1. Department of Industrial Management & Technology, University of Piraeus, 107 Deligiorgi St, Piraeus 185 34, Greece
2. School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou St, Zografou 15780, Greece
3. Department of Business Administration, Technological Educational Institution of Peiraius, 250 Thivon and Petrou Ralli Av., 122 44 Egaleo, Greece
4. Department of Computer Science & Engineering, European University Cyprus, Cyprus