复合混沌系统的非线性动力学行为分析

从理论上研究了由几个混沌系统复合而构成的新系统的非线性动力学特性和分岔序列.计算机仿真与理论计算结果表明，复合混沌系统具有混沌吸引子和对初值敏感性，并且有缺边现象产生. 关键词： 复合系统 吸引子 分岔序列     

Multiphoton coherent control in complex systems

Control of multiphoton transitions is demonstrated for a multilevel system by generalizing the instantaneous phase of any chirped pulse as individual terms of a Taylor series expansion. In the case of a simple two-level system, all odd terms in the series lead to population inversion while the even terms lead to self-induced transparency. The results hold for multiphoton transitions that do not have any lower-order photon resonance or any intermediate virtual state dynamics within the laser pulse width.     

Entropy control in discrete-and continuous-time dynamic systems

The dynamics of a modified logistic mapping are considered for a system with the order parameter modulated by an external signal. It is shown that the Kolmogorov-Sinay entropy changes with changing modulation depth, while the harmonic signals and white noise can be used as a modulating signal. The conditions for the excitation of regular and strange nonchaotic attractors in the phase space are established.     

不确定动态混沌系统的最优控制

对于混沌系统的控制问题,考虑到控制系统能量限制的要求,首先确立一个二次目标函数,然后给出了求解最优控制律的一个简单方法,该方法通过求解线性二次最优控制问题,获得了混沌系统的最优控制律,避免了求解非线性Hamilton-Jacobi-Bellman 偏微分方程(HJB方程)的困难.利用Lyapunov方法证明了闭环系统的稳定性.对统一混沌系统和Liu混沌系统的仿真结果表明了控制策略的有效性.     

不确定动态混沌系统的最优控制

对于混沌系统的控制问题,考虑到控制系统能量限制的要求,首先确立一个二次目标函数,然后给出了求解最优控制律的一个简单方法,该方法通过求解线性二次最优控制问题,获得了混沌系统的最优控制律,避免了求解非线性Hamilton-Jacobi-Bellman偏微分方程(HJB方程)的困难.利用Lyapunov方法证明了闭环系统的稳定性.对统一混沌系统和Liu混沌系统的仿真结果表明了控制策略的有效性.     

Critical dynamic approach to stationary states in complex systems

A dynamic scaling Ansatz for the approach to stationary states in complex systems is proposed and tested by means of extensive simulations applied to both the Bak-Sneppen (BS) model, which exhibits robust Self-Organised Critical (SOC) behaviour, and the Game of Life (GOL) of J. Conway, whose critical behaviour is under debate. Considering the dynamic scaling behaviour of the density of sites (ρ(t)), it is shown that i) by starting the dynamic measurements with configurations such that ρ(t=0) →0, one observes an initial increase of the density with exponents θ= 0.12(2) and θ= 0.11(2) for the BS and GOL models, respectively; ii) by using initial configurations with ρ(t=0) →1, the density decays with exponents δ= 0.47(2) and δ= 0.28(2) for the BS and GOL models, respectively. It is also shown that the temporal autocorrelation decays with exponents C_a = 0.35(2) (C_a = 0.35(5)) for the BS (GOL) model. By using these dynamically determined critical exponents and suitable scaling relationships, we also obtain the dynamic exponents z = 2.10(5) (z = 2.10(5)) for the BS (GOL) model. Based on this evidence we conclude that the dynamic approach to stationary states of the investigated models can be described by suitable power-law functions of time with well-defined exponents.     

On the control of quantum statistical systems

The problem of preparing a system in some initial configuration is discussed for quantum statistical systems whose dynamics are generated by Markovian semigroups. The system is regulated by a set of controls and the central problem is to determine how the controls should be varied in order to bring the system as close as possible to the desired configuration in a fixed finite time. General equations are derived which allow one to determine how the controls should be regulated. The application of the result to a simple system is outlined.     

A dynamic epidemic control model on uncorrelated complex networks

In this paper, a dynamic epidemic control model on the uncorrelated complex networks is proposed. By means of theoretical analysis, we found that the new model has a similar epidemic threshold as that of the susceptible-infectedrecovered （SIR） model on the above networks, but it can reduce the prevalence of the infected individuals remarkably. This result may help us understand epidemic spreading phenomena on real networks and design appropriate strategies to control infections.     

Memory functions of the additive Markov chains: applications to complex dynamic systems

A new approach to describing correlation properties of complex dynamic systems with long-range memory based on a concept of additive Markov chains (Phys. Rev. E 68 (2003) 061107) is developed. An equation connecting the memory and correlation function of the system under study is presented. This equation allows reconstructing a memory function using a correlation function of the system. Effectiveness and robustness of the proposed method is demonstrated by simple model examples. Memory functions of concrete coarse-grained literary texts are found and their universal power-law behavior at long distances is revealed.     

On stochastic behaviour of multi-level dynamic quantum systems

Spectral properties of multi-level dynamic quantum systems in the case of destruction of integrals of motion are discussed. Main attention is paid to the problem of arising of stochasticity in the system of multi-level molecules interacting with the self-consistent radiation field.     

复杂Dynamos混沌系统的追踪控制与同步

基于系统稳定性理论,设计合适的新型非线性反馈控制器,实现复杂Dynamos混沌系统的状态向量与任意给定的不同参考信号追踪广义投影同步.以追踪控制超混沌系统、混沌系统、正弦余弦信号以及不动点为例,通过改变比例因子,可以获得多个不同混沌系统之间的异结构广义投影同步以及与正弦波形的广义同步,或者将复杂Dynamos混沌系统控制到期望的平衡点.数值仿真进一步表明了该方法的有效性. 关键词： 复杂Dynamos混沌系统 追踪控制 广义投影同步 平衡点     

复杂Dynamos混沌系统的追踪控制与同步

基于系统稳定性理论，设计合适的新型非线性反馈控制器，实现复杂Dynamos混沌系统的状态向量与任意给定的不同参考信号追踪广义投影同步.以追踪控制超混沌系统、混沌系统、正弦余弦信号以及不动点为例，通过改变比例因子，可以获得多个不同混沌系统之间的异结构广义投影同步以及与正弦波形的广义同步，或者将复杂Dynamos混沌系统控制到期望的平衡点.数值仿真进一步表明了该方法的有效性.     

On classification and special features of motion of dynamic systems

A number of debatable problems of modern nonlinear physics are discussed. A classification of deterministic systems with chaotic behavior by the degree of openness and type of motion is suggested. Examples of dynamic systems illustrating the consistency of this classification are presented, and special features of functioning of these systems and problems of quantitative estimation of the degree of randomness are considered. A strict definition of quasi-deterministic chaos is given. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 49–58, November, 2006.     

Including inputs and control within equation-free architectures for complex systems

The increasing ubiquity of complex systems that require control is a challenge for existing methodologies in characterization and controller design when the system is high-dimensional, nonlinear, and without physics-based governing equations. We review standard model reduction techniques such as Proper Orthogonal Decomposition (POD) with Galerkin projection and Balanced POD (BPOD). Further, we discuss the link between these equation-based methods and recently developed equation-free methods such as the Dynamic Mode Decomposition and Koopman operator theory. These data-driven methods can mitigate the challenge of not having a well-characterized set of governing equations. We illustrate that this equation-free approach that is being applied to measurement data from complex systems can be extended to include inputs and control. Three specific research examples are presented that extend current equation-free architectures toward the characterization and control of complex systems. These examples motivate a potentially revolutionary shift in the characterization of complex systems and subsequent design of objective-based controllers for data-driven models.