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This paper focuses on the species interaction within a tri-trophic food chain model involving species' mutual interference, characterized by Crowley–Martin functional response with strong Allee effect in prey species. First, the evaluation of the solutions' positivity and boundedness is conducted. Subsequently, the local stability of equilibrium points is analysed, and the Lyapunov function is employed to assess the global stability of interior equilibrium. We have also established adequate criteria for detecting local bifurcations. Sotomayor's theorem infers the presence of saddle–node and transcritical bifurcations. Utilizing the centre manifold theory and the Hopf bifurcation theorem, the emergence and stability of Hopf bifurcation are investigated. Following this, numerical simulations are performed so as to validate the theoretical findings and analyse the impacts of Allee effect in greater details. The analysis reveals that the system undergoes a range of local bifurcations in co-dimension one, including saddle–node, subcritical and supercritical Hopf bifurcations. Furthermore, the existence of global dynamics can be observed by the appearance of Generalized-Hopf bifurcation in the co-dimension two bifurcation diagram. The findings suggest that strong Allee effect could trigger instability and induce a bi-stability phenomenon in the system's dynamical behaviours. • A tri-trophic food chain model with a strong Allee effect is considered. • The occurrence of transcritical and saddle–node bifurcations is derived using Sotomayor's theorem. • The analysis of intricate dynamical features is conducted by means of co-dimension one and two bifurcations. • The model exhibits diverse behaviours and bi-stability phenomena at various Allee thresholds. • Prey with strong Allee effect have a higher chance of survival. [ABSTRACT FROM AUTHOR]

Highlights • The analysis of multiple spatial limit sets and chaos existence in MIMO cascade nonlinear systems consisting of large number of cascades (subsystems) using theorems is done in this paper. • It is shown that based on bifurcation diagrams of these systems the appearance of multiple spatial limit sets and chaos can be analyzed, also. • It should be noticed that in the case of MIMO system with large number of cascades monitoring dynamics of the whole system, using bifurcation diagram, is based on monitoring of all outputs of the last cascade x (k + 1) = [ x 1 (k + 1) , ... , x n (k + 1) ] as a function of control parameter l n. • Bifurcation diagram simulated in this way completelly shows the dynamics of the whole system. This is confirmed comparing segments of bifurcation diagram with phase portraits. Abstract The appearance of multiple spatial limit sets and chaos in MIMO cascade nonlinear systems is analyzed in this paper. The necessary and sufficient conditions for the existence of stable multiple spatial limit sets and the rules for the existence of chaos are given, too. The validity of these conditions is confirmed with bifurcation diagrams and spatial phase portraits of MIMO2 and MIMO4 cascade nonlinear systems. [ABSTRACT FROM AUTHOR]

Highlights • Turing instability condition for a Gierer–Meinhardt system of discrete time and space form are obtained. • Coupled map lattice is applied to study the spatiotemporal dynamics. • Hopf, flip bifurcation to chaos, together with Turing bifurcation are coupled to account for the complex patterns. • Striking patterns such as circle, spiral, mosaic and chaos are shown by numerical simulation. Abstract This paper is concerned with the spatiotemporal behaviors of a Gierer–Meinhardt system in discrete time and space form. Through the linear stability analysis, the parametric conditions are gained to ensure the stability of the homogeneous steady state of the system. Based on the bifurcation theory, as well as center manifold theorem, we derive the critical parameter values of the flip, Neimark–Sacker and Turing bifurcation respectively. Besides, the specific parameter expression to form patterns are also determined. In order to identify chaos among regular behaviors, we calculate the Maximum Lyapunov exponents. The results obtained in this paper are illustrated by numerical simulations. From the simulations, we can see some complex dynamics, such as period doubling cascade, invariant cycles, periodic windows, chaotic behaviors, and some striking Turing patterns, e.g. circle, mosaic, spiral, spatiotemporal chaotic patterns and so on, which can be produced by flip-Turing instability, Neimark–Sacker–Turing instability and chaos. [ABSTRACT FROM AUTHOR]

Persistence of solitary wave solutions of the regularized long wave equation with small perturbations are investigated by the geometric singular perturbation theory and bifurcation theory. Two different kinds of the perturbations are considered in this paper: one is the Kuramoto–Sivashinsky perturbation, the other is the Marangoni effects. Indeed, the solitary wave persists under small perturbations. Furthermore, the different perturbations do affect the proper wave speed c ensuring the persistence of the solitary waves. Finally, numerical simulations are utilized to confirm the theoretical results. [ABSTRACT FROM AUTHOR]

Abstract: Several recent contributions formalize and analyze binary choices games with externalities as those described by Schelling. Nevertheless, in the real world choices are not always binary, and players have often to decide among more than two alternatives. These kinds of interactions are examined in game theory where, starting from the well known rock-paper-scissor game, several other kinds of strategic interactions involving more than two choices are examined. In this paper we investigate how the dynamics evolve introducing one more option in binary choice games with externalities. The dynamics we obtain are always in a stable regime, that is, the structurally stable dynamics are only attracting cycles, but of any possible positive integer as period. We show that, depending on the structure of the game, the dynamics can be quite different from those existing when considering binary choices. The bifurcation structure, due to border collisions, is explained, showing the existence of so-called big-bang bifurcation points. [Copyright &y& Elsevier]

This paper demonstrates the existence of Feigenbaum's constants in reverse bifurcation for fractional-order Rössler system. First, the numerical algorithm of fractional-order Rössler system is presented. Then, the definition of Feigenbaum's constants in reverse bifurcation is provided. Third, in order to observe the effect of fractional-order to Feigenbaum's constants in reverse bifurcation, a series of bifurcation diagrams are computed. The Feigenbaum's constants in reverse bifurcation are measured and the error percentage in fractional-order Rössler system is presented. The simulation results show that Feigenbaum's constants exist in reverse bifurcation for fractional-order Rössler system. Especially, the Feigenbaum's constants still exist in the periodic windows. A summary on previous others’ works about Feigenbaum's constants is proposed. This paper draw a conclusion that the constants are universal in both period-doubling bifurcation and reverse bifurcation for both integer and fractional-order system. [ABSTRACT FROM AUTHOR]

