1. Noncooperative Rumor Blocking
Lecture 7-2
Noncooperative Rumor Blocking
Guangmo Tong, Weili Wu, Ding-Zhu Du
│ University of Texas at Dallas │
Social network analysis [SNA] is the mapping and measuring of relationships and flows between people, groups, organizations, computers or other information/knowledge processing entities.
The nodes in the network are the people and groups while the links show relationships or flows between the nodes.
The advantage of social network analysis is that, unlike many other methods, it focuses on interaction (rather than on individual behavior).
Network analysis allows us to examine how the configuration of networks influences how individuals and groups, organizations, or systems function.

2. Outline Rumor in Social Network Game Formulation Results
Possible Future Work
Brief overview of social networks
How to build applications on top of the social network
–  Think about a social network being MS Windows, We can build applications on it.

3. Social networks
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4. Social Network Social network is a social structure
made up of individuals and relations
between these individuals
Social network provides a
platform for influence diffusion
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5. When misinformation or rumor spreads in social networks, what will happen?
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6. A misinformation said that the president of Syria is dead, and it hit the twitter greatly and was circulated fast among the population, leading to a sharp, quick increase in the price of oil.
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7. In August, 2012, thousands of people in Ghazni province left their houses in the middle of the night in panic after the rumor of earthquake. In
August, 2012, thousands of people in Ghazni province
left their houses in the middle of the night in panic
after the rumor of earthquake, which said that a major
earthquake would hit the area until 5 am [3]. Believing
in it, many people from the Ghazni city and some other
districts of the province left their house and spent the
whole night outside. The panic spread by the rumor
was so intense that the people, who were in thousands,
did not dare to return to their houses till morning.
Mirwais, a resident of Ghazni city, talked to a news
agency about this announcement. Later, the imams of
the mosques had started believing in it and according
to the statement made by Mirwais, Then, imams of
mosques also started announcing about the earthquake.
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8. Control the spread of rumors
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9. “Love Obama” I hate Obama, the worst president ever I love Obama
Obama is fantastic
Obama is great!
No Obama in 2012!
A fundamental understanding of communication has always been at the center of a politician's arsenal, but a firm grasp on the future of communication can be the secret weapon that wins the war. For Franklin D. Roosevelt, it was radio. For John F. Kennedy, it was television. And for Barack Obama, it is social media.
The 2008 Obama Presidential campaign made history.  Not only was Obama the first African American to be elected president, but he was also the first presidential candidate to effectively use social media as a major campaign strategy.
During his campaign, Obama has made his Web 2.0 presence known. He has over 1.5 million friends on MySpace and Facebook, and he currently has over 45,000 followers on Twitter. This personal activity in social networks allows him to quickly get the word out across multiple platforms.
He cannot be the next president!
Positive
Negative

10. Rumor Blocking Problem7 6 9 5 8 10 3 4 11 2 1
Yellow nodes are bridge ends. 12 14 13
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11. Example Y
0.6
Inactive Node
0.2
0.2
0.3
Active Node
Newly active
node X U
0.1
0.4
Successful
attempt
0.5
0.3
0.2
Unsuccessful
attempt
0.5 w v
Stop!

12. P2P Independent Cascade
In each step of IC model, active node uniformly chooses an inactive neighbor to try.
At beginning, each node u randomly choose a permutation of out-neighbors. If u is activated at time t, then it will try to activate the jth out-neighbor at time t+j.
PIC model fits for mobile
communication.
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13. Background Several agents want to block the rumor.
Network is too large to make cooperation.
What guaranteed performance can be reached?
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15. Outline Rumor in Social Network Game Formulation Results
Possible Future Work
Brief overview of social networks
How to build applications on top of the social network
–  Think about a social network being MS Windows, We can build applications on it.

16. Game Formulation
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17. Priority Rumor has the highest priority. All agents have equal chance.
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18. Utility System ？
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20. Mixed Strategy
Utility functions
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21. Nash Equilibrium
Theorem (Nash, 1951)

22. A Beautiful Mind- John Nash

23. Theorem 1
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24. Outline Rumor in Social Network Game Formulation Results
Possible Future Work
Brief overview of social networks
How to build applications on top of the social network
–  Think about a social network being MS Windows, We can build applications on it.

25. Lemma 1
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26. What is a submodular function?
Consider a function f on all subsets of a set E.
f is submodular if

27. Monotone Increasing
f is monotone increasing if

28. Lemma 2
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29. Lemma 2
Definition
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30. Claim 1
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31. 1 2 3

32. 1 1 2 3 2 3 1 1 2 3 2 3

33. 1 2 3

34. 1 2 3

35. Corollary of Lemma 2
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36. Theorem 2
Proof
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40. Theorem 3
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44. Outline Rumor in Social Network Game Formulation Results
Possible Future Work
Brief overview of social networks
How to build applications on top of the social network
–  Think about a social network being MS Windows, We can build applications on it.

45. Cooperative Rumor Blocking
Community detection with game-approach
Assign protectors into communities
Find better locations in each community
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46. Thank you!
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47. Theorem 4
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