1. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
2. Laboratory of Computational Social Science, Networks Department, IMT Lucca Institute for Advanced Studies, 55100 Lucca, Italy.
3. Institute for Complex Systems of the National Research Council, Physics Department, University of Rome “Sapienza,” Piazzale Moro 5, 00185 Rome, Italy.
4. Center for Complex Engineering Systems at King Abdulaziz City for Science and Technology and MIT, Cambridge, MA 02139, USA.