6.6 Queuing and simulation
A queue is a waiting line of work needing to be processed. Simple queues can be analyzed with queuing models to estimate waiting time and queue length. More complex situations are analyzed using simulations. Simulation is a technique in which systems are modeled using a computer program designed to mimic a real system. Simulations may be run before a real system becomes operational to aid in design, to see how the system might react to changes in operating rules, and to evaluate the system's response to changes in its structure.