Knowledge Science, Engineering and Management 12th International Conference, KSEM 2019, Athens, Greece, August 28-30, 2019, Proceedings, Part II - Douligeris, Christos; Douligeris, Christos; Karagiannis, Dimitris; Karagiannis, Dimitris; Apostolou, Dimitris; Apostolou, Dimitris (Springer International Publishing : Imprint: Springer, 2019)