Updated on 2024/10/07

Information

 

写真a

 
MORI FUMITO
 
Organization
Faculty of Agriculture Department of Bioresource Sciences Associate Professor
Title
Associate Professor
External link

Degree

  • PhD

Research Interests・Research Keywords

  • Research theme: Information flows in complex networks, Period variability of noisy oscillations

    Keyword: Complex networks, Information flows, Biological rhythms, Synchronization

    Research period: 2019.4

Papers

  • Information-transfer characteristics in network motifs

    Fumito Mori, Takashi Okada

    Physical Review Research   2023.1

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

    DOI: 10.1103/PhysRevResearch.5.013037

  • Noninvasive inference methods for interaction and noise intensities of coupled oscillators using only spike time data Reviewed

    Fumito Mori, Hiroshi Kori

    Proceedings of the National Academy of Sciences   119 ( 6 )   e2113620119 - e2113620119   2022.2

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

    Measurements of interaction intensity are generally achieved by observing responses to perturbations. In biological and chemical systems, external stimuli tend to deteriorate their inherent nature, and thus, it is necessary to develop noninvasive inference methods. In this paper, we propose theoretical methods to infer coupling strength and noise intensity simultaneously in two well-synchronized noisy oscillators through observations of spontaneously fluctuating events such as neural spikes. A phase oscillator model is applied to derive formulae relating each of the parameters to spike time statistics. Using these formulae, each parameter is inferred from a specific set of statistics. We verify these methods using the FitzHugh–Nagumo model as well as the phase model. Our methods do not require external perturbations and thus can be applied to various experimental systems.

    DOI: 10.1073/pnas.2113620119

  • Diagrammatic expansion of information flows in stochastic Boolean networks Reviewed

    Fumito Mori, Takashi Okada

    Physical Review Research   2 ( 4 )   2020.12

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

    DOI: 10.1103/physrevresearch.2.043432

  • Expected Number of Fixed Points in Boolean Networks with Arbitrary Topology Reviewed

    Fumito Mori, Atsushi Mochizuki

    PHYSICAL REVIEW LETTERS   119 ( 2 )   2017.7

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    Boolean network models describe genetic, neural, and social dynamics in complex networks, where the dynamics depend generally on network topology. Fixed points in a genetic regulatory network are typically considered to correspond to cell types in an organism. We prove that the expected number of fixed points in a Boolean network, with Boolean functions drawn from probability distributions that are not required to be uniform or identical, is one, and is independent of network topology if only a feedback arc set satisfies a stochastic neutrality condition. We also demonstrate that the expected number is increased by the predominance of positive feedback in a cycle.

    DOI: 10.1103/PhysRevLett.119.028301

  • Necessary Condition for Frequency Synchronization in Network Structures Reviewed

    Fumito Mori

    PHYSICAL REVIEW LETTERS   104 ( 10 )   2010.3

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    We present the necessary condition for complete frequency synchronization of phase-coupled oscillators in network structures. The surface area of a set of sites is defined as the number of links between the sites within the set and those outside the set. The necessary condition is that the surface area of any set of cN (0 < c < 1) oscillators in the N-oscillator system must exceed root N in the limit N -> infinity. We also provide the necessary condition for macroscopic frequency synchronization. Thus, we identify networks in which one or both of the above mentioned types of synchronization do not occur.

    DOI: 10.1103/PhysRevLett.104.108701

  • Maximisation of synchronisability under low injection power

    Hisa Aki Tanaka, Yoji Yabe, Somei Suga, Akira Keida, Kai Maeda, Fumito Mori, Hiroo Sekiya

    EPL   146 ( 5 )   2024.6   ISSN:0295-5075 eISSN:1286-4854

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    Publishing type:Research paper (scientific journal)   Publisher:EPL  

    Synchronisability of limit cycle oscillators has been measured by the width of the synchronous frequency band, known as the Arnold tongue, concerning external forcing. We clarify a fundamental limit on maximizing this synchronisability within a specified extra low power budget, which underlies an important and ubiquitous problem in nonlinear science related to an efficient synchronisation of weakly forced nonlinear oscillators. In this letter, injection-locked Class-E oscillators are considered as a practical case study, and we systematically analyse their power consumption; our observations demonstrate the independence of power consumption in the oscillator from power consumption in the injection circuit and verify the dependency of power consumption in the oscillator solely on its oscillation frequency. These systematic observations, followed by the mathematical optimisation establish the existence of a fundamental limit on synchronisability, validated through systematic circuit simulations. The results offer insights into the energetics of synchronisation for a specific class of injection-locked oscillators.

