故障估计下子空间预测控制的快速梯度算法

基于闭环系统观测数据,直接设计估计故障和预测控制器.在施加故障的上下限约束条件下,采用快速梯度算法估计故障.在此基础上,采用子空间预测控制策略求解一个带有线性矩阵不等式约束的优化问题.对于故障估计下子空间预测控制的最优化问题,构造了一组估计序列,以采用快速梯度算法求解.直升机悬停状态仿真实例表明,本文方法是有效的.     

实时状态树结构模型的最优非阻塞模块化监督控制研究

针对传统的实时离散事件系统监督控制方法中存在监控器的设计复杂度高、结构不灵活且不易维护的问题,在实时状态树结构模型的基础上,提出了一种实时离散事件系统的最优非阻塞模块化监督控制方法。该方法根据不同的控制任务,将被控系统的性能指标划分为若干个子性能指标的合取形式,并且对每一个子性能指标分别设计子最优非阻塞监督控制器。由这些子最优非阻塞监督控制器构造被控系统的模块化监督控制器,给出了最优非阻塞模块化监督控制器的存在条件;通过设计协调器来解决整个闭环系统可能阻塞的问题。实验结果表明,模块化监督控制方法不但可以有效地降低实时离散事件系统监督控制器的设计复杂度,而且保证所得到的模块化监督控制器是最优且非阻塞的。     

子空间预测控制方法在线性变参数系统中的应用

提出了一种针对线性变参数系统的新型子空间预测控制方法。该方法首先通过子空间辨识算法获得线性变参数系统的子空间预测输出。然后,对构造的输入输出矩阵进行QR分解得到子空间预估器,将子空间预估器用于设计模型预测控制器。该控制器包含了积分作用,可消除稳态误差。最后,通过风机扑翼动力学系统的仿真实验,证明了该方法的有效性。     

广义T-S模糊系统的非脆弱保代价控制

对于给定的系统,在控制器存在可加摄动的情况下,通过并行分配补偿的方法设计了状态反馈最优保代价控制器,使系统不仅渐近稳定而且具有最小性能指标上界.基于线性矩阵不等式处理的方法,给出了该控制器存在的充分条件;通过建立和求解一个凸优化问题,给出最优非脆弱保代价控制器的设计方法,最后通过算例显示了所给方法的有效性.     

一类串级非线性系统的最优滑模控制器设计

对一类串级不确定非线性系统提出了一种基于SDRE控制的最优滑模控制方法.该方法采用2环控制结构，外环控制器的设计采用基于依赖状态的Riccati方程最优控制器，用以产生最优滑模面；内环控制器的设计采用滑动模控制以减小控制系统对参数变化、模型误差、外部干扰的敏感.设计的最优滑模控制器能使一类串级不确定系统具有鲁棒稳定性.同时，提出了2种求解依赖于状态的Riccati方程的方法.最后，通过仿真实例验证了该控制方法的有效性.     

基于通信的数据驱动分布式预测控制

针对分布式控制系统的特点,提出了一种新型的基于数据的分布式预测控制优化算法。由输入、输出数据直接设计分布式控制器,控制器在各个子系统通信的条件下采用基于纳什最优的分布式控制优化算法,以较低的成本达到整个大系统的性能优化。这种基于数据的方法使传统的预测控制器设计过程中的系统辨识和基于状态空间模型的预测控制简化为直接的一步,即直接利用数据设计分布式控制器。本文给出了这种新型算法的收敛条件,仿真结果证明了该方法的有效性。     

不确定切换时滞线性系统的状态反馈鲁棒H_∞控制

研究一类由任意有限多个具有参数不确定性和状态时滞的线性子系统组成的切换系统的状态反馈鲁棒H∞控制问题,利用Lyapunoy函数方法和凸组合技术,给出由矩阵不等式表示的控制器存在的充分条件,并设计了相应的子控制器和切换规则.采用变量替代方法,将该矩阵不等式转化为一组线性矩阵不等式(LMIs),最后给出一个求解状态反馈控制器增益矩阵的仿真算例.     

基于最优控制的永磁同步电机转速控制

由于永磁同步电机具有非线性和变量之间存在耦合性,为提高永磁同步电机的控制精度与稳定性能,对采用微分几何方法和最优控制器设计问题进行了研究,首先结合永磁同步电机的数学模型对电机转速的理论基础进行了分析,并采用状态反馈精确线性化控制策略,在此基础上,利用二次型性能指标的最优控制器设计方法,求解出系统最优控制率,最后对该方法进行仿真验证,结果表明,该方法可以明显改善系统的动态性能,提高一定的抗干扰能力。     

不确定离散时滞系统的H∞保性能预见控制

针对一类具有凸多面体不确定常参数的离散时间时滞系统,研究其H∞最优保性能预见控制器的设计方法。首先,与以往不同,本文的扩大误差系统仍然保留了时滞,以保证扩大误差系统的状态向量维数不随时滞的增加而增加。其次,针对所构造的扩大误差系统,设计有记忆的状态反馈控制器,并利用线性矩阵不等式方法,导出确保所求控制器存在的条件及该控制器设计的方法。最后,通过建立并求解一个含线性矩阵不等式约束的凸优化问题,给出扩大误差系统的鲁棒H∞保性能控制器,该控制器对于原系统来说就是鲁棒H∞保性能预见控制器。     

数字1型伺服系统的低阶控制器设计

使用滤波型或预测型降阶观测器的控制器被用于数字1型伺服系统的输出反馈设计中,以便降低控制器的阶数,并考虑一拍的运算延迟。该控制器由状态反馈设计和降阶观测器来决定。本文通过导出基于这个控制器的二重互质分解状态空间表达式,获得了所有能保证积分作用并考虑了一拍运算延迟的稳定化控制器的参数化形式,它把稳态特性和运算延迟的要求表达为对自由参数的约束,而且还可以用于求解H_2和H_∞最优灵敏度控制问题。     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-