1. A method of controlling a device without touching it, comprising the steps of: storing a dynamic motion model including gesture information collected over time, the stored model including information describing a particular dynamic gesture to be recognized in the form {dot over (x)}=f(x, θ) where {dot over (x)} is a vector describing the position and velocity components of the gesture and θ is a tunable parameter; sensing a human motion to be recognized; extracting position and velocity components of the sensed motion; determining if the motion is a recognizable gesture based upon the extracted position and velocity components and tunable parameters of the sensed motion; and if the motion represents a recognizable gesture, generating a command to control a device in accordance with the recognized gesture.