Cortex uses an innovative process for house, floor and room objects giving
them the property of presence
It can then determine which are occupied and track movement between
them
It can also calculate the number of people in the property and their location
This presence property can then be used to trigger events or control actions
  so that they are only initiated on occupied rooms
Use of presence rather than motion greatly enhances the overall automation
   
 (click on thumbnails to enlarge)