Yoshifumi NISHIO - Profile on Academia.edu (original) (raw)

Papers by Yoshifumi NISHIO

This paper presents several phase synchronization phenomena on multi-state oscillators coupled by... more This paper presents several phase synchronization phenomena on multi-state oscillators coupled by inductors as a ring. Each oscillator circuit can individually behave some periodic oscillations (limit cycles) in the same parameters asynchronously. In this study, a coupled oscillator circuit which is composed by some oscillators is proposed and classification of phase synchronization modes is investigated. In numerical simulation, many types of phase synchronization modes are confirmed in the proposed systems.

Synchronization is common phenomenon in the field of natural science. It should be noted that mut... more Synchronization is common phenomenon in the field of natural science. It should be noted that mutual synchronization phenomenon of oscillators gives various phase states and there have been many investigations on these phenomenon. In previous study, we confirmed the basic synchronization of three oscillators with the same natural frequencies coupled by a resonator. In this study, we investigate oscillation frequency of resonator-coupling three oscillators to carried out the sychronization phenomenon in detail.

In this study, we investigate behaviors of two identical coupled Chua's circuits whose parameters... more In this study, we investigate behaviors of two identical coupled Chua's circuits whose parameters periodically varying in associated with each of the period of internal state values. For the periodically varying of the parameters, odd-order cycles do not exist in this system. We observed coexistence of lots of attractors which have different orders of cycles and different synchronization states.

In this study, we propose two chaotic oscillators coupled via switch. The chaotic oscillators are... more In this study, we propose two chaotic oscillators coupled via switch. The chaotic oscillators are auto gain controlled oscillators containing time delay. The oscillators have feedback systems which control the gain. The coupling switch is placed between the feedback systems which control both of the oscillators. The coupling switch connects alternately with one subcircuit and the other with a fixed time interval. We carry out computer calculations and circuit experiments for two coupled auto gain controlled oscillators containing time delay and investigate synchronization phenomena. In the computer calculations, we observe coexistence phenomena of in-phase synchronization and opposite-phase synchronization. In the circuit experiments, we observe coexistence phenomena of in-phase quasi-synchronization and oppositephase quasi-synchronization. Finally, to investigate the difference between the numerical results and the experimental results, we investigate effects of parameter mismatch and noise.

Various synchronization phenomena in globally coupled parametrically forced logistic maps are obs... more Various synchronization phenomena in globally coupled parametrically forced logistic maps are observed for several coupling intensity when three maps are coupled. The synchronization phenomena fall into four general categories, which are asynchronous, self-switching of synchronization, synchronization of two among the three maps and synchronization of all the maps. In this study, we investigate the selfswitching phenomenon of synchronization in detail. In particular, relationship between sojourn time and the coupling intensity and condition that a synchronization state switch to other synchronization state are investigated.

A large number of coupled oscillators are useful as models for a wide variety of systems in natur... more A large number of coupled oscillators are useful as models for a wide variety of systems in natural fields. In this study, wave propagation generated in a ladder of cross-coupled chaotic circuits are investigated. For the case of 20 circuits, interesting wave propagation phenomena of phase states are found. Computer simulations show that this coupled system produces several wave propagation.

In our previous study, we observed the interesting phenomenon. It is that the synchronous rate of... more In our previous study, we observed the interesting phenomenon. It is that the synchronous rate of the whole system increases in spite of increasing parameter mismatches in the system. In this study, in order to verifier the this phenomenon, an asymmetrical coupled system is proposed and investigated. The system is realized by connecting chaotic subcircuits and van der Pol oscillators. In the case of five subcircuits, we confirmed synchronous phenomena in computer calculations. Additionally, It was confirmed that synchronous rates of chaotic subcircuits are increased by increasing a parameter mismatch rate of van der Pol oscillators. We consider that this result is corresponding to results of previous study.

In this study, the relation between synchronous rate and small variations on an asymmetrical coup... more In this study, the relation between synchronous rate and small variations on an asymmetrical coupled chaotic system is investigated. The system is realized by connecting one of two nodes in each chaotic subcircuit. The small variations are given to the subcircuit as an error of the oscillation frequency. In a computer calculation, an interesting phenomenon is observed. The phenomenon is that the synchronous rate of the whole system increases in spite of increasing parameter variations in the system.

