LIS590SF - Social Computing (Fall 2012),
Assignment #3
Submitted by Craig Evans
28 July 2017
Simulating the Network
Abstract
There are a number of software packages that allow the user to create a simulated event, such
as a human or computer virus outbreak, and model the growth behavior. The internet and
social networks presents us with a unique opportunity to create a simulation that adds a
random element by using real users social interactions as the catalyst for modeling the event.
Using a Facebook application, and seeding a single user, this study examines the spread of a
“virus” through a social system.
Introduction
Computer simulations model events and interactions, but overlook the most random element
in any human interaction – and that is the human actors themselves.
Facebook has just hit 1 billion users1. Studies have shown that the average degree of separation
between any two users in Facebook is 3.74-4.742,3. This means that in our online lives, we are
more connected than the six degrees of separation proposed by Stanley Milgram's 1967 "smallworld experiment"4. How can we leverage this level of connectedness to simulate the spreading
of a virus?
In popular culture, movies such as The Matrix, The Thirteenth Floor, and Existenz explore
worlds in which the human characters are not human at all, but actors within an artificial
network. This project is not as sweeping as the artificial life presented in the movies, but aims
to use Facebook as the network, and a custom application running within Facebook as a virus.
Methodology
The viral “contagion” will be established using the model as seen in Figure 1.
Computer simulation of the model had the Contact Rate (c) and Total Population (N) as set
values (6 and 10000 respectively), but in the “real world” some people are in contact with more
people, and the population is much larger – but constrained by the number of people in the
total network, and not the population as a whole.
Infectivity (I) will remain at 25%, and Average Duration of Illness will be set to 2 days. The initial
Infectious Population will be 1.
Change the footnotes to proper citations in next version
1
http://bits.blogs.nytimes.com/2012/10/04/facebook-passes-1-billion-active-users/
http://www.bbc.co.uk/news/technology-15844230
3 http://www.cbsnews.com/8301-501465_162-57329618-501465/six-degrees-of-separationfacebook-says-more-like-4.74/
4 Milgram, Stanley. "The Small World Problem". Psychology Today, 1(1), May 1967. pp 60 – 67
2
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LIST590SF – Assignment #3
Submitted by Craig Evans
28 July 2017
Need to vary the model a little – I want to set up the zombie apocalypse. If a person is
contagious, but not infected, if they come into contact with someone infected, they will move
from contagious to being infected.
Figure 1 - Base Model for Simulation
Selected Variables
10,000
People
7,500
5,000
2,500
0
0
2
4
6
8
10
12
14
16
Time (Day)
18
20
22
24
26
28
30
Infectious Population I : current
Recovered Population R : current
Susceptible Population S : current
Figure 2 - "Ideal" Computer Model of Simulation
To Be Done:
Need to establish a notification mechanism (email? Hit a webserver with a message that can
put the response into a db?), each time someone accepts an infection from someone else, I need
to know:


Who in being infected
Who sent the infection
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LIST590SF – Assignment #3
28 July 2017
Submitted by Craig Evans
 Where the person is located (I’d like to see how far this spreads – with my friend list I can hit
the US and Australia … but where does it go from there?)
Facebook code – biggest challenge.
Put together a web page so people can see progress of the “pandemic” – with an explanation of
the project.
Analysis to look at:
How far can you spread something online as a single user?
How long does it take to propagate?
How long does it take to die down?
Release the plague?? In a perfect worlds I would do it on Halloween to capitalize on the
“holiday” nature of ghoulish tendancies.
Despite the fact I am going to shroud the application as a zombie style contagion, the
underlying growth and reach research is what I am trying to get to – it just needs to be fun so
that people will voluntarily participate.
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