When a mechanic that is servicing a machine becomes free, he has to service a machine
in need of service and that is not being serviced, or replace a specific mechanic in order to
increase the manpower utilisation and at the same time, maximise machine availability.
The MBS consists of a dynamic work allocation mechanism for assigning a mechanic to a
down machine, and a pre-emption mechanism for replacing a mechanic that is already
servicing a machine, with each mechanism governed by distinct rules, which are introduced
next.