擂台赛

问题:对于键盘输入的自然数K(K>1),若存在自然数M和N(M>N),使得K~M和K~N均大于等于1000,且它们的末尾三位数字相等,则称M,N为一对“K尾相等数”。 请编一程序,输出所有K尾相等数中,M+N的最小值。 分析:本期擂台赛是一道数字题,解决这道题的方法有很多,但是关键是如何控制问题的规模,提高程序的效率,因为K~N是按指数增长的,如果采用枚举的方法,数字将很快超过计算机所能处理的范围。由此要想以较高的效率解决这道题,必须明确以下几     

基于组合学的大规模磁盘队列轮换休息机制的编码设计

在大规模存储的系统中,运用组合学方法实现了磁盘队列轮换休息机制的编码算法,该机制能极大的提高磁盘的平均无故障时间和延长使用寿命.具体通过圆排列映射的数学建模方法,连续两次应用抽屉(鸽巢)原理,设计了从N个磁盘中随机取出M个磁盘(M＜N),让其中一个或数个磁盘断电休眠,用剩余磁盘还原休眠磁盘的组合学编码算法.     

云存储系统中文件分界点确定方法——Cut-GAR

针对Hadoop分布式文件系统(HDFS)中小文件定义模糊导致HDFS处理小文件性能不佳的问题,提出了一种云存储系统中文件分界点的确定方法——Cut-GAR。该方法分析消耗NameNode内存(M)、文件上传速度(MUFS)、文件读取速度(MAFS)与文件大小之间的关系,得出文件大小三个近似最优值,FM、FMUFS、FMAFS;然后利用灰度关联分析,将M、MUFS、MAFS作为评价指标,文件大小作为评价对象,得到评价指标-评价对象灰色关联度以及评价指标所占权重,将FM、FMUFS、FMAFS与对应权重相乘,得出文件分界点。实验结果表明,Cut-GAR在M、MUFS 和MAFS三者之间取得平衡,可以有效确定文件分界点,提升小文件处理性能。     

无线认知网络中一种团划分的频谱感知算法

提出了一种基于节点之间竞争关系以及感知代价的分布式频谱感知算法.该算法基于分布式最小团划分理论,将节点划分至不同的团中,然后再根据团的结构来计算最优频谱感知分配.该算法的时间复杂度仅为O(N2+M×N),其中,N为网络中节点数,M为信道数目.大量的仿真实验结果表明,该算法能够有效地提高网络性能.     

擂台赛

1996年第3期擂台赛讲评 所谓素数,指的是除1之外只能被1和它本身整除的正整数。 由此,我们不难得出解决此问题的方法: (1)对任何一个正整数N,首先判断它是否是素数,判断的方法是:用N依次与2到M间的每整个数相除,若都除不尽,则N为素数,否则N不是素数. 那么,M的值又如何确定呢?最简单、最容易想到的就是取M=N-1.但是,请大家注意,我们在评     

跟我学作DP—801单片机系统（六）

用DP801奏乐 DP801不仅能控制发光二极管点亮和熄灭,而且还可以奏乐,下面先介绍三条指令,然后举一个应用实例。一、介绍三条指令 1.奏乐指令指令助记符指令机器码书写方式:ZY N,M 03 N,M 说明:“ZY”为“奏乐”二字的拼音缩写。这是一个三个字节的指令,03是操作码,N和M为操作数。指令的功能:从喇叭插座上输出音频信号,能演奏音乐。该指令的两个操作数N为音高,M为音长。DP801提供三组音程,从低音C到高音B,按等阶音程排列共21个乐音,再加上一个休止符,有效操作数为22个,     

一种区块链数据的云存储与共享方法

为了在不信任的环境中达成共识,区块链节点需要冗余地存储完整的区块链数据,对节点的存储要求很高.提出一种区块链数据的存储方法,设置M个云存储共享模块用于存储完整的区块链以及节点数字签名,节点将区块及其数字签名存储到若干个云存储共享模块.当区块链节点数量N足够大时,能够选择合适的M(M<相似文献   

