1. Full Professor, Hydraulic Sector, Dept. of Land Engineering, Univ. of Cagliari, via Marengo 2, 09123 Cagliari, Italy.
2. Adjunct Professor, Hydraulic Sector, Dept. of Land Engineering, Univ. of Cagliari, via Marengo 2, 09123 Cagliari, Italy (corresponding author).