The paper "POLARIS: Probabilistic and Ontological Activity Recognition in Smart-Homes," by G. Civitarese, T. Sztyler, D. Riboni, C. Bettini and H. Stuckenschmidt has appeared in the January 2021 issue of IEEE Transactions on Knowledge and Data Engineering. Doi: 10.1109/TKDE.2019.2930050.