toru Aonishi and MasatoOkada:
    Dynamically-coupled oscillators - cooperative behavior via dynamical interaction -.
    Journal of Physical Society of Japan, 72(6), 1334-1337, 2003.
    http://arXiv.org/abs/cond-mat/0207506
  1. Masami Tatsuno and Masato Okada:
    How does information-geometric measure depend on underlying neural mechanism?
    Neurocomputing, 52-54, 649-654, 2003.
  1. Yoichi Miyawaki and Masato Okada:
    A network model of inhibitory effects induced by transcranial magnetic stimulation.
    Neurocomputing, 52-54, 837-842, 2003.
  1. Masaki Nomura, Toshio Aoyagi and Masato Okada:
    Two-level hierarchy with sparsely and temporally coded patterns.
    Neural Networks, 16, 947-954, 2003.
  1. Masaki Kawamura, Ryuji Tokunaga and Masato Okada:
    Low-dimensional chaos induced by frustration in a non-monotonic system.
    Europhysics Letters, 62(5), 657-663, 2003.
    http://arXiv.org/abs/cond-mat/0205471
  1. Masato Inoue, Hyeyoung Park and Masato Okada:
    On-line learning theory of soft committee machines with correlated hidden units.-- Steepest gradient descent and natural gradient descent --.
    Journal of Physical Society of Japan, 72(4), 805-810, 2003.
  1. Seiji Miyoshi and Masato Okada:
    Associative memory by neural networks with delays and pruning.
    Electronics and Communication in Japan Part 3, Fundamental Electronic Science, John Wiley & Sons, 86(6), 48-58, 2003.
  1. Tomoyuki Kimoto and Masato Okada:
    Sparsely encoded associative memory model with forgetting process.
    IEICE Transaction on Information and systems, E85-D(12), 1938-1945, 2002.
  1. Jun Tsuzurugi and Masato Okada:
    Statistical mechanics of the Bayesian image restoration under spatially correlated noise.
    Physical Review E, 66, 066704, 2002.
    http://arXiv.org/abs/cond-mat/0206286
  1. Hayaru Shouno, Koji Wada and Masato Okada:
    Naive mean field approximation for image restoration.
    Journal of Physical Society of Japan, 71(10), 2406-2413, 2002.
    http://arXiv.org/abs/cond-mat/0204624
  1. Narihisa Matsumoto and Masato Okada:
    Self-regulation mechanism of temporally asymmetric Hebbian plasticity.
    Neural Computation, 14, 2883-2902, 2002.
  1. Toru Aonishi, Koji Kurata and Masato Okada:
    Acceleration effect of coupled oscillator systems.
    Physical Review E, 65, 046223, 2002.
  1. Toru Aonishi and Masato Okada:
    Multibranch entrainment and slow evolution among branches in coupled oscillators.
    Physical Review Letters, 88(2), 024102, 2002.
    http://prl.aps.org/
    http://arXiv.org/abs/cond-mat/0104526
  1. Masaki Kawamura and Masato Okada:
    Transient dynamics for sequence processing neural network.
    Journal of Physics A: Mathematical and General, 35(2), 253-266, 2002.
    http://arXiv.org/abs/cond-mat/0202431
  1. Tomoyuki Kimoto and Masato Okada:
    Mixed state on a sparsely encoded associative memory model.
    Biological Cybernetics, 85(4), 319-325, 2001.
    http://arXiv.org/abs/cond-mat/9911187
  1. Toshiyuki Tanaka, Shinsuke Kakiya and Masato Okada:
    Application of two-parameter dynamical replica theory to retrieval dynamics of associative memory with non-monotonic neurons.
    Journal of Physics A: Mathematical and General, 34(13), 2695-2712, 2001.
    http://arXiv.org/abs/cond-mat/0010055
  1. Kaname Toya, Kunihiko Fukushima, Yoshiyuki Kabashima and Masato Okada:
    Bistability of mixed states in neural network storing hierarchical patterns.
