查询词典 one parameter family of curves

ABSTRACT This paper summarizes our researches on two key techniques in curve and surface modeling-the geometric approximation techniques and the geometric interpolation techniques. The former includes three types of geometric approximation techniques: Hybrid polynomial approximation to rational curves and surfaces, offset curves and surfaces approximation, interval Bézier curves and surfaces approximation. The latter includes a series of algorithms for shape blending modeling: the MSI algorithm for shape blending between space polylines or trees, the MSI algorithm for shape blending between triangular meshes, and skeleton-based shape blending algorithms using triangular decomposition and star-shape decomposition.

本文是作者对曲线曲面造型中两类核心技术几何逼近技术和几何插值技术的研究成果的总结，其中前者包括有理曲线曲面的Hybrid多项式逼近、等距曲线曲面逼近和区间曲线曲面逼近等三类几何逼近方法；后者包括用于形状混合造型的几何插值方法的一系列算法：空间多边形形状混合的MSI插值算法、三角网格形状混合的MSI插值算法、树的形状混合的MSI插值算法以及基于骨架树形状混合的三角剖分算法和星形剖分算法。

With the shape parameters, the trigonometric polynomial curves can approach more to the quadratic Bézier curves or to the given control polygon than the quadratic Bézier curves.

由三个控制顶点生成的曲线具有与二次Bézier曲线类似的性质，但具有比二次Bézier曲线更好的逼近性。

Joint behavior of beam and column is the key of entire structure.This paper uses finite elemnt analyzing software ANSYS to analyze the bearing mechanics of joint under monotonic load and periodic load,and gets load-displacement curves,viscosity curves and frame curves.The paper mainly analyzes how axis-push ratio,gradation of concrete,plate layout and steel type to affect tensibility performance and viscosity feature of joint.The results indicate that concrete-filled squar tube column has good tensibility performance and dissipative ability.

梁柱节点的性能是影响结构整体性能的关键，而目前对方钢管混凝土柱—钢梁节点抗震性能的研究工作尚不完善，本文通过有限元软件ANSYS来分析方钢管混凝土柱—钢梁节点，研究节点区在单调荷载和低周反复荷载作用下的受力机理，得节点区的荷载位移曲线、滞回曲线及骨架线；着重分析方钢管混凝土柱的轴压比、混凝土等级，隔板形式和钢材型号在低周反复荷载作用下对节点延性和耗能等抗震性能指标的影响。

When t=1/2, Path of the C-curves and H-curves ofdegree two and three are lines, but not for the Path of degree four, weneed more about the control polygon. Paths are commonly curves. Butthe reference [38] pointed out that they can closely be approximated bylines. By this method we can get a C-curve passing a given point easily.

一般情况下，C曲线族的Path也是曲线，文献[38]以三次C曲线为例，提出用直线进行近似，应用这一方法，我们可以简洁的求出过一定点的C曲线，只要给定的点在C曲线族的范围内，则可以首先求出过这一点的C曲线族的Path，然后可以确定过这一点的C曲线的形状参数α，以及曲线参数t.H曲线的情况与C曲线类似。

By using hyperbolas to fit axial curves, considering the maximal error of the fitting curves as the objective function, the optimal fitting hyperbola is obtained and the maximal error of fitting curves is minimal after optimization.

通过双曲线来拟合齿向曲线，使拟合曲线的最大误差为目标函数，利用优化的方法，使最大误差最小，得到最优的拟合双曲线，从而加工出所需要的齿形。

In practice, we often need observe characteristic curves of all apparatus. These curves are hardly drawed by hand directly, but using MATLAB protracts the curves rapidly and briefly.

在实际中，我们常常需要观察各种器件特性曲线，这些曲线很难用手直接画出，利用 MATLAB 则可以较快捷，简单的绘制这些曲线。

In order to investigate how randomness of concrete had effects on structural responses by means of experiments, authors carried out a pseudo static experiment on the same four-story 1:3 scaled model of short-leg shear wall structure. Load and displacement curves, strain curves of reinforced concrete and partial relative displacement curves were obtained.

为了从试验角度研究混凝土随机性对结构反应的影响，以4片相同的4层1：3比例缩尺模型的短肢剪力墙结构为研究对象，进行了拟静力试验研究，得到了荷载－位移曲线、混凝土和钢筋的应变曲线及墙体局部相对位移曲线。

For example, Keyfitz made the classification of the bifurcations in one state variable, without symmetry up to codimension 7; Golubitsky and Schaeffer obtained the classification of the bifurcation problems in one state variable with Z_2 symmetry, in one parameter up to codimension 3; Golubitsky and Roberts studied the classification of degenerate Hopf bifurcation in two state variables with dihedron D_4 symmetry, in one parameter up to topological codimension 2; Melbourne obtained the classification of bifurcations in three state variables with octahedral symmetry, in one parameter, up to

需要指出的是以上研究均没有考虑分歧参数的对称性，Futer，Sitta和Stewart的工作虽然考虑了分歧参数的对称性，但仅限于分歧参数与状态变量具有相同的对称性，他们得到了状态变量与分歧参数均关于二面体群D_4对称，拓扑余维数不大于1的分歧问题的分类。高守平和李养成则讨论状态变量和分歧参数均具有对称性且对称性可以不同的分歧问题，并给出了状态(来源：A770707BC论文网www.abclunwen.com)变量关于二面体群D_4对称，分歧参数关于S~1对称，拓扑余维不超过1的分歧问题的分类。本文第一章讨论两个状态变量关于二面体群D_3对称，两个分歧参数关于O(2)对称的分歧问题，给出了该类分歧问题在非退化条件q(0)≠0下所有情形的分类与相应的识别条来源：AdadaBC论文网www.abclunwen.com

The cubic algebraic curves (the Bezier curve and B style curve, etc belong to the parameter curve) is apter to realize the curve transition and fitting to dispersed data than the cubic parametric curves.

比如参数曲面与平面的交线就是一条平面代数曲线；平面参数曲线的等距曲线也是一条代数曲线。

This algorithm firstly translates arbitrary parameter curves into the piecewise cubic-degree Bezier curves, then using the properties of Bezier curve we can get the tangent vector and the normal vector of every point on the approximation curve, and calculate the approximating offset curve.

此算法先将任意形式的参数曲线转化成分段三次Bézier曲线，利用Bézier曲线的性质容易得到逼近曲线的切向量和法向量，从而计算出其等距逼近曲线。

Diabetes is a social disease that affects several million people worldwide.

糖尿病是一个社会性疾病，全世界有数百万人罹患此病。

I'll call you on Friday to see if we can reschedule our luncheon meeting at your convenience.

我星期五会给您打电话在您方便的时候我们重新安排我们的午餐约会。