Comparison of numerical and analytical solutions for fly casting dynamics

This paper presents an approximate analytical model of the dynamics of a tapered fly line during a standard overhead cast. During casting, the line forms a nonlinear propagating wave that is frequently referred to as a ‘loop’ by fly casters. The geometry of the loop is described by three distinct parts: a straight bottom segment (attached to a stationary fly rod), a semi-circular segment that is propagating (i.e. the loop), and a straight top segment that is also propagating, (i.e. the traveling line). A fly (particle) is attached at the end of the traveling line. A work-energy balance yields the velocity of the fly as a function of the length of the traveling line. For a uniform fly line (level line), a closed-form solution is found, while for a tapered fly line, the solution is obtained by quadrature. A critical loop diameter arises in the analysis, and it determines whether the final velocity of the fly is greater or lesser than the initial velocity of the traveling line. The analytical solutions are critically compared against numerical solutions of a general model for fly line dynamics that relaxes many of the assumptions employed in the analytical model. The agreement between the two solutions remains close during the loop propagation phase, provided a significant amount of fly line remains in the traveling line. However, as the traveling line vanishes and the loop ‘turns over’, the two solutions diverge abruptly due to the many simplifying assumptions employed in the analytical model.     

修正的q-Stancu—Beta算子的加权统计逼近性质

基于q-整数的定义,引入了一类修正的q-Stancu—Beta算子,由算子的各阶矩量、中心矩量及加权光滑模结合统计逼近的概念,得到了算子的加权统计收敛定理,并研究了算子的局部逼近性质,得到了算子的局部逼近定理．     

面波法与单孔检层法波速测试的工程应用

简述了面波法与单孔法等波速测试方法的工作原理、现场施测技术以及数据处理和资料分析过程.以工程实例说明了波速测试技术在岩土工程勘察设计中的应用及其效果.最后就勘探工作的总体安排及其原位测试方法的选择进行了探讨.     

严格凸Banach空间中最佳逼近元的存在与唯一性

在严格凸Ｂａｎａｃｈ空间中,引入保持严格凸性的范数,得到了严格凸Ｂａｎａｃｈ空间积空间的严格凸性,证明了单空间和积空间中关于无穷维紧凸子集最佳逼近元的存在与唯一性定理,改进和推广了某些已有结果。     

L~ψ空间中的Jackson定理

研究了Lψ空间中的函数用多项式逼近的问题 ,证明了Jackson定理 .     

关于Cauchy中值定理中值的渐近性与收敛速度

对Ｃａｕｃｈｙ中值定理的中值的渐近性给出了一些结果,并建立了收敛速度。     

q-Durrmeyer-Stancu算子的统计逼近性质

本文引进一类q-Durrmeyer-Stancu算子,并研究该算子列的一些统计逼近性质。得到算子列的统计逼近定理,同时借助连续模和Lipschitz函数类给出算子列统计收敛速度的估计。     

美式有分红看涨篮子期权解析近似定价模型

针对有分红美式篮子看涨期权,使用格点法与蒙特卡罗模拟法定价时,会产生＂维数灾难＂.对此,将期权的收益项进行适当改写,然后利用几何平均与算术平均之间的关系,将标的资产组合从算术平均转化为几何平均;然后在单标的资产美式期权解析近似定价模型的基础上,提出了一种解析近似方法为美式分红篮子看涨期权进行定价（Analytical Approximation Method,简称AAM）.此方法解决了＂维数灾难＂问题.最后,通过数值结果验证了该方法的有效性。     

一类特殊半鞅驱动的随机微分方程解的存在唯一性

研究了随机微分方程dXt=F(X)tdZt解的存在唯一性,其中F为非Lipschitz系数,Z属于一类特殊半鞅.     

基于形状特征小波分解的目标识别方法

形状特征是目标识别的重要参数,而小波变换的低频部分代表物体的总体形状特征.首先选取SYM小波,利用小波变换的低频系数重构图像提取物体总体形状,进而利用特征不变矩距离进行目标识别。将该方法应用在实测车标图像的识别中,结果表明该方法识别效果较好。