Uri Publications

Publications
Uri M. Ascher

E. Chen, S. Sheen, U. Ascher and D. Pai, ACM TOG 40 (Issue 1, Article 3), 1-12 (2020), DOI: 10.1145/3410527 :
SIERE: a hybrid semi-implicit exponential integrator for efficiently simulating stiff deformable objects
See also video clip at https://www.cs.ubc.ca/~ascher/papers/csap.m4v

U. Ascher, J. Dynamics and Games 7(2), 123-140 (2020), DOI: 10.3934/jdg.2020008 arXiv1910.02098:
Discrete processes and their continuous limits

E. Chen, D. Levin, D. Kaufman, U. Ascher and D. Pai, Proceedings SCA (2019), ACM, DOI: 10.1145/3309486.3340248 :
EigenFit for Consistent Elastodynamic Simulation Across Mesh Resolution
See also video clip at https://www.youtube.com/watch?v=aIAKBsT96to&feature=youtu.be

U. Ascher and H. Huang, Vietnam J. Math (Aug. 2018), DOI: 10.1007/s10013-018-0299-6:
Numerical analysis in visual computing: what we can learn from each other

E. Chen, U. Ascher and D. Pai, IEEE Trans. Computer Graphics (2017):
Exponential Rosenbrock-Euler integrators for elstodynamic simulation

V. Albani, U. Ascher, X. Yang and J. Zubelli, Inverse Problems and Imaging 11, 799-823 (2017):
Data driven recovery of local volatility surfaces

K. Rothauge, E. Haber and U. Ascher, 2016, arXiv1610.02596:
The discrete adjoint method for exponential integration

V. Albani, U. Ascher and J. Zubelli, J. Computational Finance 21, 1-33, (2017).
Local volatility models in commodity markets and online calibration

K. Rothauge, E. Haber and U. Ascher, 2015, arXiv1312.0707:
Numerical computation of the gradient and the action of the Hessian for time-dependent PDE-constrained optimization problems

B. Wang, L. Wu, K. Yin, U. Ascher, L. Liu and H. Huang, ACM TOG 34(4) (Siggraph) (2015):
Deformation capture and modeling of soft objects

U. Ascher and F. Roosta-Khorasani, Vietnam J. Math. (2016):
Algorithms that satisfy a stopping criterion, probably

F. Roosta-Khorasani, G. Szekely and U. Ascher, SIAM/ASA J. Uncertainty Quantification 3 (2015), DOI: 10.1137/14096311X:
Assessing stochastic algorithms for large scale nonlinear least squares problems using extremal probabilities of linear combinations of gamma variables

H. Huang, K. Yin, M. Gong, D. Lischinski, D. Cohen-Or, U. Ascher and B. Chen, ACM Trans. Graphics 32(5) (SIGGRAPH Asia) (2013):
``Mind the gap'': tele-registration for structure-driven image completion
See also the project home page

F. Roosta-Khorasani, K. van den Doel and U. Ascher, ETNA 42, (2014), 177-196:
Data completion and stochastic algorithms for PDE inversion problems with many measurements

F. Roosta-Khorasani and U. Ascher, J. Found. of Comp. Math. (2014), DOI: 10.1007/s10208-014-9220-1 arXiv1308.2475:
Improved bounds on sample size for implicit matrix trace estimators

K. van den Doel, U. Ascher and E. Haber, in ``Large Scale Inverse Problems'', M. Cullen, M. Freitag, S. Kindernmann and R. Scheichl (Eds.), de Gryter (2013), 181-203:
The lost honour of l2-based regularization.

F. Roosta-Khorasani, K. van den Doel and U. Ascher, SIAM J. Scient. Comput., 36, s3-s22, (2014). DOI: 10.1137/130922756.
Stochastic algorithms for inverse problems involving PDEs and many measurements

H. Huang, S. Wu, M. Gong, D. Cohen-Or, U. Ascher and R. Zhang, ACM Trans. Graphics 32(1) (2013):
Edge-aware point set resampling

K. van den Doel and U. Ascher, SIAM J. Scient. Comput. (2012), DOI: 10.1137/110826692:
Adaptive and stochastic algorithms for EIT and DC resistivity problems with piecewise constant solutions and many measurements.

