Abstract
This paper proposes a new three-dimensional chaotic flow with one stable equilibrium. Dynamical properties of this system are investigated. The system has a chaotic attractor coexisting with a stable equilibrium. Thus the chaotic attractor is hidden. Basin of attractions shows the tangle of different attractors. Also, some complexity measures of the system such as Lyapunov exponent and entropy will are analyzed. We show that the Kolmogorov-Sinai Entropy shows more accurate results in comparison with Shanon Entropy.
1 Introduction
Chaotic systems and their dynamical properties are interesting topics in nonlinear dynamics. Small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for such dynamical systems, rendering long-term prediction of their behavior impossible in general. This happens even though these systems are deterministic, meaning that their future behavior is fully determined by their initial conditions, with no random elements involved. In other words, the deterministic nature of these systems does not make them predictable. This behavior is known as deterministic chaos, or simply chaos [1, 2, 3].
For many years, researchers have believed that a chaotic attractor is related to a saddle equilibrium [4, 5, 6, 7]. However it is clear now that the existence of a saddle point is not a necessary condition for existence of chaotic solutions. The reason is that recently many new chaotic systems have been proposed without any equilibria [8], with one stable equilibria [9], with a line of equilibria [10, 11], with a curve of equilibria [12, 13] and with a plane of equilibria [14]. It seems the relation between equilibria and their stable and unstable manifolds is unknown to us. From a point of view, attractors of dynamical systems have been categorized into two groups. The first one is hidden attractor. An attractor is called hidden if its basin of attraction does not intersect with a small neighborhood of any equilibrium point [15, 16, 17, 18]. The second one is self-excited attractor. An attractor is called self-excited if its basin of attraction is associated with an unstable equilibrium [19, 20, 21]. In the case of chaotic attractors in systems with a stable equilibrium, at least there are two attractors simultaneously (strange attractor and stable equilibrium attractor). These attractors are called multi-stable since the final state of the system is dependent on its initial condition [22, 23, 24, 25].
There are many features which measure the complexity of dynamical systems. Features such as Lyapunov exponents, Entropy, fractal dimension and correlation dimension [3, 26] are some examples of them. Also, these measures quantify chaotic attractors [3]. Entropy measure is the best when only a short time series of system is available [27]. In this paper, we propose a new three-dimensional chaotic flow with only one stable equilibrium. In this case the strange attractor is hidden, since the existence of an unstable equilibrium in its basin is impossible.
It should be noted that while there are many chaotic flows in the literature, only a little part of them are systems with hidden attractors. In that little part, only a few of them are systems with stable equilibria only. Another important aspect about our new proposed system is that it is multi-stable. Multistability is an important topic in nonlinear dynamics and chaos [28, 29, 30, 31, 32, 33]. In some occasions multistability is unwanted, while in some cases it is desired. When it is important in a dynamical system to work in a specific state and not go out from it, then multistability in that system is a potential danger (because due to any disturbance the system can go to a new unwanted situation). On the other hand, multistability makes systems flexible without tuning parameters [34]. In any case, better understanding of such systems may be of interest.
Chaotic systems with hidden attractors and multi-stability are very important in engineering and can be much challenging in applications like control [35, 36], synchronization [37, 38, 39, 40, 41, 42], anti-synchronization [43], image encryption [44, 45], and so on.
The aim of this paper is to
enrich the list of known chaotic systems with hidden attractors, especially systems with stable equilibrium (which are the rarest kind),
enrich the list of known chaotic systems with multistability and a better analysis of them by the help of looking at their basins of attraction,
comparing complexity measurement tools in order to determine better indexes when we deal with real time-series instead of systems’ equations.
The rest of the paper is organized as follows: the system’s attractors and their basins of attraction are discussed in Section 2. In Section 3 we do the bifurcation analysis for the proposed system. Entropy analysis of the system is investigated in Section 4. Finally, Section 5 concludes the paper.
2 System description
Consider the following general form of a three-dimensional chaotic flow,
This structure is inspired from system SE14 in Ref. [46]. Using trial and error by the help of computer, we tried to find a simple choice for f(x,y,z) with the following conditions:
The equation f(0, y, 0) = 0, should have only one solution, say y*, which means the system has only one equilibrium in (0, y*, 0).
