Sandia National Laboratories
Ali Pinar

Ali Pinar's Homepage

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, and like. I have been alfo looking at power systems with fovus 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, yo ucan look at my CV ...

Recent Activities

Recent Publications

Modeling and Analysis of Graphs

  • C. Seshadhri, A. Pinar, N. Durak, and T. Kolda, Directed closure measures for networks with reciprocity, submitted for journal publication, also available on arxiv as: arXiv:1302:6220
  • C. Seshadhri, A. Pinar, and T. Kolda, Wedge Sampling for Computing Clustering Coefficients and Triangle Counts on Large Graphs, submitted to Statistical Analysis and Data Mining special issue for Best of SDM 2013.
  • 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).
  • M. Jha, C. Seshadhri, and A. Pinar, A Space Efficient Streaming Algorithm for Triangle Counting using the Birthday Paradox, Proc. KDD~13; also available on arxiv as arXiv:1212.2264 .
  • T. Kolda, A.Pinar, T. Plantenga, C. Seshadhri, and C. Task, Counting Triangles in Massive Graphs with MapReduce, submitted to SIAM J. Scientific Computing; also available as arXiv:1301.5887 .
  • T. Kolda, A. Pinar, T. Plantenga, and C. Seshadhri, " A Scalable Generative Graph Model with Community Structure," submitted to SISC, also available as arXiv:1302.6636 .
  • 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.
  • C. Seshadhri, A. Pinar, N. Durak, and T. Kolda, " The importance of directed triangles with reciprocity: patterns and algorithms," submitted for conference publication, also available on arxiv as:
  • K. Subbian, A. Singhal, T. Kolda, A. Pinar, and J. Srivastava, " On Reciprocity in Massively Multi-player Online Game Networks," arXiv:1303:6385
  • T. Kolda, T. Plantenga, C. Task, A.Pinar, and C. Seshadhri, " Counting Triangles in Massive Graphs with MapReduce, " submitted to SISC; also available as arXiv:1301.5887.
  • 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.
  • J. Ray, A. Pinar, and C. Seshadhri, " A stopping criterion for Markov chainswhen generating independent random graphs," arXiv:1210.8184 Earlier version appeared in WAW 12 (pdf).
  • 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,
  • A. Pinar, C. Seshadhri, and T.Kolda," The Similarity between Stochastic Kronecker and Chung-Lu Graph Models, to appear in SDM'12 " arxiv link
  • 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

  • R. Chen, A. Cohn, N. Fan, and A. Pinar, "Contingency-Risk Informed Power System Design," submitted; also available as arXiv:1305.0780.
  • R. Chen, N. Fan, A. Pinar, and J. Watson, " Contingency-Constrained Unit Commitment with Post-Contingency Corrective Recourse," submitted to INFORMS J. Computing.
  • C. Quinn, A. Pinar, and N. Kiyavash, " Optimal Bounded-Degree Approximations of Joint Distributions of Networks of Stochastic Processes," in Proc.of ISIT 13.
  • R. Chen, A. Cohn, N. Fan, and A. Pinar, N-k-epsilon Survivable Power System Design,in Proc.PMAPS 12, (pdf) .
  • R. Chen, A. Cohn, and A. Pinar, " An Implicit Optimization Approach for Survivable Network Design," in Proc. First IEEE Network Science Workshop. (pdf)
  • A. Pinar, J. Meza, V. Donde, and B. Lesieutre, Optimization Strategies for the Vulnerability Analysis of the Power Grid, SIAM Journal on Optimization, Vol. 20, No. 4, pages 1786--1810, 2010. (pdf)
  • V. Donde, V. Lopez, B. Lesieutre, A. Pinar, C. Yang, and J. Meza, Severe Multiple Contingency Screening in Electric Power Systems, IEEE Transactions on Power Systems, Vol. 23, No. 2, pages 406--417, 2008. (pdf)
  • B. Lesieutre, A. Pinar, and S. Roy, Power System Extreme Event Detection: The Vulnerability Frontier, in Proc. 41st Hawaii International Conference on System Sciences, pages: 184, Waikoloa, Big Island, HI, 2008. (pdf)

High Performance Computing

  • 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
Phone: (925) 294 4683
Fax: (925) 294 2234