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[ Network/graph analysis | Sparse matrix computations | Parallel computing | CS education | Other ]

At the moment I'm mostly thinking about network analysis. Other research interests include sparse matrix computations, high performance computing (particularly performance modelling), algorithms, and computer science education.

Below (in no particular order) is more information on various aspects of my work. Some publications are listed in more than one category. A [*] indicates that a co-author was an undergraduate at the time they did the work. A [**] indicates that a co-author was a post-baccalaureate researcher.

Network/graph analysis

  • Some topics of interest:
  • algorithms
  • evaluating the meaningfulness of answers
  • applications "in the real world"
  • Publications:
  • S. Bhowmick, T.-Y. Chen, and M. Halappanavar. A new augmentation based algorithm for extracting maximal chordal subgraphs. Journal of Parallel and Distributed Computing, 2015. <ScienceDirect link>
  • K. Dempsey, T.-Y. Chen, S. Srinivasan, S. Bhowmick, and H. Ali. A structure-preserving hybrid-chordal filter for sampling in correlation networks. Proceedings of the 2013 International Conference on High Performance Computing & Simulation (HPCS), 2013. <IEEE Xplore link>
  • T.-Y. Chen and E. Fields*. Evaluating the stability of communities found by clustering algorithms. Proceedings of the 4th International Workshop on Complex Networks, 2013. <SpringerLink>
  • K. Dempsey, T.-Y. Chen, S. Bhowmick, and H. Ali. On the design of advanced filters for biological networks using graph theoretic properties. Proceedings of the 2012 IEEE International Conference on BioInformation and BioMedicine, 2012. <IEEE Xplore link>
  • Sparse Matrix Computations

  • Some topics of interest:
  • preconditioners
  • perfect-elimination orderings
  • fill-reducing orderings
  • incomplete LU preconditioners
  • balancing sparse matrices
  • Publications:
  • L. Peairs** and T.-Y. Chen. Using reinforcement learning to vary the m in GMRES(m). Proceedings of the 2011 International Conference on Computational Science, also Procedia Computer Science, 4: 22572266. 2011. < ScienceDirect link>
  • E. Kuefler* and T.-Y. Chen. On using reinforcement learning to solve sparse linear systems. Proceedings of the International Conference on Computational Science, also Lecture Notes in Computer Science, 5101: 955-964, 2008. <DOI link>
  • A. Holloway** and T.-Y. Chen. Neural networks for predicting the behavior of preconditioned iterative solvers. Proceedings of the International Conference on Computational Science, also Lecture Notes in Computer Science, 4487: 302--309, 2007. <DOI link> <pdf>
  • M. Lazzareschi* and T.-Y. Chen. Using performance profiles to evaluate preconditioners for iterative methods. Proceedings of the 2006 International Conference on Computational Science and its Applications, also Lecture Notes in Computer Science, 3982: 1081--1089, 2006. <DOI link>
  • T.-Y. Chen and M. Egan**. On the existence of nonsymmetric matrices with perfect elimination orderings. Proceedings of the Fifth Grace Hopper Celebration of Women in Computing, 2004. <pdf> <ps>
  • T.-Y. Chen. ILUTP_Mem: A space-efficient incomplete LU preconditioner, Proceedings of the 2004 International Conference on Computational Science and its Applications, also Lecture Notes in Computer Science, 3046: 31--39, 2004. <springerlink>
  • T.-Y. Chen and J. Demmel. Balancing sparse matrices for computing eigenvalues. Linear Algebra and Its Applications, 309: 261--287, 2000. <pdf> <ps>
  • T.-Y. Chen and J. Demmel. Balancing sparse matrices for computing eigenvalues. Section 7.2 in Templates for the Solution of Algebraic Eigenvalue Problems: A Practical Guide. Editors Z. Bai, J. Demmel, J. Dongarra, A. Ruhe, and H. van der Vorst. SIAM, Philadelphia, 2000. <online book>
  • T.-Y. Chen, J. Gilbert, and S. Toledo. Toward an efficient column minimum degree code for symmetric multiprocessors. Proceedings of the 9th SIAM Conference on Parallel Processing for Scientific Computing, 1999. <pdf> <ps>
  • Posters:
  • L. Peairs** and T.-Y. Chen. On the effect of varying the restart parameter of GMRES(m). In Grace Hopper Celebration of Women in Computing. Atlanta, GA. September 2010.
  • S. Ehrlich* and T.-Y. Chen. Minimum fill with column permutations is NP-complete. In SIAM Workshop on Combinatorial Scientific Computing. Monterey, CA. October 2009.
  • A. Holloway** and T.-Y. Chen. Using supervised machine learning techniques to understand preconditioner behavior. In SIAM Conference on Computational Science and Engineering. Costa Mesa, CA. February 2007.
  • Theses:
  • T.-Y. Chen. Preconditioning sparse matrices for computing eigenvalues and solving linear systems of equations. Ph.D. Thesis, Computer Science Division, UC Berkeley, 2001. <pdf> <abstract>
  • T.-Y. Chen. Balancing sparse matrices for computing eigenvalues. Masters Thesis, Computer Science Division, UC Berkeley, 1998. <ps> <pdf>
  • High Performance Computing

