Computer Simulation Final Project

SNHU

Final Project

Milestone 3

Heather Moore

3/23/2014

The following document outlines the creation of a 3D FlexSim simulation model. The model is a mock-up of an airport security checkpoint that is looking for ways to speed up wait times and still thoroughly check passengers for weapons and unapproved items.

IT 630 Final Project Heather Moore

Table of ContentsExecutive Summary.........................................................................................................................2

Problem formulation........................................................................................................................3

Description of simulation........................................................................................................3

Problem situation.....................................................................................................................3

What-if questions.....................................................................................................................3

Base model and alternative models.................................................................................................6

Input analyses..................................................................................................................................7

Verification and Validation.............................................................................................................8

Calculation of number of runs.........................................................................................................9

Output analyses..............................................................................................................................10

Cost-benefit analysis......................................................................................................................10

Summary........................................................................................................................................11

Figures

Figure a - OFD Model 1..................................................................................................................4Figure b - OFD Model 2..................................................................................................................5Figure c - Base Model......................................................................................................................6Figure d - Alternative Model...........................................................................................................7Figure e - Comparison of the two models.......................................................................................9Figure f - Average Staytime for Scanner 1 Model..........................................................................9Figure g - Average Staytime for Scanner 2 Model........................................................................10

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Executive Summary

The project required the creation of a real-world problem in FlexSim’s 3D simulation

software. We were to create a situation that we could demonstrate an issue and find a solution.

My model is an airport security check-point where the waiting time to go through the scanner

was excessive and needed to be shortened to ensure passengers reached their gate on time. The

first model demonstrated the wait times and flow of one metal detector and x-ray scanner while

the second model demonstrated the use of two metal detectors and x-ray scanners. The wait

times decreased a significant amount with the second model.

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Problem formulation

Description of simulation

The simulation I am going to create is the security checkpoint at an airport. There will be

multiple scanners for luggage and people going through the checkpoint. Depending on the

number of people going to the gates will affect how busy or slow the checkpoint becomes. Some

passengers will not pass the initial security scan and will have to continue to the manual search

area to be cleared. This will affect overall time in the check-point which will slow down the

flow.

Problem situation

There are long lines of passengers going through the security checkpoint. The long waits

are causing people to be late for their flights. There needs to be a solution determined for

speeding up the lines but still maintaining the security of all passengers.

What-if questions

What if there was more than one scanner location for the passengers to move through?

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System and simulation specification

Object Flow Diagrams

Figure a - OFD Model 1

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Figure b - OFD Model 2

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Base model and alternative models

Figure c - Base Model

The base model contains one metal detector scanner and one x-ray scanner for luggage.

Processing passengers through the metal detector is causing long wait times of about 80 minutes.

This is causing passengers to be late or miss their flights due to the long wait times. The base

model also has a manual search area for those passengers who are picked for further screening.

Currently the metal detector takes anywhere between 10 to 25 minutes to scan a passenger. If

they are selected for further scanning then they are sent to the manual scan station where it can

take another 5 to 20 minutes to process them.

The passenger’s luggage must go through an x-ray scanner that takes between 3 to 10

minutes to scan. If the content doesn’t pass the x-ray scan then it is moved to the manual search

area to be further inspected by the security. The manual search for the luggage takes between 5

to 10 minutes to be searched. The average wait time for the manual scan area is about 10 minutes

long.

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Figure d - Alternative Model

The alternative model contains double the metal detectors and x-ray machines for faster

processing. The amount of time it takes to scan each person and luggage is the same for each

scanner but now there are two scanners doing the same amount of work as previously there was

only one. I anticipate that this will speed up the process time significantly.

Input analyses

The model runs a 16 hour day (960 minutes) to account for the airport being open from

7:00am to 11:00pm daily. There are two separate flow items created one that represents

passengers and the other that represents their luggage. Passengers were assigned item number 1

and luggage was assigned item number 2. These item numbers help control the flow of where

each is processed when going through the screening checkpoint. Each passenger is also randomly

assigned a shirt color to help tell each person apart and watch them flow through the model.

In the base model I originally had the queue send to port based on expression which sent

item 1 to port 1 and item 2 to port 2. The manual scan queue is still set this way but I quickly

realized this was not going to work for the alternative model’s first queue where there were more

ports so I was able to pull into the processor the relevant flow item by changing the setting for

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Input under the Flow tab of the processor. This ensures that the passengers are going through the

metal detector and the luggage is going through the x-ray scanner. The processor then randomly

chooses weather to send the item to the manual scan queue or the corresponding sink. Once

processed through the manual scan all items flow to the sink.

The processor times were determined by taking into account that some people walk

slower, have trouble taking off their shoes, or loading their luggage on the x-ray scanner

therefore the times ranged from 10 to 25 minutes. The luggage processor was place at 3 to 10

minutes of time for the operator to scan the luggage. This time takes into consideration that some

bags will be packed more than others making it harder to fully x-ray. Both the manual search

processors were set to process items between 5 to 20 minutes so that the operator had time to

fully search the luggage or passenger if there were questions about what they were taking on the

plane.

Verification and Validation

I followed three sets of data to determine if the alternative model had better results than the

base model. The main one was the average wait time of the first queue in the check-point. This

showed a significant amount of time passengers were waiting to go through security. I also

tracked the number passengers and the number of luggage that was processed overall. This

showed that there were only about 55 people being processed through the security check-point

over the course of 16 hours. After adding the second check-point scanners the number of people

almost doubled.

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Figure e - Comparison of the two models

Calculation of number of runs

Using the Simulation Experimenter tool I monitored the variable for Max Wait Time on the first queue in the sequence.

Figure f - Average Staytime for Scanner 1 Model

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Figure g - Average Staytime for Scanner 2 Model

Output analyses

What if there was more than one scanner location for the passengers to move through?

With the addition of a second scanning area the wait time decreased by 94%. This

significantly saves the passengers time when trying to catch their plane. There was also a 67%

increase in the number of passengers that were processed through the entire check-point. Lastly

the processed luggage was increased by 11%. Overall the addition of a second security scanning

area increased numbers across the board.

Cost-benefit analysis

My models did not look at the cost of running each security check-point. The second model

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Airport Security Model Avg Wait TimePassengers Processed

Luggage Processed

Scanner 1 95.84 55 98Scanner 2 5.78 92 109

Totals 94% 67% 11%


would definitely cost more to run due to the increase in operating staff and extra machines.

Although looking at the number of passengers that went through on one work day it doesn’t

seem like the cost of running two scanners would be worth it for the number of passengers who

are traveling through the airport. Now if I had setup the sources differently to allow an increase

in the throughput of passengers this might be a better solution.

SummaryI learned a great deal by creating this model. I was able to apply what I had learned

during the course to my models to achieve the results I had envisioned. There is still a lot that I

could have incorporated into my models but I found many of the tutorials to be lacking in

explanation of how to use the system and how to manipulate the data to create the model I

wanted. I am really happy with the final result though. I have to admit at first I didn’t think I

would be able to successfully complete the final project.

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Technology

Computer Simulation Final Project