participant Dworkin, Ian Instructor 2018 Dworkin, Ian Instructor 2019 Stone, Jonathon Instructor 2019 Xu, Jianping Instructor 2018 Xu, Jianping Instructor 2019 Xu, Jianping Instructor 2020 Xu, Jianping Instructor 2020 Zhu, Xu-dong Instructor 2018