In this paper, the dynamic behavior of a space- and time-discrete predator–prey system with Smith growth function is studied. Through the stability analysis, the parametric conditions are gained to ensure the stability of the homogeneous steady state of the system. Through the bifurcation theory, the expressions of the critical values for the occurrence of Neimark–Sacker bifurcation and flip bifurcation of the system are obtained, and the conditions for the occurrence of Turing bifurcation of the system are given. Finally, through numerical simulation, we can observe some complex dynamic behaviors, such as period-doubling cascade, invariant circles, periodic windows, chaotic dynamics and pattern formation. • This paper explores population diffusion. The diversity of pattern self-organization types of discrete predator–prey system is displayed, which provides a broad idea for the study of pattern dynamics of space- and time-discrete predator–prey system. • This paper focuses on the role of flip bifurcation and Neimark–Sacker bifurcation in discrete predator–prey system. Through the corresponding numerical simulation of bifurcation diagram, phase diagram and Lyapunov exponent diagram, the chaotic behavior caused by bifurcation and the dynamic characteristics on the chaotic path are shown. • The pattern dynamics of discrete predator–prey system is also studied in this paper. By constructing its space- and time-discrete coupled map lattice model, the conditions of Turing instability in the system are analyzed, and the self-organization formation process of Turing pattern is found through numerical simulation. [ABSTRACT FROM AUTHOR]

This paper discusses the extended simplest equation method for analyzing the behavior of a porous fin while taking into account the porous and convection parameters. This method helps in obtaining exact solutions and understanding the temperature distribution and heat transfer characteristics of the fin. Furthermore, the equation is transformed into a planar dynamical system using the Galilean transformation. Under dynamic and quasiperiodic conditions, the behavior of the equation is extensively discussed. The bifurcation of the planar system of dynamics described by the transformed equation is studied using bifurcation theory and phase portrait analysis. Additionally, a perturbed force is introduced to the dynamical system, and the RK4 method is employed to identify periodic or quasiperiodic patterns in the system. Sensitivity and multistability analysis are applied to the porous fin equation, considering different initial conditions to investigate its quasiperiodic and periodic behavior. The chaotic structure of the perturbed dynamical system using Lyapunov exponent analysis has also been discussed. Through a comparison between numerical solutions and graphical representations, the validity and applicability of the exact technique are demonstrated. The reported findings contribute novel insights into understanding the behavior of nonlinear equations encountered in mathematical physics. [ABSTRACT FROM AUTHOR]

The complex mixed-mode oscillation patterns are proposed and analyzed in a modified Rayleigh-Duffing oscillator based on the bifurcation theory in this paper. Four mixed-mode oscillations, namely "Homoclinic/Homoclinic-Homoclinic/Homoclinic" intermittent type, "fold/Homoclinic-Homoclinic/supHopf" intermittent type, "fold/Homoclinic-supHopf/supHopf" intermittent type and "fold/Homoclinic" type, are discussed in detail. Considering the low frequency excitations as slow-changing state variables, a modified autonomous system is obtained. The bifurcation characteristics of the fast subsystem are presented briefly by using the bifurcation theory. Then, we investigate the generation principle of the bifurcation delay phenomenon that performs a critical role in the production of two mixed-mode oscillations. This paper presents a fact that the dynamical behaviors are sensitive to the values of the system parameters and the parameters determine different forms of the repetitive spiking states that leads to different patterns of the mixed-mode oscillations. In addition, the theoretical analysis and numerical simulations are compared to illustrate the correctness of this paper. • A route to mixed-mode oscillations named "Hopf bifurcation delay" is proposed. • A modified autonomous system is obtained by considering the low frequency excitations as slow-varying state variables. • Two Hopf-bifurcation-delay-triggered mixed-mode oscillations and two pure bifurcation-structure-induced mixed-mode oscillations are investigated. • Dynamical evolutions among different bursting patterns are studied by the two-parameter bifurcation diagram. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this paper is to study the dynamics of a monopolistic firm in a continuous-time framework. The firm is assumed to be boundedly rational and to experience time delays in obtaining and implementing information on output. The dynamic adjustment process is based on the gradient of the expected profit. The paper is divided into three parts: we examine delay effects on dynamics caused by one-time delay and two-time delays in the first two parts. Global dynamics and analytical results on local dynamics are numerically confirmed in the third part. Four main results are demonstrated. First, the stability switch from stability to instability occurs only once in the case of a single delay. Second, the alternation of stability and instability can continue if two time delays are involved. Third, the occurence of Hopf bifurcation is analytically shown if stability is lost. Finally, in a bifurcation process, there are a period-doubling cascade to chaos and a period-halving cascade to the equilibrium point in the case of two time delays if the difference between the two delays is large. [Copyright &y& Elsevier]

• We provide an epidemic SIR model with long-range temporal memory governed by delay differential equations with fractional-order. • The existence of steady states and the asymptotic stability of the steady states are discussed. • The occurrence of Hopf bifurcation is captured when the time-delay passes through a critical value. • Theoretical results are validated numerically. In this paper, we provide an epidemic SIR model with long-range temporal memory. The model is governed by delay differential equations with fractional-order. We assume that the susceptible is obeying the logistic form in which the incidence term is of saturated form with the susceptible. Several theoretical results related to the existence of steady states and the asymptotic stability of the steady states are discussed. We use a suitable Lyapunov functional to formulate a new set of sufficient conditions that guarantee the global stability of the steady states. The occurrence of Hopf bifurcation is captured when the time-delay τ passes through a critical value τ *. Theoretical results are validated numerically by solving the governing system, using the modified Adams-Bashforth-Moulton predictor-corrector scheme. Our findings show that the combination of fractional-order derivative and time-delay in the model improves the dynamics and increases complexity of the model. In some cases, the phase portrait gets stretched as the order of the derivative is reduced. [ABSTRACT FROM AUTHOR]

