1. University of Peloponnese,Department of Informatics and Telecommunications,Tripolis,Greece
2. University of Ioannina,Department of Physics, Electronics-Telecoms and Appl. Lab (ETA-Lab),Ioannina,Greece
3. University of Ioannina,Department of Physics,Ioannina,Greece,GR-45110
4. Agricultural University of Athens,Department of Natural Resources Management and Agricultural Engineering,Athens,Greece