空间曲线

An image conic can be the projection of either a planar conic or silhouette of a conicoid. We show that at least three images, taken from the same position with different camera orientations, of two planar conics, or two conicoids, or one conic and one conicoid, are needed for the calibration, and a closed-form solution can be obtained. Our new conic based calibration technique requires no knowledge of camera's orientations, and relies solely on image correspondences.

在不同的方位拍摄三幅或三幅以上图像，每幅图像至少包含两个空间平面二次曲线、或两个二次曲面、或一个平面二次曲线与一个二次曲面的投影，利用图像之间的二次曲线对应关系，可以确定摄像机的内参数矩阵，同时可以获得摄像机不同方位之间的旋转矩阵。

The tangent space and normal space of the robot motion curve is constructed by using Newton-Euler orthogonal method, which satisfies the restrictions of linear and angular momentum conservation of free-floating space robot system. An analytical expression of joint actuation torque in the floating state is given by using this method.

根据空间机器人自由漂浮状态时系统动量守恒的特点，采用Newton-Euler正交方法构建了满足系统动量守恒约束条件的空间机器人运动曲线法空间与切空间基底，并以此基础得到了自由飘浮状态下的空间机器人关节力矩的显式表达式。

A curve coordinate system which is suitable for variable height curved box-girder were established. The flexure, torsion and distortional warping displacement functions were established, and the strain-deformation equations were obtained, a spatial finite element analysis method of trapeziform cross section variable-curvature box-girder with vertical symmetrical axis was also presented.

建立适合于变高度曲线箱梁的曲线坐标系，推导了变曲率、变高度箱梁弯曲、翘曲扭转和畸变的位移方程和应变-位移关系式，提出了具有一个竖直对称轴的变高度变曲率曲线箱梁的薄壁曲梁空间分析有限元方法。

In this paper, based on the vector analysis and the warping torsion theory of curved thin-walled girders, a set of governing differential equations for the non-uniform torsion of thinwalled spatial helicoid girders is developed.

本文应用矢量运算及薄壁曲线梁翘曲扭转理论，建立了空间螺旋形的薄壁曲线梁基本微分方程，用初参数法解出翘曲扭转微分方程，为进一步进行薄壁螺旋曲线梁的空间结构分析提供理论基础。

By projecting 3D models into 1D smooth principal curves, equally segmentation and sampling along the length of curve are implemented to extract shape feature vectors, then one can retrieve 3D model according to the matching result of shape feature vectors of 1D manifold.

本文将三维网格模型，投影为三维的光顺主曲线；通过对主曲线沿弧长方向的均匀分割采样，提取主曲线的空间位置和姿态等形状特征；最后通过形状描述向量的比较实现了对应的三维模型检索。

Around the topic, the weak points of the traditional platform is analyzed first, such as complex arithmetic, long calculating time, high needs of hardware and so on. A real time control method based on virtual simulation is suggested to separate the complex positive/negative calculation of space kinematic and real time motion control. And a"3-2-1"type 6DOF platform is designed with the reference of the MAST (Multi-Axis Shaking Table) of MTS. The kinematic and dynamic calculation of the platform is finished. According to the calculating result, the control system of the"3-2-1"type 6DOF platform including 6 linear servo electric cylinders is designed and constructed. And the professional software Pro/E is used to do the 3D model and 6DOF motion simulation of the platform. The motion curves of the pistons of the 6 cylinders are exported with the simulation. At last the control software is programmed with Microsoft Visual Basic 6.0 and realizes the functions with the commands of GE series motion controllers. When loading the motion curves exported with the simulation, every cylinder can follow the curve very well and the platform realizes the hoped 6DOF motion.

