混合编程在Lorenz混沌系统动力学行为仿真中应用

Lorenz混沌系统的动力学行为是由控制参数决定。以Lorenz混沌系统的动力学行为为实例,采用更加直观的相图和时域图并借助于Lab VIEW与MATLAB软件对之进行仿真,实现系统的动力学行为。分析了Lab VIEW与MATLAB两种编程语言的特点和混合编程技术,采用两者混合编程技术实现了有效仿真,给出了混合编程的具体实现过程。实践证明,Lab VIEW与MATLAB的结合运用,简单可行,相互补充,有利于程序的仿真,提高编程效率。

控制一类磁性刚体航天器的混沌姿态运动

本文研究一类磁性航天器的混沌姿态运动及其控制。建立了在近地球赤道面圆轨道上运动受万有引力矩、磁力矩作用磁性刚体航天器姿态运动的动力学方程。采用时间历程、Poincare截面、Lyapunov指数和功率谱对系统的动力学行为进行数值识别,结果表明随着磁场参数的增大系统动力学行为由准周期环面破裂而出现混沌。利用输入—输出反馈精确线性化的方法将航天器的混沌姿态运动控制为姿态静止和按给定的周期规律运动,数值结果表明该控制方法的有效性。

Bifurcations of Exact Traveling Wave Solutions for(2+1)-Dimensional HNLS Equation

For the(2+1)-Dimensional HNLS equation,what are the dynamical behavior of its traveling wave solutions and how do they depend on the parameters of the systems? This paper will answer these questions by using the methods of dynamical systems.Ten exact explicit parametric representations of the traveling wave solutions are given.

Assessing China 2030 carbon emissions from fossil fuels:based on system dynamics model

The Chinese government has set ambitious targets to reduce the per unit of GDP by 40% ~45% during 2005 to 2020 and achieve the intensity peaking of carbon emissions of CO2 emissions a- round 2030. The T21 national development model for China was developed for the purpose of analy- zing the effects of long-term national policies that relate to carbon emissions, loss of farm land, water shortage, energy security, food security, and their contributions to this reduction target. The focus of this paper is on the policies that have substantial impacts on carbon emissions from fossil fuels. Four scenarios are developed with the model to simulate future carbon emissions ： 1 ） the BAU （ busi- ness as usual） scenario, showing the likely results of continuing current policies; 2 ） the TECH （technology） scenario showing the effects of more investment in renewable energy sources and promoting more energy efficient technologies; 3 ） the BEHAVIOR scenario, showing how government tax and price policies, together with public education programs, would instigate behaviour changes towards more sustainable living; and 4 ） the TECH＆BEHA scenario, which shows the results of combining scenarios 2 and 3. The simulation results show that CO2 emissions reduction targets of China are achievable, but also require great effort to put in.

Cluster Growth Through Monomer Adsorption Processes

We propose a monomer adsorption model, in which only the monomers are allowed to diffuse and adsorb onto other clusters. By means of the generalized rate equation we investigate the kinetic behavior of the system with a special rate kernel. For the system without monomer input, the concentration aj（t） of the Aj clusters （j 〉 1） asymptotically retains a nonzero quantity, while for the system with monomer input, it decays with time and vanishes finally. We also investigate the kinetics of an interesting model with fixed-rate monomer adsorption. For the ease without monomer source, the evolution of the system will halt at a finite time; while the system evolves infinitely in time in the case with monomer source. Finally, we also suggest a connection between the fixed-rate monomer adsorption systems and growing networks.

Comparing dynamical systems concepts and techniques for biomechanical analysis

Traditional biomechanical analyses of human movement are generally derived from linear mathematics.While these methods can be useful in many situations,they do not describe behaviors in human systems that are predominately nonlinear.For this reason,nonlinear analysis methods based on a dynamical systems approach have become more prevalent in recent literature.These analysis techniques have provided new insights into how systems(1) maintain pattern stability,(2) transition into new states,and(3) are governed by short-and long-term(fractal) correlational processes at different spatio-temporal scales.These different aspects of system dynamics are typically investigated using concepts related to variability,stability,complexity,and adaptability.The purpose of this paper is to compare and contrast these different concepts and demonstrate that,although related,these terms represent fundamentally different aspects of system dynamics.In particular,we argue that variability should not uniformly be equated with stability or complexity of movement.In addition,current dynamic stability measures based on nonlinear analysis methods(such as the finite maximal Lyapunov exponent) can reveal local instabilities in movement dynamics,but the degree to which these local instabilities relate to global postural and gait stability and the ability to resist external perturbations remains to be explored.Finally,systematic studies are needed to relate observed reductions in complexity with aging and disease to the adaptive capabilities of the movement system and how complexity changes as a function of different task constraints.

