度量空间中的Lipschitz道路及其*积运算

通过距离空间(X,d)上Lipschitz映射,引入了X中的Lipschitz道路的概念,研究了它的一些性质,证明了同一度量空间中两个相交的Lipschitz道路的并也是Lipschitz道路。引入了度量空间X,Y中的Lipschitz道路E,F关于h:[0,1]→E与g:[0,1]→F的*-积E*F│(h,g),证明了当h,g都是Lipschitz满射时E*F│(h,g)为乘积空间X×Y中的Lipschitz道路。     

随机自相似测度的量子化维数和它的分布之间的关系

文章主要讨论了随机自相似集K(ω)上的随机自相似测度μ的量子维数,建立了μ的量子维数和它的分布之间的关系,并且给出了这个公式的一个简单应用。     

固定——夹紧一体化即时逃生装置

<正>一、设计方案本产品由两部分组成。(1)固定--夹紧装置:丝杠(自锁螺纹);左右两侧支架;半球自锁螺母;摩擦盘等。(2)缓降逃生装置:摩擦滑块(8个);外壳;齿轮-1;齿轮-2;绳索;(钢丝绳);安全     

社区自组织能力建设的体制、政策法律路径

社区建设启动以来,社区的自组织机制得以恢复并逐步发育,但政府与社区的关系尚未有根本性的改变,居民及其自治组织更多地是在扮演"被组织"者的角色.这已成为制约社区建设和社区自组织能力进一步发展的瓶颈.因此,提升社区自组织能力不能局限于社区共同体本身,还需着眼于体制、政策、法律这些外部社会环境.文章就此作了两个方面的重点对策分析:(1)以理顺政府与社区的关系为关键,拓展社区自组织能力的体制空间;(2)以居民自治为着力点,拓展社区自组织能力的政策法律空间.     

结合GMDH算法与AC算法建模的汇率预测

汇率波动预测是金融市场的一个重要课题,本文结合GMDH算法(分组数据处理算法)和AC算法(相似体合成算法)建立模型用于预测汇率市场的波动。首先用相似体合成算法选择与当前时期有相同特征的相似体,再用分组数据处理算法将相似体进行加权组合,选择最优模式,用于预测当前时期的发展趋势。实证结果表明,此组合模型的预测效果较好。     

水平仪检定器测量不确定度的评定

1 概述依据JJG191-1979《水平仪检定器》检定规程，根据规程的要求，使用立式光学计配上不同尺寸的量块对水平仪检定器的分值进行检定。2 建立数学模型，列出不确定度传播率2.1 数学模型水平仪检定器的示值计算公式为 N= (1)式中：N——检定时水平仪检定器实测值，格； L——光学计测量轴线至检定器工作台回转轴线间 的距离，L＝(0.2±0.0005)m; x——光学计的读数，mm; d——检定器的标称分度值，d=0.005mm/m。则水平仪检定器的分度值误差e（即每格的误差）为：△ε＝ ×…     

自相似流量模拟的Hurst参数实时计算

Hurst参数是自相似流量模拟重要参数。本文采用R/S法对Hurst系数进行实时计算,在此基础上提出通过实际的Hurst系数与理论Hurst系数的比较来衡量模拟流量与理论模型的差别。     

基于不同空间权重矩阵的我国省域经济空间效应研究

运用Geoda空间分析软件,针对我国31个省市(港澳台除外)的2001-2020年GDP,运用不同权重矩阵进行空间相关分析和动态变化分析.基于"后"型、K-最近邻和欧式距离空间权重矩阵进行全局和局部空间自相关分析.结果表明不同权重矩阵的全局Moran'sI指数检验都有显著的空间相关性,其中K最近邻矩阵时达到最大.我国省域经济呈现局部聚集性分布,不同空间权重矩阵在检测省域经济中,"高-高""低-低""高-低""低-高"空间聚集性方面存在一定差异.结论我国省域经济存在显著全局及局部自相关性.结合不同的空间权重矩阵进行综合分析,有助于深入掌握我国省域经济分布特征,为合理配置资源提供依据.     

