分布

We will see how data can be characterized as observed values of random variables and study three important probability distributions: the uniform distribution, the binomial distribution, and Normal distribution.

我们会看到资料如何表现随机变数观测值的特征，并且研读三种重要的概率分布：均匀概率分布，二项分布与正态分布。

It is obvious to see that bivariate copulas is a very useful tool for constructing bivariate distributions, especially when the marginal distributions are given of the same type of distribution such as bivariate exponential distribution and bivariate gamma distribution.

由回顾知道，经由二元机率合函数以建立二元分布是一项很有用的工具，尤其是边际分布为特定分布时，如边际分布为同类型时之二元指数、二元迦玛等等。

We take them as examples for listing the microcanonical distribution,the canonical distribution and the grand canonical distribution for illustrating the idea.

本文根据刘维方程讨论了经典系统和量子系统处于平衡态时分布函数和统计算符应当具有的普遍函数形式，并以常用的微正则分布、正则分布和巨正则分布予以印证。

We take them as examples for listing the micro canonical distribution ,the canonical distribution and thegrand canonical distribution for illustrating the idea.

本文根据刘维方程讨论了经典系统和量子系统处于平衡态时分布函数和统计算符应当具有的普遍函数形式，并以常用的微正则分布、正则分布和巨正则分布予以印证。

According to model, lead zinc ore bodies of mineral deposit, celestite ore bodies and gypsum ore bodies are distributed by the incomplete dome shape. The sandstone type ore bodies like a curved surface shape, is on the top, wide distribution, which like the top cover of a mushroom. The limestone breccia type ore bodies, under the sandstone type ore bodies, with mostly irregular vein shape, lens body shape, locate at the root of the mushroom. Gypsum and celestite ore bodies, accompanying with limestone breccia type ore bodies with the shape of vein, lens body, distribute under the sandstone type ore bodies.

根据模型显示，金顶矿床铅锌矿体、天青石矿体和石膏矿体呈不完整的穹隆状分布，砂岩型矿体在上，为曲面状，分布广，似一蘑菇的顶盖，而灰岩角砾岩型矿体分布局限，部分产于砂岩型矿体之下，多为不规则的脉状、透镜体状，构成蘑菇的根部；石膏和天青石矿体主要与灰岩角砾型矿体相伴产出，呈脉状、透镜体状，多分布于砂岩型矿体下部。

1Niche construction can lead to stable coexistence of diverse genotypes in spatially structured population, which supports a stable polymorphism even without heterozygote superiority.(2)With habitat deterioration, niche construction accelerates the formation of steady polymorphism and hence impedes the harmful influences of environment on the population, which might embody a life-history strategy of organism under the unfavorable environment.(3)Niche construction results in the coexistence with alternative polymorphism through genotype-environment feedback and limited gene flow.(4)The niche-constructing organism is an active force to alter its environment and hence the direction of natural selection in order to better survival.(5)Spatial dynamics and distribution pattern of metapopulation are profoundly influenced by time-lagged niche construction.(6)Metapopulation size can reach a fixed level in the recency effect and equal weighting of time lag but is statistical stability in primacy effect, which implies the primacy effect is most remarkable.(7)The increment in the relative weightingof each generation\' niche construction and the length of time lag are significant factors for system destabilization.(8)Moderate capacity of positive niche construction benefits the metapopulation persistence.(9)The narrowing of niche breadth can decrease the metapopulation size and thereby increase the extinction risk.(10)The coupled function of time lag and niche construction make the system oscillation and generate the spiral wave, spiral-broken and circular wave in heterogeneous habitat.The spatial distributions of metapopulation and resource content are complementary due to a phase lag of their both frequencies.(12)Metapopulation persistence with niche construction depends not only on the balance between colonization and extinction, but also on the balance between the ability of niche construction and natural dissipation of habitat.(13)Metapopula-tion can survive under certain condition when the percent of suitable patches in habitat is lower than the ration of extinction to colonization.(14)Two thresholds exist in the process of transition of habitat quality dynamics from unsuitable to suitable, which include the intensity of niche construction and the initial condition of system.(15)Metapopulation size is positive correlated with the ability of positive niche construction, which means that organism or population who has strongly positive influences on their environment plays an important role to maintain the available habitat.

