Timing of the Schedule


Discrete-event models keep track of individual entities, so that the state of the model changes only when events occur. We chose to follow a discrete event format because it offers a flexible and natural way to model the system. For modelling purposes there are three event types held within an array, the table below outlines the event types:






Farm arrival

Both truck and van arrivals at the farms


Farm departure

Both truck and van departures from a farm


Plant event

When trucks arrive / depart the plant and when clean modules are available after a clean module stock out


The events are stored as a time ordered event array. The event array is constructed from those event times that are initially known and updated as further event times are realised.

At this stage, we have allowed the user to input allocations into a spreadsheet named ‘Fill Order’. The new allocations entered could be a variation of the allocations created in the initial allocation stage or it could be an allocation created by the user. The new allocations can then be timed so that the schedules performance can be estimated.