拟平面曲线

A new curvature-based algorithm in free-form curve fitting was proposed to fit a 2D NURBS profile with an arc spline ,where a new form of curvature formula with matrix representation was also proposed,and then the arc spline tool path with G~(1) continuity was generated.

给出了一种平面曲线轮廓的圆弧样条拟合及刀具路径生成算法，该算法面向零件轮廓的光顺性刀具路径生成，通过应用曲线的曲率关系，对以NURBS表示的被拟合自由曲线按参数递增的方向用G1连续的圆弧或直线段逐段拟合，并生成相应的圆弧样条刀具路径，从而实现零件曲线轮廓表面的光顺加工。

In this report, based on initial data array of annual increase of growing stock, GM(1, 1) enveloping grey surface is set up, and predictive curve is obtained by fitting initial data with differential equation according to mecha- nism of GM model. Scientific basis has been provided for determining the optimum annual cutting norm.

为合理采伐利用林木资源，本文根据全区林木年蓄积增长量原始数据列，建立GM（1，1）包络灰平面，并按GM模型建模机理，用微分程拟合原始数据，求得预测曲线，使预测值落在栽一范围内，为确定最佳年采伐限额提供了科学依据。

In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.

这章具体研究了基于三种极化散射特性描述的相应的目标识别方法：①基于极化参数平面描述的目标识别方法，将目标回波极化状态投影到以极化椭圆参数，即椭圆率角ε和倾角τ表征的极化状态平面上，参数随观测频率的变化就形成了图，根据图的变化特点构造了目标的多维极化特征空间，并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构；②基于Poincare极化球面描述的目标识别方法，采用Stokes矢量表征目标回波的极化状态，并将其投影到描述极化状态的Poincare极化球面上，定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息，提取了准方位不变性的目标极化特征，最后设计了目标的识别器结构；③基于频率敏感性描述的目标识别方法，通过在Poincare极化球面上所定义的极化状态距离的概念，研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题，获得了在极化状态距离下的频率分布特性曲线，采用最小二乘估计曲线拟合方法，它既用于极化特征的降维，同时又直接将拟合参数作为目标的分类特征。

The yield curve in q direction in π plane is a curving triangle that obtained from the true-triaxial test data of Chongqing red clay.

用重庆红粘土真三轴试验数据拟合得到偏平面上的剪切屈服曲线为一曲边三角形。

In this paper, a new tracing algorithm is presented for planar curve reconstruction based on the regular distribution property of the point set.

根据实际采样中离散点分布相对集中的特点，给出了一个用简单曲线拟合平面上的无序点集的跟踪算法。

Four main types of spatial binary links are investigated in details for kinematic synthesis both in precision-position synthesis and multi-position synthesis. In terms of the invariants of spherical curve and cylindrical curve, the mathematical models of adaptive fitting sphere and cylinder are constructed by means of the saddle-point programming.

再次，根据常见空间机构运动副组合的约束曲线与约束曲面的曲率理论，阐述了空间机构运动综合的基本要素及其不变量拟合理论与方法，研究了有限位置和多位置情况下，自适应综合方法在空间S-S、C-S、C-C和S-C四类二副杆组运动综合中的应用，实现了自适应综合方法从平面到空间的扩展。

The fitting algorithm of product section and overall unit performance curves, the plane interpolation algorithm and mathematical method of physical property parameter of various single gas are mainly discussed, and also dealt with the technique of information integration on developing environment and data base application etc.

介绍了设计开发的风机性能信息系统，着重论述了产品段性能曲线和整机性能曲线的拟合算法、各种单一气体物性参数的平面插值算法等数学方法，还涉及到开发环境的信息集成和数据库的应用等技术。

The fitting algorithm of product section and overall unit performance curves, the plane interpolation algorithm and mathematical method of physical property parameter of various single gas are mainly discussed, and also dealt with the technique of information integration on developing environment and data base application etc.

风机性能信息系统的设计开发摘要：介绍了设计开发的风机性能信息系统，着重论述了产品段性能曲线和整机性能曲线的拟合算法、各种单一气体物性参数的平面插值算法等数学方法，还涉及到开发环境的信息集成和数据库的应用等技术。

In addition, many studies of patients with AVN showed plenty of special characteristics,such as age distribution and bone quality.Objective:To study the geometric features of proximal femur for the Chinese AVN population,in order to prove the existence of special characteristic of proximal femur for the disease and then develop an AVN-specialized stem evaluated by a validated finite element analysis.Methods:1.The author investigated the standard X-ray data of 127 cases(179 hips) with definite diagnosis of AVN to provide anatomical references for this disease.At the same time,we conducted a meta-analysis of anatomical studies of normal proximal femur data,including the section of LT+20,LT,LT-20 and CFI to identify the potential difference between AVN and normal population.

方法1、通过研究AVN患者标准X线正、侧位片127例(179髋)，获得股骨近端的解剖学数据，利用荟萃分析的方法比较AVN患者股骨近段髓腔特征平面(LT+20，LT，LT-20)及CFI的改变与以往研究数据的差异，并利用创伤性FNF患者资料代替正常人股骨数据进一步比较髓腔前、后、内、外四条曲线段上的差异。2、通过结合现代CAD技术，将内、外、前、后曲线拟合到AVN柄的外形上，选用短柄假体设计，近段设计利用AVN患者骨髓腔CT相对应位置的断面进行修正，设计AVN人工股骨柄。3、计算机三维有限元分析：①使用CAD软件SolidWorks和有限元软件Ansys所建立的髋关节股骨侧假体置换后的三维有限元模型。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了