密度峰值聚类算法(Density Peaks Clustering,DPC),是一种基于密度的聚类算法,该算法具有不需要指定聚类参数,能够发现非球状簇等优点。针对密度峰值算法凭借经验计算截断距离d_c无法有效应对各个场景并且密度峰值算法人工选取聚类中心...密度峰值聚类算法(Density Peaks Clustering,DPC),是一种基于密度的聚类算法,该算法具有不需要指定聚类参数,能够发现非球状簇等优点。针对密度峰值算法凭借经验计算截断距离d_c无法有效应对各个场景并且密度峰值算法人工选取聚类中心的方式难以准确获取实际聚类中心的缺陷,提出了一种基于基尼指数的自适应截断距离和自动获取聚类中心的方法,可以有效解决传统的DPC算法无法处理复杂数据集的缺点。该算法首先通过基尼指数自适应截断距离d_c,然后计算各点的簇中心权值,再用斜率的变化找出临界点,这一策略有效避免了通过决策图人工选取聚类中心所带来的误差。实验表明,新算法不仅能够自动确定聚类中心,而且比原算法准确率更高。展开更多
Based on the data of phytoplankton surveys made in 1959, 1981-1982, 1985 -1986 and 1991-1992 in Dianshan lake, the main ecological changes in the phytoplankton association is discussed and the main results are as foll...Based on the data of phytoplankton surveys made in 1959, 1981-1982, 1985 -1986 and 1991-1992 in Dianshan lake, the main ecological changes in the phytoplankton association is discussed and the main results are as follows:1. The average annual increase of phytoplankton density generally decreased from the 1959’s to 1985, and exhibited a increasing trend after the 1990’s. The species composition tended to become simple, and there were some changes in the proportions of relative number of phytoplankton.2. The primary productivity of phytoplanktpn showed an increasing trend, and the diversity index of community showed a decreasing trend.3. The average caloric value and standing crop of energy of phytoplankton were 11.61 KJ.g-1 DM and 139.82 KJ.m-2, respectively: their seasonal change laws were somewhat different. The energy conversion efficiency of total radiation by phytoplankton averaged 0. 68%.展开更多
文摘密度峰值聚类算法(Density Peaks Clustering,DPC),是一种基于密度的聚类算法,该算法具有不需要指定聚类参数,能够发现非球状簇等优点。针对密度峰值算法凭借经验计算截断距离d_c无法有效应对各个场景并且密度峰值算法人工选取聚类中心的方式难以准确获取实际聚类中心的缺陷,提出了一种基于基尼指数的自适应截断距离和自动获取聚类中心的方法,可以有效解决传统的DPC算法无法处理复杂数据集的缺点。该算法首先通过基尼指数自适应截断距离d_c,然后计算各点的簇中心权值,再用斜率的变化找出临界点,这一策略有效避免了通过决策图人工选取聚类中心所带来的误差。实验表明,新算法不仅能够自动确定聚类中心,而且比原算法准确率更高。
文摘Based on the data of phytoplankton surveys made in 1959, 1981-1982, 1985 -1986 and 1991-1992 in Dianshan lake, the main ecological changes in the phytoplankton association is discussed and the main results are as follows:1. The average annual increase of phytoplankton density generally decreased from the 1959’s to 1985, and exhibited a increasing trend after the 1990’s. The species composition tended to become simple, and there were some changes in the proportions of relative number of phytoplankton.2. The primary productivity of phytoplanktpn showed an increasing trend, and the diversity index of community showed a decreasing trend.3. The average caloric value and standing crop of energy of phytoplankton were 11.61 KJ.g-1 DM and 139.82 KJ.m-2, respectively: their seasonal change laws were somewhat different. The energy conversion efficiency of total radiation by phytoplankton averaged 0. 68%.
