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1.
We propose an impulsive hybrid control method to control the
period-doubling bifurcations and stabilize unstable periodic orbits
embedded in a chaotic attractor of a small-world network. Simulation
results show that the bifurcations can be delayed or completely
eliminated. A periodic orbit of the system can be controlled to any
desired periodic orbit by using this method. 相似文献
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We investigate how dynamical behaviours of complex motor networks depend on the Newman-Watts small-world (NWSW) connections. Network elements are described by the permanent magnet synchronous motor (PMSM) with the values of parameters at which each individual PMSM is stable. It is found that with the increase of connection probability p, the motor in networks becomes periodic and falls into chaotic motion as p further increases. These phenomena imply that NWSW connections can induce and enhance chaos in motor networks. The possible mechanism behind the action of NWSW connections is addressed based on stability theory. 相似文献
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Bifurcation,chaotic phenomena and control of chaos in a one—dimensional discrete Josephson lattice
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We have investigated the fluxon dynamical behaviour in a one-dimensional parallel array of small Josephson junctions in the presence of an externally applied magnetic field. In the case of high damping,the system is in stable state. On the contrary, in the case of low damping, bifurcation and chaotic phenomena have been observed. Control of chaos is achieved by a delayed feedback mechanism, which drives the chaotic system into a selected unstable periodic orbit embadded within the associated strange attractor. It is attractive to control chaos to a periodic state, rather than operating always outside the device parameter space where chaos dominates. 相似文献
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研究了谐和激励下含有界随机参数Duffing系统(简称随机Duffing系统)中的随机混沌及其延迟反馈控制问题.借助Gegenbauer多项式逼近理论,将随机Duffing系统转化为与其等效的确定性非线性系统.这样,随机Duffing系统在谐和激励下的混沌响应及其控制问题就可借等效的确定性非线性系统来研究.分析阐明了随机混沌的主要特点,并采用Wolf算法计算等效确定性非线性系统的最大Lyapunov指数,以判别随机Duffing系统的动力学行为.数值计算表明,恰当选取不同的反馈强度和延迟时间,可分别达到抑制或诱发系统混沌的目的,说明延迟反馈技术对随机混沌控制也是十分有效的.
关键词:
随机Duffing系统
延迟反馈控制
随机混沌
Gegenbauer多项式 相似文献
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基于数学上延迟(时滞)系统Hopf分支理论及分析方法,解析地确定出 用延迟反馈法可控制三阶自治混沌系统的一般条件.利用这种分析方法,着重从理论上 讨论了在控制意义下系统出现稳定周期解及由Hopf分支产生周期解的分支方向的判据.将这 些理论应用到三阶自治混沌系统的控制实例中,解析地得到使系统可控的参量区域.在该区 域内选择控制参量,通过数值模拟也得到控制系统从混沌到周期态的结果.
关键词:
延迟反馈
Hopf分支
控制混沌 相似文献
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提出了基于稳定性准则的延迟非线性反馈控制混沌的方法,即SC延迟非线性反馈控制法. 通过对混沌系统的适当分离,得到一个特殊的非线性函数,并利用混沌输出信号与其延迟信号的非线性函数的差,构造了连续反馈输入干扰,以控制混沌轨到某一期望的不稳周期轨上. 该方法继承了延迟反馈控制方法的优点,实现了自-控制过程. 另外由于该方法基于线性系统的稳定性准则,保证了控制的有效性. 控制过程可随时开始,具有简便、灵活性. 给出耦合Duffing振子的例子,数值模拟结果显示了SC延迟反馈方法控制的有效性.
关键词:
稳定性准则
混沌控制
延迟反馈
干扰 相似文献
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In this paper, we propose a simple model that can generate
small-world network with community structure. The network is
introduced as a tunable community organization with parameter r,
which is directly measured by the ratio of inter- to intra-community
connectivity, and a smaller r corresponds to a stronger community
structure. The structure properties, including the degree
distribution, clustering, the communication efficiency and
modularity are also analysed for the network. In addition, by using
the Kuramoto model, we investigated the phase synchronization on
this network, and found that increasing the fuzziness of community
structure will markedly enhance the network synchronizability;
however, in an abnormal region (r ≤ 0.001), the network has even
worse synchronizability than the case of isolated communities (r =
0). Furthermore, this network exhibits a remarkable
synchronization behaviour in topological scales: the oscillators of
high densely interconnected communities synchronize more easily, and
more rapidly than the whole network. 相似文献
14.
