1. Assistant Professor, Dept. of Architecture, Design and Urban Planning, Univ. of Sassari, 07041 Alghero, Italy.
2. Senior Research Scientist, Dept. of Physics, Northeastern Univ., Boston, MA 02115.
3. Associate Professor, Dept. of Civil and Environmental Engineering, Northeastern Univ., 400 Snell Engineering Center, Boston, MA 02115 (corresponding author).