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一种基于端点非插值性的NURBS曲面重构方法 被引量:2
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作者 张国军 幸研 《东南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2016年第6期1161-1164,共4页
为了解决多面片拼接曲面、多修饰特征曲面连续性差且难以延展的问题,提出了基于端点非插值性的NURBS曲面重构方法.首先根据位置和曲率的不同,将原始曲面离散为点云数据,根据离散点计算各个采样路径上的节点矢量;然后计算出曲面重构所需... 为了解决多面片拼接曲面、多修饰特征曲面连续性差且难以延展的问题,提出了基于端点非插值性的NURBS曲面重构方法.首先根据位置和曲率的不同,将原始曲面离散为点云数据,根据离散点计算各个采样路径上的节点矢量;然后计算出曲面重构所需的端点非插值性的共同节点矢量及相应的控制点,并将共同节点矢量转化成标准的端点插值节点矢量,根据最新的端点插值节点矢量在无数据点区间插入新的型值点;最后将所有数据点重新拟合成单一曲面.重构结果表明,通过使用该方法重构所需的计算量降低,重构出的曲面精度较高.在曲率变化剧烈处,既保证了与原始曲面的贴合率,又保证了截面线的曲率连续性.该方法将原始曲面重构为单一曲面,提高了曲面重构精度,有效地解决了造型中易出现的曲面退化、曲面畸变等问题. 展开更多
关键词 均匀有理B样条 曲面离散 曲面重构 端点非插值性
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等几何分析中Dirichlet边界条件的配点施加方法 被引量:6
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作者 陈涛 莫蓉 万能 《机械工程学报》 EI CAS CSCD 北大核心 2012年第5期157-164,共8页
相对于传统有限元,等几何分析使用NURBS基函数统一表示几何和分析模型,它能消除传统有限元的网格离散误差,容易构造高阶协调单元。但是由于NURBS基函数缺乏插值性,控制顶点也不一定位于几何边界上,使得难以直接施加Dirichlet边界条件。... 相对于传统有限元,等几何分析使用NURBS基函数统一表示几何和分析模型,它能消除传统有限元的网格离散误差,容易构造高阶协调单元。但是由于NURBS基函数缺乏插值性,控制顶点也不一定位于几何边界上,使得难以直接施加Dirichlet边界条件。针对这一问题,提出一种基于样条拟合的Dirichlet边界条件施加方法,通过引入一组边界配点来拟合边界条件。注意到不合适的配点策略会使得边界插值方程组奇异或者条件数过大,详细讨论配点选取的基本准则,提出两种鲁棒的配点方案:Greville横标和Chebyshev插值点法。并且将配点方法扩展到最小二乘形式,设计一种快速的场变量消去算法。通过实例验证上述方法的可行性和有效性。试验结果表明,各种配点策略的收敛率基本保持在一个量级,因此配点法的关键是选择稳定的配点方案。 展开更多
关键词 等几何分析 非插值性 Dirichlet条件 边界配点法 Greville横标 Chebyshev插值
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CALCULATION OF NONLINEAR MAGNETIC FIELDS IN CYLINDRICALLY SYMMETRIC SYSTEM 被引量:3
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作者 Wu Xunlei Chen Xinqiao Ding Yaogen (Institute of Electronics, Chinese Academy of Sciences, Beijing 100080) 《Journal of Electronics(China)》 2003年第1期33-37,共5页
For the calculation of non-linear magnetic fields, a simple program can be as effective as a large commercialized software package. If relaxation methods are used, they must include successive over-relaxation and unde... For the calculation of non-linear magnetic fields, a simple program can be as effective as a large commercialized software package. If relaxation methods are used, they must include successive over-relaxation and under-relaxation and much attention must be paid to the relaxation factor and the interpolation. In this paper some skills are proposed on the setting of an interpolation switch and the choosing of saturation point so as to assure satisfied convergence properties. The numerical results by using these methods conform well to the tests. 展开更多
关键词 SATURATION CONVERGENCE INTERPOLATION
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A NEW ALGORITHM OF THE NONLINEAR ADAPTIVE INTERPOLATION 被引量:1
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作者 Shi Lingfeng Guo Baolong 《Journal of Electronics(China)》 2006年第5期708-712,共5页
The paper presents a new algorithm of NonLinearly Adaptive Interpolation (NLAI). NLAI is based on both the gradients and the curvature of the signals with the predicted subsection. It is characterized by adap- tive no... The paper presents a new algorithm of NonLinearly Adaptive Interpolation (NLAI). NLAI is based on both the gradients and the curvature of the signals with the predicted subsection. It is characterized by adap- tive nonlinear interpolation method with extracting the characteristics of signals. Experimental research testi- fies the validity of the algorithm using the echoes of the Ground Penetrating Radar (GPR). A comparison of this algorithm with other traditional algorithms demonstrates that it is feasible. 展开更多
关键词 NONLINEARITY Adaptive interpolation Ground Penetrating Radar (GPR)
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Anisotropic Interpolation Error Estimates of a Nonconforming Element
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作者 汪远征 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第2期232-235,共4页
The main aim of this paper is to study the local anisotropic interpolation error estimates. We show that the interpolation of a nonconforming element satisfy the anisotropic property for both the second and fourth ord... The main aim of this paper is to study the local anisotropic interpolation error estimates. We show that the interpolation of a nonconforming element satisfy the anisotropic property for both the second and fourth order problems. 展开更多
关键词 Adini's element anisotropic interpolation error estimates
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Multivariate Vector Valued Salzer's Theorem 被引量:3
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作者 陈之兵 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2003年第2期233-236,共4页
In this paper, the important Salzer's theorem for rational interpolation is generalized to the multivariate vector valued case.
