Preface The COVID-19 pandemic has made 2020 an extraordinarily tough year, with the entire world fighting against the COVID-19, which is seriously affecting economic development, international academic exchanges, and even threatening people's health safe. Governments around the world took effective measures to stop the spread of COVID-19 by forcing people to wear masks, keeping social distance, and even conducting nucleic acid tests. All of these measures have had positive results, however, the severity of the epidemic seems to be greater than we could have imagined. Until the end of 2020, the spread of COVID-19 epidemic has not been effectively curbed. Academic communication and research results sharing are the main purposes of academic conferences. However, with regard to the health and safety of participants, we had to hold the ISERSS-20 via video mode, considering that the COVID-19 epidemic will not be eliminated in a short time. With the help of an online meeting platform and network technology, ISERSS-20 was praised by the participants with outstanding results. However, the online conference also comes with some drawbacks, such as the difficulty in coordinating participants staying in different time zones, occasionally unstable network signals, and the unfamiliarity of some senior participants with the functions of the meeting platform.

ISERSS was sponsored by INTI International University & Colleges and Tunku Abdul Rahman University in video presentation on December 28, 2020. The successful launching of the two sessions of ISERSS in the past has attracted more and more international scholars to submit papers and participate in the conference. This time, 235 papers from scholars from over 10 countries and regions are submitted, including USA, Russia, Ukraine, Taiwan, Hong Kong, Malaysia, and China's mainland. After rigorous peer-review, 97 full-papers were accepted and the authors were invited to deliver video presentations to share their research results. The duration for video presentations is about 15 minutes, and all videos have been uploaded to the webserver and will be available for a long time. All participants can watch the presentation videos at any time and communicate with the authors via email. The video conferencing is an innovative attempt of academic conference in the context of COVID-19 epidemic. Many participants were optimistic about the conference, for it not only realized the communication and sharing of research results, but also overcame the geographical and time constraints, and more importantly, ensured the safety of the participants.

Finally, we are grateful for the conference committees who have made great efforts in organizing the conference, for the reviewers, and for those scholars that submitted their manuscripts to ISERSS-20 and actively participated in it.

We are looking forward to your attention and participation in the 4th ISERSS Conference in 2021.

Conference Committee and Editors