Algae (Label Ranking data)

This Label Ranking dataset is adapted from the original version which is stored in the UCI Machine Learning Repository: http://archive.ics.uci.edu/ml/datasets/Coil+1999+Competition+Data This data comes from a water quality study where samples were taken from sites on different European rivers of a period of approximately one year. These samples were analyzed for various chemical substances including: nitrogen in the form of nitrates, nitrites and ammonia, phosphate, pH, oxygen, chloride. For each sample, the frequencies of 7 types of algae were also measured. We considered the algae concentrations as preference relations by ordering them from larger to smaller concentrations. Those with 0 frequency are placed in last position and equal frequencies are represented with ties. Missing values in the independent variables were set to 0 (zero). RData file contains 2 matrices: x - a matrix of independent variables y - a matrix of rankings of the 7 algae types本标签排序（Label Ranking）数据集改编自存储于UCI机器学习库（UCI Machine Learning Repository）的原始版本，原始数据集的访问链接为：http://archive.ics.uci.edu/ml/datasets/Coil+1999+Competition+Data。该数据集源自一项水质研究，研究人员在为期约一年的周期内，从欧洲多条河流的多个采样点位采集了水样样本。研究人员对这些样本开展了多类化学物质检测，检测指标包括以硝酸盐、亚硝酸盐及氨形态存在的氮，磷酸盐、pH值、溶解氧以及氯化物。针对每个样本，研究人员同时测定了7种藻类的出现频率。我们将藻类浓度按从高到低的顺序进行排列，以此将浓度值转化为偏好关系。出现频率为0的藻类将被置于排序末尾，频率相同的藻类则以并列关系表示。自变量中的缺失值均被赋值为0。该数据集的RData文件包含两个矩阵：x为自变量矩阵，y为7种藻类的排序矩阵。