“…Temporal collaborative filtering with matrix [4,7] and tensor factorization techniques [3] can generate accurate recommendation, since they can capture the drifts in the rating behavior and the changes of user preference over time in a collaborative-filtering fashion. However, users may repeatedly interact with items over time in several applications [2]; for instance, visiting the same web sites, buying retail items from Amazon or implicitly interacting, such as artist listenings on last.fm or movie viewing from a specific genre on MovieLens. To account also for the fact that users' side information, such as demographics, can improve the recommendation accuracy [5], we present a basic CTF model and its variant W-CTF, where the diversity of Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage, and that copies bear this notice and the full citation on the first page.…”