Abstract
This Chapter introduces a formal language used to model complex relationships between detectable human activities, events and robot behaviours that are to be detected by robots in streams of sensory data. The Ubiquitous Robotics paradigm is adopted in order to show how distributed sources of information can be easily integrated to assess the current context. Specific emphasis is devoted to the use of context assessment techniques to enforce the adaptation of robot behaviours to human activity. The model is described both theoretically and with a thorough example.