4 research outputs found
Immediate event-aware model and algortithm of a general scheduler
A stochastic scheduling problem is investigated in this work that considers
workpieces to be manufactured according to individual recipes containing
manufacturing steps performed by workstations as resources. Unexpected
stochastic breakdown of a workstation or the faulty termination of a recipe,
when a manufacturing failure renders the workpiece out of specifications,
forms the set of immediate events. A model and an algorithm are proposed
as the basis of a scheduler, which takes into account the possible
immediate events, estimates their probability and suggests resource
allocations which provide the best overall work-flow even when an
immediate event happens. This model includes the possibility of handling
alternative resources that can substitute each other in case of an
immediate event, like sudden technical failure of a resource. Immediate
events are not exactly predictable; however, based on previous
experiences, their probabilities can be estimated. Our model uses the
properties of the resources (including how they can substitute other types
of resources) and the required sequence of them during the workflow (i.e.
the recipes). The proposed scheduling algorithm constructs a solution
workflow that reacts in the best way (in average) even for an unexpected
event. The proposed model and scheduling algorithm is illustrated on two
industrial case studies