含时变时滞函数的GM(1,1|τ_i)模型及其应用

针对带有时滞效应的小样本数据序列的预测建模问题,现有模型通常假设时滞期为固定值,忽略了时滞值动态变化对模型效果的影响.为了克服这一局限性,本文考虑系统时滞的动态变化效应,将GM(1,1|τ,r)模型的静态时滞参数推广为时变时滞函数,设计出非整数时滞取值区间对应的时变时滞参数表达式.提出以灰关联理论为基础的时变时滞函数的参数优化方法,推导出GM(1,1|τ_i)模型参数估计值以及预测序列的时间响应式.该方法不仅提高了模型对所分析序列的拟合度,还可充分利用时滞参数函数的数学性质,进一步研究时滞因素对系统发展趋势的影响.最后,将GM(1,1|τ_i)模型应用于福建省全省沿海港口货物吞吐量预测,并将建模预测结果与经典的GM(1,1)模型和GM(1,1,τ)模型进行比较.结果表明当原始序列具有时滞效应时,GM(1,1|τ_i)模型具有更高的建模精度,能够反映出更为复杂的系统时滞变化情况,扩展了含时滞参数灰色预测模型的适用范围.     

General Decay Synchronization for Recurrent Neural Networks with Mixed Time Delays

This paper studies the general decay synchronization(GDS) of a class of recurrent neural networks(RNNs) with general activation functions and mixed time delays. By constructing suitable Lyapunov-Krasovskii functionals and employing useful inequality techniques, some sufficient conditions on the GDS of considered RNNs are established via a type of nonlinear control. In addition, one example with numerical simulations is presented to illustrate the obtained theoretical results.     

基于本地品牌生产外包考虑的跨国公司竞争及转移定价策略研究

转移定价(transfer pricing)是跨国公司进行内部关联交易时的重要决策之一,同时对提升公司全球税后利润也有重要作用.本文在考虑跨国公司利用转移定价进行全球税收筹划基础上,考察实践中观察到的一个现象,即跨国公司不仅通过生产满足其全球需求,还满足本地竞争品牌的需求.假设转移定价具有事前特征,本研究以最大化全球税后利润为目标,分析跨国公司和本地品牌参与最终市场竞争并伴随着生产阶段合作的情形.结果显示,价格低廉不是本地品牌进行生产外包决策的适用准则.另一方面,垄断本地市场也非跨国公司的目标.在该结果基础上,文章对考虑本地品牌生产外包情况下,跨国公司参与本地竞争及全球税后利润优化的动机进行了解释.     

Global input-to-state stabilization with quantized feedback for discrete-time piecewise affine systems with time delays

In this paper, global input-to-state stabilization with quantized feedback for discrete-time piecewise affine systems （PWA） with time delays are considered. Both feedback with time delays and feedback without time delays are considered. Piecewise quadratic ISS-Lyapunov functions are adopted. Both Lyapunov-Razumikhin and Lyapunov-Krasovskii methods are adopted. The theorems for global input-to-state stabilization with quantized feedback of discrete PWA systems with time delays are     

基于改进Smith预估补偿的网络控制系统研究

为了有效减少网络时延对网络控制系统的影响,提出了一种新的改进Smith动态预估补偿方法,实现了将前向通路的时延从闭环回路中移到闭环回路外,将反馈通路(传感器到控制器)的时延从系统中彻底消除,无需对反馈通路实施网络调度。由于补偿模型不包含网络时延,因此无需在线测量、辨识或估计网络时延的大小,适用于网络时延是随机、时变和不确定,大于一个、甚至数十个采样周期的应用场合。基于CSMA/CD(Ethernet)和CSMA/AMP(CAN bus)网络协议,仿真研究验证了该方法的有效性。     

Adaptive output-feedback control for MIMO nonlinear systems with time-varying delays using neural networks

An adaptive neural network output-feedback regulation approach is proposed for a class of multi-input-multi-output nonlinear time-varying delayed systems. Both the designed observer and controller are free from time delays. Different from the existing results, this paper need not the assumption that the upper bounding functions of time-delay terms are known, and only a neural network is employed to compensate for all the upper bounding functions of time-delay terms, so the designed controller procedure is more simplified. In addition, the resulting closed-loop system is proved to be semi-globally ultimately uniformly bounded, and the output regulation error converges to a small residual set around the origin. Two simulation examples are provided to verify the effectiveness of control scheme.     

