Advantages of simulation
Download
1 / 14

Advantages of simulation - PowerPoint PPT Presentation


  • 72 Views
  • Uploaded on

Advantages of simulation. New policies, operating procedures, information flows and son on can be explored without disrupting ongoing operation of the real system .

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Advantages of simulation' - pancho


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Advantages of simulation
Advantages of simulation

  • New policies, operating procedures, information flows and son on can be explored without disrupting ongoing operation of the real system.

  • New hardware designs, physical layouts, transportation systems and … can be tested without committing resources for their acquisition.

  • Time can be compressed or expanded to allow for a speed-up or slow-down of the phenomenon( clock is self-control).

  • Insight can be obtained about interaction of variables and important variables to the performance.

  • Bottleneck analysis can be performed to discover where work in process, the system is delayed.

  • A simulation study can help in understanding how the system operates.

  • “What if” questions can be answered.


Disadvantages of simulation
Disadvantages of simulation

  • Model building requires special training.

  • Simulation results can be difficult to interpret.

  • Simulation modeling and analysis can be time consuming and expensive.

  • Many simulation software have output-analysis.


Discrete and continues systems
Discrete and Continues Systems

  • A discrete system is one in which the state variables change only at a discrete set of points in time : Bank example


Discrete and continues systems cont
Discrete and Continues Systems (cont.)

  • A continues system is one in which the state variables change continuously over time: Head of water behind the dam



Definitions
Definitions

  • System: is a collection of entities which are logically related and which are of interest to a particular application.

  • EntityAn object of interest in the system : Machines in factory

  • AttributeThe property of an entity : speed, capacity

  • ActivityA time period of specified length :welding, stamping

  • StateA collection of variables that describe the system in any time : status of machine (busy, idle, down,…)

  • EventA instantaneous occurrence that might change the state of the system


Introduction
INTRODUCTION

  • A queuing system consists of one or more servers that provide service of some sort to arriving customers.

  • Customers who arrive to find all servers busy generally join one or more queues (lines) in front of the servers, hence the name queuing systems.

  • There are several everyday examples that can be described as queuing systems, such as bank-teller service, computer systems, manufacturing systems, maintenance systems, communications systems and so on.



Components of a queuing system1
Components of a Queuing System:

  • 1- Population of Customers can be considered either limited (closed systems) or unlimited (open systems).

  • Unlimited population represents a theoretical model of systems with a large number of possible customers (a bank on a busy street, a motorway petrol station).

  • Example of a limited population may be a number of processes to be run (served) by a computer or a certain number of machines to be repaired by a service man

  • Customers may be people, machines of various nature, computer processes, telephone calls,


Components of a queuing system2
Components of a Queuing System:

  • 2- Arrival defines the way customers enter the system. Mostly the arrivals are random with random intervals between two adjacent arrivals. Typically the arrival is described by a random distribution of intervals also called Arrival Pattern.


Components of a queuing system3
Components of a Queuing System:

  • 3- Queue represents a certain number of customers waiting for service (of course the queue may be empty).

  • The customer being served is considered not to be in the queue.

  • There are two important properties of a queue: Maximum Size and Queuing Discipline


Components of a queuing system4
Components of a Queuing System:

  • Maximum Queue Size (also called System capacity) is the maximum number of customers that may wait in the queue (plus the one(s) being served).

  • Queue is always limited, but some theoretical models assume an unlimited queue length. If the queue length is limited, some customers are forced to renounce without being served


Components of a queuing system5
Components of a Queuing System:

  • Service represents some activity that takes time and that the customers are waiting for.

  • Output represents the way customers leave the system. Output is mostly ignored by theoretical models, but sometimes the customers leaving the server enter the queue again


Components of a queuing system6
Components of a Queuing System:

  • Queuing Discipline represents the way the queue is organized (rules of inserting and removing customers to/from the queue).

  • The ways are these ways:

    1) FIFO (First In First Out) also called FCFS (First Come First Serve) - orderly queue.

    2) LIFO (Last In First Out) also called LCFS (Last Come First Serve) - stack.

    3) SIRO (Serve In Random Order).

    4) Priority Queue, that may be viewed as a number of queues for various priorities.


ad