Hyperchaotic Behavior Research Articles

Qualitative Analysis of Class of Fractional-Order Chaotic System via Bifurcation and Lyapunov Exponents Notions

This paper presents a modified chaotic system under the fractional operator with singularity. The aim of the present subject will be to focus on the influence of the new model’s parameters and its fractional order using the bifurcation diagrams and the Lyapunov exponents. The new fractional model will generate chaotic behaviors. The Lyapunov exponents’ theories in fractional context will be used for the characterization of the chaotic behaviors. In a fractional context, the phase portraits will be obtained with a predictor-corrector numerical scheme method. The details of the numerical scheme will be presented in this paper. The numerical scheme will be used to analyze all the properties addressed in this present paper. The Matignon criterion will also play a fundamental role in the local stability of the presented model’s equilibrium points. We will find a threshold under which the stability will be removed and the chaotic and hyperchaotic behaviors will be generated. An adaptative control will be proposed to correct the instability of the equilibrium points of the model. Sensitive to the initial conditions, we will analyze the influence of the initial conditions on our fractional chaotic system. The coexisting attractors will also be provided for illustrations of the influence of the initial conditions.

Chaos and Hyperchaos in a Ka-Band Gyrotron

We present the first experimental proof of hyperchaotic regimes in a gyrotron. Based on experimental data analysis, we calculate the spectrum of Lyapunov exponents and estimate the correlation dimension of the attractors in non-stationary regimes of oscillation of a Ka-band gyrotron. We prove the existence of chaotic and hyperchaotic behavior characterized by one and two positive Lyapunov exponents, respectively. Estimations of dimensions of the obtained attractors show the values higher than 4 in the developed chaos regimes.

Random matrix ensembles in hyperchaotic classical dissipative dynamic systems

We study the statistical fluctuations of Lyapunov exponents in the discrete version of the non-integrable perturbed sine-Gordon equation, the dissipative AC- and DC-driven Frenkel–Kontorova model. Our analysis shows that the fluctuations of the exponent spacings in the strictly overdamped limit, which is nonchaotic, conform to an uncorrelated Poisson distribution. By studying the spatiotemporal dynamics, we relate the emergence of the Poissonian statistics to Middleton’s no-passing rule. Next, by scanning values of the DC drive and the particle mass, we identify several parameter regions for which this one-dimensional model exhibits hyperchaotic behavior. Furthermore, in the hyperchaotic regime where roughly fifty percent of the exponents are positive, the fluctuations exhibit features of the correlated universal statistics of the Gaussian orthogonal ensemble (GOE). Due to the dissipative nature of the dynamics, we find that the match between the Lyapunov spectrum statistics and the universal statistics of GOE is not complete. Finally, we present evidence supporting the existence of the Tracy–Widom distribution in the fluctuation statistics of the largest Lyapunov exponent.

Nonparametric Bifurcation and Anti-Control of Hyperchaos in a Memristor–Memcapacitor-Based Circuit

In this paper, a new memristor model and a new memcapacitor model are proposed. Based on the two models, a simple chaotic circuit is constructed. Due to the special characteristics of the memristor and memcapacitor, the proposed circuit has two-dimensional normally hyperbolic manifolds of equilibria, and nonparametric bifurcation can occur when the conditions supporting the normal hyperbolicity of such manifolds are not satisfied. By adding a nonlinear controller to the proposed circuit, an anti-controlled system is realized, which has hyperchaotic dynamic behaviors under some suitable control parameters. The stability of equilibrium points and dynamic properties of the original system and the anti-controlled system are explored by Lyapunov exponents, bifurcation diagrams and so on. Furthermore, the anti-controlled system is applied to design a random sequence generator on digital signal processor platform.

Hyperchaotic behaviors, optimal control, and synchronization of a nonautonomous cardiac conduction system

In this paper, the hyperchaos analysis, optimal control, and synchronization of a nonautonomous cardiac conduction system are investigated. We mainly analyze, control, and synchronize the associated hyperchaotic behaviors using several approaches. More specifically, the related nonlinear mathematical model is firstly introduced in the forms of both integer- and fractional-order differential equations. Then the related hyperchaotic attractors and phase portraits are analyzed. Next, effectual optimal control approaches are applied to the integer- and fractional-order cases in order to overcome the obnoxious hyperchaotic performance. In addition, two identical hyperchaotic oscillators are synchronized via an adaptive control scheme and an active controller for the integer- and fractional-order mathematical models, respectively. Simulation results confirm that the new nonlinear fractional model shows a more flexible behavior than its classical counterpart due to its memory effects. Numerical results are also justified theoretically, and computational experiments illustrate the efficacy of the proposed control and synchronization strategies.

