求线性规划初始基可行解的两种新算法

众所周知，用单纯形法求解线性规划问题时，首先要找到一个初始可行基．当线性规划问题无明显可行基时，通常要引入人工变量，采用大Ｍ法或二阶段法来求解．由于人工变量的引入，变量数增加，计算量和计算机的存贮量也随之增大．因此，不少作者〔１，２〕对求线性规划初始基可行解的方法进行研究，以提高求解效率．本文给出了两种求线性规划问题初始基可行解的新算法，从数值例子来看是高效率的．考虑如下的线性规划问题ｍａｘＺ＝ＣＴＸＳ．ｔ．　Ａｘ＝ｂ　ｘ≥０，（１）其中Ｃ，ｘ∈Ｒｎ，ｂ∈Ｒｍ，Ａ∈Ｒｍ×ｎ．假定ｂ≥０，ｒｎａｋ…     

一种求线性规划问题初始基可行解的方法

提出了一种在不引入人工变量的情况下，寻求线性规划初始基可行解的方法，与传统的两阶段法相比，具有计算量小且占有存储空间少的特点，对两阶段法第一阶段问题作了改进。     

关于线性规划的几个问题

本文改正与补充了参考文献[1]与[2]中有关退化基可行解、求初始对偶可行解、求线性规划问题全部最优解以及分配问题算法的有限步收敛性等四方面的一些论断,给出了正确的结果。     

解线性规划问题的一种半单纯形法

本文提出解线性规划问题的一种方法，主要是对约束Ａｘ＝ｂ求初始基可行解时，不必引入人工变量而可直接用旋转运算获得，之后就完全和单纯形法一样求最优解，并提出了判定无可行解的方法和准则，对算法的理论问题也作了证明和解释。     

一种改进的单纯形最优化方法

对求极小化线性规划问题max Z=CX,AX=b,x≥O,通过添加人工变量,可直接获得问题的基解,若求得问题的基解不是原问题的可行解,也不是对偶问题的可行解的情况下,本文给出了求解该类规划问题初始可行解的一般方法.     

线性规划问题的一种改进的单纯形法

提出了一种求解线性规划问题的方法,即对约束Ax=b求初始基可行解时,不必引入人工变量而直接用旋转运算获得,之后利用传统单纯形法求最优解,并给出了该方法的实算例子.     

寻求线性规划问题初始基可行解的一种新算法

对线性规划问题基可行解的性质进行了研究，给出了一种求解线性规划问题初始基可行解的算法，该算法的时间复杂度是约束条件个数的线性函数。     

求解初始可行基的算法实现

对于规模较大的线性规划问题,基于矩阵初等变换求初始可行基,判断的过程会比较复杂;由此提出利用Matlab软件对系数矩阵进行初等行变换,通过判断和换基迭代求得初始可行基,简化了求解过程．     

寻求线性规划问题初始基可行解的一种新算法

对线性规划问题基可行解的性质进行了研究，给出了一种求解线性规划问题初始基可行解的算法，该算法的时间复杂度是约束条件个数的线性函数     

0-1多项式背包问题的一种精确算法

提出了0-1多项式背包问题的一种新的精确算法. 该算法是一个基于拉格朗日松弛和对偶搜索的分枝定界方法. 用外逼近法求拉格朗日对偶问题得到上界,其中拉格朗日松弛问题通过转化为一个网络最大流问题来求解. 为了提高算法的效率,利用两种启发式方法求初始可行解,并用填充和交换的方法改进后得到初始下界; 并且在分枝定界前, 利用所得到的拉格朗日界, 先固定最优解中某些变量的值. 数值结果表明该算法是有效的.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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