# Karl Hollaus

# Dr. techn. Karl Hollaus

## AddressInstitute for Analysis and Scientific Computing <br\> Wiedner Hauptstrasse 8-10 <br\> 1040 Wien, Austria Tel: +43 1 58801 10116 <br\> Email: karl.hollaus@tuwien.ac.at |

#### Research Interests

Computational Electromagnetics, Finite Element Method, Domain Decomposition, Homogenization, Software Development (netgen)<br\>

#### Diploma Thesis

*Identifikation optimaler Geometrieparameter einer SMES - Spulenanordnung mit deterministischen und stochastischen Optimierungsverfahren*, TU Graz and Dipartimento di Ingegneria Elettrica, Università degli Studi di Genova, 1997.

#### PhD Thesis

*Numerical Simulation of Eddy Currents and the Associated Losses in Laminated Ferromagnetic Materials by the Method of Finite Elements*, TU Graz, 2001. pdf

#### Talks

*Homogenization of the Eddy Current Problem in 2D*, 14th International IGTE Symposium 2010, Graz, Sept. 19 - 22, 2010. pdf

*Novel Variation Formulation for Domain Decomposition to solve Maxwell's Equations*, DSPDES 2010, Barcelona, June 3, 2010. pdf

#### Recent work

*Two-scale FEM for the linear Eddy Current Problem in 3D*, Digest for Compumag 2011(submitted, Dec., 2010)
preprint

