1. Department of Industrial, Manufacturing and Systems Engineering, University of Texas at El Paso, 500 W University Avenue, Engineering Building, A-244, El Paso, TX 79968 e-mail:
2. IBM Research, Singapore, 10 Marina Boulevard, Marina Bay Financial Centre Tower 2, Singapore 18983, Singapore e-mail:
3. Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, 48-121G Eng IV, Los Angeles, CA 90095 e-mail: