1. Researcher, School of Electrical and Computer Engineering, National Technical Univ. of Athens, 9 Iroon Politechniou St., Zografou 157 80, Athens, Greece.
2. Assistant Professor, Dept. of Electrical Educators, A.S.PE.T.E.—School of Pedagogical and Technological Education, N. Ηeraklion 141 21, Athens, Greece (corresponding author).
3. Senior Researcher, School of Electrical and Computer Engineering, National Technical Univ. of Athens, 9 Iroon Politechniou St., Zografou 157 80, Athens, Greece.
4. Associate Professor, Technological Educational Institute of Kalamata, Antikalamos 24 100, Kalamata, Greece.