软计算求解并行多机成组工件提前/拖期惩罚调度问题

1　问题描述成组工件提前 /拖期惩罚调度在实际生产中普遍存在、急待解决又十分复杂 .目前在国内外相关杂志上 ,还未见报道能够有效解决实际规模问题的方法 ,本文提出了软计算方法( SC) ,实验结果证明了它可以有效地解决大规模实际问题 .N个工件 ( b组 ,每组 ni个工件 ) ,M台机     

1998年第6期擂台赛题目

对于键盘输入的自然数K(K>1),若存在自然数M和N(M>N),使得K~M和K~N均大于等于1000,且它们的末尾三位数字相等,则称M,N为一对“K尾相等数”。 请你编一程序,输出所有K尾相等数中,M+N     

非均匀内热源对多孔介质内复合对流传热传质的数值研究

采用数值方法分析了具有非均匀内热源的竖直套管中复合对流传热传质,考查内热源分布系数M和热质二浮力比N对速度、温度、浓度分布以及Nusselt数和Sherwood数的影响,讨论了Da数对复合对流传热传质的影响.结果表明:当N＞1时速度V为正,其值随N的增加而增大:当N＜-1.5时,V则先负后正.随着M增大,内外壁面处流线...     

Minimality, stabilizability, and strong stabilizability ofuncertain plants

This paper considers a set of uncertain transfer functions whose numerator and denominators belong to independent polytopes. It shows that i) the members of this set are free from pole-zero cancellations iff all the ratios of numerator edges and denominator edges are free from pole-zero cancellations and the numerator and denominator corners evaluated at a finite number of points satisfy certain phase conditions, ii) the members of this set are free from pole zero cancellations in the closed right half plane, iff all the ratios of numerator edges and denominator edges are free from pole-zero cancellations in the closed right half plane, and the numerator and denominator corners evaluated at a finite number of points satisfy certain phase conditions, and iii) in the strictly proper case, all plants in the set are strongly stabilizable iff all plants avoid pole-zero cancellations in the closed right half plane and all the corner ratios are strongly stabilizable. A counter-example is presented to show that this last result does not extend to biproper plants     

Robust positive realness of functions with dependent parameter uncertainty in numerator and denominator

This paper is concerned with the robust positive realness (PRness) and strict positive realness (SPRness) of a family of rational functions with the numerator and denominator simultaneously dependent on the same set of parameters. We show that under certain conditions only the extreme values and certain edges of the parameter bounding set are needed for testing the robust PRness and SPRness of the family

     

Extreme point results for robust stabilization of interval plantswith first-order compensators

It has been shown previously that a first-order compensator robustly stabilizes an internal plant family if and only if it stabilizes all of the extreme plants. These extreme plants are obtained by considering all possible combinations for the extreme values of the numerator and denominator coefficients. In this work, the authors prove a stronger result, namely, that it is necessary and sufficient to stabilize only sixteen of the extreme plants. These sixteen plants are generated using the Kharitonov polynomials associated with the numerator and denominator. Furthermore, when additional information about the compensator is specified (sign of the gain and signs and relative magnitudes of the pole and zero), then, in some cases, it is necessary and sufficient to stabilize eight critical plants, while, in other cases, it is necessary and sufficient to stabilize twelve critical plants     

菱形对象族的鲁棒镇定*

本文研究了菱形对象族的鲁棒镇定问题，证明了控制器鲁棒镇定菱形对象族的充分必要条件是它同同时镇定六十四条棱边对象，在此基础上，利用凸方向的概念讨论了控制器分子、分母的选择，并给出了菱形对象族的顶点镇空结果。     

