执行器故障检测的神经网络观测器方法

针对一类非线性系统,提出了一种用于执行器故障检测的神经网络观测器方法·这种非线性系统具有未知非线性函数,不需要满足结构匹配条件,并且不要求系统状态可测·观测器利用神经网络器逼近系统中的未知非线性项,提高了状态估计的精度·估计的残差提供了故障检测的手段,另一方面利用自适应律进行故障的识别·基于李亚普诺夫方法,从理论上证明了状态估计误差稳定且渐近收敛到零·最后,仿真结果表明该方法的有效性·     

工程机械驾驶员座椅主动悬架最优控制

建立了车辆座椅两自由度悬架系统的力学和数学模型,应用线性随机最优控制理论(LQG),根据路面随机振动输入的统计特性,在状态变量不全知的情况下,通过Kalman-Bucy滤波器对其进行无偏最优估计,设计出控制系统的最优反馈规律·应用MATLAB仿真语言对该模型进行编程设计和计算机仿真实验·     

G-BP算法在烧结矿FeO指标预测中的应用

实现烧结过程工艺参数的优化,首先要进行烧结矿质量预测·采用遗传算法与BP神经网络相结合的方法,建立了烧结矿FeO含量预测模型,并改进BP学习算法·仿真表明,该方法可以优化神经网络结构,缩短学习时间·与传统的BP神经网络模型相比,预测值与实际值间的相对误差由6534%降低至1400%,其精度高于传统BP网络模型·该方法为实现在线预测奠定基础·     

我国证券市场有效性实证分析

运用序列相关性和游程检验方法,对我国股票市场的有效性进行了检验,上海股票市场利用上证综合指数周末收盘价(19951222～19990408),深圳股票市场利用深证综合指数周末收盘价(19960607～19990408)·两种方法检验结果表明,两个市场均具有弱有效性·在对个股进行检验时,总体所选样本的有效性检验得以通过,与大盘相一致;但个别股票表现出具有一定的价格相关性·这表明,我国股票市场近年来总体发展是趋向于规范而有效的,但其有效程度还不高     

基于小波分析理论的证券投资市场预测

提出了一种基于小波分析理论对证券投资市场建模及其预测的方法·该方法分两步完成:第一步通过小波分解进行数据滤波,将证券价格变化曲线中的高频信息过滤,从而实现消除噪声,提高预测精度的目的;第二步应用最小二乘方法建立数学模型,并用模型进行中、长期证券价格预测·实际股票价格仿真结果表明:此方法简洁、预测效果良好,优于一般最小二乘方法     

证券市场股票收益的GARCH模型

文章利用深圳证券市场的股价指数信息,建立股票收益的GARCH模型,并对该模型的参数、阶数进行估计,分析了股票收益的变化趋势.作为该结果的应用,可以对短期股票收益的变化规律进行预测,对证券市场的投资和管理提供有益的信息及帮助.     

一类具有不确定性的相似组合系统的鲁棒镇定

研究非匹配条件下不确定非线性相似组合大系统,给出其可用结构相似非光滑控制器进行镇定的鲁棒分散控制器设计方案及镇定域的估计方法·这种控制器由线性和非线性部分组成,其中的非线性部分类似于“砰砰”控制,相对于现有结果,新设计的控制器计算量小,比较容易实现·     

不完全2×2列联表中基于置信区间的样本量研究

 使用基于约束性极大似然估计的统计量,对不完全2×2列联表中的风险比进行置信区间构造.导出在一定置信水平下控制置信区间宽度的样本量公式.模拟研究和实例分析验证了所给方法的合理性.     

钢铁企业产成品预报模型

基于某钢铁企业整体产销系统的合同跟踪策略和实现方法 ,利用SAS/EnterpriseMiner软件提供的SEMMA过程 ,对冷轧生产线上产成品的产出规律进行了探索 ,建立了产成品预报的神经网络模型·模型以合同在生产线上最后几道工序的通过日期和通过时间为输入 ,以合同的完成日期为输出·利用SAS/EnterpriseMiner软件提供的神经网络功能进行了大量的试验 ,结果表明神经网络模型是进行产成品预报的有效方法 ,预报精度可达到 91 %以上·试验中也发现 :隐层节点激活函数形式对预测效果有一定影响 ,而隐层节点数对预测效果影响程度较小 ;数据噪声对预测效果有一定的影响     

PMSM神经网络实时IP位置控制

对永磁同步电机 (PMSM )提出了一种基于神经网络的实时IP位置控制方案·根据伺服系统中的IP控制策略 ,利用神经网络的优点设计了神经网络实时IP位置控制器·所设计的神经网络实时IP位置控制器结构简单 ,权值调整计算量小、速度快·同时用混合神经网络作为PMSM系统辨识器 ,用多步预测性能指标函数实现了实时在线训练·理论分析和实验仿真对比研究的结果 ,表明所提出方法具有优越的动态性能和鲁棒性·     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the