Randomized processes to create diverse models for One-class classifier ensembles

One-class classification (OCC) is a machine learning technique employed in scenarios involving imbalanced data, limited labeled data, or the need to detect anomalies or novel patterns. One-Class Classification by Ensembles of Regression (OCCER) models have shown excellent performance for OCC problems. In this paper, we study whether the combinations of ensemble methods such as random subspace and random projection with OCCER can be used to improve the performance of OCCER. Our main objective is to explore the impact of diversity creation methods, including bagging, random subspace, and random projections, on enhancing the performance of the OCC ensemble method. Additionally, we investigate the feasibility of applying the OCCER ensemble method to a novel low-dimensional space generated by autoencoders, all while maintaining high prediction accuracy. The experimental results over 37 datasets demonstrate that the creation of diverse OCCER models using random subspace and random projection substantially improves the performance of the OCCER. The diversity creation method, Random subspaces, outperforms other diversity creation methods.