基于广义混沌映射切换的混沌同步保密通信

提出了一种基于广义混沌映射切换的混沌同步保密通信方式.这种通信方式首先构建产生多种混沌序列的广义混沌映射模型,然后在不同时段根据切换策略产生不同混沌序列,在发送端,将信号与混沌载波之和取模运算后再嵌入混沌映射的输入端进行迭代运算以实现调制;在接收端,根据切换协议,用同一个相应的广义混沌映射模型从接收信号中提取混沌载波并进而恢复信息信号.研究结果表明:这种基于广义混沌映射切换的混沌同步通信方式比基于单一混沌系统的保密通信方式具有更强的抗干扰能力,保密性能更好,且实现简单. 关键词： 混沌 混沌映射切换 同步 保密通信     

耦合不连续系统同步转换过程中的多吸引子共存

本文研究了耦合不连续系统的同步转换过程中的动力学行为, 发现由混沌非同步到混沌同步的转换过程中特殊的多吸引子共存现象. 通过计算耦合不连续系统的同步序参量和最大李雅普诺夫指数随耦合强度的变化, 发现了较复杂的同步转换过程: 临界耦合强度之后出现周期非同步态(周期性窗口); 分析了系统周期态的迭代轨道,发现其具有两类不同的迭代轨道: 对称周期轨道和非对称周期轨道, 这两类周期吸引子和同步吸引子同时存在, 系统表现出对初值敏感的多吸引子共存现象. 分析表明, 耦合不连续系统中的周期轨道是由于局部动力学的不连续特性和耦合动力学相互作用的结果. 最后, 对耦合不连续系统的同步转换过程进行了详细的分析, 结果表明其同步呈现出较复杂的转换过程.     

基于改进克隆选择算法的统一混沌系统同步控制与参数辨识

提出一种改进的克隆选择算法用于解决混沌系统的参数辨识问题.该算法利用抗体的高频变异和受体编辑两种机制有效平衡算法的全局探索与局部开发，并引入向精英抗体学习策略进一步提高算法的收敛质量.对10个优化问题的实验表明：所提出算法在求解精度、收敛速度以及稳定性方面具有更好的性能.以参数未知统一混沌系统的同步控制为研究对象，合理设计同步控制器，并对同步系统的稳定性进行理论分析.通过对同步比例因子的设置，实现统一混沌系统的完全同步、反同步、投影同步等多种同步方式.仿真实验结果表明该方法能够实现对未知系统参数的精确辨识以及驱动-响应系统的有效同步控制，验证了所提方法的可行性与有效性.     

基于量子粒子群算法的混沌系统同步控制及参数辨识

针对异结构且参数未知混沌系统的同步控制,设计同步控制器并对误差系统的稳定性进行理论分析.通过合理选择优化目标函数,利用量子粒子群算法高效的全局寻优能力,实现混沌系统的未知参数辨识,有效降低同步控制器的开发难度.以Rössler混沌系统与Lorenz混沌系统的异结构同步为研究对象,进行数值仿真实验,结果表明该方法能够实现驱动-响应系统的快速混沌同步及系统未知参数的准确辨识,并验证该方法的可行性和有效性.     

基于单向注入垂直腔面发射激光器系统的密钥分发

随机源对于信息理论安全的密钥分发至关重要,本文提出了一种基于单向注入垂直腔面发射激光器系统的密钥分发方案.首先基于单向注入的方式产生无时延特征的激光混沌信号,并通过单向注入驱动两个从激光器产生带宽增强的混沌同步信号.然后经过采样、量化以及异或等后处理,生成密钥流.数值仿真结果表明,在单阈值情况下,合法用户之间的误比特率低至1%左右,合法用户与窃听者之间的误比特率都高于10%;在双阈值情况下,误比特率可以低至10^-6.最后,对生成的密钥流进行了NIST随机性测试.该方案有效地增强了密钥分发的安全性.     

Secure communication through synchronization of two chaotic systems with continuous feedback method

Secure communication through synchronization of chaotic signals is experimentally demonstrated using a nonlinear hybrid optical system. We use a small-time continuous feedback method to achieve synchronization. This method does not require that the system under study be divided into subsystems.     

Controlling and synchronizing spatiotemporal chaos of the coupled Bragg acousto-optical bistable map system using nonlinear feedback

In this paper we present the control and synchronization of a coupled Bragg acousto-optic bistable map system using nonlinear feedback technology. This nonlinear feedback technology is useful to control a temporally chaotic system as well as a spatiotemporally chaotic system. It can be extended to synchronize the spatiotemporal chaos. It can work in a wide range of the controlled and synchronized signals, so it can decrease the sensitivity down to a noise level. The synchronization can be obtained by the analysis of the largest conditional Lyapunov exponent spectrum, and easily implemented in practical systems just by adjusting the coupled strength without any pre-knowledge of the dynamic system required.     

