Sébastien Heymann <seb@gephi.org>
Exploratory Network Analysis 1 see the network 1st graph viz tool: Pajek (1996) Vladimir Batagelj, Andrej Mrvar 2 interact in real time Gephi prototype (2008) group, filter, compute metrics... 3 build a visual language size by rank, color by partition, label, curved edges, thickness...
Looking for Orderness in Data Make varying 3 cursors simultaneously to extract meaningful patterns (statistical and structural properties) MICRO level MACRO level at different levels 1 dimension N dimensions on multiple dimensions T+0 T+N at time scale
Zoom cursor on Quantitative Data MICRO level MACRO level Global - connectivity - density - centralization Local - communities - bridges between communities - local centers vs periphery Individual - centrality - distances - neighborhood - location - local authority vs hub
Crossing cursor on Qualitative Data 1 dimension N dimensions Social - who with whom - communities - brokerage - influence and power - homophily Semantic - topics - thematic clusters Geographic - spatial phenomena
Timeline cursor on Temporal Data T+0 T+N Evolution of social ties Evolution of communities Evolution of topics
Mapping an Innovation Center Collaborations on projects at Images et Réseaux Themes and content Actors Territory Franck Ghitalla & Ecole de Design de Nantes
Gephi in a Nutshell «Like Photoshop for graphs.» Helps data analysts to reveal patterns and trends, highlight outliers and tells story with their data. Network visualization platform Open source, supported by a community Built for performance and usability Extensible by plug-ins Windows, MacOS X, Linux
Gephi Community Nonprofit organization Communities Contributors Mathieu Bastian, Mathieu Jacomy, Eduardo Ramos Ibañez, Sébastien Heymann, Guillaume Ceccarelli, André Panisson, Antonio Patriarca, Cezary Bartosiak, Martin Škurla, Patrick McSweeney, Yi Du, Hélder Suzuki, Daniel Bernardes, Ernesto Aneiro, Keheliya Gallaba, Luiz Ribeiro, Urban Škudnik, Vojtech Bardiovsky, Yudi Xue
Community Mission Provide a sustainable software Maintain the technical ecosystem Build a business ecosystem Face cutting-edge technological challenges with a long-term vision Distribute the software in Open Source
Community Values Open innovation: ideas and features come from the entire community. Decisions are taken with transparency. We consider this technology as a public good, and will keep it in open source.
Diversity of Usages business leisure :-) communication academic art
Diversity of Network Encoding V = { a, b, c, d, e } E = { (a,b), (a,d), (b,c), (e,a), (c,e) } Textual a b c d e a - 1-1 - b - - 1 - - c - - - - 1 d - - - - - e 1 - - - - Tabular Graphical <graph> <nodes> <node id= a /> <node id= b /> <node id= c /> <node id= d /> <node id= e /> </nodes> <edges> <edge source= a target= b /> <edge source= a target= d /> <edge source= b target= c /> <edge source= e target= a /> <edge source= c target= e /> </edges> </graph> XML and many others...
