Fleurianne Bertrand

TU Chemnitz
Numerical analysis and Optimisation

International Workshop Held for Leszek Demkowicz’s 70th Birthday

Austin, USA
April 11th, 2023 

Guests from around the globe gathered for a celebratory workshop on April 11 in honor of Leszek Demkowicz’s 70th Birthday, hosted by the Oden Institute for Computational Engineering and Sciences at The University of Texas at Austin. Speakers shared research and words of appreciation for Demkowicz’s contributions in the fields of computational mathematics and mechanics and beyond.
Here is the summary from the ODEN Institute

In addition, CAMWA plans to publish a special issue on the occasion of the Workshop in Honor of Leszek Demkowicz's 70th Birthday, as Leszek has been the Editor in Chief of CAMWA from 2012 to 2018. He completely redesigned the journal with great effort and success. The special issue in his honor is a recognition of his great contribution to our community and a nice memory of his commitment to our journal. I have the great honor to be the managing guest editor of this special issue, where all the managing editors (excluding Leszek) and the former managing editor Norbert Heuer are the guest editors.

Minimum Residual & Least-Squares Finite Element Methods

Santiago, Chile
5-7 October 2022 

The aim of this workshop is to bring together leading international researchers in the area of minimum residual and least-squares finite element methods. This is the fifth edition and takes place Oct. 5-7, 2022 at the Pontifical Catholic University of Chile in Santiago, Chile. The first workshop in this series took place 2013 in Austin, followed by the second workshop 2015 in Delft, the third one 2017 in Portland, and the fourth one 2019 in Berlin.


My talk in the minisymposium Advanced HPC Methods for Eigenvalue Problems and Beyond organized by Ali Hashemian, David Pardo, Victor Calo, Carla Manni and Quanling Deng won the first-place of WCCM IACM-FRC Best Presentation award

Starry Night Award winner

8th European Congress on Computational Methods in Applied Sciences and Engineering
5-9 June 2022, Oslo, Norway 

Presentation in pairs in the Young Researcher mini Symposium together with Maximilian Brodbeck
I am also the winner of the ECCOMAS22 Arts and Science competition

34th FE Symposium 2021 

Special focus on: Inverse Problems, Discontinuous Galerkin Methods, Nonlinear PDE's, Adaptivity

Sea Ice Antarctica cruise mixed finite elements
Oberwolfach, April 2021: Numerical Analysis of Electromagnetic Problems 

(Co-organisation with Matthias Schlottbom and Gerhard Starke)
The aim of this small-scale, week-long interactive mini-workshop jointly organized by the University of Duisburg-Essen and the University of Twente, and kindly hosted at the MFO, is to bring together experts in non-standard and mixed finite elements methods with experts in the field of electromagnetism.

Sea Ice Antarctica cruise mixed finite elements
Oberwolfach Workshop, January 2021: Nonstandard FEM

Abstract: Finite element methodologies dominate the computational approaches for the solution to partial differential equations and nonstandard finite element schemes most urgently require mathematical insight in their design. The hybrid workshop vividly enlightened and discussed innovative nonconforming and polyhedral methods, discrete complex-based finite element methods for tensor-problems, fast solvers and adaptivity, as well as applications to challenging ill-posed and nonlinear problems.

Sea Ice Antarctica cruise mixed finite elements
Oberwolfach Workshop, september 2019: Innovative Approaches to the Numerical Approximation of PDEs 

This workshop was about the numerical solution of PDEs for which classical approaches, such as the finite element method, are not well suited or need further (theoretical) underpinnings. 

Sea Ice Antarctica cruise mixed finite elements
Invited plenary speaker at FEM Symposium on Tour 2019 

I was invited to talk about the new results on Least-Squares methods for the approximation of Eigenvalues

Sea Ice Antarctica cruise mixed finite elements
Minimum Residual and Least-Squares Finite Element Methods in Berlin 

We are organizing this workshop Least-Squares Finite Element Methods and Discontinuous Petrov Galerkin Methods at HU Berlin from September 16th to September 18th, 2019. 

