9 A two-level mixture linear dynamic system model, with frame-level switching parameters in the obser10 vation equation and with segment-level switching parameters in the target-directed state equation, is de11 veloped and evaluated. The main contributions of this work are: (1) the new framework for dealing with 12 mixed-level switching in the dynamic system and (2) the novel use of piecewise linear functions, enabled by
Jeff Z. Ma, Li Deng