1. School of Maritime Economics and Management, Dalian Maritime University, 116026 Dalian, PR China
2. Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
3. Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576; and Institute for Operations Research and Analytics, National University of Singapore, Singapore 119077
4. School of Management, Huazhong University of Science and Technology, 430074 Wuhan, PR China