That equilibrium must have only eigenvalues with negative real parts (which means it should be stable).
The system should have chaotic solution for some initial conditions.
We used a simple, but time consuming method. We produced random sets of parameters to find bounded oscillatory solutions. Then for the most elegant [47] results, we fixed all parameters but one, and changed that one manually seeking for the largest positive Lyapunov exponent. Finding the first chaotic solution, we tuned carefully all other parameters, trying to find more elegant values without losing the chaotic solution.
The simplest case we found is:
where x, y and z are variables and b is the system’s parameter. By setting zeros the right hand side of Eq. (2), the equilibria of the system can be obtained by Eq. (3)
So the system has an equilibrium point in the origin. In order to analyze its stability, we calculate the Jacobian matrix of the system in origin,
By solving ∣J – λI∣ = 0, characteristic equation is obtained by
Thus, the Eigenvalues are λ1 = –0.7942, λ2,3 = –0.1029 ± 2.2419i. It means that the origin is stable (spiral node, since it has three eigenvalues with negative real parts, and a pair of them is complex).
System (2) has a chaotic attractor for b = 0.4 (for e.g. initial conditions (3.95, –3.91, 3.17). Figure 1 shows three projections of this strange attractor. The system has only one equilibrium, which is stable. Thus, the strange attractor is hidden. Figure 2 shows basin of attraction of System (2) in the plane z = 0 for intervals x ∈ [–5, 40], y ∈ [–20, 5]. The red region in the figure shows initial conditions, which lead to the stable equilibrium. Initial conditions in the cyan region lead to chaotic attractor and initial conditions in the yellow region lead to unbounded orbits. Black point in the figure is the origin (which is the stable equilibrium). As the figure indicates the strange attractors of the system cannot be found with initial conditions near the origin. Therefore, strange attractor of the system is hidden.

Three projections of strange attractor of System (2) with initial conditions (3.95, –3.91, 3.17) a) in x-y plane, b) in x-z plane, c) in y-z plane.

Basin of attraction of System (2) for b = 0.4. Initial conditions in the red region lead to stable equilibria, initial conditions in the cyan region lead to strange attractor and initial conditions in the yellow region lead to unbounded orbits.
3 Bifurcation analysis
Bifurcation diagram is a helpful tool, which can exhibit different dynamical solutions of a system. Figure 3 shows bifurcation diagram of System (2) with respect to changing parameter b. The figure depicts that the system has an inverse period doubling route to chaos by increasing parameter b. Also the system has a jump from a limit cycle to its stable equilibria in b = 0.424. Lyapunov exponents diagram in Figure 4 proves different dynamics that can be seen in the bifurcation diagram. Also the jump from limit cycle to the fixed point can be detected in Lyapunov exponents diagram.
![Figure 3 Bifurcation diagram of System (2) with respect to changing parameter b in the interval [0.4, 0.44] and forward continuation.](/document/doi/10.1515/phys-2018-0037/asset/graphic/j_phys-2018-0037_fig_003.jpg)
Bifurcation diagram of System (2) with respect to changing parameter b in the interval [0.4, 0.44] and forward continuation.
![Figure 4 Three Lyapunov exponents of System (2) with respect to changing parameter b in the interval [0.4, 0.44].](/document/doi/10.1515/phys-2018-0037/asset/graphic/j_phys-2018-0037_fig_004.jpg)
Three Lyapunov exponents of System (2) with respect to changing parameter b in the interval [0.4, 0.44].
4 Entropy analysis
Entropy is a measure of unpredictability [48]. For the first time, Boltzmann defined it mathematically. Then Shannon defined a more general way for measuring the entropy [49]. Its definition is as follows,
where ρi is the probability of every possible i states. As bifurcation diagram of Figure 3 shows, the system has an inverse period doubling route to chaos by increasing parameter b. So, the system has more complex dynamic in lower values of parameter b and more simple dynamic in larger values. Figure 5 shows entropy of System (2) with respect to changing parameter b. The entropy is calculated using Eq. (6) and the Poincaré section of the system’s time series (peaks of x) in each parameter b. The figure shows that the complexity of dynamic is decreased by increasing parameter b and the dynamic becomes more predictable. Also, the system shows decreasing in the complexity of the periodic window near the parameter b = 0.402 (as can be seen in the Lyapunov exponent).

