Stability and control of nonlinear systems described by retarded functional equations: a review of recent results

This paper reports on recent results in a series of the work of the authors on the stability and nonlinear control for general dynamical systems described by retarded functional differential and difference equations. Both internal and external stability properties are studied. The corresponding Lyapunov and Razuminkhin characterizations for input-to-state and input-to-output stabilities are proposed. Necessary and sufficient Lyapunov-like conditions are derived for robust nonlinear stabilization. In particular, an explicit controller design procedure is developed for a new class of nonlinear time-delay systems. Lastly, sufficient assumptions, including a small-gain condition, are presented for guaranteeing the input-to-output stability of coupled systems comprised of retarded functional differential and difference equations.     

Polarization discrimination between repeater false-target and radar target

High fidelity repeater false-target badly affects a radar system’s detecting, tracking, and data processing. It is an available approach of confronting false-target for radar that discriminates firstly and then eliminates. Whereas for the technique progress about the repeater false-target jam, it is more and more difficult to discriminate this jam in the time-domain, frequency-domain, or space-domain. The technique using polarization information to discriminate the target and false-target is discussed in th...     

遗传算法与文本特征选择方法相结合的研究

对文本特征选择的传统方法进行了深入分析并对各自的优缺点进行了详细的对比;其次,通过利用遗传算法自身的寻优特点,把它与传统特征选择方法相结合,并得出了算法。最后,在对各自算法进行了分析,表明了在性能上有了明显的提高。     

Peterson算法在场消隐期传输中的应用

场消隐期作为应用电视有限资源的一部分,其开发潜力正逐渐为人们所重视.本文提出了一种新型的综合数据传输业务的单缆传输电视监控系统,将控制信号搭栽在视频信号通道上运行,并以Peterson算法和Chien氏搜索法为基础,将无线通信中常用的(15,7)BCH控制编码应用于底层的单片机级的信号传输中,同时给出了相应的软件解码方法,在优化控制信号的传输线路和解决时延问题的同时,大大提高了实时数据通信的有效性和可靠性,从而达到了利用电视信号逆程资源的目的.     

基于Hyper Mesh的商用车驱动桥壳有限元分析

驱动桥壳是汽车的重要部件之一,应具有足够的强度和刚度。先利用UG建立桥壳的几何模型,然后在Hyper Mesh中进行网格划分、加载和约束,对驱动桥壳进行有限元分析计算,最后提出改进方案。     

Optimal hole shape for minimum stress concentration using parameterized geometry models

The goal of this work is to obtain optimal hole shape for minimum stress concentration in two-dimensional finite plates using parameterized geometry models. The boundary shape for a hole is described by two families of smooth curves: one is a “generalized circular” function with powers as two parameters; the other one is a “generalized elliptic” function a and b are ellipse axes) with powers as two parameters and one of the ellipse axes as the third parameter. Special attention is devoted to the practicability of parameterized equations and the corresponding optimal results under the condition with and without the curvature radius constraint. A number of cases were examined to test the effectiveness of the parameterized equations. The numerical examples show that extremely good results can be obtained under the conditions with and without curvature radius constraint, as compared to the known solutions in the literature. The geometries of the optimized holes are presented in a form of compact parametric functions, which are suitable for use and test by designers. It is anticipated that the implementation of the suggested parameterized equations would lead to considerable improvements in optimizing hole shape with high quality.     

Ubiquitous Personal Study: a framework for supporting information access and sharing

The information resources on the Web are diversified, the amount of which is increasing rapidly. Demands for selecting useful information from the Internet, managing personal contents, and sharing contents under control have risen. In this study, we propose the Ubiquitous Personal Study, a framework of personalized virtual study to support accessing, managing, organizing, sharing and recommending information. In this paper, we focus on discussing the framework, and design and implementation issues on how to implement it with Web 2.0 mash-up technology and Open Source Software.     

禅之韵——试谈卫浴空间的意境营造

禅是一种心灵体验,禅意的营造需要主人积极的情感投入。卫浴间是现代居室的重要组成部分,也是现代人放松身体的重要场所.本文试从卫浴产品的选择、空间的布局以及装饰三个方面展开讨论,对禅风的现实意义进行了反思。     

Control of frictional dynamics of a one-dimensional particle array

Control of frictional forces is required in many applications of tribology. While the problem is approached by chemical means traditionally, a recent approach was proposed to control the system mechanically to tune frictional responses. We design feedback control laws for a one-dimensional particle array sliding on a surface subject to friction. The Frenkel-Kontorova model describing the dynamics is a nonlinear interconnected system and the accessible control elements are average quantities only. We prove local stability of equilibrium points of the un-controlled system in the presence of linear and nonlinear particle interactions, respectively. We then formulate a tracking control problem, whose control objective is for the average system to reach a designated targeted velocity using accessible elements. Sufficient stabilization conditions are explicitly derived for the closed-loop error systems using the Lyapunov theory based methods. Simulation results show satisfactory performances. The results can be applied to other physical systems whose dynamics is described by the Frenkel-Kontorova model.     

AutoCAD的尺寸驱动技术的探讨

AutoCAD是一种人机交互的绘图软件,本身并不具备参数化绘图功能,更不具备尺寸驱动功能,但用户可以利用其所提供的强大的二次开发语言AutoLISP、VisualLISP、VBA开发完全个性化的、性能更为优越的、具有尺寸驱动功能的参数化绘图软件。