  • Some topics of interest:
  • performance modeling
  • workload characterization
  • algorithms
  • Publications:
  • S. Bhowmick, T.-Y. Chen, and M. Halappanavar. A new augmentation based algorithm for extracting maximal chordal subgraphs. Journal of Parallel and Distributed Computing, 2015. <ScienceDirect link>
  • T.-Y. Chen, O. Khalili, R. L. Campbell Jr., L. Carrington, M. Tikir, and A. Snavely. Performance prediction and ranking of supercomputers. Chapter 3 in High Performance Computing, volume 72 in series Advances in Computers. Academic Press, 2008.
  • T.-Y. Chen, M. Gunn*, B. Simon, L. Carrington, and A. Snavely. Metrics for ranking the performance of supercomputers. Cyberinfrastructure Technology Watch, 2(4B): 59--67, November 2006. <html>
  • T.-Y. Chen, J. Gilbert, and S. Toledo. Toward an efficient column minimum degree code for symmetric multiprocessors. Proceedings of the 9th SIAM Conference on Parallel Processing for Scientific Computing, 1999. <pdf> <ps> <overview>
  • T.-Y. Chen. The effect of caches on the performance analysis of data parallel CM-Fortran programs. Proceedings of the 1994 MIT Student Workshop on Scalable Computing, MIT LCS TR-622, 1994.
  • CS Education Research

