Jezekiel Ben-Arie Zhiqian Wang Purvin Pandit ShyamSundar Rajaram Human Activity Recognition Using Multidimensional Indexing. 1091-1104 2002 24 IEEE Trans. Pattern Anal. Mach. Intell. 8 http://computer.org/tpami/tp2002/i1091abs.htm db/journals/pami/pami24.html#Ben-ArieWPR02