1. Semantic Social Network Analysis
Guillaume ERETEO

2. Social Network Analysis?
[Wasserman & Faust 1994] [Scott 2000] [Mika 2007]
• A science to understand the structure, the interactions
and the strategic positions in social networks.
• Sociograms
[Moreno, 1933]
• What for?
– To control information flow
– To improve/stimulate communication
– To improve network resilience
– To trust

3. Community
detection
• Global structure
• Distribution of actors
and activities
Influences the way
information is shared Influences the way actors behave
[Coleman 1988] [Burt 2000]

4. Centrality: strategic positions
[Freeman 1979]
Degree centrality:
Local attention
Closeness centrality:
Capacity to
communicate
Community detection:
Distribution of actors and
activities
beetweenness centrality:
reveal broker
"A place for good ideas"
[Burt 1992] [Burt 2004]

5. Critical mass

6. Balance Theory
[Heider 1958]

7. Computer networks
as social networks
[Wellman 2001]

8.  web 2.0 amplifies Network effect !

9. Semantic social networks
Millions of FOAF profiles
online
http://sioc-project.org/node/158

10. Social tagging
SCOT

11. SNA on the semantic web
[Paolillo and Wright 2006]
Foaf:knows
Foaf:interest
Rich graph representations reduced to simple
untyped graphs in order to apply SNA

12. The Semantic SNA Stack

13. Semantic paths in
social graphs
mainDish type
type
ingredient
likes
subclassOf
Food

14. Fabien
Mylène
e
knows Gérard
colleagu
e r
ist
fat
s
he
r
colleague d < familly > ( guillaume )c
olle
agu
m
e
ot
he
sibling parent
r
Michel
Yvonne
sister brother father mother

15. Fabien
Mylène
e
knows Gérard
colleagu
e r
ist
fat
s
he
r
colleague d < familly > ( guillaume )c = 3
olle
agu
m
e
ot
he
sibling parent
r
Michel
Yvonne
sister brother father mother

16. Closeness centrality
Cc<type>(y)
select ?y ?to pathLength($path) as ?length
sum(?length) as ?centrality where{
?y $path ?to
filter(match($path, star(param[type]),
param[type]
'sa'))
}
group by ?y

17. Parametrized Component
C<type>(G)
add{
?x semsna:isMemberOf ?uri
}
select ?x ?y genURI(<myorg>) as ?uri
from G
where {
?x $path ?y
filter(match($path, star(param[type]), 'sa'))
param[type]
}
group by any

18. SemSNA an ontology of SNA

19. [Wenger 1998]
[Conein 2004]
SemSNA an ontology of SNA

20. construct{
?y semsna:hasInDegree _:bO
_:bO semsna:isDefinedForProperty param[type]
_:bO semsna:hasValue ?indegree
_:b0 semsna:hasDistance param[length]
}
select ?y count(?x) as ?indegree{
?x $path ?y
filter(match($path, star(param[type])))
fitler(pathLength($path) <= param[length])
param[length]
}group by ?y
Parametrized n-Degree

21. Most popular manager in a work subnetworks
select ?y ?indegree{
?y rdf:type domain:Manager
?y semsna:hasInDegree ?z
?z semsna:isDefinedForProperty rel:worksWith
?z semsna:hasValue ?indegree
?z semsna:hasDistance 2
}
order by desc(?indegree)

22. Current Community
detection algorithms
• Hierarchical algorithms
– Agglomerative (based on vertex proximity):
• [Donetti and Munoz 2004] [Zhou Lipowsky, R. 2004]
– Divisive (mostly based on centrality):
• [Girvan and Newman 2002] [Radicchi et al 2004]
• Based on heuristic (modularity, randon walk, etc.)
• [Newman 2004], [Pons and Latapy 2005], [Wu and Huberman
2004]

23. Web sémantique
label
#tag27 #tag92
label
hasTag Semantic web
hasTag
#bk81 #bk34
hasBookmark hasBookmark
ShareInterest
#Guigui #Fabien
MentorOf
MentorOf Collaborate
#Michel

24. organization
organization
organization
name
Guillaume Erétéo
mentorOf
mail
guillaume.ereteo@orange-ftgoup.com
manage
contribute answers
mentorOf
contribute