System Innovation in a Post-Pandemic World contains the papers presented at the IEEE 7th International Conference on Applied System Innovation (ICASI 2021, Alishan, Taiwan, September 24-25, 2021). The conference received more than 200 submitted papers from 11 different countries, whereby roughly one third of these papers was selected by the committees and invited to present at ICASI 2021. The book provides an integrated communication platform for researchers from a wide range of disciplines including information technology, communication science, applied mathematics, computer science, advanced material science, and engineering. Hopefully, interdisciplinary collaborations between science and engineering technologists in the domains of academia and industry will be enhanced via this unique international network.