Sea Ice Antarctica cruise mixed finite elements
7th Sino-German Symposium on Computational and Applied Mathematics August 19 - 23, 2019  

Corresponding special issue

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SPP Annual Meeting, Bad Honnef, 01 - 03 July 2019  

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Minisymposium at ICIAM, jointly organised with Markus Weimar (Ruhr Universitaet Bochum) 

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MATH+ Grand Opening 

The decision of the German Research Foundation to support the MATH+ Cluster of Excellence gave reason to the Grand Opening. On 14 May 2019, 800 invited guests met in the Berlin Kosmos and spent entertaining moments together and celebrating the great success that is an outstanding achievement for the city of Berlin and for science in Berlin. Among the guests were many renowned scientists and numerous politicians such as State Secretary Steffen Krach.

Sea Ice Antarctica cruise mixed finite elements
Mafelap, 18 - 21 June 2019

Minisymposium on Adaptive and property preserving finite element methods, jointly organised with Pavel Bochev (Sandia National Laboratories, USA) and Jörg Schröder (UDE, Germany) 

Sea Ice Antarctica cruise mixed finite elements
Cyprus, May 17-18, 2019
17th European Finite Element Fair

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Valencia, May 6-10, 2019
Interpore 2019

I presented the new a posteriori error estimates for the three-field variational formulation of the Biot problem involving the displacements, the total pressure and the fluid pressure of this paper with my Co-author Gerhard Starke.
The discretization under focus is the conforming Taylor–Hood finite element combination, consisting of polynomial degrees for the displacements and the fluid pressure and for the total pressure. The symmetry of the reconstructed stress is allowed to be satisfied only weakly. The reconstructions can be performed locally on a set of vertex patches and lead to a guaranteed upper bound for the error with a constant that depends only on local constants associated with the patches and thus on the shape regularity of the triangulation. Particular emphasis is given to nearly incompressible materials and the error estimates hold uniformly in the incompressible limit. Numerical results on the L-shaped domain confirm the theory and the suitable use of the error estimator in adaptive strategies.

Sea Ice Antarctica cruise mixed finite elements
Berlin, April 15-16, 2019

We are so glad to welcome as speaker

S. Sauter (Universität Zürich)
J. Gedicke (Universität Wien)
D. Peterseim (Universität Augsburg)
T. Vejchodsky (Czech Academy of Sciences)
M. Vohralik (Inria research centre Paris)
J. Storn (Humboldt-Universität zu Berlin)
R. Ma (Humboldt-Universität zu Berlin)
D. Boffi (Università di Pavia)
F. Bertrand (Humboldt-Universität zu Berlin)

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Vienna February 18-22, 2019
Gamm Jahrestagung

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January 18-19, 2019
18th-GAMM-Seminar on Microstructures


boffi bertrand mixed finite elements
October 2018: Celebrating 75th years of Mathematics of Computation

With my Co-author Prof. Daniele Boffi we presented our work on a posteriori error estimates for the mixed numerical approximation of the Laplace eigenvalue problem using a reconstruction in the standard conforming space for the primal variable of the mixed Laplace eigenvalue problem. This work compare it with analogous approaches present in the literature for the corresponding source problem. In the case of Raviart–Thomas finite elements of arbitrary polynomial degree, the resulting error estimator constitutes a guaranteed upper bound for the error and is shown to be local efficient. Our reconstruction is performed locally on a set of vertex patches.

Sea Ice Antarctica cruise mixed finite elements
Post-Doc Award of the mathematical faculty in Essen

I received the Post-Doc Award of the mathematical faculty of Essen for my work on parametric finite elements for the mixed approximation of PDEs on domains with curved boundaries.

Sea Ice Antarctica cruise mixed finite elements
Summer 2017, Antarctica cruise


Fleurianne Bertrand
TU Chemnitz
Fakultät für Mathematik
Reichenhainer Straße 41
09126 Chemnitz