K. van den Doel and U. Ascher, J. Scientific Computing (2011), DOI10.1007/s10915-011-9521-3 :
The chaotic nature of faster gradient descent methods

K. van den Doel, U. Ascher and D. Pai, Inverse Problems 27 (2011), 025008:
Source localization in electromyography using the inverse potential problem

U. Ascher, J. Appl. Numer. Math. (2012), DOI: 10.1016/j.apnum.2012.06.025
Surprising computations

H. Huang, D. Li, R. Zhang, U. Ascher and D. Cohen-Or, ACM Trans. Graphics 28(5) (SIGGRAPH Asia) (2009):
Consolidation of unorganized point clouds for surface reconstruction
See also the project home page

K. van den Doel, U. Ascher and A. Leitao, J. Scient. Comput. 43 (2009), 44-66:
Multiple level sets for piecewise constant surface reconstruction in highly ill-posed problems

H. Huang and U. Ascher, Math. Vietnam J. Math. 42 (2014), 115-131:
Faster gradient descent and the efficient recovery of images

U. Ascher, K. van den Doel, H. Huang and B. F. Svaiter, M2AN 43 (2009), 689-708:
Gradient descent and fast artificial time integration

K. van den Doel, U. Ascher and D. Pai, Inverse Problems 24 (2008), 065010:
Computed myography: three dimensional reconstruction of motor functions from surface EMG data

H. Huang and U. Ascher, SIAM J. Scient. Comput. 31 (2008), 74-93:
Surface mesh smoothing, regularization and feature detection

K. van den Doel and U. Ascher, IEEE Trans. Audio, Speech and Language Processing16 (2008), 1163-1172:
Real-time numerical solution of Webster's equation on a non-uniform grid

K. van den Doel and U. Ascher, Inverse Problems 23 (2007), 1271-1288:
Dynamic level set regularization for large distributed parameter estimation problems

O. Dorn and U. Ascher, Proc. 23rd International Review of Progress in Applied Computational Electromagnetics ACES (2007), 1-6:
Shape reconstruction in 3D electromagnetic induction tomography using a level set technique

E. Haber, S. Heldmann and U. Ascher, Inverse Problems 23 (2007), 1659-1676:
Adaptive finite volume method for distributed non-smooth parameter identification

