非线性l1问题的一种解法

本文对非线性l1问题minx∈RnF(x)=∑mi=1|fi(x)|,从理论上研究了F(x)的下降方向、最优解与某种盒式约束最小二乘问题的最优解之间的关系,进而构造了一个非线性l1问题的下降算法,并证明了该算法的收敛性.数值例子说明所给的非线性l1问题的下降算法是有效的.     

引入二阶导数的梯度法

对最优化方法中的梯度算法进行了改进．当2f/x2=≠0时，将二阶导数与梯度方向相结合，构造出一种新的下降方向d=[1＋δ／（2f／x2）]（f／x），其中δ=1或-1．用新的下降方向设计了一种算法，使梯度法得到改进．新的算法比梯度法的收敛速度快，而且比牛顿法计算量小．     

Steffensen迭代加速法的改进

证明了加速迭代x_(x+1)=g(x_n)收敛的Aitken技术,实质上是求解z-g(x)=0的线性插值法.由此可简洁地研究Steffensen法的性质,并证明将弦割法应用于方程x-g(x)=0,可得出比Steffensen法更有效的加速迭代收敛的算法.     

变分不等式问题的法方程解法

研究了变分不等式问题的法方程解法 .在一般可行集下 ,结合非光滑方程组解法及投影映射的性质 ,讨论了法方程求解变分不等式问题的算法构成 .结果表明 ,在变分问题解x 处 ,法方程FX(x)强BD 正则 ,算法局部收敛     

一种求解GF(2m)上2,3次多项式根的快速查表算法

对BCH码和RS码解码时,常用Chien搜索法或直接查表法求取GF(2m)上错误位置多项式σ(x)的根.随着m增大,搜索次数或查找表容量以2的m次幂迅速增长,使求根过程的时间或空间开销大大增加.当m较大而σ(x)的次数较低时(如2或3),采用这些方法尤其不理想.为此研究了GF(2m)上2次错误位置多项式x2 ax b和3次错误位置多项式x3 ax2 bx c根的快速查表算法,该算法简化了前述多项式的原始求根表,理论分析表明它比直接查表法明显节省存储容量;比Chien搜索法明显加快求根速度.     

优化模型的变换求解及其反演

人们介进行工代优化时,注意到了两个环节:首先建立优化的数学模型,接着选择适当的数学规划方法求解。然而二者之间还有一个环节往往被忽视了,这就是将数学模型进行变换处理然后求解。例如下面一个简单的问题: 如果采用最速下降法求解,不难推得其中 当初始点不在x1轴亦不在x2轴上时,搜索路径为一锯齿形,从理论上讲,由初始点走到最优点x*=[00]T,需要走无穷步。Newton-Raphson算法则只走一步。限制合一阶算法范围内,能否一次走到最优点呢?乍看起来似乎不可能。其实只要引进变换。z1=x1,,问题则化为. 用最速下降法,不管初始点取什么值,一步便…     

RL型蕴涵与Fuzzy推理的三Ⅰ算法

引入了RL型蕴涵与正则RL型蕴涵的概念,系统地讨论了基于RL型蕴涵的三Ⅰ算法、三I MT算法及其还原性,得到了这些算法的一般表达式,指出基于正则RL型蕴涵的三Ⅰ算法与三ⅠMT算法的表达式具有对偶形式;证明了当P表示条件{B(y)| y∈Y}(∩){A(x)| x∈X}时,基于RL型蕴涵的三I算法为P-还原算法,当P表示条件{A(x)| x∈X}(∩){B(y)| y∈Y}时,基于RL型蕴涵的三I MT算法为P-还原算法.     

一个新的非单调自动确定信赖域半径的信赖域算法

将非单调线搜索技术与自动确定信赖域半径的方法相结合,提出了求解无约束优化问题的一个新的非单调自动确定信赖域半径的信赖域算法.在假设对任意x1∈Rn,水平集L(x1)={x|f(x)≤f(x1)}有界,且目标函数f(x)在水平集L(x1)上连续可微;矩阵序列{Bk}一致有界的条件下证明了本算法的全局收敛性.数值结果显示本算法是有效的.     

一个基于函数值平均权重的新的非单调自适应信赖域算法

将一种基于函数值平均权重的非单调线搜索技术与自动确定信赖域半径的方法相结合,提出求解无约束优化问题的一个新的非单凋自动确定信赖域半径的算法.在假设H∶A.对任意的x1∈Rn,水平集L(x1)={x∈Rn|f(x)≤f(x1)}有界;B.在水平集L(x1)={x∈Rn|f(x)≤f(x1)}内,目标函数f(x)的梯度函数g(x)满足Lipschitz条件;C.矩阵序列{Bk}一致有界及其它条件下证明了本算法的全局收敛性.     

求解方程近似解的改进双曲线型迭代算法

应用双曲线逼近法,在分析了迭代算法思想的基础上,结合过程模拟与系统仿真的实际,推导出求解方程f(x)=0近似根新型迭代算法,并给出了迭代格式和计算方法.计算结果表明,用此算法求解方程的根,收敛速度及稳定性均好于割线法,初值选取范围比牛顿法和割线法宽.此算法的提出对于方程求根的理论分析和工程应用都有十分重要的意义.     

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