%0 
%0 Conference Proceedings
%A Capocci, Andrea; Baldassarri, Andrea; Servedio, Vito D. P. & Loreto, Vittorio
%D 2010
%T Friendship, collaboration and semantics in Flickr: from social interaction to semantic similarity
%E 
%B MSM '10: Proceedings of the International Workshop on Modeling Social Media
%C New York, NY, USA
%I ACM
%V 
%6
%N 
%P 1--4
%& 
%Y 
%S 
%7
%8 
%9
%? 
%! 
%Z 
%@ 978-1-4503-0229-6
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%)
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%1 
%2 Friendship, collaboration and semantics in Flickr
%3 inproceedings
%4 
%# 
%$ 
%F capocci2010friendship
%K flickr, evidence_networks, semanitcs, user_interation, toread
%X We study the semantic assortativity in the social networks hosted by the Flickr folksonomy, based both on the contact data and on the group membership data provided by the users. The social network built this way are complex one. Besides, one observes a clear assortativity pattern, stronger than in a suitable null model adopted for a comparison. Nevertheless, such semantical similarity does not appear to develop during the community evolution, but is rather the result of a pre-existing shared background between users.
%Z 
%U http://portal.acm.org/citation.cfm?id=1835980.1835988
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Barrat, Alain; Baldassarri, Andrea; Schehr, Gregory & Loreto, Vittorio
%D 2009
%T Collective dynamics of social annotation
%E 
%B Proceedings of the National Academy of Sciences
%C 
%I 
%V 106
%6
%N 26
%P 10511-10515
%& 
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%2 Collective dynamics of social annotation
%3 article
%4 
%# 
%$ 
%F cattuto2009collective
%K tagging, toread_dbe
%X The enormous increase of popularity and use of the worldwide web has led in the recent years to important changes in the ways people communicate. An interesting example of this fact is provided by the now very popular social annotation systems, through which users annotate resources (such as web pages or digital photographs) with keywords known as “tags.” Understanding the rich emergent structures resulting from the uncoordinated actions of users calls for an interdisciplinary effort. In particular concepts borrowed from statistical physics, such as random walks (RWs), and complex networks theory, can effectively contribute to the mathematical modeling of social annotation systems. Here, we show that the process of social annotation can be seen as a collective but uncoordinated exploration of an underlying semantic space, pictured as a graph, through a series of RWs. This modeling framework reproduces several aspects, thus far unexplained, of social annotation, among which are the peculiar growth of the size of the vocabulary used by the community and its complex network structure that represents an externalization of semantic structures grounded in cognition and that are typically hard to access.
%Z 
%U http://www.pnas.org/content/106/26/10511.abstract
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Barrat, Alain; Baldassarri, Andrea; Schehr, Gregory & Loreto, Vittorio
%D 2009
%T Collective dynamics of social annotation
%E 
%B CoRR
%C 
%I 
%V abs/0902.2866
%6
%N 
%P 
%& 
%Y 
%S 
%7
%8 April
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%@ 
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%1 
%2 
%3 article
%4 
%# 
%$ 
%F cattuto2009collective
%K dynamics, folksonomy, bibsonomy
%X   The enormous increase of popularity and use of the WWW has led in the recent
years to important changes in the ways people communicate. An interesting
example of this fact is provided by the now very popular social annotation
systems, through which users annotate resources (such as web pages or digital
photographs) with text keywords dubbed tags. Understanding the rich emerging
structures resulting from the uncoordinated actions of users calls for an
interdisciplinary effort. In particular concepts borrowed from statistical
physics, such as random walks, and the complex networks framework, can
effectively contribute to the mathematical modeling of social annotation
systems. Here we show that the process of social annotation can be seen as a
collective but uncoordinated exploration of an underlying semantic space,
pictured as a graph, through a series of random walks. This modeling framework
reproduces several aspects, so far unexplained, of social annotation, among
which the peculiar growth of the size of the vocabulary used by the community
and its complex network structure that represents an externalization of
semantic structures grounded in cognition and typically hard to access.

