基于先验的贝叶斯先验选择方法

在一个参数的可选先验类中选择一个合理的先验问题,类似于从参数空间中估计一个恰当参数的问题.基于这一观点,利用贝叶斯分析的后验分布理论,先得出先验的后验分布计算方法,再根据先验的后验分布确定出合理的先验,从而建立了一个基于先验的贝叶斯先验选择方法,它是ML-Ⅱ先验的一个拓广.     

基于参数的贝叶斯先验选择方法

在一个参数的可选先验分布类中选择一个合理先验的问题，类似于从参数空间中估计一个恰当参数的问题．基于这一观点，利用贝叶斯分析的后验分布理论，先求出参数的后验分布，再根据后验分布中各个先验的相对似然选取似然最大的先验为合理先验，从而建立了一个基于参数的后验分布的先验选择方法，它是ML-Ⅱ先验的一个拓广．     

贝叶斯分析中先验分布优选的方法

在一个参数的可选先验分布类中选择一个最优先验密度的问题,类似于从参数空间中估计一个恰当参数的问题,或类比为从决策类中选择出最优决策的问题.从这一角度出发,就可以借助统计学中已有方法,建立一套关于先验分布选取的合理方法,同时能估计其精度.     

贝叶斯分析中先验分布优选的方法

在一个参数的可选先验分布类中选择一个最优先验密度的问题,类似于从参数空间中估计一个恰当参数的问题,或类比为从决策类中选择出最优决策的问题.从这一角度出发,就可以借助统计学中已有方法,建立一套关于先验分布选取的合理方法,同时能估计其精度.     

ε-代换类先验的贝叶斯稳健性

考查了ε-代换类先验的贝叶斯稳健性，衡量其稳健与否的标准是先验为ε-代换类的后验分布的kullback-leibler散度和它的曲率。给出了多维和非共轭情况下后验的kullback-leibler散度的曲率的变化范围。     

不同先验信息下成功概率的Bayes估计

参数的Bayes估计取决于先验分布和损失函数。在平方损失下,参数的Bayes估计是后验分布的均值。在无信息先验、Jeffreys先验和平方损失下,给出两点分布成功概率的估计,比较了其无偏性、方差、均方误差与风险,并进行了数值仿真实验。结果表明:无信息先验分布下的估计优于Jeffreys先验分布下的估计,无信息先验分布下估计的均方误差小于Jeffreys先验分布下的估计的均方误差,无信息先验分布下估计的风险小于Jeffreys先验分布下的估计的风险。     

多级评分的Bayes估计

对多级评分的测验题型,给出了其Bayes模型,把先验分布从无信息先验推广到了更一般的Dirichlet先验分布情形,求出了参数的Bayes估计,指出了其意义,并在不同样本条件下给出了先验分布超参数的估计.     

维修性小子样验证中先验信息的融合方法

研究了在Bayes小子样验证方法中多源先验信息的融合问题。由于维修时间取值具有跳跃性大、范围较宽的特点,采用随机加权法将先验信息表示为先验分布。分别提出了基于均值和基于样本量的先验分布权重因子,在此基础上,建立了基于质量因子计算先验分布权重的模型。通过计算综合先验分布与假设的正态分布的概率密度误差,对其融合后为正态分布的假设进行了检验,同时也提出了准确计算分布模型参数的方法。通过某舰船装备维修性先验信息融合的实例表明了方法的有效性及准确性。     

一次性作用产品可靠度的Bayes置信下限

针对高价值一次性作用产品的小样本可靠性评估问题,选用带有k因子的先验分布,基于贝塔分布的双层先验分布,以及基于均匀分布的双层先验分布,研究了一次性作用产品的可靠度置信下限的估计方法.由模拟研究得出,在有历史数据时,基于k因子贝塔先验分布的估计方法比WCF方法精确;在有不完全历史信息时,基于贝塔双层先验分布的方法比基于均匀双层先验分布的方法精确.     

复合Mlinex损失下艾拉姆咖分布参数的Bayes估计

在复合Mlinex对称损失下,就参数的先验分布分别为共轭先验、无信息先验以及Jeffreys先验,研究艾拉姆咖分布参数的Bayes估计.通过数值模拟得到Bayes估计值并进行了比较,结果表明当先验分布为共轭先验时,Bayes估计值最优,最后的实证分析证明了模拟的结果.     

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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