Cucker–Smale flocking under rooted leadership and time-varying heterogeneous delays

In this paper, a Cucker–Smale model with time-varying heterogeneous delays in the communication process is investigated, where the delay on each communication link is time-varying and independent of other communication links. A general update rule based on the distance between agents is used to determine the edge weights of the communication network. The method of constructing augmented system is used so that the system stability is transformed into a product convergence problem of time-varying sub-stochastic matrices equivalently. By analyzing this convergence problem, a sufficient condition is established to achieve flocking, which relates to the initial states, the structure of communication network and the upper bound of time delays.     

若干类时滞切换系统的稳定性问题

主要研究了镇定切换系统的鲁棒稳定性问题.用切换lyapunov函数方法,通过定义指标函数,讨论了基于切换lyapunov函数的若干类时滞切换系统的稳定性问题,用矩阵不等式研究了时滞,时滞摄动和不确定时滞的切换系统的鲁棒稳定性.     

分布时滞系统的动态输出反馈鲁棒稳定

主要研究了一类具分布时变时滞不确定系统的输出反馈鲁棒稳定问题.基于动态输出反馈和Lyapunov-Krasovskii泛函,给出了闭环系统与时滞相关的鲁棒稳定的条件.所得条件为线性矩阵不等式形式,便于运用内点算法进行求解.     

Minimum time problem for distributed hyperbolic systems with time lags

In this paper the time-optimal control problem for distributedhyperbolic systems in which constant lags appear both in thestate equations and in the boundary conditions is considered.The particular properties of the optimal control are discussed.     

具变时滞的细胞神经网络的周期解

本文研究了一类具变时滞细胞神经网络系统,利用重合度理论中的延拓定理、不等式的分析原理、矩阵理论和Lyapunov泛函方法,得到了该系统周期解的存在唯一性及全局指数稳定性的结论,不仅在一些应用领域上是可行的且易检验,而且为神经网络系统周期解的存在性论证,提供了一个新的有效方法.     

The standard regulator problem for systems with input delays. An approach through singular control theory

We present a new solution to the quadratic regulator problem for systems with input delays. Our approach makes use of the existing theory of the singular quadratic regulator problem for distributed systems.This paper was written with the financial support of the Italian Ministero della Ricerca Scientifica e Tecnologica within the program of GNAFA-CNR.     

A Comparison of Stochastic Systems with Different Types of Delays

In this article, we investigate the effects of different types of delays, a fixed delay and a random delay, on the dynamics of stochastic systems as well as their relationship with each other in the context of a just-in-time network model. The specific example on which we focus is a pork production network model. We numerically explore the corresponding deterministic approximations for the stochastic systems with these two different types of delays. Numerical results reveal that the agreement of stochastic systems with fixed and random delays depend on the population size and the variance of the random delay, even when the mean value of the random delay is chosen the same as the value of the fixed delay. When the variance of the random delay is sufficiently small, the histograms of state solutions to the stochastic system with a random delay are similar to those of the stochastic model with a fixed delay regardless of the population size. We also compared the stochastic system with a Gamma distributed random delay to the stochastic system constructed based on the Kurtz's limit theorem from a system of deterministic delay differential equations with a Gamma distributed delay. We found that with the same population size the histogram plots for the solution to the second system appear more dispersed than the corresponding ones obtained for the first case. In addition, we found that there is more agreement between the histograms of these two stochastic systems as the variance of the Gamma distributed random delay decreases.     

Stability and bifurcation analysis in a system of four coupled neurons with multiple delays

A system of delay differential equations is studied which represent a model for four neurons with time delayed connections between the neurons and time delayed feedback from each neuron to itself. The linear stability and bifurcation of the system are studied in a parameter space consisting of the sum of the time delays between the elements and the product of the strengths of the connections between the elements. Meanwhile, the bifurcation set are drawn in the parameter space.     

