INDUSTRIAL ROBOT-AN INTERNATIONAL JOURNAL, vol. 35, no. 5, page. 435 - 448, 2008-01
ETRI JOURNAL, vol. 29, no. 2, page. 189 - 200, 2007-04
INDUSTRIAL ROBOT-AN INTERNATIONAL JOURNAL, vol. 35, no. 3, page. 259 - 265, 2008-05