上海市计算机应用能力考核(初级)常见错误分析

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上海市计算机辅助绘图(初级)考核大纲

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关于L组合序列的结构

51．引言自Lehmer于1951年提出以来，乘同余发生器（MCG）x。二A。。1（。dM），tL。＝。。／M，。。为初值及线性同余发生器（LCG）x。2＊。。－1＋qmo6州，。n2x＊M，10为初值山已成为使用广泛的一类生成伪随机数（PRN）序列的手段．不过自六十年代以来，人们陆续发现MCG，LCG生成的PRN序列总存在一些结构上固有的缺陷＊．例如，点集｛儿计）＝《＊；＋l，…，tL；＋。），LE刚总位于R‘的单位立方体风中的有限块平行平面上，其中N表自然数集．Fishlnan与Moors曾对由MCG生成的PRN序列的结构作过深入研究问．大约自70年代中…     

用FOXPRO实现修改日期和时间的实用程序

借助命令RUN或！运行外部命令，往往使原来的屏幕被破坏，本文两个程序能实现不破坏屏幕的情况下修改日期和修改时间的功能。源程序如下：PROCEDUREMODIDATE＆＆修改日期SETDATETOAMERICANDEFINEWINDOWDATEWLNFROM20，15TO22，652；DOUBLESHADOWACTIVATEWINDOWDATEWINY＝”Y’NEWDATE＝DATE（）远对，OSAY’现在日期’＋I）T（）（”（＼EWDATE）＋’修改（Y／N）？’；GETI’l’ILT［TI＜E”1”’READIFY＝”Y”0”＠0，0SAY’请输入新日期：’（，1：lNI｛WDAAEREADSETC…     

2008年安防精品—腾龙光学（上海）有限公司

M13VG308／M13VM308（F=3．0-8mmF／1．0）对应百万像素摄像机的全新手动变焦镜头;13VG308ASIR／13VM308ASIR（F=3．0-8mmF／1．0）最畅销的标准手动变焦镜头;13FG221R／13FM221R（F=2．2mmF／1．2）超广角红外对应定焦镜头;12VG1040ASIR／12VM1040ASiR（F=10-40mmF／1．4）交通监控专用镜头;[第一段]     

访“情侣数”与“绝妙数”

毕达哥拉斯派将220和284称为一对“情侣数”，将6称为“绝妙数”。原因之一是220除本身以外的所有约数之和（1＋2＋4＋5＋10＋11＋20＋22＋44＋55＋110）为284，而284除本身以外的所有约数之和（1＋2＋4＋71＋142）又恰为220，这可以说是一对你中有我，我中有你的“情侣数”了。而6的除本身以外的所有约数之和（1＋2＋3）正好等于自身，可谓“绝妙数”。假如我们作如下的定义：设：任一自然数X除本身以外的所有约数之和为F（X）。定义①：若存在两个自然数A与B，满足F（A）＝B且F（B）＝A。则称A，B为一对“情侣数”。定义②：若存在…     

对称位相型滤波器及其在边缘检测中的应用

该文从概率的角度提出了两类新的滤波器：对称位相型滤波器和对称梯阶滤波器;证明了对任意给定的非负对称滤波器可用这两类滤波器的序列在（－∞,＋∞）内一致逼近;这种序列有着统一的结构形式：L（x）＝^s∑i＝1e^λi│x－μ│^Ni∑k＝0ak^（i）│x－μ│^ k。对于L（x）,文中给出了选择L（x）一些最优准则的解析表达。从而表明L（x）既具有一般性,又易进行解析处理和数值计算。对于已有文献中相关于对称指数滤波器的两类不同形式,例如Li等和Ma等,该文从理论上进一步刻画了它们的内在一致性。     

