Complexity analyses of multi-wing chaotic systems

The complexities of multi-wing chaotic systems based on the modified Chen system and a multi-segment quadratic function are investigated by employing the statistical complexity measure （SCM） and the spectral entropy （SE） algorithm. How to choose the parameters of the SCM and SE algorithms is discussed. The results show that the complexity of the multi-wing chaotic system does not increase as the number of wings increases, and it is consistent with the results of the Grassberger-Procaccia （GP） algorithm and the largest Lyapunov exponent （LLE） of the multi-wing chaotic system.

Multi-Parameter Analysis of Optimal Transitions from Chaotic to Stable Regions for Two Classes of Systems

The study of the parameter space of chaotic systems is complicated by its high dimensionality (multi-parametricability). Two approaches to the study of chaotic systems are presented: multi-parameter analysis and optimal suppression of chaotic dynamics. For non-autonomous chaotic systems, this is the way to compare the effectiveness of various correction parameters that provide optimal removal of irregular dynamics. For the class of autonomous chaotic systems, this is the way to investigate the optimal conditions of super-stable behavior for the chaotic system.

Novel four-wing and eight-wing attractors using coupled chaotic Lorenz systems

This paper presents the problem of generating four-wing （eight-wing） chaotic attractors. The adopted method consists in suitably coupling two （three） identical Lorenz systems. In analogy with the original Lorenz system, where the two wings of the butterfly attractor are located around the two equilibria with the unstable pair of complex-conjugate eigenvalues, this paper shows that the four wings （eight wings） of these novel attractors axe located around the four （eight） equilibria with two （three） pairs of unstable complex-conjugate eigenvalues.

Implementation of a novel two-attractor grid multi-scroll chaotic system

This paper proposed a method of generating two attractors in a novel grid multi-scroll chaotic system. Based on a newly generated three-dimensional system, a two-attractor grid multi-scroll attractor system can be generated by adding two triangular waves and a sign function. Some basic dynamical properties, such as equilibrium points, bifurcations, and phase diagrams, were studied. Furthermore, the system was experimentally confirmed by an electronic circuit. The circuit simulation results and numerical simulation results verified the feasibility of this method.

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.

Fixed-Time Adaptive Time-Varying Matrix Projective Synchronization of Time-Delayed Chaotic Systems with Different Dimensions

This paper deals with the fixed-time adaptive time-varying matrix projective synchronization(ATVMPS)of different dimensional chaotic systems(DDCSs)with time delays and unknown parameters.Firstly,to estimate the unknown parameters,adaptive parameter updated laws are designed.Secondly,to realize the fixed-time ATVMPS of the time-delayed DDCSs,an adaptive delay-unrelated controller is designed,where time delays of chaotic systems are known or unknown.Thirdly,some simple fixed-time ATVMPS criteria are deduced,and the rigorous proof is provided by employing the inequality technique and Lyapunov theory.Furthermore,the settling time of fixed-time synchronization(Fix-TS)is obtained,which depends only on controller parameters and system parameters and is independent of the system’s initial states.Finally,simulation examples are presented to validate the theoretical analysis.

A new multi-scroll chaotic system

This paper proposes a new simple autonomous chaotic system which can generate multi-scroll chaotic attractors. The characteristic of this new multi-scroll chaotic system is that the 4n ＋ 2rn ＋ 4-scroll chaotic attractors are generated easily with n and m vaxying under n ≤ m. Various number of scroll chaotic attractors are illustrated not only by computer simulation but also by the realization of an electronic circuit experiment on EWB （Electronics Workbench）.

Generating one-,two-,three-and four-scroll attractors from a novel four-dimensional smooth autonomous chaotic system

A new four-dimensional quadratic smooth autonomous chaotic system is presented in this paper, which can exhibit periodic orbit and chaos under the conditions on the system parameters. Importantly, the system can generate one-, two-, three- and four-scroll chaotic attractors with appropriate choices of parameters. Interestingly, all the attractors are generated only by changing a single parameter. The dynamic analysis approach in the paper involves time series, phase portraits, Poincare maps, a bifurcation diagram, and Lyapunov exponents, to investigate some basic dynamical behaviours of the proposed four-dimensional system.

