基于国债的零息票收益率曲线

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·     

Mirror extending and circular spline function for empirical mode decomposition method

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.     

Relation among C-curve characterization diagrams

As three control points are fixed and the fourth control point varies, the planar cubic C-curve may take on a loop, a cusp, or zero to two inflection points, depending on the position of the moving point. The plane can, therefore, be partitioned into regions labelled according to the characterization of the curve when the fourth point is in each region. This partitioned plane is called a "characterization diagram". By moving one of the control points but fixing the rest, one can induce different characterization diagrams. In this paper, we investigate the relation among all different characterization diagrams of cubic C-curves based on the singularity conditions proposed by Yang and Wang (2004). We conclude that, no matter what the C-curve type is or which control point varies, the characterization diagrams can be obtained by cutting a common 3D characterization space with a corresponding plane.     

MIRROR EXTENDING AND CIRCULAR SPLINE FUNCTION FOR EMPIRICAL MODE DECOMPOSITION METHOD

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＥｍｐｉｒｉｃａｌＭｏｄｅＤｅｃｏｍｐｏｓｉｔｉｏｎ (ＥＭＤ)ｍｅｔｈｏｄａｎｄｉｔｓＨｉｌｂｅｒｔＳｐｅｃｔｒｕｍｔｅｃｈｎｉｑｕｅｉｓａｎｅｗｌｙｄｅｖｅｌｏｐｅｄｍｅｔｈｏｄｆｏｒｔｉｍｅｓｅｒｉｅｓａｎａｌｙｓｉｓ(Ｈｕａｎｇｅｔａｌ.,1 998) .Ｔｈｉｓｍｅｔｈｏｄｉｓｓｕｉｔａｂｌｅｆｏｒａｎａｌｙｚｉｎｇｎｏｎｌｉｎｅａｒａｎｄｎｏｎ ｓｔａｔｉｏｎａｒｙｐｒｏ ｃｅｓｓｂａｓｅｄｏｎａｎｅｍｐｉｒｉｃａｌａｐｐｒｏａｃｈａｎｄｐｒｏ ｖｉｄｅｓａｐｒｅｃｉｓ…     

一类具有样条和逼进性质的n次代数曲线

在平面上,将形如（1－u）l1l2－ul0~2=0的二次曲线族中的l0~2换成l0~n,得到一类形如（1－u）l1l2－ul0~n=0的n次代数曲线,文章通过对此类曲线正则性、凸性的研究,给出了此类曲线在插值和逼进等方面的应用．     

Analysis of a load application point in spline coupling teeth

The objective of this paper is to investigate the position of the resultant force in involute spline coupling teeth due to the contact pressure distribution for both ideal and misaligned conditions. In general, spline coupling teeth are in contact all along the involute profile and the load is far from uniform along the contact line. Theoretical models available in publications consider the resultant contact force as it is applied at the pitch diameter, and this study aims to evaluate the error introduced within the confines of a common approximation environment. This analysis is carried out through using finite element method （FEM） models, considering spline couplings in both ideal and misaligned conditions. Results show that the differences between the load application diameter and pitch diameter are not very obvious in both ideal and misaligned conditions; however, this ap- proximation becomes more important for the calculation of the tooth stiffness.     

虚拟现实环境下软管布线仿真

针对软管变形的特点及影响因素,提出一种面向虚拟现实环境布线应用的软管几何变形数学建模算法.采用Gossard变形能方程和双段三次开放均匀B-样条曲线建立软管变形的能量函数;然后分别阐述几何约束和连续性问题处理方法;而后通过能量函数的极小化求解,获得曲线控制点位置,从而实现对软管变形数学建模;最后通过实验验证上述算法的正确性.这种算法计算量小,模型逼真,能够在不违背软管物理特性的基础上实现对软管形状进行控制,对拓展虚拟现实技术的应用范围有重要意义.