• Dynamical behaviour of a Leslie–Gower model with Holling type-IV functional response and nonlinear age-selective prey harvesting has been studied. • Qualitative analysis, bifurcation theory, bionomic equilibrium, MSY and optimal harvesting policy has been analyzed. • The age-selective harvesting system under goes a Hopf bifurcation with respect to the maturation delay. • Conditions for the MSY and existence of bionomic equilibrium are analyzed and Pontryagin's maximum principle has been used to find the path of a singular control and Pontryagin's maximum principle has been used to find the path of a singular control. In this paper, we have studied the dynamical behaviour of a Leslie-Gower model with Holling type-IV functional response and nonlinear prey harvesting where target prey for harvesting are above a particular age which is called maturation delay. The model system has been studied using qualitative analysis, bifurcation theory, bionomic equilibrium, MSY and optimal harvesting policy. We explain that the interior equilibrium is delay dependent and locally asymptotically stable. The age-selective harvesting system under goes a Hopf-bifurcation with respect to the maturation delay. Conditions for the MSY and existence of bionomic equilibrium are analyzed and Pontryagin's maximum principle has been used to find the path of a singular control. Difficult analytical results are featured by numerical examples to better understand the system in a simple way. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we construct a duopoly model of technological innovation based on constant conjectural variation under the assumption of bounded rationality. The equilibrium points of constant conjectural variation and their local stability are investigated. By the theoretical proof, we prove that the model displays Li-Yorke chaos and distributional chaos in the ranges of the output adjusted coefficients by employing the snap-back repeller theory. The technological innovation is the main source of the core competitiveness of a firm, and technological content is an important factor of technological innovation. We find that the firms have the optimal technological contents while they could have the maximal profits in the two different situations, non-cooperative technological innovation and cooperative technological innovation. It's proved that the cooperation of technological innovation can increase the marginal technological content, and benefit to technological progress. Then Numerical simulations are used to illustrate the dynamic analysis of the model under the situations with different technological innovation and conjectural variation. When the output adjusted coefficient changes, a series of complex phenomena including bifurcation, chaos and strange attractor can be observed in our model. And when the technological content is larger, the chaos of the system finally appears. [ABSTRACT FROM AUTHOR]

Highlights • A novel memristive 6D hyperchaotic autonomous system with extreme multistability. • Hidden attractor under a line and a plan of equilibria. • Numerical evidence of transient chaos followed by periodic bursting oscillations, of intermittency and boosting behaviors. • PSpice simulations are introduced in order to validate the numerical results. Abstract This paper presents a 6D autonomous system, obtained by introducing a flux-controlled memristor model into an existing 5D hyperchaotic autonomous system. The dynamics of the novel system are investigated in terms of equilibrium points, bifurcation diagrams, Lyapunov exponent spectra, phase portraits, time series and attraction basins. Moreover, its circuit implementation is also proposed. The system is hyperchaotic under a line or a plan of equilibria. Other attractive dynamics observed are: hidden extreme multistability, transient chaos, bursting and offset boosting phenomenon. Interestingly, for a particular set of parameters, an unusual metastability showing transition from chaotic to periodic bursting dynamics is found. Dynamical systems capable of producing the above complexity are not common in the literature; thus, this novel memristive 6D hyperchaotic autonomous system deserves particular attention. PSpice based simulations are in good agreement with numerical computations. To the best of our knowledge, this system is the first with higher order presenting all those phenomena. [ABSTRACT FROM AUTHOR]

Highlights • Three fractional-order discrete chaotic maps are proposed. • Important dynamics of three maps are investigated. • A stabilizing strategy is introduced for the proposed maps. • A combined synchronization scheme is presented. Abstract In this paper, we propose three systems, namely the fractional Lozi map, the fractional Lorenz map, and the fractional flow map. We study some of the important dynamics of these maps including the bifurcation graphs. In addition, we propose control laws aimed at stabilizing and synchronizing a combination of these three maps. The convergence of the stabilized states and the synchronization errors is established by means of the linearization method. Numerical simulations are also presented to confirm the main findings of the study. [ABSTRACT FROM AUTHOR]

Highlights • NLPSO is a non-Lyapunov bifurcation parameter detection strategy. • Problems in detecting saddle-node bifurcation parameters by NLPSO were clarified. • The problems were solved by imposing a simple condition on the objective function. • The extended NLPSO accurately detected saddle-node bifurcation parameters. Abstract Nested-layer particle swarm optimization (NLPSO) detects bifurcation parameters in discrete-time dynamical systems. Previous studies have proven the effectiveness of NLPSO for period-doubling bifurcations, but not for other bifurcation phenomena. This paper demonstrates that NLPSO can effectively detect saddle-node bifurcations. Problems in detecting saddle-node bifurcation parameters by conventional NLPSO are clarified, and are solved by imposing a simple condition on the NLPSO objective function. Under this conditional objective function, the NLPSO accurately detected both saddle-node and period-doubling bifurcation parameters regardless of their stability, without requiring careful initialization, exact calculations or Lyapunov exponents. [ABSTRACT FROM AUTHOR]

Highlights • Influence of group defense and prey harvesting in predator-prey model is discussed. • Harvesting rate plays a crucial rule for coexistence of both the species. • Sufficient conditions for the existence and stability of equilibria are established. • Occurrence of several bifurcations is proved. • Numerical simulation shows chaotic and periodic oscillations of the system. Abstract We discuss the stability and bifurcation analysis of predator-prey model in the presence of group defense and non-linear harvesting in prey. Mathematically, we analyze the dynamics of the system such as boundedness of the solutions, existence and stability conditions of the equilibrium points. The model undergoes saddle-node, transcritical and Hopf-Andronov bifurcations. The direction of Hopf bifurcation by calculating the first Lyapunov number is examined. The effects of prey harvesting rate and death rate of predator on the model by considering them as bifurcation parameters are analyzed. In this paper, we dedicate ourselves to the investigation of the complex dynamics of the model to maintain the coexistence of the species which is important for ecological balance in the real environment. Several numerical simulations are performed to substantiate our analytical findings. [ABSTRACT FROM AUTHOR]

Abstract The stability and bifurcation behavior of a kind of active magnetic bearing rotor are investigated in this paper. The analysis is carried out both analytically and numerically. It is found that a Hopf bifurcation occurs in the system by using center manifold and normal form. Numerical simulation is conducted to validate the theoretical predictions. More precisely, the dynamic characteristics of this system in two-dimensional parameter space are analyzed, the phase diagrams assist us to identify multi-attractor coexisting that makes the dynamical behaviors of the system become more enrich and complex. These results we represent can be useful in designing and selection of suitable operating parameters. As a result, the system can avoid the undesirable behavior. [ABSTRACT FROM AUTHOR]