Entropy of System (2) with respect to changing parameter b. It is calculated using peaks of x and runtime = 20000. Initial conditions are selected with forward continuation.
In non-periodic attractors, there are infinite number of states in partitions of phase space. So, it is pointless to study the entropy of Eq. (6). In other words, the entropy should be measured relative to another trajectory and per unit of time [27]. Therefore, a new entropy measure is defined as Eq. (7). The entropy is defined using the first Poincaré recurrence times (FPRs) denoted by τi,
β is a D-dimensional box in the phase space with side ε1 where the FPRs are observed. ρ (τ, β) is the probability distribution of τi. The entropy is called Kolmogorov-Sinai [27, 50]. It has been proved that for a smooth chaotic system HKS is equal to the sum of all positive Lyapunov exponents [51, 52]. Figure 6 shows the Kolmogorov-Sinai entropy with respect to changing parameter b. This entropy shows a more proper view about complexity of the system. It depicts that in high values of parameter b there are no positive Lyapunov exponents and so the Entropy is zero. Also, it shows a peak in the bifurcation point from period two to period one. Also decreasing the complexity of system in the inverse route of period doubling can be seen in Figure 5.

Kolmogorov-Sinai Entropy of System (2) with respect to changing parameter b. It is calculated using peaks of x and runtime = 20000. Initial conditions are selected with forward continuation.
5 Conclusion
In this paper a new three-dimensional chaotic flow has been proposed. The system had a stable equilibrium point. Thus, its chaotic attractor was hidden. Dynamical analysis of the system has shown an inverse period doubling route to chaos with respect to increasing its parameter. Positive Lyapunov exponent has proved the presence of chaos in this dynamical system. Entropy analysis of the system was done to investigate the predictability of the dynamics using only its time series. We showed that the Kolmogorov-Sinai entropy shows more accurate results in comparison with Shanon entropy.
Acknowledgement
TK has been supported by the Polish National Science Centre, MAESTRO Programme-Project No. 2013/327 08/A/ST8/00/780.
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- A method to reduce partial discharges in motor windings fed by PWM inverter
- Reluctance network lumped mechanical & thermal models for the modeling and predesign of concentrated flux synchronous machine
- Special Issue Applications of Nonlinear Dynamics
- Study on dynamic characteristics of silo-stock-foundation interaction system under seismic load
- Microblog topic evolution computing based on LDA algorithm
- Modeling the creep damage effect on the creep crack growth behavior of rotor steel
- Neighborhood condition for all fractional (g, f, n′, m)-critical deleted graphs
- Chinese open information extraction based on DBMCSS in the field of national information resources
- 10.1515/phys-2018-0079
- CPW-fed circularly-polarized antenna array with high front-to-back ratio and low-profile
- Intelligent Monitoring Network Construction based on the utilization of the Internet of things (IoT) in the Metallurgical Coking Process
- Temperature detection technology of power equipment based on Fiber Bragg Grating
- Research on a rotational speed control strategy of the mandrel in a rotary steering system
- Dynamic load balancing algorithm for large data flow in distributed complex networks
- Super-structured photonic crystal fiber Bragg grating biosensor image model based on sparse matrix
- Fractal-based techniques for physiological time series: An updated approach
- Analysis of the Imaging Characteristics of the KB and KBA X-ray Microscopes at Non-coaxial Grazing Incidence
- Application of modified culture Kalman filter in bearing fault diagnosis
- Exact solutions and conservation laws for the modified equal width-Burgers equation
- On topological properties of block shift and hierarchical hypercube networks
- Elastic properties and plane acoustic velocity of cubic Sr2CaMoO6 and Sr2CaWO6 from first-principles calculations
- A note on the transmission feasibility problem in networks
- Ontology learning algorithm using weak functions
- Diagnosis of the power frequency vacuum arc shape based on 2D-PIV
- Parametric simulation analysis and reliability of escalator truss
- A new algorithm for real economy benefit evaluation based on big data analysis
- Synergy analysis of agricultural economic cycle fluctuation based on ant colony algorithm
- Multi-level encryption algorithm for user-related information across social networks
- Multi-target tracking algorithm in intelligent transportation based on wireless sensor network
- Fast recognition method of moving video images based on BP neural networks