    DOI: 10.1209/0295-5075/ad4414

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  • Enhanced precision of circadian rhythm by output system Reviewed

    Hotaka Kaji, Fumito Mori, Hiroshi Ito

    Journal of Theoretical Biology   574   111621 - 111621   2023.10

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

    DOI: 10.1016/j.jtbi.2023.111621

  • Root PRR7 improves the accuracy of the shoot circadian clock through nutrient transport

    Kyohei Uemoto, Fumito Mori, Shota Yamauchi, Akane Kubota, Nozomu Takahashi, Haruki Egashira, Yumi Kunimoto, Takashi Araki, Atsushi Takemiya, Hiroshi Ito, Motomu Endo

    Plant and Cell Physiology   2023.1

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

    <jats:title>Abstract</jats:title>
    <jats:p>The circadian clock allows plants to anticipate and adapt to periodic environmental changes. Organ- and tissue-specific properties of the circadian clock as well as shoot-to-root circadian signaling have been reported. While this long-distance signaling is thought to coordinate physiological functions across tissues, little is known about the feedback regulation of root clock on the shoot clock in the hierarchical circadian network. Here, we show that the plant circadian clock conveys circadian information between shoots and roots through sucrose and K+. We also demonstrate that K+ transport from roots suppress the variance of period length in shoots and then improve the accuracy of shoot circadian clock. Sucrose measurements and qPCR showed that root sucrose accumulation was regulated by the circadian clock. Furthermore, root circadian clock genes, including PSEUDO-RESPONSE REGULATOR7 (PRR7), were regulated by sucrose, suggesting the involvement of sucrose from the shoot in the regulation of root clock gene expression. Therefore, we performed time-series measurements of xylem sap and micrografting experiments using prr7 mutants and showed that root PRR7 regulates K+ transport and suppresses variance of period length in the shoot. Our modeling analysis supports the idea that root-to-shoot signaling contributes to the precision of the shoot circadian clock. We performed micrografting experiments that illustrated how root PRR7 plays key roles in maintaining the accuracy of shoot circadian rhythms. We thus present a novel directional signaling pathway for circadian information from roots to shoots and propose that plants modulate physiological events in a timely manner through various timekeeping mechanisms.</jats:p>

    DOI: 10.1093/pcp/pcad003

  • Locking Range Maximization in Injection-Locked Class-E Oscillator—A Case Study for Optimizing Synchronizability Reviewed

    Yoji Yabe, Hisa-Aki Tanaka, Hiroo Sekiya, Masaki Nakagawa, Fumito Mori, Kensuke Utsunomiya, Akira Keida

    IEEE Transactions on Circuits and Systems I: Regular Papers   67 ( 5 )   1762 - 1774   2020.1

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    We propose a method for designing optimal external forcings of injection-locked oscillators. This method enables to maximize the locking range of general injection-locked oscillators under certain practical constraints that encompass the power, magnitude, or area of forcing waveforms. Here, as a case study, we focus on a class-E oscillator in the injection-locked mode, for which we obtain the following systematic results. First, by using the proposed method, the optimal waveform of external forcings is obtained analytically under three different constraints, i.e., the power-(i.e., root mean square-) reduced, magnitude-reduced, and area-reduced constraints. Second, through systematic circuit simulations, those predicted optimal forcings are verified to outperform any other forcings. Third, circuits experiments confirm that the theoretical predictions and the circuit simulation results are correct and consistent, regarding lock range maximization. These findings result in a first demonstration of locking range maximization for practical electrical oscillators.

    DOI: 10.1109/tcsi.2019.2960847

  • Synchronization of three electrochemical oscillators From local to global coupling Reviewed

    Yifan Liu, Michael Sebek, Fumito Mori, István Z. Kiss

    Chaos   28 ( 4 )   2018.4

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    We investigate the formation of synchronization patterns in an oscillatory nickel electrodissolution system in a network obtained by superimposing local and global coupling with three electrodes. We explored the behavior through numerical simulations using kinetic ordinary differential equations, Kuramoto type phase models, and experiments, in which the local to global coupling could be tuned by cross resistances between the three nickel wires. At intermediate coupling strength with predominant global coupling, two of the three oscillators, whose natural frequencies are closer, can synchronize. By adding even a relatively small amount of local coupling (about 9%-25%), a spatially organized partially synchronized state can occur where one of the two synchronized elements is in the center. A formula was derived for predicting the critical coupling strength at which full synchronization will occur independent of the permutation of the natural frequencies of the oscillators over the network. The formula correctly predicts the variation of the critical coupling strength as a function of the global coupling fraction, e.g., with local coupling the critical coupling strength is about twice than that required with global coupling. The results show the importance of the topology of the network on the synchronization properties in a simple three-oscillator setup and could provide guidelines for decrypting coupling topology from identification of synchronization patterns.

