期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
Self-Expanded Clustering Algorithm Based on Density Units with Evaluation Feedback Section 被引量:1
1
作者 YU Yongqian ZHAO Xiangguo CHEN Hengyue WANG Bin YU Ge WANG Guoren 《Wuhan University Journal of Natural Sciences》 CAS 2006年第5期1069-1075,共7页
This paper presents an effective clustering mode and a novel clustering result evaluating mode. Clustering mode has two limited integral parameters. Evaluating mode evaluates clustering results and gives each a mark. ... This paper presents an effective clustering mode and a novel clustering result evaluating mode. Clustering mode has two limited integral parameters. Evaluating mode evaluates clustering results and gives each a mark. The higher mark the clustering result gains, the higher quality it has. By organizing two modes in different ways, we can build two clustering algorithms: SECDU(Self-Expanded Clustering Algorithm based on Density Units) and SECDUF(Self-Expanded Clustering Algorithm Based on Density Units with Evaluation Feedback Section). SECDU enumerates all value pairs of two parameters of clustering mode to process data set repeatedly and evaluates every clustering result by evaluating mode. Then SECDU output the clustering result that has the highest evaluating mark among all the ones. By applying "hill-climbing algorithm", SECDUF improves clustering efficiency greatly. Data sets that have different distribution features can be well adapted to both algorithms. SECDU and SECDUF can output high-quality clustering results. SECDUF tunes parameters of clustering mode automatically and no man's action involves through the whole process. In addition, SECDUF has a high clustering performance. 展开更多
关键词 clustering clustering result evaluating density unit hillclimbing algorithm
下载PDF
Excited state refraction of C_(70)/toluene studied by using 4f coherent imaging system with phase object 被引量:1
2
作者 刘南春 石光 +1 位作者 杨俊义 宋瑛林 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第1期304-309,共6页
Dynamic nonlinearities of C70/toluene solution are measured and analysed by an improved picosecond timeresolved pump-probe system based on a nonlinear imaging technique with phase object. The photophysical parameters ... Dynamic nonlinearities of C70/toluene solution are measured and analysed by an improved picosecond timeresolved pump-probe system based on a nonlinear imaging technique with phase object. The photophysical parameters are determined by the five-level model, which is adopted to interpret the experimental data. The change of refraction index per unit density of the excited state obtained by a numerically simulation is a critical factor to determine the nonlinear behaviour of C70 in picosecond time regime. 展开更多
关键词 4f system excited state refraction C70/toluene solution refraction index per unit density
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部