Novel four-dimensional autonomous chaotic system generating one-,two-,three- and four-wing attractors

In this paper, we propose a novel four-dimensional autonomous chaotic system. Of particular interest is that this novel system can generate one-, two, three- and four-wing chaotic attractors with the variation of a single parameter, and the multi-wing type of the chaotic attractors can be displayed in all directions. The system is simple with a large positive Lyapunov exponent and can exhibit some interesting and complicated dynamical behaviours. Basic dynamical properties of the four-dimensional chaotic system, such as equilibrium points, the Poincare map, the bifurcation diagram and the Lyapunov exponents are investigated by using either theoretical analysis or numerical method. Finally, a circuit is designed for the implementation of the multi-wing chaotic attractors. The electronic workbench observations axe in good agreement with the numerical simulation results.

A novel multi-scroll chaotic generator:Analysis, simulation, and implementation

Based on a new three-dimensional autonomous linear system and designing a specific form of saturated function series and a sign function with two variables of system, which are employed to increase saddle-focus equilibrium points with index 2, a novel multi-scroll chaotic system is proposed and its typical dynamical characteristics including bifurcation diagram, Poincare map, and the stability of equilibrium points are analyzed. The hardware circuit is designed and the experimental results are presented for confirmation.

Generalized Synchronization of Time-Delayed Discrete Systems

This paper establishes two theorems for two time-delayed （chaotic） discrete systems to achieve timedelayed generalized synchronization （TDGS）. These two theorems uncover the genera/forms of two TDGS systems via a prescribed transformation. As examples, we convert the Lorenz three-dimensional chaotic map to an equal time-delayed system as the driving system, and construct the TDGS driven systems according to the Theorems 1 and 2. Numerical simulations demonstrate the effectiveness of the proposed theorems.

Multi-Order Intermittent Chaotic Synchronization of Closed Phase Locked Loop

For the model of a Closed Phase Locked Loop (CPLL) communication System consists of both the transmission and receiver ends. This model is considered to be in a multi-order intermittent chaotic state. The chaotic signals are then synchronized along side with our system. This chaotic synchronization will be demonstrated and furthermore, a modulation will be formed to examine the system if it will perfectly reconstruct or not. Finally we will demonstrate the synchronization conditions of the system.

基于多混沌映射算法的图像可逆化加密仿真

原图像经过对矩阵元素随机打乱可得到加密图像,加密后的图像可以有效防止已知攻击。可逆映射可以高效地实现像素置乱,但由于离散混沌序列的初始条件较为敏感,因此像素扩散置乱难度较大。为此提出基于多混沌映射算法的图像可逆化加密方法,在图像加密过程中,采用扩散置乱和Arnold变换置乱图像,通过Logistic映射系统和Chen系统生成离散混沌序列,置乱后图像中红、绿、蓝三基色分别执行异或运算,从而输出加密图像。在图像解密过程中,分别对扩散置乱、Arnold变换以及图像加密执行逆映射,输出解密图像,完成图像可逆化加密。实验结果表明,所提方法密钥敏感性和原图与解密图像像素值分布更均匀、相邻像素相关性更低,鲁棒性更强。

基于小波压缩深度学习重构的多图像光学加密

为解决多图像加密算法密文体积大、加密效果差、重构效果不理想等问题,提出一种基于小波压缩和深度学习重构的多图像光学加密方法。利用小波压缩提取多图像的低频部分,将重排后的新图放入改进的FDT-DRPE光学加密系统中得到密文;利用矢量分解和螺旋相位变换克服FDT-DRPE不敏感问题;构造的L_S混沌系统提高密钥敏感性。提出新型深度学习网络模型BHCN,解决传统图像重构精度不高问题。实验结果表明,密文体积可压缩至原图的1/4,重构图像的峰值信噪比为34.57 dB,结构相似性为0.9521,与同类文献相比,速度更快,重构效果更好,安全性更高。

基于混沌多目标粒子群算法的综合能源调度

目的针对当前综合能源系统中资源协同优化效率不足、微网运行经济性和环保性差的问题,提出了一种计及风电储能及不稳定因素的微网优化调度方法。方法该方法在微网负荷侧需求响应对新能源消纳影响的基础上,以消纳新能源和削峰填谷为目的,提出了优化负荷曲线的方案;然后,考虑微网调度侧风电出力的不稳定性以及微网内部设备的耦合,进行优化调度以降低微网运行成本、减少环境惩罚费用并提高风电消纳平稳性;最后,采用混沌多目标粒子群算法对优化问题进行求解,并在风电不稳定度占比0%、5%、10%和15%时进行了算例仿真分析。结果当风电不稳定度为10%和加入风电储能,系统运行成本和环境治理费用最少,比方案1和无风电储能少6919.4元,风电平稳量也提高38 kWh。在电热冷网中,负荷侧加入需求响应后,系统得到稳定运行和能源合理利用,可以很好地满足负荷侧用能需求。从算法对比中,混沌多目标粒子群算法加入自适应权重和变异率后,具有较强的全局搜索能力和更好的准确性。结论该方法通过合理设置风电不稳定度能够有效降低运行成本和环境惩罚费用,提高风电稳定性,其次,负荷侧的需求响应可以一定程度地削峰填谷和消纳新能源。

