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一种适应局部密度变化的空间聚类方法 被引量:32
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作者 李光强 邓敏 +1 位作者 刘启亮 程涛 《测绘学报》 EI CSCD 北大核心 2009年第3期255-263,共9页
研究一种适应空间局部密度变化的空间聚类算法(简称ADBSC)。在该算法中,首先提出一种新的空间局部密度度量方法,即k-空间近邻最大距离,而为了表达空间局部密度变化特征,引入距离变化率概念,用于度量邻近目标间空间局部密度变化情况。然... 研究一种适应空间局部密度变化的空间聚类算法(简称ADBSC)。在该算法中,首先提出一种新的空间局部密度度量方法,即k-空间近邻最大距离,而为了表达空间局部密度变化特征,引入距离变化率概念,用于度量邻近目标间空间局部密度变化情况。然后将所有空间邻近的距离变化率小于给定变化率阈值的空间目标标记为局部密度相等,再将空间邻近的局部密度相等的空间目标聚为一类,得到空间聚类结果。并给出ADBSC算法的详细描述和计算过程。最后,通过模拟实验和实际算例,对提出的方法进行验证。结果表明,该算法能够自动适应空间位置的局部密度变化,适应不同形态的空间簇,而且比DBSCAN算法更实用。 展开更多
关键词 空间聚类 空间局部密度 空间近邻最大距离 距离变化率
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Localization of s-Wave and Quantum Effective Potential of a Quasi-free Particle with Position-Dependent Mass
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作者 JU Guo-Xing XIANG Yang REN Zhong-Zhou 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5X期819-825,共7页
The properties of the 8-wave for a quasl-free partide with position-dependent mass (PDM) have been discussed in details. Differed from the system with constant mass in which the localization of the s-wave for the fr... The properties of the 8-wave for a quasl-free partide with position-dependent mass (PDM) have been discussed in details. Differed from the system with constant mass in which the localization of the s-wave for the free quantum particle around the origin only occurs in two dimensions, the quasi-free particle with PDM can experience attractive forces in D dimensions except D = 1 when its mass function satisfies some conditions. The effective mass of a particle varying with its position can induce effective interaction, which may be attractive in some cases. The analytical expressions of the eigenfunctions and the corresponding probability densities for the 8-waves of the two- and three-dimensional systems with a special PDM are given, and the existences of localization around the origin for these systems are shown. 展开更多
关键词 position-dependent mass S-WAVE Schrodinger equation dimensionality of the space LOCALIZATION EIGENFUNCTION probability density
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