arXiv subjects

Tsuyoshi Chawanya

Publications and source records attributed to Tsuyoshi Chawanya.

5 recordsLinked to original sources

arXiv2014

On repellers in quasi-periodically forced logistic map system

We propose a method to identify and to locate "repellers'' in quasi-periodically forced logistic map (QPLM), using a kind of Morse decomposition of nested attracting invariant sets. In order to obtain the invariant sets, we use an auxiliary 1+2-dimensional skew-product map system describing the evolution of a line segment in the phase space of QPLM. With this method, detailed structure of repellers can be visualized, and the emergence of a repeller in QPLM can be detected as an easily observable bifurcation in the auxiliary system. In addition to the method to detect the repellers, we propose a new numerical method for distinguishing a strange non-chaotic attractor (SNA) from a smooth torus attractor, using a correspondence between SNAs in QPLM and attractors with riddled basin in the auxiliary system.

nlin.CD↗

arXiv2001

Collective motions in globally coupled tent maps with stochastic updating

We study a generalization of globally coupled maps, where the elements are updated with probability $p$. When $p$ is below a threshold $p_c$, the collective motion vanishes and the system is the stationary state in the large size limit. We present the linear stability analysis.

nlin.CD↗

arXiv1998

Noiseless Collective Motion out of Noisy Chaos

We consider the effect of microscopic external noise on the collective motion of a globally coupled map in fully desynchronized states. Without the external noise a macroscopic variable shows high-dimensional chaos distinguishable from random motion. With the increase of external noise intensity, the collective motion is successively simplified. The number of effective degrees of freedom in the collective motion is found to decrease as $-\log{σ^2}$ with the external noise variance $σ^2$. It is shown how the microscopic noise can suppress the number of degrees of freedom at a macroscopic level.

chao-dyn↗

arXiv1995

A New Type of Irregular Motion in a Class of Game Dynamics Systems

A new type of asymptotic behavior in a game dynamics system is discovered. The system exhibits behavior which combines chaotic motion and attraction to heteroclinic cycles; the trajectory visits several unstable stationary states repeatedly with an irregular order, and the typical length of the stay near the steady states grows exponentially with the number of visits. The dynamics underlying this irregular motion is analyzed by introducing a dynamically rescaled time variable, and its relation to the low-dimensional chaotic dynamics is thus uncovered. The relation of this irregular motion with a strange type of instability of heteroclinic cycles is also examined.

chao-dyn↗

arXiv1994

Weakly Chaotic Population Dynamics in Random Ecological Networks

Population dynamics in random ecological networks are investigated by analyzing a simple deterministic equation. It is found that a sequence of abrupt changes of populations punctuating quiescent states characterize the long time behavior. An asymptotic analysis is developed by introducing a log-scaled time, and it is shown that such a dynamical process behaves as non-steady weak chaos in which population disturbances grow algebraically in time. Also, some relevance of our study to taxonomic data of biological extinction is mentioned.

chao-dyn↗