Bjørn Fredrik Nielsen

According to our database, Bjørn Fredrik Nielsen authored at least 25 papers between 1996 and 2024.

Collaborative distances:

• Dijkstra number of five.
• Erdős number of four.

2024

A Simple Formula for the Generalized Spectrum of Second Order Self-Adjoint Differential Operators.

Bjørn Fredrik Nielsen, Zdenek Strakos

SIAM Rev., February, 2024

Fictitious null spaces for improving the solution of injective inverse problems.

Ole Løseth Elvetun, Kim Knudsen, Bjørn Fredrik Nielsen

CoRR, 2024

2022

Numerical approximation of the spectrum of self-adjoint operators in operator preconditioning.

Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos

Numer. Algorithms, 2022

Box constraints and weighted sparsity regularization for identifying sources in elliptic PDEs.

Ole Løseth Elvetun, Bjørn Fredrik Nielsen

CoRR, 2022

2021

Numerical approximation of the spectrum of self-adjoint continuously invertible operators.

Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos

CoRR, 2021

2020

Generalized Spectrum of Second Order Differential Operators.

Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos

SIAM J. Numer. Anal., 2020

Sparsity regularization for inverse problems with nullspaces.

Ole Løseth Elvetun, Bjørn Fredrik Nielsen

CoRR, 2020

2019

Laplacian Preconditioning of Elliptic PDEs: Localization of the Eigenvalues of the Discretized Operator.

Tomás Gergelits, Kent-André Mardal, Bjørn Fredrik Nielsen, Zdenek Strakos

SIAM J. Numer. Anal., 2019

2016

PDE-Constrained Optimization with Local Control and Boundary Observations: Robust Preconditioners.

Ole Løseth Elvetun, Bjørn Fredrik Nielsen

SIAM J. Sci. Comput., 2016

The split Bregman algorithm applied to PDE-constrained optimization problems with total variation regularization.

Ole Løseth Elvetun, Bjørn Fredrik Nielsen

Comput. Optim. Appl., 2016

2014

Bidomain Simulations of Subendocardial Ischemia: The Forward and Inverse Problems.

Marius Lysaker, Bjørn Fredrik Nielsen, Samuel T. Wall

Proceedings of the Computing in Cardiology, CinC 2014, 2014

2013

Computing Ischemic Regions in the Heart With the Bidomain Model - First Steps Towards Validation.

Bjørn Fredrik Nielsen, Ola Marius Lysaker, Per Grottum

IEEE Trans. Medical Imaging, 2013

Analysis of the Minimal Residual Method Applied to Ill Posed Optimality Systems.

Bjørn Fredrik Nielsen, Kent-André Mardal

SIAM J. Sci. Comput., 2013

Computing Ischemic Regions in the Heart: On the Use of Internal Electrodes.

Ola Marius Lysaker, Bjørn Fredrik Nielsen, Samuel T. Wall

Proceedings of the Computing in Cardiology, 2013

Observability of Ischemia and the Need for Patient Specific Geometrical Models in Inverse ECG.

Glenn T. Lines, Marius Lysaker, Bjørn Fredrik Nielsen

Proceedings of the Computing in Cardiology, 2013

2010

Efficient Preconditioners for Optimality Systems Arising in Connection with Inverse Problems.

Bjørn Fredrik Nielsen, Kent-André Mardal

SIAM J. Control. Optim., 2010

Can ECG Recordings and Mathematics tell the Condition of Your Heart?

Bjørn Fredrik Nielsen, Marius Lysaker, Per Grøttum, Kent-André Mardal, Aslak Tveito, Christian Tarrou, Kristina Hermann Haugaa, Andreas Abildgaard, Jan Gunnar Fjeld

Proceedings of the Simula Research Laboratory, by Thinking Constantly about it, 2010

2009

A Computationally Efficient Method for Determining the Size and Location of Myocardial Ischemia.

Tomas Syrstad Ruud, Bjørn Fredrik Nielsen, Ola Marius Lysaker, Joakim Sundnes

IEEE Trans. Biomed. Eng., 2009

2007

An order optimal solver for the discretized bidomain equations.

Kent-André Mardal, Bjørn Fredrik Nielsen, Xing Cai, Aslak Tveito

Numer. Linear Algebra Appl., 2007

A note on the efficiency of the conjugate gradient method for a class of time-dependent problems.

Xing Cai, Bjørn Fredrik Nielsen, Aslak Tveito

Numer. Linear Algebra Appl., 2007

On the use of the resting potential and level set methods for identifying ischemic heart disease: An inverse problem.

Bjørn Fredrik Nielsen, Marius Lysaker, Aslak Tveito

J. Comput. Phys., 2007

Optimal monodomain approximations of the bidomain equations.

Bjørn Fredrik Nielsen, Tomas Syrstad Ruud, Glenn Terje Lines, Aslak Tveito

Appl. Math. Comput., 2007

2006

Computing the size and location of myocardial ischemia using measurements of ST-segment shift.

Mary C. MacLachlan, Bjørn Fredrik Nielsen, Ola Marius Lysaker, Aslak Tveito

IEEE Trans. Biomed. Eng., 2006

1997

On the Approximation of the Solution of the Pressure Equation by Changing the Domain.

Aslak Tveito, Bjørn Fredrik Nielsen

SIAM J. Appl. Math., 1997

1996

On the Stability of Pressure and Velocity Computations for Heterogeneous Reservoirs.

Are Magnus Bruaset, Bjørn Fredrik Nielsen

SIAM J. Appl. Math., 1996