The completion problems of partial inverse m - matrix for 3 - chordal graph are discussed by using graph theory and the completion theorems for 3 - chordal graphs are presented in this paper 摘要利用图论的相关知识，在1 -弦图、 2 -弦图完备的基础上探讨了3 -弦图的完备问题，给出3 -弦图的完备定理。
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Through the use of the multivalued directed angle and its related notions , it is given the sufficient and necessary conditions when the three chordal circles based on the three sides of a triangle as their chords share the same point 摘要利用多值有向角及其相关概念，给出了以三角形每边为弦各作一圆所得三圆共点的充要条件，推广了已有结论。
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Data preprocessing refers to the process of polygonization , smoothing , decimation and registration . the flow and main steps of data preprocessing are described here . several specific cases , for example the sampling method based on chordal deviation , the feature based registration , are discussed 本文研究和讨论了点云预处理的基本流程和主要步骤，研究点云光顺的高斯滤波，中值滤波和平均滤波方法、点云精简的弦高差算法和多视点云特征对齐的方法。
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An isolated point " s statistic excluding method is proposed in this paper to eliminate crassitude error in clouding data , which include plenty of oddity data . the method based on the distance between two neighbour points can eliminate the data beyond normal distribution . a error limitation of angle and chordal highness method is used to filtrate clouding point 针对大量含奇异点的数据点云，本文提出了剔除粗大误差的孤立点统计排异法，该方法根据对相邻点距离的统计，剔除在正态分布以外的点；对大量数据的精减，利用角度和弦高的最大允许偏差法进行点云精减。
