带不确定动态输入非线性系统的鲁棒几乎干扰解耦

研究一类带不确定输入动态非线性系统的几乎干扰解耦问题 .利用反传设计方法构造了鲁棒状态反馈控制器 ,使得对所有可允许的不确定输入动态 ,闭环系统在零初始状态下从干扰到输出的L2 增益任意小 ,同时在干扰输入恒为零时闭环系统是全局渐近稳定的     

可理解性输入理论应用于大学英语新闻听力教学

英语新闻提供了最前沿的信息及相关词汇，听英语新闻是训练听力、扩大词汇的最好手段，但大多数学生因各种原因放弃了新闻学习。克拉申在20世纪70年代末提出可理解性语言输入，对外语教学产生了深远的影响，对听力教学有一定的指导作用，对大学英语新闻听力也有很强的借鉴作用，这种输入方式可以有效地加快学习进程，教师可根据其规律对学生进行指导，培养学生听新闻的习惯，树立学生学习的信心，从而提高学习英语的兴趣，提高英语听说水平。     

On stability of discrete-time switched systems

This article deals with stability of discrete-time switched systems. Given a family of nonlinear systems and the admissible switches among the systems in the family, we first propose a class of switching signals under which the resulting switched system is globally asymptotically stable. We allow unstable systems in the family and our stability condition depends solely on asymptotic behaviour of the switching signals. We then discuss algorithmic construction of the above class of switching signals, and show that in the presence of exogenous inputs and outputs, a switching signal so constructed also ensures input/output-to-state stability for discrete-time switched nonlinear systems. We finally show that our class of switching signals that ensures global asymptotic stability also extends to the continuous-time setting with minor modifications under standard assumptions. We employ multiple Lyapunov-like functions and graph theoretic tools as the main apparatuses for our analysis.     

投入产出分析中直接消耗系数和完全消耗系数的关系探讨

在投入产出分析中,投入产出系数是根据企业的特点,运用人力资源会计的方法,建立起来以投入、产出及其比值为主要指标的模型。投入产出系数对于分析各部门投入产关系有着重要的作用。投入产出系数有很多,但是它们在投入产出分析中有着不同的作用。直接消耗系数、完全消耗系数是投入产出分析中核心的两个系数。这两个系数在某种程度上存在着联系但又有所区别。本文主要浅析了直接消耗系数和间接消耗系数之间的区别与关系。     

Asymptotical properties of erlang queueing systems with a dependent Poisson input flow

The purpose of this paper is to obtain stationary characteristics of the mathematical model, which consists of two Erlang queueing systems with a bivariate Poisson input flow of customers. Functional theorems of diffusion approximation type are proved. This paper is supported by INTAS 96-0828.     

区域水环境经济系统优化模型及其应用

基于改进的经济、环境、资源、污染治理投入产出模型,建立了区域水环境经济多目标优化规划模型。该模型以宏观经济子模型及其它子模型为基础,以多目标优化规划模型为核心,并在多目标分析模型中集系统要素为一体,具有预测、模拟、优化及决策分析等功能。以关中地区为例讨论了其应用,结果表明该模型能较好地协调经济与环境的关系,为水环境与经济的可持续发展提供了一种可操作的方法。     

综合经济数学模型

本文从资源约束、预算约束和需求约束入手,建立综合经济竞争均衡的一个数学模型,并应用不动点定理证明了这种均衡的一个存在性定理.     

Competition for limited critical resources and the adoption of environmentally sustainable strategies

We develop a game-theoretical methodology that incorporates competition for limited resources to explicitly model a firm's valuation and, hence, its decision whether to adopt environmentally sustainable strategies (e.g., recycling programs to replace limited natural resources, alternative technologies). Even if switching to environmentally sustainable alternatives proves too expensive for individual firms, or resource costs are expected to remain low, we show that competition for resources would still push firms to incur switching costs as they become more environmentally sustainable. Using a sample of firm-level data from the KLD database which includes firms' sustainability policies, we find empirical support that competition for resources is positively correlated with a firm's adoption of environmental strategies. Tests that use the Chinese government's 2010 rare-earth supply suspension as an exogenous shock to competition for limited resources suggest a causal interpretation for our finding.     

基于Flash的藏文字母打字游戏的设计与实现

目前各种教育游戏的使用越来越普遍,特别是层出不穷的打字游戏,使用户能够熟练掌握各种键盘输入技能,有效激发了用户学习文字的兴趣。文章设计了基于Flash的藏文字母打字游戏,实现了藏文字母的输入、判断、计时和成绩输出等功能,输入法采用微软的Himalaya藏文输入法。