电路二等分问题的一个强化半定松驰模型

由于电路二等分问题在超大规模集成电路 (VLSI)设计中的基础地位 ,电路二等分半定松驰问题一直引人关注 .能否找到更好的半定规划模型 ,使其为电路二等分问题提供一个更好的下界 ,成为一个重要的研究方向 ;本文在已有半定规划松驰模型的基础上 ,通过增加非线性约束 ,得出电路二等分问题的等价模型 ,再利用提升技巧 ,得到一个强化半定规划松驰模型 .理论证明该模型给出了原有问题的一个更好的下界 ,数值实验也说明了这一点 .     

串并联电路的可靠性问题

随着科学技术的发展,串、并联电路在日常生活及生产中时常可见.下面我们用概率知识来研究串、并电路工作的可靠性问题. 一、简单串、并联电路正常工作的概率     

以“独立事件积的概率”为例浅析教材课后习题的使用

一、提出问题 笔者前不久在讲授沪教版高三拓展“独立事件积的概率”时,在习题册上遇到如下问题. 图1为M与N两点间的电路,在时间T内不同元件发生故障的事件是互相独立的,其发生故障的概率如表1所示. (1)求在时间丁内,K1与K2同时发生故障的概率; (2)求在时间T内,由于K1与K2发生故障而影响电路的概率; (3)求在时间T内,任一元件发生故障而影响电路的概率.     

强度调制型光纤静冰压力检测电路的设计

针对静冰压力检测的工程适用现状,设计了一种低功耗,全天侯自动检测系统.该系统基于反射式强度调制型光纤传感器,由光发射电路、光接收电路、AD转换电路、单片机电路以及数据存储电路等组成.对该光纤静冰压力的检测电路进行了实验测试,实验结果表明,检测系统电路可实现从作用于传感器压力敏感元件的微弱静冰压力变化到信号采集端的显著电压值变化及其自动检测.     

基于一种半间歇控制的忆阻超混沌电路的同步（英文）

就一种由蔡氏超混沌电路衍生而来的电路的基本特征进行了分析;并且就一种包含两种不同类型的子控制器的具有三明治结构的半间歇控制方法进行了研究与讨论.基于线性矩阵不等式(LMIs),李雅普诺夫稳定性理论以及本文中的半间歇控制方法,在实现两个忆阻(分段线性模型的忆阻器)超混沌电路的同步过程中的参数不匹配问题得以解决,并且还给出了实现这两个忆阻超混沌电路同步的指数稳定条件.最后的仿真实验还进一步验证了该方法的高效及可行性.     

以电路为背景的概率题的解题思路

近几年高考中时常中出现以电路为背景的概率习题,特别是在3+X高考模式,各学科相互交叉、渗透这种大背景下,这类题目引起了中学师生的广泛关注. 这类题目思路为:结合电路特点,转化为概率模型.具体解题步骤如下: 1)从电路图入手,观察电路特点,分清是串联电路、并联电路还是混合电路(混合电路最为常见),对于混合电路,可将其分割成几个电路单元.     

求多项式方程组的所有孤立解

解多项式方程组的根是相当有趣而且经常出现在应用科学上的问题。譬如说电路分配问题,机械手问题等等。同时这种问题也出现在浑沌理论的研究中。譬如说Lorenz最近介绍了一组有浑沌现象的四维常微分方程组     

GL算法在FM振荡器的稳健性参数设计中的应用

针对FM振荡器幅度稳定性比较差的问题,运用GL算法,通过电路参数的合理搭配,减小了振荡管基极工作点的漂移,得出了比以往更好的稳定中心.     

基于最小二乘支持向量机的电力电子电路故障诊断应用研究

采用最小二乘支持向量机预测算法对电力电子电路进行故障预测.以基本降压斩波电路为例,选择电路输出电压作为监测信号,提取输出电压平均值及纹波值作为电路特征性能参数,并利用LS-SVM回归预测算法实现故障预测.仿真结果表明,利用LS-SVM对基本降压斩波电路输出平均电压与输出纹波电压的预测相对误差均低于2%,能够跟踪故障特征性能参数的变化趋势,有效实现电力电子电路故障预测.     

压电超材料梁中弹性波带隙特性与界面传输的主动控制

该文采用周期压电负电容电路,研究了弹性波超材料梁中带隙特性的主动控制问题.该系统利用外部电路改变所连接压电材料的材料参数,从而改变结构的等效参数,实现对带隙特性的调控.通过对单胞进行控制,可观察到主动控制系统作用时带隙的产生与消失.构造了含有交界面的弹性波超材料梁结构,分析了主动控制系统对波动界面传输特性的影响.     

