Eftychios Sifakis

Associate Professor

Computer Science Department, University of Wisconsin-Madison

Contact Information:

University of Wisconsin Madison

Computer Sciences Bldg, Room 6387

1210 W Dayton St.

Madison WI 53706

Email : *sifakis *AT *cs *DOT *wisc *DOT *edu*

Professional information

I am an associate professor of Computer Science at the University of Wisconsin-Madison. I joined the department in January of 2011.

Between 2007-2010 I was a post-doctoral researcher at the University of California Los Angeles, jointly appointed to the departments of Mathematics and Computer Science. I completed my PhD degree in Computer Science at Stanford University, under the supervision of Ron Fedkiw. Before moving to the United States, I completed a B.Sc in Computer Science (2000) and a B.Sc in Mathematics (2002), both from the University of Crete, Greece.

My current research revolves around the areas of computer graphics, physics-based modeling/simulation and scientific computing. I am particularly interested in the development of algorithms and numerical techniques that can facilitate the efficient and accurate simulation of parts of the human body, with focus on applications in biomechanics and virtual surgery.

Biographical sketch

Curriculum Vitae

Project descriptions (with illustrations and videos)

Teaching

At UW-Madison:

CS839 -
Topics in Computing : Physics-Based Modeling and Simulation (Spring 2022)

CS559 - Computer Graphics (Fall 2021)

CS639 -
Undergraduate Topics in Computing : Parallel and Throughput-Optimized
Programming (Spring 2021)

CS559 - Computer Graphics (Fall 2020)

CS639 -
Undergraduate Topics in Computing : Parallel and Throughput-Optimized
Programming (Spring 2020)

CS839 -
Topics in Computing : Physics-Based Modeling and Simulation (Fall 2019)

CS559 - Computer Graphics (Fall 2016)

CS559 - Computer Graphics (Spring 2016)

CS559 - Computer Graphics (Fall 2015; jointly with Michael Gleicher)

CS838 - Topics in Computing : Advanced Computer Graphics (Fall 2015)

CS559 - Computer Graphics (Spring 2014)

CS838 - Topics in Computing : Advanced Computer Graphics (Fall 2014)

CS838 - Topics in Computing : Introduction to Physics-Based Modeling and Simulation (Spring 2014)

CS412 - Introduction to Numerical Methods (Spring 2013)

CS838 - Topics in Computing : Introduction to Physics-Based Modeling and Simulation (Fall 2012)

CS412 - Introduction to Numerical Methods (Spring 2012)

CS838 - Topics in Computing : Advanced Modeling and Simulation (Fall 2011)

CS412 - Introduction to Numerical Methods (Spring 2011)

At UCLA:

Math 151B - Applied Numerical Methods (Winter 2009-2010)

