1. Department of Civil & Environmental Engineering, Rice University, Houston, TX, USA and Department of Civil & Environmental Engineering, Department of Industrial Engineering Universidad de los Andes Bogotá Colombia
2. Department of Mechanical Engineering University of Melbourne Melbourne VIC Australia
3. Department of Civil & Environmental Engineering Rice University Houston TX USA
4. William E. Boeing Department of Aeronautics and Astronautics University of Washington Seattle WA USA
5. Complexity Sciences Center, Department of Mechanical and Aerospace Engineering, and Department of Computer Science University of California Davis, CA, USA and Santa Fe Institute Santa Fe NM 87501 USA