Bifurcation control and the existence of chaos in a class of
linear impulsive systems are discussed by means of both theoretical
and numerical ways. Chaotic behaviour in the sense of Marotto's
definition is rigorously proven. A linear impulsive controller,
which does not result in any change in one period-1 solution of the
original system, is proposed to control and anti-control chaos. The
numerical results for chaotic attractor, route leading to chaos,
chaos control, and chaos anti-control, which are illustrated with
two examples, are in good agreement with the theoretical analysis. 相似文献
15.
Hybrid control of bifurcation and chaos in stroboscopic model of Internet congestion control system
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Interaction between transmission control protocol (TCP) and random
early detection (RED) gateway in the Internet congestion control
system has been modelled as a discrete-time dynamic system which
exhibits complex bifurcating and chaotic behaviours. In this paper, a
hybrid control strategy using both state feedback and parameter
perturbation is employed to control the bifurcation and stabilize the
chaotic orbits embedded in this discrete-time dynamic system of
TCP/RED. Theoretical analysis and numerical simulations show that the
bifurcation is delayed and the chaotic orbits are stabilized to a
fixed point, which reliably achieves a stable average queue size in
an extended range of parameters and even completely eliminates the
chaotic behaviour in a particular range of parameters. Therefore it
is possible to decrease the sensitivity of RED to parameters. By
using the hybrid strategy, we may improve the stability and
performance of TCP/RED congestion control system significantly. 相似文献
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Hybrid control of bifurcation and chaos in stroboscopic model of Internet congestion control system 总被引:1,自引:0,他引:1
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Interaction between transmission control protocol (TCP) and random early detection (RED) gateway in the Internet congestion control system has been modelled as a discrete-time dynamic system which exhibits complex bifurcating and chaotic behaviours. In this paper, a hybrid control strategy using both state feedback and parameter perturbation is employed to control the bifurcation and stabilize the chaotic orbits embedded in this discrete-time dynamic system of TCP/RED. Theoretical analysis and numerical simulations show that the bifurcation is delayed and the chaotic orbits are stabilized to a fixed point, which reliably achieves a stable average queue size in an extended range of parameters and even completely eliminates the chaotic behaviour in a particular range of parameters. Therefore it is possible to decrease the sensitivity of RED to parameters. By using the hybrid strategy, we may improve the stability and performance of TCP/RED congestion control system significantly. 相似文献
17.
In this study, the robustness of small-world networks to three types of attack is investigated. Global efficiency is introduced as the network coefficient to measure the robustness of a small-world network. The simulation results prove that an increase in rewiring probability or average degree can enhance the robustness of the small-world network under all three types of attack. The effectiveness of simultaneously increasing both rewiring probability and average degree is also studied, and the combined increase is found to significantly improve the robustness of the small-world network.Furthermore, the combined effect of rewiring probability and average degree on network robustness is shown to be several times greater than that of rewiring probability or average degree individually. This means that small-world networks with a relatively high rewiring probability and average degree have advantages both in network communications and in good robustness to attacks. Therefore, simultaneously increasing rewiring probability and average degree is an effective method of constructing realistic networks. Consequently, the proposed method is useful to construct efficient and robust networks in a realistic scenario. 相似文献
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根据实际生物神经网络具有小世界连接和神经元之间的连接强度随时间变化的特点,首先构造了一个以Hodgkin-Huxley方程为节点动力学模型的动态变权小世界生物神经网络模型,然后研究了该模型神经元的兴奋特性、权值变化特点和不同的学习系数对神经元的兴奋统计特性的影响.最有意义的结果是,在同样的网络结构、网络参数及外部刺激信号的条件下,学习系数b存在一个最优值b*,使生物神经网络的兴奋度在b=b*时达到最大.
关键词:
动态变权生物神经网络
小世界网络
Hodgkin-Huxley方程 相似文献
19.
以环型腔反馈激光系统为主,综述了非线性激光系统的混沌动力学特性;分析了延迟反馈方法控制混沌的原理和稳定性条件,实现了对多介质非线性激光系统中的混沌控制。同时概述了近年来非线性激光系统中混沌控制的最新进展,诸如空间小微扰法、偶然正比反馈技术等,讨论了混沌控制在提高激光器功率和性能、利用混沌进行秘密通讯和信息处理等方面的应用前景。 相似文献
20.
Control of chaos by a delayed continuous feedback is studied experimentally in a gas discharge plasma. The power spectrum, the maximum of Lyapunov exponents and the time series of the signals all indicate that the period-1 unstable periodic orbit is controlled successfully. The dependence of the control on the delay time and the feedback gain as well as the strength of white noise is also investigated in detail. The experimental results show that the scaling index of the control versus the strength of white noise is 1.995, which is very close to that obtained from the simple logistic map. 相似文献