    Journal of Physics A: Mathematical and General, 33(14), 2725-2738, 2000.
    http://arXiv.org/abs/cond-mat/9909276
  1. Tomoki Fukai, Tomoyuki Kimoto, Makoto Doi and Masato Okada:
    Coexistence of uncorrelated and correlated attractors in a nonmonotonic neural network.
    Journal of Physics A: Mathematical and General, 32(30), 5551-5562, 1999.
  1. Masaki Kawamura, Masato Okada and Yuzo Hirai:
    Dynamics of selective recall in an associative memory model with one-to-many associations.
    IEEE Transactions on Neural Networks, 10(3), 704-713, 1999.
  1. Toru Aonishi, Koji Kurata and Masato Okada:
    A statistical mechanics of an oscillator associative memory with scattered natural frequencies.
    Physical Review Letters, 82, 2800-2803, 1999.
    http://prl.aps.org/
    http://arXiv.org/abs/cond-mat/9808090
  1. Yoshio Yamaguchi, Kunihiko Fukushima and Masato Okada:
    A neural network model for associative recall of maps.
    Systems & Computers in Japan, 29, 386-394, 1998.
  1. Kazushi Mimura, Masato Okada and Koji Kurata:
    Associative memory model with forgetting process using nonmonotonic neurons.
    IEICE Transaction on Information and systems, E81-D, 1298-1304, 1998.
  1. Kazushi Mimura, Masato Okada and Koji Kurata:
    Robustness to noise of associative memory using nonmonotonic analogue neurons.
    IEICE Transaction on Information and systems, E81-D, 928-932, 1998.
  1. Masato Okada, Tomoki Fukai and Masatoshi Shiino:
    Random and systematic dilutions of synaptic connections in a neural network with a nonmonotonic response function.
    Physical Review E, 57, 2095-2103, 1998.
  1. Kunihiko Fukushima, Yoshio Yamaguchi and Masato Okada:
    Neural network model of the spatial memory: associative recall maps.
    Neural Networks, 10, 971-979, 1997.
  1. Invited paper
    Masato Okada:
    Notions of associative memory and sparse coding.
    Neural Networks, 9, 1429-1458, 1996.
  1. Kazushi Mimura, Masato Okada and Koji Kurata:
    Capacity of autocorrelation associative memory with quantized synaptic weight.
    Systems & Computers in Japan, 27, 55-63, 1996.
  1. Masato Okada:
    A hierarchy of macrodynamical equations for associative memory.
    Neural Networks, 8, 833-838, 1995.
  1. Michihiro Ohno, Masato Okada, Kunihiko Fukushima:
    Neocognitron learned by backpropagation.
    Systems & Computers in Japan, 26(5), 19-28, 1995.
  1. Kunihiko Fukushima, Masato Okada, Kazuhito Hiroshige:
    Neocognitron with dual C-cell layers.
    Neural Networks, 7, 41-47, 1994.
  1. Akio Kotani, Kozo Okada and Masato Okada:
    Theory of 3d-XPS and L3-XAS in CeF4.
    Solid State Communications, 64, 1479-1482, 1987.
  1. Akio Kotani, Takeo. Jo, Kozo Okada, Takashi Nakano, Masato Okada,
    A. Bianconi, A. Marcelli and J. C. Parlebas:
    High energy spectroscopy in Ce and La compounds.
    Journal of Magnetism and Magnetic Materials, 70, 28-32, 1987.
  1. Akio Kotani, Masato Okada, Takeo Jo, A. Bianconi, A. Marcelli and J. C. Parlebas:
    Many body effect in inner shell photoemission and photabsorption spectra of La compounds.
    Journal of the Physical Society of Japan, 56, 798-809, 1987.
  1. Akio Kotani, Masato Okada and Takeo Jo:
    Many body effects in core level spectra of Lanthanum compounds.
    Physics Scripta, 35, 566-569, 1987.
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[International Conference Papers]

