Research on Quantitative Evaluation of Post Safety Competency of Port Operators Hang Jin, Guodong Meng, Yanhua Hu, Pengyu Jia, Wenxin Jiang and Shuifen Zhan E3S Web Conf., 257 (2021) 02087 Published online: 12 May 2021 DOI: 10.1051/e3sconf/202125702087