Over the last few decades, various methods have been proposed for estimating prediction intervals in regression settings, including Bayesian methods, ensemble direct interval estimation and conformal methods. An important issue is calibration of these methods: generated should a predefined coverage level, without being overly conservative. In this work, we review above four classes from concept...

Internal cluster validity measures (such as the Calinski-Harabasz, Dunn, or Davies-Bouldin indices) are frequently used for selecting appropriate number of partitions a dataset should be split into. In this paper we consider what happens if treat such indices objective functions in unsupervised learning activities. Is optimal grouping with regards to, say, Silhouette index really meaningful? It...