Hyperchaotic Modulation for Secure Biomedical Signal Transmission

Abstract Nonlinear systems with hyperchaotic dynamical behaviour are studied for applications in complex measurement, modulation and encryption. Unidimensional signals resulting from medical tests can be securely transmitted using chaotic encryption. The present paper analyses synchronization of hyperchaotic systems applied in secure communication. The resulting emitter-receiver pair performance is presented from both dynamic and statistic points of view. Possible application in biomedical signal transmission is analyzed by computer simulations.

A novel fractional nonautonomous chaotic circuit model and its application to image encryption

Abstract A novel fractional nonautonomous system is proposed by introducing fractional order meminductor-memristor based circuit. Four circuit models are presented by different arrangements for the elements and the dynamic behaviors for each circuit are explored. It is observed that the four systems exhibit chaotic and hyperchaotic behaviors which have been verified using Lyapunov exponents. Bifurcation diagrams and phase portraits are employed to examine the effects of parameters variation on the qualitative dynamics of each model. An image encryption scheme is presented based on pseudo chaos orbit generated by two interval extensions of chaotic circuit model. The security analysis is carried out to verify the robustness and efficiency of the encryption scheme against possible attacks.

Hyperchaotic Self-Oscillations of Two-Stage Class C Amplifier With Generalized Transistors

This paper yields process of development, numerical analysis, lumped circuit modeling, and experimental verification of a new hyperchaotic oscillator based on the fundamental topology of two-stage amplifier. Analyzed network structure contains two generalized bipolar transistors connected with common emitter. Both transistors are initially modeled as two-ports via full admittance matrix, considering linear backward trans-conductance and polynomial forward trans-conductance. As proved in paper, these two scalar nonlinearities can push amplifier to exhibit robust hyperchaotic behavior with significantly high Kaplan-Yorke dimension. Regions of chaos and hyperchaos in a space of admittance parameters associated with both transistors are specified following the concept of positive values of Lyapunov exponents. Long time structural stability of generated hyperchaotic waveforms is proved by construction of flow-equivalent electronic circuit and experimental measurement, that is by screenshots captured by oscilloscope.

Compilation of a Coupled Hyper-Chaotic Lorenz System Based on DNA Strand Displacement Reaction Network.

Ideal formal chemical reaction network is an effective programming language to design complex system dynamical behavior. In this article, a coupled hyper-chaotic Lorenz system can be described by the ordinary differential equations of an ideal formal reaction network, which is constructed by catalysis, annihilation and adjust reaction modules, where the variables of system are represented by the difference in concentration of two chemical species. The ideal formal reaction network can be implemented by DNA strand displacement reaction network. Through Lyapunov exponent, we have analyzed hyper-chaotic dynamical behavior of coupled Lorenz system. In discussion and analysis, we have analyzed effect of noise, reaction rate control error and concentration detection error to DNA strand displacement reaction network.

An Innovative Way to Generate Hamiltonian Energy of a New Hyperchaotic Complex Nonlinear Model and Its Control

We are implementing a new Rabinovich hyperchaotic structure with complex variables in this research. This modern system is a real, autonomous hyperchaotic, and 8-dimensional continuous structure. Some of the characteristics of this system, as well as for invariance, dissipation, balance, and stability, are technically analyzed. Some other properties are also studied numerically, such as Lyapunov exponents, Lyapunov dimension, bifurcation diagrams, and chaotic actions. Hamiltonian energy is being studied and applying by using the innovative method. Via active control method, we inhibit our system’s hyperchaotic behavior. The new system’s hyperchaotic solutions are transformed into its unstable, trivial fixed point. The validity of the findings obtained is illustrated by an example of numerics and reenactment. Numerical results are plotted to display the variables of the state after and before the control to demonstrate that the control is being achieved.

Analysis of a fractional-order chaotic system in the context of the Caputo fractional derivative via bifurcation and Lyapunov exponents

This research focuses on the characterization of the chaotic behaviors, the hyperchaotic behaviors, and the impact of the fractional-order derivative in a class of fractional chaotic system. The numerical scheme, including the discretization of the Riemann–Liouville derivative, will be used to depict the phase portraits of the fractional-order chaotic system when the order of the used fractional-order derivative takes different values. The impact of the fractional-order derivative in the fractional chaotic system will be investigated. The proposed numerical scheme proposes a new alternative to obtain the phase portraits of the fractional-order chaotic systems. The sensitivity of the chaotic systems to the changes in the initial condition and the variation of the parameters of the considered model will be focussed with precision using the bifurcation diagrams and the Lyapunov exponent. The stability of the equilibrium points of the commensurable fractional-order chaotic system will be addressed in the context of fractional calculus. In other words, we will use the standard Matignon criterion to address the problem of stability. The main attraction and novelty of this paper will be the use of the Lyapunov exponent to characterize the nature of chaos and to prove the dissipativity of the considered chaotic system.