Highlights • A network with wireless access links with a delay differential equation (DDE) model and input delay is considered. • Integral sliding mode control is assumed as the nonlinear robust active queue management in the network. • Hopf bifurcation analysis is investigated with the transmission delay considered as the Hopf bifurcation parameter. • The direction and the stability of the bifurcation periodic solutions are determined. • Simulation results are provided to illustrate the system behavior with different parameters. Abstract Transmission control protocol (TCP), which is usually implemented in the transport layer of a communication network, can detect the congestion after its occurrence. But congestion control can be more complicated in networks with wireless access links due to time-varying fading and packet error rate (PER). Thus, it is essential to use robust active queue management (RAQM) to prevent congestion with certain tolerance against serious disturbance of the wireless environment. As the stability of a TCP/RAQM is tremendously related to the transmission delay, this paper focuses on Hopf bifurcation analysis of a network governed by nonlinear delayed differential equations and an integral sliding mode control as a nonlinear RAQM. The transmission delay is assumed as the bifurcation parameter. It is shown that if the delay passes through a critical value, the closed loop system would not remain stable and the Hopf bifurcation occurs. Moreover, based on the normal form theory and the center manifold theorem, the direction and the stability of the bifurcation periodic solutions are determined. Finally, simulation results are given to confirm the analytical achievements and to show the effectiveness of the procedure compared to some recent protocols. [ABSTRACT FROM AUTHOR]

Highlights • A novel hyperchaotic oscillator and its mathematical model. • Numerical evidence metastable chaos and bursting oscillations. • Coexistence of two disconnected attractors. • Experimental evidence of the hyperchaotic oscillations in the NHO. Abstract This paper is investigating the hyperchaotic dynamics of a novel hyperchaotic oscillator (made of only three electronics components namely a transformer, a capacitor and a junction field effect transistor (JFET)) obtained by modifying the simple chaotic circuit proposed by Tchitnga et al. (doi:10.1016/j.chaos.2011.12.017) and published within this journal. The various laboratory tests on the novel three components oscillator help to confirm that it operates at high frequencies. Henceforth, justified the choice of Giacolleto model of JFET. Hyperchaos is analysed using well known nonlinear dynamic tools including bifurcation diagrams, Lyapunov exponent spectrum, phase portraits and Poincaré sections. Likewise, the high frequency is confirmed through the frequency spectrum simulated with PSpice. The systems also present the striking phenomena of hysteretic dynamics (bistability) and transient chaos as well as bursting oscillations over a wide range of its control parameter region. The measurements from experimental investigations are in accordance with the obtained numerical results. [ABSTRACT FROM AUTHOR]

Abstract: Period-doubling bifurcation and its route to chaos have been thoroughly investigated in voltage-mode and current-mode controlled DC motor drives under simple proportional control. In this paper, the phenomena of Hopf bifurcation and chaos from torus breakdown in a voltage-mode controlled DC drive system is reported. It has been shown that Hopf bifurcation may occur when the DC drive system adopts a more practical proportional-integral control. The phenomena of period-adding and phase-locking are also observed after the Hopf bifurcation. Furthermore, it is shown that the stable torus can breakdown and chaos emerges afterwards. The work presented in this paper provides more complete information about the dynamical behaviors of DC drive systems. [Copyright &y& Elsevier]

Abstract: Starting from the delay Liénard and van der Pol equations with time delay, this paper represents an attempt to give an introductory presentation of dynamics for a class of nonlinear systems with time delay and emphasizes the recent development on this field in china. It is clearly seen that the time delay occurred in systems can lead to the rich dynamical behaviors such as death island, Hopf bifurcation, double Hopf bifurcation, period-doubling bifurcation, phase locked (periodic) and phase shifting solutions, co-existing motions, quasi-periodic motion and even chaos. In the quantitative and qualitative treatment of the analytical method, a new method, called perturbation-incremental scheme (PIS), is introduced by two steps, namely perturbation and increment for continuation to the critical value at a simple Hopf bifurcation. This paper shows that time delay may be used as a simple but efficient “switch” to control motions of a system: either from order to complex motions or from complex to order motions for different applications. As well as the PIS can bypass and avoid the tedious calculation of the center manifold reduction (CMR) and normal form. [Copyright &y& Elsevier]

Abstract: The paper describes an experimental study of the bifurcation behaviour of a modular peak current-mode controlled DC–DC boost converter. The parallel-input/parallel-output converter comprises two identical boost circuits and operates in the continuous-current conduction mode. A comparison is made between the results obtained from an experimental converter with those obtained from bifurcation diagrams generated from previous work and waveforms from a new MATLAB/SIMULINK simulation presented in this paper. Another comparison is made between the modular converter diagrams with those of the single boost converter. [Copyright &y& Elsevier]

Abstract: In this paper, complex dynamical behavior of a class of centrifugal flywheel governor system is studied. These systems have a rich variety of nonlinear behavior, which are investigated here by numerically integrating the Lagrangian equations of motion. A tiny change in parameters can lead to an enormous difference in the long-term behavior of the system. Bubbles of periodic orbits may also occur within the bifurcation sequence. Hyperchaotic behavior is also observed in cases where two of the Lyapunov exponents are positive, one is zero, and one is negative. The routes to chaos are analyzed using Poincaré maps, which are found to be more complicated than those of nonlinear rotational machines. Periodic and chaotic motions can be clearly distinguished by all of the analytical tools applied here, namely Poincaré sections, bifurcation diagrams, Lyapunov exponents, and Lyapunov dimensions. This paper proposes a parametric open-plus-closed-loop approach to controlling chaos, which is capable of switching from chaotic motion to any desired periodic orbit. The theoretical work and numerical simulations of this paper can be extended to other systems. Finally, the results of this paper are of practical utility to designers of rotational machines. [Copyright &y& Elsevier]