对WINDOWS3.1几个问题的处理

1．WIN］yJWS．1使用激光打印机打不出汉字主要原因是未设置“：llllerlarx－u”段或设置不当而引起，具体解决方法如下：（）检查“WIN．im”文件的“Tr－ueTgu”段中OUTine＝xx行，一代表一数字，缺省值为256，此值不能大于300，如无该行或该段，请加入。（2）检查“Tru6I？vr）e”段中7q：15nable＝X（X为0或1）0为不使用TruerW字段，1为使用，如为0应改为1，具体做法可用如下任意一种：①在WINIX）WS内，选程序管理器～主群组一控制面板～打印机，选好所配打印机，在该对话框内选“设置”，在“设置”对话框内选“选项”，在…     

互不同随机整数序列的快速选取算法（FSR）研究

研究互不同相的随机整数序列的选取算法是一个非常重要的课题，这里我们给出了一种采用二分技术的互不相同的随机整数快速选取策略（FSR），并证明了采用该算法在某一区间（M，N）内选取R个互不相同的随机整数所需的步长仅O[log2R]，其随机周期达到（N－M－1）！／（N-M-1-R)!，而经典算法所需的步长的R，其随机周期仅为（N－M－1）。     

N，N-二甲基二2-溴苯乙胺类衍生物活性与CoMFA、CoMSIA的研究

用比较分子力场分析（CoMFA）法和比较分子相似性指数分析（CoMSIA）法，建立N，N-二甲基-2-溴苯乙胺类化合物的3D—QSAR模型。CoMFA模型中，其交叉验证系数q^2=0．792，传统的相关系数R^2=0．955（R=0．978），相应立体场贡献为77．4％、静电场贡献为22．6％，优于文献的报导。CoMSIA研究中，其交叉验证系数q^2=0．757，传统的相关系数R^2=0．917（R=0．958），其疏水场、立体场、静电场贡献依次为：42．9％、39．5％、17．6％。用两种模型分别预测检测集分子的活性，结果与实验值较吻合。说明所建的模型具有较好的预测能力。通过分析CoMFA分子场等值线图，可为优化N，N-二甲基-2-溴苯乙胺类衍生物的结构提供理论指导。     

On the inequality of cover and hart in nearest neighbor discrimination

When (X1, ?1),..., (Xn, ?n) are independent identically distributed random vectors from IRd X {0, 1} distributed as (X, ?), and when ? is estimated by its nearest neighbor estimate ?(1), then Cover and Hart have shown that P{?(1) ? ?}n ? ? ? 2E {? (X) (1 - ?(X))} ? 2R*(1 - R*) where R* is the Bayes probability of error and ?(x) = P{? = 1 | X = x}. They have conditions on the distribution of (X, ?). We give two proofs, one due to Stone and a short original one, of the same result for all distributions of (X, ?). If ties are carefully taken care of, we also show that P{?(1) ? ?|X1, ?1, ..., Xn, ?n} converges in probability to a constant for all distributions of (X, ?), thereby strengthening results of Wagner and Fritz.     

模糊集间的R_0-相似关系及其性质

将王国俊教授在R0-型逻辑系统中建立的R0-蕴涵算子应用于模糊数学理论之中,在非空集合X为论域的模糊集族F(X)上定义了一种新型运算-R0蕴含运算,并讨论了F(X)上R0-蕴含运算的一些基本性质。通过R0-蕴含运算在F(X)上定义了一个二元模糊相似关系-R0-相似关系,并对其性质进行了较为详细的讨论。在有限论域X确定的模糊集族F(X)上给出了几个R0-相似关系的具体实例。     

Solving Underdetermined Systems with Interval Methods

In this paper, we use the concepts of {1} - and {2} -inverse of a matrix to construct such a Krawczyk-like operator as

环[F2+uF2+vF2]上的[(1+v)-]常循环码

研究了环[R=F2+uF2+vF2] 上的[(1+v)-]常循环码。利用环[R]上奇长循环码的生成元来刻画环[R]上奇长的[(1+v)-]常循环码,进而给出了[Rn]到[(F2+uF2)2n]的一个广义Gray映射[φ],证明了环[R]上的[(1+v)-]常循环码[C]在[φ]下的广义Gray像[φ(C)]是环[F2+uF2]上的循环码。     

Alcune considerazioni numeriche relative alla soluzione di un noto problema ai limiti per l'equazionex=f(t,x,λ)

An iterative method for the computation of the solution of a boundary value problem for the equation is discussed from a numerical point of view. A practical exemple is also given.