Analysis of a Four-Dimensional Hyperchaotic System Described by the Caputo–Liouville Fractional Derivative

A new four-dimensional hyperchaotic financial model is introduced. The novelties come from the fractional-order derivative and the use of the quadric function x 4 in modeling accurately the financial market. The existence and uniqueness of its solutions have been investigated to justify the physical adequacy of the model and the numerical scheme proposed in the resolution. We offer a numerical scheme of the new four-dimensional fractional hyperchaotic financial model. We have used the Caputo–Liouville fractional derivative. The problems addressed in this paper have much importance to approach the interest rate, the investment demand, the price exponent, and the average profit margin. The validation of the chaotic, hyperchaotic, and periodic behaviors of the proposed model, the bifurcation diagrams, the Lyapunov exponents, and the stability analysis has been analyzed in detail. The proposed numerical scheme for the hyperchaotic financial model is destined to help the agents decide in the financial market. The solutions of the 4D fractional hyperchaotic financial model have been analyzed, interpreted theoretically, and represented graphically in different contexts. The present paper is mathematical modeling and is a new tool in economics and finance. We also confirm, as announced in the literature, there exist hyperchaotic systems in the fractional context, which admit one positive Lyapunov exponent.

On Class of Fractional-Order Chaotic or Hyperchaotic Systems in the Context of the Caputo Fractional-Order Derivative

In this paper, we consider a class of fractional-order systems described by the Caputo derivative. The behaviors of the dynamics of this particular class of fractional-order systems will be proposed and experienced by a numerical scheme to obtain the phase portraits. Before that, we will provide the conditions under which the considered fractional-order system’s solution exists and is unique. The fractional-order impact will be analyzed, and the advantages of the fractional-order derivatives in modeling chaotic systems will be discussed. How the parameters of the model influence the considered fractional-order system will be studied using the Lyapunov exponents. The topological changes of the systems and the detection of the chaotic and hyperchaotic behaviors at the assumed initial conditions and the considered fractional-order systems will also be investigated using the Lyapunov exponents. The investigations related to the Lyapunov exponents in the context of the fractional-order derivative will be the main novelty of this paper. The stability analysis of the model’s equilibrium points has been focused in terms of the Matignon criterion.

A New Hyperchaotic Map for a Secure Communication Scheme with an Experimental Realization

Using different chaotic systems in secure communication, nonlinear control, and many other applications has revealed that these systems have several drawbacks in different aspects. This can cause unfavorable effects to chaos-based applications. Therefore, presenting a chaotic map with complex behaviors is considered important. In this paper, we introduce a new 2D chaotic map, namely, the 2D infinite-collapse-Sine model (2D-ICSM). Various metrics including Lyapunov exponents and bifurcation diagrams are used to demonstrate the complex dynamics and robust hyperchaotic behavior of the 2D-ICSM. Furthermore, the cross-correlation coefficient, phase space diagram, and Sample Entropy algorithm prove that the 2D-ICSM has a high sensitivity to initial values and parameters, extreme complexity performance, and a much larger hyperchaotic range than existing maps. To empirically verify the efficiency and simplicity of the 2D-ICSM in practical applications, we propose a symmetric secure communication system using the 2D-ICSM. Experimental results are presented to demonstrate the validity of the proposed system.

Dynamic Analysis and Circuit Realization of a Novel No-Equilibrium 5D Memristive Hyperchaotic System with Hidden Extreme Multistability

In this paper, a novel no-equilibrium 5D memristive hyperchaotic system is proposed, which is achieved by introducing an ideal flux-controlled memristor model and two constant terms into an improved 4D self-excited hyperchaotic system. The system parameters-dependent and memristor initial conditions-dependent dynamical characteristics of the proposed memristive hyperchaotic system are investigated in terms of phase portrait, Lyapunov exponent spectrum, bifurcation diagram, Poincaré map, and time series. Then, the hidden dynamic attractors such as periodic, quasiperiodic, chaotic, and hyperchaotic attractors are found under the variation of its system parameters. Meanwhile, the most striking phenomena of hidden extreme multistability, transient hyperchaotic behavior, and offset boosting control are revealed for appropriate sets of the memristor and other initial conditions. Finally, a hardware electronic circuit is designed, and the experimental results are well consistent with the numerical simulations, which demonstrate the feasibility of this novel 5D memristive hyperchaotic system.

