Explain cohesive subgroups are groups of members that interact with each other more within the group frequently than with others outside of the group
Explain cohesive subgroups are groups of members that interact with each other more within the group frequently than with others outside of the group
Explain cohesive subgroups are groups of members that interact with each other more within the group frequently than with others outside of the group
Select results in subgraph of potential members from original social graph Many types of criteria to determine whether someone is in the possible subgroups Use network centrality because
Select results in subgraph of potential members from original social graph Choose network centrality because widely used and simple to calculate High betweenness Good measure of subgroup clusters (eg. Tyler et al., 2005, Newman and Girvan, 2004) Degree centrality measures the number of direct connections to other nodes Betweenness centrality measures the extent to which a node can act as an intermediary or broker to other nodes Closeness centrality measures how many steps on average it takes to reach every other node in the network
Select results in subgraph of potential members from original social graph
Select results in subgraph of potential members from original social graph
Explain cohesive subgroups are groups of members that interact with each other more within the group frequently than with others outside of the group
Select results in subgraph of potential members from original social graph
Select results in subgraph of potential members from original social graph
Select results in subgraph of potential members from original social graph
Explain cohesive subgroups are groups of members that interact with each other more within the group frequently than with others outside of the group
Densely connected graph
Top 10 people in Friend View in friends network do form a cohesive subgroup
Select results in subgraph of potential members from original social graph
Select results in subgraph of potential members from original social graph
Select results in subgraph of potential members from original social graph
Select results in subgraph of potential members from original social graph
Finding Cohesive Subgroups and Relevant Members in the Nokia Friend View Mobile Social Network - Presentation Transcript
Finding Cohesive Subgroups and
Relevant Members in the Nokia
Friend View Mobile Social Network
Alvin Chin
Member of Research Staff
Mobile Social Networking Group
Nokia Research Center, Beijing
August 30, 2009
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Agenda
1. Motivation
2. Problem
3. Solution
4. Finding cohesive subgroups and important
members
5. Case study: Nokia Friend View
6. Results
7. Conclusion and Future Work
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Many people want to be my “friend”
Who should I add to my social network as friends?
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
How can we find who are
the relevant members in
the social network?
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Solution
• Create method for finding cohesive subgroups
and their relevant members based on SCAN
method (Chin and Chignell, 2008)
• Apply it to Nokia Friend View network to see
its viability and to describe its social behaviour
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Agenda
1. Motivation
2. Problem
3. Solution
4. Finding cohesive subgroups and important
members
5. Case study: Nokia Friend View
6. Results
7. Conclusion and Future Work
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Cohesive subgroups
• Group of members having more and frequent
interactions with each other than outside
group
12 15
A B
A
B
6 7
8
10
E C D
F
Clique K-plex
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Finding cohesive subgroups
• How
• Social network analysis, centrality, clustering
• But no automated or systematic method
• My work: modified SCAN method adapted from
Chin and Chignell (2008)
Chin, Alvin and Chignell, Mark(2008). Automatic detection of
cohesive subgroups within social hypertext: A heuristic approach,
New Review of Hypermedia and Multimedia,14:1, 121 — 143
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Modified SCAN method: 1. Select
• Find only potential members and remove the
rest that do not meet criteria (cutoff)
• Possible selection criteria
• Network centrality (Frievolt and Bielikova,
2005; Newman and Girvan, 2004)
• Subnet density (Herring et al, 2004)
• Indegree/outdegree (Kumar et al, 1999; Ali-
Hasan and Adamic, 2007)
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Network centrality
A
15 C
8 B 11
12 6 10 6
20
8 16
10
D
6 E
F
17 15
12
G H
Betweenness Degree centrality Closeness
centrality centrality
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Determining cutoff centrality
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Modification to original SCAN Select
• Use cutoff betweenness centrality, then cutoff
degree and closeness centrality
• Associated with strong sense of community
(Chin and Chignell, 2007)
• All members whose centrality < cutoff are
removed
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Modified SCAN method: 2. Collect
• Find subgroups from interactions amongst
potential members found in Select
• Use weighted average hierarchical clustering
• Computationally efficient than k-plex analysis
(Chin and Chignell, 2007)
• Output is dendrogram – set of nested, non-
overlapping clusters
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Weighted average hierarchical clustering
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Agenda
1. Motivation
2. Problem
3. Solution
4. Finding cohesive subgroups and important
members
5. Case study: Nokia Friend View
6. Results
7. Conclusion and Future Work
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Nokia Friend View on the web
(friendview.nokia.com)
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Nokia Friend View on mobile
(friendview.nokia.com)
Map Status updates from Comments to status
friends and me update
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Finding subgroups and relevant members in
Friend View
• Does the friend network influence the
interaction network? Are the connections in
the interaction network representative of the
friend connections in the friend network?
• Do subgroup members send more comments
than others in the interaction network?
• Do subgroup members have more friends than
others in the interaction network?
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Agenda
1. Motivation
2. Problem
3. Solution
4. Finding cohesive subgroups and important
members
5. Case study: Nokia Friend View
6. Results
7. Conclusion and Future Work
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Relevant members in friend network – top 10
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Subgroups in friend network – top 10
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Relevant members in interaction network –
top 10
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Subgroups in interaction network – top 10
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Does the friend network influence the
interaction network? Yes!
• 9 out of top 10 in friend network are in interaction network
• 5 out of top 10 in friend network are in top 10 interaction
network
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Do subgroup members send more comments
and have more friends than others in the
interaction network? Yes!
Feature Subgroup members Interaction network
Avg # of comments 212.9 7.775
Avg # of friends 57.8 3.075
• Members that are friends of each other, are clustered together
from their conversations to form subgroups
• Members of cohesive subgroups interact with each other
significantly more than non-subgroup members and are most
likely to be friends with each other
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Conclusions
• Described modified SCAN method for finding
cohesive subgroups and relevant members
• Applied method to Nokia Friend View
• Discovered
• Top 10 members in the interaction network
are friends of each other
• Subgroup members have more comments
and friends
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Future work
• Content analysis of messages in Friend View
• Analyze the Friend View dataset in different
time periods
• Based on previous work: TorCamp study
(Chin and Chignell, 2008)
• Create a recommendation and ranking
algorithm based on our method
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
friendview.nokia.com
Alvin Chin – Social Intelligence and Networking workshop, IEEE SocialCom’09
Presentation from the Social Intelligence and Netwo more
Presentation from the Social Intelligence and Networking workshop at the IEEE Social Computing conference in Vancouver, Canada on Sunday, August 30, 2009 less
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