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Int. J. Bifurc. Chaos最新文献

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Approximate Equivalence of Higher-Order Feedback and Its Application in Chaotic Systems 高阶反馈的近似等效性及其在混沌系统中的应用
Pub Date : 2024-01-01 DOI: 10.1142/s021812742450007x
Yikai Gao, Chunbiao Li, Irene Moroz, Haiyan Fu, Tengfei Lei
Based on the feature of piecewise linear (PWL) functions, a nonlinear feedback of a higher-order system can be transformed to an approximately equivalent PWL function so as to ease system implementation in engineering. As an example, a cubic feedback term can be approximately equivalently transformed to be a PWL function. Since the PWL function can be expressed by many simple functions such as signum function and absolute-valued function, the cubic term can be approximately equivalently replaced with these functions. Consequently, the method of approximate equivalence is employed in the JCS-08-13-2022 (JCS) chaotic system for simple circuit design and implementation. In this approach, the widely used multipliers are avoided and the circuits become more economical and also more robust. In this paper, the cubic Chua’s resistor is equivalently approximately replaced by a PWL function. To show the effectiveness of the approximate equivalence, numerical simulations are demonstrated and verified by circuit implementation.
根据分片线性(PWL)函数的特点,可以将高阶系统的非线性反馈转化为近似等效的 PWL 函数,从而简化工程中的系统实施。例如,立方反馈项可以近似等效地转换为 PWL 函数。由于 PWL 函数可以用许多简单的函数来表示,如符号函数和绝对值函数,因此立方项可以近似等价地替换为这些函数。因此,JCS-08-13-2022(JCS)混沌系统中采用了近似等价的方法来进行简单的电路设计和实现。在这种方法中,避免了广泛使用的乘法器,电路变得更经济、更稳健。在本文中,立方蔡氏电阻被 PWL 函数近似等效替代。为了证明近似等效的有效性,本文进行了数值模拟演示,并通过电路实现进行了验证。
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引用次数: 0
Global Dynamics of a Fisheries Economic Model with Gradient Adjustment 具有梯度调整功能的渔业经济模型的全球动态变化
Pub Date : 2024-01-01 DOI: 10.1142/s0218127424500123
Huan Zhou, Xian-Feng Li, Jun Jiang, Andrew Y. T. Leung
Taking into account the nonlinear demand function, we have developed a multi-agent fishery economic model, where a multitude of agents are bounded by rationality. The fishing decisions of these agents are driven by a profit gradient mechanism. To assess the local stability of the system, stability analysis is performed with the Jury criterion. The investigation has revealed the presence of two conventional paths to chaos, namely, the flip bifurcation and the Neimark–Sacker bifurcation. This was achieved by mapping the stability regions and stability curves of the Nash equilibrium. The multistability of the system is further explored on two-dimensional planes on which the influence of joint parameters on the system’s stability is demonstrated. The existence of Arnold’s tongue has demonstrated unparalleled complexity and intricate interactions across different scales of the system. Both critical curves and basins of attraction are illustrated to gain insight into global bifurcations. The chaotic attractor is found to be confined within specific boundaries. The findings clearly show higher maximum instantaneous demand, relatively slower adjustment speed, and lower price sensitivity. Arguably, a controlled cost would lead to sustainable fishing resources. Moreover, the results also suggest that the agents would benefit more from confined conditions.
