Architecting and designing : Business Process Analysis (BPA) : Simulation of Process Models : Simulating resource utilization : Shifts
  
Shifts
When Simulating resource utilization, availability of both processes (all types) and resources are controlled by shifts. You specify that a Role performs work during a Shift in the Resource availability definition. Shifts represent combinations of work and rest time. When a shift profile is in a rest period no objects will be generated at an event, processed and event a result receiving an object.
Automated processes can use a shift to represent their availability but will not require a resource allocation. Manual processes will also require a resource allocation, which also associated with a shift.
Shifts are made up of collections of Single periods. A single period contains a single work and rest duration. An “overtime” duration is provided to specify an additional work duration to reflect overtime working (currently there is no facility to associate a different costing to this category).
A shift can either be designated as a single shift or a collection of single shifts called Sub shifts.
The following should apply when creating Shifts:
By default if no shift is allocated to any type of process then that process will always be available.
Resources always require a shift allocation.
The shift allocated to the process will always override the resource availability even if the resource is on shift.
Rest periods applied to holds will not count towards the time the object has been in the hold.
Object arrival profiles will start when an event is “on shift”, for example, a profile of two objects every hour will produce two objects after one hour of on shift time.
Depending on the fidelity of how you want to simulate workers performing, you could set a Working Duration as: “1 day”, “7 hours and a 17 hour Rest Duration”, and so on.
See also
Simulating resource utilization