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In second part of the paper both classical and novel scenarios of transition from regular to chaotic dynamics of dissipative continuous mechanical systems are studied. A detailed analysis allowed us to detect the already known classical scenarios of transition from periodic to chaotic dynamics, and in particular the Feigenbaum scenario. The Feigenbaum constant was computed for all continuous mechanical objects studied in the first part of the paper. In addition, we illustrate and discuss different and novel scenarios of transition of the analysed systems from regular to chaotic dynamics, and we show that the type of scenario depends essentially on excitation parameters.

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.

In this paper the Tricomi problem for a nonlinear mixed type equation is studied. The coefficients of themixed type equation are discontinuous on the line, where the equation changes its type. The existence of solution to this problem is proved. The method developed in this paper can be applied to study more difficult problems for nonlinear mixed type equations arising in gas dynamics.

The purpose of this paper is to study necessary and sufficient condition for the strong convergence of a new parallel iterative algorithm with errors for two finite families of uniformly L -Lipschitzian mappings in Banach spaces. The results presented in this paper improve and extend the recent ones announced by [2–7].

This paper is concerned with the initial-boundary value problem for damped wave equations with a nonlinear convection term in the multi-dimensional half space R + n : (I) { u t t − Δ u + u t + div f ( u ) = 0 , t > 0 , x = ( x 1 , x ′ ) ∈ R + n ( : = R + × R n − 1 ) , u ( 0 , x ) = u 0 ( x ) → u + , as x 1 → + ∞ , u t ( 0 , x ) = u 1 ( x ) , u ( t , 0 , x ′ ) = u b , x ′ = ( x 2 , x 3 , ⋯ , x n ) ∈ R n − 1 . For the non-degenerate case f 1 ′ ( u + ) l 0 , it was shown in [10] that the above initial-boundary value problem (I) admits a unique global solution u(t,x) which converges to the corresponding planar stationary wave ϕ(x1) uniformly in x1 ∈ R+ as time tends to infinity provided that the initial perturbation and/or the strength of the stationary wave are sufficiently small. And in [10] Ueda, Nakamura, and Kawashima proved the algebraic decay estimates of the tangential derivatives of the solution u(t,x) for t → + ∞ by using the space-time weighted energy method initiated by Kawashima and Matsumura [5] and improved by Nishihkawa [7]. Moreover, by using the same weighted energy method, an additional algebraic convergence rate in the normal direction was obtained by assuming that the initial perturbation decays algebraically. We note, however, that the analysis in [10] relies heavily on the assumption that f 1 ′ ( u b ) l 0 . The main purpose of this paper is devoted to discussing the case of f 1 ′ ( u b ) ≥ 0 and we show that similar results still hold for such a case. Our analysis is based on some delicate energy estimates.

In this paper we suggest a new discrete spectroscopy for analysis of random signals and fluctuations. This discrete spectroscopy is based on successful solution of the modified Prony’s problem for the strongly-correlated random sequences. As opposed to the general Prony’s problem where the set of frequencies is supposed to be unknown in the new approach suggested the distribution of the unknown frequencies can be found for the strongly-correlated random sequences. Preliminary information about the frequency distribution facilitates the calculations and attaches an additional stability in the presence of a noise. This spectroscopy uses only the informative-significant frequency band that helps to fit the given signal with high accuracy. It means that any random signal measured in t-domain can be “read” in terms of its amplitude-frequency response (AFR) without model assumptions related to the behavior of this signal in the frequency region. The method overcomes some essential drawbacks of the conventional Prony’s method and can be determined as the non-orthogonal amplitude frequency analysis of the smoothed sequences (NAFASS). In this paper we outline the basic principles of the NAFASS procedure and show its high potential possibilities based on analysis of some actual NIR data. The AFR obtained serves as a specific fingerprint and contains all necessary information which is sufficient for calibration and classification of the informative-significant band frequencies that the complex or nanoscopic system studied might have.

