I. Introduction
Lifelogging (also known as Quantified self [1]), which is a historical dataset of user activities (and behaviors), has been regarded as an important information for understanding their personal contexts (e.g., interests and patterns). Especially, with various smart devices and wearable devices, it has been much easier for users to record their lifeloggings. Given a particular domain, lifelogging has been studied for various applications, e.g., storification [2] and MyMovieHistory [3].