基于非线性时滞系统与时滞相关的H_∞控制

考虑非线性时滞系统的H∞控制,并对非线性项给出了一个新假设,在其假设下利用线性矩阵不等式方法得到了与时滞相关的H∞控制,同时也得到了该类非线性时滞系统鲁棒镇定的充分条件.     

一类非线性中立型时滞系统的鲁棒H∞控制

研究了一类带有非线性摄动的中立型时滞系统的鲁棒H∞控制问题,时滞是时变的,非线性摄动满足全局Lipschitz条件.通过所构造的新的Lyapunov-Krasovskii泛函,依据Lyapunov稳定性定理,设计一个线性无记忆的状态反馈控制器,使得相应的闭环系统在非线性摄动存在情况下是稳定的,且满足H∞性能指标,并基于线性矩阵不等式(LMI)方法,求解相应问题.     

一类带有非线性摄动的时滞系统的鲁棒H∞控制

基于稳定性理论,该文研究了一类带有非线性摄动的时滞系统的H∞性能问题.通过构造Lyapunov函数推导出一个线性矩阵不等式,从而得到该系统具有H∞性能的充分条件;同时,通过求解这个线性矩阵不等式,即可获得鲁棒H∞控制器.给出系统具有H∞性能的两类时滞相关鲁棒稳定控制器.     

非线性时滞切换系统的鲁棒H_∞控制

在线性常见系统稳定性结合实际智能应用的基础上,研究了一类非线性时滞切换系统的鲁棒H∞控制问题.利用共同的Lyapunov函数、Schur补引理和凸组合技术,给出了由线性矩阵不等式表示的使闭环系统渐近稳定且满足鲁棒H∞性能的一个充分条件;该结果对一类线性时滞切换系统的鲁棒H∞性能也成立,能有助于解决控制器的设计问题,从而应用于实际.     

一类非线性系统的基于观测器的H∞输出反馈设计

某些非线性系统可以通过全局线性化方法 ,转化为线性时变系统 ,因而可通过研究全局线性化后的线性时变系统来处理非线性系统的相关问题 .基于这一思路 ,利用线性微分包含的概念 ,对一类可化为多胞型线性微分包含的非线性系统 ,给出其基于观测器的 H∞ 输出反馈设计方法 ,得到的反馈控制律能使闭环系统内稳且具有 H∞干扰衰减 .文中对双边投影引理和 Finsler引理进行了扩展 ,从而可以处理基本矩阵不等式中块对角矩阵的消去问题 .利用这一结果 ,把基于观测器的H∞输出反馈设计的一充分条件化为线性矩阵不等式 ( LMI) ,进而利用已有的 LMI工具箱对控制律进行求解 .从而避免了采用非线性系统设计的一般方法时必须面对的求解 Hamilton- Jacobi不等式或等式方程的困难     

一类基于T-S模糊模型的非线性广义系统的鲁棒H_∞控制

目的解决一类时滞T-S模糊广义系统的鲁棒H∞控制问题.方法利用Lyapunov函数方法、矩阵缩放理论以及线性矩阵不等式(LM I)技术研究了一类基于T-S模糊模型的非线性广义系统的鲁棒H∞控制.结果首先给出了基于观测器的H∞控制器存在的充分条件,保证了闭环系统是容许且具有H∞性能.通过矩阵缩放理论把这个充分条件表示成了线性矩阵不等式形式,得到了H∞控制器设计方法.结论在系统状态未知并且具有时滞和干扰情况下,所提出的方法很好地解决一类基于模糊模型的非线性广义系统的鲁棒H∞控制问题,通过一个数值算例说明了所提方法的有效性和可行性.     

一类非线性系统的基于观测器的H~∞输出反馈设计

某些非线性系统可以通过全局线性化方法 ,转化为线性时变系统 ,因而可通过研究全局线性化后的线性时变系统来处理非线性系统的相关问题 .基于这一思路 ,利用线性微分包含的概念 ,对一类可化为多胞型线性微分包含的非线性系统 ,给出其基于观测器的 H∞输出反馈设计方法 ,得到的反馈控制律能使闭环系统内稳且具有 H∞干扰衰减 .文中对双边投影引理和 Finsler引理进行了扩展 ,从而可以处理基本矩阵不等式中块对角矩阵的消去问题 .利用这一结果 ,把基于观测器的 H∞ 输出反馈设计的一充分条件化为线性矩阵不等式 (L MI) ,进而利用已有的L MI工具箱对控制律进行求解 .从而避免了采用非线性系统设计的一般方法时必须面对的求解 Ham ilton- Jacobi不等式或等式方程的困难 .     

不确定非线性时滞系统的鲁棒H∞控制

目的分析一类不确定非线性变时滞系统,探讨该系统具有H∞性能的条件以及如何设计其H∞控制律。方法构造了Lyapunov泛函,通过适当地放大不等式,利用矩阵Schur-补的性质,将问题转化为线性矩阵不等式的求解问题。结果对给定的若干常数,若线性矩阵不等式有可行解,则系统具有H∞性能,并由线性矩阵不等式的解阵得到状态反馈H∞控制律,进一步给出了H∞控制律的设计方法。结论通过线性矩阵不等式来判断系统是否具有H∞性能和设计其H∞控制律,方法简便,并且得到的结果比已有结果更具有一般性。     

一类非线性随机不确定系统的鲁棒滤波

研究了满足下列条件的一类非线性随机不确定系统的鲁棒H∞滤波问题：假设系统的线性部分的参数矩阵带有不确定性,且不确定参数是时变范数有界的,而非线性项在原点处满足一致Lipschitz条件,外部干扰是一个随机过程. 通过线性矩阵不等式,给出了该系统的鲁棒H∞滤波器存在的一个充分条件,最后给出一个实例说明此方法的可行性.     

一类非线性系统的H∞观测器的设计方法

研究了一类非线性系统(T-S模糊系统)的H∞观测器设计向题.在对象初始状态不确定情形下,提出一个改进的H∞性能指标,并以线性矩阵不等式(LMI)形式给出了观测器设计方法.     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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-