Simulation

SIMULATION

SIMULATION: A model of a complex system and the experimental manipulation of the model to observe the results.

Systems that are best suited to being simulated are dynamic, interactive, and complicated.

Model: An abstraction of a real system.

It is a representation of the objects within the system and the rules that govern the interactions of the objects.

CONSTRUCTING MODELS

o Continuous simulation

* Treats time as continuous and expresses changes in terms of a set of differential equations that reflect the relationships among the set of characteristics.

* Meteorological models fall into this category.

o Discrete event simulation, consists of entities, attributes, and events.

* Entity: the representation of some object in the real system that must be explicitly defined

* Attribute: some characteristic of a particular entity

* Event: an interaction between entities

QUEUING SYSTEMS

o Queuing system: a discrete-event model that uses random numbers to represent the arrival and duration of events.

* The system is made up of servers and queues of objects to be served.

* The objective is to utilize the servers as fully as possible while keeping the wait time within a reasonable limit.

o To construct a queuing model, we must know the following four things:

* the number of servers

* the number of events and how they affect the system

 in order to determine the rules of entity interaction

* the distribution of arrival times

 in order to determine if an entity enters the system

* the expected service time

 in order