1. A method of identifying an activity of an object, comprising: identifying each elemental motion of a sequence of elemental motions of a device attached to the object; and identifying the activity of the object, comprising matching the sequence of identified elemental motions of the device with a library of stored sequences of elemental motions, wherein each stored sequence of elemental motions corresponds with an activity; and making a telephone call through a telephone base station to request help if a dangerous condition is detected, and wherein sequences of human motions are classified into groups of similar postures represented by model-states with a posture model depicting inter-relationships among model-states.