  1. Yoichi Miyawaki and Masato Okada:
    Mechanism of neural interference by transcranial magnetic stimulation: network or single neuron?
    Neural Information Processing Systems (NIPS*2003)
    Vancouver, British Columbia, Canada, Dec.2003.
  1. Toru Aonishi, Hiroyoshi Miyawaki, Masashi Inoue and Masato Okada:
    Boosting of signal transmission speed and bistability structure by A-type potassium channels.
    Society for Neuroscience 33rd Annual Meeting, 2003.
  1. Narihisa Matsumoto, Daisuke Ide, Masataka Watanabe and Masato Okada:
    Retrieval property of an attractor network with depressing synapses.
    Society for Neuroscience 33rd Annual Meeting, 2003.
  1. Koji Wada, Koji Kurata and Masato Okada:
    Self-organization of globally continuous and locally distributed information representation.
    Workshop on Self-Organizing Maps (WSOM'03), --Intelligent systems and innovational computing--.
    Hibikino, Kitakyushu, Japan, 2003.
  1. Narihisa Matsumoto and Masato Okada:
    Neuronal Mechanisms for hierarchical encoding in inferior-temporal cortex.
    The twelfth annual computational neuroscience meeting.
    Alicante, Spain, July 2003.
    Proceedings will appear in Neurocomputing.
  1. Tatsuto Murayama and Masato Okada:
    A statistical-mechanical construction of the rate-distortion function for a binary source.
    Proceedings of 2003 IEEE International Symposium on Information Theory, July 2003
  1. Yoichi Miyawaki and Masato Okada:
    Computational model of transcranial magnetic stimulation (TMS): temporal property and subthreshold prolongation of visual suppression induced by neural population.
    Vision Sciences Society, 3rd Annual Meeting Vision Sciences 2003 (VSS*2003), p.207
  1. Tatsuto Murayama and Masato Okada:
    Rate distortion function in the spin glass state: a toy model.
    A Neural Information Processing Systems (NIPS*2002).
    Vancouver, British Columbia, Canada, Dec 2002.
  1. Jun Tsuzurugi and Masato Okada:
    Bayesian image restoration under spatially correlated noise -statistical-mechanical approach-
    Proceedings of 9th International Conference on Neural Information Processing (ICONIP'02 Singapore), 5(5), 2419- 2423, 2002.
  1. Kazuyuki Hara and Masato Okada:
    @@On-line learning through simple perceptron learning with margin
    Proceedings of 9th International Conference on Neural Information Processing (ICONIP'02 Singapore), 1(5), 158-164, 2002.
  1. Seiji Miyoshi, Hiro-Fumi Yanai and Masato Okada:
    Associative memory by recurrent neural networks with delay elements.
    Proceedings of 9th International Conference on Neural Information Processing (ICONIP'02 Singapore), 1(5), 70- 74, 2002.
  1. Seiji Miyoshi and Masato Okada:
    A theory of associative memory model with synaptic delay and pruning.
    Proceedings of Symposium on Nonlinear & Linear Information Processing Systems (NLIPS2002 Nagaoka), 1(1), 44- 51, 2002.
  1. Toru Aonishi and Masato Okada:
    Dendritic backpropagation of action potential induces bistability.
    Society for Neuroscience 32nd Annual Meeting, 753.6, 2002.
  1. Masami Tatsuno and Masato Okada:
    Possible neural mechanisms underlying information - geometric measure parameters.
    Society for Neuroscience 32nd Annual Meeting, 678.15, 2002.
  1. Koji Wada, Koji Kurata and Masato Okada:
    Self-organization of globally continuous and locally distributed information representation in the IT cortex.
    Society for Neuroscience 32nd Annual Meeting, 160.17, 2002.
  1. Masami Tatsuno and Masato Okada:
    How information-geometric measure depends on underlying neural mechanism?
    The eleventh annual computational neuroscience meeting (CNS 2002)
    Proceedings in Neurocomputing, 52-54, 649-654, 2003.
  1. Yoichi Miyawaki and Masato Okada:
    A network model of inhibitory effects induced by transcranial magnetic stimulation.
    The eleventh annual computational neuroscience meeting (CNS 2002)
    Proceedings in Neurocomputing, 52-54, 837-842, 2003.
  1. Hayaru Shouno and Masato Okada:
    Analysis of Bidirectional Associative Memory using SCSNA and Statistical Neurodynamics.
    Proceedings of the International Conference on Parallel and Distributed Processing Techniques and Applications, 1. 239-245, 2002.
  1. Narihisa Matsumoto and Masato Okada:
    Self-regulation mechanism of temporally asymmetric Hebbian plasticity.
    Neural Information Processing Systems (NIPS*2001)
    Vancouver, British Columbia, Canada, Dec 2001.
    Neural Information Processing Systems, 14, 245-252, 2002.
  1. Hayaru Shouno and Masato Okada:
    Statistical-mechanical approach for analog neural network model used in image restoration.
    Proceedings of the International Conference on Parallel and Distributed Processing Techniques and Applications, 3, 1298-1304, 2001.
  1. Masaki Kawamura, Masato Okada and Yuzo Hirai:
    Analysis of correlation-type associative memory with one-to-many associations.
    Proceedings of the 1997 International Conference on Neural Information and Intelligent Information Systems (ICONIP'97 New Zealand), 2(2), 885- 889, 1997.
  1. Hayaru Shouno, K. Nagahara, Kunihiko Fukushima and Masato Okada:
    Handwritten digits recognition with a neocognitron using different thresholds in learning and recognition.
    Proceedings of the 1996 International Conference on Neural Information and Intelligent Information Systems (ICONIP'96 Hong Kong), 1, 894- 899, 1996.
  1. Kunihiko Fukushima, K. Nagahara, Hayaru Shouno and Masato Okada:
    Training neocognitron to recognize handwritten digits in the real world.
    WCNN'96(World Congress on Neural Networks), 21-24, 1996.
  1. Kunihiko Fukushima, K. Nagahara, Hayaru Shouno and Masato Okada:
    Neural network model recalling spatial maps.
    Artificial Neural Networks - ICANN96, 1996.
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[Curriculum Vitae]