U. Ascher, H. Huang and K. van den Doel, BIT, 47 (2007), 3-25:
Artificial time integration

H. Huang and U. Ascher, Inverse Problems 24 (2008), 034003:
Fast Denoising of Surface Meshes with Intrinsic Texture
K. van den Doel and U. Ascher, J. Comp. Phys., 216 (2006), 707-723:
On level set regularization for highly ill-posed distributed parameter estimation problems
U. Ascher, E. Haber and H. Huang, SIAM J. Scient. Comput., 28 (2006), 339-358:
On effective methods for implicit piecewise smooth surface recovery
E. Boxerman and U. Ascher, Symp. Computer Animation (2004), 153-161:
Decomposing cloth
U. Ascher and R. McLachlan, J. Scient. Comput., 25 (2005), 83-104:
On symplectic and multisymplectic schemes for the KdV equation
U. Ascher and E. Haber, Symp. Inverse Problems, Design and Optimization 2004:
Computational methods for large distributed parameter estimation problems with possible discontinuities
U. Ascher and R. McLachlan, Applied Numerical Mathematics, 48 (2004), 255-269 :
Multisymplectic box schemes and the Korteweg-de Vries equation
U. Ascher and E. Boxerman, The Visual Computer, 19 (2003), 526-531:
On the modified conjugate gradient method in cloth simulation
E. Haber, U. Ascher and D. Oldenburg, Geophysics, 69 (2004), 1216-1228:
Inversion of 3D electromagnetic data in frequency and time domain using an inexact all-at-once approach
U. Ascher and E. Haber, ETNA, 18 (2003), 1-18:
A multigrid method for distributed parameter estimation problems
E. Haber and U. Ascher, Inverse Problems, 17 (2001), 1847-1864:
Preconditioned all-at-once methods for large, sparse parameter estimation problems
D. Aruliah and U. Ascher, SIAM J. Scient. Comput., 24 (2003), 702-718:
Multigrid preconditioning for time-harmonic Maxwell's equations in 3D
U. Ascher and E. Haber, Inverse Problems, 17 (2001), 571--590:
Grid refinement and scaling for distributed parameter estimation problems
D. Pai, U. Ascher and P. Kry, Proc. ICRA (2000):
Forward dynamics algorithms for multibody chains and contacts
E. Haber and U. Ascher, SIAM J. Scient. Comput., 22 (2001), 1943--1961:
Fast finite volume simulation of 3D electromagnetic problems with highly discontinuous coefficients
E. Haber, U. Ascher, D. Aruliah and D. Oldenburg, J. Comp. Phys., 163 (2000), 150-171:
Fast simulation of 3D electromagnetic problems using potentials
R. Spiteri, D. Pai and U. Ascher, IEEE Trans. Robotics & Automation 16 (2000), 135-145:
Programming and control of robots by means of differential algebraic inequalities
D. Aruliah, U. Ascher, E. Haber and D. Oldenburg, M3AS 11 (2001), 1-21:
A method for the forward modelling of 3D electromagnetic quasi-static problems
E. Haber, U. Ascher and D. Oldenburg, Inverse Problems 16 (2000), 1263-1280:
On Optimization Techniques for Solving Nonlinear Inverse Problems
U. Ascher, IMA Proc. on Dynamics of Algorithms, vol 118 (1999), 55-68:
DAEs that should not be solved
U. Ascher and S. Reich, Proc. Computational Molecular Dynamics, Springer Lecture Notes (1999), 281-296:
On Some Difficulties in Integrating Highly Oscillatory Hamiltonian Systems
U. Ascher and S. Reich, SIAM J. Scient. Comput. 21 (1999), 1045-1065:
The midpoint scheme and variants for Hamiltonian systems: advantages and pitfalls
U. Ascher and P. Lin, SIAM J. Scient. Comput. 21 (1999), 1244-1262:
Sequential Regularization Methods for simulating mechanical systems with many closed loops
D. Moulton, J. Morel and U. Ascher, SIAM J. Scient. Comput. 19 (1998), 185-205:
Approximate Schur complement preconditioning of the lowest order nodal discretizations
U. Ascher, S. Ruuth and R. Spiteri, Applied Numerical Mathematics, 25 (1997), 151-167:
Implicit-Explicit Runge-Kutta Methods for Time-Dependent Partial Differential Equations
U. Ascher, Numerical Algorithms 14 (1997), 1-23:
Stabilization of invariants of discretized differential systems
U. Ascher and P. Lin, SIAM J. Scient. Comput. 18 (1997), 160-181:
Sequential Regularization Methods for Nonlinear Higher Index DAEs
U. Ascher, D. Pai and B. Cloutier, Int. J. Robotics Res. 16 (1997), 749-758:
Forward dynamics, elimination methods, and formulation stiffness in robot simulation
U. Ascher, H. Chin, L. Petzold and S. Reich, J. Mech. Struct. Machines 23 (1995), 135-158:
Stabilization of constrained mechanical systems with DAEs and invariant manifolds
R. Spiteri, U. Ascher and D. Pai, Proceedings IEEE Robotics & Automation, Nagoya 1995, 2373-2380:
Numerical solution of differential systems with algebraic inequalities arising in robot programming
U. Ascher and P. Lin, SIAM J. Numer. Anal. 33 (1996), 1921-1940:
Sequential regularization methods for higher index DAEs with constraint singularities: I. Linear index-2 case
U. Ascher and L. Petzold, SIAM J. Numer. Anal. 32 (1995), 1635-1657:
The numerical solution of delay-differential-algebraic equations of retarded and neutral type
U. Ascher, S. Ruuth and B. Wetton, SIAM J. Numer. Anal. 32 (1995), 797-823:
Implicit-explicit methods for time-dependent PDE's
D. Sidilkover and U. Ascher, Comp. Appl. Math. (SBMAC) 14 (1995), 21-35:
A multigrid solver for the steady state Navier-Stokes equations using the pressure-Poisson formulation
U. Ascher, H. Chin and S. Reich, Numer. Math. 67 (1994), 131-149:
Stabilization of DAEs and invariant manifolds
U. Ascher and R. Spiteri, SIAM J. Scient. Comput. 15 (1994), 938-952:
Collocation software for boundary value differential-algebraic eqns
U. Ascher and P. Carter, SIAM J. Numer. Anal. 30 (1993) 102-115:
[Some pictures are missing for this one.]
A multigrid method for shape from shading

