Registered Data

[CT053]

  • Session Time & Room
    • CT053 (1/1) : 2E @G709 [Chair: Shousuke Ohmori]
  • Classification
    • CT053 (1/1) : Approximation methods and numerical treatment of dynamical systems (37M) / Hyperbolic equations and hyperbolic systems (35L)

[00442] On the dynamical properties of a max-plus model identified with the Lozi map

  • Session Time & Room : 2E (Aug.22, 17:40-19:20) @G709
  • Type : Contributed Talk
  • Abstract : We focus on a max-plus discretized model that is identified with the Lozi map in this talk. The max-plus model can be derived from the generalized Sel’kov model composed of non-linear differential equations via tropical discretization and ultradiscretization. Based on the Poincare mapping method and the estimation of Lyapunov exponents, the dynamical properties of the max-plus model and its transformation from the generalized Sel’kov model are discussed.
  • Classification : 37M20, 37M15, 65P40, 68Q80, 37J70
  • Format : Talk at Waseda University
  • Author(s) :
    • Shousuke Ohmori (Waseda University)
    • Yoshihiro Yamazaki (Waseda University)

[00457] On limit cycles of discrete dynamical systems with positivity

  • Session Time & Room : 2E (Aug.22, 17:40-19:20) @G709
  • Type : Contributed Talk
  • Abstract : We focus on limit cycles of discretized Sel'kov model derived from continuous Sel'kov model via tropical discretization. The discretized model possesses a parameter for time step. We numerically found, by varying the parameter, that density profile of phase in the limit cycles transits between continuous and ultradiscrete, and that the ultradiscrete state corresponds to a max-plus dynamical system. In this talk, we discuss these findings from the viewpoint of nonlinear dynamical systems.
  • Classification : 37M20, 37M15, 65P40, 68Q80, 37J70, ultradiscretization, max-plus dynamical system, bifurcation
  • Format : Talk at Waseda University
  • Author(s) :
    • Yoshihiro Yamazaki (Waseda University)
    • Shousuke Ohmori (Waseda University)

[01239] Convergence analysis of the discrete consensus-based optimization algorithm

  • Session Time & Room : 2E (Aug.22, 17:40-19:20) @G709
  • Type : Contributed Talk
  • Abstract : We study stochastic convergence of the discrete Consensus-Based Optimization, called CBO algorithm, in almost-sure sense and in expectation. CBO is a mathematical toy example for non-gradient multi-point optimizer which tries to find the global minimum point of a given cost function. The convergence analysis guarantees the termination of the optimization process. The main result is a joint work with Seung-Yeal Ha, Shi Jin, and Doheon Kim.
  • Classification : 37M99, 65p99
  • Format : Talk at Waseda University
  • Author(s) :
    • Dongnam Ko (The Catholic University of Korea)

[00456] Network representations of attractors for surrogates generation and change detection

  • Session Time & Room : 2E (Aug.22, 17:40-19:20) @G709
  • Type : Contributed Talk
  • Abstract : Attractors arising from delay embedded time-series can characterise system dynamics. However, extracting useful representations is challenging for systems with high-dimensional or complex structure. We propose a data-driven method to represent attractors as networks, where dynamics are encoded as node transition probabilities. The usefulness of this representation is demonstrated in two tasks: (1) surrogate data generation; and (2) change point detection. These methods are applied to chaotic time-series, and experimental ECG data for heart attack detection.
  • Classification : 37M10, 37M22, 94C12
  • Format : Talk at Waseda University
  • Author(s) :
    • Eugene Tan (The University of Western Australia)
    • Shannon Dee Algar (The University of Western Australia)
    • Debora Correa (The University of Western Australia)
    • Thomas Stemler (The University of Western Australia)
    • Michael Small (The University of Western Australia)

[00943] Similarity solutions for cylindrical shock wave in self-gravitating non-ideal gas with axial magnetic field: Isothermal flow

  • Session Time & Room : 2E (Aug.22, 17:40-19:20) @G709
  • Type : Contributed Talk
  • Abstract : The solution using the Lie group of symmetry method for the problem of propagating magnetogasdynamic strong cylindrical shock wave in a self-gravitating non-ideal gas with the axial magnetic field for isothermal flow. Numerical computations were performed for power law and exponential law shock paths, to see the behaviour of flow variables. The study provides how the variations in the various parameter taken in this study affect the propagation of shock and the flow behind it.
  • Classification : 35L45, 58J45, 35L67, 35Q35, 76L05, Fluid Mechanics
  • Format : Talk at Waseda University
  • Author(s) :
    • Nandita . (Dept. of Applied Mathematics & Scientific Computing, IIT Roorkee, Roorkee,India 247667)