- Compressed sensing image restoration algorithm based on improved SURF operator
- Design of load optimal control algorithm for smart grid based on demand response in different scenarios
- Face recognition method based on GA-BP neural network algorithm
- Optimal path selection algorithm for mobile beacons in sensor network under non-dense distribution
- Localization and recognition algorithm for fuzzy anomaly data in big data networks
- Urban road traffic flow control under incidental congestion as a function of accident duration
- Optimization design of reconfiguration algorithm for high voltage power distribution network based on ant colony algorithm
- Feasibility simulation of aseismic structure design for long-span bridges
- Construction of renewable energy supply chain model based on LCA
- The tribological properties study of carbon fabric/ epoxy composites reinforced by nano-TiO2 and MWNTs
- A text-Image feature mapping algorithm based on transfer learning
- Fast recognition algorithm for static traffic sign information
- Topical Issue: Clean Energy: Materials, Processes and Energy Generation
- An investigation of the melting process of RT-35 filled circular thermal energy storage system
- Numerical analysis on the dynamic response of a plate-and-frame membrane humidifier for PEMFC vehicles under various operating conditions
- Energy converting layers for thin-film flexible photovoltaic structures
- Effect of convection heat transfer on thermal energy storage unit
Articles in the same Issue
- Regular Articles
- A modified Fermi-Walker derivative for inextensible flows of binormal spherical image
- Algebraic aspects of evolution partial differential equation arising in the study of constant elasticity of variance model from financial mathematics
- Three-dimensional atom localization via probe absorption in a cascade four-level atomic system
- Determination of the energy transitions and half-lives of Rubidium nuclei
- Three phase heat and mass transfer model for unsaturated soil freezing process: Part 1 - model development
- Three phase heat and mass transfer model for unsaturated soil freezing process: Part 2 - model validation
- Mathematical model for thermal and entropy analysis of thermal solar collectors by using Maxwell nanofluids with slip conditions, thermal radiation and variable thermal conductivity
- Constructing analytic solutions on the Tricomi equation
- Feynman diagrams and rooted maps
- New type of chaos synchronization in discrete-time systems: the F-M synchronization
- Unsteady flow of fractional Oldroyd-B fluids through rotating annulus
- A note on the uniqueness of 2D elastostatic problems formulated by different types of potential functions
- On the conservation laws and solutions of a (2+1) dimensional KdV-mKdV equation of mathematical physics
- Computational methods and traveling wave solutions for the fourth-order nonlinear Ablowitz-Kaup-Newell-Segur water wave dynamical equation via two methods and its applications
- Siewert solutions of transcendental equations, generalized Lambert functions and physical applications
- Numerical solution of mixed convection flow of an MHD Jeffery fluid over an exponentially stretching sheet in the presence of thermal radiation and chemical reaction
- A new three-dimensional chaotic flow with one stable equilibrium: dynamical properties and complexity analysis
- Dynamics of a dry-rebounding drop: observations, simulations, and modeling
- Modeling the initial mechanical response and yielding behavior of gelled crude oil
- Lie symmetry analysis and conservation laws for the time fractional simplified modified Kawahara equation
- Solitary wave solutions of two KdV-type equations
- Applying industrial tomography to control and optimization flow systems
- Reconstructing time series into a complex network to assess the evolution dynamics of the correlations among energy prices
- An optimal solution for software testing case generation based on particle swarm optimization
- Optimal system, nonlinear self-adjointness and conservation laws for generalized shallow water wave equation
- Alternative methods for solving nonlinear two-point boundary value problems
- Global model simulation of OH production in pulsed-DC atmospheric pressure helium-air plasma jets
- Experimental investigation on optical vortex tweezers for microbubble trapping
- Joint measurements of optical parameters by irradiance scintillation and angle-of-arrival fluctuations
- M-polynomials and topological indices of hex-derived networks
- Generalized convergence analysis of the fractional order systems
- Porous flow characteristics of solution-gas drive in tight oil reservoirs
- Complementary wave solutions for the long-short wave resonance model via the extended trial equation method and the generalized Kudryashov method