围绕选题，本论文首先分析了传统的运动平台控制方法所存在的算法复杂、解算耗时长、硬件需求高的缺点，提出了一种基于虚拟仿真的实时控制方法，该方法将复杂的空间运动学正、反解与实时运动控制相分离；之后，参考MTS公司的MAST多轴振动平台，设计了新型的"3-2-1"型六自由度平台，并进行了运动学及动力学计算，根据相关计算结果，设计与搭建了包括驱动6个直线伺服电动缸在内的"3-2-1"型六自由度平台控制系统；接着，使用Pro/E对"3-2-1"型六自由度平台进行了三维建模和六自由度运动学仿真，并由仿真直接获得了6个直线伺服电动缸的活塞杆的相应运动曲线；最后使用Microsoft Visual Basic 6.0编写了控制软件界面，通过调用GE系列运动控制卡的各种命令函数实现了控制系统的相关功能，而当加载仿真得到的各缸运动曲线后，每缸均能很好地跟踪输入曲线，使平台实现了期望的多自由度运动。

With Hilbert space filling curve and latent semantic index, MLSQ maps similar data objects in high dimension semantic space into an adjacent range in one dimensional value space, and considers every data object sequence number in one dimensional space as a key. MLSQ distributes the keys to adjacent nodes of structured P2P systems. By embedding the process of searching data points of HSFC into the nodes of structured P2P networks and using the data search mechanism of networks, MLSQ can facilitate to search the data objects in accordance with query requirements.

该方法利用Hilbert空间填充曲线和潜在语义索引，将高维语义空间中相似的数据对象映射到一维数值空间中的邻近区域中，并以每个数据对象在一维数值空间中的序号作为键，将数据对象的索引分布到有组织P2P网络邻近的结点上，通过将HSFC中数据点的查找过程嵌入到有组织P2P网络的结点上，再利用网络的数据查找机制，MLSQ可方便地搜索到符合查询要求的数据对象。

As to straight texels, we study the local relative coordinate equation of a light line in a texel coordinate system, and the concrete shape of light line when mapped to texel space, so that quick check could be made for the intersection of light line with hairs. This becomes the straight texel rendering method of global smoothness for all hairs and can be used to long hairs.

对于直形纹元，研究了直纹元体内光线的局部相对坐标方程，和影射到纹元空间后的具体形状，并给出拟合纹元空间中光线曲线的方法以及它投影到纹元底面的曲线的形状，以便使用快速方法判断光线与头发的相交情况，进而给出在整体上具有头发光滑效果的直纹元的绘制方法。

This controller adopts different control actions according to the phase space composed by error and error change to meet the requirements. The corresponding relations between phase space and response curve of the seven different actions of this controller are analysed and curve is studies through actions.

七态控制器是根据在偏差和偏差的变化所构成的相空间上通过不同控制作用以达到满足要求的控制器，分析此控制器的7种不同作用力在相空间和响应曲线的一一对应关系，通过作用力来研究曲线。

For the leaf area index of the three forest types, there was a similar variation trend, i.e ., increased first and decreased then, with the maximum presented in mid-July or August for Q. mongolica and J.mandshurica forests while in mid-August or September for F. rhynchophulla forest. The canopy porosity of the three forest types also had a similar variation trend, but opposite to leaf area index, being decreased first and increased then, with the minimum presented in mid-June, July, August or September. The analysis of variation coefficients of leaf area index, transmitted direct gap light, and transmitted diffuse gap light indicated that the spatial pattern of leaf area index in July-September was the main factor affecting the spatial distribution of transmitted diffuse gap light.

结果表明，3种林型的叶面积指数变化总体趋势是一致的，均呈先上升再下降的单峰曲线，蒙古栎林和胡桃楸林都是在7月中旬或8月中旬达到最大峰值，花曲柳林是在8月中旬或9月中旬达到最大峰值；3种林型冠层孔隙度的变化总体趋势也是一致的，呈先下降再上升的单峰曲线，不同样地峰值出现的时间也不同，最低峰值在6、7、8、9月中旬均有出现；通过对不同月份的叶面积指数、林下散射光、林下直射光的变异系数分析表明，7—9月叶面积指数的空间格局是影响林下散射光空间分布的主要因素。

Chrysanthemum of 10 thousand birthday is lax to edaphic requirement, with the arenaceous qualitative loam with fecund, good drainage had better.

万寿菊对土壤要求不严，以肥沃。排水良好的砂质壤土为好。

He unstepped the mast and furled the sail and tied it.

他拔下桅杆，把帆卷起，系住。