Faculty Profiles - OHIRA Toru

Papers - OHIRA Toru

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Amplitude Enhancements through rewiring of a non-autonomous delay system Reviewed

Kenta Ohira, Toru Ohira, Hideki Ohira

Chaos: An Interdisciplinary Journal of Nonlinear Science Vol. 35 page： 041101 2025.4

Collective behaviors emerging from chases and escapes Invited Reviewed

Artifitial Life Robotics Vol. 29 page： 1 2024.1

Dynamics with Transient Resonating Oscillations Reviewed

Kenta Ohira and Toru Ohira

Journal of the Physical Society of Japan Vol. 92 ( 6 ) 2023.6

Solving a Delay Differential Equation through Fourier Transform Invited Reviewed

Kenta Ohira, Toru Ohira

Physics Letters A Vol. 531 page： 130138 2025.1

Transient Reviving Dynamics with an Exact Solution for Delay Differential Equations Invited Reviewed

Kenta Ohira and Toru Ohira

Journal of the Physical Society of Japan Vol. 93 ( 9 ) 2024.9

The mechanism of pattern transitions between formation and dispersion Invited Reviewed

Shin Nishihara and Toru Ohira

Journal of Theoretical Biology Vol. 581 page： 111736 2024.3

Pursuit and Evasion: from singles to groups Invited Reviewed

Sota Yoshihara, Toru Ohira

Sota Yoshihara and Toru Ohira Vol. 2207 page： 012014 2022.3

A simple model of on--demand transporter Invited Reviewed

Yuhei Okubo, Takashi Shimada, Toru Ohira

Proceedings of 40th JSST Annual International Conference on Simulation Technology page： 32 - 34 2021.9

Delayed Gambler's Ruin Invited Reviewed

Tomohisa Imai, Toru Ohira

Vol. 39 ( 4 ) page： 247 - 251 2020.12

Difficulty Levels of Mathematical Problems and Machine Learning Invited Reviewed

Yuto Toida, Toru Ohira

Vol. 12 ( 2 ) page： 49 - 53 2020.5

Zero-correlation entanglement Reviewed

Toru Ohira

Progress of Theoretical and Experimental Physics Vol. 2020 ( 1 ) 2020.1

Language：English Publishing type：Research paper (scientific journal)

© 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the Physical Society of Japan. We consider a quantum entangled state for two particles, each particle having two basis states, which includes an entangled pair of spin 1/2 particles. We show that, for any quantum entangled state vectors of such systems, one can always find a pair of observable operators X, Y with zero correlations (ψ|XY|ψ-ψ|X|ψ (ψ|Y|ψ= 0). At the same time, if we consider the analogous classical system of a "classically entangled" (statistically non-independent) pair of random variables taking two values, one can never have zero correlations (zero covariance, E[XY]-E[X]E[Y] = 0). We provide a general proof to illustrate the different nature of entanglements in classical and quantum theories.

DOI： 10.1093/ptep/ptz149

Scopus

Delayed gambler’s ruin Reviewed

Tomohisa Imai, Toru Ohira

Stability, Control and Application of Time-Delay Systems page： 333 - 347 2019.1

Language：Japanese Publishing type：Part of collection (book)

© 2019 Elsevier Inc. All rights reserved. We present here a new extended model of the gambler’s ruin problem by incorporating delays in receiving of rewards and paying of penalties. When there is a difference between two delays, an exact analysis of the ruin probability is difficult. We derive an approximate scheme to find an effective shift in the initial assets of the gambler. Through comparison against computer simulations, this approximation is shown to work for small differences between the two delays.

DOI： 10.1016/B978-0-12-814928-7.00016-0

Scopus

On statistical independence and no-correlation for a pair of random variables taking two values: Classical and quantum Reviewed

Toru Ohira

Progress of Theoretical and Experimental Physics Vol. 2018 ( 8 ) 2018.8

Language：Japanese Publishing type：Research paper (scientific journal)

© 2018 The Author(s). It is well known that when a pair of random variables is statistically independent, it has nocorrelation (zero covariance, E[XY]-E[X[E[Y] = 0), and that the converse is not true. However, if both of these random variables take only two values, no-correlation entails statistical independence.We provide here a general proof.We subsequently examine whether this equivalence property carries over to quantum mechanical systems.A counter-example is explicitly constructed to show that it does not. This observation provides yet another simple theorem separating classical and quantum theories.