**Publications**

- H. Liu*, Y. Hu*, B. Zhu, W. Matusik,
**E. Sifakis**(*Joint first authors), "Narrow-Band Topology Optimization On A Sparsely Populated Grid", ACM Transactions on Graphics 37:4 (Proceedings of ACM SIGGRAPH Asia), 2018 [PDF]. - M. Gao*, X. Wang*, K. Wu*, A. Pradhana,
**E. Sifakis**, C. Yuksel, and C. Jiang (*Joint first authors), "GPU Optimization of Material Point Methods", ACM Transactions on Graphics 37:6 (Proceedings of ACM SIGGRAPH Asia), 2018 [PDF]. - S. Lee, R. Yu, J. Park, M. Aanjaneya,
**E. Sifakis**, J. Lee, "Dexterous Manipulation and Control with Volumetric Muscles", ACM Transactions on Graphics 37:4 (Proceedings of ACM SIGGRAPH), 2018 [PDF]. - M. Gao, A. Pradhana, X. Han, Q. Guo, G. Kot,
**E. Sifakis**, C. Jiang, "Animating Fluid Sediment Mixture in Particle-Laden Flows", ACM Transactions on Graphics 37:4 (Proceedings of ACM SIGGRAPH), 2018 [PDF]. - M. Gao, A. Pradhana, C. Jiang,
**E. Sifakis**, "An Adaptive Generalized Interpolation Material Point Method for Simulating Elastostatic Materials", ACM Transactions on Graphics 36:6 (Proceedings of SIGGRAPH Asia), 2017 [PDF]. - S. Lee, N. Mitchell, M. Aanjaneya,
**E. Sifakis**, J. Lee, "Volumetric Muscle Controller", Symposium on Computer Animation (Posters), 2017 [ACM/DL Link] - M. Aanjaneya*, M. Gao*, H. Liu, C. Batty,
**E. Sifakis**(*Joint first authors), "Power Diagrams and Sparse Paged Grids for High Resolution Adaptive Liquids", ACM Transactions on Graphics 36:4 (Proceedings of ACM SIGGRAPH), 2017 [PDF] - H. Liu, N. Mitchell, M. Aanjaneya,
**E. Sifakis**, "A scalable Schur-complement fluids solver for heterogeneous compute platforms", ACM Transactions on Graphics 35:6 (Proceedings of ACM SIGGRAPH Asia), 2016 [PDF] - N. Mitchell, M. Doescher,
**E. Sifakis**, "A macroblock optimization for grid-based nonlinear elasticity", Eurographics/ACM SIGGRAPH Symposium on Computer Animation, 2016 [PDF] - N. Mitchell, C. Cutting, T. King, A. Oliker,
**E. Sifakis**, "A Real-Time Local Flaps Surgical Simulator Based on Advances in Computational Algorithms for Finite Element Models", Journal of Plastic and Reconstructive Surgery, 137(2), 2016 [PDF] - C. L. Anumolu, M. Aanjaneya,
**E. Sifakis**, M. Trujillo, "Simulating Phase-Change Phenomena Using Gradient Augmented Level Set Approach", ILASS Americas 28th Annual Conference on Liquid Atomization and Spray Systems, 2016 [PDF] - T. Liu, M. Gao, L. Zhu,
**E. Sifakis**, L. Kavan, "Fast and Robust Inversion-Free Shape Manipulation", Proceedings of EUROGRAPHICS, 2016 [PDF] **E. Sifakis**, J. Barbic, "Finite Element Method Simulation of 3D Deformable Solids", Synthesis Lectures on Visual Computing, Morgan & Claypool publishers, 2015 [Amazon Link] [SIGGRAPH Course notes]- N. Mitchell, M. Aanjaneya, R. Setaluri,
**E. Sifakis**, "Non-manifold level sets: a multivalued implicit surface representation with applications to self-collision processing", ACM Transactions on Graphics 34:6 (Proceedings of ACM SIGGRAPH Asia), 2015 [PDF] - N. Mitchell, C. Cutting,
**E. Sifakis**, "GRIDiron: An interactive authoring and cognitive training foundation for reconstructive plastic surgery procedures", ACM Transactions on Graphics (Proceedings of ACM SIGGRAPH), 2015 [PDF] - W. Si, S.-H. Lee,
**E. Sifakis**, D. Terzopoulos, "Realistic Biomechanical Simulation and Control of Human Swimming", ACM Transactions on Graphics (also presented at SIGGRAPH 2015), 2014 [PDF] - R. Setaluri, M. Aanjaneya, S. Bauer,
**E. Sifakis**, "SPGrid: A Sparse Paged Grid Structure Applied to Adaptive Smoke Simulation", ACM Transactions on Graphics (Proceedings of SIGGRAPH Asia), 2014 [PDF] - M. Gao, N. Mitchell,
**E. Sifakis**, "Steklov-Poincaré Skinning", Eurographics/ACM SIGGRAPH Symposium on Computer Animation, 2014 [PDF] - R. Setaluri, Y. Wang, N. Mitchell, L. Kavan,
**E. Sifakis**, "Fast Grid-Based Nonlinear Elasticity for 2D Deformations", Eurographics/ACM SIGGRAPH Symposium on Computer Animation, 2014 [PDF] - T. Heyn, H. Mazhar, A. Pazouki, D. Melanz, A. Seidl, A. Bartholomew, L. Fang, A. Tasora,
**E. Sifakis**, D. Negrut, "Chrono: A Parallel Multi-Physics Library