Research Scientist

Complex Networks Lagrange Lab

Institute for Scientific Interchange (ISI) 

Torino (Italy)

                               

 Recent papers
                                

  • The paper Community detection in graphs (Eprint arXiv: 0906.0612) is the first comprehensive review article on the problem of graph clustering, which consists in identifying clusters of vertices with a high internal density of edges, whereas the density of edges between clusters is comparatively low.
  • The paper Statistical physics of social dynamics (Rev. Mod. Phys. 81, 591-646, 2009) is the first exhaustive review article of the growing field of sociophysics, where complex large-scale social phenomena are described by means of tools and techniques from statistical physics.
  • In the paper Detecting the overlapping and hierarchical community structure in complex networks (New J. Phys. 11, 033015, 2009) we propose the first method to detect both the hierarchy among the communities and possible overlaps between communities. The method relies on the local optimization of a fitness function.
  • Is physics more important than biology? In the paper Universality of citation distributions: toward an objective measure of scientific impact (Proc. Natl. Acad. Sci. USA 105, 17268-17272, 2008) we show that the distribution of the number of citations received by a paper, once suitably normalized, is the same in all scientific disciplines, opening the way to a possible objective evaluation of the impact of papers and authors. Read the feature of Philip Ball on Nature News!
  • In the paper Benchmark graphs for testing community detection algorithms (Phys. Rev. E 78, 046110, 2008) we present a new class of graphs for testing algorithms to find communities in networks. The new graphs are characterized by skewed distributions for the node degrees and the community sizes, which are important features of real graphs, neglected by current benchmarks. A software package to build the graphs can be downloaded here.
  • In the paper Complex networks renormalization: flows and fixed points (Phys. Rev. Lett. 101, 148701, 2008) we study how graphs transform under repeated box-covering transformations. We find that the topological variables display scaling behavior with critical exponents like in the standard renormalization in statistical mechanics. Featured by Physics!
  • How do users navigate on the Web? In the paper Ranking Web sites with real user traffic (Proc. WSDM 2008, Stanford, CA, USA) we study the traffic patterns of Web users, finding strong regularities. The data about traffic are also used to validate the PageRank model, whose underlying hypotheses turn out to be  violated.
  • Do voters behave like particles?  In the paper Scaling and universality in proportional elections (Phys. Rev. Lett. 99, 138701, 2007), we show that the distribution of the number of votes among candidates is the same in different  countries and years. Here you can see the universal election curve!