DOI： 10.1093/ptep/pty086

Web of Science

Scopus

双方向白色化ニューラルネットワーク Reviewed

藤本勇希, 大平徹

電子情報通信学会論文誌 D Vol. J101-D ( 1 ) page： 202-210 2018.1

Delays in Gambler's Ruin and Random Relays

Ohira Toru

IFAC PAPERSONLINE Vol. 51 ( 14 ) page： 207-211 2018

A Neural Network Model with Bidirectional Whitening. Reviewed

Yuki Fujimoto,Toru Ohira

Artificial Intelligence and Soft Computing - 17th International Conference, ICAISC 2018, Zakopane, Poland, June 3-7, 2018, Proceedings, Part I page： 47-57 2018

A neural network model with bidirectional whitening Reviewed

Yuki Fujimoto, Toru Ohira

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) Vol. 10841 page： 47 - 57 2018

Language：English Publishing type：Research paper (international conference proceedings) Publisher：Springer Verlag

We present here a new model and algorithm which performs an efficient Natural gradient descent for multilayer perceptrons. Natural gradient descent was originally proposed from a point of view of information geometry, and it performs the steepest descent updates on manifolds in a Riemannian space. In particular, we extend an approach taken by the “Whitened Neural Networks” model. We make the whitening process not only in the feed-forward direction as in the original model, but also in the back-propagation phase. Its efficacy is shown by an application of this “Bidirectional Whitened Neural Networks” model to a handwritten character recognition data (MNIST data).

DOI： 10.1007/978-3-319-91253-0_5

Scopus

Group chase and escape model with chasers' interaction Reviewed

Takuya Saito, Tomomichi Nakamura, Toru Ohira

PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS Vol. 447 page： 172 - 179 2016.4

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Group chase and escape is a new direction of studying collective behaviors merged with the traditional mathematical problems of chases and escapes proposed by Kamimura and Ohira in 2010. In their model, the chasers recognize only the escapees and pursue the nearest neighbor escapee, and the escapees recognize only the chasers and flee from the nearest neighbor chaser. We call the basic moving rule the nearest opponent interaction (NOI) strategy. In this paper we introduce a new strategy in the model. It is a local interaction that the chasers do not get too close each other, where we call the chasers' local interaction (CLI) strategy. The result of comparisons of the two strategies shows that when the number of the chasers is relatively small compared to the number of the escapees, the trapping time by the CLI strategy is much shorter than that by the NOI strategy. On the other hand, when the number of the chasers is larger than that of the escapees, this advantage of the CLI strategy does not appear. Also, we find that although chasers form clusters (spatial aggregates of chasers) when we apply the NOI strategy, the clusters appear less when we apply the CLI strategy. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physa.2015.12.023

Web of Science

Chases and escapes, and optimization problems Reviewed

Toru Ohira, Tadaaki Hosaka, Tomoaki Nogawa

Artificial Life and Robotics Vol. 20 ( 3 ) page： 257 - 261 2015.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer-Verlag Tokyo

We propose a new approach for solving combinatorial optimization problem by utilizing the mechanism of chases and escapes, which has a long history in mathematics. In addition to the well-used steepest descent and neighboring search, we perform a chase-and-escape game on the ‘‘landscape’’ of the cost function. We have created a concrete algorithm for the Traveling Salesman Problem. Our preliminary test indicates a possibility that this new fusion of chases and escapes problem into combinatorial optimization search is fruitful.

DOI： 10.1007/s10015-015-0220-2

Web of Science

Scopus

Quantum Square Well Bound States Described by Equations with Non-Locality Reviewed

OHIRA Toru

Interdiscip Inf Sci Vol. 19 ( 1 ) page： 61-64 (J-STAGE)-64 2013.8

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Papers - OHIRA Toru