SHMUC prototype > A_Duration_Use_Cases
<Insert general description of the use cases in this class>
A1 An Over-Long Shower
A2 A Justifiably Short Shower
A3 A Long Nap
It could be thought that once a behaviour has been correctly identified, recognising when the duration of that behaviour is too long or too short is a simple task. However, the anomaly needs to be detected while the activity is still happening, meaning that not all of the cues to the behaviour may have been seen. If we wait until the activity finishes, a dangerous situation may have occurred before the alert. Additionally, there are many contextual factors that affect the duration of an activity; Fig. 2 highlights some potential factors for the showering behaviours. Identifying, representing and accounting for them in the reasoning process is non-trivial. Finally, it is not clear how much too long or short the duration of a behaviour should be before it is considered abnormal. This obviously depends upon the statistical variance in the normal duration of the activity, and also what the behaviour is – ten minutes too long in the oven is less serious than ten minutes too long in the microwave. This is a very difficult research problem that has been largely ignored so far. We believe that an ontology or similar representation of knowledge will be required.