# Process - (System) Simulation

### Table of Contents

## About

process simulation.

## Articles Related

## Simulation Component

The basic model components are

- queues, (Queue theory to model finite resources)
- stochastic distributions (based on random number streams) to model the time

Each collect and report statistical data about their use.

In a process-oriented model, queues are used to synchronise simulation processes which are conceptually acting concurrently. For example, in a loading zone of a container terminal, arriving trucks had to wait until a van carrier was available for service.

Patterns of synchronisation between process:

- Capacity constrained resources. Processes wait until sufficient resource capacity is available to proceed.
- Producer/consumer relationships with unlimited capacity buffers (class Bin).
- Conditional waiting until a specified model state has occurred.
- direct process co-operation (master-slave relationships)

A single simulation run will not offer reliable results, since they are the outcome of a stochastical process.

## Other

### Discrete event simulation

Discrete event simulation describes a process with a set of unique, specific events in time. They can simulate almost any process.

All system state changes are supposed to happen at discrete points in time. Between such events the system state is assumed to remain constant. Discrete-event simulation is therefore particularly suitable for systems in which relevant changes of state occur suddenly and irregularly, like queueing networks for example.

## Library / Client

- Drag-and-drop graphical interfaces:
- Automod,
- ProModel,
- Simio,
- Simul8,
- Witness

## Book

- Jerry Banks, John S. Carson, Barry L. Nelson: Discrete-event Systems Simulation. Upper Saddle River: Prentice-Hall, 1999
- Les Oakshott: Business Modelling and Simulation. London, Pitman, 1997