[1] Technol Educ Inst Western Greece, Dept Informat, GR-30300 Naupaktos, Greece
[2] Technol Educ Inst Western Greece, Fac Econ & Management, Dept Business Adm, GR-26334 Patras, Greece
[3] King Saud Univ, Coll Sci, Dept Math, Riyadh 11451, Saudi Arabia
[4] Univ Peloponnese, Fac Sci & Technol, Comp Sci Lab, Dept Comp Sci & Technol, GR-22100 Tripolis, Greece