关键词 MULTIVARIABLE rational interpolation Salzer's theorem.
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A Note on General Frames for Bivariate Interpolation 被引量:1
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作者 唐烁 邹乐 《Journal of Mathematical Research and Exposition》 CSCD 2009年第4期700-706,共7页
Newton interpolation and Thiele-type continued fractions interpolation may be the favoured linear interpolation and nonlinear interpolation,but these two interpolations could not solve all the interpolant problems.In ... Newton interpolation and Thiele-type continued fractions interpolation may be the favoured linear interpolation and nonlinear interpolation,but these two interpolations could not solve all the interpolant problems.In this paper,several general frames are established by introducing multiple parameters and they are extensions and improvements of those for the general frames studied by Tan and Fang.Numerical examples are given to show the effectiveness of the results in this paper. 展开更多
关键词 continued fractions blending rational interpolant unattainable point.
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Nonlinearity for a parallel kinematic machine tool and its application to interpolation accuracy analysis 被引量:1
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作者 汪劲松 王忠华 +1 位作者 黄田 D.J.Whitehouse 《Science China(Technological Sciences)》 SCIE EI CAS 2002年第1期97-105,共9页
This paper is concerned with the kinematic nonlinearity measure of parallel kinematic machine tool (PKM), which depends upon differential geometry curvalure. The nonlinearity can be described by the curve of the solut... This paper is concerned with the kinematic nonlinearity measure of parallel kinematic machine tool (PKM), which depends upon differential geometry curvalure. The nonlinearity can be described by the curve of the solution locus and the equal interval input of joints mapping into inequable interval output of the end-effectors. Such curing and inequation can be measured by BW curvature. So the curvature can measure the nonlinearity of PKM indirectly. Then the distribution of BW curvature in the local area and the whole workspace are also discussed. An example of application to the interpolation accuracy analysis of PKM is given to illustrate the effectiveness of this approach. 展开更多
关键词 parallel kinematic machine tool nonlinearity measure CURVATURE INTERPOLATION accuracy analysis
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On Models of Nonlinear Evolution Paths in Adiabatic Quantum Algorithms
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作者 孙杰 路松峰 Samuel L.Braunstein 《Communications in Theoretical Physics》 SCIE CAS CSCD 2013年第1期22-26,共5页
In this paper,we study two different nonlinear interpolating paths in adiabatic evolution algorithms for solving a particular class of quantum search problems where both the initial and final Hamiltonian are one-dimen... In this paper,we study two different nonlinear interpolating paths in adiabatic evolution algorithms for solving a particular class of quantum search problems where both the initial and final Hamiltonian are one-dimensional projector Hamiltonians on the corresponding ground state.If the overlap between the initial state and final state of the quantum system is not equal to zero,both of these models can provide a constant time speedup over the usual adiabatic algorithms by increasing some another corresponding "complexity".But when the initial state has a zero overlap with the solution state in the problem,the second model leads to an infinite time complexity of the algorithm for whatever interpolating functions being applied while the first one can still provide a constant running time.However,inspired by a related reference,a variant of the first model can be constructed which also fails for the problem when the overlap is exactly equal to zero if we want to make up the "intrinsic" fault of the second model - an increase in energy.Two concrete theorems are given to serve as explanations why neither of these two models can improve the usual adiabatic evolution algorithms for the phenomenon above.These just tell us what should be noted when using certain nonlinear evolution paths in adiabatic quantum algorithms for some special kind of problems. 展开更多
关键词 adiabatic evolution nonlinear evolution paths quantum computing
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