Design, User Experience, and Usability. Design Philosophy and Theory 8th International Conference, DUXU 2019, Held as Part of the 21st HCI International Conference, HCII 2019, Orlando, FL, USA, July 26-31, 2019, Proceedings, Part I - Marcus, Aaron; Marcus, Aaron; Wang, Wentao; Wang, Wentao (Springer International Publishing : Imprint: Springer, 2019)