探讨使用野外随机取样推断随机变量概率分布的数学方法——杂草研究作为一个例子1

我们在生态学研究中涉及到的大多数变量呈现出随机性,因而可以认为它们就是随机变量。概率分布是研究随机变量变化规律的基础,如何利用野外取样来推断检验随机变量的分布是本文要解决的主要问题。本文扩展了回归方法的应用,使其能用来推断一个随机变量的分布函数,并且该推断还能被统计检验。作为一个应用实例,该方法被用于确定杂草种子在特定条件下扩散的分布函数。在此条件下,该杂草种子扩散为近似的高斯(正态)分布。     

探讨使用野外随机取样推断随机变量概率分布的数学方法--杂草研究作为一个例子

我们在生态学研究中涉及到的大多数变量呈现出随机性,因而可以认为它们就是随机变量.概率分布是研究随机变量变化规律的基础,如何利用野外取样来推断检验随机变量的分布是本文要解决的主要问题.本文扩展了回归方法的应用,使其能用来推断一个随机变量的分布函数,并且该推断还能被统计检验.作为一个应用实例,该方法被用于确定杂草种子在特定条件下扩散的分布函数.在此条件下,该杂草种子扩散为近似的高斯(正态)分布.     

探讨使用野外随机取样推断随机变量概率分布的数学方法--杂草研究作为一个例子

我们在生态学研究中涉及到的大多数变量呈现出随机性，因而可以认为它们就是随机变量。概率分布是研究随机变量变化规律的基础，如何利用野外取样来推断检验随机变量的分布是本文要解决的主要问题。本文扩展了回归方法的应用，使其能用来推断一个随机变量的分布函数。并且该推断还能被统计检验。作为一个应用实例。该方法被用于确定杂草种子在特定条件下扩散的分布函数。在此条件下，该杂草种子扩散为近似的高斯(正态)分布。     

广义n重独立试验概型

对于n重Bernoulli试验概型,一些文献对它进行了推广,但都只是从减弱其定义中某一个条件出发而加以讨论的。例如,〔1〕、〔2〕、〔3〕、〔5〕中指出,将Bernoulli试验结果的对立性减弱为“每次试验的可能结果为有限个:A_1,A_2,…,A_m”,其它条件不变,就得到n重独立试验概型,同时还给出了有关这种多项分布概率计算的多项公式;〔4〕、〔5〕、〔6〕等中提到,将Bernoulli试验同一结果在各次试验中出现的概率保持不变减弱为“同一结果在各次试验中出现的概率与试验的次数有关”,其他条件不变,就得到广义Bernoulli试验概型。本文在试验次数为有限的情形下,对Bernoulli试验概型作最宽的推广,提出广义n重独立试验概型,给出有关概率计算的表达式,并且推求出刻划这种概型概率分布的特征函数和主要数字特征。 先给出试验的独立性的定义。     

一类 L-Fuzzy邻近空间的一致结构

在〔6—9〕中,我们运用L-相重的概念,讨论了L(?)Fuzzy 邻近空间的若干性质,显示了这种定义的自然性,它以通常意义的邻近空间及由A.K.Katsaras 定义的Fuzzy 邻近空间(见〔2〕〔3〕)为特款,而又避免了出现病态的性质.关于L(?)Fuzzy 一致结构性质的讨论,由于在〔4〕,〔5〕等文中得出了关于保并映射的交运算、逆运算的较深入的结果,近年来受到国内外的Fuzzy 拓扑同行的重视.在〔9〕中,我们运用这些结果曾证明L(?)Fuzzy 一致空间具有某种自然的L(?)Fuzzy 邻近关系.本文考虑其反面的问题.我们将再次运用〔4〕,〔5〕中的重要结果,对于一类L(?)Fuzzy 邻近     

缓变系数线性中立型系统的稳定性

文〔1〕研究了缓变系数动力系统的稳定性。文〔3〕、〔4〕利用〔1〕中方法讨论了中立型微分系统的稳定性,但是附加了初始函数φ(t)的二阶导数φ(t)存在且有界的条件。这样就缩小了初始数据空间,因为中立型系统的初值问题只要初始函数φ连续一阶可微(可参见〔2〕)。本文改进了〔3〕的结果,取消了φ(t)存在的限制,在其它条件与〔3〕、〔4〕相同的情况下,得到了稳定性结论。     

人工草地羊草种群生态的研究

本文从种群生态水平,探讨了在人工管理,而且连年刈草这一特定生态环境下,羊草种群的数量变化,空间分布格局及其种子生产动态。在人工控制其它杂草竞争的条件下,播种当年每平方米仅有10～30株幼苗的羊草种群,通过无性繁殖其数量在第二年出现急剧增长,第三年和第四年增长的速度逐年减缓。羊草所依靠其无性繁殖特性,使个体呈群聚型分布,但在单优种群落中,又容易呈高密度的随机分布。连年刈草对羊草种群的种子生产有严重影响。     

L—Fuzzy一致空间的邻近结构

在〔6〕中,运用L—相重的概念,我们给出了L—fuzzy 邻近空间的定义,并证明L—fuzzy正规空间,拟度量空间是L—fuzzy 邻近空间,接着,在〔7〕,〔8〕中,我们讨论了L—fuzzy 邻近空间的拓扑性质,显示了这种定义的自然性,它以通常意义的邻近空间及〔3〕,〔4〕等文中Katsaras 定义的fuzzy 邻近空间为特款。     

向量极值解的必要条件

本文在Banach空间中,对非常一般的广义凸性条件,给出了择一定理、向量极值的拉格朗日乘子定理、鞍点定理和对偶定理等内容,这些结果推广了文献〔1〕〔3〕〔4〕中许多结论。     

FUZZY半测度与FUZZY测度

Fuzzy 可测集与 Fuzzy 测度的概念肇始于 L.A.Zadeh 在〔1〕中提出的 Fuzzy 事件与 Fuzzy 概率测度。七十年代 M.Sugeno 在〔2〕中从另一途径建立了不必具有可加性的一种 Fuzzy 测度与Fuzzy 积分理论。最近,E.P.Klement 与 W.Schwyhla 在〔3〕与〔4〕中给出了 Fuzzy 概率测度与有限 Fuzzy 测度的积分表示定理。何家濡在〔5—8〕中从严格的公理系统出发,建立了 Fuzzy测度空间、Fuzzy 概率空间以及(正规)Fuzzy 半测度空间,而且在〔9〕中发展了半测度的概念,提出了建立和扩张测度的另一种非传统的框架,同时在此半测度的框架下建立了 S 型积     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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