中立型大系统的渐近稳定性

文[1]—[3]研究了中立型大系统的稳定性,获得了一些较好的结果。对相对中立型系统来讲,滞后线性系统的稳定性理论已比较完善。本文所提供的方法能较有效地克服判断中立型大系统稳定性的困难,所获得的结果不同于所有已知结果,并补充了这方面的研究。 1.线性系统我们考虑线性中立型大系统     

测度型区间脉冲系统的稳定性

首次提出并研究了测度型区间脉冲系统的稳定性问题。基于代数Ｒｉｃｃａｔｉ方程，对测度型区间脉冲系统建立了若干全局指数稳定性判据。     

中立型时滞大系统的稳定性

本文研究非线性中立型有界时滞大系统和非线性中立型无界时滞大系统在C空间中的稳定性,获得了简洁、实用的稳定性代数充分准则。本文还对非线性时滞大系统的稳定性进行了研究,建立起一个高维时滞微分不等式,推广了著名的Halanay时滞微分不等式。     

广义中立型系统的渐近稳定性

讨论了广义中立型延迟系统理论的渐近稳定性，给出了广义中立型系统渐近稳定的一些充分条件。     

一类非线性中立型系统的渐近稳定性

基于李雅普诺夫泛函方法，本文讨论了一类非线性中立型系统渐近稳定性的充分条件，推广了中立型系统稳定性结果。最后，通过实例及其仿真数值模拟验证了上述理论结果。     

具滞后中立型线性大系统的指数稳定性

采用具有加权向量范数型李雅谱诺夫函数，对具滞后中立型线型大系统进行模型集结，得到集结系统；再运用比较原理与时域中的微分积分不等式，讨论相应集结系统，从而通过集结系统的稳定性，获得了具滞后中立型大系统的指数稳定性。     

中立型积分微分方程的稳定性

本文研究了一类中立型积分微分方程的稳定性，在相应的常微分系统完全可不稳定的条件下，获得了稳定性判别准则．     

具有参数不确定性的线性中立型时变时滞系统的鲁棒稳定性

本文研究一类具有参数不确定性的线性中立型时变时滞系统的鲁棒稳定性.首先,利用Jensen’s不等式,并采用新方法来处理积分项,得到标称中立型系统的稳定性判据.然后,基于标称系统的稳定性结果,进一步得到系统矩阵存在不确定性时的鲁棒稳定性判据.本文的新方法能充分利用负定项的信息,故稳定性结果的保守性更低.最后,两个数值例子分别验证了文中所得的标称中立型系统稳定性判据的保守性更低,以及系统矩阵存在不确定性时的鲁棒稳定性判据的可行性.     

基于Razumikhin-Type理论的中立型随机切换非线性系统的P阶矩稳定性与几乎必然稳定性

研究了中立型随机切换非线性系统的P阶矩稳定性与几乎必然稳定性.采用LyapunovRazumikhin方法和随机分析技术,建立了中立型随机切换非线性系统稳定性的判别准则,给出了中立型随机切换非线性系统稳定的充分条件.最后通过仿真算例表明了所得结果的有效性.     

具滞后超中立型定常线性大系统的指数稳定性

采用具有加权向量范数型Lyapunov函数，对具滞后超中立型线性大系统进行模型集结，得到集结系统；再运用原理与时域中的微分积分不等式，讨论相应集结系统，通过集结系统的稳定性，获得了具滞后超中立型大系统的指数稳定性．     

Hierarchical Liapunov functions

A complex system is considered as a collection of dynamic components which may be combined in different ways to form stable subassemblies (subsystems), which may serve again as units to build still more complex stable configurations. A hierarchical Liapunov function is proposed, which can be used to determine stability of the overall system obtained by the multilevel interconnection process. Stability when established in this way is hierarchically connective. That is, if at any instant in time, the hierarchical evolution of the system is interrupted, the system can fall apart in exactly the same way it was constructed and, by re-starting the process, put together again without loss of stability. This fact may be used to explain the evolution of stable forms in natural as well as man-made systems.     

Stability conditions for a pipeline polling scheme in satellite communications

This paper considers the unknown stability conditions of a pipeline polling scheme proposed for satellite communications. This scheme is modelled as a cyclic-service system with limited service and reservation. The walk times and the maximum number of services to be performed during each polling are dependent on the queue lengths of the stations. The main result is the derivation of the necessary and sufficient stability conditions of the system. Our approach is to map the multi-dimensional stability problem into many 1-dimensional stability problems through the concept of the least stable queue. The least stable queue is one that will become unstablefirst when the system load increases in some parameter region. The stability of the least stable queue thus implies stability of the system. The stability region for the whole system is then the union of the queue stability regions of all the least stable queues that are obtained through dominant systems and Loynes' theorem. We also propose a computable sufficient condition that is tighter than the existing result and present some numerical results.     