In this paper, we study a one-dimensional motion of viscous gas near vacuum. We are interested in the case that the gas is in contact with the vacuum at a finite interval. This is a free boundary problem for the one-dimensional isentropic Navier-Stokes equations, and the free boundaries are the interfaces separating the gas from vacuum, across which the density changes discontinuosly. Smoothness of the solutions and the uniqueness of the weak solutions are also discussed. The present paper extends results in Luo-Xin-Yang [12] to the jump boundary conditions case.

In this paper, we consider an insurance company which has the option of investing in a risky asset and a risk-free asset, whose price parameters are driven by a finite state Markov chain. The risk process of the insurance company is modeled as a diffusion process whose diffusion and drift parameters switch over time according to the same Markov chain. We study the Markov-modulated mean-variance problem for the insurer and derive explicitly the closed form of the efficient strategy and efficient frontier. In the case of no regime switching, we can see that the efficient frontier in our paper coincides with that of [10] when there is no pure jump.

In this paper, we consider a degenerate steady-state drift-diffusion model for semiconductors. The pressure function used in this paper is ϕ ( s ) = s α ( α > 1 ) . We present existence results for general nonlinear diffusivities for the degenerate Dirichlet-Neumann mixed boundary value problem.

In this paper, synchronization of delayed fuzzy cellular neural networks has been considered. By construction a suitable Lyapunov functional and utilizing some inequality techniques, some sufficient conditions for synchronization of such a system are obtained. Simulation results are given to justify the theoretical analysis in this paper.

In this paper, we prove the controllability of a quasi-linear heat equation involving gradient terms with Fourier boundary conditions in a bounded domain of ℝN. The proofs of the main results in this paper involve such inequalities and rely on the study of these linear problems and appropriate fixed point arguments.

Synchronization is an important phenomenon commonly observed in nature. It is also often artificially induced because it is desirable for a variety of applications in physics, applied sciences and engineering. In a recent paper [Mahmoud GM, Mohamed AA, Aly SA. Strange attractors and chaos control in periodically forced complex Duffing’s oscillators. Physica A 2001;292:193–206], a system of periodically forced complex Duffing’s oscillators was introduced and shown to display chaotic behavior and possess strange attractors. Such complex oscillators appear in many problems of physics and engineering, as, for example, nonlinear optics, deep-water wave theory, plasma physics and bimolecular dynamics. Their connection to solutions of the nonlinear Schrodinger equation has also been pointed out. In this paper, we study the remarkable phenomenon of chaotic synchronization on these oscillator systems, using active control and global synchronization techniques. We derive analytical expressions for control functions and show that the dynamics of error evolution is globally stable, by constructing appropriate Lyapunov functions. This means that, for a relatively large set initial conditions, the differences between the drive and response systems vanish exponentially and synchronization is achieved. Numerical results are obtained to test the validity of the analytical expressions and illustrate the efficiency of these techniques for inducing chaos synchronization in our nonlinear oscillators.

In the control signal process theory, the state equation is an important approach for modelling, analyzing and designing a wide range of systems. Furthermore, the state equation is often the most efficient form from the standpoint of computer simulation for highly complex systems. The existing researches exploit the fact that for networks containing dependent sources, bridging elements and coupling elements, the derivation of the closed-form state equation becomes rather complicated. On the other hand, a simple and valuable unifying approach of finding the state equations for complicated physical systems is successfully presented in the paper. The new unifying approach needs only the substitution theorem and the author’s invented simple matrix operations. The main fascinating peculiarity of this approach is exposed in its systematic, graphic and human structure that improves the shortcomings of those traditional approaches. One comparative example is proposed to show the distinguished advantages our method offers over existing methods. In order to demonstrate the practical applicability, the paper has investigated an electronic operational-amplifier circuit that can be easily stabilized by our approach.

This paper introduces a modified Lu chaotic system, and some basic dynamical properties are studied. Based on these properties, we present hybrid dislocated control method for stabilizing chaos to unstable equilibrium and limit cycle. In addition, based on the Lyapunov stability theorem, general hybrid projective dislocated synchronization (GHPDS) is proposed, which includes complete dislocated synchronization, dislocated anti-synchronization and projective dislocated synchronization as its special item. The drive and response systems discussed in this paper can be strictly different dynamical systems (including different dimensional systems). As examples, the modified Lu chaotic system, Chen chaotic system and hyperchaotic Chen system are discussed. Numerical simulations are given to show the effectiveness of these methods.