产品质检测量中不确定度评估分析

产品质量检验测量中不确定度的来源一般有:测量方法、抽取样本代表性、测量环境、测量仪器、测量用标准样品等等。对于那些尚未认识到的系统效应,可能未在不确定度评定=0.0003μX天:分析天平证书给出变动性≤0.1%,方法称量0.1000g。X=0.051%,则:μX天(%)= =0.0002μX容(%):估计给出0.0002μX标(%):共选用4个国家球墨铸铁标准样品,样品证书分别给出不确定度。μX标(%)= μ标12+μ标22+μ标33+μ标42 =0.00062+0.0012+0.00082+0.0012 =0.0017μX原(%):估计给出0.0003则:μB(%)= μX天2+μX容2+μX标2+μX原2 =0.00022+0.0002…     

20g二等砝码测量不确定度分析

1 概述1.1 测量依据:JJG 99-1990《砝码(试行)检定规程》1.2 测量标准:一等标准砝码,标称值:20g由JJG 99-1990《砝码(试行)检定规程》给出其扩展不确定度U=0.04mg,k=3。1.3 环境条件:温度(18～23)℃,温度波动≤1℃/4h,相对温度≤70%。1.4 被测对象:二等砝码,标称值:20g。1.5 测量方法:采用单次替代法,在最大称量为20g,实际分度值d=0.01mg的3级标准天平上进行检定,然后根据规程提供的公式进行计算,算出被测砝码的折算质量。2 数学模型mA=mB+Δm式中:mA:二等被测砝码折算质量值 mB:一等标准砝码折算质量值 Δm:被测与标准砝码的…     

移动自组网流量仿真及特征分析

本文对基于用户行为的计算机网络流量模型进行了改进,并将其应用于移动自组网流量仿真中,同时对仿真流量进行了特征分析,得出移动自组网网关流量具有自相似性特征的结论。     

A strategic analysis of network reliability

Abstract. We consider a non-cooperative model of information networks where communication is costly and not fully reliable. We examine the nature of Nash networks and efficient networks. We find that if the society is large, and link formation costs are moderate, Nash networks as well as efficient networks will be ‘super-connected’ i.e. every link is redundant in the sense that the network remains connected even after the link is deleted. This contrasts with the properties of a deterministic model of information decay, where Nash networks typically involve unique paths between agents. We also find that if costs are very low or very high, or if links are highly reliable then there is virtually no conflict between efficiency and stability. However, for intermediate values of costs and link reliability, Nash networks may be underconnected relative to the social optimum.     

Stochastic labelling of biological images

Many hypotheses made by experimental researchers can be formulated as a stochastic labelling of a given image. Some stochastic labelling methods for random closed sets are proposed in this paper. Molchanov (I. Molchanov, 1984, Theor. Probability and Math. Statist. 29 , 113–119) provided the probabilistic background for this problem. However, there is a lack of specific labelling models. Ayala and Simó (G. Ayala and A. Simó, 1995, Advances in Applied Probability 27 , 293–305) proposed a method in which, given the whole set of connected components, every component is classified in a certain phase or category in a completely random way. Alternative methods are necessary in case the random labelling hypothesis is not reliable. A different kind of labelling method is proposed that considers the environment: the type of every connected component is a function of its location.
Two different biphase images are studied: a cross section of a nerve from a rat, and a cross section of an optic nerve from a lizard.     

