1. Full professor, Dept. of Computer Science, Mathematics, Electronics, and Transportation, Mediterranea Univ. of Reggio Calabria, Feo di Vito, 89060 Reggio Calabria, Italy.
2. Assistant Professor, Dept. of Civil Engineering, Tor Vergata Univ. of Rome, Via del Politecnico 1, 00133 Rome, Italy (corresponding author).