Exploring Social Networks with Matrix-Based Representations

1. Exploring Social Networks with Matrix-Based Representations Nathalie Henry* & Jean-Daniel Fekete IN|SITU / AVIZ Lab. INRIA / Laboratoire de Recherche en Informatique *Université de Sydney Nathalie.Henry@lri.fr, Jean-Daniel.Fekete@inria.fr

2. The problem Using Node-Link diagrams to visualize: • Tree-like • Small-world • Almost-complete http://www.infovis-wiki.net/index.php/Social_Network_Generation Nathalie Henry Exploring Social Networks with Matrix-Based Representations

3. What social scientists are looking for • What are the communities? • How actors are linked within the community? • How communities are linked? • Who is central? Nathalie Henry Exploring Social Networks with Matrix-Based Representations

4. Proposing a readable representation for dense graphs • What are the communities? • How actors are linked within the community? • How communities are linked? • Who is central? ? [Ghoniem et al. 05] Nathalie Henry Exploring Social Networks with Matrix-Based Representations

5. Matrix Visualization ? ? Nathalie Henry Exploring Social Networks with Matrix-Based Representations

6. Usable without reordering No node overlapping No edge crossing Readable for dense graphs Fast navigation Fast manipulation Usable interactively More readable for some tasks Less intuitive Use more space Weak for path following tasks Intuitive Compact More readable for path following More effective for small graphs More effective for sparse graphs Useless without layout Node overlapping Edge crossing Not readable for dense graphs Manipulation requires layout computation Matrix vs NodeLink + - Nathalie Henry Exploring Social Networks with Matrix-Based Representations

7. Communicate Explore Nathalie Henry Exploring Social Networks with Matrix-Based Representations

8. Observation Evaluation Brainstorming Prototyping Participatory Design • What Social Science researchers • Use? (representations, software) • Analyze? (datasets) • Do? (tasks, exploration process) • Want? (aspiration) http://insitu.lri.fr/~nhenry/Workshop.html Nathalie Henry Exploring Social Networks with Matrix-Based Representations

9. Needs expressed for an exploratory analysis system • Multiple representations • Interaction… instead of parameter tuning [Henry&Fekete06] • Overviews • Connected Components Representation • Global Information on Graph and Social Networks • Data, Attributes, SNA: actors, relationship, degree distribution, diameter, 5 most connected, 5 less connected, centrality measures. • Multiples représentations: Nœuds-liens (moreno30’s), Matrices (forsyth40’s) • Layout for node-link, ordering for matrices • Interactions directly on the network • Filtering, Clustering (multiples), Aggregation • Compare, Confront, Annotate Nathalie Henry Exploring Social Networks with Matrix-Based Representations

10. Improve one representation Combine both representations Augment one representation Find hybrid representations Find other representations Better layout/ordering MatrixExplorer MatLink NodeTrix TreePlus, Links over Treemap, NetLens, Semantic Substrates… Possible solutions Nathalie Henry Exploring Social Networks with Matrix-Based Representations

11. 1. Improve one representation Layout (Node-Link) Order (Matrix)

12. Reorder to understand Bertin, 1967 • Why? • Survey in progress • Interactive techniques • Algorithms for reordering tables • Algorithms for graphs linearization Nathalie Henry Exploring Social Networks with Matrix-Based Representations

13. Identifying Visual Patterns Nathalie Henry Exploring Social Networks with Matrix-Based Representations

14. 2. Combine both representations MatrixExplorer

15. MatrixExplorer [Henry&Fekete06] • Matrices to explore • Node-Link diagrams to present findings Nathalie Henry Exploring Social Networks with Matrix-Based Representations

16. 3. Augment one representation MatLink

17. MatLink[Henry&Fekete07] • Solving the path-related tasks problem for matrices • Augmenting matrices with interactive links Nathalie Henry Exploring Social Networks with Matrix-Based Representations

18. Controlled experiment 3 vis. x 6 datasets x 5 tasks Matrix , Node-Link, MatLink Data: From almost-trees To complete-graphs Including small-world networks Tasks: 1. CommonNeighbour, 2. ShortestPath, 3. MostConnected, 4. ArticulationPoint, 5. LargestClique MatLink: significantly improving matrices Nathalie Henry Exploring Social Networks with Matrix-Based Representations

19. 4. Find a hybrid representation NodeTrix

20. NodeTrix[Henry et al.07] • Designed for small-world networks • Globally sparse • Locally dense • Visualizing dense sub-graphs as matrices • Interact to create, edit and remove the matrices Nathalie Henry Exploring Social Networks with Matrix-Based Representations

21. NodeTrix VIDEO at http://insitu.lri.fr/~nhenry/nodetrix/nodetrix.mov Nathalie Henry Exploring Social Networks with Matrix-Based Representations

22. NodeTrix: the NetVis Nirvana?  Can you see every node? Can you count each node’s degree? Can follow every link from its source to its destination? Can you idenfity clusters and outliers? • Node Labels • Link Labels (excentric labels?!) • … even clusters labels • Node Attributes • Link Attributes • … even clusters attributes • Directed Graph (links width?!) … But… It’s gonna be crowded here !    Nathalie Henry Exploring Social Networks with Matrix-Based Representations

23. Visual Patterns Cross Pattern Block Pattern Mixte Pattern Nathalie Henry Exploring Social Networks with Matrix-Based Representations

24. Visual Patterns Infovis Coauthorship (133 actors) Nathalie Henry Exploring Social Networks with Matrix-Based Representations

25. Using Interaction for Story-telling Nathalie Henry Exploring Social Networks with Matrix-Based Representations

26. Future Directions • Scaling up to very large network... …the problem of reordering • Provide usable tools to sociologists... …the problem of bug fixing • Navigating and aggregating [Zame] • Towards collaborative exploration • From exploration to story telling Nathalie Henry Exploring Social Networks with Matrix-Based Representations

27. La Fin

28. References • N. Henry, J-D. Fekete, M. Mcguffin. NodeTrix: Hybrid Representation for Analyzing Social Networks, Research Report 6183, INRIA, 2007. https://hal.inria.fr/inria-00144496 • N. Henry and J-D. Fekete. MatLink: Enhanced Matrix Visualization for Analyzing Social Networks. In Processding of the eleventh IFIP TC13 International Conference on Human-Computer Interaction (Interact 2007), September 2007. Springer Verlag. 14 pages, to be published. • N. Henry and J-D. Fekete. MatrixExplorer: a Dual-Representation System to Explore Social Networks. IEEE Transactions on Visualization and Computer Graphics (Proceedings Visualization / Information Visualization 2006), 12(5):677-684, September-October 2006. • M. Ghoniem, J-D. Fekete and P. Castagliola. Readability of Graphs Using Node-Link and Matrix-Based Representations: Controlled Experiment and Statistical Analysis. Information Visualization Journal, 4(2):114–135, 2005. Nathalie Henry Exploring Social Networks with Matrix-Based Representations