%Z arxiv:0902.2866

%U http://arxiv.org/abs/0902.2866
%+
%^

%0 
%0 Conference Proceedings
%A Cattuto, Ciro; Baldassarri, Andrea; Servedio, Vito D. P. & Loreto, Vittorio
%D 2007
%T Emergent Community Structure in Social Tagging Systems
%E 
%B Proceedings of the European Confeence on Complex Systems
%C Dresden, Germany
%I 
%V 
%6
%N 
%P 
%& 
%Y 
%S 
%7
%8 October
%9
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%)
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%1 
%2 
%3 inproceedings
%4 
%# 
%$ 
%F cattuto2007emergent
%K folksonomies, clustering, community_detection
%X 
%Z 
%U 
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Schmitz, Christoph; Baldassarri, Andrea; Servedio, Vito D. P.; Loreto, Vittorio; Hotho, Andreas; Grahl, Miranda & Stumme, Gerd
%D 2007
%T Network Properties of Folksonomies
%E 
%B AI Communications Journal, Special Issue on ``Network Analysis in Natural Sciences and Engineering''
%C 
%I IOS Press
%V 20
%6
%N 4
%P 245-262
%& 
%Y 
%S 
%7
%8 
%9
%? 
%! 
%Z 
%@ 0921-7126
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%)
%*
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%1 
%2 
%3 article
%4 
%# 
%$ 
%F cattuto2007networkb
%K 2007, itegpub, folksonomies, tagorapub, l3s, folksonomy, emergent, fca, semantics, network, myown
%X 
%Z 
%U http://www.kde.cs.uni-kassel.de/stumme/papers/2007/cattuto2007network.pdf
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Schmitz, Christoph; Baldassarri, Andrea; Servedio, Vito D. P.; Loreto, Vittorio; Hotho, Andreas; Grahl, Miranda & Stumme, Gerd
%D 2007
%T Network Properties of Folksonomies
%E 
%B AI Communications Journal, Special Issue on ``Network Analysis in Natural Sciences and Engineering''
%C 
%I IOS Press
%V 20
%6
%N 4
%P 245-262
%& 
%Y 
%S 
%7
%8 
%9
%? 
%! 
%Z 
%@ 0921-7126
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%)
%*
%L
%M
%1 
%2 See http://www.bibsonomy.org/bibtex/2e1a5234a896b1f422473b1fe5d91e26b/stumme for a shorter workshop version.
%3 article
%4 
%# 
%$ 
%F cattuto2007networkb
%K 2007, itegpub, folksonomies, tagorapub, l3s, folksonomy, emergent, fca, semantics, network
%X 
%Z 
%U http://www.kde.cs.uni-kassel.de/stumme/papers/2007/cattuto2007network.pdf
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Schmitz, Christoph; Baldassarri, Andrea; Servedio, Vito D. P.; Loreto, Vittorio; Hotho, Andreas; Grahl, Miranda & Stumme, Gerd
%D 2007
%T Network properties of folksonomies
%E 
%B AI Communications
%C 
%I IOS Press
%V 20
%6
%N 4
%P 245--262
%& 
%Y 
%S 
%7
%8 December
%9
%? 
%! 
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%@ 0921-7126
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%)
%*
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%1 
%2 
%3 article
%4 
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%$ 
%F cattuto2007network
%K background, ol_web2.0, folksonomy, property, network, sna, emergentsemantics_evidence
%X Social resource sharing systems like YouTube and del.icio.us have acquired a large number of users within the last few years. They provide rich resources for data analysis, information retrieval, and knowledge discovery applications. A first step towards this end is to gain better insights into content and structure of these systems. In this paper, we will analyse the main network characteristics of two of these systems. We consider their underlying data structures - so-called folksonomies - as tri-partite hypergraphs, and adapt classical network measures like characteristic path length and clustering coefficient to them.Subsequently, we introduce a network of tag co-occurrence and investigate some of its statistical properties, focusing on correlations in node connectivity and pointing out features that reflect emergent semantics within the folksonomy. We show that simple statistical indicators unambiguously spot non-social behavior such as spam.
%Z 
%U http://portal.acm.org/citation.cfm?id=1365538
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Schmitz, Christoph; Baldassarri, Andrea; Servedio, Vito D. P.; Loreto, Vittorio; Hotho, Andreas; Grahl, Miranda & Stumme, Gerd
%D 2007
%T Network Properties of Folksonomies
%E 
%B AI Communications
%C 
%I IOS Press
%V 20
%6
%N 4
%P 245--262
%& 
%Y 
%S 
%7
%8 December
%9
%? 
%! 
%Z 
%@ 0921-7126
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%)
%*
%L
%M
%1 
%2 
%3 article
%4 
%# 
%$ 
%F cattuto2007network
%K ol_tut2010, social, analysis, folksonomy, property, network, sna
%X Social resource sharing systems like YouTube and del.icio.us have acquired a large number of users within the last few years. They provide rich resources for data analysis, information retrieval, and knowledge discovery applications. A first step towards this end is to gain better insights into content and structure of these systems. In this paper, we will analyse the main network characteristics of two of these systems. We consider their underlying data structures - so-called folksonomies - as tri-partite hypergraphs, and adapt classical network measures like characteristic path length and clustering coefficient to them.  Subsequently, we introduce a network of tag co-occurrence and investigate some of its statistical properties, focusing on correlations in node connectivity and pointing out features that reflect emergent semantics within the folksonomy. We show that simple statistical indicators unambiguously spot non-social behavior such as spam. 
%Z 
%U http://www.kde.cs.uni-kassel.de/pub/pdf/cattuto2007network.pdf
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Schmitz, Christoph; Baldassarri, Andrea; Servedio, Vito D. P.; Loreto, Vittorio; Hotho, Andreas; Grahl, Miranda & Stumme, Gerd
%D 2007
%T Network Properties of Folksonomies
%E 
%B AI Communications Journal, Special Issue on ``Network Analysis in Natural Sciences and Engineering''
%C 
%I IOS Press
%V 20
%6
%N 4
%P 245-262
%& 
%Y 
%S 
%7
%8 
%9
%? 
%! 
%Z 
%@ 0921-7126
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%)
%*
%L
%M
%1 
%2 Publications of Gerd Stumme
%3 article
%4 
%# 
%$ 
%F cattuto2007network
%K 2007, seminar2009, itegpub, folksonomies, tagorapub, l3s, folksonomy, emergent, fca, semantics, network, myown
%X 
%Z 
%U http://www.kde.cs.uni-kassel.de/stumme/papers/2007/cattuto2007network.pdf
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Schmitz, Christoph; Baldassarri, Andrea; Servedio, Vito D. P.; Loreto, Vittorio; Hotho, Andreas; Grahl, Miranda & Stumme, Gerd
%D 2007
%T Network Properties of Folksonomies
%E 
%B AI Communications Journal, Special Issue on ``Network Analysis in Natural Sciences and Engineering''
%C 
%I IOS Press
%V 20
%6
%N 4
%P 245-262
%& 
%Y 
%S 
%7
%8 
%9
%? 
%! 
%Z 
%@ 0921-7126
%(
%)
%*
%L
%M
%1 
%2 See http://www.bibsonomy.org/bibtex/2e1a5234a896b1f422473b1fe5d91e26b/stumme for a shorter workshop version.
%3 article
%4 
%# 
%$ 
%F cattuto2007network
%K BibSonomy, folksonomy, network, BibTeX
%X 
%Z 
%U http://www.kde.cs.uni-kassel.de/stumme/papers/2007/cattuto2007network.pdf
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Schmitz, Christoph; Baldassarri, Andrea; Servedio, Vito D. P.; Loreto, Vittorio; Hotho, Andreas; Grahl, Miranda & Stumme, Gerd
%D 2007
%T Network Properties of Folksonomies
%E 
%B AI Communications
%C 
%I 
%V 20
%6
%N 4
%P 245 - 262
%& 
%Y 
%S 
%7
%8 
%9
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%@ 
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%)
%*
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%1 
%2 
%3 article
%4 
%# 
%$ 
%F cattuto2007network
%K 2007, folksonomies, summerschool, network, myown, properties, sosbuch, kdubiq
%X 
%Z 
%U http://www.kde.cs.uni-kassel.de/hotho/pub/2007/aicomm_2007_folksonomy_clustering.pdf
%+
%^