Here are references to my older papers, for which no electronic version is available as yet:

Ascher, U. and Petzold, L., ``Projected Collocation for Higher-Order Higher-Index Differential-Algebraic Equations'', J. Comp. Appl. Math. 43 (1992) 243--259.
Adams, S., Ascher, U., ``Using multigrid for semiconductor device simulation in 1-D'', Proc. Conf. on Computational Mathematics, S. Fatunla (Ed.), Ibadan University Press, 1992.
Ascher, U., Petzold, L., ``Projected Implicit Runge-Kutta methods for differential-algebraic equations'', SIAM J. Numer. Anal. 28 (1991), 1097--1120.
Ascher, U., Markowich, P., Pietra, P. and Schmeiser, C., ``A phase plane analysis of transonic solutions for the hydrodynamic semiconductor model'', Mathematical Models and Methods in Applied Sciences 1 (1991), 347--376.
Ascher, U., Chan, P., ``On parallel methods for boundary value ODEs'', J. Computing} 46 (1991), 1-17 .
Ascher, U., ``On symmetric schemes and differential-algebraic equations'', SIAM J. Scient. Stat. Comput. 10 (1989), 937-949.
Ascher, U., ``On numerical differential-algebraic problems with application to semiconductor device simulation'', SIAM J. Numer. Anal., 26 (1989), 517-538.
Ascher, U., Jacobs, J., ``On collocation implementation for singularly perturbed two-point problems'', SIAM J. Scien. Stat. Comput. 10 (1989), 533-549.
Ascher, U., Markowich, P. Schmeiser, C., Steinruck, H., Weiss, R., ``Conditioning of the steady state semiconductor device problem'', SIAM J. Appl. Math. 49 (1989), 165-185.
Ascher, U., Bader, G., ``A note on conditioning stability and collocation matrices'', J. Appl. Math. Comput. 31 (1989), 437-448.
Ascher, U., Mattheij, R.M.M., ``General framework, stability and error analysis for numerical stiff boundary value methods'', Numerische Mathematik, 54 (1988), 355-372.
Alon, A., Ascher, U., ``Model and solution strategy for placement of rectangular blocks in the Euclidean plane'', IEEE Trans. CAD/ICAS 7 (1988), 378-386.
Ascher, U., Markowich, P., Schmeiser, C., Steinruck, H., Weiss, R., ``On the conditioning of the steady state semiconductor device problem'', Proc. NUMOS I, J. Miller (Ed.), 1987. Also appeared as COMPEL 6 (1987), 19-23.
Ascher, U., Osborne, M., ``A note on solving nonlinear equations and the `natural' criterion function'', J. Optimization Th. Applic. 55 (1987), 147-152.
Bader, G., Ascher, U., ``A new basis implementation for a mixed order boundary value ODE solver'', SIAM J. Scient. Stat. Comput. 8 (1987), 483-500.
Ascher, U., Spudich, P., ``A hybrid collocation method for calculating complete theoretical seismograms in vertically varying media'', Geoph. J. of Roy. Astr. Soc. 86 (1986), 19-40.
Ascher, U., ``Collocation for two-point boundary value problems revisited'', SIAM J. Numer. Anal. 23 (1986), 596-609.
Ascher, U., Bader, G., ``Stability of collocation at Gaussian points'', SIAM J. Numer. Anal. 23 (1986), 412-422.
