电场作用对改进的HR神经元模型的同步影响

MSF,即主稳定函数,是一种使用Lyapunov指数理论来确定复杂同型网络同步状态的稳定性的工具.负的MSF值表明网络可以同步.我们构建了一种双变量HR模型来描述神经元在电场作用下的同步行为,将神经元尺寸和外加电场作为影响电场作用的调控因素,利用简化的MSF方法,研究主稳定函数MSF和电荷尺寸及外加电场的关系.结果显示,电场效应对神经网络同步的作用是丰富的.施加较强的恒定电场可以促进网络同步,而施加交变电场则会抑制同步.另外,神经元半径也会影响电场效应的作用结果,在较大的神经元半径下,神经网络会更容易同步.     

分数阶超混沌系统的线性广义同步观测器设计

首先利用分数阶的常微分动力系统的稳定性理论,通过判断线性化后平衡点的稳定不变特性、辅助以分岔图分析等数值手段,给出了新近提出的改进型超混沌L讧系统对应分数阶系统产生混沌现象的阶次参数范围;进一步,设计了一类广义线性同步观测器,该观测器的动力学行为能与原系统实现任意的线性关系的广义同步,而经典的完全同步、反相同步以及投影同步可以视为本文提出方法的特例．最后的数值仿真进一步证实了本文提出的观测器设计方案的有效性．     

非线性耦合统一混沌系统的同步

研究非线性耦合的两个统一混沌系统的同步问题．首先利用线性时变系统的稳定性理论,推出当两个统一混沌系统的误差系统渐近稳定时,耦合函数的参数选择范围,从而得出两个统一混沌系统全局渐近同步的充分条件．然后基于Routh-Hurwitz稳定性判别方法,同样得出了混沌系统同步的一个充分条件．通过数值仿真发现,根据第1种方法选择的参数能使混沌系统全局渐近同步;而依据第2种方法选择的参数,即使误差系统系数矩阵的瞬间特征值具有负实部,也会出现混沌同步失去的情况,从而表明了该分析方法的有效性．     

Exponential Synchronization of Stochastic Fuzzy Cellular Neural Networks with Reaction-Diffusion Terms via Periodically Intermittent Control

This paper considers the exponential synchronization of stochastic fuzzy cellular neural networks with time-varying delays and reaction-diffusion terms based on p-norm. Motivated by the achievements from both the stability of fuzzy cellular neural networks with stochastic perturbation and reaction-diffusion effects and the synchronization issue of coupled chaotic delayed neural networks by using periodically intermittent control approach, a periodically intermittent controller is proposed to guarantee the exponential synchronization of the coupled chaotic neural networks by using Lyapunov stability theory and stochastic analysis approaches. The synchronization results presented in this paper generalize and improve many known results. This paper also presents an illustrative example and uses simulated results of this example to show the feasibility and effectiveness of the proposed scheme.     

欺骗攻击环境下具有执行器故障的跳变耦合 信息物理系统的同步控制

针对一类离散Markov跳变耦合信息物理系统(CPS)的同步控制问题,在考虑系统参数跳变、耦合参数跳变、控制信息不完全和人为攻击的情况下,设计同步控制器实现CPS的同步.首先,给出具有随机欺骗攻击和执行器故障的Markov跳变耦合CPS模型.其次,基于矩阵Kronecker积,得到同步误差系统,将CPS的同步控制问题转化为同步误差系统的稳定性分析问题.再次,通过构造合适的Lyapunov-Krasovskii泛函,并利用Lyapunov稳定性理论和线性矩阵不等式方法得到使同步误差系统稳定的充分条件,在此基础上,设计同步控制器实现对Markov跳变耦合CPS的同步控制.最后,通过数值仿真例子说明该同步控制器设计方法的有效性.     

混沌同步及其在信息通讯中的应用

利用混沌信号作为载体实现信息通讯,其关键问题是发射机系统与接收机系统的混沌同步。本文应用MATLAB（数值计算实验）对由两个三维混沌系统（Chua系统与Lorenz系统）构造的高维超混沌系统进行了动态模拟,实现了高维系统的混沌同步及其信息通讯的编码与解码过程。模拟结果表明,高维系统的同步可以通过各子系统的混沌同步逐级实现,而初级子系统的同步程度、抗干扰性以及稳定性决定了高维系统的同步能力,模拟过程可以对此进行有效的数值分析,为应用研究的技术实现提供了依据。     

New direct lyapunov-type method for studying synchronization problems

A new approach of the Lyapunov type is presented for the stability analysis of a class of time invariant, nonlinear dynamical systems, which are characterized by a periodic nonlinearity, and the existence of an infinite number of stationary states. In particular, the method can be applied for studying transient stability problems in power systems, and the synchronization of phase lock circuits. Frequency criteria are developed for the convergence of all solutions to an equilibrium state, and a procedure, based on these criteria, is outlined for constructing stability regions for a collection of neighboring equilibria. When applied to power—or phase lock systems, these regions can be interpreted as synchronization regions within an arbitrary, given number of cycles. Also, some new results are obtained with respect to synchronization conditions within the first cycle.     

