Estimating a User's Conversational Engagement Based on Head Pose Information. - Ryota Ooko; Ryo Ishii; Yukiko I. Nakano (IVA, 2011)

Effectiveness of Gaze-Based Engagement Estimation in Conversational Agents. - Ryo Ishii; Ryota Ooko; Yukiko I. Nakano; Tokoaki Nishida (Eye Gaze in Intelligent User Interfaces, 2013)