Introductory Social Network Analysis with PajekOverview of Network Analysis ToolsTools We’ll Use in this CourseOther Tools: gephiOther Visualization Tools: WalrusVisualization Tool: GraphVizDot (GraphViz)Visualization Tools: YEd - JavaTM Graph Editor http://www.yworks.com/en/products_yed_about.htm (good primarily for layouts, scales better, maybe free)yEd and 26,000 Nodes (Takes a Few Seconds)Visualization Tools: PrefuseSimple Prefuse VisualizationsPrefuse Application: Flow MapsPrefuse Application: VizsterVisualization Tool: ManyeyesOutlineUsing Pajek for Exploratory Social Network AnalysisPajek: InterfacePajek: Opening a Network FilePajek: Working with Network FilesPajek data formatPajek: Let’s Get StartedPajek: Opening a FilePajek: Visualization & Manual PositioningPajek: Visualization & Layout AlgorithmsA Directed NetworkNode Centrality: DegreeCentrality: DegreeConnected ComponentsThe bowtie model of the Web Broder et al. (1999)Let’s try this on the dining table partnersSnowball SamplingBipartite networksGoing from a Bipartite to a One-mode GraphLet’s Try it on the Actors NetworkActors Network (continued)Slide 36Grabbing Your Data from Facebook via NexusPajek: Wrap Up2009 © University of Michigan1Introductory Social Network Analysiswith Pajek(Lecture for SI508 Networks: Theory and Application) Sept 16, 2009Instructor: Qiaozhu MeiSchool of InformationUniversity of Michigan2009 © University of MichiganOverview of Network Analysis ToolsPajeknetwork analysis and visualization,menu driven, suitable for large networks platforms: Windows (on linux via Wine) downloadNetlogoagent based modelingrecently added network modeling capabilities platforms: any (Java)download GUESSnetwork analysis and visualization,extensible, script-driven (jython) platforms: any (Java)downloadOther software tools that we will not be using but that you may find useful: visualization and analysis: UCInet - user friendly social network visualization and analysis software (suitable smaller networks)iGraph - if you are familiar with R, you can use iGraph as a module to analyze or create large networks, or you can directly use the C functions Jung - comprehensive Java library of network analysis, creation and visualization routinesGraph package for Matlab (untested?) - if Matlab is the environment you are most comfortable in, here are some basic routines SIENA - for p* models and longitudinal analysis SNA package for R - all sorts of analysis + heavy duty stats to boot NetworkX - python based free package for analysis of large graphsInfoVis Cyberinfrastructure - large agglomeration of network analysis tools/routines, partly menu driven visualization only:GraphViz - open source network visualization software (can handle large/specialized networks)TouchGraph - need to quickly create an interactive visualization for the web? yEd - free, graph visualization and editing software specialized:fast community finding algorithmmotif profilesCLAIR library - NLP and IR library (Perl Based) includes network analysis routines finally: INSNA long list of SNA packages2009 © University of MichiganTools We’ll Use in this Course•Pajek: extensive menu-driven functionality, including many, many network metrics and manipulations–but… not extensible•Guess: extensible, scriptable tool of exploratory data analysis, but more limited selection of built-in methods compared to Pajek•NetLogo: general agent based simulation platform with excellent network modeling support–many of the demos in this course were built with NetLogo•NetDraw: network visualization tool associated with UCInet. UCInet is not free, but NetDraw is.2009 © University of MichiganOther Tools: gephi•http://gephi.org•primarily for visualization, has some nice touches2009 © University of MichiganOther Visualization Tools: Walrus•developed at CAIDA available under the GNU GPL. •“…best suited to visualizing moderately sized graphs that are nearly trees. A graph with a few hundred thousand nodes and only a slightly greater number of links is likely to be comfortable to work with.”•Java-based•Implemented Features–rendering at a guaranteed frame rate regardless of graph size–coloring nodes and links with a fixed color, or by RGB values stored in attributes–labeling nodes–picking nodes to examine attribute values–generating subgraph: displaying a subset of nodes or links based on a user-supplied boolean attribute–interactive pruning of the graph to temporarily reduce clutter and occlusion–zooming in and outSource: CAIDA, http://www.caida.org/tools/visualization/walrus/2009 © University of MichiganVisualization Tool: GraphViz•Takes descriptions of graphs in simple text languages•Outputs images in useful formats•Options for shapes and colors•Standalone or use as a library•dot: hierarchical or layered drawings of directed graphs, by avoiding edge crossings and reducing edge length•neato (Kamada-Kawai) and fdp (Fruchterman-Reinhold with heuristics to handle larger graphs)•twopi – radial layout•circo – circular layouthttp://www.graphviz.org/2009 © University of MichiganDot (GraphViz)2009 © University of MichiganVisualization Tools: YEd - JavaTM Graph Editorhttp://www.yworks.com/en/products_yed_about.htm(good primarily for layouts, scales better, maybe free)2009 © University of MichiganyEd and 26,000 Nodes (Takes a Few Seconds)2009 © University of MichiganVisualization Tools: Prefuse•(free) user interface toolkit for interactive information visualization –built in Java using Java2D graphics library –data structures and algorithms –pipeline architecture featuring reusable, composable modules –animation and rendering support –architectural techniques for scalability •requires knowledge of Java programming•website: http://prefuse.sourceforge.net/–CHI paper http://guir.berkeley.edu/pubs/chi2005/prefuse.pdf2009 © University of MichiganSimple Prefuse VisualizationsSource: Prefuse, http://prefuse.sourceforge.net/2009 © University of MichiganPrefuse Application: Flow MapsA flow map of migration from California from 1995-2000, generated automatically by Prefuse system using edge routing but no layout adjustment. http://graphics.stanford.edu/papers/flow_map_layout/2009 © University of MichiganPrefuse Application: Vizsterhttp://jheer.org/vizster/2009 © University of MichiganVisualization Tool: Manyeyes•http://manyeyes.alphaworks.ibm.com/manyeyes/•Only for Visualization•Not just for