In this paper, a chattering-free sliding mode controller design for uncertain chaotic systems is presented. Since the implementation of the sliding mode control may cause a significant problem of chattering, many modified methodologies have been developed to overcome this drawback. However, each of them has own problems such as lack of robustness against disturbance variations, steady-state error, large convergence time and effect on transient performance. This paper proposes an improved sliding mode control strategy in which a modified sliding condition in a continuous function in control signal is taken into account instead of discontinuous part and also it adds an auxiliary continuous control to the control input. Then, the stability of controlled system is proved by using Lyapunov’s direct method. The usefulness of this proposed method for eliminating the chattering phenomenon in transient and steady states, in the face of uncertain chaotic systems with disturbances, is well appeared. For this purpose, the Lorenz system is studied and its simulation results are presented to demonstrate the effectiveness of the proposed control scheme.

This paper studies the problem of delay-dependent robust stability for uncertain neutral system with mixed delays. Based on a novel augmented Lyapunov functional approach and linear matrix inequality technology, a new delay-dependent stability condition is derived. Since no restriction on the derivative of the time-varying discrete delay is needed, the criteria proposed in this paper are less conservative than some previous approaches. Numerical examples are given to show the effectiveness of the proposed methods and the influence of uncertainties to the stability of the neutral system.

In this paper, a hybrid method using active control and a High Order Differentiator (HOD) methodology is proposed to synchronize chaotic systems. Compared to some traditional active control methods, this new method can synchronize chaotic systems where only output states of the master system are available, i.e. the system is considered a black box. The HOD is used to estimate the derivative information of the master system followed by an active control methodology relying on HOD information. The Qi hyperchaotic system is used to verify the performance of this hybrid method. The proposed method is also compared to some traditional methods. Experimental results show that the proposed method has high synchronization precision and speed and is robust against uncertainties in the master system. The circus implements of the proposed synchronizing scheme are included in this paper. The simulation results show the feasibility of the proposed scheme.

At first, the paper described a brief history of communication in China. In 2008, the third generation (3G) telecommunication technologies began to develop. In Chinese 3G telecommunication market, there are three oligopolistic competitors. In order to study competing process of the triopoly, the paper considered a Bertrand model with bounded rational. A triopoly game is modeled by three nonlinear difference equations. By using the theory of bifurcations of dynamical systems, the existence and stability for the equilibria of this system were obtained. Numerical simulations were used to show bifurcations diagrams, the maximum Lyapunov exponent and sensitive dependence on initial conditions. We observed that increasing the speed of adjustment of bounded rational player might change the stability of Nash equilibrium point and cause bifurcation and chaos to occur. Thus, it will be difficult to make strategy and to forecast for each enterprise. It might cause the telecom markets to be irregular. The analysis and results in this paper are important for Chinese telecommunication markets, the same to mathematics.

In this paper, impulsive Cohen–Grossberg neural networks with delay is studied. Sufficient conditions are given to guarantee the realization of complete synchronization for Cohen–Grossberg neural networks with delay and large impulse under noise perturbation by stochastic Halanay inequality. Moreover, an example is given to show the effectiveness of synchronization design in this paper.

In this paper, reaction–diffusion Cohen–Grossberg neural networks (RDCGNN) with varying delay and Robin boundary conditions is studied by Halanay inequality and Young inequality, and sufficient conditions are given to guarantee global exponential stability of the equilibrium point. The proof of main result improves the earlier finding. Moreover, RDCGNN with large impulse also is investigated. Finally, a numerical example is given to show the effectiveness of the results in this paper.