Synchronization and parameter identification of one class of realistic chaotic circuit

In this paper, the synchronization and the parameter identification of the chaotic Pikovsky--Rabinovich (PR) circuits are investigated. The linear error of the second corresponding variables is used to change the driven chaotic PR circuit, and the complete synchronization of the two identical chaotic PR circuits is realized with feedback intensity k increasing to a certain threshold. The Lyapunov exponents of the chaotic PR circuits are calculated by using different feedback intensities and our results are confirmed. The case where the two chaotic PR circuits are not identical is also investigated. A general positive Lyapunov function V, which consists of all the errors of the corresponding variables and parameters and changeable gain coefficient, is constructed by using the Lyapunov stability theory to study the parameter identification and complete synchronization of two non-identical chaotic circuits. The controllers and the parameter observers could be obtained analytically only by simplifying the criterion dV/dt<0 (differential coefficient of Lyapunov function V with respect to time is negative). It is confirmed that the two non-identical chaotic PR circuits could still reach complete synchronization and all the unknown parameters in the drive system are estimated exactly within a short transient period.     

Adaptive generalized synchronization between Chen system and a multi-scroll chaotic system

Based on Lyapunov theory, the adaptive generalized synchronization between Chen system and a multi-scroll chaotic system is investigated. According to the form of target function a proper adaptive controller is designed, by which the controlled Chen system can be synchronized with a multi-scroll chaotic system including unknown parameters. The Lyapunov direct method is exploited to prove that the synchronization error and parameter identification error both converge to zero. Numerical simulation results verify the feasibility of the proposed method further.     

利用周期信号驱动Chua电路实现相同步

我们在实验上和理论上对周期信号驱动的混沌电路的相同步问题进行了研究。我们选择三类周期信号作为驱动信号，包括Chua电路产生的周期信号，正弦信号和脉冲信号。改变驱动信号的频率、振幅和脉冲信号的占空比，在周期信号和混沌信号存在小的频率失配的条件下，驱动信号的振幅在适当的变化范围内，以及脉冲信号的占空比在适当的变化范围内，都可以获得相同步。甚至当占空比小到3%的情况下，仍然可以得到相同步。特别是这类脉冲信号的控制在实际中是有意义的。     

混沌系统自适应追踪控制新方法

提出一种混沌系统自适应追踪控制任意参考信号的新方法.该方法是通过预先设计出补偿控制器将混沌系统状态变量对参考信号的追踪控制问题转化为同结构混沌系统状态变量的自适应同步问题,再通过设计出自适应控制器,使同结构混沌系统全局渐近达到同步,追踪控制器为补偿控制器和自适应控制器的代数和.基于Lyapunov稳定性原理,理论上严格证明了利用本方法所设计追踪控制器的正确性.最后,以超混沌Chen系统为控制对象,利用本方法设计出追踪控制器完成了对不动点,正、余弦信号,同结构混沌系统状态变量,异结构混沌系统状态变量的追踪控 关键词： 自适应追踪控制 补偿控制器 自适应控制器 追踪控制器     

Generalized projective synchronization of a class of chaotic (hyperchaotic) systems with uncertain parameters

In this paper is investigated the generalized projective synchronization of a class of chaotic (or hyperchaotic) systems, in which certain parameters can be separated from uncertain parameters. Based on the adaptive technique, the globally generalized projective synchronization of two identical chaotic (hyperchaotic) systems is achieved by designing a novel nonlinear controller. Furthermore, the parameter identification is realized simultaneously. A sufficient condition for the globally projective synchronization is obtained. Finally, by taking the hyperchaotic Lü system as example, some numerical simulations are provided to demonstrate the effectiveness and feasibility of the proposed technique.     

基于自适应模糊控制的分数阶混沌系统同步

本文主要研究了带有未知外界扰动的分数阶混沌系统的同步问题.基于分数阶Lyapunov稳定性理论,构造了分数阶的参数自适应规则以及模糊自适应同步控制器.在稳定性分析中主要使用了平方Lyapunov函数.该控制方法可以实现两分数阶混沌系统的同步,使得同步误差渐近趋于0.最后,数值仿真结果验证了本文方法的有效性.     