Variable neighbourhood structures for cycle location problems

Variable neighbourhood search is a metaheuristic used mainly to tackle combinatorial optimization problems. Its performance depends on having a good variable neighbourhood structure: that is, a sequence of neighbourhoods that are ideally pairwise disjoint and contain feasible solutions further and further from a given feasible solution. This article defines a variable neighbourhood structure with these properties that is new for cycle location problems. It find bounds for the neighbourhood sizes and shows how to iterate over then when the cycle is a circuit. It tests the structure and iteration method using variable neighbourhood search on a range of median cycle problems and finds a neighbourhood size beyond which there is, on average, no benefit in applying local search. This neighbourhood size is found not to depend on problem size or bound on circuit length.     

Some Applications of the Generalized Travelling Salesman Problem

In the Generalized Travelling Salesman Problem (GTSP), the aim is to determine a least cost Hamiltonian circuit or cycle through several clusters of vertices. It is shown that a wide variety of combinatorial optimization problems can be modelled as GTSPs. These problems include location-routeing problems, material flow system design, post-box collection, stochastic vehicle routeing and arc routeing.     

关于n中取连续k系统

n中取连续k系统是以电信、石油输送管道系统为背景于1980年提出的问题,之后很快发现这种系统在集成电路设计、卫星接力通讯系统。电话线路设计等实际问题中也有用,因此吸引了许多人的注意,成为可靠性中的一个活跃的研究课题。本文较详细地介绍了十年来在这个研究领域所取得的进展、尚未解决的问题和最新提出的一些课题,以便帮助有兴趣从事这方面研究的同志,很快进入研究的前沿。     

A note on weighted minimal cost flows

The minimal ratio problem which is treated in the literature for shortest paths [Dantzig/Blattner/Rao;Karp;Lawler, 1966, 1972] and for spanning trees [Chandrasekaran] is considered in a generalized form for network flow problems. The resulting problem of finding a so-calledweighted minimal cost flow can be solved by a negative circuit algorithm or by a shortest augmenting circuit algorithm. The validity of both algorithms follows from a negative circuit theorem which can be proved for weighted minimal cost flows.     

基于Web的数字集成电路仿真

针对高校实验教学所面临的问题,提出并实现了一个基于W eb的数字集成电路仿真实验平台.平台采用模型/视图/控制器M VC架构设计,基于J2EE开发平台实现,可以进行数字集成电路芯片的可视化表示、功能描述、电路搭建等仿真功能.仿真实验与综合性实验相结合,为高校实验教学改革探索出一条成功的新思路.     

Software Engineering and complexity in effective Algebraic Geometry

One may represent polynomials not only by their coefficients but also by arithmetic circuits which evaluate them. This idea allowed in the past fifteen years considerable complexity progress in effective polynomial equation solving. We present a circuit based computation model which captures all known symbolic elimination algorithms in effective Algebraic Geometry and exhibit a class of simple elimination problems which require exponential size circuits to be solved in this model. This implies that the known, circuit based elimination algorithms are already optimal.     

Thevenin decomposition and large-scale optimization

The Thevenin theorem, one of the most celebrated results of electric circuit theory, provides a two-parameter characterization of the behavior of an arbitrarily large circuit, as seen from two of its terminals. We interpret the theorem as a sensitivity result in an associated minimum energy/network flow problem, and we abstract its main idea to develop a decomposition method for convex quadratic programming problems with linear equality constraints, of the type arising in a variety of contexts such as the Newton method, interior point methods, and least squares estimation. Like the Thevenin theorem, our method is particularly useful in problems involving a system consisting of several subssystems, connected to each other with a small number of coupling variables.This research was supported by NSF under Grant CCR-91-03804.     

SOME COMBINATORIAL OPTIMIZATION PROBLEMS ARISING FROM VLSI CIRCUIT DESIGN

This paper is basically a survey to show a number of combinatorlal optimization problems arising from VLSI clrcult design.Some of them including the existence problem,minimax problem,net representation,bend minimization,area minimization,placement problem,routing problem,etc,are especially discussed with new results and theoretical ideas for treating them.Finally,a number of problems for further research are mentioned.     

平衡和不平衡运输问题与分配问题的通用迭代算法

将不平衡运输问题转化成网络最短路问题,利用Floyd算法规则,给出了一种既可以解平衡和不平衡运输问题,又可以解平衡和不平衡分配问题的通用迭代算法。与专门用于解运输问题的闭合回路法和专门用于解分配问题的匈牙利法相比,这种算法不但具有通用的优点,而且更便于在计算机上运行。     

An outer approximations algorithm for computer-aided design problems

This paper presents an implementable algorithm of the outer approximations type for solving nonlinear programming problems with functional inequality constraints. The algorithm was motivated by engineering design problems in circuit tolerancing, multivariable control, and shock-resistant structures.This research was sponsored by the National Science Foundation, Grant No. ENG73-08214A01, and the National Science Foundation (RANN), Grant No. ENV76-04264.