In this paper, we have tried to apply the concepts of fuzzy set to Lie groups and fuzzy differential invariant (FDI) in order to provide suitable conditions for applying Lie symmetry method in solving fuzzy differential equations (FDEs). For this, we define a C 1 -fuzzy submanifold and fuzzy immersion with some examples. In main section, we defined the fuzzy Lie group and some its relative concepts such as fuzzy transformation group and fuzzy G-invariant. The goal of this paper is to introduce and study new defining for fuzzy Lie group and fuzzy differential invariant (FDI). Also, some illustrative examples are given.

The construction of cryptographically strong substitution boxes (S-boxes) is an important concern in designing secure cryptosystems. The key-dependent S-boxes designed using chaotic maps have received increasing attention in recent years. However, the key space of such S-boxes does not seem to be sufficiently large due to the limited parameter range of discretized chaotic maps. In this paper, we propose a new key-dependent S-box based on the iteration of continuous chaotic maps. We explore the continuous-valued state space of chaotic systems, and devise the discrete mapping between the input and the output of the S-box. A key-dependent S-box is constructed with the logistic map in this paper. We show that its key space could be much larger than the current key-dependent chaotic S-boxes.

Image encryption is somehow different from text encryption due to some inherent features of image such as bulk data capacity and high correlation among pixels, which are generally difficult to handle by conventional methods. The desirable cryptographic properties of the chaotic maps such as sensitivity to initial conditions and random-like behavior have attracted the attention of cryptographers to develop new encryption algorithms. Therefore, recent researches of image encryption algorithms have been increasingly based on chaotic systems, though the drawbacks of small key space and weak security in one-dimensional chaotic cryptosystems are obvious. This paper proposes a Coupled Nonlinear Chaotic Map, called CNCM, and a novel chaos-based image encryption algorithm to encrypt color images by using CNCM. The chaotic cryptography technique which used in this paper is a symmetric key cryptography with a stream cipher structure. In order to increase the security of the proposed algorithm, 240 bit-long secret key is used to generate the initial conditions and parameters of the chaotic map by making some algebraic transformations to the key. These transformations as well as the nonlinearity and coupling structure of the CNCM have enhanced the cryptosystem security. For getting higher security and higher complexity, the current paper employs the image size and color components to cryptosystem, thereby significantly increasing the resistance to known/chosen-plaintext attacks. The results of several experimental, statistical analysis and key sensitivity tests show that the proposed image encryption scheme provides an efficient and secure way for real-time image encryption and transmission.

In this paper, the problem of robust stability for uncertain linear neutral systems with discrete and distributed delays is considered. The uncertainties under consideration are norm bounded, and possibly time varying. Some novel delay-dependent stability criteria are derived and formulated in the form of a linear matrix inequalities (LMIs) by a new class of Lyapunov–Krasovskii functionals which is constructed based on the descriptor model of the system and the method of decomposition. The new criteria are less conservative than the existing ones. Numerical examples illustrate that the proposed criteria are effective and achieve significant improvement over the results proposed in previous paper.

Remarkably benign looking logistic transformations x n +1 = r x n (1 − x n ) for choosing x 0 between 0 and 1 and 0 r ⩽ 4 have found a celebrated place in chaos, fractals and discrete dynamics. The strong physical meaning of Mandelbrot and Julia sets is broadly accepted and nicely connected by Christian Beck [Beck C. Physical meaning for Mandelbrot and Julia sets. Physica D 1999;125(3–4):171–182. Zbl0988.37060] to the complex logistic maps, in the former case, and to the inverse complex logistic map, in the latter case. The purpose of this paper is to study the bounded behavior of the complex logistic map using superior iterates and generate fractals from the same. The analysis in this paper shows that many beautiful properties of the logistic map are extendable for a larger value of r .

