Sandia National Laboratories
Ali Pinar
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I work on various applications that involve graphs. Recently I have been working on modeling large scale graphs such as those of social networks, cyber networks. I have been also looking at power systems with focus on vulnerability analysis , and resilient network design. My early work was on traditional applications of combinatorial scientific computing such as sparse matrix computations and parallel computing, where the combinatorial algorithms work on the back stage to play an enabling role. Recently, I have started looking at areas where combinatorial problems are directly associated with scientific and engineering goals.

Before joining Sandia, I worked at Lawrence Berkeley National Laboratory between Oct 2001 and Oct 2008. And before that I received my PhD. in Computer science with the option of computational science and engineering from University of Illinois at Urbana Champaign (1997--2001), my M.S. and B.S. in Computer Science from Bilkent University, Turkey, in 1994 and 1996, respectively.

For more information about my work, you can look at my CV ...

Recent Activities

Recent Publications

Modeling and Analysis of Graphs

  • E. Sariyuce, C. Seshadhri, A. Pinar, and U. Catalyurek,Finding Overlapping and Hierarchical Dense Subgraphs using Nuclear Decompositions, arXiv:1411.3312
  • S. Soundarajan, T. Eliassi-Rad B. Gallagher, and A. Pinar, Strategies for Probing Incomplete Graphs, 2014.
  • M. Jha, A. Pinar, and C. Seshadhri, Path Sampling: A Fast and Provable Method for Estimating 4-Vertex Subgraph Counts, arXiv:1411.4942
  • M. Jha, C. Seshadhri, and A. Pinar, Counting Triangles in Real-World Graph Streams: Dealing with Repeated Edges and Time Windows, arXiv:1310:7665
  • C. Seshadhri, A. Pinar, N. Durak, and T. Kolda, Directed closure measures for networks with reciprocity, arXiv:1302:6220
  • C. Peng, T. Kolda, and A. Pinar, Accelerating Community Detection by Using k-core subgraphs, arXiv:1403.2226
  • M. Jha, C. Seshadhri, and A. Pinar, A space efficient streaming algorithm for estimating transitivity and triangle counts using the birthday paradox, to ap- pear in ACM Transactions on Knowledge Discovery from Data, also available as arXiv:1212.2264.
  • J. Ray, A. Pinar, and C. Seshadhri, A stopping criterion for Markov chains when generating independent random graphs, to appear in Journal of Compex Networks, preprint available as arXiv:1210.8184.
  • C. Seshadhri, A. Pinar, and T. Kolda, Wedge Sampling for Computing Clustering Coefficients and Triangle Counts on Large Graphs, in Statistical Analysis and Data Mining special issue for Best of SDM 2013, Vol:7, No:4, pages:294-307, preprint available as arXiv:1309:3321>
  • K. Subbian, A. Singhal, T. Kolda, A. Pinar, and J. Srivastava, Dynamics of Trust Reciprocation in Multi-Relational Networks, Proc. the IEEE/ACM International Conference on Social Networks Analysis and Mining (ASONAM~2013). preprint available as arXiv:1303.6385
  • M. Jha, C. Seshadhri, and A. Pinar, A Space Efficient Streaming Algorithm for Triangle Counting using the Birthday Paradox, Proc. KDD~13; preprint available as arXiv:1212.2264 .
  • N. Durak, T. Kolda, A. Pinar, and C. Seshadhri, A Scalable Null Model to Match All Degree Distributions: In, Out, and Reciprocal, to appear in Proc. Second IEEE W. Network Science; also available as arXiv:1210.5288
  • K. Subbian, A. Singhal, T. Kolda, A. Pinar, and J. Srivastava, On Reciprocity in Massively Multi-player Online Game Networks, arXiv:1303:6385
  • C. Seshadhri, A. Pinar, and T.Kolda, An In-Depth Analysis of Stochastic Kronecker Graphs, to appear in Journal of the ACM. Available at arxiv. Earlier version appeared in ICDM 11. (pdf)
  • C. Seshadhri, A. Pinar, and T. Kolda, Triadic Measures on Graphs: The Power of Wedge Sampling, arXiv:1202.5230, to appear in Proc. SDM 13.
  • N. Durak, T. Kolda, A. Pinar, and C. Seshadhri, A Scalable directed graph model with reciprocal edges, arXiv:1210.5288.
  • N. Durak, A. Pinar, T. Kolda, and C. Seshadhri, Degree Relations of Triangles in Real-world Networks and Models, arxiv link shorter version to appear in ACM CIKM 12
  • C. Seshadhri, T. Kolda, and A. Pinar, Community structure and scale-free collections of Erdos--Renyi graphs, Physical Review E Vol. 85, No.5
  • J. Ray, A. Pinar, and C. Sehadhri, Are we there yet? When to stop a Markov chain while generating random graphs, WAW 12.
  • A. Pinar, C. Seshadhri, and T.Kolda, The Similarity between Stochastic Kronecker and Chung-Lu Graph Models, SDM'12. preprint available as arXiv:1110.4925
  • M. Rocklin and A. Pinar, On Clustering on Graphs with Multiple Edge Types to appear in Internet Mathamatics (pdf). Thwe work builds on two conference papers published in WAW 11 (pdf) and WAW 10 (pdf).
  • I. Stanton and A. Pinar, Constructing and sampling graphs with prescribed joint degree distribution using Markov Chains, ACM Journal of Experimental Algorithmics . Vol: 17, No. 1, 2012.(pdf) Earlier version appeared in Alenex 11 (pdf)

Complex Networks

High Performance Computing

  • T. Kolda, A. Pinar, T. Plantenga, and C. Seshadhri, A Scalable Generative Graph Model with Community Structure, to appear in SIAM J. Scientific Computing, preprint available as arXiv:1302.6636
  • T. Kolda, A.Pinar, T. Plantenga, C. Seshadhri, and C. Task, Counting Triangles in Massive Graphs with MapReduce, to appear in SIAM J. Scientific Computing; preprint available as arXiv:1301.5887 .
  • D. Thompson, J. Bennett, C. Seshadhri, and A. Pinar, A provably-robust sampling method for generating colormaps of large data, in Proc. IEEE Symposium on Large-Scale Data Analysis and Visualization (LDAV), 2013.
  • E. Kayaaslan, A. Pinar, U. Catalyurek, and C. Aykanat, Partitioning Hypergraphs in Scientific Computing Applications through Vertex Separators on Graphs;, SIAM Scientific Computing, to appear. (pdf)
  • C. Janssen, H. Adalsteinsson, S. Cranford, J. Kenny, A. Pinar, D. Evensky, and J. Mayo, A Simulator for Large-scale Parallel Computer Architectures, International Journal of Distributed Systems and Technology (pdf)
  • S. Kamil, L. Oliker, A. Pinar, and J. Shalf, Communication Requirements and Interconnect Optimization for High-End Scientific Applications, IEEE Transactions on Parallel and Distributed Computing, Vol. 21, No. 2, pages 188--202, 2010. (pdf)
  • A. Pinar, E. Tabak, and C. Aykanat, One dimensional partitioning for hetero- geneous systems, Journal of Parallel and Distributed Computing, Vol. 68, No. 11, pages 1473--1486, 2008. (pdf)

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Ali Pinar
(apinar--sandia--gov)
Phone: (925) 294 4683
Fax: (925) 294 2234