Christopher (Krzysztof) Sikorski, Ph.D.
School of Computing
University of Utah

After a heroic battle with cancer, former CES Program Director and Faculty member Kris Sikorski passed away peacefully July 21st, 2012.

Kris Sikorski in Memoriam

Director, Computational Engineering and Science (CES) Program.

Chair, International Federation for Information Processing Group WG1.1 on Continuous Algorithms and Complexity (IFIP)

Research Interests

Professor Sikorski's research interests are in the areas of parallel scientific computation and computational complexity with special emphasis on information based complexity. Of special interest are applied problems in geophysics like 3-D forward and inverse problems, 3-D migration based on quasi Monte Carlo algorithms, as well as combustion engineering problems (convection-diffusion and fluid mechanics). Professor Sikorski and his students implemented several parallel/distributed algorithms on massively parallel machines and networks of workstations under various programming environments.

Information based complexity is a study of optimal algorithms for problems which are approximately solved, because of partial or contaminated information. Optimal algorithms for solving nonlinear problems are of special interest to Professor Sikorski.


First Prize of the Secretary of National Education (Poland) for the research leading to the publication of the monograph: Selected Topics in Approximation and Computation, joint with M. Kowalski and F. Stenger, Oxford Press, 1996.
Best Paper award, IEEE MFI 2008, joint with T. Henderson, F. Sawo and U. D. Hanebeck, for the paper "Sensor Node Localization Methods based on Local Observations of Distributed Natural Phenomena", Seoul, Korea, August 2008.

Selected Publications

  • Computational Complexity of Fixed Points, K. Sikorski, Journal of Fixed Points Theory and Applications, Birkhauser Basel, Vol 6 No 2, Dec 2009, pp. 249-283 (dedicated to Steve Smale on his 80th birthday).
  • Guest editors' Preface: Issue dedicated to Professor Frank Stenger, B. Bialecki, B. R. Kearfott, K. A. Sikorski, M. Sugihara, Journal of Complexity, Vol 25 Issue 3, June 2009, pp. 233-236.
  • Source Characterization of Atmospheric Releases using Quasi-Random Sampling and Gradient Optimization, Bhagirath Addepalli, Christopher Sikorski, Eric R. Pardyjak, accepted to Inverse problems, 2010.
  • A Note on the Complexity of Fixed Points, S. Shellman, and K. Sikorski, accepted for journal publication, 2010.
  • The Exterior Ellipsoid Algorithm for Fixed Points, Ch. Booniasirivat, K. Sikorski and Ch.W. Tsay, accepted to Mathematics of Computation, 2010 (Dedicated to the memory of L. Khachiyan).
  • Felix Sawo, Thomas C. Henderson, Christopher Sikorski, and Uwe D. Hanebeck, Passive Localization Methods exploiting Models of Distributed Natural Phenomena, Lecture Notes in Electrical Engineering, Springer Verlag, Vol 35, 2009, pp. 375-392.
  • A Note on two fixed point problems, Ch. Booniasirivat, K. Sikorski and Ch. Xiong, Journal of Complexity, 23, 2007, pp. 952-961.;
  • Algorithm 848: A Recursive Fixed Point Algorithm for the Infinity-Norm Case, with S. Shellman, ACM ToMS 31, 4, Dec, 2005, pp. 580-587.
  • Algorithm 825: A Deep-Cut Bisection Envelope Algorithm for Fixed Points, with S. Shellman, ACM ToMS, Vol 29, No. 3, 2003, 309-325.
  • Massively Parallel Linear-scaling Algorithm in the {\em ab-initio} tight-bounding Fireball Method, with S. Shellman, J. Lewis and G. Voth, {\em Journal of Computational Physics}, 188, 2003, 1-15.
  • A Recursive Algorithm for the Infinity Norm Fixed Point Problem, with S. Shellman, J. Complexity, 19, 2003, pp. 799-834.
  • A Two Dimensional Bisection-Envelope Algorithm for Fixed Points, with S. Shellman, J. Complexity 18, June, 2002, pp. 641-659.
  • Computing Fixed Points of Mildly Contractive Functions, with Leonid Khachiyan and Zhijian Huang, J. Complexity 15, pp. 200-213, June, 1999.
  • A Quasi- Monte Carlo Approach to Efficient 3D Migration, with G. Schuster, and Y. Sun, Geophysics, Vol. 62, No. 3, 1997, pp. 918-929.
  • A Note on a Linear Time Algorithm for Constructing Adjacency Graphs in FEM Data, with S.K. Ueng, The Visual Computer, Vol. 12, No. 9, Dec. 1996, pp. 445-450.
  • Efficient Construction of Streamlines, Streamribbons and Streamtubes on Unstructured Grids, with S.K. Ueng and K.L. Ma, IEEE Transactions on Visualization and Graphics, Vol. 2, No. 2, June, 1996, pp. 100-109.
  • Distributed Combustion Simulations, with. P.Smith, B. Adams and K-L. Ma, Energy and Fuels, Dec. 1993
  • An Ellipsoid Algorithm for the Computation of Fixed Points, with Ch-W. Tsay, and H.Wozniakowski, Journal of Complexity No. 9, March, 1993, pp. 181-200.
  • Complexity of Fixed Points, with H.Wozniakowski, Journal of Complexity, No. 3, Dec. 1987, pp. 388-405.