Dynamics and circuit implementation of three simplified chaotic systems

To improve the performance of chaotic secure communication,three simplified chaotic systems with one variable parameter were investigated.Basic properties were analyzed including symmetry,dissipation and topological structure.Complex dynamical behaviors of the systems including chaos and periodic orbits were verified by numerical simulations,Lyapunov exponents and bifurcation diagrams.Interestingly,the three systems were integrated in a common circuit,and their dynamical behaviors were easily observed by adjusting regulable resistors R28,R14 and R17,respectively,and the relations between the variable resistor and the system parameter were deduced.The circuit experiment results agree well with the simulation results.Finally,a secure communication scheme based on chaos shift keying(CSK) was presented,which lays an experiment foundation for chaotic digital secure communication.

Analysis of 1/2 sub-harmonic resonance in a maneuvering rotor system

This paper focuses on the 1/2 sub-harmonic resonance of an aircraft’s rotor system under hovering flight that can be modeled as a maneuver load G in the equations of motion.The effect on the rotor system is analyzed by using theoretical methods.It is shown that the sub-harmonic resonance may occur due to maneuvering flight conditions.The larger the eccentricity E and the maneuver load G,the greater the sub-harmonic resonance.The effects of nonlinear stiffness,damping of the system,maneuver load,and eccentricity on the sub-harmonic resonance region in parameter planes are also investigated.Bifurcation diagrams of the analytical solutions are in good agreement with that of the numerical simulation solutions.These results will contribute to the understanding of the nonlinear dynamic behaviors of maneuvering rotor systems.

Dynamical behaviors of a diffusive predator-prey system with Beddington-DeAngelis functional response

In this paper, we present a diffusive predator prey system with Beddington-DeAngelis funetionM response, where the prey species can disperse between the two patches, and there is competition between the two predators. Sufficient conditions for the permanence and extinction of system are established based on the upper and lower solution meth- ods and comparison theory of differential equation. Furthermore, the global asymptotic stability of positive solutions is obtained by constructing a suitable Lyapunov function. By using the continuation theorem in coincidence degree theory, we show the periodicity of positive solutions. Finally, we illustrate global asymptotic stability of the model by a simulation figure.

Dynamics behaviors of a delayed competitive system in a random environment

In the real world, the population systems are often subject to white noises and a system with such stochastic perturbations tends to be suitably modeled by stochastic differential equations. This paper is concerned with the dynamic behaviors of a delay stochastic competitive system. We first obtain the global existence of a unique positive solution of system. Later, we show that the solution of system will be stochastically ultimate boundedness. However, large noises may make the system extinct exponentially with probability one. Also, sufficient conditions for the global attractivity of system are established. FinMly, illustrated examples are given to show the effectiveness of the proposed criteria.

OVERVIEW OF COMPLEX SYSTEMS IN SPORT

The complex systems approach offers an opportunity to replace the extant pre-dominant mechanistic view on sport-related phenomena.The emphasis on the environment-system relationship,the applications of complexity principles,and the use of nonlinear dynamics mathematical tools propose a deep change in sport science.Coordination dynamics,ecological dynamics,and network approaches have been successfully applied to the study of different sport-related behaviors,from movement patterns that emerge at different scales constrained by specific sport contexts to game dynamics.Sport benefit from the use of such approaches in the understanding of technical,tactical,or physical conditioning aspects which change their meaning and dilute their frontiers.The creation of new learning and training strategies for teams and individual athletes is a main practical consequence.Some challenges for the future are investigating the influence of key control parameters in the nonlinear behavior of athlete-environment systems and the possible relatedness of the dynamics and constraints acting at different spatio-temporal scales in team sports.Modelling sport-related phenomena can make useful contributions to a better understanding of complex systems and vice-versa.

THE DYNAMICAL BEHAVIOR OF NON-SMOOTH SYSTEM WITH IMPULSIVE CONTROL STRATEGIES

Non-smooth system including impulsive strategies at both fixed and unfixed times are analyzed. For the model with fixed impulsive effects, the global stability of pest eradi- cation periodic solution and the dominance of dynamic behavior are investigated. This indicates that the model with fixed moments has the potential to protect the natural enemies from extinction, but under some conditions may also serve to extinction of the pest. The second model is constructed according to the practices of IPM, that is, when the pest population reaches the economic injury level, a combination of biological, cultural, and chemical tactics that reduce pests to tolerable levels is used. Numerical investigations imply that there are several different types of periodic solutions and their maximum amplitudes are always less than the given economic threshold. The results also show that the time series at which the IPM strategies are applied are quite complex, which means that the application and realization of IPM in practice are very difficult.