Evolutionary Algorithms (EAs) are stochastic and robust meta-heuristics of evolutionary computation field useful to solve optimization problems in image processing applications. Recently, as special mechanism to avoid being trapped in local minimum, the ergodicity property of chaotic sequences has been used in various designs of EAs. Three differential evolution approaches based on chaotic sequences using logistic equation for image enhancement process are proposed in this paper. Differential evolution is a simple yet powerful evolutionary optimization algorithm that has been successfully used in solving continuous problems. The proposed chaotic differential evolution schemes have fast convergence rate but also maintain the diversity of the population so as to escape from local optima. In this paper, the image contrast enhancement is approached as a constrained nonlinear optimization problem. The objective of the proposed chaotic differential evolution schemes is to maximize the fitness criterion in order to enhance the contrast and detail in the image by adapting the parameters using a contrast enhancement technique. The proposed chaotic differential evolution schemes are compared with classical differential evolution to two testing images. Simulation results on three images show that the application of chaotic sequences instead of random sequences is a possible strategy to improve the performance of classical differential evolution optimization algorithm.

In this paper, we transmute the solution for a new system of linear variational inequalities to an equilibrium point of neural networks, and by using analytic technique, some sufficient conditions are presented. Further, the estimation of the exponential convergence rates of the neural networks is investigated. The new and useful results obtained in this paper generalize and improve the corresponding results of recent works.

This paper proposes three different attacks on a recently proposed chaotic cryptosystem in [Li P, Li Z, Halang WA, Chen G. A stream cipher based on a spatiotemporal chaotic system. Chaos, Solitons & Fractals 2007;32:1867–76]. The cryptosystem under study displays weakness in the generation of the keystream. The encryption is made by generating a keystream mixed with blocks generated from the plaintext. The so obtained keystream remains unchanged for every encryption procedure. Moreover, its generation does neither depend on the plaintext nor on the ciphertext, that’s to say, the keystream remains unchangeable for every plaintext with the same length. Guessing the keystream leads to guessing the key. This paper presents three possible attacks able to break the whole cryptosystem based on this drawback in generating the keystream.

In this paper, a new scheme is proposed to eliminate the useless spiral wave and turbulence in the excitable media. The activator amplitudes of few sites in the media are sampled and restricted within the appropriate thresholds. At first, the local control is imposed on the center of the media, and then the local control is introduced into the left border in the media. The numerical simulation results confirm that the whole media can reach homogeneous within few time units even if the spatiotemporal noise is imposed on the whole media. To check the model independence of this scheme, the scheme is used to remove the spiral wave in the Fitzhugh–Nagumo model firstly. In our numerical simulation, the whole system is discretized into 400 × 400 sites. Then the scheme is used to eliminate the stable rotating spiral wave, meandering spiral and spiral turbulence in the modified Fitzhugh–Nagumo model, respectively. Finally, this scheme is used to remove the stable rotating spiral wave in the Belousov–Zhabotinsky (BZ) reaction. All the results just confirm its effectiveness to eliminate the spiral wave and turbulence. The criterion for thresholds selection is also discussed in the end of this paper.

A model describing a gravitational effect into a forming gravitating and rotating cosmological body based on the statistical theory has been proposed. In this model, the forming cosmological bodies are shown to have fuzzy contours and are represented by spheroidal forms. The proposed theory starts from the conception for forming a spheroidal body from a gas-dust protoplanetary nebula. The distribution functions together with the mass densities and gravitational field potentials for an immovable spheroidal body as well as rotating one have been derived. This work also considers problem of gravitational condensation of a gas-dust protoplanetary cloud with a view to protoplanet formation in its own gravitational field. It is known a protoplanetary system behavior can be described by Jeans’ equation in partial derivations relative to a distribution function. The paper derives a more general evolutional equation which generalizes the Jeans’ equation. Since the determination of gravitational potential (and mass density) is the main problem of statistical dynamics for protoplanetary system, then the work shows how this task of protoplanetary dynamics can be solved on the basis of the proposed spheroidal body theory. Within the framework of this theory, the distribution function of a specific angular momentum of a rotating uniformly spheroidal body has been found. As the specific angular momentums are averaged during a conglomeration process, the specific angular momentum of a protoplanet for a planetary system is found in this paper. The proposed theory is also applied to investigate formation of planets in our solar system. As a result, a new law for the solar system planetary distances (which generalizes the well-known Schmidt law) is derived in this paper. It has been shown that the new law gives a very good estimation of observable planetary distances in the solar system.

