Subject of the halo-chaos control in beam transport networks （channels） has become a key concerned issue for many important applications of high-current proton beam since 1990＇. In this paper, the magnetic field ad...Subject of the halo-chaos control in beam transport networks （channels） has become a key concerned issue for many important applications of high-current proton beam since 1990＇. In this paper, the magnetic field adaptive control based on the neural network with time-delayed feedback is proposed for suppressing beam halo-chaos in the beam transport network with periodic focusing channels. The envelope radius of high-current proton beam is controlled to reach the matched beam radius by suitably selecting the control structure and parameter of the neural network, adjusting the delayed-time and control coefficient of the neural network.展开更多
After studying the effects of imitation on the mixed population of adaptive agents with different memories competing in a minority game, we have found that when the pure population lies in a crowded regime, the introd...After studying the effects of imitation on the mixed population of adaptive agents with different memories competing in a minority game, we have found that when the pure population lies in a crowded regime, the introduction of imitation can considerably improve cooperation among agents in a money market.展开更多
In this paper, we propose a new model of weighted small-world biological neural networks based on biophysical Hodgkin-Huxley neurons with side-restrain mechanism. Then we study excitement properties of the model under...In this paper, we propose a new model of weighted small-world biological neural networks based on biophysical Hodgkin-Huxley neurons with side-restrain mechanism. Then we study excitement properties of the model under alternating current （AC） stimulation. The study shows that the excitement properties in the networks are preferably consistent with the behavior properties of a brain nervous system under different AC stimuli, such as refractory period and the brain neural excitement response induced by different intensities of noise and coupling. The results of the study have reference worthiness for the brain nerve electrophysiology and epistemological science.展开更多
Beam halo-chaos is essentially a complex spatiotemporal chaotic motion in a periodic-focusing channel of a highpower linear proton accelerator. The controllability condition for beam halo-chaos is analysed qualitative...Beam halo-chaos is essentially a complex spatiotemporal chaotic motion in a periodic-focusing channel of a highpower linear proton accelerator. The controllability condition for beam halo-chaos is analysed qualitatively. A special nonlinear control method, i.e. the wavelet-based function feedback, is proposed for controlling beam halochaos. Particle-in-cell simulations are used to explore the nature of halo-chaos formation, which has shown that the beam hMo-chaos is suppressed effectively after using nonlinear control for the proton beam with an initial full Gaussian distribution. The halo intensity factor Hav is reduced from 14%o to zero, and the other statistical physical quantities of beam halo-chaos are more than doubly reduced. The potential applications of such nonlinear control in experiments are briefly pointed out.展开更多
The Kapchinsky Vladimirsky(K-V)beam through a hackle periodic-focusing magnetic field is studiedusing the particle-core model.The beam halo-chaos is found,and an idea of fraction power-law function controller ispropos...The Kapchinsky Vladimirsky(K-V)beam through a hackle periodic-focusing magnetic field is studiedusing the particle-core model.The beam halo-chaos is found,and an idea of fraction power-law function controller isproposed based on the mechanism of halo formation and the strategy of controlling halo-chaos.The method is appliedto the multi-particle simulation to control the halo.The numerical results show that the halo-chaos and its regenerationcan be eliminated effectively by using the fraction power-law function control method.At the same time,the radialparticle density is uniform at the beam's center as long as the control method and appropriate parameter are chosen.展开更多
We investigate numerically the influences of Gaussian white noise on the dynamical behaviors of power systems.The studied model is a three-bus system at some specific parameters,and it demonstrates a stable regime tha...We investigate numerically the influences of Gaussian white noise on the dynamical behaviors of power systems.The studied model is a three-bus system at some specific parameters,and it demonstrates a stable regime that is far from collapse.It is found that with the increasing noise intensityσ,power systems become unstable and fall into oscillations;asσis further increased,noise-induced voltage collapse in power systems takes place.Our results confirm that the presence of noise has a detrimental effect on power system operation.Furthermore,the possible mechanism behind the action of noise is addressed based on a dynamical approach where the bifurcation of the system is analyzed.Our results may provide useful information for avoiding instability problems in power systems.展开更多
We investigate how the random long-range interactions affect the synchronization features in networks of inertial ratchets,where each ratchet is driven by a periodic time-dependent external force,under the influence o...We investigate how the random long-range interactions affect the synchronization features in networks of inertial ratchets,where each ratchet is driven by a periodic time-dependent external force,under the influence of an asymmetric periodic potential.It is found that for a given coupling strength𝐶,the synchronization of the coupled ratchets is induced as the fraction of random long-range interactions𝑝increases and the ratchet networks reach full synchronization for a larger𝑝.It is also found that the system reaches synchronization more effectively for a stronger coupling strength.展开更多
