1. Dept. of Civil and Environmental Engineering, 205 North Mathews Ave., Univ. of Illinois, Urbana-Champaign, IL 61801; and Computer Scientist, Applied Research Associates, Inc., 505 W. University Ave., Champaign, IL 61820; formerly, PhD student, Construction Management Information Technology Group.and
2. Assistant Professor, Computer Science Dept., Univ. of Chile, Av. Blanco Encalada 2120, 3er. Piso, Santiago, Chile.
3. Associate Professor of Construction Management and Information Technology, Dept. of Civil and Environmental Engineering, Newmark Civil Engineering Laboratory, Room 3129, MC-250, 205 North Mathews Ave., Univ. of Illinois, Urbana-Champaign, IL 61801.
4. Professor, Computer Science Dept., Catholic Univ. of Chile, Vicuna Mackenna 4860, Macul, Santiago, Chile.