1. Department of Management Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China
2. Department of Industrial Engineering, Pusan National University, Busan, Korea
3. Department of Management Science and Engineering, Nanjing University of Science and Technology, Nanjing, China
4. Department of Management Science and Statistics, The University of Texas at San Antonio, San Antonio, TX 78249, USA