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基于多维网格空间的改进K-means聚类算法 被引量:17
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作者 邵伦 周新志 +1 位作者 赵成萍 张旭 《计算机应用》 CSCD 北大核心 2018年第10期2850-2855,共6页
K-means算法是被广泛使用的一种聚类算法,传统的K-means算法中初始聚类中心的选择具有随机性,易使算法陷入局部最优,聚类结果不稳定。针对此问题,引入多维网格空间的思想,首先将样本集映射到一个虚拟的多维网格空间结构中,然后从中搜索... K-means算法是被广泛使用的一种聚类算法,传统的K-means算法中初始聚类中心的选择具有随机性,易使算法陷入局部最优,聚类结果不稳定。针对此问题,引入多维网格空间的思想,首先将样本集映射到一个虚拟的多维网格空间结构中,然后从中搜索出包含样本数最多且距离较远的子网格作为初始聚类中心网格,最后计算出各初始聚类中心网格中所包含样本的均值点来作为初始聚类中心。此法选择出来的初始聚类中心与实际聚类中心拟合度高,进而可据此初始聚类中心稳定高效地得到最终的聚类结果。通过使用计算机模拟数据集和UCI机器学习数据集进行测试,结果表明改进算法的迭代次数和错误率比较稳定,且均小于传统K-means算法测试结果的平均值,能有效避免陷入局部最优,并且聚类结果稳定。 展开更多
关键词 K-MEANS算法 聚类算法 初始聚类中心 多维网格空间 均值点
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SDOG-based multi-scale 3D modeling and visualization on global lithosphere 被引量:12
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作者 YU JieQing WU LiXin +1 位作者 ZI GuoJie GUO ZengZhang 《Science China Earth Sciences》 SCIE EI CAS 2012年第6期1012-1020,共9页
The structure of global lithosphere is very important to the scientific researches of tectonic movement, geodynamic process, mantle convection, resource exploration, and disaster prevention and reduction. Three-dimens... The structure of global lithosphere is very important to the scientific researches of tectonic movement, geodynamic process, mantle convection, resource exploration, and disaster prevention and reduction. Three-dimensional (3D) spatial modelling and visualization is an effective tool for lithosphere researches. However, both the isoline/profile methods and the Euclidean-based 3D modelling methods cannot meet the requirement of real 3D modeling of global lithosphere, whereas the recently developed global 3D grid methods have some defects on grid design, such as grid shrinkage, overlapping, non-orthogonality, and nonlatitude-longitude consistency. In this paper, Spheroid Degenerated-Octree Grid (SDOG), a non-overlapping, non-shrinking, orthogonal, latitude-longitude consistent grid in the spheroidal manifold space, was chosen as the basic grid for global lithosphere 3D modeling and visualization. The SDOG-based methods of spatial representation and modelling of lithosphere were proposed. A multi-scale model of lithosphere was designed, and the multi-scale modeling and multi-mode visualization were realized at the full advantages of SDOG in multi-hierarchical and multi-resolution and the properties of lithosphere in multi-semantic. It shows that (1) the SDOG-based method has not only overcome the defects of the current global 3D grid, but also reflected the spherical features of lithosphere more realistically and naturally than the traditional methods, providing a novel solution for global modeling, numeric simulating, and data sharing of lithosphere; and (2) more detailed plates division, more precise geo-layer structure, plates boarder and surface concave-convex, and more rich lithosphere properties are revealed as the scale-model moves on. 展开更多
关键词 Spheroid Degenerated-Octree Grid (SDOG) LITHOSPHERE 3D manifold modeling VISUALIZATION global 3D grid
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