Abstract: The paper considers a Bertrand model with bounded rational. A duopoly game is modelled by two nonlinear difference equations. By using the theory of bifurcations of dynamical systems, the existence and stability for the equilibria of this system are obtained. Numerical simulations used to show bifurcations diagrams, phase portraits for various parameters and sensitive dependence on initial conditions. We observe that an increase of the speed of adjustment of bounded rational player may change the stability of Nash equilibrium point and cause bifurcation and chaos to occur. The analysis and results in this paper are interesting in mathematics and economics. [Copyright &y& Elsevier]

Abstract: This paper investigates the nonlinear response and bifurcation of rotor with Squeezed Film Damper (SFD) supported on elastic foundation. The motion equations are derived. To analyze the bifurcation of nonlinear response of SFD rotor, the Floquet Multipliers is obtained by solving the perturbation equations with numerical method. For computing Floquet Multipliers, a novel method is presented in this paper, which can begin integration at the stable solution. Simulation results are given in two figures. One figure, which consists of eight subfigures, gives the effect of rotating speed on the response of SFD damper supported on elastic foundation: with increasing rotating speed, the nonlinear response evolves from quasi-period to period, then jumps between different periods, and finally returns to quasi-period; the corresponding bifurcations are saddle-node bifurcation and secondary Hopf bifurcation. The second figure, which consists of six subfigures, shows that: the support stiffness has large influence on the response of bearings and film force in SFD; large support stiffness can lead to oil whirl in SFD. [Copyright &y& Elsevier]

Abstract: In this paper, a Z 3-equivariant quartic planar vector field is studied. The Hopf bifurcation method and polycycle bifurcation method are combined to study the limit cycles bifurcated from the polycycle with three hyperbolic saddle points. It is found that this special quartic planar polynomial system has at least three large limit cycles which surround 13 singular points. By applying the double homoclinic loops bifurcation method and Poincaré–Bendixson theorem, we conclude that 16 limit cycles with two different configurations exist in this special planar polynomial system. The results acquired in this paper are useful to the study of the second part of 16th Hilbert Problem. [Copyright &y& Elsevier]

Abstract: For a more precise description of rotor–bearing system, a nonlinear supported model is proposed in this paper, where a linear damping, a nonlinear elastic restoring force and a turbulent lubricant flow model are assumed. The dynamics of the rotor center and bearing center are studied. The spatial displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The dynamic equations are solved using the Runge–Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, Poincaré maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The numerical results show that the stability of the system varies with the non-dimensional speed ratios. Specifically, it is found that the dynamic behaviors of the system include 2T-periodic, quasi-periodic and chaotic motions. The modeling results thus obtained by using the method proposed in this paper can be employed to predict the stability of the rotor–bearing system and the undesirable behavior of the rotor and bearing center can be avoided. [Copyright &y& Elsevier]

Abstract: In this paper we study some global bifurcations arising in the Puu’s oligopoly model when we assume that the producers do not adjust to the best reply but use an adaptive process to obtain at each step the new production. Such bifurcations cause the appearance of a pair of closed invariant curves, one attracting and one repelling, this latter being involved in the subcritical Neimark bifurcation of the Cournot equilibrium point. The aim of the paper is to highlight the relationship between the global bifurcations causing the appearance/disappearance of two invariant closed curves and the homoclinic connections of some saddle cycle, already conjectured in [Agliari A, Gardini L, Puu T. Some global bifurcations related to the appearance of closed invariant curves. Comput Math Simul 2005;68:201–19]. We refine the results obtained in such a paper, showing that the appearance/disappearance of closed invariant curves is not necessarily related to the existence of an attracting cycle. The characterization of the periodicity tongues (i.e. a region of the parameter space in which an attracting cycle exists) associated with a subcritical Neimark bifurcation is also discussed. [Copyright &y& Elsevier]

Abstract: In this paper, we investigate the dynamical behaviors of neural excitable system without periodic external current (proposed by Chialvo [Generic excitable dynamics on a two-dimensional map. Chaos, Solitons & Fractals 1995;5(3–4):461–79] and with periodic external current as system’s parameters vary. The existence and stability of three fixed points, bifurcation of fixed points, the conditions of existences of fold bifurcation, flip bifurcation and Hopf bifurcation are derived by using bifurcation theory and center manifold theorem. The chaotic existence in the sense of Marotto’s definition of chaos is proved. We then give the numerical simulated results (using bifurcation diagrams, computations of Maximum Lyapunov exponent and phase portraits), which not only show the consistence with the analytic results but also display new and interesting dynamical behaviors, including the complete period-doubling and inverse period-doubling bifurcation, symmetry period-doubling bifurcations of period-3 orbit, simultaneous occurrence of two different routes (invariant cycle and period-doubling bifurcations) to chaos for a given bifurcation parameter, sudden disappearance of chaos at one critical point, a great abundance of period windows (period 2 to 10, 12, 19, 20 orbits, and so on) in transient chaotic regions with interior crises, strange chaotic attractors and strange non-chaotic attractor. In particular, the parameter k plays a important role in the system, which can leave the chaotic behavior or the quasi-periodic behavior to period-1 orbit as k varies, and it can be considered as an control strategy of chaos by adjusting the parameter k. Combining the existing results in [Generic excitable dynamics on a two-dimensional map. Chaos, Solitons & Fractals 1995;5(3–4):461–79] with the new results reported in this paper, a more complete description of the system is now obtained. [Copyright &y& Elsevier]

Abstract: A planar pendulum is considered which is parametrically excited by a periodic vertical force. The amplitude and frequency of the excitation are used as control parameters. The downward, hanging and the upward, inverted positions correspond to equilibrium positions if we only consider the variation in angle measured from the downward position. For moderate levels of forcing, there are zones that exist in the space of control parameters, where the downward hanging position is unstable and initial conditions that are close to the hanging position lead to steady state oscillations of period-2. To review this situation, this paper describes the development of these oscillations as the amplitude of forcing is varied. In the largest zone, a symmetry-breaking occurs which brings about a pair of asymmetric oscillations. This break in symmetry of the period-2 solution can lead to either an increase or decrease in the amplitude of the forthcoming swing and reference to the experimental significance of this angle change is noted in this paper. Typically, further increases of the parameter produce a cascade of period doubling bifurcations, before most oscillating solutions eventually lose their stability so that the system must experience a rotation. As a result, symmetry-breaking becomes an effective precursor to escape from the local potential well around the hanging position. Here we compare this behaviour with that in other resonance zones. The change of geometric structure when the symmetry-breaking bifurcation occurs is examined and graphically represented as a ‘pinched’ cylinder-like shape, compared with the Möbius strip that has been associated with the period-doubling bifurcation. The paper also refers to practical problems, where the introduction of nonlinearity means that potentially all frequencies below the main zone of the control space lead to dangerous effects and in some scenarios disastrous outcomes. [Copyright &y& Elsevier]

