Weiyao Lin Ming-Ting Sun Radha Poovendran Zhengyou Zhang Human activity recognition for video surveillance. 2737-2740 2008 ISCAS http://dx.doi.org/10.1109/ISCAS.2008.4542023 conf/iscas/2008 db/conf/iscas/iscas2008.html#LinSPZ08