  • Some topics of interest:
  • Diversity, outreach
  • Pre-conceptions, pre-existing knowledge (Commonsense Computing group)
  • Student approaches to design ( Multi-national, multi-institutional study of student-generated software designs )
  • Publications:
  • D. Bouvier, T.-Y. Chen, G. Lewandowski, R. McCartney, K. Sanders, and T. VanDeGrift. User evaluation by novices. Proceedings of the 17th Annual Conference on Innovation and Technology in Computer Science Education (ITiCSE), 2012. <ACM DL link>
  • M. Gonzalez, L. Vasserman, S. Sood, and T.-Y. Chen. Leveraging existing outreach programs to reach underrepresented minorities, in Proceedings of the Fourth Annual Conference of the Southwestern Region of the Consortium for Computing Sciences in Colleges, 2011. <pdf>
  • T. VanDeGrift, D. Bouvier, T.-Y. Chen, G. Lewandowski, R. McCartney, K. Sanders, and B. Simon. Commonsense computing (episode 7): Logic is harder than pie, Proceedings of 10th Koli Calling International Conference on Computing Education Research. October 2010.
  • G. Lewandowski, D. Bouvier, T.-Y. Chen, R. McCartney, K. Sanders, B. Simon, and T. VanDeGrift. Commonsense understanding of concurrency: Computing students and concert tickets, Communications of the ACM, 53(7): 60-70. July 2010. < DOI link>
  • R. McCartney, D. Bouvier, T.-Y. Chen, G. Lewandowski, K. Sanders, B. Simon, and T. VanDeGrift. Commonsense probability: Preconceptions of entering engineering students, In Proceedings of Frontiers in Education (FIE), 2009. San Antonio, TX <pdf>
  • R. McCartney, D. Bouvier, T.-Y. Chen, G. Lewandowski, K. Sanders, B. Simon, and T. VanDeGrift. Commonsense computing (episode 5): Algorithm efficiency and balloon testing, In Proceedings of the 2009 International Computer Science Education Research Workshop (ICER), 2009. Berkeley CA. < DOI link>
  • B. Simon, D. Bouvier, T.-Y. Chen, G. Lewandowski, R. McCartney, and K. Sanders. Commonsense computing (episode 4): Debugging. Computer Science Education, special issue on debugging, 18(2): 117-133, 2008.
  • T.-Y. Chen, G. Lewandowski, R. McCartney, K. Sanders, and B. Simon. Commonsense Computing: using student sorting abilities to improve instruction. In Proceedings of SIGCSE, 2007. <DOI link>
  • B. Simon, T.-Y. Chen, G. Lewandowski, R. McCartney, and K. Sanders. Commonsense computing: What students know before we teach (Episode 1: Sorting). In the Proceedings of the 2006 International Computer Science Education Research Workshop (ICER), 2006. Canterbury, UK. <DOI link>
  • T.-Y. Chen, A. Monge, and B. Simon. Relationship of early programming language to novice generated design. In Proceedings of the 2006 Technical Symposium on Computer Science Education (SIGCSE), 2006. <DOI link>
  • T.-Y. Chen, S. Cooper, R. McCartney, and L. Schwartzman. The (relative) importance of software design criteria. In Proceedings of the 10th Annual Conference on Innovation and Technology in Computer Science Education (ITiCSE), 2005. Also SIGCSE Bulletin, 37(3): 34--38, September 2005. <DOI link>
  • S. Fincher, M. Petre, J. Tenenberg, K. Blaha, D. Bouvier, T.-Y. Chen, D. Chinn, S. Cooper, A. Eckerdal, H. Johnson, R. McCartney, A. Monge, J. E. Mostrom, K. Powers, M. Ratcliffe, A. Robins, D. Sanders, L. Schwartzman, B. Simon, C. Stoker, A. E. Tew, T. VanDeGrift. Cause for alarm?: A multi-national, multi-institutional study of student-generated software designs. In the Proceedings of the 4th Annual Finnish/Baltic Sea Conference on Computer Science Education, 2004. Invited to Informatics in Education, 4(1): 143--162, 2005. (Earlier version available as tech report: University of Kent, Canterbury: Computing Laboratory, Technical Report No. 16-04, 2004. <abstract> <pdf>)
  • Posters:
  • T.-Y. Chen, G. Lewandowski, R. McCartney, K. Sanders, and B. Simon. What do beginning students know, and what can they do? In Proceedings of the 11th Annual Conference on Innovation and Technology in Computer Science Education (ITiCSE), 2006. Also SIGCSE Bulletin, 38(3): 329, September 2006. <DOI link>
  • Other

  • Publications:
  • P. McCormack* and T.-Y. Chen. Optimizing leader proportion and behavior for evacuating buildings. Proceedings of the Symposium on Agent-Directed Simulation, 2014.
  • S. Azenkot*, T.-Y. Chen, and G. Cormode. An evaluation of the edit-distance-with-moves metric for comparing genetic sequences. DIMACS Technical Report 2005-39, November 2005. <abstract> <ps.gz>
  • [*] work done while an undergraduate researcher
    [**] work done while a postbaccalaureate researcher


    The research on sparse matrices was funded in part by an NSF CAREER grant (abstract).
    The research in computer science education was funded in part by an NSF CCLI grant. (abstract).
    "If we knew what it was we were doing, it would not be called research, would it?"
    -- Albert Einstein