有向距离

An algebraic B-spline curve fitting algorithm based on the signed distance field is proposed in this paper.

提出了一种以代数B-样条曲线为表达形式、基于有向距离场的隐式曲线重建方法。

The parameter space is one-dimension and the geometric meaning of the parameter is the cross ratio of four directional distances between a point and four lines.

其参数空间是一维的，参数的几何意义是点到四条直线的有向距离之交比。

It is defined by the direct distance between image surface and a threshold surface which should be constructed first.

通过构造一个阈值曲面，用图像曲面与阈值曲面间的有向距离来定义符号距离曲面。

When the consistency is checked, the "distance diagram"is employed. It is concluded that the axioms of a description satisfies the consistency iff there are no negative directed cycles in the distance diagram.

在验证ISITL描述的一致性时采用"距离矢量图"，并认为一个ISITL描述满足一致性当且仅当其距离矢量图上不存在负矢量和的有向回路。

The overcutting on tool end is checked via comparing the tool radius with the circumradius or the radius of inscribed circle, and the touch interference of tool body based on the symbol of the vector distance from the triangle vertex to the tangent plane of tool body column.

在曲面加工的无干涉路径规划中，通过恰当选择刀具初始位置避免了接触点处的曲率干涉；通过比较刀具半径与曲面上三角片外接园半径的大小即可判断刀具底面干涉；而根据三角片顶点与刀杆切平面的有向距离的正负来判断刀杆碰撞干涉。

By studying theory of the least squares, the paper defined normal angles of polygon and presented a computation method of the distance between two polygons.

基於最小二乘原理，提出了多边形法向的概念。在此基础上，提出了多边形间有向距离的计算方法。

A self-drilling anchor (10) for use in a friable material (1) comprises a body (12) having an axis (13), a flanged rear end (14), a drilling front end (16) and a generally cylindrical portion (18) therebetween having an outer surface (20) with a thread (22) disposed thereon, wherein the body forks, beginning at a predetermined distance from the flanged rear end, into a first leg (24) and a second leg (26), the first leg extending forwardly into a drilling tip (28) and having a generally rearward facing shoulder (30) angled obtusely outwardly with respect to the axis, wherein the body (12) has an axial bore (32) for receiving an elongate fastener (2), the axial bore (32) extending substantially through the flanged end (14) and the generally cylindrical portion (18) and leading to the generally rearward facing shoulder (30), wherein the anchor (10) has a drilling mode wherein the second leg (26) nests behind the generally rearward facing shoulder (30) of the first leg (24), and an anchoring mode wherein the legs are pivoted apart from one another.

一种用于易碎材料(1)中的自攻螺钉(10)，包括：主体(12)，其具有中心轴(13)、带有凸缘的后端部(14)、用于钻孔的前端部(16)和位于所述后端部和前端部之间的通常为圆柱状的部分(18)，所述圆柱状部分(18)的外表面(20)上布置有螺纹(22)，其中主体从距离带有凸缘的后端部的预定的距离处开始分叉为第一腿(24)和第二腿(26)，第一腿向前伸入钻孔尖端(28)，并且具有相对于中心轴向外成钝角的通常面向后的肩部(30)，主体(12)具有容纳细长状紧固件(2)的轴向孔(32)，轴向孔(32)基本延伸穿过带有凸缘的端部(14)和通常为圆柱状的部分(18)，并且通向通常面向后的肩部(30)，螺钉(10)具有钻孔状态和固定状态，在钻孔状态，第二腿(26)套在第一腿(24)的通常面向后的肩部(30)之后，并且在固定状态，腿彼此转动分离。

The success of star map match is judged according to compute the EMD distance of two stars.

针对现有的识别算法存在识别速度慢，识别成功率不高，提出了一种新的星图识别算法，该算法根据恒星星等，利用锚定的方法，使待识别星图中的星落于导航星图中的星的ε邻域，对于未落于ε邻域的星，建立有向赋权二部图，进行完美匹配，根据计算星对之间EMD距离，来确定星图的匹配是否成功。

In the project, we found a method for designing a family of 4-optimal double loop networks, established some sharp upper bounds of forwarding indices, distance domination nember, the edge-connectivity and the sharp upper bounds of wide-diameter and fault-tolerant diameter of Cartesian product graphs, the lower bounds of restricted edge-connectivity of digraphs and a sufficient and necessary condition for the restricted edge-connectivity of a graph to be equal to the restricted connectivity of its line graphs; raveled pancyclicity and panconnectivity and obtained the exact values of the mentioned parameters for some well-known networks.

本项目给出最优双环网络的设计方法，找到4紧优双环网络无限族，建立了路由转发指数紧的界，确定了笛卡尔乘积图的边连通度的表达式，宽直径和容错直径紧的上界，给出有向图限制边连通度的下界和无向图的限制边连通度等于它的线图限制点连通度的充要条件，对一些著名的网络确定了上述参数的精确值，讨论了宽直径和容错直径之间的关系，解决了超立方体某些变型网络的泛圈性和泛连通性，得到距离控制数的紧的上界。

But overall, China's tourism industry is still in a low-consumption, mass, low-level, short-distance travel conditions, and began to travel to developed countries the trend of structural changes.

但总的来说，我国的旅游业仍然处于一种低消费、大众化、低层次、距离短的旅游状况，并开始有向发达国家旅游结构变化的趋势。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。