考虑到非线性需求函数,我们建立了一个多代理渔业经济模型,其中众多代理都受到理性的约束。这些代理的捕鱼决策由利润梯度机制驱动。为了评估系统的局部稳定性,我们使用 Jury 准则进行了稳定性分析。调查显示,存在两条通向混沌的常规路径,即翻转分岔和 Neimark-Sacker 分岔。这是通过绘制纳什均衡的稳定区域和稳定曲线实现的。在二维平面上进一步探讨了系统的多稳定性,在二维平面上证明了联合参数对系统稳定性的影响。阿诺德之舌的存在展示了系统不同尺度上无与伦比的复杂性和错综复杂的相互作用。临界曲线和吸引盆地都得到了说明,以深入了解全局分岔。研究发现,混沌吸引子被限制在特定的边界内。研究结果清楚地表明,最大瞬时需求较高,调整速度相对较慢,价格敏感性较低。可以说,控制成本将导致渔业资源的可持续发展。此外,研究结果还表明,受限条件下的行为主体将获益更多。
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引用次数: 0
Some Properties of a Discrete Lorenz System Obtained by Variable Midpoint Method and Its Application to Chaotic Signal Modulation 用可变中点法获得的离散洛伦兹系统的一些特性及其在混沌信号调制中的应用
Pub Date : 2024-01-01 DOI: 10.1142/s0218127424500093
V. Rybin, D. Butusov, Ivan Babkin, Dmitriy Pesterev, Viacheslav Arlyapov
Various discretization effects caused by applying numerical integration techniques to continuous chaotic systems are broadly studied in nonlinear science. Along with the negative impact on the precision of the various finite-difference schemes, such effects may have surprisingly fruitful practical applications, e.g. pseudo-random number generation, image encryption with improved diffusion and confusion properties, chaotic path planning, and many others. One such application is chaos-based communication systems which gained attention in recent decades due to their high covertness and broadband transmission capability. A crucial problem in the design of chaotic communication systems is the modulation of carrier signals. Due to the noise-like properties of chaotic signals, they can barely be modulated using the same methods as conventional harmonic signals. Thus, developing new modulation techniques is of great interest in the field of chaotic communications. In this study, we investigate the discrete model of the Lorenz oscillator obtained using controllable midpoint numerical integration and develop a novel modulation technique for chaos-based communication systems. We discover and analyze the multistability phenomenon in the dynamics of the investigated finite-difference Lorenz model through bifurcation, the basin of attraction, and Lyapunov spectrum analysis procedures. Using a specially designed testbench, we explicitly show that the proposed modulation method outperforms commonly used parametric modulation and is nearly equal to the state-of-the-art symmetry-based modulation in terms of covertness and noise resistivity. In addition, the proposed modulation technique is much easier to implement using computer arithmetics, especially in fixed-point hardware. The reported results may be efficiently applied to designing advanced chaos-based communications systems or improving the characteristics of existing communication system architectures.
非线性科学领域广泛研究了对连续混沌系统应用数值积分技术所产生的各种离散化效应。除了对各种有限差分方案的精度产生负面影响之外,这些效应还可能在实际应用中产生令人惊讶的丰硕成果,例如伪随机数生成、具有改进的扩散和混淆特性的图像加密、混沌路径规划等。近几十年来,基于混沌的通信系统因其高度隐蔽性和宽带传输能力而备受关注。混沌通信系统设计中的一个关键问题是载波信号的调制。由于混沌信号具有类似噪声的特性,因此几乎无法使用与传统谐波信号相同的方法对其进行调制。因此,开发新的调制技术在混沌通信领域具有重大意义。在本研究中,我们研究了利用可控中点数值积分获得的洛伦兹振荡器离散模型,并为基于混沌的通信系统开发了一种新型调制技术。我们通过分岔、吸引盆地和李亚普诺夫频谱分析程序,发现并分析了所研究的有限差分洛伦兹模型动力学中的多稳态现象。通过使用专门设计的测试平台,我们明确表明所提出的调制方法优于常用的参数调制方法,并且在遮蔽性和抗噪性方面几乎等同于最先进的基于对称性的调制方法。此外,所提出的调制技术更易于使用计算机算术实现,特别是在定点硬件中。所报告的结果可有效地应用于设计先进的基于混沌的通信系统或改善现有通信系统架构的特性。
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引用次数: 2
Generating Chaos with Saddle-Focus Homoclinic Orbit 用鞍焦同位轨道生成混沌
Pub Date : 2024-01-01 DOI: 10.1142/s0218127424500111
Chaoxia Zhang, Shangzhou Zhang, Yuqing Zhang
This paper develops an anticontrol approach to design a 3D continuous-time autonomous chaotic system with saddle-focus homoclinic orbit, based on two chaotification criterions for all orbits to be globally bounded with positive Lyapunov exponents. By using the Shil’nikov theorem, a Poincaré return map near the origin is found in the designed controlled system, confirming the existence of chaos in sense of the Smale horseshoe.
