Updated on 2025/02/05

写真a

 
TAGA, Keisuke
 
Affiliation
Faculty of Science and Engineering, Graduate School of Advanced Science and Engineering
Job title
Assistant Professor(non-tenure-track)
Degree
Doctor of Science ( 2023.06 Waseda University )

Research Experience

  • 2023.09
    -
    Now

    Waseda University   Graduate School of Advanced Science and Engineering   Assistant Professor (without tenure)

  • 2023.04
    -
    Now

    Tokyo Institute of Technology

  • 2023.04
    -
    2023.08

    Waseda University   School of Advanced Science and Engineering   Research associate

Education Background

  • 2020.04
    -
    2023.06

    Waseda University   Graduate School of Advanced Science and Engineering   Department of Pure and Applied Physics  

    Doctoral program

  • 2018.04
    -
    2020.03

    Waseda University   Graduate School of Advanced Science and Engineering   Department of Pure and Applied Physics  

    Master’s program

  • 2014.04
    -
    2018.03

    Waseda University   School of Advanced Science and Engineering   Department of Applied Physics  

Committee Memberships

  • 2024.10
    -
    2025.09

    日本物理学会  領域運営委員（領域11）

Professional Memberships

  • 2021
    -
    Now

    日本応用数理学会

  • 2018
    -
    Now

    日本物理学会

Research Areas

  • Applied mathematics and statistics / Biophysics, chemical physics and soft matter physics / Mathematical physics and fundamental theory of condensed matter physics

Research Interests

  • Nonequilibrium statistical mechanics

  • Dynamical system

Awards

  • SIAM Student Chapter Certificate of Recognition 2024

    2024.04   Society for Industrial and Applied Mathematics  

    Winner： Keisuke Taga

  • Presentation Awards for Young Scientists

    2018.12   International conference on Advances in Physics of Emergent orders in Fluctuations 2018   Mean-field analysis for Kuramoto model with general time delay

    Winner： Keisuke Taga

 

Papers

  • Dynamic mode decomposition for Koopman spectral analysis of elementary cellular automata

    Keisuke Taga, Yuzuru Kato, Yoshihiro Yamazaki, Yoshinobu Kawahara, Hiroya Nakao

    Chaos: An Interdisciplinary Journal of Nonlinear Science    2024.01  [Refereed]

    Authorship：Lead author

    　View Summary

    We apply Dynamic Mode Decomposition (DMD) to Elementary Cellular Automata
    (ECA). Three types of DMD methods are considered and the reproducibility of the
    system dynamics and Koopman eigenvalues from observed time series are
    investigated. While standard DMD fails to reproduce the system dynamics and
    Koopman eigenvalues associated with a given periodic orbit in some cases,
    Hankel DMD with delay-embedded time series improves reproducibility. However,
    Hankel DMD can still fail to reproduce all the Koopman eigenvalues in specific
    cases. We propose an Extended DMD method for ECA that uses nonlinearly
    transformed time series with discretized Walsh functions and show that it can
    completely reproduce the dynamics and Koopman eigenvalues. Linear-algebraic
    backgrounds for the reproducibility of the system dynamics and Koopman
    eigenvalues are also discussed.

    DOI

    Scopus

    1
    Citation
    (Scopus)

  • A Tape-Peeling Model for Spatiotemporal Pattern Formation by Deformed Adhesives

    Keisuke Taga, Yoshihiro Yamazaki

    Journal of the Physical Society of Japan    2023.04  [Refereed]

    Authorship：Lead author

    　View Summary

    We propose a new model for pattern formation in peeling of an adhesive tape
    based on the equation of motion for the displacement of deformed adhesives in
    the peel front. The spatiotemporal patterns obtained from the model are
    consistent with those from previous models and experiments. Moreover, dynamical
    and statistical properties of the patterns are investigated.

    DOI

    Scopus

    1
    Citation
    (Scopus)

  • Koopman spectral analysis of elementary cellular automata

    Keisuke Taga, Yuzuru Kato, Yoshinobu Kawahara, Yoshihiro Yamazaki, Hiroya Nakao

    Chaos   31 ( 10 )  2021.10  [Refereed]

    Authorship：Lead author

    　View Summary

    We perform a Koopman spectral analysis of elementary cellular automata (ECA).
    By lifting the system dynamics using a one-hot representation of the system
    state, we derive a matrix representation of the Koopman operator as a transpose
    of the adjacency matrix of the state-transition network. The Koopman
    eigenvalues are either zero or on the unit circle in the complex plane, and the
    associated Koopman eigenfunctions can be explicitly constructed. From the
    Koopman eigenvalues, we can judge the reversibility, determine the number of
    connected components in the state-transition network, evaluate the periods of
    asymptotic orbits, and derive the conserved quantities for each system. We
    numerically calculate the Koopman eigenvalues of all rules of ECA on a
    one-dimensional lattice of 13 cells with periodic boundary conditions. It is
    shown that the spectral properties of the Koopman operator reflect Wolfram's
    classification of ECA.