可变帧结构的PCM遥测帧同步器设计

针对传统帧同步器只能对固定帧格式的数据进行帧同步的缺点,提出一种基于现场可编程门阵列(FPGA)的帧同步方案,用户可根据实际需求通过上位机软件配置帧长、帧同步字等参数,实现对不同帧结构的PCM遥测数据进行帧同步。该方案采用了参数可调的同步容错及前后方保护机制,提高了帧同步的可靠性和稳定性。给出了帧同步方案的工作原理,以及关键技术的实现方法,在实际应用中对其同步性能进行分析,测试结果表明该方案对不同帧结构的数据均可实现帧同步。     

分数阶混沌系统的延迟同步

基于分数阶线性系统的稳定性理论，结合反馈控制和主动控制方法，提出了实现分数阶混沌系统的延迟同步的一种新方法．该方案通过设计合适的控制器将分数阶混沌系统的延迟同步问题转化为分数阶线性误差系统在原点的渐近稳定性问题．分数阶Chen系统的数值模拟结果验证了该方案的有效性．     

不确定Lorenz系统的参数识别与异结构同步

设计了一种参数识别器和同步控制器,研究了不确定混沌系统的参数识别与异结构同步问题．根据稳定性原理,确定了参数识别器和同步控制器的结构,以不确定Lorenz混沌系统和Rossler混沌系统为例,验证了其有效性．仿真模拟结果表明,在参数识别器和同步控制器的共同作用下,异结构不确定Lorenz混沌系统和Rossler混沌系统可以达到完全同步,并且不确定Lorenz混沌系统的参数全部可以得到识别．     

统一混沌系统的混沌观测器同步控制及其应用

根据连续时间混沌系统可由单变量及其导数重构相空间的原理,采用混沌观测器同步方法.研究了统一混沌系统的同步控制问题.基于连续系统的稳定性准则,提出了统一混沌系统的混沌观测器同步定理.将该同步方法应用于保密通信,设计了基于时分复用的混沌掩盖保密通信新方案,并对该方案的保密性能进行了分析.基于MATLAB的数值仿真结果证明了同步控制方法和保密通信方案的有效性.     

非光滑系统的混沌同步

通过广义哈密顿系统和观测器法，本文将非光滑混沌系统的同步问题转化成了研究光滑系统零解的稳定性，从而给出了混沌同步的条件．对具体的带于摩擦，碰撞的Duffing振子分别进行研究，使其达到了完全同步，表明该方法的正确性．     

Exponential Synchronization of Memristive Chaotic Recurrent Neural Networks Via Alternate Output Feedback Control

This paper considers the global exponential synchronization problem of two memristive chaotic recurrent neural networks with time‐varying delays using periodically alternate output feedback control. First, the periodically alternate output feedback control rule is designed for the global exponential synchronization of two memristive chaotic recurrent neural networks. Then, according to the Lyapunov stability theory, we construct an appropriate Lyapunov‐Krasovskii functional to derive several new sufficient conditions guaranteeing exponential synchronization of two memristive chaotic recurrent neural networks under periodically alternate output feedback control. Compared with existing results on synchronization conditions on the basis of linear matrix inequalities of memristive chaotic recurrent neural networks, the derived results complement, extend earlier related results, and are also easy to validate in this paper. An illustrative example is provided to illustrate the effectiveness of the synchronization criteria.     

