TY - GEN AU - Ghoshal, Gourab AU - Zlatic, Vinko AU - Caldarelli, Guido AU - Newman, M. E. J. A2 - T1 - Random hypergraphs and their applications JO - PB - AD - PY - 2009/ VL - IS - SP - EP - UR - http://arxiv.org/abs/0903.0419 M3 - KW - newman KW - hypergraph KW - random KW - random_graph KW - toread L1 - N1 - Random hypergraphs and their applications N1 - AB - In the last few years we have witnessed the emergence, primarily in on-linecommunities, of new types of social networks that require for theirrepresentation more complex graph structures than have been employed in thepast. One example is the folksonomy, a tripartite structure of users,resources, and tags -- labels collaboratively applied by the users to theresources in order to impart meaningful structure on an otherwiseundifferentiated database. Here we propose a mathematical model of suchtripartite structures which represents them as random hypergraphs. We show thatit is possible to calculate many properties of this model exactly in the limitof large network size and we compare the results against observations of a realfolksonomy, that of the on-line photography web site Flickr. We show that insome cases the model matches the properties of the observed network well, whilein others there are significant differences, which we find to be attributableto the practice of multiple tagging, i.e., the application by a single user ofmany tags to one resource, or one tag to many resources. ER - TY - GEN AU - Zlatic, Vinko AU - Ghoshal, Gourab AU - Caldarelli, Guido A2 - T1 - Hypergraph topological quantities for tagged social networks JO - PB - AD - PY - 2009/ VL - IS - SP - EP - UR - http://arxiv.org/abs/0905.0976 M3 - KW - folksonomies KW - analysis KW - hypergraph L1 - N1 - Hypergraph topological quantities for tagged social networks N1 - AB - Recent years have witnessed the emergence of a new class of social networks, that require us to move beyond previously employed representations of complex graph structures. A notable example is that of the folksonomy, an online process where users collaboratively employ tags to resources to impart structure to an otherwise undifferentiated database. In a recent paper[1] we proposed a mathematical model that represents these structures as tripartite hypergraphs and defined basic topological quantities of interest. In this paper we extend our model by defining additional quantities such as edge distributions, vertex similarity and correlations as well as clustering. We then empirically measure these quantities on two real life folksonomies, the popular online photo sharing site Flickr and the bookmarking site CiteULike. We find that these systems share similar qualitative features with the majority of complex networks that have been previously studied. We propose that the quantities and methodology described here can be used as a standard tool in measuring the structure of tagged networks. ER - TY - JOUR AU - Capocci, Andrea AU - Caldarelli, Guido T1 - Folksonomies and clustering in the collaborative system CiteULike JO - Journal of Physics A: Mathematical and Theoretical PY - 2008/ VL - 41 IS - 22 SP - EP - UR - http://stacks.iop.org/1751-8121/41/224016 M3 - KW - citeulike KW - *** KW - dataset KW - clustering KW - folksonomy KW - network KW - properties L1 - SN - N1 - N1 - AB - We analyze CiteULike, an online collaborative tagging system where users bookmark and annotate scientific papers. Such a system can be naturally represented as a tri-partite graph whose nodes represent papers, users and tags connected by individual tag assignments. The semantics of tags is studied here, in order to uncover the hidden relationships between tags. We find that the clustering coefficient can be used to analyze the semantical patterns among tags. ER - TY - JOUR AU - Capocci, Andrea AU - Servedio, Vito Domenico Pietro AU - Colaiori, Francesca AU - Buriol, Luciana S. AU - Donato, Debora AU - Leonardi, Stefano AU - Caldarelli, Guido T1 - Preferential attachment in the growth of social networks: the case of Wikipedia JO - CoRR PY - 2006/ VL - abs/physics/0602026 IS - SP - EP - UR - http://dblp.uni-trier.de/db/journals/corr/corr0602.html#abs-physics-0602026 M3 - KW - summerschool KW - social KW - network KW - sna KW - kdubiq KW - wikipedia L1 - SN - N1 - N1 - AB - ER -