1. International Hellenic University,Physics Department,Kavala,Greece
2. Aristotle University of Thessaloniki,Department of Mathematics,Thessaloniki,Greece
3. Universitat de les Illes Balears,Industrial Engineering Department,Palma,Spain
4. School of Science and Technology, International Hellenic University,Thessaloniki,Greece
5. Institute of Circuits and Systems, Technical University Dresden,Dresden,Germany