November 2002-October 2005   Researcher, "Intelligent Cooperation and Control", PRESTO, JST
April 2001-   Deputy Laboratory Head, RIKEN Brain Science Institute, Lab. for Mathematical Neuroscience
October 1996-March 2001   Researcher, Kawato Dynamic Brain Project, ERATO, JST
January 1997   Ph. D. from Osaka University Graduate School of Engineering Science
April 1991-September 1996   Research associate at K. Fukushima laboratory Department of Biophysical Engineering, Osaka University
April 1989-March 1991   Osaka University Graduate School of Engineering Science, Department of Biophysical Engineering
April 1987-March 1989   Mitsubishi Electric Corporation
April 1985-March 1987   Osaka University Graduate School of Science, Department of Physics
April 1981-March 1985   Osaka City University, Department of Physics
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[Awards]

  1. The 17th AVIRG (Audio-Visual Information Research Group) award.
  1. Award for encouragement of young scientist from department of biological and physiological engineering, Society of Instrument and Control Engineers (SICE) in 1997.
  1. Award for encouragement of young scientist from Japanese Neural Network Society (JNNS) in 1996.
  1. Best research award from JNNS in 1995.
  1. Best research award from JNNS in 1993.

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[Academic Activities]

Affiliated Institutes
  • The Institute of Electronics, Information and Communication Engineers
  • The Society of Instrument and Control Engineers
  • Japanese Neural Network Society
  • The Physical Society of Japan
  • Japan Neuroscience Society
  • Society for Neuroscience
  • Activities in the Affiliated Institutes
  • The Institute of Electronics, Information and Communication Engineers (IEICE)
    1. Secretary of Neurocomputing Technical Group, IEICE, (May 2003 - May 2005)
    1. Editorial Board Member of The IEICE Transactions (D-U), (May 2002 - May 2006)
    1. Review Committee Member of The IEICE Transactions (D-U), (May 1995 -)
    1. Assistant Secretary of Neurocomputing Technical Group, IEICE,(May 1994 - May 1997)

  • Japanese Neural Network Society
    1. Program Committee Member of The 14th National Convention of Japanese Neural Network Society 2003
    1. Program Committee Member of The 13th National Convention of Japanese Neural Network Society 2002
    1. Program Committee Member of The 12th National Convention of Japanese Neural Network Society 2001
    1. Director of Japanese Neural Network Society, (January 2000 - December 2001)
    Other Activities
    1. ICANN(International Conference of Artificial Neural Networks) 2002 Program committee

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    [Research Grants]

    Recent Research Grants (received in the past 5 years)

    1. Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology (PRESTO), "Intelligent Cooperation and Control"
    2. General Director : Yasuji Sawada (Professor at Tohoku Institute of Technology)
      Researcher : Masato Okada (Deputy Head of Laboratory for Mathematical Neuroscience RIKEN Brain Science Institute)
      Title of Project : Spike variability and functional architecture in the brain.
    1. Grant-in-Aid for Scientific Research in Fiscal Year 2002-2005
    2. Subject for Research : Grant-in-Aid for Scientific Research on Priority Areas (2)
      Project Number : 14084212
      Title of Project : Statistical mechanical approach to probabilistic information processing.
      Head Researcher : Masato Okada (Deputy Head of Laboratory for Mathematical Neuroscience RIKEN Brain Science Institute)
    1. Grant-in-Aid for Scientific Research in Fiscal Year 2002-2003
    2. Subject for Research : Grant-in-Aid for Scientific Research (C)(2)
      Project Number : 14580438
      Title of Project : Gaussian process function approximation and Bayesian image restoration.
      Head Researcher : Masato Okada (Deputy Head of Laboratory for Mathematical Neuroscience RIKEN Brain Science Institute)
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    [Contact]

    Address:@Kashiwa-campus of the University of Tokyo, Kashiwanoha 5-1-5 Kashiwa Chiba, 277-8561 JAPAN,
    E-mail:   TEL: YET AVAILABLE   FAX: YET AVAILABLE
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