Generalized random recursive constructions and geometric properties of random fractals

We study random recursive constructions in which the contracting vectors have different distributions at different stages. With such constructions, the one parameter family of martingales are introduced and the probabilistic behaviours of the limit random objects (not identically distributed) are discussed. We prove that the random fractal associated with such construction has a constant Hausdorff dimension almost surely and give an explicit formula to determine it. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Fixed period of temporary immunity after run of anti-malicious software on computer nodes

SIRS epidemic model has been developed with a fixed period of temporary immunity, following temporary recovery from the infection of malicious objects in place of an exponentially distributed period of temporary immunity. When a node is recovered from the infected class, it recovers temporarily, acquiring temporary immunity with probability p (0  p  1) and dies from the attack of malicious object with probability (1 − p). Temporary immunity is observed in the computer network when anti-malicious software is run after a node gets affected by a malicious object(s). The model consists of a set of integro-differential equations. The stability of the results is stated in terms of threshold parameter. It has been observed that the endemic equilibrium for this model may be unstable thus giving an example of a generalization which leads to new possibilities for the behavior of the model. Numerically it has been verified that the endemic equilibrium is not asymptotically stable for all parameter values.     

Boundary observability of elastic vibrations in a system of sequentially connected strings

The observability problem for the elastic vibrations of a system consisting of sequentially connected objects with distributed parameters is solved. An object with lumped parameters is connected to the system. The initial state of the system is recovered from observations on its boundary and at the connection point of the objects with distributed and lumped parameters.     

Reduced-order feedback control of distributed parameter systems via singular perturbation methods

Implementable feedback control of distributed parameter systems must often be based on reduced-order models due to the infinite dimensional nature of the actual open-loop system. The behavior of controllers designed via reduced-order models obtained with singular-perturbation techniques is analyzed. When such controllers are used in the actual distributed parameter system, the closed-loop stability is in question. The results presented here provide bounds on the smallness of the singular perturbation parameter to ensure stable operation; such a priori bounds may be used to evaluate potential reduced-order controllers for distributed parameter systems.     

广义算子半群与广义分布参数系统的适定性

首先,针对广义分布参数系统的求解问题,提出了由Hilbert空间中有界线性算子所引导的广义算子半群和广义积分半群;其次,讨论了广义预解算子的性质、广义算子半群与广义积分半群的性质;最后,研究了广义分布参数系统的适定性问题.     

广义分布参数系统的状态反馈稳定性问题(1)

关于系统的状态反馈稳定性问题的研究一直是现代控制理论研究的重要问题之一.广义分布参数系统是比分布参数系统更广的一类系统,在研究复合材料热导体中的温度分布等问题时会出现这样的系统.本文讨论了H ilbert空间中一阶广义分布参数系统的状态反馈稳定性问题.应用泛函分析及线性算子半群理论的方法给出了使闭环广义分布参数系统渐进稳定的充要条件,充分条件及状态反馈的构造性表达式.这对研究广义分布参数系统的状态反馈稳定性问题具有重要的理论价值.     

Stability of distributed parameter systems with finite-dimensional controller-compensators using singular perturbations

Using a singular perturbation formulation of the linear time-invariant distributed parameter system, we develop a method to design finite-dimensional feedback compensators of any fixed order which will stabilize the infinite-dimensional distributed parameter system. The synthesis conditions are given entirely in terms of a finite-dimensional reduced-order model; the stability results depend on an infinite-dimensional version of the Klimushchev-Krasovskii lemma presented here.     

State observability of elastic vibrations in distributed and lumped parameter systems

State observation problems for the vibrations in a distributed and lumped parameter system are solved. The vibrations of the distributed parameter object are described by boundary value problems with Dirichlet boundary conditions, while the lumped parameter object is described by a secondorder ordinary differential equation.     

Efficient estimation of a varying-coefficient partially linear binary regression model

This article considers a semiparametric varying-coefficient partially linear binary regression model. The semiparametric varying-coefficient partially linear regression binary model which is a generalization of binary regression model and varying-coefficient regression model that allows one to explore the possibly nonlinear effect of a certain covariate on the response variable. A Sieve maximum likelihood estimation method is proposed and the asymptotic properties of the proposed estimators are discussed. One of our main objects is to estimate nonparametric component and the unknowen parameters simultaneously. It is easier to compute, and the required computation burden is much less than that of the existing two-stage estimation method. Under some mild conditions, the estimators are shown to be strongly consistent. The convergence rate of the estimator for the unknown smooth function is obtained, and the estimator for the unknown parameter is shown to be asymptotically efficient and normally distributed. Simulation studies are carried out to investigate the performance of the proposed method.     

