Presents the importance of social graphs in the context of DTN routing. This presentation was given in IANLab meeting, on Dec 21st, 2010 @ SITI.

1. How Important Social Graphs are
for DTN Routing
Universidade Lusófona, IANLab meeting
Waldir Moreira
21/12/2010
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2. Agenda
 Definitions
 Motivation
 Problems
 Consequences
 What can be done?
 Current idea
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3. Definitions - Social Graph
 Vertices = nodes
 Edges = levels of social relationship
• Family
• Friends
• Close Friends
• Familiar strangers
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4. Definitions – Types of Social Graph
 Online
• Pure social networks: Facebook, Orkut
• With social network: LinkedIn, YouTube
 Offline
• Traces, daily life
NOTE: At some point they intertwine
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6. Motivation – Online Social Graphs
 Researchers in psychology and sociology
• Practice of inferring meaningful
relationships from social network
connections alone
Are social links valid indicators of real
user interaction?
[Wilson et al. 2009] C. Wilson, B. Boe, A. Sala, K. P. N.
Puttaswamy, and B Y. Zhao, "User Interactions in
Social Networks and their Implications." 4th ACM
European conference on Computer systems, 2009.
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7. Motivation – Offline Social Graphs
 Mapping from the mobility process
generating contacts to the aggregated social
graph
How important contact aggregation is
while determining social graph?
[Hossmann et a. 2010] T. Hossmann, T. Spyropoulos,
and F. Legendre, “Know Thy Neighbor: Towards
Optimal Mapping of Contacts to Social Graphs for
DTN Routing.” IEEE INFOCOM'10, 2010.
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8. Problem
 Social graph does not represent user
interaction graph
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9. Problem
 Majority of interactions occur only on a small
subset of social links [Wilson et al. 2009]
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10. Problem
 Social metrics capture part of mobility process
[Hossmann et a. 2010]
– Node homogeneity
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11. Problem
 Information is not fully available (Black Holes
[Ye et al. 2010])
– Privacy
– Confidentiality
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12. Consequences
 Disconnected social graph
 Presence of non-useful links
 Lost nodes
☹ Performance degradation of proposals ☹
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13. What can be done?
 Build social graph
– Considering mobility process
– Adding information from virtual world
– As well as interets
– Timely fashion [Ferreira et al. 2010]
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14. Current idea
 Combine aggregation techniques [Hossmann
et a. 2010]
– Most recent (i.e., with more predictive power)
– Most frequent (i.e., a stronger social link)
– Select edges that represent regular contacts
Consider number of contacts as well as
their frequency to determine the quality
of edges comprised by the social graph
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15. References
[Wilson et al. 2009] C. Wilson, B. Boe, A. Sala, K. P. N.
Puttaswamy, and B Y. Zhao, "User Interactions in Social
Networks and their Implications." 4th ACM European
conference on Computer systems, 2009.
[Hossmann et a. 2010] T. Hossmann, T. Spyropoulos, and F.
Legendre, “Know Thy Neighbor: Towards Optimal Mapping of
Contacts to Social Graphs for DTN Routing.” IEEE INFOCOM'10,
2010.
[Ye et al. 2010] S. Ye, J. Lang, and F. Wu, "Crawling online social
graphs." Asia Pacific Web conference, 2010.
[Ferreira et al. 2010] A. Ferreira, A. Goldman, and J.Monteiro,
"Performance evaluation of routing protocols for manets with
known connectivity patterns using evolving graphs." Journal
Wireless Networks, vol. 16, issue 3, 2010.
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16. Thanks!
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