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Lavoro eseguito nell'ambito del Gruppo n^o 11 del Comitato per la Matematica del C.N.R. nel corso dell'anno accademico 1967–68.     

A multi-model reference control approach for bandwidth-on-demand protocols in satellite networks

This paper presents a multi-model reference control (MMRC) approach for queue-based bandwidth-on-demand (BoD) procedures in geostationary satellite networks. BoD access protocols address the problem of guaranteeing a high exploitation of the valuable satellite bandwidth while offering acceptable end-to-end delays to the traffic accessing the network. In queue-based protocols, the controller objective is to drive the buffer queue length to a certain target queue length; in the proposed scheme, model references (MRs) are used to address the problem of adapting the target queue length to the statistical characteristics of the traffic. The reference queue length is computed as a weighted sum of the outputs of the different MRs; the weights are computed on-line by evaluating the network utilization achieved by each MR, in response to the actual traffic feeding the system. Moreover, the target network utilization is dynamically varied based on the estimated network load. The BoD performances are evaluated via simulations. The work underlying this paper is based on the results of the GEOCAST,¹ SATIP6² and SATSIX³ projects, financed by European Union.     

Numerical Experiences with a New Generalized Subinterval Selection Criterion for Interval Global Optimization

The convergence properties are studied for interval global optimization algorithms that select the next subinterval to be subdivided with the largest value of the indicator pf(f _k, X) = . In contrast to previous work, here the more general case is investigated, when the global minimum value is unknown, and thus its estimation f _k in the iteration k has an important role.Extensive numerical tests on 40 problems confirm that substantial improvements can be achieved both on simple and sophisticated algorithms by the new method (not utilizing the minimum value).     

Any discrimination rule can have an arbitrarily bad probability of error for finite sample size

Consider the basic discrimination problem based on a sample of size n drawn from the distribution of (X, Y) on the Borel sets of Rdx {0, 1}. If 0 < R*. < ? is a given number, and ?n ? 0 is an arbitrary positive sequence, then for any discrimination rule one can find a distribution for (X, Y), not depending upon n, with Bayes probability of error R* such that the probability of error (Rn) of the discrimination rule is larger than R* + ?n for infinitely many n. We give a formal proof of this result, which is a generalization of a result by Cover [1]. Furthermore, sup all distributions of (X, Y) with R* = 0 Rn > ?. Thus, any attempt to find a nontrivial distribution-free upper bound for Rn will fail, and any results on the rate of convergence of Rn to R* must use assumptions about the distribution of (X, Y).     

The average number of registers needed to evaluate a binary tree optimally

Summary In this paper we determine the number of binary trees with n leaves which can be evaluated optimally with less than or equal to k registers. Furthermore we obtain the result that this number is equal to the number of the binary trees with n leaves, using for traversal a maximum size of stack less than or equal to 2^k+1–1. This fact is only a connection between the numbers of the trees and not between the sets of the trees. We compute also the average number ¯R(n) of registers needed to evaluate a binary tree optimally. We get for all >0: where C = 0.82574... is a constant and F(n) is a function with F(n) = F(4n) for all n>0 and –0.574相似文献   

A family of maximal noncontrollable Lie wedges with empty interior

Let S_k be the semigroup of matrices in having nonnegative k-minors. Its Lie wedge generates and is noncontrollable. It is proved here that is a maximal noncontrollable Lie wedge if k=1, n−1 or when k and n are even. The latter is the family of Lie wedges mentioned in the title.