本文基于两个混沌化判据,即所有轨道均为全局有界且Lyapunov指数为正,提出了一种反控制方法,以设计具有鞍焦同轴轨道的三维连续时间自主混沌系统。利用Shil'nikov定理,在设计的受控系统中发现了原点附近的Poincaré回归图,证实了Smale马蹄铁意义上混沌的存在。
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引用次数: 0
Modeling the Bifurcation Dynamics of Rumor Propagation in the Spatial Environment 空间环境中谣言传播的分岔动态建模
Pub Date : 2024-01-01 DOI: 10.1142/s0218127424500056
Linhe Zhu, Xinlin Chen
The harm caused by rumors is immeasurable. Studying the dynamic characteristics of rumors can help control their spread. In this paper, we propose a nonsmooth rumor model with a nonlinear propagation rate. First, we utilize the positive invariant regions to prove the boundedness of solutions. Second, we analyze the conditions for the existence of equilibrium points in both the left and right systems. Additionally, we confirm the occurrence of saddle-node bifurcation in the left system. Next, by considering the influence of spatial diffusion, we establish the conditions for Turing instability. Then we discuss the conditions for spatial homogeneous and inhomogeneous Hopf bifurcations in the left and right systems, respectively. We differentiate between supercritical and subcritical bifurcations using the Lyapunov coefficient. Furthermore, we examine the conditions for the existence of discontinuous Hopf bifurcation at the demarcation point. Finally, in the numerical simulation section, we validate our theorems on Turing patterns. We also investigate the impact of parameter changes on rumor propagation and conclude that an increase in the psychological inhibitory factor significantly reduces the rate of rumor propagation, providing an effective strategy for curbing rumors. To that end, we fit actual data to our system and the results are excellent, confirming the validity of the system.
谣言造成的危害不可估量。研究谣言的动态特征有助于控制谣言的传播。本文提出了一个具有非线性传播率的非光滑谣言模型。首先,我们利用正不变区域来证明解的有界性。其次,我们分析了左右系统中平衡点存在的条件。此外,我们还证实了左系统中鞍节点分岔的发生。接下来,通过考虑空间扩散的影响,我们确定了图灵不稳定性的条件。然后,我们分别讨论了左系统和右系统出现空间均质和非均质霍普夫分岔的条件。我们用 Lyapunov 系数来区分超临界和亚临界分岔。此外,我们还研究了在分界点存在不连续霍普夫分岔的条件。最后,在数值模拟部分,我们在图灵模式上验证了我们的定理。我们还研究了参数变化对谣言传播的影响,并得出结论:心理抑制因子的增加会显著降低谣言的传播速度,从而为遏制谣言提供有效策略。为此,我们将实际数据拟合到我们的系统中,结果非常出色,证实了系统的有效性。
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引用次数: 0
Memory Maps with Elliptical Trajectories 椭圆轨迹的记忆映射
Pub Date : 2023-07-01 DOI: 10.1142/s0218127423300215
Ted Szylowiec, Pawel Góra
A family of maps with memory, parameterized by [Formula: see text], is shown to have either periodic trajectories or dense trajectories on ellipses which support absolutely continuous invariant measures. Furthermore, for [Formula: see text], i.e. [Formula: see text] with [Formula: see text] and [Formula: see text], all points except [Formula: see text] either go into a polygonal region centered at [Formula: see text] if [Formula: see text] is rational, or are attracted to an elliptical region having the same center, if [Formula: see text] is irrational. In the polygonal case, we examine a mechanism for the appearance of islands supporting absolutely continuous invariant measures.
