©2023 IEEE DOI 10.1109/ASE56229.2023.00094 ABSTRACT Unsupervised learning systems using clustering have gained significant attention for numerous applications due to their unique ability to discover patterns and structures in large unlabeled datasets. However, their effectiveness highly depends on their configuration, which requires domain-specific expertise and often involves numerous manual trials. Specifically, selecting appropriate algorithms and hyperparameters adds to the complexity of the configuration process. In this paper, we propose, apply, and assess an automated approach (AutoConf) for configuring unsupervised learning systems using clustering, leveraging metamorphic testing and Bayesian optimization. Metamorphic testing is utilized to verify the configurations of unsupervised learning systems by applying a series of input transformations. We use Bayesian optimization guided by metamorphic-testing output to automatically identify the optimal configuration. The approach aims to streamline the configuration process and enhance the effectiveness of unsupervised learning systems. It has been evaluated through experiments on six datasets from three domains for anomaly detection. The evaluation results show that our approach can find configurations outperforming the baseline approaches as they achieved a recall of 0.89 and a precision of 0.84 (on average). AUTHORS Lwin Khin Shar∗, Arda Goknil†, Erik Johannes Husom‡, Sagar Sen°◊, Yan Naing Tun¢“ and Kisub Kim School of Computing and Information Systems, Singapore Management University and SINTEF Digital, Norway Email: ∗lkshar@smu.edu.sg, †arda.goknil@sintef.no, ‡erik.johannes.husom@sintef.no, °◊sagar.sen@sintef.no, ¢“yannaingtun@smu.edu.sg, kisubkim@smu.edu.sg