%0 
%0 Conference Proceedings
%A Cattuto, Ciro; Baldassarri, Andrea; Servedio, Vito D. P. & Loreto, Vittorio
%D 2007
%T Vocabulary growth in collaborative tagging systems
%E 
%B 
%C 
%I 
%V 
%6
%N 
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%Y 
%S 
%7
%8 
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%1 
%2 Vocabulary growth in collaborative tagging systems
%3 inproceedings
%4 
%# 
%$ 
%F cattuto2007vocabulary
%K analysis, folksonomy, vocabulary, toread
%X  We analyze a large-scale snapshot of del.icio.us and investigate how the number of different tags in the system grows as a function of a suitably defined notion of time. We study the temporal evolution of the global vocabulary size, i.e. the number of distinct tags in the entire system, as well as the evolution of local vocabularies, that is the growth of the number of distinct tags used in the context of a given resource or user. In both cases, we find power-law behaviors with exponents smaller than one. Surprisingly, the observed growth behaviors are remarkably regular throughout the entire history of the system and across very different resources being bookmarked. Similar sub-linear laws of growth have been observed in written text, and this qualitative universality calls for an explanation and points in the direction of non-trivial cognitive processes in the complex interaction patterns characterizing collaborative tagging.
%Z 
%U http://www.citebase.org/abstract?id=oai:arXiv.org:0704.3316
%+
%^

