Web Science & Social networks - KBS - KBS · Web Science & Social networks Signed Networks in...
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Summer 2019
Web Science & Social networks Signed Networks in Social Media
Professor: Prof. Dr. Wolfgang Nejdl Mentor: Philipp Kemkes Student: Masih Ghaderi
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Signed graph
A signed graph is a graph in which each edge has a positive or negative sign
In social psychology, signed graphs have been used to model social situations,
with positive edges representing friendships and negative edges enmities
between nodes, which represent people
Web Science
Introduction to signed networks
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Positive and negative links in online data
Discussion lists are filled with controversy and disagreement
A social network consists of a mixture of both positive and negative
interactions, co-existing in a single structure
Fundamental ingredients
1. Large-scale datasets from social applications
2. Theories of signed networks
Web Science
Introduction to signed networks
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Structural balance theory
Balance theory can be viewed as a model of likes and dislikes
Web Science
Introduction to signed networks
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Theories of signed networks: Balance
Balanced triangles with:
• three positive edges : “the friend of my friend is my friend”
• one positive and two negative edges : “the friend of my enemy is my enemy”
• “the enemy of my friend is my enemy”
• “the enemy of my enemy is my friend”
Extension (Weak structural balance)
• Eliminating the assumption that “the enemy of my enemy is my friend”
Web Science
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Balanced Unbalanced
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Theories of signed networks: Status
A positive directed link indicates that the creator of the link views the recipient as
having higher status
A negative directed link indicates that the recipient is viewed as having lower
status.
Comparing the two theories
A links positively to a user B
B in turn links positively to a user C
If C then forms a link to A, what sign should we
expect this link to have?
Web Science
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social network structures
Three widely-used Web sites:
1. The trust network of Epinions: users create signed directed relations to each
other indicating trust or distrust.
2. The social network of the technology blog Slashdot: users designate others as
“friends” or “foes”
3. The network defined by votes for Wikipedia admin candidates
A positive vote as corresponding to a positive link from the
voter to the candidate
A negative vote as a negative link.
Web Science
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Datasets
In all networks the background proportion of positive edges is about the same,
with roughly 80% of the edges having a positive sign.
Web Science
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Datasets
the counts of the four possible signed
Web Science
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Analyzing positive and negative ties
Characterize the parts of the network in which positive ties are more likely to
occur
Web Science
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Conclusion
One of the best scientific research in two theories of signed social networks
(balance and status)
Social networks often reflect a mixture of positive and negative inks
These two theories make different predictions for the frequency of different
patterns of signed links
Differences in results between the datasets highlight some interesting aspects
of how the sites present information
Strong evidence for a weak form of structural balance when the networks
are viewed as undirected graphs
Balance theory no longer apply when the networks are viewed as directed
graphs
Web Science
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Thank you