动态核概率主元分析模型及其应用

核概率主元分析(kernel probabilistic principal component analysis,KPPCA)能够有效去除过程的非线性.但是KPPCA仅构造了生产过程的静态线性关系,处理具有较强动态特性的实际工业生产过程效果较差.为克服上述缺点,提出一种基于动态KPPCA的过程监测方法,利用核函数将经过压缩的动态增广数据映射到高维空间,然后利用PPCA对满足线性关系的过程变量映射值进行监测.仿真结果表明:该方法监测指标对故障的灵敏度高,误报率和漏检率较小,故障状况与正常状况很明显的分离开来.     

基于改进核主元分析的故障检测

针对电主轴系统特点,提出基于改进核主元分析(KPCA)的故障检测方法,引入混合核函数的定义,将多项式核和径向基核的混合核方法与主元分析方法(PCA)相结合,解决采用单一核函数诊断故障时的高误诊率问题.首先对数据进行预处理,然后使用混合核函数对数据矩阵进行映射,映射到高维特征空间,使非线性数据变量变为线性数据变量,并使用PCA提取变量数据的高维空间相关特征确定主元个数,最后根据混合非线性主元特征计算出的T2和Q统计量,实现在线故障检测.该方法改进传统核函数的选取方法,充分考虑工业过程中的非线性,更精确地描述工业过程特性,可以准确、有效地检测出电主轴系统故障.对田纳西-伊斯曼(TE)过程以及电主轴系统的应用实例证明该方法的可行性.     

基于核主元分析的湿法烟气脱硫系统的故障诊断

提出一种基于核主元分析(KPCA)的故障诊断方法,通过提取集成算子与非线性核函数计算后映射到高维空间的主元成分,有效地捕捉过程变量的非线性关系.对华能福州电厂烟气脱硫过程采集的数据进行传感器完全失效、偏差等故障实验仿真,结果表明,KPCA具有很好的故障诊断能力.     

基于等距离映射的非线性动态故障检测方法

针对化工过程数据强非线性和动态性的特点,提出了一种基于动态等距离映射(Dynamic Isometric Mapping,DISOMAP)流形学习的非线性过程故障检测方法.该方法首先采用DISOMAP算法提取训练样本的子流形特征,自适应学习近邻点参数,保留了采样数据的流形结构,然后运用线性回归方法得到原空间和降维子流形空间的投影映射,从而将观测数据从原高维空间映射到低维嵌入空间,最后在变换后的低维空间构造统计量T2和SPE进行监控.TE过程的仿真结果表明,所提出的DISOMAP故障检测方法可以比核主元分析(Kernel Principle Component Analysis,KPCA)更为有效地监控过程变化,检测到故障的发生.     

基于核函数PCA的非线性过程实时监控方法

为了克服基于主元分析的过程监控方法非线性处理能力弱的缺点和降低基于非线性主元分析的过程监控方法的计算复杂度,提出了将核函数PCA监控方法用于复杂工业过程实时监控系统的开发研究,并讨论了核函数参数选择对系统性能的影响。核函数PCA能有效地提取过程变量的非线性关系,而且计算复杂度低,便于在线实施。仿真结果表明该方法是一种有前途的复杂过程非线性实时监控技术。     

基于双核独立元分析的化工过程故障诊断算法研究

由于化工生产过程数据具有强非线性和非高斯性特征,提出了核主元分析与核独立元分析相结合的可用于化工过程故障诊断的双核独立元分析算法,该算法利用核主元分析的非线性核函数把数据从原空间映射到高维特征空间进行白化预处理,再用核独立元分析算法进行独立元分析,在特征空间中获得故障监控统计量,计算控制置信限,达到有效的故障诊断.提出的算法应用在连续搅拌反应釜过程中,结果表明,该算法对化工过程故障诊断能有效提高准确度、降低漏报率和误报率.     

基于核状态空间ICA的非线性动态过程故障检测方法

针对工业过程的非线性和动态特性,提出一种基于核状态空间独立元分析的故障检测方法.采用核规范变量分析法将非线性动态过程数据映射到核状态空间,得到去相关的状态数据.对状态数据的各时延协方差矩阵进行加权求和得到状态数据的时序结构矩阵,进而建立ICA统计模型,从状态数据中提取独立元特征数据,并构造监控统计量检测过程故障.在Tennessee Eastman过程上的故障检测结果表明,相比于传统的基于动态核主元分析的故障检测方法,该方法更加灵敏地检测到故障的发生,提高故障检测率.     

KPCA-KPLS方法在pH中和过程建模中的应用

针对化工过程中的具有严重非线性、不确定性、时变性的复杂pH中和过程系统建模问题,提出一种基于核主元分析(KPCA)与核偏最小二乘(KPLS)相结合的建模方法.在高维特征空间内,该方法通过KPCA有效地提取输入数据的非线性主元,利用KPLS方法将输入变量投影在潜在变量上,再用输入与输出变量之间的协方差信息提取潜在特征建立pH中和过程模型.为验证其有效性,将KPCA-KPLS方法应用到弱酸强碱中和过程、强酸强碱中和过程实例中,并与核偏最小二乘、核主元分析_支持向量机(KPCA-SVM)、核极限学习机(KELM)、极限学习机(ELM)、最小二乘支持向量机(LSSVM)、SVM等方法进行比较.实验结果表明:KPCA-KPLS方法具有很高的动态建模精度.     

基于免疫核主元分析的故障诊断方法

针对核主元分析(KPCA)中的复杂运算和故障分离问题,提出一种基于免疫核主元分析(immune-KPCA,IKPCA)的故障诊断方法.该方法使用小波变换技术对数据进行预处理,然后利用基于克隆选择原理的免疫算法对建模数据进行压缩,提取特征样本建立核矩阵以降低运算复杂程度.在IKPCA监控统计量检测到故障后,基于灵敏度分析思想构造贡献图分离故障变量.在连续搅拌反应釜(CSTR)仿真过程上的应用结果表明,本文提出的方法能够显著地降低核矩阵的计算量,比传统的PCA、KPCA方法更有效地检测过程故障,而且能够正确地识别故障变量.     

区域经济社会发展综合评价与预测

针对主成分分析(PCA)在多指标综合评价中非线性分析上的不足,提出了综合评价的核主成分分析(KPCA)方法.利用核函数将原空间映射到高维特征空间,在高维空间进行线性主成分分析;通过对核参数的适当选取,可使得最大特征值的贡献率达到或接近85%,避免了多个主成分的不同组合而导致评价结果不一致.在此基础上,利用最小二乘法建立核主成分回归方程--KPCR,并将其应用于区域经济社会发展综合评价与预测.     

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.     

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     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

正~~