State magic: state estimation for Android smartphone. - Tatsuhito Hasegawa; Makoto Koshino; Satoshi Hirahashi; Haruhiko Kimura (UbiComp/ISWC Adjunct, 2015)

Determining a smartphone's placement by material detection using harmonics produced in sound echoes. - Tatsuhito Hasegawa; Satoshi Hirahashi; Makoto Koshino (MobiQuitous, 2016)

Determining Smartphone's Placement Through Material Detection, Using Multiple Features Produced in Sound Echoes. - Tatsuhito Hasegawa; Satoshi Hirahashi; Makoto Koshino (IEEE Access, 2017)