Measuring and Integrating Facial Expressions and Head Pose as Indicators of Engagement and Affect in Tutoring Systems. - Hao Yu 014; Ankit Gupta 016; Will Lee 002; Ivon Arroyo; Margrit Betke; Danielle Allesio; Tom Murray 001; John J. Magee; Beverly P. Woolf (HCI (32), 2021)