Preface Ange Nzihou, Ramaraj Boopathy, Mohamed Nasef, Suzana Yusup, Daniel C.W. Tsang, Nurul Aini Amran and Bawadi Abdullah E3S Web Conf., 287 (2021) 00001 Published online: 06 July 2021 DOI: 10.1051/e3sconf/202128700001