基于RBF网络的金融时间序列预测

RBF网络是一种新颖有效的前向型神经网络,它通过非线性基函数的线性组合实现从输入空间RN到输出空间RM的非线性转换,特别适合于非线性时间序列如股票市场等金融系统的预测.本文以中集集团的实际收盘价作为预测对象,提出基于RBF网络的个股价格预测模型,仿真实验表明,该模型对于个股价格的短期预测是可行有效的.     

基于改进GA的WRBF神经网络设计与应用

针对单独自动设计径向基函数(RBF)网络和小波网络过程中对样本要求过于严格,以及输出层线性求和运算可能造成样本类别交叠的问题,结合两种网络结构简单的优点,设计了一种新的四层前馈神经网络--小波径向基网络(Wavelet radial basis network,WRBF).该网络在结构上,第一隐层对输入样本进行小波映射,实现对输入空间的压缩;第二隐层对第一隐层输出进行第二次非线性映射;在网络的训练方法上,利用多阶染色体混合编码实现两隐层间的选择性连接,并对遗传算法(Genetic algorithm,GA)进行改进,利用改进的GA同时优化网络结构和参数.通过对多输入单输出系统和热能表系数模型进行实验,结果表明:改进的GA减小了早熟收敛的发生,所设计的网络具有较高的建模精度.     

神经网络在动力学系统建模中的理论研究

动力学系统可以看成是映输入空间到输出空间的一个算子,在特定时刻动力学系统的输出可以看成是其输入空间上的一个泛函,这样动力学系统建模就可以看作是表征系统映射关系的算子或泛函的逼近问题。研究了多层神经网络的非线性映射能力,给出了多层网络可一致逼近有限维空间Ｒｎ紧集上的连续函数、无穷维函数空间紧集上的连续泛函和连续算子的理论证明。得出的几个一般性结论为在动力学系统建模等领域应用神经网络准备了理论工具。     

基于遗传算法优化的RBF网络在自校正控制中的应用研究

针对RBF神经网络参数难以确定的情况,采用遗传算法对RBF神经网络的隐层中心值和宽度进行了优化,用递推最小二乘法训练隐层和输出层之间的权值。给出一种基于优化的RBF神经网络的自校正控制算法,利用神经网络的非线性函数映射能力,使其充当未知系统函数逼近器。仿真结果表明了所给算法的有效性。     

电容压力传感器的函数链接型神经网络建模方法

旨在开发一种计算简单的电容压力传感器的模型，以便经济、可靠地应用。分析表明，采用新型函数链接型神经网络建立的电容压力传感器模型，能够精确读出应用压力。它是一种能实现输入到输出的高度非线性映射并且运算高效的非线性网络，在建立传感器模型的类似性能上比多层感知器具有更高的运算优势。     

RBF神经网络主成分分析法在交通量预测中应用

文章基于径向基函数(RBF)神经网络应用于交通量预测时,如果输入空间严重自相关及网络维数较高时,RBF神经网络的预测精度会下降这一问题,提出了一种改进的RBF神经网络主成分分析法。用实例证明,该方法在模拟预测中与一般的RBF神经网络模型相比有较好的效果。     

利用RBF神经网络提高温度测量精度

本文介绍在压力测量时,为提高测量精度,利用径向基函数神经网络（RBF）和智能温度传感器DS1822进行温度补偿,改善其测量精度的新方法。RBF网络具有良好的非线性映射能力,自学习和泛化能力,采集样本数据训练构成具有双端输入、单端输出网络模型,采用改进的算法实现测量精度。     

基于RBF神经网络的快速伺服刀架迟滞特性建模

为了减小压电陶瓷固有的迟滞非线性特点对快速伺服刀架(FTS)控制精度的影响,提出了一种基于RBF神经网络的快速伺服刀架迟滞特性建模方法.利用拓展输入空间法建立了FTS迟滞系统的RBF神经网络模型,通过引入指数型迟滞算子,将FTS系统的输入与迟滞算子的输出一起作为RBF神经网络的输入向量,实现了FTS迟滞系统由多值映射到单值映射的转换,进而利用神经网络对其进行建模.为了更精确地跟踪快速伺服刀架的迟滞位移曲线,通过增加调整系数σ来对迟滞算子进行改进.实验表明,该迟滞模型可以很好地预测快速伺服刀架的迟滞位移曲线,模型的验证均方差MSE=5.163 3×10-6.     

多项式基函数神经网络模型

从函数逼近理论出发，用一组正交基函数作为三层前向神经网络各隐含单元的输出特性，以其加权和作为网络的非线性输出，构成一种单输入单输出正交基函数神经网络模型。建立了多输入的多项式基函数神经网络，并给出了非线性静态特性拟合，ＸＯＲ特性和动态特性拟合计算机仿真结果。     

基于RBF-BP复合神经网络的企业创新能力评价模型

为更加精准地测量企业创新能力,利用熵值法和相关性分析,从创新投入、创新产出、创新支撑3个维度建立企业创新能力评价指标体系,构建企业创新能力评价的RBF BP复合神经网络模型。该模型由1个输入层、1个RBF隐含层、1个BP隐含层以及1个输出层组成,其特点是将RBF隐含层的输出作为BP隐含层的输入。十折交叉验证与随机二次抽样2种方法检验表明,与单一RBF神经网络、单一BP神经网络相比,RBF BP复合神经网络模型的平均均方误差与平均绝对误差分别下降2821%、1519%和1251%、1255%,表明RBF BP复合神经网络模型具有最优的数据拟合能力,更适合于企业创新能力评价。     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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