    DOI: 10.1063/1.5012520

  • Precision of collective oscillations in complex dynamical systems with noise Reviewed International journal

    Fumito Mori, Alexander S. Mikhailov

    PHYSICAL REVIEW E   93 ( 6 )   2016.6

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    Two kinds of oscillation precision are investigated for complex oscillatory dynamical systems under action of noise. The many-cycle precision determined by the variance of the times needed for a large number of cycles is closely related to diffusion of the global oscillation phase and provides an invariant property of a system. The single-cycle precision given by the variance in durations of single cycles is sensitive to the choice of an output variable and output checkpoint; it can be improved by an appropriate selection of them. A general analysis of the precision properties based on the Floquet perturbation theory is performed and analytical predictions are verified in numerical simulations of a model oscillatory genetic network.

    DOI: 10.1103/PhysRevE.93.062206

  • Period variability of coupled noisy oscillators Reviewed

    Fumito Mori, Hiroshi Kori

    Physical Review E - Statistical, Nonlinear, and Soft Matter Physics   87 ( 3 )   2013.3

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    Period variability, quantified by the standard deviation (SD) of the cycle-to-cycle period, is investigated for noisy phase oscillators. We define the checkpoint phase as the beginning or end point of one oscillation cycle and derive an expression for the SD as a function of this phase. We find that the SD is dependent on the checkpoint phase only when oscillators are coupled. The applicability of our theory is verified using a realistic model. Our work clarifies the relationship between period variability and synchronization from which valuable information regarding coupling can be inferred.

    DOI: 10.1103/PhysRevE.87.030901

  • Synchronization of coupled oscillators on small-world networks Reviewed

    Fumito Mori, Takashi Odagaki

    Physica D: Nonlinear Phenomena   238 ( 14 )   1180 - 1185   2009.7

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    We investigate the synchronous dynamics of Kuramoto oscillators and van der Pol oscillators on Watts-Strogatz type small-world networks. The order parameters to characterize macroscopic synchronization are calculated by numerical integration. We focus on the difference between frequency synchronization and phase synchronization. In both oscillator systems, the critical coupling strength of the phase order is larger than that of the frequency order for the small-world networks. The critical coupling strength for the phase and frequency synchronization diverges as the network structure approaches the regular one. For the Kuramoto oscillators, the behavior can be described by a power-law function and the exponents are obtained for the two synchronizations. The separation of the critical point between the phase and frequency synchronizations is found only for small-world networks in the theoretical models studied.

    DOI: 10.1016/j.physd.2009.04.002

  • The Laplacian spectra of small-world networks Reviewed

    F Mori, T Odagaki

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   73 ( 12 )   3294 - 3298   2004.12

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    Spectral properties of the Laplacian operator are studied numerically on the Watts-Strogatz-type small-world networks. The spectra on small-world networks are shown to have the characteristics that (i) the gap between the lowest frequency mode (Goldstone mode) and the second lowest frequency mode is small in contrast to that of random networks and (ii) the average participation ratio is as small as that of random networks. We also find that the highest frequency is essentially determined by the largest coordination degree.

    DOI: 10.1143/JPSJ.73.3294

  • Percolation analysis of clusters in random graphs Reviewed

    F Mori, T Odagaki

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   70 ( 8 )   2485 - 2489   2001.8

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    Percolation in random graphs is studied numerically. The strength of the largest cluster, the mean cluster size and the number of clusters are examined and the critical exponents of these quantities are shown to coincide with the classical values for percolation.

    DOI: 10.1143/JPSJ.70.2485

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Presentations

  • 概日時計出力系は時計を正確にし得る

    #梶穂高、@森史、@伊藤浩史

    第29回日本時間生物学会学術大会  2022.12 

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    Event date: 2022.12

    Language:Japanese  

    Venue:宇都宮   Country:Japan  

  • 振動の時刻データを用いた振動子間の結合強度の推定

    森史

    研究集会:データサイエンスにおける統計科学  2022.11 

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    Event date: 2022.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:九州大学   Country:Japan  

  • Output systems can improve accuracy of biological rhythms International conference

    #Hotaka Kaji, @Fumito Mori, and @Hiroshi Ito

    Conference on complex systems 2022  2022.10 

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    Event date: 2022.10

    Language:English  

    Venue:Palma, Spain   Country:Spain  

  • Graphical expansion of information flows in network motifs International conference

    Fumito Mori

    Conference on complex systems 2022  2022.10 

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    Event date: 2022.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Palma, Spain   Country:Spain  

  • 概日リズムの出力系のゆらぎ

    梶穂高、森史、伊藤浩史

    第127回日本物理学会九州支部例会  2021.12 

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    Event date: 2021.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  • 同期している振動子間の非対称な結合強度の推定

