1. Advanced Technologies Institute, 10 Dinu Vintilă, 021102 Bucharest, Romania
2. Faculty of Computer Systems and Cybersecurity, Military Technical Academy, 39-49 George Coşbuc, 050141 Bucharest, Romania
3. Simion Stoilow Institute of Mathematics of the Romanian Academy, 21 Calea Grivitei, 010702 Bucharest, Romania