"The representation of the behaviour or characteristics of one system through the use of another system, especially a computer program designed for the purpose."
That's the dictionary defintion of simulation, but how does it relate to logistics and materials handling? Since modern logistics began, managers have been looking for ways to accurately predict the effects of changes to a materials handling operation. Will moving a certain type of item to a different rack produce more efficient results, or just create new problems? With experience it's possible to make good predictions, but the complexity of a materials handling operation means it's very difficult to have a lot of confidence in them.