1. Graduate School of Engineering, Fukuoka Institute of Technology (FIT), Japan
2. Department of Information and Computer Engineering, Okayama University of Science (OUS), Japan
3. Department of Information and Communication Engineering, Fukuoka Institute of Technology (FIT), Japan. E-mail: barolli@fit.ac.jp
4. Department of Information Technology, Aleksander Moisiu University of Durres, L.1, Rruga e Currilave, Durres, Albania