This paper presents an approach to characterize the conditions that can possibly lead to chaotic motion for a simply supported large deflection circular plate of thermo-mechanical coupling by utilizing the criterion of the maximum Lyapunov exponent. The governing partial differential equation of the simply supported large deflection circular plate of thermo-mechanical coupling is first derived and simplified to a set of three ordinary differential equations by the Galerkin method. Several different features including time history, Power spectra, phase plot, Poincare map and bifurcation diagram are then numerically computed. These features are used to characterize the dynamic behavior of the plate subjected various geometric and excitation conditions. Numerical examples are presented to verify the validity of the conditions that lead to chaotic motion and the effectiveness of the proposed modeling approach. The modeling results of numerical simulation indicate that the chaotic motion may occurs in the lateral loads &fmacr;=2.5, η1=1.1, β=0.5, δ=0.01 and #x03B5;∞=0.0007. As the thermo-elastic damping is great than a critical value, the dynamic motion of the thermal-couple plate is periodic. As the thickness parameter β of the concave circular plate is great than a critical value, the motion of the plate is periodic. The modeling result thus obtained by using the method proposed in this paper can be employed to predict the instability induced by the dynamics of the thermo-mechanical coupling circular plate in large deflection. [Copyright &y& Elsevier]

This paper characterizes the complex dynamics of the permanent-magnet synchronous motor (PMSM) model with a non-smooth-air-gap, extending the work on the smooth case studied elsewhere. The stability, the number of equilibrium points, and the pitchfork and Hopf bifurcations are analyzed by using bifurcation theory and the center manifold theorem. Numerical simulations not only confirm the theoretical analysis results but also show some more new results including the period-doubling bifurcation, cyclic fold bifurcation, single-scroll and double-scroll chaotic attractors, ribbon-chaotic attractor, as well as intermittent chaos that are different from those reported in the literature before. Moreover, analytical expressions of an approximate stability boundary are given, by computing the local quadratic approximation of the two-dimensional stable manifold at an order-2 saddle point. Combining the existing results with the new results reported in this paper, a fairly complete description of the complex dynamics of the PMSM model is now obtained. [Copyright &y& Elsevier]

This paper discussed the interference between external electric exposure and biological objects. Based on results of space-time characteristics of trans-membrane voltage, the variation of cell trans-membrane voltage exposed to extremely low frequency (ELF) electrical field was analyzed; the traditional Hodgkin–Huxley model was modified by importing new parameter denoting external electrical fields, and the bifurcation caused by new parameter war found. This paper employed the algebra criterion in high dimension equations to perform the analysis of single parameter dynamical bifurcation. The results were biological significant and suggested that the aberration of dynamics in bio-systems may be accounted for diseases caused by electric exposure. [Copyright &y& Elsevier]

We consider a 2D piecewise-linear discontinuous map defined on three partitions that drives the dynamics of a stock market model. This model is a modification of our previous model associated with a map defined on two partitions. In the present paper, we add more realistic assumptions with respect to the behavior of sentiment traders. Sentiment traders optimistically buy (pessimistically sell) a certain amount of stocks when the stock market is sufficiently rising (falling); otherwise they are inactive. As a result, the action of the price adjustment is represented by a map defined by three different functions, on three different partitions. This leads, in particular, to families of attracting cycles which are new with respect to those associated with a map defined on two partitions. We illustrate how to detect analytically the periodicity regions of these cycles considering the simplest cases of rotation number 1 / n , n ≥ 3 , and obtaining in explicit form the bifurcation boundaries of the corresponding regions. We show that in the parameter space, these regions form two different overlapping period-adding structures that issue from the center bifurcation line. In particular, each point of this line, associated with a rational rotation number, is an issue point for two different periodicity regions related to attracting cycles with the same rotation number but with different symbolic sequences. Since these regions overlap with each other and with the domain of a locally stable fixed point, a characteristic feature of the map is multistability, which we describe by considering the corresponding basins of attraction. Our results contribute to the development of the bifurcation theory for discontinuous maps, as well as to the understanding of the excessively volatile boom-bust nature of stock markets. • A 2D discontinuous map on three partitions related to a stock market model is considered. • We detect analytically the periodicity regions of attracting cycles with rotation number 1/n, n > 2. • They form two overlapping period-adding structures issuing from the center bifurcation line. • We describe multistability by considering the corresponding basins of attraction. • We contribute to the theory of non-smooth maps and the understanding of stock market volatility. [ABSTRACT FROM AUTHOR]

Bifurcation theory is the usual analytic approach to study the parameter space of a dynamical system. Despite the great power of prediction of these techniques, fundamental limitations appear during the study of a given problem. Nonlinear dynamical systems often hide their secrets and the ultimate resource is the numerical simulation of the equations. This paper presents a method to explore bifurcations by using the basin entropy. This measure of the unpredictability can detect transformations of phase space structures as a parameter evolves. We present several examples where the bifurcations in the parameter space have a quantitative effect on the basin entropy. Moreover, some transformations, such as the basin boundary metamorphoses, can be identified with the basin entropy but are not reflected in the bifurcation diagram. The correct interpretation of the basin entropy plotted as a parameter extends the numerical exploration of dynamical systems. • Exploration of the bifurcations using the basin entropy. • Detection of the transformations of the phase space. • Basin boundary metamorphoses are identified with the basin entropy. [ABSTRACT FROM AUTHOR]