通过上述几个方面的研究，主要得出以下15条结论：(1)生态位构建可使空间结构种群，甚至是在没有杂合子优势的条件下，形成多种可能的稳定基因型分布模式；(2)随着环境的破坏与恶化，种群的生态位构建作用加速其较早形成稳定多态以阻碍环境对种群的不利影响，解释了有机体在不利环境下的一种生活史对策；(3)生态位构建作用通过基因型—环境反馈机制及有限的基因交流导致基因型多态的稳定共存；(4)有机体的生态位构建作用是一种积极的动力改变环境进而改变其自然选择的方向；(5)生态位构建的时滞作用对集合种群动态和空间分布产生深刻影响；(6)集合种群大小在时滞的崭新效应和等权重效应下达到一固定值，而在首位效应下达到统计稳定，表明首位效应的影响最显著；(7)首位效应下生态位构建相对权重的增量和时滞的长度是影响系统不稳定性动态的关键因素；(8)适中的生态位构建强度有利于集合种群的续存；(9)生态位宽度变窄会减少集合种群的数量从而增加其灭绝风险；(10)时滞和生态位构建的双重作用使系统产生周期振荡，并在异质性环境中产生稳定的螺旋波，破碎的螺旋波和环形波三种分布模式；(11)集合种群与资源含量的空间分布因为相滞而互补；(12)具有生态位构建的集合种群续存不仅取决于侵占率与灭绝率之间的平衡，而且依赖于生态位构建能力同其生境的自然消耗速率之间的妥协；(13)当生境中适合侵占的斑块比例小于其侵占率与灭绝率之比时，生态位构建作用促使集合种群在一定条件下续存：(14)生境斑块的状态从不适合到适合转变过程中存在生态位构建强度和系统初始条件这两个阈值；(15)集合种群的大小同正生态位构建能力正相关，意味着对环境具有较强正作用的有机体对维持有效生境起积极作用。

The main topics include probability space, discrete distribution, continuous distribution, multivariable distribution conditional distribution and the sampling distribution theory.

课程方要课题含机率空间、离散分布、连续分布、多变量分布及抽样分布等的简介。

For the aforesaid reasons, in the second chapter ,this article estimates some parameters in the two-parameters Weibull distribution by the hybrid ALT method,and gives the inverse moment estimator for the shape parameter,at the same time the confidence interval of the accelerated coefficient is given .

基本研究问题：设应力水平V下产品的寿命服从两参数威布尔分布，则在混合应力加速寿命试验下产品寿命T的分布函数为：记T/t_0=X则X的分布函数为其中令λ=θ~m由上式得λ的极大似然估计又由(2.2.1)式知，是来自均值为λ的指数分布的次序统计量记则有又由引理2.2.1，若又、r，长，乞=1，2，…，n，则有(1)2 。。

Weibull distribution is widely used as a life distribution, and estimating lower confidence limit of reliability is important. But so far this problem has not been well solved if when the sample size is small.

威布尔分布是使用非常广泛的寿命分布，关于威布尔分布的可靠度的下限估计是一个有重要意义的问题，文献中有很多讨论，但当样本量较小时，关于二参数威布尔分布的可靠度的下限估计至今没有非常有效的方法。

The application of the lattice Boltzmann method in unsteady open channel flows was studied in detail in the paper. An existing lattice BGK model was mended; For the problem of negative local equilibrium and evolutionary distribution, we proposed a lattice Boltzmann model based on cell-population equilibrium, which is a direct non-negative approximation to the continuous Maxwell distribution. The model reduces the transport and collision, two basic evolution steps in the LB model, to transport of the non-equilibrium distribution.

本文系统的研究了格子Boltzmann 方法在明渠非恒定流中的应用问题，改进了一个现有的LB 模型，数值实验表明此改进是有效的；在平衡态分布函数及分布函数的非负性问题上，作者提出了一个基于单元均衡的格子Boltzmann 模型，通过直接对Maxwell 分布函数的离散化实现对速度分布函数的非负离散，这种方法将传统模型演化过程中的碰撞和输运两个步骤直接表现为粒子的输运。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。