Extended Histogram-based Outlier Score (EHBOS)
This work addresses the problem of anomaly detection in datasets with complex feature dependencies, which is significant for data analysts and researchers working with diverse datasets.
The authors tackled the limitation of the Histogram-Based Outlier Score (HBOS) method in detecting anomalies in datasets with feature interactions, and the proposed Extended Histogram-Based Outlier Score (EHBOS) achieved notable improvements in ROC AUC on several datasets. EHBOS outperformed HBOS, particularly on datasets where feature interactions are critical.
Histogram-Based Outlier Score (HBOS) is a widely used outlier or anomaly detection method known for its computational efficiency and simplicity. However, its assumption of feature independence limits its ability to detect anomalies in datasets where interactions between features are critical. In this paper, we propose the Extended Histogram-Based Outlier Score (EHBOS), which enhances HBOS by incorporating two-dimensional histograms to capture dependencies between feature pairs. This extension allows EHBOS to identify contextual and dependency-driven anomalies that HBOS fails to detect. We evaluate EHBOS on 17 benchmark datasets, demonstrating its effectiveness and robustness across diverse anomaly detection scenarios. EHBOS outperforms HBOS on several datasets, particularly those where feature interactions are critical in defining the anomaly structure, achieving notable improvements in ROC AUC. These results highlight that EHBOS can be a valuable extension to HBOS, with the ability to model complex feature dependencies. EHBOS offers a powerful new tool for anomaly detection, particularly in datasets where contextual or relational anomalies play a significant role.