community detection from a computational social science perspective

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This is the talk I gave at the Lipari Summer School on Computational Social Science, 2014. Which are the sociological strategies to detect communities in social media? How we can define a community form a computational social science point of view?

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  • COMMUNITY DETECTION FROM A COMPUTATIONAL SOCIAL SCIENCE PERSPECTIVE Davide Bennato Universit di Catania dbennato@unict.it @tecnoetica
  • LIPARI23/07/2014 DAVIDEBENNATO
  • LIPARI23/07/2014 DAVIDEBENNATO
  • LIPARI23/07/2014 DAVIDEBENNATO COMMUNITY: (brief) SOCIOLOGICAL HISTORY
  • LIPARI23/07/2014 DAVIDEBENNATO Ferdinand Tnnies: Gemeinschaft und Gesellschaft (1887) Community: groupings based on feelings of togetherness and on mutual bonds Society: groups that are sustained by it being instrumental for their members' individual aims and goals
  • LIPARI23/07/2014 DAVIDEBENNATO Georg Simmel: Sociability (1908) All the forms of association by which a mere sum of separate individuals are made into a society (Ritzer) Social geometry: dyad (relation between two entities), triad (relation between three entities) Circles: social structure surrounding people based on a special interest David Armano: https://www.flickr.com/photos/7855449@N02/2779601063
  • LIPARI23/07/2014 DAVIDEBENNATO http://www.lsu.edu/faculty/fweil/SimmelCircles.htm
  • LIPARI23/07/2014 DAVIDEBENNATO I thus designate sociability as the play-form of sociation. Its relation to content- determined, concrete sociation is similar to that of the work of art to reality. [...] Sociability has no objective purpose, no content, no extrinsic results, it entirely depends on the personalities among whom it occurs. Its aim is nothing but the success of the sociable moment and, at most, a memory of it. Hence the conditions and results of the process of sociability are exclusively the persons who find themselves at a social gathering. (G. Simmel, 1908) I thus designate sociability as the play-form of sociation. Its relation to content- determined, concrete sociation is similar to that of the work of art to reality. [...] Sociability has no objective purpose, no content, no extrinsic results, it entirely depends on the personalities among whom it occurs. Its aim is nothing but the success of the sociable moment and, at most, a memory of it. Hence the conditions and results of the process of sociability are exclusively the persons who find themselves at a social gathering. (G. Simmel, 1908)
  • LIPARI23/07/2014 DAVIDEBENNATO Barry Wellman: Networked individualism (2002) A community is a network of relationship in practice, societies and peoples lives are often mixtures of groups and networks Mark Lombardi: http://modcult.org/image/1976
  • LIPARI23/07/2014 DAVIDEBENNATO
  • LIPARI23/07/2014 DAVIDEBENNATO Little boxes (Wellman 2002) Pre-industrial social relationships were based on itinerant bands, agrarian villages, trading towns, and urban neighborhoods. People walked door-to-door to visit each other in spatially compact and densely-knit milieus. If most settlements or neighborhoods contained less than a thousand people, then almost everybody would know each other. Communities were bounded, so that most relationships happened within their gates rather than across them. Much interaction stayed within neighborhoods, even in big cities and trading towns. When people visited someone, most neighbors knew who was going to see whom and what their interaction was about. Contact was essentially between households, with the awareness, sanction and control of the settlement.
  • LIPARI23/07/2014 DAVIDEBENNATO Glocalized networks (Wellman 2002) If community is defined socially rather than spatially, then it is clear that contemporary communities rarely are limited to neighborhoods. They are communities of shared interest rather than communities of shared kinship or locality. People usually obtain support, companionship, information and a sense of belonging from those who do not live within the same neighborhood or even within the same metropolitan area. Many peoples work involves contact with shifting sets of people in other units, workplaces, and even other organizations. People maintain these ties through phoning, emailing, writing, driving, railroading, transiting, and flying
