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Università della Svizzera italiana

Space–time shape uncertainties in the forward and inverse problem of electrocardiography

Gander, Lia ; Krause, Rolf ; Multerer, Michael ; Pezzuto, Simone

In: International journal for numerical methods in biomedical engineering, 2021, vol. 37, no. 10, p. 23

In electrocardiography, the “classic” inverse problem is the reconstruction of electric potentials at a surface enclosing the heart from remote recordings at the body surface and an accurate description of the anatomy. The latter being affected by noise and obtained with limited resolution due to clinical constraints, a possibly large uncertainty may be perpetuated in the inverse ...

Università della Svizzera italiana

Large scale simulation of pressure induced phase-field fracture propagation using Utopia

Zulian, Patrick ; Kopaničáková, Alena ; Nestola, Maria Giuseppina Chiara ; Fink, Andreas ; Fadel, Nur Aiman ; VandeVondele, Joost ; Krause, Rolf

In: CCF transactions on high performance computing, 2021, no. 3, p. 407–426

Non-linear phase field models are increasingly used for the simulation of fracture propagation problems. The numerical simulation of fracture networks of realistic size requires the efficient parallel solution of large coupled non-linear systems. Although in principle efficient iterative multi-level methods for these types of problems are available, they are not widely used in practice due to...

Università della Svizzera italiana

GEASI : Geodesic-based earliest activation sites identification in cardiac models

Grandits, Thomas ; Effland, Alexander ; Pock, Thomas ; Krause, Rolf ; Plank, Gernot ; Pezzuto, Simone

In: International journal for numerical methods in biomedical engineering, 2021, vol. 37, no. 8, p. 30

The identification of the initial ventricular activation sequence is a critical step for the correct personalization of patient- specific cardiac models. In healthy conditions, the Purkinje network is the main source of the electrical activation, but under pathological conditions the so-called earliest activation sites (EASs) are possibly sparser and more localized. Yet, their number, location...

Università della Svizzera italiana

An experimental comparison of a space-time multigrid method with PFASST for a reaction-diffusion problem

Benedusi, Pietro ; Minion, Michael L. ; Krause, Rolf

In: Computers and mathematics with applications, 2021, vol. 99, p. 162-170

We consider two parallel-in-time approaches applied to a (reaction) diffusion problem, possibly non-linear. In particular, we consider PFASST (Parallel Full Approximation Scheme in Space and Time) and space-time multigrid strategies. For both approaches, we start from an integral formulation of the continuous time dependent problem. Then, a collocation form for PFASST and a discontinuous ...

Università della Svizzera italiana

Space-time multilevel Monte Carlo methods and their application to cardiac electrophysiology

Ben Bader, Seif ; Benedusi, Pietro ; Quaglino, Alessio ; Zulian, Patrick ; Krause, Rolf

In: Journal of computational physics, 2021, vol. 433, p. 17 p

We present a novel approach aimed at high-performance uncertainty quantification for time-dependent problems governed by partial differential equations. In particular, we consider input uncertainties described by a Karhunen-Loève expansion and compute statistics of high-dimensional quantities-of-interest, such as the cardiac activation potential. Our methodology relies on a close integration...

Università della Svizzera italiana

Leukocyte tracking database, a collection of immune cell tracks from intravital 2-photon microscopy videos

Pizzagalli, Diego Ulisse ; Farsakoglu, Yagmur ; Palomino-Segura, Miguel ; Palladino, Elisa ; Sintes, Jordi ; Marangoni, Francesco ; Mempel, Thorsten R. ; Koh, Wan Hon ; Murooka, Thomas T. ; Thelen, Flavian ; Stein, Jens V. ; Pozzi, Giuseppe ; Marcus Thelen ; Krause, Rolf ; Gonzalez, Santiago Fernandez

In: Scientific data, 2018, vol. 5, p. 180129

Recent advances in intravital video microscopy have allowed the visualization of leukocyte behavior in vivo, revealing unprecedented spatiotemporal dynamics of immune cell interaction. However, state-of-the-art software and methods for automatically measuring cell migration exhibit limitations in tracking the position of leukocytes over time. Challenges arise both from the complex migration...

Consortium of Swiss Academic Libraries

Evaluating Local Approximations of the L 2-Orthogonal Projection Between Non-Nested Finite Element Spaces

Dickopf, Thomas ; Krause, Rolf

In: Numerical Mathematics: Theory, Methods and Applications, 2014, vol. 7, no. 3, p. 288-316