Bjørn Fredrik Nielsen

29 papers Journal 25Unranked 3

Year	Rank	Type	Title / Venue / Authors
2026	J	`jnl`	Estimating Neural Connection Strengths from Firing Intervals. SIAM J. Appl. Math. Maren B. Kristoffersen, Bjørn Fredrik Nielsen, Susanne Solem
2025	J	`jnl`	Weighted Group Lasso for a static EEG problem. CoRR Ole Løseth Elvetun, Bjørn Fredrik Nielsen, Niranjana Sudheer
2025	J	`jnl`	Weighted total variation regularization for inverse problems with significant null spaces. CoRR Martin Burger, Ole Løseth Elvetun, Bjørn Fredrik Nielsen
2025	J	`jnl`	Weighting operators for sparsity regularization. CoRR Ole Løseth Elvetun, Bjørn Fredrik Nielsen, Niranjana Sudheer
2024	J	`jnl`	A Simple Formula for the Generalized Spectrum of Second Order Self-Adjoint Differential Operators. SIAM Rev. Bjørn Fredrik Nielsen, Zdenek Strakos
2024	J	`jnl`	Fictitious null spaces for improving the solution of injective inverse problems. CoRR Ole Løseth Elvetun, Kim Knudsen, Bjørn Fredrik Nielsen
2022	J	`jnl`	Box constraints and weighted sparsity regularization for identifying sources in elliptic PDEs. CoRR Ole Løseth Elvetun, Bjørn Fredrik Nielsen
2022	J	`jnl`	Numerical approximation of the spectrum of self-adjoint operators in operator preconditioning. Numer. Algorithms Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos
2021	J	`jnl`	Numerical approximation of the spectrum of self-adjoint continuously invertible operators. CoRR Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos
2020	J	`jnl`	Generalized Spectrum of Second Order Differential Operators. SIAM J. Numer. Anal. Tomás Gergelits, Bjørn Fredrik Nielsen, Zdenek Strakos
2020	J	`jnl`	Sparsity regularization for inverse problems with nullspaces. CoRR Ole Løseth Elvetun, Bjørn Fredrik Nielsen
2019	J	`jnl`	Laplacian Preconditioning of Elliptic PDEs: Localization of the Eigenvalues of the Discretized Operator. SIAM J. Numer. Anal. Tomás Gergelits, Kent-André Mardal, Bjørn Fredrik Nielsen, Zdenek Strakos
2016	J	`jnl`	PDE-Constrained Optimization with Local Control and Boundary Observations: Robust Preconditioners. SIAM J. Sci. Comput. Ole Løseth Elvetun, Bjørn Fredrik Nielsen
2016	J	`jnl`	The split Bregman algorithm applied to PDE-constrained optimization problems with total variation regularization. Comput. Optim. Appl. Ole Løseth Elvetun, Bjørn Fredrik Nielsen
2014	—	`conf`	Bidomain Simulations of Subendocardial Ischemia: The Forward and Inverse Problems. CinC Marius Lysaker, Bjørn Fredrik Nielsen, Samuel T. Wall
2013	J	`jnl`	Analysis of the Minimal Residual Method Applied to Ill Posed Optimality Systems. SIAM J. Sci. Comput. Bjørn Fredrik Nielsen, Kent-André Mardal
2013	J	`jnl`	Computing Ischemic Regions in the Heart With the Bidomain Model - First Steps Towards Validation. IEEE Trans. Medical Imaging Bjørn Fredrik Nielsen, Ola Marius Lysaker, Per Grottum
2013	—	`conf`	Computing Ischemic Regions in the Heart: On the Use of Internal Electrodes. CinC Ola Marius Lysaker, Bjørn Fredrik Nielsen, Samuel T. Wall
2013	—	`conf`	Observability of Ischemia and the Need for Patient Specific Geometrical Models in Inverse ECG. CinC Glenn T. Lines, Marius Lysaker, Bjørn Fredrik Nielsen
2010	—	`ch.`	Can ECG Recordings and Mathematics tell the Condition of Your Heart? Simula Research Laboratory Bjørn Fredrik Nielsen, Marius Lysaker, Per Grøttum, Kent-André Mardal, Aslak Tveito, Christian Tarrou, Kristina Hermann Haugaa, Andreas Abildgaard, Jan Gunnar Fjeld
2010	J	`jnl`	Efficient Preconditioners for Optimality Systems Arising in Connection with Inverse Problems. SIAM J. Control. Optim. Bjørn Fredrik Nielsen, Kent-André Mardal
2009	J	`jnl`	A Computationally Efficient Method for Determining the Size and Location of Myocardial Ischemia. IEEE Trans. Biomed. Eng. Tomas Syrstad Ruud, Bjørn Fredrik Nielsen, Ola Marius Lysaker, Joakim Sundnes
2007	J	`jnl`	A note on the efficiency of the conjugate gradient method for a class of time-dependent problems. Numer. Linear Algebra Appl. Xing Cai, Bjørn Fredrik Nielsen, Aslak Tveito
2007	J	`jnl`	An order optimal solver for the discretized bidomain equations. Numer. Linear Algebra Appl. Kent-André Mardal, Bjørn Fredrik Nielsen, Xing Cai, Aslak Tveito
2007	J	`jnl`	On the use of the resting potential and level set methods for identifying ischemic heart disease: An inverse problem. J. Comput. Phys. Bjørn Fredrik Nielsen, Marius Lysaker, Aslak Tveito
2007	J	`jnl`	Optimal monodomain approximations of the bidomain equations. Appl. Math. Comput. Bjørn Fredrik Nielsen, Tomas Syrstad Ruud, Glenn Terje Lines, Aslak Tveito
2006	J	`jnl`	Computing the size and location of myocardial ischemia using measurements of ST-segment shift. IEEE Trans. Biomed. Eng. Mary C. MacLachlan, Bjørn Fredrik Nielsen, Ola Marius Lysaker, Aslak Tveito
1997	J	`jnl`	On the Approximation of the Solution of the Pressure Equation by Changing the Domain. SIAM J. Appl. Math. Aslak Tveito, Bjørn Fredrik Nielsen
1996	J	`jnl`	On the Stability of Pressure and Velocity Computations for Heterogeneous Reservoirs. SIAM J. Appl. Math. Are Magnus Bruaset, Bjørn Fredrik Nielsen