Smart Cities, Green Technologies, and Intelligent Transport Systems : 9th International Conference, SMARTGREENS 2020, and 6th International Conference, VEHITS 2020, Prague, Czech Republic, May 2-4, 2020, Revised Selected Papers - Klein, Cornel; Berns, Karsten; Gusikhin, Oleg; Helfert, Markus (Springer, 2021)