Margareta Ackerman
Ph.D.


 Department of Computing + Mathematical Sciences
California Institute of Technology
mackerma.at.caltech.edu

I am a Postdoctoral Fellow at Caltech. I got my PhD in Computer Science from the University of Waterloo under the supervision of Professor Shai Ben-David. My primary research interest is developing theoretical foundations of clustering that are independent of any specific algorithm or objective function. We provide a consistent set of axioms for clustering and perform a theoretical study of clusterability (NIPS '08 and AISTATS '09). My recent work focuses on providing guidelines for selecting clustering algorithms based on their input-output behaviour (AISTATS '13, AAAI '12, IJCAI '11, NIPS '10, COLT '10).

Received the Outstanding Achievement in Graduate Studies Award for my Master's degree, with the thesis A Theoretical Study of Clusterability and Clustering Quality.

Co-organized a clustering workshop at NIPS '09 with Shai Ben-David, Ulrike von Luxburg, Avrim Blum, Isabelle Guyon, Robert C. Williamson, and Reza Bosagh Zadeh.


Publications

Conference and Journal Publications

  • Margareta Ackerman and Shai Ben-David. A Characterization of Linkage-Based Hierarchical Clustering. Journal of Machine Learning Research (JMLR), 2013.

  • Margareta Ackerman, Shai Ben-David, Sivan Sabato, and David Loker. Clustering Oligarchies. Proceedings of the Twelfth International Conference on Artificial Intelligence and Statistics (AISTATS), 2013.

  • Margareta Ackerman, Shai Ben-David, Simina Branzei, and David Loker. Weighted Clustering. Proc. 26th AAAI Conference on Artificial Intelligence, 2012.

  • Margareta Ackerman, Dan Brown, and David Loker. Effects of Rooting via Outgroups on Ingroup Topology in Phylogeny. IEEE International Conference on Computational Advances in Bio and Medical Sciences (ICCABS 2012). [slides] Journal version in BMC Genomics upcoming.

  • Joshua Lewis, Margareta Ackerman, and Virginia De Sa. Human Cluster Evaluation and Formal Quality Measures. Proc. 34th Annual Conference of the Cognitive Science Society, 2012.

  • Margareta Ackerman and Shai Ben-David. Discerning Linkage-Based Algorithms Among Hierarchical Clustering Methods. International Joint Conference on Artificial Intelligence (IJCAI 2011). (Presentation acceptance rate: 17%). [slides]

  • Margareta Ackerman, Shai Ben-David, and David Loker. Towards Property-Based Classification of Clustering Paradigms. Neural Information Processing Systems Conference (NIPS 2010). [Appendix]

  • Margareta Ackerman, Shai Ben-David, and David Loker. Characterization of Linkage-Based Clustering. 23rd International Conference on Learning Theory (COLT 2010). [slides]

  • Margareta Ackerman and Shai Ben-David. Clusterability: A Theoretical Study. Proceedings of the Twelfth International Conference on Artificial Intelligence and Statistics (AISTATS 2009), JMLR: W&CP 5, pp. 1-8. (Presentation acceptance rate: 10%). [slides]

  • Margareta Ackerman and Erkki Makinen. Three New Algorithms for Regular Language Enumeration, Computing and Combinatorics: 15th Annual International Conference (COCOON) , Lecture Notes in Computer Science 5609, Springer-Verlag, Berlin Heidelberg, pp. 178-191, 2009. [slides]

  • Margareta Ackerman and Jeffrey Shallit. Efficient Enumeration of Words in Regular Languages. Theoretical Computer Science (2009) V. 410 (37), Elsevier, pp. 3461-3470.

  • Margareta Ackerman and Shai Ben-David. Measures of Clustering Quality: A Working Set of Axioms for Clustering. Neural Information Processing Systems Conference (NIPS 2008)
    (full oral presentation, acceptance rate: 2.7%) [slides]

  • Margareta Ackerman and Jeffrey Shallit. Efficient Enumeration of Regular Languages. Conference on Implementation and Application of Automata (CIAA) , Lecture Notes in Computer Science, 4783, Springer-Verlag, Berlin Heidelberg, pp. 226-241, 2007. [slides]

  • Daniel Maoz and Margareta Ackerman, "Chavruta and Transformative Learning: A Comparative Analysis," in Opportunities and New Directions: Canadian Scholarship of Teaching and Learning (Edited by N. Simmons. Waterloo: CTE, 2010) pp. 51-59.

  • Daniel Maoz and Margareta Ackerman. "Chavruta: A Novel Teaching Methodology Based on an Ancient Tradition." From Antiquity to the Post-Modern World: Contemporary Jewish Studies in Canada. Newcastle upon Tyne: Cambridge Scholars Publishing, 193-205, 2011.

Workshops

  • Margareta Ackerman. Towards Theoretical Foundations of Clustering. Grace Hopper Celebration (GHC), 2011.

  • Margareta Ackerman, Shai Ben-David, and David Loker. Characterization of Linkage-Based Clustering. NIPS workshop ``Clustering: Science or Art? Towards Principled Approaches.'', 2009.

Invited Talks


Conference Talks


Journal/Conference Referee

  • Journal of Machine Learning Research.

  • IEEE Transactions on Pattern Analysis and Machine Intelligence (TPAMI).

  • The Journal of Pattern Recognition.

  • Transactions on Knowledge and Data Engineering.

  • Neural Information Processing Systems (NIPS) 2010, 2012.

  • International Conference on Machine Learning (ICML), 2012-2013.