for Rigid-Body, Flexible-Body, and Fluid Dynamics", ECCOMAS Thematic Conference on Multibody Dynamics, Zagreb, Croatia, 2013 [PDF] - T. Patterson, N. Mitchell and
**E. Sifakis**, "Simulation of Complex Nonlinear Elastic Bodies using Lattice Deformers", ACM Transactions on Graphics (SIGGRAPH Asia proceedings), 31(6), pp.197:1-11, 2012. [PDF] - Y. Zhu, Y. Wang, J. Hellrung, A. Cantarero,
**E. Sifakis**, J. Teran, "A Second-Order Virtual Node Algorithm for Nearly Incompressible Linear Elasticity in Irregular Domains", Journal of Computational Physics, 231(21), pp. 7092-7117, 2012. [PDF] - J. Hellrung, L. Wang,
**E. Sifakis**and J. Teran, "A Second-Order Virtual Node Method for Elliptic Problems with Interfaces and Irregular Domains in Three Dimensions", Journal of Computational Physics, 231(4), pp. 2015-2048, 2012 [PDF] - A. McAdams, Y. Zhu, A. Selle, M. Empey, R. Tamstorf, J. Teran and
**E. Sifakis**, “Efficient elasticity for character skinning with contact and collisions”, ACM Transactions on Graphics (SIGGRAPH 2011), 30(4), pp.37:1-37:12, 2011 [PDF] - C. L. Richardson, J. Hegeman,
**E. Sifakis**, J. Hellrung and J. Teran, “An XFEM method for modelling geometrically elaborate crack propagation in brittle materials”, International Journal for Numerical Methods in Engineering, 88(10), pp. 1042-1065, 2011 [PDF] - A. McAdams,
**E. Sifakis**and J. Teran, “A parallel multigrid Poisson solver for fluids simulation on large grids”, ACM SIGGRAPH/Eurographics Symposium on Computer Animation (SCA), edited by M. Otaduy and Z. Popovic, 2010 [PDF] [Source Code] - J. Bedrossian, J. H. von Brecht, S. Zhu,
**E. Sifakis**and J. Teran, “A Second Order Virtual Node Method for Elliptic Problems with Interfaces and Irregular Domains”, Journal of Computational Physics, 229, pp. 6405-6426, 2010 [PDF] - Y. Zhu,
**E. Sifakis**, J. Teran and A. Brandt, “An efficient multigrid method for the simulation of high-resolution elastic solids”, ACM Transactions on Graphics 29(2), pp.16:1-16:18, 2010 (presented at SIGGRAPH 2010) [PDF] - S.-H. Lee,
**E. Sifakis**and D. Terzopoulos, “Comprehensive Biomechanical Modeling and Simulation of the Upper Body”, ACM Transactions on Graphics 28(4), pp.99:1-99:17 2009 (presented at SIGGRAPH 2010) [PDF] - A. McAdams, A. Selle, K. Ward,
**E. Sifakis**and J. Teran, “Detail preserving continuum simulation of straight hair”, ACM Transactions on Graphics (SIGGRAPH Proceedings), 28(3), 2009 [PDF] - J. Hellrung, A. Selle, A. Shek,
**E. Sifakis**and J. Teran, “Geometric fracture modeling in BOLT, ACM SIGGRAPH Talks (Sketch), 2009 [PDF] **E. Sifakis**, J. Hellrung, J. Teran, A. Oliker and C. Cutting, “ Local Flaps: A Real-Time Finite Element Based Solution to the Plastic Surgery Defect Puzzle”, Medicine Meets Virtual Reality 17, 2009 [PDF]**E. Sifakis**, S. Marino and J. Teran, “Globally Coupled Impulse-Based Collision Handling for Cloth Simulation”, ACM SIGGRAPH/Eurographics Symposium on Computer Animation (SCA), edited by M. Gross and D. James, 2008 [PDF]**E. Sifakis**, T. Shinar, G. Irving and R. Fedkiw, “Hybrid Simulation of Deformable Solids”, ACM SIGGRAPH/Eurographics Symposium on Computer Animation (SCA), edited by D. Metaxas and J. Popovic, 2007 [PDF]**E. Sifakis**, K. Der, and R. Fedkiw, “Arbitrary Cutting of Deformable Tetrahedralized Objects”, ACM SIGGRAPH/Eurographics Symposium on Computer Animation (SCA), edited by D. Metaxas and J. Popovic, 2007 [PDF]- C. Hughes, R. Grzeszczuk,
**E. Sifakis**, D. Kim, S. Kumar, A. Selle, J. Chhugani, M. Holliman, Y.-K. Chen, “Physical Simulation for Animation and Visual Effects: Parallelization and Characterization for Chip Multiprocessors”, IEEE/ACM International Symposium on Computer Architecture (ISCA), 2007 [PDF] **E. Sifakis**, “Algorithmic Aspects of the Simulation and Control of Computer Generated Human Anatomy Models”, Ph.D. Thesis, Stanford University, 2007 [PDF]**E. Sifakis**, A. Selle, A. Robinson-Mosher and R. Fedkiw, “Simulating Speech with a Physics-Based Facial Muscle Model”, ACM SIGGRAPH/Eurographics Symposium on Computer Animation (SCA), edited by M.