求解非凸函数优化问题的修正广义拟牛顿算法

对无约束最优化问题,提出了一种修正的广义拟牛顿算法,证明了该算法对非凸函数在Goldstein非精确线搜索下具有全局收敛性．     

一类改进的拟牛顿算法

在利用拟牛顿算法求解非线性无约束优化问题中,本文在文献[8]提出的拟牛顿方程基础上,通过加权形式构造一类改进拟牛顿方程,产生了修正的BFGS校正公式,进而提出改进的拟牛顿算法,在一定条件下证明新算法的全局收敛性。数值实验结果表明,与文献[12]中的拟牛顿算法对比,新算法在迭代次数上更有优势。     

拟牛顿算法的收敛特性及算法的拓广

介绍了拟牛顿算法的收敛特性，即算法采用精确线性搜索与非精确线性搜索时具有的全局收敛性与超线性收敛性。这些优良性质使拟牛顿算法类在优化算法中占有极为重要的地位。相关的研究成果十分丰富，这里作一简要介绍及若干算法拓广。     

改进的SR1拟牛顿法的2n步q二次收敛性

为了从理论上证明基于新拟牛顿方程的改进拟牛顿方法比传统的拟牛顿方法有更好的收敛效果，对改进的ＳＲ１拟牛顿方法进行了深入的研究，在变尺度矩阵序列正定有界的条件下，证明了算法在每ｎ＋ｐ（ｐ≥１）步迭代中至少有ｐ步是好的（ｑ超线性步），进而证明了算法的２ｎ步ｑ二次收敛性。     

基于新拟牛顿方程的一类超线性收敛的改进BFGS算法

针对无约束最优化问题,在已建立的一类新拟牛顿方程的基础上,把满足于传统拟牛顿方程的一类改进BFGS算法推广到新拟牛顿方程,从而得到一类基于新拟牛顿方程的改进BFGS算法.证明该算法在目标函数为一致凸时具有局部超线性收敛性.     

基于三阶拟牛顿方程的对角三阶拟牛顿法

基于三阶拟牛顿方程,结合Zhang H.C.提出的非单调线搜索规则设计了求解大规模无约束优化问题的对角三阶拟牛顿算法。该算法在每次迭代中利用对角矩阵逼近Hessen矩阵的逆,使存储量和计算量明显减少,并且证明了算法的全局收敛性和超线性收敛性。数值试验表明该算法是有效的。     

一类拟牛顿算法的收敛性

根据一类基于新拟牛顿方程Bk 1sk=yk*的修改BFGS类算法,采用广义W olfe线搜索模型(GW搜索模型):f(xk 1)≤f(xk) δkαgTkdk和g(xk 1)Tdk≥m ax{,σ1-(kα‖dk‖)p}gTkdk,其中0<δ≤σ<1,p∈(-∞,1),得到一类修正的BFGS算法(M BFGS),证明了M BFGS算法的全局收敛性和超线性收敛性.数值试验结果表明M BFGS算法是有效的.     

基于新拟牛顿方程的拟牛顿法的超线性收敛性分析

假设f（x）二阶连续可微且一致凸时和f（x）的二阶导数矩阵G（x）在极小点x^＊处满足Holder条件，文章证明了基于新拟牛顿方程的拟牛顿法的超线性收敛性．     

拟牛顿非凸族算法的收敛性

对于无约束最优化问题min f(x),x ∈Rn,提出了一类拟牛顿非凸族算法,并结合一类更广泛的线性搜索,在目标函数凸的条件下,证明了算法的全局收敛性.     

一种基于弱拟牛顿方程的单调梯度法的收敛性

基于弱拟牛顿方程,Leong W J等人提出了一种单调梯度法,该算法在每次迭代时利用对角矩阵逼近Hessian矩阵,使计算量和存储量明显减少,并且此算法对凸函数具有收敛性。在此算法的基础上,进一步研究了算法对于一般函数的收敛性,并证明了在一定的假设条件下算法仍具有全局收敛性、R-线性收敛性和超线性收敛性。     

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.     

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.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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