%0 
%0 Journal Article
%A Cattuto, Ciro; Baldassarri, Andrea; Servedio, Vito Domenico Pietro & Loreto, Vittorio
%D 2007
%T Vocabulary growth in collaborative tagging systems
%E 
%B CoRR
%C 
%I 
%V abs/0704.3316
%6
%N 
%P 
%& 
%Y 
%S 
%7
%8 April
%9
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%)
%*
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%M
%1 
%2 dblp
%3 article
%4 
%# 
%$ 
%F cattuto2007growth
%K folksonomy, vocabulary, growth
%X We analyze a large-scale snapshot of del.icio.us and investigate how the number of different tags in the system grows as a function of a suitably defined notion of time. We study the temporal evolution of the global vocabulary size, i.e. the number of distinct tags in the entire system, as well as the evolution of local vocabularies, that is the growth of the number of distinct tags used in the context of a given resource or user. In both cases, we find power-law behaviors with exponents smaller than one. Surprisingly, the observed growth behaviors are remarkably regular throughout the entire history of the system and across very different resources being bookmarked. Similar sub-linear laws of growth have been observed in written text, and this qualitative universality calls for an explanation and points in the direction of non-trivial cognitive processes in the complex interaction patterns characterizing collaborative tagging. 
%Z arXiv:0704.3316v1
%U http://arxiv.org/abs/0704.3316
%+
%^

%0 
%0 Generic
%A Cattuto, Ciro; Baldassarri, Andrea; Servedio, Vito D. P. & Loreto, Vittorio
%D 2007
%T Vocabulary growth in collaborative tagging systems
%E
%B 
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%1 
%2 Vocabulary growth in collaborative tagging systems
%3 misc
%4 
%# 
%$ 
%F cattuto-2007
%K systems, tagging, taggingsurvey, 2.0, collaborative, vocabulary, web
%X 
%Z 
%U http://www.citebase.org/abstract?id=oai:arXiv.org:0704.3316
%+
%^

%0 
%0 Conference Proceedings
%A Schmitz, Christoph; Grahl, Miranda; Hotho, Andreas; Stumme, Gerd; Catutto, Ciro; Baldassarri, Andrea; Loreto, Vittorio & Servedio, Vito D. P.
%D 2007
%T Network Properties of Folksonomies
%E 
%B Proc. WWW2007 Workshop ``Tagging and Metadata for Social Information Organization''
%C Banff
%I 
%V 
%6
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%8 May
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%4 
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%$ 
%F schmitz07network
%K 2007, itegpub, socialnetwork, smallworld, l3s, folksonomy, emergent, fca, semantics, myown, folksononomies, sna
%X 
%Z 
%U http://www.kde.cs.uni-kassel.de/stumme/papers/2007/schmitz07network.pdf
%+
%^

%0 
%0 Conference Proceedings
%A Schmitz, Christoph; Grahl, Miranda; Hotho, Andreas; Stumme, Gerd; Catutto, Ciro; Baldassarri, Andrea; Loreto, Vittorio & Servedio, Vito D. P.
%D 2007
%T Network Properties of Folksonomies
%E 
%B Proc. WWW2007 Workshop ``Tagging and Metadata for Social Information Organization''
%C Banff
%I 
%V 
%6
%N 
%P 
%& 
%Y 
%S 
%7
%8 May
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%2 Publications of Gerd Stumme
%3 inproceedings
%4 
%# 
%$ 
%F schmitz07network
%K 2007, itegpub, socialnetwork, smallworld, l3s, folksonomy, emergent, fca, semantics, myown, folksononomies, sna
%X 
%Z 
%U http://www.kde.cs.uni-kassel.de/stumme/papers/2007/schmitz07network.pdf
%+
%^

%0 
%0 Conference Proceedings
%A Schmitz, Christoph; Grahl, Miranda; Hotho, Andreas; Stumme, Gerd; Catutto, Ciro; Baldassarri, Andrea; Loreto, Vittorio & Servedio, Vito D. P.
%D 2007
%T Network Properties of Folksonomies
%E 
%B Proc. WWW2007 Workshop ``Tagging and Metadata for Social Information Organization''
%C Banff
%I 
%V 
%6
%N 
%P 
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%4 
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%F schmitz2007network
%K 2007, workshop, folksonomy, network, myown, sna
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%U 
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