一种新搜索技术下的CD共轭梯度法收敛性研究

介绍了一种新搜索技术的背景,证明了CD共轭梯度法在这种搜索技术下全局收敛,进而在理论上推广了CD共轭梯度法.     

一种新线性搜索下的共轭梯度法

文章给出了一种新的非精确线性搜索下的共轭梯度法,说明了在新线性搜索下每次迭代能够产生下降方向.证明了新线搜索下FR共轭梯度算法的全局收敛性.     

MWWP线搜索下的新共轭梯度法

随着计算机技术的革新和生产生活中大规模无约束优化问题的涌出,为寻求高效快速的方法,本文构造新共轭梯度算法.将一种修正弱Wolfe-Powell线搜索称为MWWP线搜索,使其与具有良好的充分下降性的DPRP共轭梯度法相结合,证明了该算法在新型线搜索下的全局收敛性,并将该算法与传统共轭梯度法进行了数值实验对比,数值实验结果表明了新方法是有效可行的.     

新Armijo线搜索下的FR共轭梯度法及其收敛性

描述了一种在新Armijo线搜索下的Fletcher-Revees(FR)共轭梯度法,并分析了其收敛性,从理论上证明了借助新的Armijo线搜索,FR共轭梯度法不仅可保证在每步迭代中都容易找出步长,而且可保证全局收敛性.     

Wolfe线搜索下的修正FR谱共轭梯度法

对无约束优化问题的谱共轭共轭梯度法,提出修正的FR共轭参数和谱参数,使每次迭代均自行产生下降方向,且这一下降性不依赖于任何线搜索条件。在常规假设下,证明了采用Wolfe线搜索的新算法具有全局收敛性。相关的数值实验结果表明该谱共轭梯度法是有效的。     

一种线搜索下三项共轭梯度法的全局收敛性

文章〈Hestenes-Stiefel共轭梯度法的全局收敛性〉中提出一新型线搜索条件,根据这一新型的线搜索条件以及一般三项共轭梯度法的方向计算公式,证明了一般三项共轭梯度法在这一线搜索下的全局收敛性.     

结合广义Armijo步长搜索的一类记忆梯度算法

给定记忆梯度算法搜索方向中的参数一个假设条件,从而确定它的一个取值范围,使其在此范围内取值均能得到目标函数的充分下降方向,由此提出一类新的记忆梯度算法.在去掉迭代点列有界和广义Arm ijo步长搜索下,讨论了算法的全局收敛性,且给出了结合形如共轭梯度法FR,PR,HS的记忆梯度法的修正形式.数值实验表明,新算法比Arm ijo线搜索下的共轭梯度法FR、PR、HS和记忆梯度法更稳定、更有效.     

在Armijo线搜索下WYL方法的全局收敛性

提出一种新Armijo型线搜索,并证明了在此搜索下一种新共轭梯度算法具有全局收敛性.新Armijo型线搜索能够使新的共轭梯度算法找到合适的初始步长,从而使它能够更好地运行.数值试验表明在新Armijo型线搜索下的该方法是有效的.     

结合Armijo步长搜索的一类新记忆梯度算法及其收敛特征

对于求解无约束规划的共轭梯度算法中的共轭梯度方向参数 ,给定一个假设条件 ,确定它的一个取值范围 ,以保证搜索方向是目标函数的充分下降方向 ,由此提出了一类新的记忆梯度算法。在去掉迭代点列有界和Armijo步长搜索下 ,讨论了算法的全局收敛性 ,同时给出了结合FR、PR、HS共轭梯度算法的修正形式。数值实验表明 ,新算法比Armijo步长搜索下的FR、PR、HS共轭梯度法更稳定、更有效。     

在非单调线搜索下的CD共轭梯度法的收敛性

对CD共轭梯度法给出一种新的非单调线搜索方法,并证明了在这种非单调线搜索方法下能保证原CD共轭梯度法的全局收敛性.     

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