Multiple periodic solutions in impulsive hybrid neural networks with delays

The existence of multiple periodic solutions and their exponential stability are investigated for impulsive hybrid Hopfield-type neural networks with both time-dependent and distributed delays, using the Leray-Schauder fixed point theorem and Lyapunov functionals. The criteria given are easily verifiable, possess many adjustable parameters, and depend on impulses, providing flexibility for the analysis and design of delayed neural networks with impulse effects. Examples are given.     

脉冲时滞细胞神经网络的周期解的存在性

利用重合度理论中的延拓定理和微分不等式技巧,给出了具有状态依赖时滞和分布时滞的脉冲细胞神经网络的周期解的存在性的充分条件.     

Stability of Hopfield-type neural networks II

The global asympatotic stability and asymptotic stability for Hopfield-type neural networks with delays are investigated. Project supported by the National Natural Science Foundation of China.     

Attractors for the multilayer quasi-geostrophic equations of the ocean with delays

In this article, we study the multilayer quasi-geostrophic equations of the ocean with delays. We prove the existence of an attractor using the theory of pullback attractors.     

一类具有多时滞的差分系统的振动准则

研究了如下时滞差分系统Δxj(n)+∑li=1∑mr=1birj(n)xr(n-i)=0,j=1,2,…,m的振动性,给出了系统所有解振动的若干充分条件.     

SOME NEW RESULTS ON THE PERMANENCE OF A LOGISTIC TYPE SYSTEM WITH TIME DELAYS

In this paper, we study a class of Logistic type system with both discrete delays and continuous delays. Some new criteria on the permanence of the system are established. An example shows the feasibility of our main results.     

一类脉冲时滞宿主一大寄生物系统周期解及全局吸引性(英文)

By using Mawhin continuation theorem,an important lemma and some analysis techniques,sufficient conditions ensuring the existence and global attractivity of positive periodic solutions for an impulsive differential equation with time varying delay are investigated.     

具有多个变时滞的Lurie间接控制系统的绝对稳定性

本文利用M-矩阵性质,构造相应的Lyapunov函数,得到了具有多个变时 滞Lurie间接控制系统与时滞相关及与时滞无关绝对稳定的充分条件.文中的结论推 广和改进了已有文献中相应结果.     

Global asymptotic stability of stochastic Cohen-Grossberg-type BAM neural networks with mixed delays: An LMI approach

In this paper, we consider the stochastic Cohen-Grossberg-type BAM neural networks with mixed delays. By utilizing the Lyapunov-Krasovskii functional and the linear matrix inequality (LMI) approach, some sufficient LMI-based conditions are obtained to guarantee the global asymptotic stability of stochastic Cohen-Grossberg-type BAM neural networks with mixed delays. These conditions can be easily checked via the MATLAB LMI toolbox. Moreover, the obtained results extend and improve the earlier publications. Finally, a numerical example is provided to demonstrate the low conservatism and effectiveness of the proposed LMI conditions.     

一类多滞量周期扰动非线性系统的周期解

研究一类具有多个滞量的周期扰动非线性系统的T周期解.利用拓扑度的方法得到了系统存在T周期解的充分条件.作为应用,证明了具有滞后的单种群对数模型在一定条件下存在正周期解.     

Least-squares linear estimation of signals from observations with Markovian delays

The least-squares linear estimation of signals from randomly delayed measurements is addressed when the delay is modeled by a homogeneous Markov chain. To estimate the signal, recursive filtering and fixed-point smoothing algorithms are derived, using an innovation approach, assuming that the covariance functions of the processes involved in the observation equation are known. Recursive formulas for filtering and fixed-point smoothing error covariance matrices are obtained to measure the goodness of the proposed estimators.     

Relative controllability of perturbations of nonlinear systems

Sufficient conditions are derived for the relative controllability of perturbations of nonlinear systems with distributed delays in the control variables. The results are a generalization of previous results and are obtained by using Schauder's fixed-point theorem.