1. A non-transient computer-readable medium or media comprising one or more sequences of instructions which, when executed by one or more processors, causes steps for recognizing a sequence of actions comprising: segmenting input sensor data into time frames; generating a feature for each time frame; for a time frame, selecting an action associated with a maximized value of an objective function that comprises a first set of feature-dependent models for intra-action transitions and a second set of feature-dependent models for inter-action transitions; wherein the feature-dependent models are based a on linear dynamic system models; and wherein the objective function models a hidden state at a current time frame as being directly dependent upon a hidden state for a sequence of one or more time frames prior to the current time frame, an estimated action for the sequence of one or more time frames prior to the current time frame, and an estimated action of the current time frame.