一组具有记忆的映射,参数化为[公式:见文本],被证明在支持绝对连续不变测度的椭圆上具有周期轨迹或密集轨迹。此外,对于[公式:见文],即[公式:见文]与[公式:见文]和[公式:见文],如果[公式:见文]是有理的,则除[公式:见文]外的所有点要么进入以[公式:见文]为中心的多边形区域,要么被吸引到具有相同中心的椭圆区域,如果[公式:见文]是非理性的。在多边形情况下,我们研究了支持绝对连续不变测度的岛屿出现的机制。
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引用次数: 0
Homoclinic Bifurcations in a Class of Three-Dimensional Symmetric Piecewise Affine Systems 一类三维对称分段仿射系统的同斜分岔
Pub Date : 2023-07-01 DOI: 10.1142/s0218127423501110
Ruimin Liu, Minghao Liu, Tiantian Wu
Many physical and engineering systems have certain symmetric properties. Homoclinic orbits play an important role in studying the global dynamics of dynamical systems. This paper focuses on the existence and bifurcations of homoclinic orbits to a saddle in a class of three-dimensional one-parameter three-zone symmetric piecewise affine systems. Based on the analysis of the Poincaré maps, the systems have two types of limit cycles and do not have chaotic invariant sets near the homoclinic orbits. In addition, the paper provides a constant [Formula: see text] to study the homoclinic bifurcations to limit cycles for the case [Formula: see text]. Two examples with simulations of the homoclinic orbits and the limit cycles are given to illustrate the effectiveness of the results.
许多物理和工程系统具有一定的对称性质。同斜轨道在研究动力系统的整体动力学中起着重要的作用。研究了一类三维单参数三区对称分段仿射系统鞍形同斜轨道的存在性和分岔性。通过对庞卡罗映射的分析,得到系统有两类极限环,且在同斜轨道附近不存在混沌不变集。此外,本文还提供了一个常数[公式:见文]来研究这种情况下极限环的同斜分岔[公式:见文]。最后给出了两个同斜轨道和极限环的模拟实例,说明了所得结果的有效性。
{"title":"Homoclinic Bifurcations in a Class of Three-Dimensional Symmetric Piecewise Affine Systems","authors":"Ruimin Liu, Minghao Liu, Tiantian Wu","doi":"10.1142/s0218127423501110","DOIUrl":"https://doi.org/10.1142/s0218127423501110","url":null,"abstract":"Many physical and engineering systems have certain symmetric properties. Homoclinic orbits play an important role in studying the global dynamics of dynamical systems. This paper focuses on the existence and bifurcations of homoclinic orbits to a saddle in a class of three-dimensional one-parameter three-zone symmetric piecewise affine systems. Based on the analysis of the Poincaré maps, the systems have two types of limit cycles and do not have chaotic invariant sets near the homoclinic orbits. In addition, the paper provides a constant [Formula: see text] to study the homoclinic bifurcations to limit cycles for the case [Formula: see text]. Two examples with simulations of the homoclinic orbits and the limit cycles are given to illustrate the effectiveness of the results.","PeriodicalId":13688,"journal":{"name":"Int. J. Bifurc. Chaos","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85463618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Uncovering the Correlation Between Spindle and Ripple Dynamics and Synaptic Connections in a Hippocampal-Thalamic-Cortical Model 揭示海马-丘脑-皮质模型中纺锤体和纹波动力学与突触连接之间的相关性
Pub Date : 2023-07-01 DOI: 10.1142/s0218127423501092
S. Sriram, Hayder Natiq, K. Rajagopal, Fatemeh Parastesh, S. Jafari