Software I/O MySQL PostgreSL SQL Server Neo4j databases user input file } > Excel Spreadsheet CSV Pajek NET Guess GDF GEXF GraphML Graphviz DOT UCInet DL NetdrawVNA Tulip TLP CSV Pajek NET Guess GDF GEXF GraphML file Excel Spreadsheet SVG PDF PNG graph streaming
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Gephi et la dynamique des graphes de terrain : technologie et applications Sébastien Heymann ISCN Journée Réseaux Dynamiques 24 mai 2012
Concepts
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Notions de dynamique En général, les logiciels implémentent la notion de snapshot : l état du graphe à différents instants. Exemple : Stanford SoNIA (Skye Bender-deMoll and McFarland, Daniel A. (2006) The Art and Science of Dynamic Network Visualization. Journal of Social Structure. Volume 7, Number 2) Sébastien Heymann Gephi Dynamics 24 mai 2012 3/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Notions de dynamique dans Gephi pas de notion de snapshot mais durée de vie des nœuds, liens et attributs (repris de SoNIA) Sébastien Heymann Gephi Dynamics 24 mai 2012 4/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Intervalle temporel Sébastien Heymann Gephi Dynamics 24 mai 2012 5/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Fenêtre glissante 0 1 2 3 TICKS WINDOW 0 1 2 3 4 5 6 TIME TIMELINE INTERVAL 0 1 2 3 TICKS WINDOW 0 1 2 3 4 5 6 TIME TIMELINE INTERVAL Sébastien Heymann Gephi Dynamics 24 mai 2012 6/24
Technologie
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Gephi : architecture modulaire Distribution : application stand-alone ou lib Java (Gephi Toolkit) Sébastien Heymann Gephi Dynamics 24 mai 2012 8/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Netbeans Platform The NetBeans Platform is a generic framework for Swing applications. It provides the plumbing that, before, every developer had to write themselves Sébastien Heymann Gephi Dynamics 24 mai 2012 9/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Gephi : modules Sébastien Heymann Gephi Dynamics 24 mai 2012 10/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Dynamic API API dedicated to dynamic network states and events. Browsing dynamic networks uses the Timeline component and defines a visible interval (i.e. a sub-graph). This API is responsible for holding and modifying that value. Retrieve/Set the current visible interval Get the current time format (date, double, datetime) Create DynamicGraph, a utility class to apply a sliding window on a dynamic graph. Sébastien Heymann Gephi Dynamics 24 mai 2012 11/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Statistiques dynamiques sélection de la taille de fenêtre temporelle sélection du pas de progression # nœuds, # liens, degré, coefficient de clustering Sébastien Heymann Gephi Dynamics 24 mai 2012 12/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Timeline Sébastien Heymann Gephi Dynamics 24 mai 2012 13/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Animation de la Timeline Sébastien Heymann Gephi Dynamics 24 mai 2012 14/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Sparklines et intervalles de présence pour les attributs dynamiques Présence, couleur et taille des éléments mis à jour en temps réel dans la visualisation. Sébastien Heymann Gephi Dynamics 24 mai 2012 15/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Import de données Feuille Excel avec colonnes start et end Base de données avec colonnes start et end Fichier de graphe au format GEXF Flux d événements via Graph Streaming API Sébastien Heymann Gephi Dynamics 24 mai 2012 16/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 GEXF GEXF est un format XML Standard porté par Gephi Spécifications commencées en 2007, version stable Dec. 2010 Topologie, attributs, hiérarchie, phylogénie, dynamique (intervalle ouvert/fermé, périodes) Extensible via des namespaces Sébastien Heymann Gephi Dynamics 24 mai 2012 17/24
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Flux d événements Repris de GraphStream (interopérabilité?) + format JSON : an : Add node cn : Change node dn : Delete node ae : Add edge ce : Change edge de : Delete edge Exemple : add node A { an :{ A :{ label : Streaming Node A, size :2}}} Sébastien Heymann Gephi Dynamics 24 mai 2012 18/24
Démo de Gephi Réseau de contact à Hypertext 2009 durée 2,5 jours Source : Sociopatterns.org
Applications
c n r s - u p m c l a b o r a t o i r e d i n f o r m a t i q u e d e p a r i s 6 Applications Exploration de la blogosphère Réseaux de contact (SocioPatterns.org/datasets) Fouille de documents (Quid, Inc.) Visualisation de Twitter (RT or #, e.g. the Royal Wedding) Crawl temps réel Autres (e.g. iso-octane dynamic selection, source code evolution) Sébastien Heymann Gephi Dynamics 24 mai 2012 21/24
cnrs - upmc laboratoire d informatique de paris 6 Face-to-face contacts Projet SocioPatterns.org (avec Alain Barrat, Ciro Cattuto...) J. Stehle et al. High-Resolution Measurements of Face-to-Face Contact Patterns in a Primary School. PLoS ONE 6(8) : e23176 Network of contacts aggregated over the first day. Se bastien Heymann Gephi Dynamics 24 mai 2012 22/24
Questions?
Merci! <seb@gephi.org>