Jianfeng Xu Toshihiko Yamasaki Kiyoharu Aizawa 472-479 2006 conf/3dpvt/2006 3DPVT http://doi.ieeecomputersociety.org/10.1109/3DPVT.2006.95 db/conf/3dpvt/3dpvt2006.html#XuYA06