1. Aristotle University of Thessaloniki,School of Physics,Thessaloniki,Greece
2. Yuriy Fedkovych Chernivtsi National University,Department of Radio Engineering and Information Security,Chernivtsi,Ukraine
3. University of Western Macedonia,Department of Electrical & Computer Engineering,Kozani,Greece
4. University of Macedonia Aristotle,Department of Applied Informatics,Thessaloniki,Greece