On Detecting Clustered Anomalies Using SCiForest

Detecting local clustered anomalies is an intricate problem for many existing anomaly detection methods. Distance-based and density-based methods are inherently restricted by their basic assumptions--anomalies are either far from normal points or being sparse. Clustered anomalies are able to avoid detection since they defy these assumptions by being dense and, in many cases, in close proximity to normal instances. In this paper, without using any density or distance measure, we propose a new method called SCiForest to detect clustered anomalies. SCiForest separates clustered anomalies from normal points effectively even when clustered anomalies are very close to normal points. It maintains the ability of existing methods to detect scattered anomalies, and it has superior time and space complexities against existing distance-based and density-based methods.

• Type: Journal
• Year: 2010
• Where: PKDD
• Authors: Fei Tony Liu, Kai Ming Ting, Zhi-Hua Zhou
• Keywords: Data Mining, Density-based Methods, Local Clustered Anomalies, Normal Points, PKDD 2010