基于孤立森林采样策略的企业异常用水模式检测

Detecting Abnormal Water Consumption Pattern of Enterprise Based on Isolation Forest Sampling

为解决企业异常用水模式检测过程中的低频短时间序列数据和不平衡分类问题,提出了一种基于孤立森林采样策略的二分类预测方法。首先构造用水波动性特征和统计性特征,利用孤立森林算法计算多数类中样本点的“孤立”程度以衡量每个样本的“代表性”,再按样本“代表性”排序,对“代表性”高的样本优先进行采样;然后将抽取出的样本与少数类合并,构成较平衡的训练样本集;最后利用较平衡的数据集训练XGBoost分类器并进行预测。在某市的7604家企业13个月的用水量数据集上,该方法对企业异常用水模式的预测结果AUC和查全率可达到0.927和0.891,比基于随机欠采样的XGBoost方法的0.885和0.733分别提升了4.7%和21.6%。

To solve the low-frequency short-sequence data and unbalanced classification problem in detecting the abnormal water consumption pattern of enterprises,this paper proposes a two-class prediction method based on Isolation Forest sampling.Firstly,the volatility and statistical features of water consumption are constructed.The Isolated Forest algorithm is used to calculate the degree of isolation of samples in the large class to measure the representation of each sample,and the samples are extracted according to their representation.Then the extracted samples are merged with the small class to form a balanced training dataset.Finally,the XGBoost classifier is trained with the balanced dataset and predicting the abnormal pattern.On the dataset of 7,604 enterprises’13-month water consumption in a city,the AUC and recall ratio of the method proposed by this paper can reach 0.927 and 0.891,and those of XGBoost method based on random under sampling are 0.855 and 0.733,which are improved by 4.7%and 21.6%respectively.