Description

Isolation Forest (or iForest) is a well-known technique for anomaly detection. It is, however, a bulky approach that assumes the luxury of large storage space and is also ineffective with dynamic streaming data so common nowadays in varied application domains. In this work, we present the Preprocessed Isolation Forest (PiForest) approach for anomaly detection that works well in resource constrained environments and is also effective on streaming data. PiForest is largely based on the iForest algorithm and to effectively handle the streaming data includes a pre-processing stage. In the pre-processing stage, Principal Component Analysis (PCA) is first harnessed to significantly reduce the dimension and bulk of the data. Subsequently, the streaming characteristic of the data is handled through a sliding window mechanism that creates sequential blocks of data for systematic processing. PiForest is able to identify anomalies as effectively asiForest and other state-of-theart anomaly detection techniques but has substantially low storage and prediction complexity.