电力电子系统控制电路参数离散最优化

将电力电子系统的最优控制问题变换为参数最优化问题。以正激开关稳压电源为例，建立其控制器小信号离散参数最优化模型，应用一种离散非线性规划算法求解。得到在加权ＩＳＥ最小意义下并在工程上可实现的控制器最优参数。用ＳＰＩＣＥ－２仿真，比较了用连续与离散两种非线性优化算法设计的正激开关电源瞬态响应及频率特性．     

基于DSP的异步电动机转子参数自适应控制

针对交流调速系统控制对象多变量、强耦合、非线性的特点,结合非线性微分几何法控制策略,提出转子时间常数最优化的自适应控制算法,结合新的调节器结构和算法,利用TMS320LF2407A为设计平台,应用于异步电动机转子参数的辨识和校正,减小运行过程中转子参数变化对系统的影响,并给出实验测试结果.     

一种QoS感知的服务全局优化选择算法

将服务选择问题建模为带QoS约束的非线性最优化问题,并提出了一种参数自适应的改进遗传算法(IPAGA).构造了基于双曲正切函数的非线性参数变换函数,当迭代次数或种群多样性程度增加时,使遗传算法的交叉和变异概率相应地非线性递减,以保证算法的全局收敛性和收敛速度.实验结果表明:算法能够快速搜索出全局近似最优解,具有很高的有效性和可行性.     

直观模糊特别拓扑空间中的半开集和半连续

将半开集和半连续的概念引入直观模糊特别拓扑空间, 得到它们的一些性质:一个直观模糊特别集是直观模糊特别半开集的充要条件是 A cl[ int(A) ] ; 直观模糊特别半开集族的任意并是直观模糊特别半开集; 直观模糊特别开集是直观模糊特别半开集; ( X,τ)的子空间( ( Y,φ)中的集合 A 是( X,τ)中的半开集,则它也是( Y,φ)中的半开集; 连续函数是半连续的,但逆不成立; 强半连续是半连续的, 但逆不成立;函数 f 是半连续的当且仅当对于f ( x ) O, O 是 Y中的直观模糊特别开集,存在 X 中的直观模糊特别半开集A 使x
A 且f (A ) O; 函数 f 是强半连续的当且仅当 Y中的每一直观模糊特     

一种求解变量有界非线性规划的全局最优解新方法

提出了一种求解变量有界非线性规划的全局最优解新方法——不可行域移除(IRIR)法.在优化过程中,先计算原最优化问题的不可行域,然后在原最优化问题的求解空间中移除确定的不可行域,使得新的求解空间不断缩小,并通过研究不可行域的线性表达,在不影响最优解的前提下将非线性约束转化为线性约束,以求解非线性规划问题,其特点是所得最优解对原最优化问题约束函数的凸性和优化迭代起始点的位置不敏感.同时,阐述了IRIR法的原理和实现过程,在序列二次规划(SQP)算法的基础上,应用数值算例和弹簧设计2个典型实例,以验证IRIR法的可行性和正确性.结果表明:IRIR法可以有效降低原最优化问题的求解难度,且无需引入新参数,是一种具有较高求解能力和实用价值的全局最优化方法,但其不适用于求解设计变量无界的最优化问题.     

关于广义非线性互补问题

研究了广义非线性互补问题．将互补问题转化为一个无约束最优化问题，而最优化问题的全局最优解恰为广义非线性互补问题的解．给出了无约束最优化问题的平衡点是广义非线性互补问题的解的一个充分必要条件和一系列充分条件．文中结论推广了有关文献中的相应结论．     

拟牛顿方法中梯度的一个二次模型

J.A.Ford对于无约束最优化的拟牛顿方法介绍了一种新算法,这种算法是通过对目标函数的梯度构造含有单参数的非线性模型而导出的.本文给出了一个梯度的单参数二次模型,它结构简单,且参数便于计算.     

非线性规划方法简介(Ⅳ)

第六章带非线性约束的最优化问题这一章我们叙述带非线性约束的最优化问题的算法。带非线性约束的最优化问题比线性约束的最优化问题处理起来要困难得多,这方面的算法及有关理论的研究主要是近十多年来发展起来的。大致说来,解决非线性约束的规划问题有这样几种途径:一是把带约束的非线性规划问题变换为若干个或一系列无约束的规划问题,这就可以用无约束的规划问题的方法来解决,例如罚函数方法和障碍函数法;一是把可行方向法和投影法推广到非线性约束的规划问题,这种推广主要是解决由于可行点集的非线性边界带来的困难;一是把非线性约束条件逐次线性化,把原问题归结为解决一系列的线性约束的子规划。此外,还有解非线性约束     

关于广义非线性互补问题

研究了广义非线性互补问题,将互补问题转化为一个无约束最优化问题而最优化问题的全局最优解恰为广义非一互补问题的解,给出了无吵最优化问题的平衡点是广义非线性互补问题的解的一个充分必要条件和一系列充分条件,文中结论推广了有关文献中的相应结论。     

模拟退火法用于电压稳定分析

为了提高用于电压稳定分析的非线性最优化方法的效率,提出了将模拟退火法和单纯形法相结合求解非线性最优化问题的新算法,避免了在全局最优点附近的大量低效搜索,提高了模拟退火法的计算效率。应用这种新算法求解静态电压稳定极限,用５节点系统进行验证得到了满意的结果。求解静态电压稳定极限问题可以等效为含有非线性等式约束和不等式约束的非线性最优化问题,采用内点法将不等式约束问题转化为等式约束问题,再通过引入罚函数转化为无约束最优化问题,然后应用本算法进行计算,结果表明新算法是有效的。     

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.     

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