Discrete Event Simulation

Question 1

System

Answer 1

System: a collection of elements that act and interact with each other to Discrete: the system state changes instantaneously at separate points in time.
Continuous: the state changes continuously with respect to time.
the same goal

Question 2

Entities

Answer 2

Things that move around, change status, affect and are affected by other entities
Usually represent real things

Question 3

Resources

Answer 3

Entities compete for:
People
Equipment
Space
Entity seizes a resource, uses it, releases it
The resource is assigned to an entity
Can have several units of capacity
Seats at a table
Identical ticketing agents at an airline counter

Question 4

Queue

Answer 4

A place for entities to wait when they can’t move on
Can have a finite capacity
Attributes: characteristics of the entities, whose values are tied to the entities
All entities have the same attribute slots but different values for different entities
Time of arrival
Due date
Priority
Colour
Variables: global characteristics not ties to an entity
Reflects the characteristic of the whole model, not of specific entities
Used for many different kinds of things
Travel time between stations
Number of parts in a system
Simulation clock
Entities can access and change variables

Question 5

Planning

Answer 5

Identify entities
Resources
Key Processes
Develop a process map
Assign resources to processes
Identify entity flows
Assign inter-arrival, process and other times
Run
Analyse results