#### Publications

- K. Hollaus, J. Schöberl, "Homogenization of the Eddy Current Problem in 2D," (submitted, Oct., 2010) preprint
- K. Hollaus, D. Feldengut, J. Schöberl, M. Wabro, D. Omeragic, "Nitsche-type Mortaring for Maxwell's Equations," (submitted, March, 2010) preprint
- K. Hollaus, O. Bíró, P. Caldera, G. Matzenauer, G. Paoli, K. Preis, C. Stockreiter, "Extraction of Circuit Parameters from PCBs by FDTD and SIBC," COMPEL, vol. 28, no. 4, pp. 1091-1101, 2009.
- K. Hollaus, O. Bíró, P. Caldera, G. Matzenauer, G. Paoli, and G. Plieschenegger, "Simulation of Crosstalk on Printed Circuit Boards by FDTD, FEM and a Circuit Model," IEEE Transactions on Magnetics, vol. 44, pp. 1486-1489, April 2008.
- K. Hollaus, O. Bíró, K. Preis and C. Stockreiter, "Edge finite elements coupled with a circuit for wave problems," Internat. Conf. on Electromagnetics in Advanced Applications, ICEAA 2007, IEEE Xplore, pp. 956-959, Torino, Italy, 17th –21st Sept. 2007.
- B. Weiß, O. Bíró, P. Caldera, K. Hollaus, G. Paoli, K. Preis, "A Multigrid Algorithm for the Transfinite-Element Time-Domain Method using the A, V Formulation", IEEE Transactions on Magnetics, vol. 43, pp. 1353-1356, April 2007.
- C. Stockreiter, O. Bíró, K. Hollaus, K. Preis and B. Weiß, "Transfinite Element Method using the A, v –Potential Formulation with Edge-Elements in the Frequency Domain," IEEE Transactions on Magnetics, vol. 43, pp. 1349-1352, April 2007.
- W. Renhart, K. Hollaus, C. Magele and G. Matzenauer, "Radiation of USB-WLAN Aantenna Influenced by Human Tissue and by Notebook Enclosure," IEEE Transactions on Magnetics, vol. 43, pp. 1345-1348, April 2007.
- G. Matzenauer, O. Bíró, K. Hollaus, K. Preis, W. Renhart, "Perfectly Matched Layers for T, Phi Formulation," COMPEL, vol. 26, no. 3, pp. 612-625, 2007.
- H. Scharfetter, K. Hollaus, J. Rosell-Ferrer, R. Merwa, "Single-step 3-D image reconstruction in magnetic induction tomography: Theoretical limits of spatial resolution and contrast to noise ratio," Annals of Biomedical Engineering, pp. 1-13, 2006.
- K. Hollaus, O. Bíró, P. Caldera, G. Matzenauer, G. Paoli, K. Preis, W. Renhart, C. Stockreiter and B. Weiß, "Simulation of Microstrips on Printed Circuit Boards," Tagungsband des 51. Internationalen Wissenschaftliches Kolloquium der TU Ilmenau, ISBN 3-938843-16-0, 5 pages, Ilmenau, Germany, 11-15, September 2006.
- K. Hollaus, O. Bíró, K. Preis, C. Stockreiter and B. Weiß, "S-Parameter Extraction from Structures on Printed Circuit Boards by FDTD and Surface Impedance Boundary Condition," Proceedings of The Twelfth IEEE Conference on Electromagnetic Field Computation, ISBN 1-4244-0319-7, p. 378, Miami, USA, April 30th-May 3rd, 2006.
- K. Hollaus, O. Bíró, G. Matzenauer, K. Preis, C. Stockreiter, B. Weiß, P. Caldera and G. Paoli, "Comparison of FETD and FDTD to Simulate Micro-strip Structures on PCBs," Proceedings of The Sixth International Conference on Computation in Electromagnetics CEM 2006, ISBN 3-8007-2957-1, p. 209-210, Aachen, Germany, April 4-6, 2006.
- B. Wagner, K. Hollaus, Ch. Magele, "Reconstruction of the anisotropic complex conductivity distribution of a human thigh in three dimensions," IEEE Transactions on Magnetics, vol. 42, pp. 1171-1174, April 2006.
- K. Hollaus, O. Bíró, P. Caldera, G. Matzenauer, G. Paoli, K. Preis and B. Weiss, "Electromagnetic Field Computation of Simple Structures on Printed Circuit Boards by the Finite Element Method," IEEE Transactions on Magnetics, vol. 42, pp. 815-818, April 2006.
- B. Weiß, O. Bíró, K. Hollaus, K. Preis, P. Caldera, G. Paoli, "A Multigrid Solver for Time Harmonic 3D Electromagnetic Wave Problems," IEEE Transactions on Magnetics, vol. 42, pp. 639-642, April 2006.
- K. Hollaus, B. Wagner, O. Bíró, "Simulation of the quasi-static electric field by an electric current vector potential approximated by edge elements", COMPEL, vol. 24, no. 2, pp. 581-590, 2005.
- B. Wagner, K. Hollaus, Ch. Magele, "Reconstruction of the anisotropic complex conductivity distribution in 3D", COMPEL, vol. 24, no. 2, pp. 558-564, 2005.
- K. Hollaus, O. Bíró, P. Caldera, G. Matzenauer, G. Paoli, K. Preis, B. Weiss, "Simulation of Simple Topologies on a PCB by a Frequency and a Time Domain Method," Proceedings of Joint 9th ICEAA `05 and 11th EESC `05, Torino, Italy, 12th Sept. – 16th Sept. 2005, ISBN 88-8202-094-0, pp. 893-896.
- K. Hollaus, O. Bíró, "Comparison of tetrahedral edge finite elements using different potential formulations,” IEEE Transactions on Magnetics, vol. 41, pp. 1676-1679, May 2005.
- K. Hollaus, O. Bíró, C. Gerstenberger, K. Preis, R. Stollberger, B. Wagner, "Effect of Stray Capacitances on Bio-Impedances in Quasi-Static Electric Field,” IEEE Transactions on Magnetics, vol. 41, pp. 1940-1943, May 2005.
- R. Merwa, K. Hollaus, P. Brunner, H. Scharfetter, "Solution of the inverse problem of magnetic induction tomography (MIT)", Physiol. Meas., vol. 26, no. 2, pp. S241-S250, April 2005.
