限制在光滑参数曲线上的С~1曲面插值

给出了一种限制在光滑参数曲线上的C1曲面插值方法.首先通过曲线参数化,建立从曲线到实参数轴的一个一一映射,将限制在曲线上的曲面插值问题转化为实参数轴上的一元插值问题,然后采用范数极小的方法给出参数轴上的一元C1插值函数,再将此插值函数映射到原曲线上即得到限制在参数曲线上的插值函数.理论推导和图形实例显示表明该方法具有逼近效果好的优点.     

Parameterization for fitting triangular mesh

In recent years, with the development of 3D data acquisition equipments, the study on reverse engineering has become more and more important. However, the existing methods for parameterization can hardly ensure that the parametric domain is rectangular, and the parametric curve grid is regular. In order to overcome these limitations, we present a novel method for parameterization of triangular meshes in this paper. The basic idea is twofold: first, because the isotherms in the steady temperature do not intersect with each other, and are distributed uniformly, no singularity (fold-over) exists in the parameterization; second, a 3D harmonic equation is solved by the finite element method to obtain the steady temperature field on a 2D triangular mesh surface with four boundaries. Therefore, our proposed method avoids the embarrassment that it is impossible to solve the 2D quasi-harmonic equation on the 2D triangular mesh without the parametric values at mesh vertices. Furthermore, the isotherms on the temperature field are taken as a set of iso-parametric curves on the triangular mesh surface. The other set of iso-parametric curves can be obtained by connecting the points with the same chord-length on the isotherms sequentially. The obtained parametric curve grid is regular, and distributed uniformly, and can map the triangular mesh surface to the unit square domain with boundaries of mesh surface to boundaries of parametric domain, which ensures that the triangular mesh surface or point cloud can be fitted with the NURBS surface.     

A New Digital Multilevel Proxy Signature Scheme Based on Elliptic Curve Cryptography

Based on the analysis of elliptic curve digital signature algorithm（ECDSA）,aiming at multilevel proxy signature in which the original signer delegates the digital signature authority to several proxies and its security demands, a new multilevel proxy signature scheme based on elliptic curve discrete logarithm problem （ECDLP） is presented and its security are proved.     

基于椭圆曲线公钥密码体制的手机短信加密方案

介绍了手机短信系统的特点以及椭圆曲线公钥密码体制,提出了一种基于椭圆曲线上离散对数问题的手机短信加密方案,实验表明:其安全性高,不易攻破,形式简单,运行速度快.     

Sn-15%Pb合金电脉冲孕育处理效果时间相关性研究

采用Sn-15%Pb合金作为实验材料,在保持熔体过热90℃的条件下,对其进行不同时间的电脉冲孕育处理.利用金相组织观察和热分析等手段来评价电脉冲孕育处理对合金凝固组织和凝固过程的影响.结果表明:经电脉冲孕育处理后,Sn-15%Pb合金凝固组织发生了明显的变化,凝固组织中的富Sn初生相形态从树枝晶转变为颗粒状;与凝固组织的变化相对应,合金的凝固过程也发生了明显的改变,初生相形核的最低温度有较大幅度的提高;但随着电脉冲处理时间的延长,凝固组织中粒状晶的数量总体呈现出"少-多-少-多"的周期性变化规律;与之相对应,初生相形核温度的变化也随电脉冲孕育处理时间的延长呈现出周期性.     

面向三维参数化女性人台构建的胸部特征数据测量方法

为了在计算机中实现三维参数化人台的显示与调节，并能真实地反映人体各围度曲线的变化，本文通过三维激光非接触式人体扫描仪，对300余名在校女大学生进行测量，获取了大量的人体长度和围度方向的测量数据．通过对胸部测量数据的统计分析，选择了能够反映女性胸部形状和形态的5个水平截面，提取了影响曲线围度形状的特征点．对特征点坐标与身高及反映胸部体型的参数进行了多元线性回归分析，得出构成胸部各围度曲线的特征点坐标变化规律，实现了女性参数化人台胸部曲线的真实模拟．     

Improved Non-Sieving Quadratic Sieve

In this paper, we give about prime numbers and Blum two theorems and one guess integers.We prove the two theorems about Blum integers.Combining the guess with the primitive non-sieving quadratic sieve,we proposed a improved non-sieving quadratic sieve（INQS）.In INQS,we not only reduce the times of squares and modulo n, but also imply another important conclusion,that is,we don＇t need to find the greatest common divisor of two integers as we do in PNQS.By some examples,we compare it with the primitive non-sieving quadratic sieve（PNQS）. It＇s faster to factor a integer by using improved non-sieving quadratic sieve than the primitive one.     

一种基于椭圆曲线的授权签名方案

授权签名是代理签名的一种特殊形式.本文在椭圆曲线签名的基础上提出了一种新的授权签名协议,该协议比已有的授权签名协议更安全、更简单有效.     

非圆齿轮-连杆型函数发生器的机构综合

给出了非圆齿轮－连杆型函数发生器综合时必须遵循的机构学制约条件，并提出了确定连杆机构处于极限位置时的非圆齿轮角速比的基本公式。以具有等速急回特性的曲柄滑块机构型函数发生器的机构综合为例，研制了有实用价值的非圆齿轮－连杆型函数发生器机构综合CAD软件。     

金佛山甑子岩物种多样性保护研究

用稀疏曲线法、丰富度指数、多样性指数和均匀度指数分析了金佛山甑子岩植物群落的物种丰富度、多样性和均匀度。结果表明：该地区距离人群居住地越近、海拔越低的地方其植物群落的丰富度指数、多样性指数和均匀度指数越低，并且该地区植物群落处于严重退化状态，说明该地区植物群落的退化主要是由于过度放牧和滥伐造成的。