改进的分数阶自适应PDE去噪算法

结合ROF模型和四阶PDE去噪模型提出一种改进的分数阶自适应PDE去噪算法.改进算法根据各个像素点的梯度信息自适应地选择分数阶PDE的阶数,根据尺度参数的特点,提出一种自适应的尺度参数迭代算法.数值实验表明,改进算法能够较好地提高峰值信噪比,保护边缘,有效抑制“阶梯效应”.     

一种改进的自适应PDE去噪算法

讨论了经典的偏微分方程去噪模型——TV模型和四阶PDE去噪模型的优点与不足,提出一种改进的综合去噪模型。通过自适应的系数选择,将TV模型和四阶PDE去噪模型进行加权组合.数值试验结果表明,改进算法不仅保留了传统算法的优点,而且能有效提高去噪效果.     

基于PDE算法的指静脉图像预处理

为了更好地去除手指静脉图片中的噪声, 提出一种基于偏微分方程算法（PDE）的去噪新模型. 该模型在P M模型的基础上, 采用新的扩散函数, 并结合四阶PDE模型对原模型结构进行变换. 用合成图像和真实指静脉图像分别对新模型进行实验验证, 结果表明, 相对于P M模型, 新模型使信噪比（SNR）值提高了约5 dB, 且能在去除噪声的同时很好地保持指静脉特征.     

基于MOS管PDE模型的RF电路瞬态包络仿真算法分析

提出了以谐波平衡技术为平台,基于RF电路中MOS晶体管PDE模型的混合域瞬态包络仿真算法,解决了将MOS晶体管的PDE模型与表征电路系统的ODE耦合在一起进行数值求解的问题,并以一个功放电路为例说明了这种仿真技术的有效性。     

基于纯各向异性扩散和四阶PDE的混合去噪方法研究

综合纯各向异性扩散模型和四阶PDE模型在图像去噪中的特点,提出一种新的去噪模型——基于纯各向异性扩散和四阶PDE的混合去噪模型.该模型克服了四阶PDE模型过多损失边缘信息和纯各向异性扩散模型在平滑区域产生阶梯效应的缺点,在有效去除噪声的同时,既抑制了阶梯效应,又很好地保持了图像的边缘和纹理细节信息.     

基于偏微分方程的非线性弱目标增强算法

为解决低对比度弱目标单帧检测率较低的问题,提出一种基于偏微分方程(PDE)的弱目标增强算法,对传统的P-M各向异性扩散模型进行改进,在扩散函数中引入锐化因子,通过选取适当的梯度门限和锐化强度参数,自适应地平滑背景和增强弱目标.该算法与中值滤波相结合,消除了传统模型在处理椒盐噪声方面的缺陷.仿真实验表明,该算法可有效克服传统滤波器的缺陷,在抑制干扰和噪声的同时增强目标.     

基于耦合PDE的图像处理

本文介绍了偏微分方程(PDE)在图像处理中的应用,并提出一耦合方程,给出具体数值算法,用实验验证了该方程模型在图像处理中的实际处理效果。     

一种基于PDE提高信噪比的图像处理算法

研究了PDE在数字图像处理方面的应用.从能量分析法切入,构造变分问题,从而得到原始模型;以去噪、提升边缘、保留原图信息为目标改进了原始模型.对于图像处理的难点问题———边缘的去噪去模糊,在文中得到较好的解决.结果表明:经过该方法处理后的图像在提升信噪比方面十分显著,由此建立的扩散模型不仅产生了一种新算法,而且为人们在该领域的后续研究提供了参考.     

基于结构张量扩散的改进PDE滤波算法

从扩散的角度分析了图像处理中传统热扩散和PM模型的不足,提出了一种各向异性的改进PDE滤波算法.该算法利用图像的结构张量信息和局部特征,自适应选取扩散系数,在图像平坦区域,具有各向同性扩散;而在图像边缘处,则只沿着切向扩散.实验结果表明,该算法具有良好的滤波性能,在滤波的同时可有效保护边缘细节,对灰度图像特别是医学图像,相对于传统方法,该算法可以获得更好的主观视觉效果和客观性能评价指标.     

图像去噪的ROF模型及仿真实验

基于PDE模型的图像去噪是一种非常有效的方法,本文给出了离散迭代格式,通过C++仿真实验验证了算法对抑制噪声的有效性,实验结果显示该算法能很好地保持边缘等细节特征,且峰值信噪比得到有效提高。     

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     

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