THE DYNAMICAL MODELS OF ACTIVATED SLUDGE SYSTEM： STOCHASTIC CELLULAR AUTOMATON AND DIFFERENTIAL EQUATIONS

A stochastic celhflar automaton （CA） model for activated sludge system （ASS） is for- mulated by a series of transition functions upon realistic treatment processes, and it is tested by comparing with ordinary differential equations （ODEs） of ASS. CA system performed by empirical parameters can reflect the characteristics of fluctuation, com- plexity and strong non-linearity of ASS. The results show that the predictions of CA are approximately similar to the dynamical behaviors of ODEs. Based on the extreme experimental system with complete cell recycle in model validation, the dynamics of biomass and substrate are predicted accurately by CA, but the large errors exist in ODEs except for integrating more spatially complicated factors. This is due to that the strong mechanical stress from spatial crowding effect is ignored in ODEs, while CA system as a spatially explicit model takes account of local interactions. Despite its extremely simple structure, CA still can capture the essence of ASS better than ODEs, thus it would be very useful in predicting long-term dynamics in other similar systems.

New 0D/1D Physical Approach for Modelling the Gas Dynamics Behavior Inside the Intake System of an Engine

The competition among carmakers to introduce the most innovative solutions is growing day by day. Since few years, simulation is being used widely in automotive industries. Instead of building costly prototypes and expending fuel for doing tests on a real engine, simulation became a good solution before taking new decisions. Concerning the study of gas dynamics and pressure wave's propagation in the intake system of an internal combustion engine, a precise modelling is needed in order to obtain good results. Unfortunately, the computational time for these simulations is considered as high compared to the real time. The main objective of the new approach presented in this paper, is to reduce simulation time of models in the internal combustion engine simulation code, allowing them to accomplish many engine simulations faster than one-dimensional non-linear approach. A transfer function is defined to link directly the relative pressure and the air mass flow rate. In a second time, the model is included into an internal combustion engine simulation code. The results obtained with this code are compared to experimental ones which are measured on a one-cylinder engine test bench. A good agreement is obtained between the experimental results and the numerical one. The model was improved by adding a transfer function for temperature evolution. The convergence time is then reduced as well as the global simulation time of the model.

Preface

Clinical medicine and experiments have shown that electrophysiological activities on neuronal disease systems such as the epilepsy and Parkinson can exhibit the evolutions of complex dynamical behaviors and their transitions, which are closely related to the generation mechanism of neuronal diseases. Traditionally, electrophysiological activities have been analyzed from the statistical methods. Although some ideal results have been obtained, mechanisms of complex electrophysiological activities in neuronal systems cannot yet be disclosed. Dynamics modelling can help researchers to explore the mechanisms of electro- physiological activities of neuronal disease systems. By constructing reasonable physiological dynamical model, inner relation between the dynamics model and representation behaviors of the neuronal disease systems can be further studied. In addition, based on the constructed network model, we can also explore mechanisms of the evolutions of dynamical behaviors and their transitions of the initiation, propagation and termination of different kinds of the seizures. Finally, we can design the feasible control method to regulate dynamics behaviors of the seizures so as to realize the healthy neuronal firings.

THE DYNAMICAL BEHAVIOR ON THE CARRYING SIMPLEX OF A THREE-DIMENSIONAL COMPETITIVE SYSTEM： II. HYPERBOLIC STRUCTURE SATURATION

A competitive system on the n-rectangle： {x ∈ Rn： 0 ≤ xi ≤ li, i = 1,... ,n} was con- sidered, each species of which, in isolation, admits logistic growth with the hyperbolic structure saturation. It has an （n - 1）-dimensional invariant surface called carrying simplex E as a globe attractor, hence the long term dynamics of the system is com- pletely determined by the dynamics on E. For the three-dimensional system, the whole dynamical behavior was presented. It has a unique positive equilibrium point and any limit set is either an equilibrium point or a limit cycle. The system is permanent and it is proved that the number of periodic orbits is finite and non-periodic oscillation the May Leonard phenomenon does not exist. A criterion for the positive equilibrium to be globally asymptotically stable is provided. Whether there exist limit cycles or not remains open.