Because a brain consists of tremendous neuronal networks with different neuron numbers ranging from tens to tens of thousands, we study the coherence resonance due to ion channel noises in globally coupled neuronal ne...Because a brain consists of tremendous neuronal networks with different neuron numbers ranging from tens to tens of thousands, we study the coherence resonance due to ion channel noises in globally coupled neuronal networks with different neuron numbers. We confirm that for all neuronal networks with different neuron numbers there exist the array enhanced coherence resonance and the optimal synaptic conductance to cause the maximal spiking coherence. Furthermoremore, the enhancement effects of coupling on spiking coherence and on optimal synaptic conductance are almost the same, regardless of the neuron numbers in the neuronal networks. Therefore for all the neuronal networks with different neuron numbers in the brain, relative weak synaptic conductance （0.1 mS/cm2） is sufficient to induce the maximal spiking coherence and the best sub-threshold signal encoding.展开更多
This article develops a discrete time dynamic feedback model of a congestion control system for a simple network with TCP Westwood （TCPW） connections and a single bottleneck link with random early detection （RED） ...This article develops a discrete time dynamic feedback model of a congestion control system for a simple network with TCP Westwood （TCPW） connections and a single bottleneck link with random early detection （RED） gateway. By using this model, the nonlinear dynamics of the TCPW/RED network are analyzed and its parameter sensitivities are studied. It is shown that periodic doubling bifurcation occurs when the RED control parameters or other parameters are varied. By theoretical analysis, the fixed point, the critical value of parameters and the nature of the bifurcation are determined. Moreover, by using bifurcation diagrams and Lyapunov exponent, the result of theoretical analysis is validated and the bifurcation and chaotic phenomena are numerically studied of the congestion control system with TCPW connections and RED gateway.展开更多
基金The project supported by the Key Projects of National Natural Science Foundation of China under Grant No. 70431002 and National Natural Science Foundation of China under Grants Nos. 70371068 and 10247005
文摘Subject of the halo-chaos control in beam transport networks （channels） has become a key concerned issue for many important applications of high-current proton beam since 1990＇. In this paper, the magnetic field adaptive control based on the neural network with time-delayed feedback is proposed for suppressing beam halo-chaos in the beam transport network with periodic focusing channels. The envelope radius of high-current proton beam is controlled to reach the matched beam radius by suitably selecting the control structure and parameter of the neural network, adjusting the delayed-time and control coefficient of the neural network.
基金Supported by the Special Fund for National Basic Research Major Project in China(973 Project)the National Basic Research Climbing-Up Project“Nonlinear Science”+2 种基金the National Natural Science Foundation of China under Grant Nos.19932020,19974039 and 59876039the Research Grant Council of the Hong Kong SAR Government under Grant Nos.CUHK4191/97P and CUHK4241/01Pthe China-Canada University Industry Partnership Program(CCUIPP-NSFC Grant No.70142005.)。
文摘After studying the effects of imitation on the mixed population of adaptive agents with different memories competing in a minority game, we have found that when the pure population lies in a crowded regime, the introduction of imitation can considerably improve cooperation among agents in a money market.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 70571017 and 10547004 and the Key Projects of National Natural Science Foundation of China under Grant No. 70431002
文摘In this paper, we propose a new model of weighted small-world biological neural networks based on biophysical Hodgkin-Huxley neurons with side-restrain mechanism. Then we study excitement properties of the model under alternating current （AC） stimulation. The study shows that the excitement properties in the networks are preferably consistent with the behavior properties of a brain nervous system under different AC stimuli, such as refractory period and the brain neural excitement response induced by different intensities of noise and coupling. The results of the study have reference worthiness for the brain nerve electrophysiology and epistemological science.
基金Supported by the National Natural Science Foundation of China under Grant Nos.19875080 and 70071047。
文摘Beam halo-chaos is essentially a complex spatiotemporal chaotic motion in a periodic-focusing channel of a highpower linear proton accelerator. The controllability condition for beam halo-chaos is analysed qualitatively. A special nonlinear control method, i.e. the wavelet-based function feedback, is proposed for controlling beam halochaos. Particle-in-cell simulations are used to explore the nature of halo-chaos formation, which has shown that the beam hMo-chaos is suppressed effectively after using nonlinear control for the proton beam with an initial full Gaussian distribution. The halo intensity factor Hav is reduced from 14%o to zero, and the other statistical physical quantities of beam halo-chaos are more than doubly reduced. The potential applications of such nonlinear control in experiments are briefly pointed out.
