1. Researcher and Ph.D. Student, Water Distribution and Sewerage Systems Research Center, Universidad de los Andes, Bogotá, Colombia.
2. Professor and Department Head, Dept. of Civil and Architectural Engineering and Mechanics, College of Engineering, Univ. of Arizona, Tucson, AZ.
3. Professor, Dept. of Civil and Environmental Engineering, Water Distribution and Sewerage Systems Research Center, Universidad de los Andes, Bogotá, Colombia.