# Discrete event simulation

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• Oct 15th 2012, 08:29 AM
mathlearn
Discrete event simulation
Is it correct to say that a discrete-event simulation reviews the status of the system continuously ? or no ?
• Oct 15th 2012, 06:39 PM
chiro
Re: Discrete event simulation
Hey mathlearn.

Can you elaborate on this? Maybe provide some mathematical descriptions of the things involved, what you are simulated and what you are comparing to?
• Oct 16th 2012, 01:59 AM
mathlearn
Re: Discrete event simulation
I am learning about Stimulation and this is a question like a true or false:

"Discrete-event simulation reviews the status of the system continuously"

In discrete-event simulation (DES), the operation of a system is represented as a chronological sequence of events. Each event occurs at an instant in time and marks a change of state in the system.[1] For example, if an elevator is simulated, an event could be "level 6 button pressed", with the resulting system state of "lift moving" and eventually (unless one chooses to simulate the failure of the lift) "lift at level 6".

A number of mechanisms have been proposed for carrying out discrete-event simulation, among them are the event-based, activity-based, process-based and three-phase approaches (Pidd, 1998). The three-phase approach is used by a number of commercial simulation software packages, but from the user's point of view, the specifics of the underlying simulation method are generally hidden.

So that this makes the statement true or false ?
• Oct 16th 2012, 02:28 AM
chiro
Re: Discrete event simulation
It looks like you are describing a situation where you are using fixed interval lengths between successive chronological operations (i.e. in time) that are close enough together as to give an "almost" continuous feel.

If this is the case however, you need to consider the nature of the interval length and its relation to the resolution of events happening.

For example if events happen with the finest revoution of 10 events per unit interval and you have an interval size of 0.01, then this is OK but if you have an interval size of say 0.01 but the frequency of events is much higher (say 1000 per unit) then you will run into problems.
• Oct 16th 2012, 08:18 AM
mathlearn
Re: Discrete event simulation
Thank you for the explanation.

Since I don't have any data and the statement is like a true / false question.

Based on the definition that I mention above, could you please help me in figuring out if the following statement is True or False ?

"Discrete-event simulation reviews the status of the system continuously"
• Oct 16th 2012, 05:20 PM
chiro
Re: Discrete event simulation
This hint should give you the way to get an answer:

A continuous representation needs infinitely many samples or values for each corresponding element of the domain to be described. But being discrete means that you only have a finite number of samples.

So what can you conclude from that?

If you are going strictly to definitions, the above hint is something to consider. If you are considering the general qualities rather than a strict definition, then the prior response I have given above is something to consider.