    森史、岩見貴弘、郡宏、伊藤浩史

    第127回日本物理学会九州支部例会  2021.12 

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    Event date: 2021.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  • Which clock is master? : inference of asymmetric interaction intensities in coupled oscillators

    森史 岩見貴弘 郡宏 伊藤浩史

    第28回 時間生物学会 学術大会  2021.11 

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    Event date: 2021.11

    Language:Japanese  

    Country:Japan  

  • 振動子間の非対称な結合強度をスパイク時刻データだけから推定する

    森史、岩見貴弘、郡宏、伊藤浩史

    日本物理学会 2021年秋季大会  2021.9 

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    Event date: 2021.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  • Does synchronization improve precision of biological oscillations?

    森 史

    第27回日本時間生物学会学術大会  2020.9 

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    Event date: 2021.5

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  • ブーリアンネットワークにおける移動エントロピーのダイアグラム展開

    森史, 岡田崇

    日本物理学会第76回年次大会  2021.3 

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    Event date: 2021.5

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  • ブーリアンネットワーク上の情報流をダイアグラムで展開する理論

    森史, 岡田崇

    第126回日本物理学会九州支部例会  2020.12 

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    Event date: 2021.5

    Language:Japanese  

    Country:Japan  

  • Fixed Points and Information Flow in Boolean Networks International conference

    Fumito Mori

    SIAM Conference on Applications of Dynamical Systems  2019.5 

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    Event date: 2019.5

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Snowbird, Utah, USA   Country:United States  

  • Expected Number of Fixed Points in Boolean Networks with Arbitrary Topology International conference

    Fumito Mori

    Complex networks 2018  2018.12 

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    Event date: 2018.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Cambridge University, Cambridge, UK   Country:United Kingdom  

  • ブーリアンネットワークの固定点数の期待値の定理 Invited

    森史

    第23回交通流と自己駆動粒子系のシンポジウム  2017.12 

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    Event date: 2017.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:名古屋大学   Country:Japan  

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MISC

  • Maximization of Injection-Locking Ability under Low Injection Power

    慶田朗, 矢部洋司, 前多夏維, 菅聡明, 森史, 関屋大雄, 田中久陽

    電子情報通信学会論文誌 A(Web)   J107-A ( 3 )   2024   ISSN:1881-0195

  • Inference Methods for Interaction and Noise Intensities Using Only Spike-time Data on Coupled Oscillators

    Fumito Mori, Hiroshi Kori

    2013.8

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    Language:Others  

    Inference Methods for Interaction and Noise Intensities Using Only Spike-time Data on Coupled Oscillators
    We propose theoretical methods to infer coupling strength and noise intensity<br />
    simultaneously through an observation of spike timing in two well-synchronized<br />
    noisy oscillators. A phase oscillator model is applied to derive formulae<br />
    relating each of the parameters to some statistics from spike-time data. Using<br />
    these formulae, each parameter is inferred from a specific set of statistics.<br />
    We demonstrate the methods with the FitzHugh-Nagumo model as well as the phase<br />
    model. Our methods do not require any external perturbation and thus are ready<br />
    for application to various experimental systems.

Professional Memberships

  • The Physical Society of Japan

  • Japanese Society for Mathematical Biology

  • The Institute of Electronics, Information and Communication Engineers

  • Japanese Society for Chronobiology

Research Projects

  • 情報流のパス展開理論と神経ネットワーク活動計測に基づく生物の行動決定機構の解明

    Grant number:22K03453  2022 - 2024

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Authorship:Principal investigator  Grant type:Scientific research funding

  • 複雑ネットワーク上の情報の流れの理論構築と生物の環境適応機構の解明

    2019.4

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    Authorship:Principal investigator 

  • 複雑ネットワーク上の情報の流れの理論構築と生物の環境適応機構の解明

    Grant number:19K03663  2019 - 2021

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Authorship:Principal investigator  Grant type:Scientific research funding

  • 複雑ネットワーク上の情報の流れの理論構築と生物の環境適応機構の解明

    Grant number:19K03663  2019 - 2021

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Authorship:Principal investigator  Grant type:Scientific research funding

  • 振動子集団のネットワーク構造と同期ダイナミクスの関係を統一的に記述する理論の構築

    Grant number:11J11148  2011 - 2013

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Grant type:Scientific research funding

  • 振動子集団のネットワーク構造と同期ダイナミクスの関係を統一的に記述する理論の構築

    Grant number:11J11148  2011 - 2013

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for JSPS Fellows

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    Authorship:Principal investigator  Grant type:Scientific research funding

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Class subject

  • 非線形理論

    2022.6 - 2022.8   Summer quarter