1. Mem. ASME H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, GA 30332 e-mail:
2. H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, GA 30332 e-mail:
3. The Boeing Company, 900 N Sepulveda Boulevard, El Segundo, CA 90245 e-mail:
4. ASME Fellow H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, GA 30332 e-mail: