1. Antai College of Economics & Management, Shanghai Jiao Tong Univ., No. 1954, Huashan Rd., Shanghai 200000, China; College of Economics and Management, Nanjing Univ. of Aeronautics and Astronautics, Nanjing 211106, China; NARI Group Corporation/State Grid Electric Power Research Institute, Nanjing 211106, China (corresponding author).
2. Professor, College of Economics and Management, Nanjing Univ. of Aeronautics and Astronautics, Nanjing 211106, China.