Results 11 to 20 of about 355 (68)
A boundary-type meshless method for the Robin inverse problem(一种求解Robin反问题的边界型无网格方法)
Zhejiang Daxue xuebao. Lixue ban, 2013 给出一种求解非齐次稳态热传导方程Robin反问题的边界型无网格方法.该方法首先利用Newton法则将Robin反问题转化为Cauchy问题，然后用边界粒子法处理非齐次项以避免区域内部的离散节点，并结合基本解方法分别求得近似特解以及相应齐次问题的近似解.鉴于所考虑问题的不适定性，引入截断奇异值分解和L-曲线准则来求解离散后得到的高度病态的线性方程组.最后给出数值例子说明该方法的稳定性和有效性.
DONGChao-feng(董超峰)
doaj +1 more source
Low pilot overhead parametric channel estimation scheme for RIS-assisted mmWave MIMO systems [PDF]
To address the timely acquisition of channel state information in reconfigurable intelligent surface (RIS)-assisted millimetre wave (mmWave) multiple-input multiple-output (MIMO) systems, a channel estimation scheme based on tensor decomposition was ...
GUO Xin +3 more
core +1 more source
Accelerated random noise suppression of seismic data using compressed singular-value decomposition [PDF]
Random noise is one of the common background noises in seismic data, and its attenuation will directly affect the signal-to-noise ratio of seismic data, which is of great significance to improve the quality of seismic data.
LIN Peng +4 more
core +1 more source
Fast Radar Forward-looking Super-resolution Imaging for Abnormal Echo Data [PDF]
Forward-looking imaging of airborne scanning radar is widely used in situation awareness, autonomous navigation and terrain following. When the radar is influenced by unintentional temporally sporadic electromagnetic interference or abnormal equipment ...
Dong WANG +6 more
core +1 more source
Dianci bileiqi, 2020 超特高压直流输电系统单极大地运行时,直流电流经过接地极在地中形成恒定电场,对周围电力设施、环境产生一定的影响,且极址附近大范围复杂土壤结构是影响地中电流散流的主要因素。因此本文建立考虑大范围复杂土壤结构的直流接地极有限元数值计算模型;其中针对数千米的求解区域和接地极0. 04 m的截面半径之间存在105数量级差异导致的剖分奇异问题,引入"薄壳"理论;根据地下暗河及断裂层等实际情况构建含有水平层状、垂直层状的土壤结构,分析接地极在异阻层状土壤处于不同位置及环境土壤电阻率不同时的散流性能。得出结论 ...
李景丽, 栗超超, 冯鹏
doaj
A Modified Numerical Algorithm for Fredholm Integral Equations and Its Application [PDF]
, 2007 粘弹性是熔融聚合物的一个重要特性，通常可以利用离散线性松弛谱来进行表征。松弛谱一般由动态模量的实验数据计算得到。然而松弛谱的计算是一个不适定问题，通常随着离散松弛谱个数的增加，问题的病态性也加重。常用的线性回归方法的缺点是松弛时间需事先给定，且通常不一定满足不适定问题可解的离散Picard条件。为了避免这个问题，一些算法（如NLREG和GENEREG）用一个非线性积分核来代替原来的线性积分核，而非线性回归方法如IRIS把松弛时间也认为是变量，这些方法在处理完整实验数据情况下都能得到很好的结果 ...
李俊杰
core
Novel approach to SVD-based image filtering improvement [PDF]
, 2010 提出一种提高SVd滤波性能的新方法。基于奇异值分解滤波可以有效地分析水平(垂直)方向的图像特性。根据图像的局部方向,自适应地调整待滤波区域的形状,使重采样后局部区域中的边缘垂直或水平,再对局部区域进行奇异值分解滤波;所得的结果加权平均,得到信号估计值。将这一算法应用于图像去噪,实验结果表明,新方法可以有效地提高SVd的滤波性能。A novel approach to improve the filtering efficiency of a noisy image is proposed.Image ...
李翠华, 杜晓凤, 杨敦旭
core
Guangtongxin yanjiu, 2010 针对小波阀值法对噪声非均匀分布振动信号消噪差的缺点,提出了奇异值分解（SVD）结合小波阀值消噪的算法。采用截断法构造出包含信号信息及非均匀噪声的相关矩阵并进行SVD,得到一系列正交子空间,将非均匀噪声相对均匀地分解到子空间中。选取奇异值最大的子空间分量重构信号并对此信号进行了小波阀值消噪。结果表明,该方法适用于非均匀噪声干扰下的振动信号提取,与直接小波消噪相比,提取出的信号失真更小,信号有效成份更完整。
李靖, 毕卫红, 刘微
doaj
[Practical guideline on the prevention and management of diabetic foot in China (Ⅰ)]. [PDF]
Zhonghua Shao Shang Yu Chuang Mian Xiu Fu Za ZhiChinese Burn Association +2 more
europepmc +1 more source
[Clinical observation of posttransplant lymphoproliferative disorder in a single center]. [PDF]
Zhonghua Xue Ye Xue Za ZhiQiao ZQ +12 more
europepmc +1 more source