Consolidation of new information in memory occurs through the simultaneous occurrence of sharp-wave ripples (SWR) in the hippocampus network, fast–slow spindles in the thalamus network, and up and down oscillations in the cortex network during sleep. Previous studies have investigated the influential and active role of spindles and sharp-wave ripples in memory consolidation. However, a detailed investigation of the effect of membrane voltage of neurons and synaptic connections between neurons in the cortex, hippocampus, and thalamus networks to create spindle and SWR is required. This paper studies the dynamic behaviors of a hippocampal-thalamic-cortical network as a function of synaptic connection between excitatory neurons, inhibitory neurons (in the hippocampus and cortex), reticular neurons, and thalamocortical neurons (in the thalamic network). The bifurcation diagrams of the hippocampus, cortex, and thalamus networks are obtained by varying the strengths of different synaptic connections. The power diagrams for SWR and sleep spindles are shown accordingly. The results show that variations in synaptic self-connection (and inhibitory synaptic connection) of excitatory neurons in the CA3 region, as well as synaptic connection between excitatory neurons from CA1 region to excitatory neurons (and inhibitory neurons) in the cortex network have the most significant influence on dynamical behavior of the network. Furthermore, comparing diagrams for different synaptic connections shows that SWR is formed by excitatory neurons in CA3 region of the hippocampal network, passes through CA1 region, and enters cortex network.
在睡眠中,新信息在记忆中的巩固是通过海马体网络中的锐波涟漪(SWR)、丘脑网络中的快慢纺锤波和皮层网络中的上下振荡同时发生的。以往的研究已经探讨了纺锤波和尖波涟漪在记忆巩固中的积极作用。然而,需要详细研究神经元的膜电压以及皮层、海马和丘脑网络中神经元之间的突触连接对产生纺锤体和SWR的影响。本文研究了兴奋性神经元、抑制性神经元(位于海马和皮层)、网状神经元和丘脑皮质神经元(位于丘脑网络)之间突触连接的动态行为。海马体、皮层和丘脑网络的分叉图是通过改变不同突触连接的强度得到的。SWR和睡眠纺锤体的功率图如图所示。结果表明,CA3区的兴奋性神经元突触自连接(和抑制性突触连接)以及CA1区的兴奋性神经元与皮层网络中的兴奋性神经元(和抑制性神经元)之间的突触连接的变化对网络的动态行为影响最为显著。此外,通过对比不同突触连接图可知,SWR由海马网络CA3区的兴奋性神经元形成,经CA1区进入皮层网络。
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引用次数: 1
Nonlinear Vibration Analysis of the Coupled Gear-Rotor-Bearing Transmission System for a New Energy Vehicle 新能源汽车齿轮-转子-轴承耦合传动系统非线性振动分析
Pub Date : 2023-07-01 DOI: 10.1142/s0218127423501055
Shuai Mo, Zhen Wang, Y. Zeng, Wei Zhang
Considering the effects of time-varying meshing stiffness, time-varying support stiffness, transmission errors, tooth side clearance and bearing clearance, a nonlinear dynamics model of the coupled gear-rotor-bearing transmission system of a new energy vehicle is constructed. Firstly, the fourth-order Runge–Kutta integral method is used to solve the differential equations of the system dynamics, and the time-varying meshing force diagram, time history diagram, phase diagram, FFT spectrum diagram, Poincaré map and bifurcation diagram of the system are obtained to study the influence of the external load excitation frequency on the dynamics characteristics of the system. In addition, the multiscale method is used to analyze the main resonance characteristics of the system and to determine the main resonance stability conditions of the system. The effect of time lag control parameters and external load excitation frequency on the main resonance of the system is analyzed by numerical methods. The results show that the gear-rotor-bearing coupled transmission system of the new energy vehicle has obviously nonlinear characteristics, avoiding the system instability interval reasonable selection of external load excitation frequency, meshing damping, time lag parameters and load fluctuations, which can be used to improve the stability of the transmission system of the new energy vehicle.