In this study, two Chua's circuits with lossless transmission lines placed in parallel are invest... more In this study, two Chua's circuits with lossless transmission lines placed in parallel are investigated. The effect of the crosstalk is modeled by the connections via coupling capacitors or mutual inductors. By computer simulations, we confirm that two Chua's circuits are synchronized in in-pahse or anti-phase by the crosstalk effect of the transmission lines.

In this study, bifurcation and complex phenomena in synchronizing chaotic oscillators coupled by ... more In this study, bifurcation and complex phenomena in synchronizing chaotic oscillators coupled by a lossless transmission line are investigated. The period-doubling bifurcation with varying the time delay is observed in our circuit model. Further the voltage distribution of transmission line is simulated in order to investigate whether the current flowing through the transmission line is constant or not. It is found that the subsystems synchronize although the current through the transmission line keeps on varying.

IEICE Proceeding Series

In this study, synchronization phenomena observed from coupled van der Pol oscillators involving ... more In this study, synchronization phenomena observed from coupled van der Pol oscillators involving periodically forced capacitors are investigated. Firstly, we confirm effects of parametric excitation on synchronization. Next, we investigate behavior of parametric excitation in coupled system. By carrying out computer calculations for two to five subcircuits cases, various interesting synchronization phenomena of chaos are confirmed.

IEICE Proceeding Series

This paper considers the synchronization of coupled chaotic circuits with the parameter dispersio... more This paper considers the synchronization of coupled chaotic circuits with the parameter dispersion in three topologies obtained from the small-world network model. In particular, we focus on the parameter dispersion pattern based on the number of parameter mismatched circuits. By means of the computer calculations, the synchronization probabilities of each parameter dispersion pattern in three network topologies are investigated. From the simulation results, the small-world topology is shown to be effective for the synchronization in the entire network.

IEICE Proceeding Series

In our previous studies, the relationship between synchronization rates and small parameter misma... more In our previous studies, the relationship between synchronization rates and small parameter mismatches on an asymmetrical coupled chaotic systems has been investigated. As a result of investigating these systems, interesting phenomenon can be observed. We consider that the phenomenon can be observed in the case of any kinds of chaotic oscillators. In this study, a memristor based chaotic circuit are applied to our proposed system. By this investigation, our hypothesis for the phenomenon observed in our system is reinforced.

IEICE Proceeding Series

In this study, we investigate synchronization of parametrically excited van der Pol oscillators. ... more In this study, we investigate synchronization of parametrically excited van der Pol oscillators. In the case of two subcircuits, we confirm that the two subcircuits are synchronized at the opposite-phase without phase difference in the functions corresponding to the parametric excitation. In the case of three subcircuits, we confirm self-switching phenomenon of synchronization states.

IEICE Proceeding Series

ISCAS 2001. The 2001 IEEE International Symposium on Circuits and Systems (Cat. No.01CH37196)

An oscillator including a chaotic system is an important device and one of essential component in... more An oscillator including a chaotic system is an important device and one of essential component in the natural world to solve a mechanism of a nonlinear dynamics of network. In this study, a simple chaotic circuit with three states of both chaotic oscillation and limit cycles which is named multi-state chaotic circuit is proposed. Synchronization phenomena and complex behavior on a network system of the multi-state chaotic circuits coupled by inductors are investigated. Several interesting chaotic phenomena of spatio-temporal behavior have been observed in the coupled network system.

In this study, wave propagation phenomena of phase states are observed at van der Pol oscillators... more In this study, wave propagation phenomena of phase states are observed at van der Pol oscillators coupled by inductors as a ladder. For the case of 17 oscillators, interesting wave propagation phenomena of phase states are found. By using the relationship between phase states and oscillation frequencies, the mechanisms of the propagation and the reflection of wave are explained. Circuit experimental results agree well with computer calculated results qualitatively.

IEICE Proceeding Series

ISCAS 2001. The 2001 IEEE International Symposium on Circuits and Systems (Cat. No.01CH37196)