1. Department of Decision Sciences, George Washington University, Washington, District of Columbia, 20052;
2. Department of Industrial and Systems Engineering, University of Minnesota, Minneapolis, Minnesota 55455;
3. Department of Statistics and Operations Research, Department of Genetics, Department of Biostatistics, Carolina Center for Genome Sciences, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27599;
4. The Daniel J. Epstein Department of Industrial and Systems Engineering, University of Southern California, Los Angeles, California 90007