Hideaki Kanai Goushi Tsuruma Toyohisa Nakada Susumu Kunifuji Notification of dangerous situation for elderly people using visual cues. 345-348 2008 IUI http://doi.acm.org/10.1145/1378773.1378826 conf/iui/2008 db/conf/iui/iui2008.html#KanaiTNK08