Quadratic programming has been widely applied to solving real-world problems. Recently, Liu describes a solution method for solving a class of fuzzy quadratic programming problems, where the cost coefficients of the linear terms in objective function, constraint coefficients, and right-hand sides are fuzzy numbers [Liu ST. Quadratic programming with fuzzy parameters: a membership function approach. Chaos, Solitons & Fractals 2009;40:237–45]. In this paper, we generalize Liu’s method to a more general fuzzy quadratic programming problem, where the cost coefficients in objective function, constraint coefficients, and right-hand sides are all fuzzy numbers. A pair of two-level mathematical programs is formulated to calculate the upper bound and lower bound of the objective values of the fuzzy quadratic program. Based on the duality theorem and by applying the variable transformation technique, the pair of two-level mathematical programs is transformed into a family of conventional one-level quadratic programs. Solving the pair of quadratic programs produces the fuzzy objective values of the problem. With the ability of calculating the fuzzy objective value developed in this paper, it might help initiate wider applications.

Fractals in nature are always a result of some growth process. The language of fractals which has been created specifically for the description of natural growth process is called L-systems. Recently, superior iterations (essentially, investigated by Mann [Mann WR. Mean value methods in iteration. Proc Am Math Soc 1953;4:506–10 [MR0054846 (14,988f)]]) has been introduced in the study of fractal and chaos. In this paper, inspired by superior iterates, we have generated fractal plants categorically using stochastic L-system. Some beautiful plants are also given in the paper.

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.

This work examines the control of self-excited vibration of a simply-supported beam subjected to an axially high-frequency excitation. The investigation of the resonant cases are not considered in this paper. The control is implemented via a corrective position feedback with time delay. The objective of this control is to eliminate the undesirable self-excited vibrations with an appropriate choice of parameters. The issue of stability is also addressed in this paper. Using the technique of direct partition of motion, the dynamic of discretized equations is separated into slow and fast components. The multiple scales method is then performed on the slow dynamic to obtain a slow flow for the amplitude and phase. Analysis of this slow flow provides analytical approximations locating regions in parameters space where undesirable self-excited vibration can be eliminated. A numerical study of these regions is performed on the original discretized system and compared to the analytical prediction showing a good agreement.

This paper illustrates an approach to generate multi-wing attractors in coupled Lorenz systems. In particular, novel four-wing (eight-wing) hyperchaotic attractors are generated by coupling two (three) identical Lorenz systems. The paper shows that the equilibria of the proposed systems have certain symmetries with respect to specific coordinate planes and the eigenvalues of the associated Jacobian matrices exhibit the property of similarity. In analogy with the original Lorenz system, where the two-wings of the butterfly attractor are located around the two equilibria with the unstable pair of complex-conjugate eigenvalues, this paper shows that the four-wings (eight-wings) of these attractors are located around the four (eight) equilibria with two (three) pairs of unstable complex-conjugate eigenvalues.

In a recent paper [Soleimani-damaneh M. Fuzzy upper bounds and their applications. Chaos, Solitons & Fractals 2008;36:217–25.], I established the existence of a distance-based fuzzy upper bound for the objective function of a fuzzy DEA model, using the properties of a discussed signed distance, and provided an effective approach to solve that model. In this paper a new dual-based proof for the existence of the above-mentioned upper bound is provided which gives a useful insight into the theory of fuzzy DEA.

In this paper, several classes of impulsive Cohen–Grossberg neural networks with continuously distributed delays are considered. Global exponential stability and robust global exponential stability of the equilibrium solution are investigated by using Lyapunov function and integro-differential inequality. Moreover, sufficient conditions are also given to guarantee the existence of ϖ-periodic solution and that all other solutions are convergent to it globally exponentially. Finally, two examples are given to demonstrate the effectiveness of our results in this paper.

This paper proposes a novel particle swarm optimization (PSO) algorithm, chaotically encoded particle swarm optimization algorithm (CENPSOA), based on the notion of chaos numbers that have been recently proposed for a novel meaning to numbers. In this paper, various chaos arithmetic and evaluation measures that can be used in CENPSOA have been described. Furthermore, CENPSOA has been designed to be effectively utilized in data mining applications.