基金National Natural Science Foundation of China under Crant No.10247005the Natural Science Foundation of the Anhui Higher Education Institutions of China under Grant No.KJ2007B187the Scientific Research Foundation of China University Of Mining and Technology for the Young under Grant No.OK060119
文摘The Kapchinsky Vladimirsky(K-V)beam through a hackle periodic-focusing magnetic field is studiedusing the particle-core model.The beam halo-chaos is found,and an idea of fraction power-law function controller isproposed based on the mechanism of halo formation and the strategy of controlling halo-chaos.The method is appliedto the multi-particle simulation to control the halo.The numerical results show that the halo-chaos and its regenerationcan be eliminated effectively by using the fraction power-law function control method.At the same time,the radialparticle density is uniform at the beam's center as long as the control method and appropriate parameter are chosen.
基金Supported by the of National Natural Science Foundation of China under Grant Nos 50937001(Key Program),10947011,10862001 and 50877028Construction of Key Laboratories in Universities of Guangxi Province under Grant No 200912.
文摘We investigate numerically the influences of Gaussian white noise on the dynamical behaviors of power systems.The studied model is a three-bus system at some specific parameters,and it demonstrates a stable regime that is far from collapse.It is found that with the increasing noise intensityσ,power systems become unstable and fall into oscillations;asσis further increased,noise-induced voltage collapse in power systems takes place.Our results confirm that the presence of noise has a detrimental effect on power system operation.Furthermore,the possible mechanism behind the action of noise is addressed based on a dynamical approach where the bifurcation of the system is analyzed.Our results may provide useful information for avoiding instability problems in power systems.
基金by the National Natural Science Foundation of China under Grant Nos 50937001(Key Program)10862001 and 10947011,the Construction of Key Laboratories in Universities of Guangxi Province under Grant No 200912the Science Foundation of Huaqiao University(09BS104).
文摘We investigate how the random long-range interactions affect the synchronization features in networks of inertial ratchets,where each ratchet is driven by a periodic time-dependent external force,under the influence of an asymmetric periodic potential.It is found that for a given coupling strength𝐶,the synchronization of the coupled ratchets is induced as the fraction of random long-range interactions𝑝increases and the ratchet networks reach full synchronization for a larger𝑝.It is also found that the system reaches synchronization more effectively for a stronger coupling strength.
基金supported by the National Natural Science Foundation of China (Grant No.11065003)the Natural Science Foundation of Guangxi Zhuang Autonoomous Region,China (Grant No.2011GXNSFA018129)the Research Funding of Education Department of Guangxi Zhuang Autonoomous Region of China (Grant No.201012MS026)
文摘Because a brain consists of tremendous neuronal networks with different neuron numbers ranging from tens to tens of thousands, we study the coherence resonance due to ion channel noises in globally coupled neuronal networks with different neuron numbers. We confirm that for all neuronal networks with different neuron numbers there exist the array enhanced coherence resonance and the optimal synaptic conductance to cause the maximal spiking coherence. Furthermoremore, the enhancement effects of coupling on spiking coherence and on optimal synaptic conductance are almost the same, regardless of the neuron numbers in the neuronal networks. Therefore for all the neuronal networks with different neuron numbers in the brain, relative weak synaptic conductance （0.1 mS/cm2） is sufficient to induce the maximal spiking coherence and the best sub-threshold signal encoding.
基金supported by the National Natural Science Foundation of China (70571017)the Fund of High School Excellent Young Talents in Anhui Province (2009SQRZ021)
文摘This article develops a discrete time dynamic feedback model of a congestion control system for a simple network with TCP Westwood （TCPW） connections and a single bottleneck link with random early detection （RED） gateway. By using this model, the nonlinear dynamics of the TCPW/RED network are analyzed and its parameter sensitivities are studied. It is shown that periodic doubling bifurcation occurs when the RED control parameters or other parameters are varied. By theoretical analysis, the fixed point, the critical value of parameters and the nature of the bifurcation are determined. Moreover, by using bifurcation diagrams and Lyapunov exponent, the result of theoretical analysis is validated and the bifurcation and chaotic phenomena are numerically studied of the congestion control system with TCPW connections and RED gateway.