Complete switched modified function projective synchronization of a five-term chaotic system with uncertain parameters and disturbances

A five-term three-dimensional (3D) autonomous chaotic system with an exponential nonlinear term is reported in this paper. Basic dynamical behaviours of the chaotic system are further investigated. Then a new synchronization phenomenon, complete switched modified function projective synchronization (CSMFPS), for this novel five-term chaotic system with uncertain parameters and disturbances is investigated. This paper extends previous work, where CSMFPS of chaotic systems means that all the state variables of the drive system synchronize with different state variables of the response system. As the synchronization scheme has many combined forms, it is a promising type of synchronization and can provide greater security in secure communication. Based on Lyapunov stability theory, a robust adaptive controller is contrived to acquire CSMFPS, parameter identification and suppress disturbances simultaneously. Finally, the Lorenz system and the new five-term chaotic system are taken as examples and the corresponding numerical simulations are presented to verify the effectiveness and feasibility of the proposed control scheme.     

适合传输快变信息信号的混沌调制保密通信

提出一种新的混沌调制通信方法.利用一个自适应控制器跟踪信息信号的误差对产生混沌载波的发射系统进行参数调制.同时，信息信号直接与混沌载波相乘作为发射信号驱动接收系统.在接收端，另一个自适应控制器维持收发系统的混沌同步并恢复出信息信号.由于同步误差与信息信号无关，从而实现了大幅度、快时变信息信号的混沌调制通信.理论分析和数值模拟的结果表明该方法增强了低维混沌系统的通信保密性. 关键词： 混沌调制 保密通信 自适应控制器 蔡氏电路     

异结构不确定混沌系统的同步控制与参数识别

设计了一种同步控制器和参数识别器来实现异结构不确定混沌系统的同步控制。以单模激光Lorenz系统和不确定Genesio系统为例,验证了这种控制器的有效性。根据Lyapunov稳定性理论,分步构造出Lyapunov函数,从而给出同步控制器和参数识别器的结构。仿真结果表明：利用本文提出的同步控制方案,仅用一个控制器就能使不确定Genesio系统的所有状态变量严格地跟踪Lorenz系统的混沌轨迹,而且误差变量经过短暂的时间序列以后始终平稳地趋于零,实现了异结构混沌系统的混沌同步,且不确定Genesio系统的参数全部可以得到识别。     

Synchronization of reconstructed dynamical systems

The problem of constructing synchronizing systems to observed signals is approached from a data driven perspective, in which it is assumed that neither the drive nor the response systems are known explicitly but have to be derived from the observations. The response systems are modeled by utilizing standard methods of nonlinear time series analysis applied to sections of the driving signals. As a result, synchronization is more robust than what might be expected, given that the reconstructed systems are only approximations of the unknown true systems. Successful synchronization also may be accomplished in cases where the driving signals result from nonlinearly transformed chaotic states. The method is readily extended and applied to limited real-time predictions of chaotic signals.     

时空混沌系统参量辨识律的设计与投影同步研究

研究了相互耦合的时空混沌系统的参量辨识与投影同步问题. 依据Lyapunov定理, 设计了参量辨识律和表征耦合强度的待定函数的自适应律, 对响应系统中的未知参量进行了有效辨识, 并完成了时空混沌系统的投影同步研究. 采用具有时空混沌行为的Burgers方程作为实例进行了仿真分析.     

基于1550 nm垂直腔面发射激光器的长距离双向双信道光纤混沌保密通信研究

基于同一混沌信号光注入下两个1550 nm垂直腔面发射激光器 (VCSELs) 中两对应线性偏振模式之间的混沌同步, 提出了一种可实现信息的长距离双向双信道光纤混沌保密通信的系统模型, 并对该系统的同步、双向双信道通信以及光纤信道对信息传输的影响等性能进行了相关仿真研究. 结果表明: 在由驱动混沌激光器所产生的同一混沌光注入下, 两响应激光器中对应的两线偏振模式之间均可实现高质量的等时混沌同步, 且驱动激光器与两响应激光器间的同步系数较低; 基于两响应激光器之间对应线偏振模式的高质量混沌同步, 可实现双向双信道混沌通信; 采用单模保偏光纤 (或色散位移保偏光纤) 作为通信信道, 2.5 Gbit/s信息在传输60 km (或200 km) 后解调信息的Q因子能保持在6以上. 关键词： 垂直腔面发射激光器 (VCSELs) 双向双信道 混沌通信 光纤     

Generalized reduced-order synchronization of chaotic system based on fast slide mode

A new kind of generalized reduced-order synchronization of different chaotic systems is proposed in this paper. It is shown that dynamical evolution of third-order oscillator can be synchronized with the canonical projection of a fourth-order chaotic system generated through nonsingular states transformation from a cell neural net chaotic system. In this sense, it is said that generalized synchronization is achieved in reduced-order. The synchronization discussed here expands the scope of reduced-order synchronization studied in relevant literatures. In this way, we can achieve generalized reduced-order synchronization between many famous chaotic systems such as the second-order D\"{u}ffing system and the third-order Lorenz system by designing a fast slide mode controller. Simulation results are provided to verify the operation of the designed synchronization.