  • LIPARI23/07/2014 DAVIDEBENNATO Networked Individualism (Wellman 2002) We are now experiencing another transition, from place-to-place to person-to-person connectivity. Moving around with a mobile phone, pager, or wireless Internet makes people less dependent on place. Because connections are to people and not to places, the technology affords shifting of work and community ties from linking people-in-places to linking people wherever they are. It is I-alone that is reachable wherever I am: at a house, hotel, office, freeway or mall. The person has become the portal [] The shift to a personalized, wireless world affords networked individualism, with each person switching between ties and networks. People remain connected, but as individuals rather than being rooted in the home bases of work unit and household. Individuals switch rapidly between their social networks. Each person separately operates his networks to obtain information, collaboration, orders, support, sociability, and a sense of belonging
  • LIPARI23/07/2014 DAVIDEBENNATO COMMUNITY: SOCIOLOGICAL PROPERTIES
  • LIPARI23/07/2014 DAVIDEBENNATO People Little number Large number https://www.flickr.com/photos/jbid-post/6555965015/
  • LIPARI23/07/2014 DAVIDEBENNATO Relationship Strong: stable, everyday Weak: unstable, seldom https://www.flickr.com/photos/bunnyrel/8290653345/
  • LIPARI23/07/2014 DAVIDEBENNATO Social semantic Content based: e.g. Football fans Project based: e.g. activists Relationship based: e.g. friendship, brotherhood https://www.flickr.com/photos/paulisson_miura/14265444730/
  • LIPARI23/07/2014 DAVIDEBENNATO Time Permanent: e.g. family ties Temporary: e.g. media audience https://www.flickr.com/photos/adamendoza/3150313038/
  • LIPARI23/07/2014 DAVIDEBENNATO Place Physical: e.g. neighbourood Digital: e.g. social network connections Blurred: e.g. earthquake tweets https://www.flickr.com/photos/sierragoddess/5435989568/
  • LIPARI23/07/2014 DAVIDEBENNATO COMMUNITY: SOCIO-COMPUTATIONAL PROPERTIES
  • LIPARI23/07/2014 DAVIDEBENNATO Concept: Modularity Its a formalization of the idea that communities should contain many connection within and few outside of the group(Jrgens 2014)
  • LIPARI23/07/2014 DAVIDEBENNATO Concept: Clique A clique is a subset of points in which every possibile pair of points is directly connected by a line and the clique is not contained in any other clique (Scott 2000)
  • LIPARI23/07/2014 DAVIDEBENNATO Algorithm: Girvan and Newman (Jrgens 2014) Its based on betweenness centrality: how many shortest paths across the network lead through one link One by one the links through which the most short connections lead are removed http://www.chinaz.com/web/2012/1224/286875_2.shtml
  • LIPARI23/07/2014 DAVIDEBENNATO https://ultrabpm.wordpress.com/2013/03/25/social-network-analysis-part-two/
  • LIPARI23/07/2014 DAVIDEBENNATO Algorithm: clique percolation (Jrgens 2014) Networks can be said to have choke points that separate two well connected areas from each other. CP finds cliques where every node is connected to every other node and moves them across the network until they reach a choke point As the algorithm increases the size of cliques fewer and fewer communities exist http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.94.160202
  • LIPARI23/07/2014 DAVIDEBENNATO http://horicky.blogspot.it/2012/11/detecting-communities-in-social-graph.html
  • LIPARI23/07/2014 DAVIDEBENNATO COMMUNITY: CASE STUDY
  • LIPARI23/07/2014 DAVIDEBENNATO http://adequatebird.com/2010/05/03/the-political-blogosphere-and-the-2004-u-s-election-divided-they-blog/ Political blogosfere (Adamic, Glance 2005)
  • LIPARI23/07/2014 DAVIDEBENNATO http://inmaps.linkedinlabs.com/
  • LIPARI23/07/2014 DAVIDEBENNATO http://blog.socialflow.com/post/5246404319/breaking-bin-laden-visualizing-the-power-of-a-single
  • LIPARI23/07/2014 DAVIDEBENNATO
  • LIPARI23/07/2014 DAVIDEBENNATO Mapping Twitter T

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