Since the investigation of impulsive delay differential equations is beginning, the literature on delay epidemic models with pulse vaccination is not extensive. In this paper, we propose a new SEIRS epidemic disease model with two profitless delays and vertical transmission, and analyze the dynamics behaviors of the model under pulse vaccination. Using the discrete dynamical system determined by the stroboscopic map, we obtain a ‘infection-free’ periodic solution, further, show that the ‘infection-free’ periodic solution is globally attractive when some parameters of the model are under appropriate conditions. Using a new modeling method, we obtain sufficient condition for the permanence of the epidemic model with pulse vaccination. We show that time delays, pulse vaccination and vertical transmission can bring different effects on the dynamics behaviors of the model by numerical analysis. Our results also show the delays are “profitless”. In this paper, the main feature is to introduce two discrete time delays, vertical transmission and impulse into SEIRS epidemic model and to give pulse vaccination strategies.

In this paper, the anti-synchronization of a general class of chaotic systems is investigated. A simple adaptive feedback scheme is proposed to anti-synchronize many familiar chaotic systems, including autonomous systems and non-autonomous systems. Lyapunov analysis for the error system gives the asymptotic stability conditions based on the invariance principle of differential equations. The schemes are successfully applied to three groups of examples: the van der Pol–Duffing oscillator, the parametrically harmonically excited 4D system, and the additionally harmonically excited Murali–Lakshmanan–Chua circuit. Numerical results are presented to justify the theoretical analysis in this paper.

Let k: be a field and q a nonzero element in k such that the square roots of q are in k. We use Hq to denote an affine Hecke algebra over k of type with parameter q. The purpose of this paper is to study representations of Hq by using based rings of two-sided cells of an affine Weyl group W of type . We shall give the classification of irreducible representations of Hq. We also remark that a calculation in [11] actually shows that Theorem 2 in [1] needs a modification, a fact is known to Grojnowski and Tanisaki long time ago. In this paper we also show an interesting relation between Hq and an Hecke algebra corresponding to a certain Coxeter group. Apparently the idea in this paper works for all affine Weyl groups, but that is the theme of another paper.

In this paper, the problem of robust exponential stability for a class of interval Cohen–Grossberg neural networks with time-varying delays is investigated. Without assuming the boundedness and differentiability of the activation functions and any symmetry of interconnection matrices, some sufficient conditions for the existence, uniqueness, and global robust exponential stability of the equilibrium point are derived. Some comparisons between the results presented in this paper and the previous results admit that our results are the improvement and extension of the existed ones. The validity and performance of the new results are further illustrated by two simulation examples.

Starting from the delay Lienard 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.

Chaotic cryptology has been widely investigated recently. A common feature in the most recent developments of chaotic cryptosystems is the use of a single dynamical rule in the encoding–decoding process. The main objective of this paper is to provide a set of chaotic systems instead of a single one for cryptography. In this paper, we introduce a chaotic cryptosystem based on the symbolic dynamics of random maps with position dependent weighting probabilities. The random maps model is a deterministic dynamical system in a finite phase space with n points. The maps that establish the dynamics of the system are chosen randomly for every point. The essential idea of this paper is that, given two dynamical systems that behave in a certain way, it is possible to combine them (by composing) into a new dynamical system. This dynamically composed system behaves in a completely different way compared to the constituent systems. The proposed scheme exploits the symbolic dynamics of a set of chaotic maps in order to encode the binary information. The performance of the new cryptosystem based on chaotic dynamical systems properties is examined. Both theoretical and experimental results demonstrate that the proposed algorithm using symbolic dynamics achieves the optimal security criteria.