一种多策略改进鲸鱼优化算法的混沌系统参数辨识

针对混沌系统参数辨识精度不高的问题,以鲸鱼优化算法(whale optimization algorithm,WOA)为基础,提出一种多策略改进鲸鱼优化算法(multi-strategy improved whale optimization algorithm,MIWOA)。采用Chebyshev混沌映射选取高质量初始种群,采用非线性收敛因子和自适应权重,提高算法收敛速度,为了避免算法陷入局部最优,动态选择自适应t分布或蚁狮优化算法更新后期位置,提高处理局部极值的能力。通过对10个基准函数和高维测试函数进行仿真试验,表明MIWOA具有良好的稳定性和收敛精度。将MIWOA应用于辨识Rossler和Lu混沌系统参数,仿真结果优于现有成果,表明本文MIWOA辨识混沌系统参数的高效性和实用性。

吸引子共存的四维多稳态混沌系统及同步电路

文中设计了一种具有多翼吸引子的四维混沌系统,通过改变系统的多组参数,观察到吸引子结构由四翼变为双翼。采用相图、Lyapunov指数谱、分岔图和复杂度等方法,验证系统的动力学特性。结果表明,通过改变系统参数和选择不同的初始值,系统呈现出极性相反但结构相似的吸引子共存现象。使用Multisim仿真软件进行了电路仿真,发现数值分析和模拟仿真结果一致,验证了系统的可实现性。最后,采用线性反馈同步法对该系统进行了同步控制,并成功实现了同步电路仿真。所设计系统具有丰富的多稳态特性,主从系统在极短的时间内达到了同步,同步效果良好,可广泛应用于保密通信领域。

一种分数阶混沌系统的通用增强型FPGA实现

针对目前分数阶混沌系统的FPGA设计实现通用程度不高的问题,文中给出了一种通用增强型FPGA算法。首先给出基于G-L定义的分数阶微分算法原理,再将一个已知的三维整数阶混沌系统扩展至分数阶多涡卷混沌系统,通过平衡点、分岔图及最大李氏指数谱分析了其动力学特性,最后运用可变长度移位寄存器,设计分数阶微分的通用增强型FPGA算法,并将其应用至分数阶多涡卷混沌系统。实验结果与数值仿真结果一致,该算法当修改参数时,无需设计新的代码,并能够动态调节记忆长度,且对步长没有严格限制。

基于多混沌系统的多图像加密算法

针对多幅图像在传输中的安全性问题,本文提出了一种基于多混沌系统的多图像加密算法.首先,利用离散小波变换对多幅图像进行预处理,得到一幅拼接的大图像;接着,利用logistic-sine-cosine (LSC)映射生成混沌序列,进而生成用于置乱的矩阵O对像素位置进行置乱;最后,采用超混沌Lorenz系统生成四维混沌序列,利用其对置乱后的图像进行双向扩散和行列置乱,获得最终密文图像.所提算法加解密过程简单,执行效率高.实验结果经多方面分析后得出该算法的密钥空间大,可以抵御多种攻击手段,具有较好的加密效果和安全性.

顾及纹理特征差异性的遥感影像数据分区域多密级加密方法

针对高分辨率遥感影像在网络传输、数据分享及应用过程中的安全性问题,本文从高分辨率遥感影像自身特点出发,提出了一种顾及纹理复杂度的遥感影像分区域多密级加密算法。首先,对大数据量的遥感影像进行分块处理,并将每个子图像块按照纹理特征的复杂度划分为简单、中等和复杂类型;然后,针对不同类型的子图像块采用不同维度的混沌系统分别加密得到密文块;最后,将密文块进行关联拼接,得到整体加密后的密文图像。通过采用真实遥感影像的试验分析结果表明,本文方法能够很好地实现遥感影像的信息隐藏,并且可以兼顾加密的安全性和时间复杂度,在大数据时代面向大众化应用的高分辨率遥感影像数据共享和图像处理领域具有潜在应用价值。