Advances in Network-Based Information Systems The 21st International Conference on Network-Based Information Systems (NBiS-2018) - Barolli, Leonard; Barolli, Leonard; Kryvinska, Natalia; Kryvinska, Natalia; Enokido, Tomoya; Enokido, Tomoya; Takizawa, Makoto; Takizawa, Makoto (Springer International Publishing : Imprint: Springer, 2019)