Alon, A., Ascher, U., ``A placement algorithm using potential directed forces'', Proc. IASTED Conf. on CAD and Applic., June 1985.
Ascher, U., ``On some difference schemes for singular singularly-perturbed boundary value problems'', Numerische Mathematik 46 (1985), 1-30.
Ascher, U., ``Two families of symmetric difference schemes for singular perturbation problems'', in Numerical Boundary Value ODEs, U. Ascher and R.D. Russell (Eds.), Birkhauser Boston, 1985, 173-191.
Ascher, U., Weiss, R., ``Collocation for singular perturbation problems II: Linear first order systems without turning points'', Math. Comp. 43 (1984), 157-187.
Ascher, U., Weiss, R., ``Collocation for singular perturbation problems III: Nonlinear problems without turning points'', SIAM J. Scient. Stat. Computing 5 (1984), 811-829.
Spudich, P., Ascher, U., ``Calculation of complete theoretical seismograms in vertically varying media using collocation methods'', Geoph. J. of Roy. Astr. Soc. 75 (1983), 101-124.
Ascher, U., Weiss, R., ``Collocation for singular perturbation problems I: First order systems with constant coefficients'', SIAM J. Numer. Anal. 20 (1983), 537-557.
Ascher, U., Pruess, S. and Russell, R.D., ``On spline basis selection for solving differential equations'', SIAM J. Numer. Anal. 20 (1983), 121-142.
Ascher, U., Russell, R.D., ``Reformulation of boundary value problems in standard form'', SIAM Review, 23 (1981), 238-254.
Ascher, U., Christiansen, J. and Russell, R.D., ``Collocation softare for boundary value ODE's'', package and companion paper. ACM Trans. Math. Software, 7 (1981), 209-222 and 223-229.
Ascher, U., Wan, F.Y.M., ``Numerical solutions for maximum sustainable consumption growth with a multi-grade exhaustible resource'', SIAM J. on Scientific and Statistical Computation, 1 (1980), 160-172.
Ascher, U., ``Solving boundary value problems with a spline-collocation code'', J. Comp. Phys. 34 (1980), 401-413.
Ascher, U., Christiansen, J. and Russell, R.D., ``COLSYS - A collocation code for boundary value problems'', Lecture notes Comp. Sc. 76, Springer Verlag (1979), 164-185.
Ascher, U., Christiansen, J. and Russell, R.D., ``A collocation solver for mixed order systems of boundary value problems'', Math. Comp. 33 (1979), 659-679.
Ascher, U., Rosen, J.B., ``A collocation method for parabolic quasilinear problems on general domains'', J. Comp. Appl. Math. 5 (1979), 183-191.
Ascher, U., ``Discrete least squares approximations for ordinary differential equations'', SIAM J. Numer. Anal. 15 (1978), 478-496.
Ascher, U., ``On the invariance of the interpolation points of the discrete $l_1 $-approximation'', J. Approx. Th. 24 (1978), 83-91.
Ascher, U., ``Linear programming algorithms for the Chebyshev solution to a system of consistent linear equations'', SIAM J. Numer. Anal. 14 (1977), 519-526.

Publications Uri M. Ascher

Publications
Uri M. Ascher