-P. Cani and J. O’Brien, 2006 [PDF]**E. Sifakis**, I. Neverov and R. Fedkiw, “Automatic Determination of Facial Muscle Activations from Sparse Motion Capture Marker Data”, ACM Transactions on Graphics (SIGGRAPH Proceedings), TOG 24, pp. 417-425, 2005 [PDF]- J. Teran,
**E. Sifakis**, G. Irving and R. Fedkiw, “Robust Quasistatic Finite Elements and Flesh Simulation”, ACM/Eurographics Symposium on Computer Animation (SCA), edited by K. Anjyo and P. Faloutsos, pp. 181-190, 2005 [PDF] - J. Teran,
**E. Sifakis**, S. Blemker, V. Ng Thow Hing, C. Lau and R. Fedkiw, “Creating and simulating skeletal muscle from the Visible Human Data Set”, IEEE Transactions on Visualization and Computer Graphics, 11, pp. 317-328, 2005. [PDF] **E. Sifakis**and R. Fedkiw, “Facial Muscle Activations from Motion Capture”, in video proceedings of the Computer Vision and Pattern Recognition Conference (CVPR), 2005 [PDF]- S. Blemker, J. Teran,
**E. Sifakis**, R. Fedkiw and S. Delp, “Fast 3D Muscle Simulations Using a New Quasistatic Invertible Finite-Element Algorithm”, International Symposium on Computer Simulation in Biomechanics, 2005 [PDF] - P. Sundaram,
**E. Sifakis**, D. S. Paik, C. F. Beaulieu, S. Napel, “Fold Removal in CT Colonography (CTC): A Physics-based Approach”, Radiological Society of North America 91st Scientific Sessions, November, 2005. Scientific Assembly and Annual Meeting Program 2005:439 - P. Sundaram, D.S. Paik,
**E.D. Sifakis**, C.F. Beaulieu and S. Napel, “Selective Fold Removal in CT colonography using physically-based simulation,” Fifth International Symposium on Virtual Colonoscopy, Boston, MA October 28-29, 2004 - P. Sundaram,
**E. Sifakis**, D.S. Paik, C.F. Beaulieu, S. Napel, “Physically based approach to removal of folds in CT Colonography: Proof of concept”, Radiological Society of North America 90th Scientific Sessions, November 2004. - S. Liapis,
**E. Sifakis**and G. Tziritas, “Color and texture segmentation using wavelet frame analysis, deterministic relaxation and fast marching algorithms”, Journal of Visual Communication and Image Representation, 15:1, pp. 1-26, March 2004. [PDF] **E. Sifakis**and G. Tziritas, “Robust object boundary determination using a locally adaptive level set algorithm”, Intl. Conference on Image Processing, 2003 [PDF]**E. Sifakis**and G. Tziritas, “Fast Marching techniques for Visual Grouping”, in Geometric Level Set Methods in Imaging, Vision and Graphics, by S. Osher and N. Paragios (eds), Springer Verlag, July 2003**E. Sifakis**, C. Garcia and G. Tziritas, “Bayesian level sets for image segmentation”, Journal of Visual Communication and Image Representation, 13:1-2, pp. 44-64, March 2002 [PDF]**E. Sifakis**, I. Grinias and G. Tziritas, “Video segmentation using fast marching and region growing algorithms”, EURASIP Journal on Applied Signal Processing, pp. 379-388, Apr 2002 [PDF]**E. Sifakis**and G. Tziritas, “Moving object localization using a multi-label fast marching algorithm”, Signal Processing: Image Communication, 16:10, pp. 963-976, 2001 [PDF]**E. Sifakis**, I. Grinias and G. Tziritas, “Video segmentation using fast marching and region growing algorithms”, 3rd European Workshop on Image Analysis for Multimedia Interactive Services, 2001 (invited) [PDF]- S. Liapis,
**E. Sifakis**and G. Tziritas, “Color and/or texture segmentation using deterministic relaxation and fast marching algorithms”, Intl. Conference on Pattern Recognition, 2000 [PDF] **E. Sifakis**and G. Tziritas, “Fast marching to moving object location”, Intl. Conference on Scale-Space Theories in Computer Vision, 1999 [PDF]

Technical reports

- A. McAdams, A. Selle, R. Tamstorf, J. Teran and
**E. Sifakis**, “Computing the Singular Value Decomposition of 3x3 matrices with minimal branching and elementary floating point operations”, University of Wisconsin - Madison technical report TR1690, May 2011 [PDF] [Source Code]

Personal information

My wife, Demetra Makris Sifakis, is a dentist. Prior to our move to Madison she was working at the St. Johns Well Child and Family Center. She was also visiting clinical faculty for the UCLA School of Dentistry.