Control and synchronization of the hyperchaotic attractor for a 5-D self-exciting homopolar disc dynamo

The control of the novel five-dimensional hidden attractors hyperchaotic system is investigated. We suggest an approach to change the model of its hyperchaotic behavior to an unpredictable trivial fixed point employing the stability principle. We are also researching the synchronization of the same system, focusing on the stability theory. Numerical simulations show that effective control and synchronization results are obtained with the control method.

Hyperchaos in a second‐order discrete memristor‐based map model

This Letter presents a new second-order discrete map model, which is derived from a simple sampling switch-based memristor-capacitor circuit. The memristor-based map model has infinite unstable and critical stable fixed points, and exhibits chaotic and hyperchaotic behaviours via a period-doubling bifurcation scenario. These complex dynamical behaviours are confirmed by the phase portraits, iterative sequences and basins of attraction.

A new adaptive synchronization and hyperchaos control of a biological snap oscillator

• Chaos control and synchronization of a biological snap oscillator is investigated. • Optimal and adaptive controllers are designed to overcome hyperchaotic behaviors. • An adaptive control scheme is introduced to synchronize two identical snap oscillators. • A new fractional model is developed for the biological system under study. • Efficient control strategies are used in fractional sense for the purpose of control and synchronization. The purpose of this paper is to analyze and control the hyperchaotic behaviours of a biological snap oscillator. We mainly study the chaos control and synchronization of a hyperchaotic model in both the frameworks of classical and fractional calculus, respectively. First, the phase portraits of the considered model and its hyperchaotic attractors are analyzed. Then two efficacious optimal and adaptive controllers are designed to compensate the undesirable hyperchaotic behaviours. Moreover, applying an efficient adaptive control procedure, we generally synchronize two identical biological snap oscillator models. Finally, a new fractional model is proposed for the considered oscillator in order to acquire the hyperchaotic attractors. Indeed, the fractional calculus leads to more realistic and flexible models with memory effects, which could help us to design more efficient controllers. Considering this feature, we apply a linear state-feedback controller as well as an active control scheme to control hyperchaos and achieve synchronization, respectively. The related theoretical consequences are numerically justified via the obtained simulations and experiments.

Modeling, Synchronization, and FPGA Implementation of Hamiltonian Conservative Hyperchaos

Conservative chaotic systems have potentials in engineering application because of their superiority over the dissipative systems in terms of ergodicity and integer dimension. In this paper, five-dimension Euler equations are constructed by integrating two of sub-Euler equations, which are contributory to the exploration of higher-dimensional systems. These Euler equations compose the conservative parts from their antisymmetric structure, which have been proved to be both Hamiltonian and Casimir energy conservative. Furthermore, a family of Hamiltonian conservative hyperchaotic systems are proposed by breaking the conservation of Casimir energy. The numerical analysis shows that the system displays some interesting behaviors, such as the coexistence of quasi-periodic, chaotic, and hyperchaotic behaviors. Adaptive synchronization method is used to realize the hyperchaos synchronization. Finally, the system passed the NIST tests successfully. Field programmable gate array (FPGA) platform is used to implement the proposed Hamiltonian conservative hyperchaos.

Efficient image encryption using two-dimensional enhanced hyperchaotic Henon map

We develop a two-dimensional enhanced hyperchaotic Henon map (2D-EHHM) to overcome the problems of small chaotic range and poor security when the 2-D traditional Henon map is implemented in cryptosystems. The performance evaluations show that the 2D-EHHM has wider chaotic range, higher chaotic complexity, better ergodicity, and hyperchaotic behavior compared with certain existing chaotic maps. Based on the 2D-EHHM, we further design an efficient image encryption algorithm consisting of a multiple block substitution stage (MBSS) and a bidirectional-dynamic diffusion stage (BDDS). In the MBSS, a plain image is divided into several nonoverlapping multiple blocks to carry out permutation operation. In the BDDS, the scrambled image is redivided into nonoverlapping sub-blocks of the same size to be diffused dynamically in the forward and backward directions. Moreover, the SHA 512 function is employed to obtain a 512-bit plain image hash value treated as a raw key. A variable-length secret key (at least 128 bits), which is dynamically selected from the raw key and regarded as a valid key, is utilized to generate the initial values for the chaotic system. Simulation results and security analysis show that the proposed algorithm can resist various cryptanalytic attacks and can be applied to real-time data transmission.