Xiao Huang Juyang Weng Motivational System for Human-Robot Interaction. 17-27 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3058&spage=17 2004 conf/eccv/2004hci ECCV Workshop on HCI db/conf/eccv/eccv2004hci.html#HuangW04