随机环境SMDP的弱收敛逼近

在随机环境半马氏决策过程的计算方法中，直接从最优方程求最优策略或求ε最优值函数都会遇到困难，本文讨论的弱收敛逼近提供解决这类问题近似计算的一种方法。     

管道清污问题初探

求一般管道系统的最优清污方案,已知这是一个NP难度问题。本短文仅对网络是树的情况,给出求最优清除方案的方法。     

特殊类型线性规划问题的简便解法

本文介绍两种求特殊类型线性规划问题最优解的简便方法——检验框法和电路法．采用这两种方法将大大缩短求最优解的时间，特别是“电路法”有实用价值．     

基于非线性规划一维搜索的煤矿最优安全投资决策分析

传统理论确定煤矿最优安全投资的主要方法是用函数表示煤矿的安全投资与效益的函数关系,再用回归方程、求极值或边际办法等求得煤矿的最优安全投资。由于大多数煤矿的安全投资与效益的关系并不能用函数关系式表示出来,这时就不能使用传统方法来求最优安全投资。基于非线性规划求最优解的复杂性,运用一维直接搜索优化法和斐波那契法的基本思路和理论,求解煤矿的最优安全投资。该种方法适用于不能用函数关系表示煤矿的安全投资与效益之间的关系时,如何确定煤矿的最优安全投资问题,可以确保煤矿在若干年内就能寻找出本企业的最优安全投资量。该种方法依据有理论可靠,可操作性强,省时、省力和省财力。     

非线性优化中关于鞍点及对偶问题的研究

讨论了非线性优化中Lagrange函数的鞍点与原问题和对偶问题的最优解之间的关系,并对对偶理论中的一些性质给予详细证明.对于凸规划在一定约束规格下鞍点总是存在的,可以通过求解鞍点问题来求最优解.最后给出在不等式约束条件下求鞍点的一个迭代方法.     

动态规划的正向递推方法

动态规划求最优解是一个反向递推的求解过程，以实例为依据，用正向递推的方法求解动态规划的最优值，并推出动态规划的基本方程和密尔顿-雅可比方程，是对动态规划求最优解方法的探讨。利用动态规划的正向递推方法，在应用中可以大大减少计算量，扩大了它的应用范围。     

模糊线性规划的最优解分析

在一定条件下,给出了模糊线性规划约束条件伸缩指标向量改变时最优解满意度增量的表达式,并分析了求最优解的方法.     

时变OFDM稀疏信道估计中最优导频选择

针对时变OFDM系统中基于压缩感知的频率选择性衰落信道估计,为了提高其估计精度,结合最优导频选择方式,给出一种自适应求最优导频方法。通过闭环反馈信道稀疏度变化的方式,实时的求取最优导频进行信道估计,并与周期性求最优导频方法进行对比分析。仿真结果表明,自适应方法具有更低的信道估计均方误差,与随机方式相比,性能增益平均提高了11 dB,比周期性方法,平均提高了4 dB,且自适应方法误差曲线更平滑。     

一种新型可靠性模型参数优化求解方法

对可靠性增长模型参数进行求解多采用构造极大似然函数,并对似然函数求极值的方法。用极大似然法进行参数优化估计时,有容易受迭代初值的影响不易收敛到全局最优解的缺点,文中采用进化规划（EP）算法,建立以适应函数为目标,求其极大值点即可确定参数最优解的优化模型,不再需要求极值和估计优化变量的初始值即可获得全局近似最优解。为了更好地确保获得全局最优解,进一步保证方程解的精度,进化规划算法采用了并行操作、保留最优个体等方法。新的优化参数求解方法可以在求解效率和收敛性能上达到较好的平衡,能更好地将优化方法与最大似然估计法相结合。最后利用某固体火箭发动机的可靠性增长实验数据验证了该优化方法的有效性和正确性。     

求非线性规划全局最优解的一个算法

首先给出了判别f（x）的极小值点x0∈D是否为f（x）的最优解的充分必要条件（D为Rn中的闭区域）;在此基础上,给出了求一元函数及多元函数全局最优解的方法．此外,还给出了求一元函数极值的一个迭代算法．     

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。     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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     

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