基于DEM的有源淹没算法设计与实现——以种子蔓延法为例

 针对传统有源淹没的递归、迭代算法占用计算机资源较多,且当算法深度太深时易造成系统堆栈溢出,从而导致程序崩溃等缺点,以数字高程模型为基础,研究了给定水位条件下洪水有源淹没模型和算法,并在此基础上设计实现了种子蔓延算法。通过与原有的递归算法对比,发现该算法在一定程度上提高了计算效率和稳定性,最后在“南昌洪水淹没分析系统”中应用并得到验证。     

基于脉冲耦合神经网络的超声图像病理区域检测算法

超声图像的病理区域检测对辨别疾病的良恶性具有极其重要的价值.针对超声回声大、粒状斑点多的特点,提出了基于脉冲耦合神经网络的区域自动检测算法.首先脉冲耦合神经网络对图像进行点火处理,经过形态学闭运算、二值反相、区域标记等操作,自动提取出种子点;以种子点为种子像素对图像进行区域增长,提取出感兴趣的区域,经过伪彩色编码增强后,凸显病理区域,便于医学临床诊断观察与超声图像的进一步量化分析处理.     

洪水淹没范围数据与动力学模型的融合

为将遥感数据定量地应用于洪水动力过程的分析,拓展遥感数据的应用潜力,开展了洪水淹没范围数据与洪水动力学模型融合的方法研究.以糙率作为控制变量,构建了基于新形式代价函数的变分模型来融合洪水淹没范围数据和洪水动力学模型.采用溃堤洪水过程的合成观测数据,在敏感性分析基础上开展了淹没范围数据同化试验.结果表明,不同区块的糙率对洪水过程的影响是不同的,洪水漫滩范围对在滩地入流口近区主流向上的糙率最为敏感;运用研制的变分模型可以将洪水淹没范围的数据信息自动融入洪水动力学模型,识别糙率参数,更好地实现洪水过程的分析.     

基于Spark的并行ISOMAP算法

为了实现大数据环境下非线性高维数据的降维,提出了基于Spark的并行ISOMAP算法.在该方法中,为了快速求解大规模矩阵的特征值和特征向量,设计并实现了基于Spark的并行块Davidson方法;同时,针对大规模矩阵计算和传输困难的问题,提出了基于RDD分区的行块式矩阵乘法策略,该策略把每个分区中的矩阵行转换成块矩阵,行块式矩阵可不受map算子对RDD逐条计算的限制,并可以利用Spark中的线性代数库参与矩阵级别的运算.实验结果表明,行块式矩阵乘法策略有效提高了矩阵运算的效率,并行块Davidson方法能够快速求解大规模矩阵特征值和特征向量,有效提高了并行ISOMAP算法的性能,表明并行ISOMAP算法可以适应大数据环境下的降维处理.     

一种基于数据分块的海量地形快速漫游方法

大范围、海量地形数据的快速漫游是GIS、虚拟现实、游戏、仿真等领域的关键技术与难点之一。在目前地形数据简化算法的基础上,结合计算机硬件技术的发展,采用基于数据分块、部分数据常驻内存以及与视点相关的静态LOD模型实现了对任意格网大小海量地形数据的快速漫游。基于块节点的视景体裁剪、三角形条带组织以及边界裂缝消除、视觉光滑处理等手段的运用,提高了地形漫游的效率与可视化效果。     

一种基于Bresenham算法的圆内区域填充新算法

为了克服计算机图形学中的基于种子点的圆内区域填充的递归算法的不足,提出了一种基于改进的Bresenham圆生成算法的非递归的圆内区域填充新算法。实例证明,相对递归填充算法,新算法具有简单、快速、精确且占用内存空间小的优点。     

海量数据分析及处理算法实现

随着科学技术的发展,计算机的计算能力每年也都在飞快增长,需要处理的数据量更是呈指数级的增长。这样,对海量数据的分析处理是当今的重要话题之一。在实际应用中,因为笔者需要处理csv文本文件中的海量数据,数据量至少在25M以上,并要求处理时间能达到客户的需求,所以设计了一种快速处理海量数据的算法。该算法中包括对海量数据的提取...     

视频压缩感知中基于快速搜索的迭代多假设算法

针对观测域和像素域两阶段多假设预测重构方案在低采样率时重构效果不理想,且对于运动剧烈的序列预测精度不够、时间复杂度较高等问题,在两阶段多假设预测的基础上,提出了基于快速搜索的迭代多假设预测重构算法.该算法利用像素域分块的灵活性,基于重叠块在像素域迭代预测重构;针对运动较快的序列,采用十字形联合区域搜索方法以减小大范围搜索的算法复杂度;同时利用图像空间相关性进行帧间/帧内自适应假设块的模式选择与已有算法相比,文中重构算法进一步削弱了块效应,降低了大范围搜索的运算复杂度,提高了重构性能.     

基于阈值分割与数学形态学的高分辨率遥感影像道路信息提取

从高分辨率遥感影像中快速,有效的提取道路信息,一直是遥感学界研究的热点和难点问题。本文研究了一种基于阈值分割与数学形态学的高分辨率遥感影像道路提取算法,该算法不需人工给出道路种子点,方向等信息,在某种意义上提高了道路提取的自动化程度。提取过程是:首先利用阈值分割将遥感影像分割成包含道路信息的二值图像,然后利用数学形态学运算对二值图像进行处理,根据道路形态特征提取出道路区域。     

一种基于Rough集的海量数据属性约简方法

海量数据属性约简的研究是数据挖掘研究中的一个难点.已有的许多属性约简算法对于空间复杂度考虑得不够,导致了算法不能适应大数据集的约简处理.结合分治法,在给定属性序下,提出了基于分治策略的属性约简算法.利用该算法可以快速得到海量数据的属性约简结果.仿真实验结果说明了该算法的高效性.     

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.     

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     

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

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