    DOI

    Scopus

    2
    Citation
    (Scopus)

Research Projects

  • テープの剥がし跡のパターン形成ダイナミクス

    日本学術振興会  科学研究費助成事業

    Project Year :

    2024.04
    -
    2028.03
     

    多賀 圭理

Misc

  • Universality in the tape-peeling trace

    Keisuke Taga, Akihiko Toda, Yoshihiro Yamazaki

       2024.12

    　View Summary

    Spatiotemporal patterns, which are of interest in statistical physics and
    nonlinear dynamics, form on the tape-peeling trace. Recently, we have proposed
    a mathematical model to describe these pattern formation in the tape-peeling
    trace. In this paper, we further investigate the tape-peeling model from the
    perspective of its universality class. We confirm that our model belongs to the
    1-dimensional directed percolation universality class. Furthermore, the
    experimental results from a previous study are re-analyzed, and it is suggested
    that the tape-peeling trace can also be classified within the 1-dimensional
    directed percolation universality class.

  • Dynamic Mode Decomposition for Elementary Cellular Automata

    Keisuke Taga, Hiroya Nakao

    IEICE Proceeding Series   71   117 - 120  2022.12

    　View Summary

    Dynamic mode decomposition (DMD) provides a data-driven approach to analyzing dynamical systems and has been applied to various systems. In this study, we performed DMD and Extended DMD analysis for elementary cellular automata (ECA) as a typical example of finite-state spatially-extended dynamical systems. ECA can exhibit various dynamics including chaotic ones, and thus be useful for examining the validity of the results obtained by DMD.

    DOI

  • エレメンタリーセルオートマトンのKoopmanスペクトル解析

    多賀圭理, 加藤譲, 河原吉伸, 河原吉伸, 山崎義弘, 中尾裕也

    日本応用数理学会年会講演予稿集(CD-ROM)   2021  2022

    J-GLOBAL

  • Statistical properties in score fluctuations of gateball

    山崎義弘, 成塚拓真, 香川渓一郎, 多賀圭理

    日本物理学会講演概要集(CD-ROM)   76 ( 1 )  2021

    J-GLOBAL

  • Peeling tape as a reaction-diffusion system

    多賀圭理, 山崎義弘

    日本物理学会講演概要集(CD-ROM)   75 ( 2 )  2020

    J-GLOBAL

  • 距離に比例した時間遅れを伴う蔵本モデルのダイナミクス

    多賀圭理, 山崎義弘

    日本物理学会講演概要集(CD-ROM)   74 ( 1 )  2019

    J-GLOBAL

  • 距離に依存した時間遅れを伴う蔵本モデルのダイナミクス II

    多賀圭理, 山崎義弘

    日本物理学会講演概要集(CD-ROM)   74 ( 2 )  2019

    J-GLOBAL

  • 一般的な時間遅れを持つ蔵本モデルの平均場解析

    多賀圭理, 山崎義弘

    日本物理学会講演概要集(CD-ROM)   73 ( 2 )  2018

    J-GLOBAL

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Syllabus

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Internal Special Research Projects

  • 粘着テープの剥がし跡のパターン形成とその数理構造

    2023   山崎義弘

    　View Summary

    粘着テープをはがす際，そのはがし跡にフラクタル的な興味深いパターンが表れることが知られている．また，剥がす速度を変化させることで，剥がし跡の性質が変化するという相転移的な性質が見られることも知られている．本研究では，そのパターン形成のメカニズムや性質を数理モデルを構築し，解析することで探索することを目的としている．本年度は[Taga and Yamazaki 2023]において提案したテープはがしモデルの数理的性質についての研究を行い下記の成果について国際学会IUTAM Symposiumのプロシーディング1本，statphysなどの国際研究会3回，国内研究会1回で発表した．1. 物理的性質数値シミュレーションを行い，数理モデルが実験結果における剥がし跡の形成や，剥がす速度に応じての剥がし跡の変化の仕方をよく再現することを確認した．2．数理的性質分岐解析を行い，提案した数理モデルの局所的なダイナミクスの性質の解析を行った．また，数理シミュレーションの結果，モデルが示すパターンにベキ的な性質が表れることを確認し，その検討を行った．3．先行モデルとの関連テープの剥がし跡の数理モデルは先行的にもいくつか提案されている．本研究で提案し，解析している数理モデルは先行研究とは異なる物理的メカニズムを有しているが，適当な変換を行うことで，ほかの数理モデルと見た形式を有することを指摘した．