SHMUC Use Case A1

An Over-Long Shower: (Ver. 1.0)


SHMUC prototype  >  A_Duration_Use_Cases  >  A1_Over_Long_Shower


To detect an activity with an unusually long duration
Actors Mary, the Smart Home, Debbie

Initial State


Mary was at home alone.



Mary woke up at 0800 as usual, and prepared to take a shower. She began her shower at 0810 and at 0840 she was still taking a shower, since the motion sensor in the shower room and the shower tap were on at that time. The system checked her profile and found that she never took showers longer than 20 minutes, and that during winter they were generally even shorter.

Norm Shower duration is normally between 10 and 20 minutes


An alert message was sent to Debbie, who called a carer. The carer discovered Mary confused and cold in the shower, having forgotten what she was doing.

System Design Implications

When an activity takes longer than it should, it may put the smart home inhabitant at risk. In this case, the activity took 30 minutes, 10 minutes longer than usual. 

We might pose the following questions.

  1. When does a shower become longer than usual? 1 minute over the average? 5? 10? OR is the amount relative 1%? 5%? 10%? Perhaps a more statistical approach is appropriate - more than 1 standard deviation from the mean.
  2. A longer-than-usual shower is interesting behaviour, but should it be treated as a problem?