In this paper, the modified Kadomtsev Petviashvili (mKP) equation is derived by considering the dynamics of the dust-acoustic waves (DAWs) with kappa-distributed hot and cold ions and Boltzmannian electrons. The reductive perturbation technique is applied for deriving mKP. The bifurcation theory of the planar dynamical system is used to obtain the phase portrait of the DAWs in the framework of mKP equation. The formation of dust-acoustic solitary waves (DASWs) is analyzed for different plasma parameters in the Saturn's magnetosphere. In the current plasma model, the external periodic force is introduced to study the quasiperiodic and chaotic behavior of the DAWs. It is noted that periodic initial conditions lead to the emergence of many outlandish features in the system by comparison with the solitary initial conditions. The frequency of the external periodic force ω plays an important role in the transition from quasiperiodic to chaotic behavior. Moreover, the strength of the external periodic force, the value of the nonlinear coefficient of the mKP equation, and the nonlinear acoustic speed are also found to have a significant effect on the chaotic behavior of the system. • Dynamical system and phase portrait analysis of the mKP Equation. • The bifurcation theory is applied to obtain the phase portrait of the dust-acoustic waves (DAWs). • Dust-acoustic solitons are investigated for Saturn's magnetosphere plasma parameters. • External periodic force (EPF) is introduced for studying the chaotic behavior of DAWs. • The EPF frequency has a great role in the transition from quasiperiodic to chaotic behavior. [ABSTRACT FROM AUTHOR]

Highlights ● Singular systems theory together with fractional calculus is utilized to model the logistic growth, and a fractional-order singular (FOS) logistic map is introduced. ● An effective necessary and sufficient stability criterion has been given for arbitrary FOS discrete-based systems. ● Using presented approach of calculating Lyapunov exponents (LEs) and also bifurcation diagrams, existence of (inverse) period-doubling route to chaos has been explored. ● Besides the role of growth rate parameter, the impact of fractional order and economic interest parameters on the chaotic zones has been demonstrated. Abstract Recently fractional calculus started to gain much importance due to its applications to the mathematical modeling of real phenomena with memory effect. Besides, singular modeling, which has been accompanied by exhibiting more complicated dynamics rather than standard models, can reveal the instability mechanism of wide-range of physical systems. Utilizing these two applicable techniques of modeling, a generalization of the logistic growth model, which takes into account the effects of memory and economic interest, is suggested in this paper. Besides mathematical analysis and extracting new results on the equilibrium points and local stability studies of discrete-time commensurate fractional-order singular (FOS) state space systems, some basic dynamical properties and qualitative analysis of the new chaotic FOS logistic map are studied, either numerically or analytically, to explore the impacts of real order and economic interest on the presented system in biological contexts. [ABSTRACT FROM AUTHOR]

Highlights • A three dimensional nonlinear oscillator with an unstable equilibrium is discussed. • The oscillator exhibits different dynamics such as periodic orbit, torus, and chaos. • The system is multistable with different symmetric coexisting attractors. • Entropy analysis of the system shows variations of its complexity. • A designed circuit of the chaotic oscillator is introduced. Abstract In this paper, a three dimensional chaotic system with special properties is investigated. The system has an unstable equilibrium and a self-excited chaotic attractor in some parameters. Bifurcation analysis of the system shows different dynamics such as periodic orbit, torus and chaos. Also the system has multistability with some symmetric coexisting attractors. Entropy analysis of the system indicates variations in the complexity of the system's dynamic. A circuit design is introduced to clarify the system's feasibility practically. [ABSTRACT FROM AUTHOR]

Highlights • Hindmarsh–Rose neuron model is analyzed analytically and numerically • Atangana–Baleanu fractional derivative in Caputo sense is used in the modeling • The system reveals existence of equilibria whose some are unstable • It also reveals a system with initially regular bursts that evolve into chaos • Repeated bursts happen to occur more rapidly in time as derivative order decreases Abstract Recent discussions on the non validity of index law in fractional calculus have shown the amazing filtering feature of Mittag–Leffler function foreseing Atangana–Baleanu derivative as one of reliable mathematical tools for describing some complex world problems, like problems of neuronal activities. In this paper, neuronal dynamics described by a three dimensional model of Hindmarsh–Rose nerve cells with external current are analyzed analytically and numerically. We make use of the Atangana–Baleanu fractional derivative in Caputo sense (ABC derivative) and asses its impact on the dynamic, especially the role played by its derivative order in combination with another control parameter, the intensity of the applied external current. Our analysis proves existence of equilibria whose some are unstable of type saddle point, paving the ways for possible bifurcations in the process. Numerical approximations of solutions reveal a system with initially regular bursts that evolve into period-adding chaotic bifurcations as the control parameters change, with precisely the Atangana–Baleanu fractional derivative's order decreasing from 1 down to 0.5. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we first investigate global phase portraits of a class of quadratic reversible systems with a center of genus one, and obtain six possible global phase portraits. We then perturb the phase portrait with a non-Morsean point, by using nth order polynomials, n = 1 , 2 , ... , 7. For the perturbed systems, we study the limit cycle bifurcation problem, obtaining some new results. [ABSTRACT FROM AUTHOR]

Highlights • Accounting for the flow reversal time scale substantially affects the model's period. • Neglecting the flow reversal time scale is legitimate in some range of parameters. • The model exhibits sliding motion before going through bifurcation. • The model exhibits a non-conventional Hopf bifurcation. • The saline oscillator can be utilized to measure density of liquids. • The measuring principle relies on density-dependence of the midpoint of oscillation. Abstract The saline oscillator has been modeled by several Filippov systems in the literature. In this paper, we examine the effects of the novel feature of the recently introduced model, onto its output. We then investigate the bifurcation process of the saline oscillator's model in the framework of Filippov theory. We find that the recently introduced modification substantially affects the period of the output of the model in case the ratio a / b of radii of the orifice and the inner container is considerable. The theoretical analysis predicts that the model goes through a non-conventional Hopf bifurcation which could appear as result of a sliding motion on the switching boundary. In case a / b is insignificant, a relationship between the midpoint of oscillation, the system geometrical parameters and the liquids densities is analytically derived. To validate this formula, we compute the dependencies on system parameters of the midpoint of oscillation by numerically solving the model. Then, we compare these dependencies of the midpoint of oscillation with those directly obtained from the analytical formula. We then show, from this relation, that another practical application of the saline oscillator is the measurement of the density of a liquid. Finally, we describe the method of measurement and propose a sketch for a density meter, based on saline oscillator, which is suitable for samples of small volume and does not need calibration procedure. [ABSTRACT FROM AUTHOR]