- A Note on Koide’s Doubly Special Parametrization of Quark Masses
- On right-angled spherical Artin monoid of type Dn
- Gas flow regimes judgement in nanoporous media by digital core analysis
- 4 + n-dimensional water and waves on four and eleven-dimensional manifolds
- Stabilization and Analytic Approximate Solutions of an Optimal Control Problem
- On the equations of electrodynamics in a flat or curved spacetime and a possible interaction energy
- New prediction method for transient productivity of fractured five-spot patterns in low permeability reservoirs at high water cut stages
- The collinear equilibrium points in the restricted three body problem with triaxial primaries
- Detection of the damage threshold of fused silica components and morphologies of repaired damage sites based on the beam deflection method
- On the bivariate spectral quasi-linearization method for solving the two-dimensional Bratu problem
- Ion acoustic quasi-soliton in an electron-positron-ion plasma with superthermal electrons and positrons
- Analysis of projectile motion in view of conformable derivative
- Computing multiple ABC index and multiple GA index of some grid graphs
- Terahertz pulse imaging: A novel denoising method by combing the ant colony algorithm with the compressive sensing
- Characteristics of microscopic pore-throat structure of tight oil reservoirs in Sichuan Basin measured by rate-controlled mercury injection
- An activity window model for social interaction structure on Twitter
- Transient thermal regime trough the constitutive matrix applied to asynchronous electrical machine using the cell method
- On the zagreb polynomials of benzenoid systems
- Integrability analysis of the partial differential equation describing the classical bond-pricing model of mathematical finance
- The Greek parameters of a continuous arithmetic Asian option pricing model via Laplace Adomian decomposition method
- Quantifying the global solar radiation received in Pietermaritzburg, KwaZulu-Natal to motivate the consumption of solar technologies
- Sturm-Liouville difference equations having Bessel and hydrogen atom potential type
- Study on the response characteristics of oil wells after deep profile control in low permeability fractured reservoirs
- Depiction and analysis of a modified theta shaped double negative metamaterial for satellite application
- An attempt to geometrize electromagnetism
- Structure of traveling wave solutions for some nonlinear models via modified mathematical method
- Thermo-convective instability in a rotating ferromagnetic fluid layer with temperature modulation
- Construction of new solitary wave solutions of generalized Zakharov-Kuznetsov-Benjamin-Bona-Mahony and simplified modified form of Camassa-Holm equations
- Effect of magnetic field and heat source on Upper-convected-maxwell fluid in a porous channel
- Physical cues of biomaterials guide stem cell fate of differentiation: The effect of elasticity of cell culture biomaterials
- Shooting method analysis in wire coating withdrawing from a bath of Oldroyd 8-constant fluid with temperature dependent viscosity
- Rank correlation between centrality metrics in complex networks: an empirical study
- Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering
- Modeling of electric and heat processes in spot resistance welding of cross-wire steel bars
- Dynamic characteristics of triaxial active control magnetic bearing with asymmetric structure
- Design optimization of an axial-field eddy-current magnetic coupling based on magneto-thermal analytical model
- Thermal constitutive matrix applied to asynchronous electrical machine using the cell method
- Temperature distribution around thin electroconductive layers created on composite textile substrates
- Model of the multipolar engine with decreased cogging torque by asymmetrical distribution of the magnets
- Analysis of spatial thermal field in a magnetic bearing
- Use of the mathematical model of the ignition system to analyze the spark discharge, including the destruction of spark plug electrodes
- Assessment of short/long term electric field strength measurements for a pilot district
- Simulation study and experimental results for detection and classification of the transient capacitor inrush current using discrete wavelet transform and artificial intelligence
- Magnetic transmission gear finite element simulation with iron pole hysteresis
- Pulsed excitation terahertz tomography – multiparametric approach
- Low and high frequency model of three phase transformer by frequency response analysis measurement
- Multivariable polynomial fitting of controlled single-phase nonlinear load of input current total harmonic distortion
- Optimal design of a for middle-low-speed maglev trains
- Eddy current modeling in linear and nonlinear multifilamentary composite materials