Comprehensive numerical simulations (reviewed in Dissipative Solitons, Akhmediev and Ankiewicz (Eds.), Springer, Berlin, 2005) of pulse solutions of the cubic–quintic Ginzburg–Landau Equation (CGLE), a canonical equation governing the weakly nonlinear behavior of dissipative systems in a wide variety of disciplines, reveal various intriguing and entirely novel classes of solutions. In particular, there are five new classes of pulse or solitary waves solutions, viz. pulsating, creeping, snake, erupting, and chaotic solitons. In contrast to the regular solitary waves investigated in numerous integrable and non-integrable systems over the last three decades, these dissipative solitons are not stationary in time. Rather, they are spatially confined pulse-type structures whose envelopes exhibit complicated temporal dynamics. The numerical simulations also reveal very interesting bifurcations sequences of these pulses as the parameters of the CGLE are varied. In this paper, we address the issues of central interest in the area, i.e., the conditions for the occurrence of the five categories of dissipative solitons, as well the dependence of both their shape and their stability on the various parameters of the CGLE, viz. the nonlinearity, dispersion, linear and nonlinear gain, loss and spectral filtering parameters. Our predictions on the variation of the soliton amplitudes, widths and periods with the CGLE parameters agree with simulation results. First, we elucidate the Hopf bifurcation mechanism responsible for the various pulsating solitary waves, as well as its absence in Hamiltonian and integrable systems where such structures are absent. Next, we develop and discuss a variational formalism within which to explore the various classes of dissipative solitons. Given the complex dynamics of the various dissipative solutions, this formulation is, of necessity, significantly generalized over all earlier approaches in several crucial ways. Firstly, the starting formulation for the Lagrangian is recent and not well explored. Also, the trial functions have been generalized considerably over conventional ones to keep the shape relatively simple (and the trial function integrable!) while allowing arbitrary temporal variation of the amplitude, width, position, speed and phase of the pulses. In addition, the resulting Euler–Lagrange equations are treated in a completely novel way. Rather than consider the stable fixed points which correspond to the well-known stationary solitons or plain pulses, we use dynamical systems theory to focus on more complex attractors viz. periodic, quasiperiodic, and chaotic ones. Periodic evolution of the trial function parameters on stable periodic attractors yield solitons whose amplitudes and widths are non-stationary or time dependent. In particular, pulsating and snake dissipative solitons may be treated in this manner. Detailed results are presented here for the pulsating solitary waves – their regimes of occurrence, bifurcations, and the parameter dependences of the amplitudes, widths, and periods agree with simulation results. Snakes and chaotic solitons will be addressed in subsequent papers. This overall approach fails only to address the fifth class of dissipative solitons, viz. the exploding or erupting solitons.

This paper considers the global output convergence of Cohen–Grossberg neural networks with both time-varying and distributed delays. The inputs of the neural networks are required to be time-varying and the activation functions should be globally Lipschitz continuous and monotonely nondecreasing. Based on M-matrix theory, several sufficient conditions are established to guarantee the global output convergence of this class of neural networks. Symmetry in the connection weight matrices and the boundedness of the activation functions are abandoned in this paper. The convergence results are useful in solving some optimization problems and the design of Cohen–Grossberg neural networks with both time-varying and distributed delays. Two examples are given to illustrate the effectiveness of our results.

This paper deals with the observer-based synchronization in a cascade connection of hyperchaotic discrete-time systems. The paper demonstrates that exact synchronization in finite time is achievable between pairs of drive–response systems using only a scalar synchronizing signal. This “propagated synchronization” starts from the innermost drive–response system pair and propagates toward the outermost drive-system pair. Choosing the drive-system input to be an information signal (encrypted via an arbitrary encryption function) yields a potential application of this architecture in chaos-based communications.

In this paper, the stability of neural networks with both variable and unbounded delays is investigated. With simpler assumption that the activation functions are continuous and monotone non-decreasing, we employ homeomorphism techniques and Lyapunov functional to establish some sufficient conditions ensuring the global asymptotic stability and exponential stability of equilibrium of neural networks with both variable and unbounded delays. The new and useful results obtained in this paper extend and improve the existing ones in the previous literature.

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 Poincare 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 Poincare 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.

In this paper, an efficient modification of the Adomian decomposition method by using Legendre polynomials is presented. Both linear and non-linear models are suited for the proposed method. Some examples here in are solved by using this method and this paper will demonstrate that the results are more reliable and efficient.