1. ELEDIA@AUTH, School of Physics, Aristotle University of Thessaloniki,Thessaloniki,Greece,54124
2. University of Western Macedonia,Department of Informatics and Telecommunications Engineering,Kozani,Greece
3. University of Macedonia,Department of Applied Informatics,Thessaloniki,Greece,54124
4. School of Electrical and Computer Engineering, Aristotle University of Thessaloniki,Thessaloniki,Greece,54124