QUEUEING NETWORK MODELING AND ANALYSIS IN THE DESIGN AND EVALUATION OF SEAPORT SYSTEMS

1.IntroductionDlletothecapacityconstraintsacttiledeepwaterPiel.s,1llztllyI)ortsarefacinglongdelaysoftilea,rrivingstealllsllil)sarrivingfyolntilePad(~ifi(.oceitll.Ashot,e(lillYlle,etal.[1].ifports}'stellllllllst,l)eplannedtosatisfybotllill(>steamshipcolnpa…     

具有时滞的二阶Hopfield神经网络的稳定性分析

对具有时滞的二阶Hopfield型神经网络平衡点的全局渐近稳定性问题进行了研究。在不要求连接权矩阵的对称性和输入输出函数的可微性与单调性的情况下 ,通过构造适当的Lyapunov泛函得到了网络平衡点的存在性和全局渐近稳定性的若干充分条件 ,这些条件可用于设计全局渐近稳定的二阶人工神经网络。     

一类时滞免疫反应系统动力学行为仿真

研究一类时滞免疫反应系统在机体清除靶细胞能力对浆细胞增长有影响的情形下的动力学行为,用时滞微分理论证明系统正平衡点的稳定性与时滞的关系,给出其稳定判定方法。在模型解基础上,用仿真方法研究部分参数变化对系统动力学行为的影响,给出了免疫系统呈现不同动力学行为的参数范围,实现免疫系统动态特性的仿真。结果表明,对于给定时滞,免疫反应系统的动力学行为不敏感地依赖于抗体清除抗原速率,而敏感地依赖于抗原繁殖系数。     

时延优化的多信道MMSE均衡

无线通信系统中的接收机通过分数采样得到一个单输入多输出的多信道模型。研究了此多信道系统的均衡问题，给出了基于最小均方误差的多信道均衡器结构，其中每个子信道都对应一个最佳时延参数，理论分析给出了此最佳时延的一个较窄的取值范围。仿真与分析表明，在此范围内，各子信道时延取为子信道阶数加一时，系统性能并没有大的损失，可以接受，同时在这种情况下均衡器的实现结构大为简化。     

基于广义动态灰关联度窗口的时滞分析模型

基于静态最大关联度准则的经典灰关联时滞分析方法对样本时序的依赖性较强,分析结论的代表性较差、甚至会出现自相矛盾的地方.为此,本文探讨了一种新的全局性动态时滞分析方法.首先,设计了新信息优先加权算子,将其引入广义灰色关联度模型,强调新信息在关联分析中的重要性.其次,针对经典的基于灰关联度的时滞分析方法的不足,提出动态灰关联度窗口的概念,对样本时序中所有潜在时滞取值展开系统化的分析.再者,定义了基于动态灰关联度窗口概念的时滞关联度矩阵以及相应的时滞灰关联度向量,设计出灰栈矩阵这一特殊灰关联数据存储结构,动态对比所有潜在时滞关系,找出代表性时滞值.最后,对宏观经济指标之间的时滞关系展开案例分析,并与经典灰关联时滞分析方法进行对比,结果表明本文设计的时滞分析方法具有更好的说服力.     

基于观测器的CAN网络在线时延补偿策略

网络时延问题是网络控制系统中的主要问题。为了解决网络时延给控制系统带来影响的问题,首先分析网络时延的产生及其可能的取值特性,在网络时延统计特性信息的基础上,从通信技术和控制技术相结合的角度出发,提出了一种基于观测器的在线时延补偿方法。通过CAN bus网络控制实验平台,分析了该补偿方法的有效性。实验结果表明,在网络延迟大的控制系统中该策略仍具有良好的控制效果。     

Global Dynamics for an HIV Infection Model with Crowley-Martin Functional Response and Two Distributed Delays

In this paper, an HIV dynamics model with two distributed intracellular delays incorporating Crowley-Martin functional response infection rate is investigated. The authors take into account multiple stage disease transmission and the latently infected cells (not yet producing virus) in our system. The authors consider nonnegativity, boundedness of solutions, and global asymptotic stability of the system. By constructing suitable Lyapunov functionals and using the Lyapunov-LaSalle invariance principle, the authors prove the global stability of the infected (endemic) equilibrium and the diseasefree equilibrium for time delays. The authors have proven that if the basic reproduction number R₀ is less than unity, then the disease-free equilibrium is globally asymptotically stable, and if R₀ is greater than unity, then the infected equilibrium is globally asymptotically stable. The results obtained show that the global dynamic behaviors of the model are completely determined by the basic reproduction number R₀ and that the time delay does not affect the global asymptotic properties of the model.     

