Ioannis Papadakis1, Fragoulis D Krokos2,3, Christos Trapalis4. 1. School of Science and Technology, Hellenic Open University, Patras, GR 263 35, Greece. papadakis@iqc.gr. 2. School of Science and Technology, Hellenic Open University, Patras, GR 263 35, Greece. 3. Hellenic Organization for Standardization, National Quality Infrastructure System, Peristeri, GR 121 33, Greece. 4. Hellenic Accreditation System, National Quality Infrastructure System, Kallithea, GR 176 76, Greece.