同步精度稳定的多跳无线传感器网络时间同步算法

对无线传感器网络时间同步精度稳定性进行了研究，给出了OTSP算法中影响多跳同步精度的因素，在此基础上提出了一种新的同步精度稳定的算法。该算法估算出了不同节点间的晶振频率偏差，并使得多跳网络中的每个节点都能精确地同步到时间基准节点。实验结果证明该算法在同步精度的稳定性方面优于OTSP算法。     

A boundary control for motion synchronization of a two-manipulator system with a flexible beam

A novel synchronization motion control method is proposed in this paper for the system in which two manipulators are constrained by a flexible beam. Different from the general synchronization control method, the coupling dynamics among various actuators is considered as the shear force, which results from the synchronization errors. Then a simple boundary control is introduced to realize the synchronization motion of actuators by suppressing the shear force. In order to avoid the drawbacks of assumed modes model, the dynamic model of flexible beam is described by a distributed parameter model in this paper. A Riesz basis method is used to prove that the proposed control law can guarantee the synchronization system to be exponential stability. Simulation results demonstrate that the proposed method can effectively improve the performance of synchronization motion compared with other methods.     

基于分数阶积分器的分数阶混沌系统状态观测器同步研究

提出了一种基于分数阶积分器的分数阶混沌系统状态观测器同步算法。通过引入一个新的变量,该变量是将驱动系统的输出信号与传输信道中干扰的和进行分数阶积分处理,然后再作为输入信号加到观测系统中,以便实现分数阶混沌系统的状态观测系统同步。然后利用Lyapunov稳定性理论和线性矩阵不等式证明了该方法的正确性。将该同步方法应用于分数阶Chen混沌系统,得出了同步误差曲线,仿真结果表明了该同步方法的有效性,最终实现了分数阶混沌系统的状态观测器同步。     

改进环路结构的Gardner定时恢复算法

针对经典的Gardner定时恢复算法存在同步建立时间长、同步稳定性能差等问题，提出一种改进环路结构的Gardner定时同步恢复算法。首先，该算法选用立方插值和分段抛物线插值两种插值滤波器进行插值，得到两路最佳插值序列；其次，分别计算两路插值序列对应的定时误差并求加权平均值，得到环路的定时误差；最后，以两路最佳插值序列的加权平均值作为环路输出。针对正交相移键控（QPSK）、正交幅度调制（16QAM）两种调制信号进行了仿真验证。仿真结果表明，该改进算法作用于QPSK信号时同步稳定性更好，相比作用于16QAM信号，其环路开始同步时码元的位置对应的序列数明显减小；并且该算法在信噪比为-5 dB的情况下使QPSK信号星座图收敛半径为0.26左右，与类似锁频锁相（FPLL）的改进Gardner定时恢复算法相比收敛半径减小约0.08，该算法有效地缩短了同步建立的时间，提高了环路的稳定性，可广泛应用于高速解调系统。     

一个新混沌系统的参数不确定自适应同步

针对一个新的混沌系统,简单分析了其稳定性,并对其进行同步控制.在研究单变量驱动同步的基础上,应用自适应控制理论,研究了当系统参数不确定时的同步问题.根据Lyapunov稳定性理论,推导了当参数不确定时误差系统渐近稳定的充分条件,构造了合适的自适应控制规律快速辨识了系统参数.数值仿真结果表明方法是有效的和可行的,且自适应控制规律的设计简单可靠,并实现了两个混沌系统的状态同步.同时该方法可推广到情况类似的其他混沌系统.     

Anti‐Synchronization and Intermittent Anti‐Synchronization of Two Identical Delay Hyperchaotic Chua Systems Via Linear Control

This work is concerned with anti‐synchronization and intermittent anti‐synchronization of two identical delay hyperchaotic Chua systems with linear control approaches. In the first two schemes, based on Lyapunov stability theory, some sufficient conditions for achieving anti‐synchronization of two identical delay hyperchaotic Chua systems are derived, numerical simulation results are presented to demonstrate the effectiveness of the proposed anti‐synchronization schemes. In the third scheme, the anti‐synchronization conditions are obtained by numerical method. In the fourth scheme, only one state of the response system is controlled via linear control, we report an interesting phenomenon of intermittent anti‐synchronization.     

Some new criteria for lag synchronization of chaotic Lur＇e systems by replacing variables control

Some new criteria for the chaotic lag synchromzation are proposed. At first, lag synchronization scheme for identical master-slave Lur‘e systems by replacing variables control and the relevant error system are given, and the relations between absolute stability of the error system and the chaotic lag synchromzation are described. Then. based on a quadratic Lyapunov function, two new Lur‘e criteria for the above chaotic lag synchronization are proved. Four corresponding frequency domain criteria are further derived by means of Meyer-Kalman-Yacubovia Lemma. These frequency domain criteria are apphed to analyze the lag synchromzation of general master-slave Chua‘s circuits so that some ranges of the parameters in which the master-slave Chua‘s circuits achieve chaotic lag synchronization by replacing single-variable control are attained. Finally, some examples are given to verify the theoretical results.