Bifurcations in regional migration dynamics

The tomahawk bifurcation is used by Fujita et al. [Fujita, M., Krugman P., Venables A.J., 1999, The Spatial Economy: Cities, Regions, and International Trade, MIT Press: Cambridge, MA.] in a model with two regions to explain the formation of a core–periphery urban pattern from an initial uniform distribution. Baldwin et al. [Baldwin, R., Forslid, R., Martin, P., Ottaviano, G.I.P., Robert-Nicoud, F., 2003, Economic Geography and Public Policy, Princeton University Press: Princeton, NJ.] show that the tomahawk bifurcation disappears when the two regions have an uneven population of immobile agricultural workers. Thus, the appearance of this type of bifurcation is the result of assumed exogenous model symmetry. We provide a general analysis in a regional model of the class of bifurcations that have crossing equilibrium loci, including the tomahawk bifurcation, by examining arbitrary smooth parameter paths in a higher dimensional parameter space. We find that, in a parameter space satisfying a mild rank condition, generically in all parameter paths this class of bifurcations does not appear. In other words, conclusions drawn from the use of this bifurcation to generate a core–periphery pattern are not robust.     

Towards a theory of optimal roads

The purpose is to find an allocation of a given total amount of road capital in two-dimensional space such that total transportation costs for a region are minimized. A continuous model in analogy to hydrodynamics is used. Transports are supposed to be generated by the gravity hypothesis. It is discussed how transportation paths are optimally adjusted to a given distribution of road capital, and how road capital should be distributed at a given traffic distribution. It is also discussed how the latter problem should be solved when it is taken into account that the distribution of roads affects the choice of paths.     

Een Monte-Carlo-bepaling van overschrijdingskansen, in verband met een keuzetest

A Monte-Carlo method for a test of significance, applied to points on a lattice, in connection with a vocational preference test, by C. A. G, Nass.
Appendix by Constance van Eeden.
A periodical rectangular lattice, with a period of k.m, is considered. Thus there are N = k.m points on the lattice, repeated in the two perpendicular directions. Two points are said to be "connected" if they are adjacent in a straight or diagonal way. Thus, if k and m 3, every point is connected with 8 other pooints. Out of the N points of the lattice, n points are selected and the total number of connections x, of all possible pairs of those n points is considered for a vocational preference test with k = m = 9, N = 81, n = 10. The problem is to test whether the sum y = x₁+…+ x*** from a sample of h values of x, is significantly small, under the hypothesis that in the h cases the n points are selected at random with equal chance. A Monte-Carlo sample of 100 values of x was taken, using random numbers. For h = 1, the problem was solved by the determination of P( y x₁), assuming that y is taken at random from the 101 values of x, supplied by the Monte-Carlo sample and x₁ for fixed values of x₁. For h - 2, a similar solution is given. For greater values of h, Student's two-sample test, with correction for continuity is suggested. For h = 2 the results of Student's test are compared with those of the solution mentioned above.
In the appendix a summary is given of results found by P.A.P Moran and P. V. Krishna Iyer for some closely related problems. Further some results concerning exact distributions, moments and asymptotic distributions for C. A. G. Nass' problem are given. The proofs of these results may be found in a paper by C. van Eeden and A. R. Bloemena (1959).     

知识管理及其实施

在简评了目前对知识管理的两种主要研究角度的基础上 ,总结了在这些思路下实施知识管理的主要途径 :进一步对知识管理的对象进行了深入的讨论 ;并结合实际状况 ,提出在现阶段全面实施知识管理对大多数企业并不现实。最后 ,结合团队这一组织形式 ,提出在小范围内特别是工作团队内开展知识管理是知识管理实施突破口之一的观点。     

Inequalities relating maximal moments to other measures of dispersion

Let X , X ₁, ..., X_k be i.i.d. random variables, and for k ∈ N let D_k ( X ) = E ( X ₁ V ... V X _{k +1}) − EX be the k th centralized maximal moment. A sharp lower bound is given for D ₁( X ) in terms of the Lévy concentration Q_l ( X ) = sup _{x ∈ R} P ( X ∈[ x , x + l ]). This inequality, which is analogous to P. Levy's concentration-variance inequality, illustrates the fact that maximal moments are a gauge of how much spread out the underlying distribution is. It is also shown that the centralized maximal moments are increased under convolution.