基于粒子群算法的盲源分离算法

简要地介绍了粒子群算法(PSO)及其改进算法和盲源分离算法(BSS),改进的粒子群算法具有并行性、易实现等优点。将改进的粒子群算法与盲源分离算法相结合,提出了基于粒子群算法的盲源分离算法。该算法以混合信号的峰度为目标函数,采用独立分量分析的方法,用改进的粒子群算法代替常规的最陡梯度下降法,对瞬时混合的信号进行盲分离,解决了梯度算法收敛速度慢的问题。实验仿真表明:该算法具有收敛速度快、分离效果好等特点。     

核独立分量分析在盲源信号分离中的应用研究

提出利用核独立分量分析来分离混合语音信号的盲信号处理方法.介绍了基于核空间ICA的原理和基本算法,然后利用核独立分量分析算法和固定点快速分离算法分离了混合语音信号.试验结果表明:利用基于核独立分量分析的方法可以得到较为理想的分离效果.     

小波分解单通道盲分离干扰抑制方法

在单通道通信系统抗干扰问题中,由于先验信息不足,不能采用常规的盲分离方法抑制干扰?针对此问题,提出一种小波分解结合独立分量分析(independent component analysis,ICA)的单通道盲分离抗干扰方法?该方法利用小波分解,将单路混合信号分解为一系列的小波分量,通过计算各层小波分量的能量,选择最优小波分量作为ICA的输入信号,采用ICA方法实现信号的分离和重构?该方法选择最优小波分量进行盲分离,有效减少分离算法的计算量,同时降低噪声对系统性能的影响?仿真结果表明,所提方法可以有效地分离混合信号,提高单通道通信系统的抗干扰能力和系统处理速度?     

基于粒子群算法的盲源信号分离

当源信号个数大于2,联合对角化（JADE）算法在盲源信号分离时效果不理想.提出了一种基于粒子群算法（PSO）的盲源信号分离（BSS）算法.该算法利用PSO算法代替JADE算法中的联合对角化操作,以混合信号的峭度为目标函数,采用独立分量分析的方法,对瞬时混合的信号进行了盲分离,理论分析和仿真结果表明了该算法的可行性和有效性.     

基于独立分量分析与二值掩膜的语音分离

针对欠定混合语音信号模型,提出一种基于独立分量分析和二值掩膜相结合的语音分离新算法.首先,由并列放置的两个全指向性麦克风采集混合声音信号,通过一阶差分麦克风阵列技术使得两路混合信号满足瞬时混合模型;然后,应用两输入两输出独立分量分析方法对两路信号进行分离并估计分离信号的二值掩膜,循环迭代进而提取目标语音信号;最后,合并同源语音信号,增强各独立声源.仿真结果表明:该方法不仅适用于瞬时混合模型,对卷积混合模型同样有效;在瞬时混合条件下信噪比增益平均达到12.41dB,在卷积混合条件下信噪比增益平均为5.28dB.试验结果表明:算法在半消音室环境下能准确分离来自不同方位的三个声源,提取的目标语音都具有较高的清晰度与可懂性.     

一种新的盲声源信号分离方法及其应用

从盲声源信号的独立性出发,提出了一种新的盲声源混合信号分离方法.该方法基于信号联合概率的分布统计,利用信号联合概率的方向导数熵最小获得最佳的旋转角度,最终实现盲信号分离.与快速独立分量分析方法及神经网络方法相比,该方法不需要迭代计算.采用新的盲声源信号分离方法对轴承试验台的混合声音信号进行识别,将电机和滚动轴承的声音分离出来,进而可以准确识别机械的故障.     

基于小波变换和FASTICA算法的有噪混合图像盲分离

简要介绍了独立分量分析的基本数学模型和算法,在此基础上,探讨了独立分量分析在有噪混合图像分离中的应用,提出了一种将小波阈值法去噪与独立分量分析相结合的多通道含噪盲信号分离算法,该算法在对混合含噪图像进行独立分量分析之前,使用小波阈值去噪去除含噪混合图像中的噪声.实验结果表明,该方法能有效地降低噪声信号的影响,较好地恢复了原始图像,解决了传统的独立分量分析方法无法实现加性噪声的多通道含噪盲信号分离的缺陷.     

单通道涡流无损检测信号盲源分离算法

针对脉冲涡流无损检测(pulsed eddy current testing, PECT)系统中获取单一检测信号存在的混叠问题,文章提出一种基于经验模态分解(empirical mode decomposition, EMD)和快速独立分量分析(fast independent component analysis, FastICA)的单通道盲源信号分离算法。该算法首先通过EMD对混合观测信号分解,然后利用奇异值分解(singular value decomposition, SVD)估计源信号数目,根据估计得到的源信号数目将观测信号和对应模态分量构成新的虚拟信号,最后利用FastICA算法分离得到源信号的估计。有限元仿真实验表明该算法能有效分离单通道混合检测信号,并且优于小波分解的单通道盲源分离算法。     

基于遗传算法的盲源分离算法

针对现有盲源分离算法的性能依赖于对比函数选择的现象,提出了一种基于遗传算法的盲源分离算法,该算法直接从信号的样本序列中估计出信号的概率分布,解决了信号间互信息的求解问题.通过遗传算法最小化信号的互信息,实现了对线性混叠信号的分离.对模拟信号的分离结果表明,该算法可以成功地分离混叠信号,同时与快速独立分量分析算法相比,该算法的性能对源信号的概率密度性质没有依赖,因而对亚高斯和超高斯信号的混合信号表现出更加优异的分离能力.     

基于独立分量分析的混合声音信号分离

论文简要介绍了有关独立分量分析（ICA）的基本理论和算法;探讨了独立分量分析在混合声音信号分离中的应用。针对ICA输出结果排序的不定性以及在长时间记录声音信号的过程,ICA混合模型系数存在时变性等问题,提出了一种结合小波变换和独立分量分析的解决方法;试验结果表明,该方法能有效地提高运算效率并获得较好的分离效果。     

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