MultiMedia modeling 25th International Conference, MMM 2019, Thessaloniki, Greece, January 8–11, 2019, proceedings, part II - Kompatsiaris, Yiannis; Huet, Benoit; Mezaris, Vasileios; Gurrin, Cathal; Cheng, Wen-Huang; Vrochidis, Stefanos (Lecture notes in computer science, 2019)