U2R: Underwater Ultrasonic Reflection Wave Dataset Toward Pose-Invariant Material Recognition. - Mayuka Kono; Yutaro Hirao; Monica Perusquía-Hernández; Naoya Isoyama; Hideaki Uchiyama; Nobuchika Sakata; Jun Takamatsu; Kiyoshi Kiyokawa (ICASSP, 2024)