UNIFORM PERSISTENCE AND GLOBAL ATTRACTIVITY FOR NONAUTONOMOUS COMPETITIVE SYSTEMS WITH DISPERSION

In this paper, we consider a nonautonomous competitive model with dispersion and a finite number of discrete delays. The system, which consists of two Lotka-Volterra patches, has two competitors: one can disperse between the two patches, but the other is confined to one patch and cannot disperse. Our purpose is to demonstrate that the dispersion rates have no effect on the uniform persistence of the solutions of the system. Furthermore, we establish the conditions under which the system admits a positive periodic solution which attracts all solutions.     

On the exponential stability of neural networks systems with time-varying delay

In this paper, exponential stability of Hopfield-type neural networks with time-varying delays are analyzed. By using the Lyapunov functional method, sufficient conditions are obtained for general exponential stabilities. At the same time, the output functions do not satisfy the Lipschitz conditions and do not require them to be differential or strictly monotonously increasing. Moreover, all results are established without assuming any symmetry of the connection matrix.A numeric example is pressented to show the effective of these criteria.     

不确定模糊时滞系统的鲁棒H∞滤波

研究了一类带有时滞的不确定离散时间模糊系统的鲁棒H∞滤波问题。模糊H∞滤波器的设计建立在T-S模糊模型上并能确保滤波误差系统的渐近稳定和给定的H∞性能指标。考虑了时滞的存在使得滤波器有更小的保守性,由线性矩阵不等式（LMI）给出滤波器存在的充分条件。最后,仿真算例验证了给出方法的有效性。     

Analyses of location-price game on networks with stochastic customer behavior and its heuristic algorithm

<正> In this paper,a two-stage model is developed to investigate the location strategy andthe commodity pricing strategy for a retail firm that wants to enter a spatial market with multiplecompetitive facilities,where a competitor firm is already operating as a monopoly with several outlets.Expected market shares are calculated based on the stochastic customer behavior on networks.Theauthors provide a sufficient condition for the existence of equilibrium prices in the price game for thefirst time.The existence and uniqueness of the pure strategy Nash equilibrium price with a specifiedutility function are proved in the subgame.A metaheuristic based on tabu search is proposed tosearch the optimal location-price solution of the model.In addition,the authors provide two numericalexamples to illustrate how to obtain the optimal solution and conduct sensitivity analysis.The analysisshows that the best location decision is robust for the follower firm,price game is more intense whenincomes of consumers are lower or there are more substitution products,and neither chain retail gainsfrom the price competition.     

Finite-Time and Fixed-Time Synchronization of Inertial Neural Networks with Mixed Delays

This paper considers the drive-response synchronization in finite-time and fixed-time of inertial neural networks with time-varying and distributed delays(mixed delays). First, by constructing a proper variable substitution, the original inertial neural networks can be rewritten as a first-order differential system. Second, by constructing Lyapunov functions and using differential inequalities,some new and effective criteria are obtained for ensuring the finite-time synchronization. Finally, three numerical examples are also given at the end of this paper to show the effectiveness of the results.     

Online Delay-Evaluation Approach in Networked Control Systems

This paper presents an online evaluation approach of time delays for networked control systems (NCS), which characterizes the time delays without any synchronized clock in the network and any assumptions of time delays. With this approach, an optimal control scheme based on the approach is designed to achieve the desired performance despite the uncertain delays in the system. The experimental results based on CANbus illustrate the effectiveness of the proposed control design and satisfactory performance of the closed-loop system.     

Controlling uncertain fuzzy neutral dynamic systems with Markov jumps

The robust H∞ control problems for stochastic fuzzy neutral Markov jump systems (MJSs) with parameters uncertainties and multiple time-delays are considered. The delays are respectively considered as constant and time varying, and the uncertain parameters are assumed to be norm bounded. By means of Takagi-Sugeno fuzzy models, the overall closed-loop fuzzy dynamics are constructed through selected membership functions. By selecting the appropriate Lyapunov-Krasovskii functions, the sufficient condition is given such that the uncertain fuzzy neutral MJSs are stochastically stability for all admissible uncertainties and satisfies the given H∞ control index. The stability and H∞ control criteria are formulated in the form of linear matrix inequalities, which can be easily checked in practice. Practical examples illustrate the effectiveness of the developed techniques.