A construction of the progressive (3, n)-threshold visual cryptography using a BIBD and analysis of its optimality. - Koutaro Okada; Hiroki Koga (ITW, 2017)

A Construction of the (4, n)-Threshold Visual Cryptography Scheme Using a 3-Design. - Koutaro Okada; Hiroki Koga (ISITA, 2018)

Analysis of Participants' Synchronization Behaviors and Big Five Personalities in Dyadic Conversation. - Koutaro Okada; Yuya Okadome (HCI (56), 2024)