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A unified intrinsic functional expansion theory for solitary waves 被引量:3
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作者 Theodore Yaotsu Wu John Kao Jin E.Zhang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2005年第1期1-15,共15页
A new theory is developed here for evaluating solitary waves on water, with results of high accuracy uniformly valid for waves of all heights, from the highest wave with a corner crest of 120<SUP></SUP> do... A new theory is developed here for evaluating solitary waves on water, with results of high accuracy uniformly valid for waves of all heights, from the highest wave with a corner crest of 120<SUP></SUP> down to very low ones of diminishing height. Solutions are sought for the Euler model by employing a unified expansion of the logarithmic hodograph in terms of a set of intrinsic component functions analytically determined to represent all the intrinsic properties of the wave entity from the wave crest to its outskirts. The unknown coefficients in the expansion are determined by minimization of the mean-square error of the solution, with the minimization optimized so as to take as few terms as needed to attain results as high in accuracy as attainable. In this regard, Stokess formula, F<SUP>2</SUP>= tan , relating the wave speed (the Froude number F) and the logarithmic decrement of its wave field in the outskirt, is generalized to establish a new criterion requiring (for minimizing solution error) the functional expansion to contain a finite power series in M terms of Stokess basic term (singular in ), such that 2M is just somewhat beyond unity, i.e. 2M1. This fundamental criterion is fully validated by solutions for waves of various amplitude-to-water depth ratio =a/h, especially about 0.01, at which M=10 by the criterion. In this pursuit, the class of dwarf solitary waves, defined for waves with 0.01, is discovered as a group of problems more challenging than even the highest wave. For the highest wave, a new solution is determined here to give the maximum height <SUB>hst</SUB>=0.8331990, and speed F<SUB>hst</SUB>=1.290890, accurate to the last significant figure, which seems to be a new record. 展开更多
关键词 Solitary waves on water Unified intrinsic functional expansion theory exact solutions High-accuracy computation of waves of arbitrary height Mass and energy transfer
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用于快速形状匹配的精确型高度函数特征描述 被引量:5
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作者 孙国栋 张杨 +2 位作者 李萍 梅术正 赵大兴 《光学精密工程》 EI CAS CSCD 北大核心 2017年第1期224-235,共12页
在形状匹配过程中为了提升高度函数描述子的检索精度和对边界噪声与局部变形的鲁棒性,本文提出了一种精确型高度函数特征描述算法。首先提取目标形状外轮廓,构造轮廓采样点的精确型高度函数描述子并进行特征降维,接着利用优化后的并行... 在形状匹配过程中为了提升高度函数描述子的检索精度和对边界噪声与局部变形的鲁棒性,本文提出了一种精确型高度函数特征描述算法。首先提取目标形状外轮廓,构造轮廓采样点的精确型高度函数描述子并进行特征降维,接着利用优化后的并行动态规划进行形状匹配,最后引入形状复杂度分析提升匹配效果。基于点的几何特征显著性,提出形状精度理论,进一步分析局部形变与边缘噪声对形状特征描述的影响。在MPEG-7数据库、Swedish Leaf数据库、Tools数据库和ETH-80大型3D数据库上进行匹配实验以及在Kimia99数据库上进行抗噪实验,实验结果表明:本文提出的算法效率高,匹配时间仅为高度函数描述子的12.5%,在MPEG-7和ETH-80上的检索率最高分别为90.38%和90.07%;在Swedish Leaf和Tools上,检索精度最高分别为95.07%和94.86%,检索性能和鲁棒性均优于高度函数和其他重要算法;在添加噪声的Kimia 99上,该算法的抗噪性能优于高度函数描述子,即使在噪声水平为2.0的情况下,依旧能保持91.92%的检索率。本文提出的算法检索精度高,效率高,鲁棒性好,抗噪性强,具有较好的可扩展性,能有效地应用于形状检索领域。 展开更多
关键词 形状匹配 精确型高度函数 形状精度 并行动态规划
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