On the thirty-two virtual polynomials to stabilize an intervalplant

This paper studies the conservatism of the 32 virtual polynomials to stabilize an interval plant. It is shown that working with the 32 virtual vertices is generally less conservative than with the Kharitonov polynomials of the smallest interval polynomial containing the characteristic polynomial polytope. By means of the former, it is possible to find all the controllers such that the value set of the polytope of characteristic polynomials is applied in two quadrants as a maximum for each ω; while using the latter, only some of them can be found. The cases in which both methods coincide are also analyzed, and the conditions on the numerator and denominator of the controller are developed. Thus, this coincidence can be known a priori from the characteristics of the coefficients of the numerator and denominator of the controller. It is shown that these conditions are satisfied by the first-order controllers     

基于近似最大公因多项式问题的公钥密码方案

研究了有限域F2上有随机噪声的一组多项式的近似最大公因式问题,提出了基于近似最大公因多项式问题的公钥密码方案。证明了方案的正确性并归约证明了方案的安全性等价于求解近似最大公因式问题,同时讨论了对于该方案可能的攻击方式。通过与现有公钥系统比较,该方案的安全性和可靠性较高,运算速度较快。     

Optimizing simultaneously over the numerator and denominator polynomials in the Youla-Kuc/spl caron/era parametrization

Traditionally, when approaching controller design with the Youla-Kuc/spl caron/era parametrization of all stabilizing controllers, the denominator of the rational parameter is fixed to a given stable polynomial, and optimization is carried out over the numerator polynomial. In this note, we revisit this design technique, allowing to optimize simultaneously over the numerator and denominator polynomials. Stability of the denominator polynomial, as well as fixed-order controller design with H/sub /spl infin// performance are ensured via the notion of a central polynomial and linear matrix inequality (LMI) conditions for polynomial positivity.     

二元向量有理插值的NEVILLE计算公式

１．引 言 在机械振动的数据分析等方面，向量值函数的有理插值与逼近有着广泛的应用．Ｇｒａｖｅｓ－Ｍｏｒｒｉｓ系统地研究了一元向量值函数的有理插值问题［１－３］．朱功勤等自 １９９０年开始将一元的结果成功地推广到了二元的情形［４－７］．设由平面上相异点组成的点集为其对应的有限向量集为［５］给出了其中满足向量值函数的有理插值问题与下述向量的逆密切相关，其中ｆ＝（ｆ１，ｆ１，…，ｆｄ）Ｒｄ并且对于（１．４）的特殊情况，约定称ｄ维向量值多项式的次数为ｎ且记为｛Ｎ（ｘ，ｙ）｝＝ｎ，如果对任意ｊ＝１，２，…，…     

Application of generalized block-pulse operational matrices for the approximation of continuous-time systems

The central theme of this paper is to apply generalized block-pulse operational matrices to approximate continuous-time systems. Generalized block-pulse operational matrices and the Routh approximation method are used together to find a low-order transfer function to approximate the original high-order transfer function. The Routh approximation method is used to preserve the stability of the original system by first determining the denominator coefficients of the reduced-order system. Generalized block-pulse operational matrices are then applied to determine numerator coefficients of the reduced-order system by optimally matching the unit step responses of the original and reduced-order systems. This new constrained time-domain matching approach not only yields more satisfactory results than previous methods, but also provides a more straightforward and efficient method for the approximation of continuous-time systems.     

To stabilize an interval plant family it suffices to simultaneouslystabilize sixty-four polynomials

It is shown that stability of three specific polynomial families can be deduced from the stability of a finite number of polynomials. These polynomial families are the characteristic polynomials of unity feedback loops with the controller in the forward path, and where the plant includes a specific form of parameter uncertainty. For the first polynomial family, the plant has parameter uncertainty in the even or odd terms of the numerator or denominator polynomial. For the second polynomial family the plant has a numerator or denominator which is an interval polynomial. For the third polynomial family, the plant is interval. Because of the structure of these results it is shown that they lead to robust stabilization results. Two examples are included. The approach employed here was developed for plants with affine uncertainty. It is demonstrated that considerable simplification results if the plants under investigation are interval