datepublished: 2015subjectTerm: I. MATHEMATICS AND COMPUTER SCIENCE_or_III. ENGINEERING AND TECHNOLOGY_or_II. NATURAL SCIENCES AND AGRICULTURAL SCIENCESauthor: Fountzoula, Christina_or_Papaioannou, Angelos_or_Spyropoulos, Vasileios_or_Σπυρόπουλος, Βασίλειος__el