考虑时变啮合刚度、时变支承刚度、传动误差、齿侧间隙和轴承间隙的影响,建立了新能源汽车齿轮-转子-轴承耦合传动系统的非线性动力学模型。首先,采用四阶龙格-库塔积分法求解系统动力学微分方程,得到系统的时变啮合力图、时程图、相位图、FFT谱图、poincarcarcars图和分岔图,研究外部负载激励频率对系统动力学特性的影响。此外,采用多尺度法分析了系统的主共振特性,确定了系统的主共振稳定条件。采用数值方法分析了时滞控制参数和外部负载激励频率对系统主共振的影响。结果表明,新能源汽车齿轮-转子-轴承耦合传动系统具有明显的非线性特性,避免了系统失稳区间,合理选择外部负载激励频率、啮合阻尼、时滞参数和负载波动,可用于提高新能源汽车传动系统的稳定性。
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引用次数: 0
Solution Structures of an Electrical Transmission Line Model with Bifurcation and Chaos in Hamiltonian Dynamics 哈密顿动力学中具有分岔和混沌的输电线路模型的解结构
Pub Date : 2023-07-01 DOI: 10.1142/s0218127423501080
Jian-ming Qi, Q. Cui, Le Zhang, Yiqun Sun
Employing the Riccati–Bernoulli sub-ODE method (RBSM) and improved Weierstrass elliptic function method, we handle the proposed [Formula: see text]-dimensional nonlinear fractional electrical transmission line equation (NFETLE) system in this paper. An infinite sequence of solutions and Weierstrass elliptic function solutions may be obtained through solving the NFETLE. These new exact and solitary wave solutions are derived in the forms of trigonometric function, Weierstrass elliptic function and hyperbolic function. The graphs of soliton solutions of the NFETLE describe the dynamics of the solutions in the figures. We also discuss elaborately the effects of fraction and arbitrary parameters on a part of obtained soliton solutions which are presented graphically. Moreover, we also draw meaningful conclusions via a comparison of our partially explored areas with other different fractional derivatives. From our perspectives, by rewriting the equation as Hamiltonian system, we study the phase portrait and bifurcation of the system about NFETLE and we also for the first time discuss sensitivity of the system and chaotic behaviors. To our best knowledge, we discover a variety of new solutions that have not been reported in existing articles [Formula: see text], [Formula: see text]. The most important thing is that there are iterative ideas in finding the solution process, which have not been seen before from relevant articles such as [Tala-Tebue et al., 2014; Fendzi-Donfack et al., 2018; Ashraf et al., 2022; Ndzana et al., 2022; Halidou et al., 2022] in seeking for exact solutions about NFETLE.
本文采用riccti - bernoulli子ode方法(RBSM)和改进的Weierstrass椭圆函数方法,处理了所提出的[公式:见文]-维非线性分数阶输电线方程(NFETLE)系统。通过求解NFETLE可以得到无穷级数的解和weerstrass椭圆函数解。这些新的精确和孤立波解分别以三角函数、weerstrass椭圆函数和双曲函数的形式导出。NFETLE的孤子解的图形描述了图中解的动力学。我们还详细讨论了分数和任意参数对得到的部分孤子解的影响。此外,我们还通过比较我们部分探索的领域与其他不同的分数导数得出有意义的结论。从我们的角度出发,通过将方程改写为哈密顿系统,我们研究了NFETLE系统的相画像和分岔,并首次讨论了系统的灵敏度和混沌行为。据我们所知,我们发现了现有文章中没有报道的各种新的解决方案[公式:见文本],[公式:见文本]。最重要的是,在寻找解决方案的过程中有迭代的想法,这在之前的相关文章中没有见过,如[Tala-Tebue et al., 2014;Fendzi-Donfack et al., 2018;Ashraf et al., 2022;Ndzana et al., 2022;Halidou et al., 2022]寻求NFETLE的精确解。
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引用次数: 0
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Int. J. Bifurc. Chaos
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