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为了解决传统地图等高线、天气图等值线手工分析的缺点,而以计算机自动分析作替代。通过考察插值、拟合几种数学方法,提出如何应用三次B样条函数,处理格点数据,寻找等值控制点,进行曲线拟合,这一方法具有客观化程度高、分析速度快且线条光滑等特点。 相似文献
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运用非均匀有理B样条方法描述赛道内外边界以及赛车行驶线,并运用序列二次规划算法对赛车行驶线曲率进行优化.该方法能帮助赛道工程师在比赛前分析赛道特性. 相似文献
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LI Jun HAO Peng-wei 《浙江大学学报(A卷英文版)》2006,7(7):1168-1177
INTRODUCTION Homogeneous matrices are matrices used to represent geometric transformations for homogene- ous coordinates. Because they provide uniform rep- resentation for various transformations, they are widely used in the computer graphics community. As a homogeneous matrix corresponds to a geometric transformation, a curve on the set of homogeneous matrices can be taken as a piece of motion. Thus interpolation between those matrices is of high in- terest in many applications such as c… 相似文献
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主要针对基数B-样条函数及其基本性质，研究一类m阶基数B-样条小波插值的误差估计，获得了关于一类m阶基数B-样条小波插值的误差表示以及该类插值误差关于步长h的若干结果，重点是计算、基数B-样条小波逼近和误差处理，特别，这里所说的基数B-样条函数是指具有等距单重节点的多项式样条函数． 相似文献
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在CNC编程中用圆弧样条函数拟合列表曲线的数学方法,将双圆弧相切法应用于实际,使加工零件轮廓光滑连续,通过对大跨度型值点的加密,使逼近误差最小,减少尖角过渡,避免了爬行． 相似文献
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Mirror extending and circular spline function for empirical mode decomposition method 总被引：4，自引：0，他引：4
The Mirror Extending (ME) approach is proposed in this paper for solving the end extending issue in the Empirical Mode Decomposition
(EMD) method. By this approach, the data extended into a closed circuit without end. The derivatives on ends are not necessary
any more for Spline fingth. The approach eliminates the possible problems in reliability and uniqueness in the original extending
approach of the EMD method. In the ME approach only one extending is necessary before the data analysis. A tipient criterion
is proposed here for checking the extending approach. ME approach has been proved to satisy the theoretical criterion automatically
and permanently. This approach makes the EMD method reliable and casy to follow.
Project supported by NSFC (49634140, 49876008). Contribution No. 2001B001 from the Key Lab of Ocean Dynamic Processes and
Satellite Oceanography, SOA. 相似文献
8.
主流形和非线性维数化简的切向空间校正 总被引：8，自引：0，他引：8
We present a new algorithm for manifold learning and nonlinear dimensionality reduction. Based on a set of unorganized da-ta points sampled with noise from a parameterized manifold, the local geometry of the manifold is learned by constructing an approxi-mation for the tangent space at each point, and those tangent spaces are then aligned to give the global coordinates of the data pointswith respect to the underlying manifold. We also present an error analysis of our algorithm showing that reconstruction errors can bequite small in some cases. We illustrate our algorithm using curves and surfaces both in 2D/3D Euclidean spaces and higher dimension-al Euclidean spaces. We also address several theoretical and algorithmic issues for further research and improvements. 相似文献
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INTRODUCTION Offset curves/surfaces, also called parallel curves/surfaces, are defined as the locus of the points which are at constant distance along the normal from the generator curves/surfaces. As for a planar gen- erator curve Γ:C(t)=(x(t),y(t)), the parametric speed and its norm σ(t) are defined respectively as (Farouki, 1992) C ′( t ) =( x ′( t ), y ′(t )),σ (t ) = x ′ 2 (t ) y ′2(t ). (1) Subsequently the offset curve of the generator curve, which is at constant distanc… 相似文献
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样条曲面是CAD、CAM中常用的曲面,从三维空间坐标变换、双三次B样条曲面的消隐及显示等两个方面讨论了双三次B样条曲面的一种生成方法. 相似文献
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以上海证券交易所的上市国债数据所隐含的利率期限结构作为分析对象,通过选取三次多项式样条函数来构造我国的零息票收益率曲线,并对其进行分析评价· 相似文献
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三次样条函数的基样条法和三弯矩法之异同比较 总被引：1，自引：0，他引：1
为解决某些实际问题,需要引入逼近函数,常用的是样条函数。本文以三次样条函数为例,研究基样条法和三弯矩法的逼近程度,分析它们的优劣及二者的异同,以便在许多实际问题中更广泛地应用最佳逼近. 相似文献
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复杂曲面笔式加工的直接插补算法 总被引：2，自引：0，他引：2
针对复杂曲面笔式加工时位于曲面上的空间曲线型刀具轨迹,给出一种直接插补算法.即对以投影方式形成的位于曲面上的空间曲线形式的刀轨,根据导动曲线和刀触点轨迹线之间的几何运动关系,通过泰勒展开近似得到刀触点轨迹线上插补点所对应的导动线的参数,再反求间接得到刀触点坐标,从而生成控制机床运动的指令.该方法的实现扩充了CNC系统的轨迹控制功能,提高了复杂曲面的加工效率.仿真结果表明算法可行而且有效.该算法也可以应用到整体曲面加工中. 相似文献
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The problem of parametric speed approximation of a rational curve is raised in this paper. Offset curves are widely used in
various applications. As for the reason that in most cases the offset curves do not preserve the same polynomial or rational
polynomial representations, it arouses difficulty in applications. Thus approximation methods have been introduced to solve
this problem. In this paper, it has been pointed out that the crux of offset curve approximation lies in the approximation
of parametric speed. Based on the Jacobi polynomial approximation theory with endpoints interpolation, an algebraic rational
approximation algorithm of offset curve, which preserves the direction of normal, is presented.