The evolution of invariant manifolds in Hamiltonian-Hopf bifurcations

We consider the evolution of the stable and unstable manifolds of an equilibrium point of a Hamiltonian system of two degrees of freedom which depends on a parameter, ν. The eigenvalues of the linearized system are complex for ν<0 and pure imaginary for ν>0. Thus, for ν<0 the equilibrium has a two-dimensional stable manifold and a two-dimensional unstable manifold, but for ν>0 these stable and unstable manifolds are gone. If the sign of a certain term in the normal form is positive then for small negative ν the stable and unstable manifolds of the system are either identical or must have transverse intersection. Thus, either the system is totally degenerate or the system admits a suspended Smale horseshoe as an invariant set.     

Hopf-pitchfork bifurcation and periodic phenomena in nonlinear financial system with delay

In this paper, we identify the critical point for a Hopf-pitchfork bifurcation in a nonlinear financial system with delay, and derive the normal form up to third order with their unfolding in original system parameters near the bifurcation point by normal form method and center manifold theory. Furthermore, we analyze its local dynamical behaviors, and show the coexistence of a pair of stable periodic solutions. We also show that there coexist a pair of stable small-amplitude periodic solutions and a pair of stable large-amplitude periodic solutions for different initial values. Finally, we give the bifurcation diagram with numerical illustration, showing that the pair of stable small-amplitude periodic solutions can also exist in a large region of unfolding parameters, and the financial system with delay can exhibit chaos via period-doubling bifurcations as the unfolding parameter values are far away from the critical point of the Hopf-pitchfork bifurcation.     

Reduction of linear systems to a form with relative degree using minimum-phase output transformation

A normal form is one of the canonical forms frequently used in control theory for linear time-invariant systems. Only systems with a relative degree can be reduced to such a form. Although a control system does not necessarily have a relative degree, in a sufficiently general case there exists a stable dynamic output transformation reducing the system to a system with a relative degree. We prove that this dynamic transformation can be chosen in such a way that the inverse transformation is stable as well.     

Numerical stability of a method for transferring boundary conditions

It is proved that a previously proposed method for transferring boundary conditions as applied to a boundary value problem for a linear system of ordinary differential equations gives numerically stable results if this problem is stable with respect to small variations in the input data.     

Stable projective planes with Riemannian metrics

We consider the question whether the system of lines of a two-dimensional stable plane can be described as the system of geodesics of a Riemannian metric and vice versa; we present two results: A complete two-dimensional Riemannian manifold with the property that every two points are joined by a unique geodesic and its family of geodesics form a stable plane. On the other hand every stable projective plane whose lines are geodesics of a Riemannian metric is isometric to the real projective plane. Combining both results it follows that it is impossible to realize the lines of a non-desarguesian projective plane using the geodesics of a complete Riemannian manifold.     

Feedback stabilization of a marginally stable parabolic equation and a counterexample to a conjecture on this topic

The first part of this paper is concerned with the exponential stabilization of certain marginally stable equations by means of a feedback. If you think of the standard Neumann problem for the Laplacian as an example of a marginally stable equation, there is the conjecture that for feedbacks with restricted sign the feedback system is always exponentially stable. We disprove this conjecture in the second part of our paper     

Some minimal bimolecular mass-action systems with limit cycles

We discuss three examples of bimolecular mass-action systems with three species, due to Feinberg, Berner, Heinrich, and Wilhelm. Each system has a unique positive equilibrium which is unstable for certain rate constants and then exhibits stable limit cycles, but no chaotic behaviour. For some rate constants in the Feinberg–Berner system, a stable equilibrium, an unstabe limit cycle, and a stable limit cycle coexist. All three networks are minimal in some sense.By way of homogenising these three examples, we construct bimolecular mass-conserving mass-action systems with four species that admit a stable limit cycle. The homogenised Feinberg–Berner system and the homogenised Wilhelm–Heinrich system admit the coexistence of a stable equilibrium, an unstable limit cycle, and a stable limit cycle.     

Stabilization of nonlinear systems with a dither control

In this paper a new approach is taken to analyze stabilization of a general nonlinear system with a dither input. Given the original system with a control, an autonomous relaxed system is constructed. It is shown that if the relaxed system is stable, then the original system with dither control would be stable in the finite time. An algorithm is given for constructing the dither control. The technique used here is general and does not have the limitations of the Dual Input Describing Function technique. Furthermore, in many cases it is possible to guarantee global contractive stability as well. Two examples are solved in detail using computer simulations for demonstration of the technique.