- The visual attention saliency map for movie retrospection
- AC/DC current ratio in a current superimposition variable flux reluctance machine
- Influence of material uncertainties on the RLC parameters of wound inductors modeled using the finite element method
- Cogging force reduction in linear tubular flux switching permanent-magnet machines
- Modeling hysteresis curves of La(FeCoSi)13 compound near the transition point with the GRUCAD model
- Electro-magneto-hydrodynamic lubrication
- 3-D Electromagnetic field analysis of wireless power transfer system using K computer
- Simplified simulation technique of rotating, induction heated, calender rolls for study of temperature field control
- Design, fabrication and testing of electroadhesive interdigital electrodes
- A method to reduce partial discharges in motor windings fed by PWM inverter
- Reluctance network lumped mechanical & thermal models for the modeling and predesign of concentrated flux synchronous machine
- Special Issue Applications of Nonlinear Dynamics
- Study on dynamic characteristics of silo-stock-foundation interaction system under seismic load
- Microblog topic evolution computing based on LDA algorithm
- Modeling the creep damage effect on the creep crack growth behavior of rotor steel
- Neighborhood condition for all fractional (g, f, n′, m)-critical deleted graphs
- Chinese open information extraction based on DBMCSS in the field of national information resources
- 10.1515/phys-2018-0079
- CPW-fed circularly-polarized antenna array with high front-to-back ratio and low-profile
- Intelligent Monitoring Network Construction based on the utilization of the Internet of things (IoT) in the Metallurgical Coking Process
- Temperature detection technology of power equipment based on Fiber Bragg Grating
- Research on a rotational speed control strategy of the mandrel in a rotary steering system
- Dynamic load balancing algorithm for large data flow in distributed complex networks
- Super-structured photonic crystal fiber Bragg grating biosensor image model based on sparse matrix
- Fractal-based techniques for physiological time series: An updated approach
- Analysis of the Imaging Characteristics of the KB and KBA X-ray Microscopes at Non-coaxial Grazing Incidence
- Application of modified culture Kalman filter in bearing fault diagnosis
- Exact solutions and conservation laws for the modified equal width-Burgers equation
- On topological properties of block shift and hierarchical hypercube networks
- Elastic properties and plane acoustic velocity of cubic Sr2CaMoO6 and Sr2CaWO6 from first-principles calculations
- A note on the transmission feasibility problem in networks
- Ontology learning algorithm using weak functions
- Diagnosis of the power frequency vacuum arc shape based on 2D-PIV
- Parametric simulation analysis and reliability of escalator truss
- A new algorithm for real economy benefit evaluation based on big data analysis
- Synergy analysis of agricultural economic cycle fluctuation based on ant colony algorithm
- Multi-level encryption algorithm for user-related information across social networks
- Multi-target tracking algorithm in intelligent transportation based on wireless sensor network
- Fast recognition method of moving video images based on BP neural networks
- Compressed sensing image restoration algorithm based on improved SURF operator
- Design of load optimal control algorithm for smart grid based on demand response in different scenarios
- Face recognition method based on GA-BP neural network algorithm
- Optimal path selection algorithm for mobile beacons in sensor network under non-dense distribution
- Localization and recognition algorithm for fuzzy anomaly data in big data networks
- Urban road traffic flow control under incidental congestion as a function of accident duration
- Optimization design of reconfiguration algorithm for high voltage power distribution network based on ant colony algorithm
- Feasibility simulation of aseismic structure design for long-span bridges
- Construction of renewable energy supply chain model based on LCA
- The tribological properties study of carbon fabric/ epoxy composites reinforced by nano-TiO2 and MWNTs
- A text-Image feature mapping algorithm based on transfer learning
- Fast recognition algorithm for static traffic sign information
- Topical Issue: Clean Energy: Materials, Processes and Energy Generation
- An investigation of the melting process of RT-35 filled circular thermal energy storage system
- Numerical analysis on the dynamic response of a plate-and-frame membrane humidifier for PEMFC vehicles under various operating conditions
- Energy converting layers for thin-film flexible photovoltaic structures
- Effect of convection heat transfer on thermal energy storage unit