分布参数与集中参数耦合系统的极点配置问题

设 H 是可分的 Hilbert 空间,A 是空间 H 中的线性算子,b∈H 是非零元.考察空间H 中的一阶发展方程描述的控制系统(dx)/(dt)=Ax+bu(t),x(0)=x_0,(1)这里 u(t) 是控制量,是一数值函数.考察反馈控制律u(t)=〈x(t),g〉,(2)这里 g∈H 是非零元,〈·,·〉是 H 上的内积.     

物块落水后运动过程的动力学分析

采用动力学的方法,对物块在流场中的运动进行了受力分析,通过动力学微分方程和边界条件分别得到物体静止进入水中和运动进入水中的物体运动轨迹方程.对于复杂形状,通过工程中常用的体积等效和截面等效的方法获得当量直径,将物块等效为球形,并且引入了空心率的概念用于表征物块形状参数对流场中受力的影响.对于溃口封堵的真实流场,可以采用重力相似准则转化为模型适用的小型流场情况,对其进行分析.     

非线性时变广义分布参数系统的适定性问题

本文的主要目的是讨论非线性时变广义分布参数系统的适定性问题.首先,在Banach空间中引入由连续(可能是非线性的)算子引导的非线性广义发展算子,该非线性广义发展算子是广义发展算子的推广,并研究非线性广义发展算子的性质;然后,应用非线性广义发展算子讨论非线性时变广义分布参数系统的适定性问题,并给出解的构造性表达式.     

Two-end observability of elastic vibrations in distributed and lumped parameter systems

The boundary observation problems (initial state reconstruction) of vibrations in objects with distributed and lumped parameters are solved. The vibrations in an object with distributed parameters are described by boundary value problems with boundary conditions of various types. An object with lumped parameters is described by a second-order ordinary differential equation.     

二阶广义分布参数系统的谱分布

应用泛函分析算子理论的方法研究了Hilbert空间中二阶广义分布参数系统的谱分布问题,利用有界线性算子的广义逆给出了所讨论问题的解及解的构造性表达式。这对研究二阶广义分布参数系统的镇定及渐进稳定性问题都有重要的理论价值。     

Port-based approach to distributed transfer function method

In the paper there is presented an uniform, port-based approach to modeling of both lumped and distributed parameter systems. Port-based model of distributed system has been defined by application of distributed transfer function method (DTFM). The approach proposed combines versatility of port – based modeling and accuracy of distributed transfer function method. It enables to formulate appropriate input data for computer analysis by application of DTFM. The concise representation of lumped-distributed systems is obtained. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On uniform asymptotic normality of sequential least squares estimators for the parameters in a stable AR(p)

For a stable autoregressive process of order p with unknown vector parameter θ, it is shown that under a sequential sampling scheme with the stopping time defined by the trace of the observed Fisher information matrix, the least-squares estimator of θ is asymptotically normally distributed uniformly in θ belonging to any compact set in the parameter region.     

Compactness of a fixpoint set and optimal control

Solutions of the dynamic equations in distributed parameter systems are usually obtained as fixpoints of suitable maps, as in Picard iteration. In optimal control of distributed parameter systems, some compactness of the fixpoint set is then needed to extract a convergent minimizing sequence. Two results are obtained to show, when the family of maps is equicontractive, that one can extract such a sequence under suitable hypotheses.     

An extremal problem for Graham-Rothschild parameter words

This paper exposes connections between the theory of Möbius functions and extremal problems, extending ideas of Frankl and Pach [8]. Extremal results concerning the trace of objects in geometric lattices and Graham—Rothschild parameter posets are proved, covering previous results due to Sauer [16] and Perles and Shelah [17].     

均布荷载作用下压电材料简支梁的解析解

采用逆解法求解了均布荷载作用下压电材料简支梁的解析解。首先给出应力函数和电位移函数的多项式表达式,进而根据相容方程以及应力和电位移、位移和电势的边界条件,求得了同时考虑材料弹性参数、密度参数和压电参数呈梯度变化时,简支梁在均布荷载作用下的解析解。作为特例还得到了常体力以及材料参数为常数时的解答。并对结果进行了讨论。     

A Generating Tree Approach to <Emphasis Type="Italic">k</Emphasis>-Nonnesting Partitions and Permutations

We describe a generating tree approach to the enumeration and exhaustive generation of k-nonnesting set partitions and permutations. Unlike previous work in the literature which uses the connections of these objects to Young tableaux and restricted lattice walks, our approach deals directly with partition and permutation diagrams. We provide explicit functional equations for the generating functions, with k as a parameter. Key to the solution is a superset of diagrams that permit semi-arcs. Many of the resulting counting sequences also count other well-known objects, such as Baxter permutations, and Young tableaux of bounded height.