This paper addresses the issues of the control of chaotic motions in a mixed Rayleigh-Liénard oscillator by amplitude modulated excitation. The Melnikov method is used to analytically determine the domains boundaries where horseshoes chaos appears. The basin of attraction has been drawn to confirm the horseshoes chaos appearance domain. Routes to chaos are investigated through bifurcations structures, Lyapunov exponent, phase portraits and Poincaré section. The effects of control force on chaotic motions are strongly analyzed and the control efficiency is found where the cases of g = 0 (unmodulated case), g  ≠ 0 with Ω = ω and Ω ω ≠ p q where p and q are simple positive integers are considered. Results of analytical investigations are validated and complemented by numerical simulations. [ABSTRACT FROM AUTHOR]

In this paper, we study the bifurcation of limit cycles in two special near-Hamiltonian polynomial planer systems which their corresponding Hamiltonian systems have a heteroclinic loop connecting a hyperbolic saddle and a cusp of order two. In these systems, we will compute the asymptotic expansions of corresponding first order Melnikov functions near the loop and the center to analyze the number of limit cycles. Moreover, in the first system, by using the Chebychev criterion, we study the Poincaré bifurcation. [ABSTRACT FROM AUTHOR]

The Duffing equation describes a periodically forced oscillator model with a nonlinear elasticity. In its circuitry, a saturable-iron core often exhibits a hysteresis, however, a few studies about the Duffing equation has discussed the effects of the hysteresis because of difficulties in their mathematical treatment. In this paper, we investigate a forced planer system obtained by replacing a cubic term in the Duffing equation with a hysteresis function. For simplicity, we approximate the hysteresis to a piecewise linear function. Since the solutions are expressed by combinations of some dynamical systems and switching conditions, a finite-state machine is derived from the hybrid system approach, and then bifurcation theory can be applied to it. We topologically classify periodic solutions and compute local and grazing bifurcation sets accurately. In comparison with the Duffing equation, we discuss the effects caused by the hysteresis, such as the devil’s staircase in resonant solutions. [ABSTRACT FROM AUTHOR]

In this paper, the dynamical analysis of a delayed reaction-diffusion virus infection model with logistic growth and chemotaxis for the uninfected target cells and humoral immune impairment is studied. By analyzing corresponding characteristic equations, the local stability of the infection-free equilibrium is established. The stability properties and Turing instability of the antibody-free equilibrium and antibody-present infection equilibrium have been extensively discussed. The existence of Hopf bifurcation with antibody response delay as a bifurcation parameter at the antibody-present infection equilibrium is established. The numerical simulations are carried out in order to illustrate the dynamical behavior of the model. [ABSTRACT FROM AUTHOR]

This paper proposes the definition of stretched exponential stability. First, a non-Debye decay is found in the nonlinear Hausdorff dynamical systems by using the Lyapunov direct method, which leads to the stretched exponential stability. It is worthy of noting that the classical exponential stability is a special case of the proposed stretched exponential stability, when the stretched parameter is in its limiting case equal to 1. Therefore the stretched exponential has more flexibility and applicability to the real-world problems than the classical exponential stability. Second, a fractal comparison principle is applied to obtain stability criteria for the proposed systems. Examples are presented to illustrate the applicability of the proposed concept. [ABSTRACT FROM AUTHOR]

This paper presents a novel third-order autonomous memristive diode bridge-based oscillator with fast-slow effect. Based on the modeling of the presented memristive oscillator, stability of the equilibrium point is analyzed by using the eigenvalues of the characteristic polynomial, and then symmetric periodic bursting behavior is revealed through bifurcation diagrams, phase plane plots, time sequences, and 0–1 test. Furthermore, bifurcation mechanism of the symmetric periodic bursting behavior is explored by constructing the fold and Hopf bifurcation sets of the fast-scale subsystem with the variations of the system parameter and slow-scale variable. Consequently, the presented memristive oscillator is always unstable and exhibits complex dynamical behavior of symmetric periodic bursting oscillations with a symmetric fold/Hopf cycle-cycle burster. In addition, experimental measurements are performed by hardware circuit to confirm the numerical simulations. [ABSTRACT FROM AUTHOR]

Chaotic attractors in the classical Lorenz system have long been known as self-excited attractors. This paper, for the first time, reveals a novel hidden chaotic attractor in the classical Lorenz system. Either a self-excited or a hidden chaotic attractor is now possible in the classical Lorenz system depending on values of both system parameters and initial conditions. A systematically exhaustive computer search is employed to directly search for the hidden chaotic attractor with elegant values of both system parameters and initial conditions. Time series of trajectories, Lyapunov exponents, and bifurcations of the hidden chaotic attractor are reported. Basins of attraction of individual equilibria are depicted to verify that the hidden chaotic attractor is found. Dynamic regions of attractors are illustrated to reveal seamless connections between self-excited and hidden chaotic attractors in the classical Lorenz system with wide ranges of parameters. [ABSTRACT FROM AUTHOR]

In present paper, authors examine the dynamics of a spring-slider model, considered as a phenomenological setup of a geological fault motion. Research is based on an assumption of delayed interaction between the two blocks, which is an idea that dates back to original Burridge–Knopoff model. In contrast to this first model, group of blocks on each side of transmission zone (with delayed interaction) is replaced by a single block. Results obtained indicate predominant impact of the introduced time delay, whose decrease leads to transition from steady state or aseismic creep to seismic regime, where each part of the seismic cycle (co-seismic, post-seismic and inter-seismic) could be recognized. In particular, for coupling strength of order 10 2 observed system exhibit inverse Andronov–Hopf bifurcation for very small value of time delay, τ≈0.01, when long-period (T = 12) and high-amplitude oscillations occur. Further increase of time delay, of order 10 −1 , induces an occurrence of a direct Andronov–Hopf bifurcation, with short-period (T = 0.5) oscillations of approximately ten times smaller amplitude. This reduction in time delay could be the consequence of the increase of temperature due to frictional heating, or due to decrease of pressure which follows the sudden movement along the fault. Analysis is conducted for the parameter values consistent with previous laboratory findings and geological observations relevant from the seismological viewpoint. [ABSTRACT FROM AUTHOR]