4 citations · 5 across the 8 of their papers we have counts for
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Box constraints and weighted sparsity regularization for identifying sources in elliptic PDEs
Ole Løseth Elvetun, Bjørn Fredrik Nielsen
We explore the possibility for using boundary data to identify sources in elliptic PDEs. Even though the associated forward operator has a large null space, it turns out that box c…
Numerical approximation of the spectrum of self-adjoint continuously invertible operators
Tomáš Gergelits, Bjørn Fredrik Nielsen, Zdeněk Strakoš
This paper deals with the generalized spectrum of continuously invertible linear operators defined on infinite dimensional Hilbert spaces. More precisely, we consider two bounded,…
Weighted sparsity regularization for source identification for elliptic PDEs
Ole Løseth Elvetun, Bjørn Fredrik Nielsen
This investigation is motivated by PDE-constrained optimization problems arising in connection with electrocardiograms (ECGs) and electroencephalography (EEG). Standard sparsity re…
Laplacian preconditioning of elliptic PDEs: Localization of the eigenvalues of the discretized operator
Tomáš Gergelits, Kent-André Mardal, Bjørn Fredrik Nielsen +1
In the paper \textit{Preconditioning by inverting the {L}aplacian; an analysis of the eigenvalues. IMA Journal of Numerical Analysis 29, 1 (2009), 24--42}, Nielsen, Hackbusch and T…