Haijun Ren Liang Wu Predrag Neskovic Leon N. Cooper Approximating a non-homogeneous HMM with Dynamic Spatial Dirichlet Process. 1-4 2008 ICPR http://dx.doi.org/10.1109/ICPR.2008.4761919 conf/icpr/2008 db/conf/icpr/icpr2008.html#RenWNC08