Project supported by the National Basic Research Program (973) of China (No. 2002CB312101) and the National Natural Science
Foundation of China (Nos. 60373033 and 60333010) 相似文献
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彭卓华 《赣南师范学院学报》2008,29(3):15-17
提出一种迭代法求最小二乘问题min‖AXB-C‖的对称解.通过这种方法,给定初始对称矩阵X1,在没有舍入误差的情况下,经过有限步迭代,找到它的一个对称解.并且,通过选择一种特殊的初始对称矩阵,得到它的最小范数对称解X^＊.另外,给定矩阵X0,通过求解最小二乘问题min‖AXB-C‖（其中C=C-AX0B）,得到它的最佳逼近对称解. 相似文献
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第二类Fredholm积分方程的快速数值解法 总被引：1，自引：0，他引：1
吴静 《广东轻工职业技术学院学报》2004,3(1):1-5
对于具有弱奇性核函数的第二类Fredholm积分方程，将核函数所定义的区域分成大小不同的正方形子区域，利用分层插值多项式逼近核函数，由此得到近似矩阵B实现了积分方程的快速数值解法。在最后，对如何提高方案的数值稳定性作简要讨论并给出要讨论并给出数值结果。 相似文献
18.
The transfer matrix of wrist force sensor is important for decoupling theoutput signals and enhancing the precision of wrist force sensor.This paper solves thetransfer matrix from the realization of optimal approximation of polynomial.First,thegeneral transfer matrix algorithm in the sense of L~2 and two kinds of modified algorithmare proposed.Then,starting from uniform approximation,the optimal transfer matrixalgorithm is offered and solved by the use of linear programming.The results of experi-ment and computation prove that these algorithms are effective. 相似文献
19.
We present a new algorithm for manifold learning and nonlinear dimensionality reduction. Based on a set of unorganized data
points sampled with noise from a parameterized manifold, the local geometry of the manifold is learned by constructing an
approximation for the tangent space at each point, and those tangent spaces are then aligned to give the global coordinates
of the data points with respect to the underlying manifold. We also present an error analysis of our algorithm showing that
reconstruction errors can be quite small in some cases. We illustrate our algorithm using curves and surfaces both in 2D/3D
Euclidean spaces and higher dimensional Euclidean spaces. We also address several theoretical and algorithmic issues for further
research and improvements.
Project supported in part by the Special Funds for Major State Basic Research Projects (Grant No. G19990328) and Foundation
for University Key Teacher by the Ministry of Education(Grant No.CCR-9901986) 相似文献
20.
INTRODUCTIONTheOSSI(OffsetSurface/SurfaceIntersection)problemisasub-problemofgeneralSSI.AlthoughtheOSSIproblemcanberesolvedbyapplyinggeneralSSIalgorithm,itiscomputationallyexpensiveandexhaustive.Inrecentdecades,effortshavebeenfocusedoncomputingSSIexactly,efficiently,androbustlyinageneralsetting(Abdel-MalekandYeh,1997;Changetal.,1994;BurkeandSabharwal,1996;Mullenheim,1991).Thesetechniquescanbeclassifiedmainlyintofivecategories:algebraic,latticeevaluation,marching(tracing)method,… 相似文献