- K. Hollaus, C. Gerstenberger, C. Magele, H. Hutten, "Accurate Reconstruction Algorithm of the Complex Conductivity Distribution in Three Dimensions," IEEE Transactions on Magnetics, vol. 40, pp. 1144-1147, March 2004.
- K. Hollaus, C. Magele, R. Merwa, H. Scharfetter, "Numerical Simulation of the Eddy Current Problem in Magnetic Induction Tomography for Biomedical Applications by Edge Elements,” IEEE Transactions on Magnetics, vol. 40, pp. 623-626, March 2004.
- R. Casañas, H. Scharfetter, A. Altes, A. Remacha, P. Sarda, J. Sierra, R. Merwa, K. Hollaus, J. Rosell, "Measurement of liver iron overload by magnetic induction using a planar gradiometer: preliminary human results", Physiol. Meas., vol. 25, no. 1, pp. 315-323, February 2004.
- R. Merwa, K. Hollaus, O. Bíró, H. Scharfetter, "Detection of brain oedema using magnetic induction tomography: A feasibility study of the likely sensitivity and detectability", Physiol. Meas., vol. 25, no. 1, pp. 347-354, February 2004.
- H. Scharfetter, S. Rauchenzauner, R. Merwa, O. Bíró, K. Hollaus, "Planar gradiometer for magnetic induction tomography (MIT): theoretical and experimental sensitivity maps for a low-contrast phantom", Physiol. Meas., vol. 25, no. 1, pp. 325-333, February 2004.
- K. Hollaus, B. Weiß, Ch. Magele, H. Hutten, "Geometric multigrid to accelerate the solution of the quasi-static electric field problem by tetrahedral finite elements", Physiol. Meas., vol. 25, no. 1, pp. 169-179, February 2004.
- K. Hollaus, C. Magele, R. Merwa, H. Scharfetter, "Fast calculation of the sensitivity matrix in magnetic induction tomography by tetrahedral edge finite elements and the reciprocity theorem", Physiol. Meas., vol. 25, no. 1, pp. 159-168, February 2004.
- R. Casañas, H. Scharfetter, A. Altes, A. Remacha, P. Sarda, J. Sierra, R. Merwa, K. Hollaus, J. Rosell, "In-vitro and in-vivo measurement of iron concentration in human hepatic tissue by magnetic induction methods," Proc. 25th Annual Int. Conf. IEEE, Eng. in Med. and Biol. Society, vol. 4, pp. 3064-3067, Sept. 2003.
- K. Hollaus, R. Stollberger, B. Wagner, C. Gerstenberger, Ch. Magele, H. Hutten, "Simulations of the bio-impedance of the human thigh by the finite element method in 3D", Tagungsband des 48. Internationalen Wissenschaftliches Kolloquium der TU Ilmenau, ISSN 1619-4098, pp. 425-426, Ilmenau, Germany, 22-25, September 2003.
- R. Merwa, K. Hollaus, B. Brandstätter, H. Scharfetter, "Numerical solution of the general 3D eddy current problem for magnetic induction tomography (spectroscopy)", Physiol. Meas., vol. 24, no. 2, pp. 545-554, May 2003.
- B. Brandstätter, K. Hollaus, Ch. Magele, M. Michael, R. Merwa, H. Scharfetter, H. Hutten, "Direct estimation of Cole parameters in multifrequency EIT using a regularized Gauss-Newton method", Physiol. Meas., vol. 24, no. 2, pp. 437-448, May 2003.
- K. Hollaus, O. Bíró, B. Brandstätter, S. P. Cermak, H. Zangl, G. Brasseur, "Design and Optimization of a Multi-Induction-Loop Access Control System", Proceedings of the International Symposium on Electromagnetic Compatibility, EMC Europe 2002, vol. 2, pp. 883-888, Sorrent, Italy, September 9-13, 2002.
- K. Hollaus, O. Bíró, "Derivation of a Complex Permeability from the Preisach Model," IEEE Transactions on Magnetics, vol. 38, pp. 905-908, March 2002.
- D. Rodger, P. C. Coles, O. Bíró, K. Hollaus, J. Pávó, "An Aluminum Plate Benchmark for ECT", in Electromagnetic Nondestructive Evaluation (V), eds. J. Pávó et al, IOS Press, Amsterdam, vol. 21, pp. 46-48, 2001.
- O. Bíró, K. Hollaus, J. Pávó and K. Preis, "Numerical computation of the magnetic field due to a crack in a conducting plate", in Electromagnetic Nondestructive Evaluation (V), eds. J. Pávó et al, IOS Press, Amsterdam, vol. 21, pp. 11-15, 2001.
- J. Pávó, O. Bíró, K. Hollaus, "Calculation of the field map from the measurement data of the fluxset sensor", COMPEL, vol. 20, no. 2, pp. 404-416, 2001.
- K. Hollaus, O. Bíró, "A FEM of the Eddy Current Losses in Thin Ferromagnetic Sheets", Proceedings of the 9th International IGTE Symposium on Numerical Field Calculation in Electrical Engineering, pp. 152-157, Graz, Austria, September 11-13, 2000.
- K. Hollaus, O. Bíró, "A FEM Formulation to Treat 3D Eddy Currents in Laminations," IEEE Transactions on Magnetics, vol. 36, pp. 1289-1292, July 2000.
- D. Rodger, P. C. Coles, O. Bíró, K. Hollaus, J. Pávó, "An Aluminum Plate Benchmark for ECT", in Short Papers of The Sixth International Workshop on Electromagnetic Nondestructive Evaluation, ISBN 9-634206-42-5, Budapest, Hungary, pp. 39-40, 28th-30th July, 2000.
- O. Bíró, K. Hollaus, J. Pávó and K. Preis, "Numerical computation of the magnetic field due to a crack in a conducting plate", in Short Papers of The Sixth International Workshop on Electromagnetic Nondestructive Evaluation, ISBN 9-634206-42-5, Budapest, Hungary, pp. 7-8, 28th-30th July, 2000.
- K. Hollaus, O. Bíró, "Estimation of 3D eddy currents in conducting laminations by an anisotropic conductivity and a 1D analytical solution", COMPEL, vol. 18, no. 3, pp. 494-503, 1999.