1. CMU SCS Panel: Social Networks Christos Faloutsos CMU

2. CMU SCS KDD panel 2008C. Faloutsos 2 Successes surprising patterns (older: 6 degrees; weak ties) power laws small/shrinking diameters navigability; ‘web as a bow tie’ influence curves ~ sigmoid

3. CMU SCS KDD panel 2008C. Faloutsos 3 Successes – cont’ed Great tools graph partitioning – community detection [spectral, METIS, co-clustering, etc] frequent subgraphs and graph indexing [Han+, Zaki+, Karypis+,...] node proximity [Volinsky/Coren; Tong+;...] connection subgraphs [Tomkins+], CePS, G-ray [Tong+] tensors [Kolda+, Sun+,...]

4. CMU SCS KDD panel 2008C. Faloutsos 4 Successes - cont’d Impact better predictions (eg., [Hill, Provost, Volinsky: ‘Network-based marketing’], [Jensen & Neville]); fraud detection ([Chau+, Sun+,... ]) recommendation systems (Amazon, Netflix,...) blog analysis [Tomkins+]; cascades

5. CMU SCS KDD panel 2008C. Faloutsos 5 Non-technical Obstacles Many interesting datasets are ‘secret’ –but data owners often provide access under NDA Privacy concerns

6. CMU SCS KDD panel 2008C. Faloutsos 6 Opportunities Companies/government WANT to analyze their data, and usually they welcome any help Collecting/crawling data is easier than ever HW continues getting cheaper/faster/better (1Tb disk ~ USD200)

7. CMU SCS KDD panel 2008C. Faloutsos 7 Technical Challenges High level: Scalability: Petabytes of data [Fayyad’07] cross-disciplinarity (CS + Econ + Soc +...)

8. CMU SCS KDD panel 2008C. Faloutsos 8 Technical Challenges – cont’d Grand challenge: ‘theory of everything’: how real SN are generated, how they evolve, how rumors/opinions propagate in them how often humans build/drop links...

9. CMU SCS KDD panel 2008C. Faloutsos 9 Conclusion Scalability – map/reduce and hadoop Cross-disciplinarity: give and take tools to/from: –databases and operating systems –game theory (‘incentives’) –linear algebra (SVD, tensors, etc) –other network settings (computer networks, protein-protein interaction networks, etc)

10. CMU SCS KDD panel 2008C. Faloutsos 10 Contact info: www. cs.cmu.edu /~christos Thank you!