I³MS - Klawonn Seminar

Location: AICES Seminar Room 115, 1st floor, Schinkelstr. 2, 52062 Aachen

Prof. Dr. Axel Klawonn - Towards Computing on the Extreme Scale in Nonlinear Solid Mechanics

Chair of Numerical Mathematics and Scientific Computing, University of Cologne




Location: SUPERC, 6th Floor, Generali Room, 52062 Aachen

Prof. Dr.-Ing. Wolfgang Marquardt - Energiewende - Opportunities for Systems Modelling and Optimization

Chairman of the Board of Directors Forschungszentrum Jülich GmbHForschungszentrum Jülich GmbH


The transformation of the energy system poses not only political and socio-economic but also technical challenges. The envisioned completereplacement of nuclear and fossil energies by renewable energies is not possible with existing technological solutions. Novel concepts and technology options for decarbonisation, decentralization and digitalization
are required. Breakthroughs can only be expected if research and development broadly addresses the specific needs of a future energy system which is fully based on renewable sources. Given the complexity of the problem as well as the ambitious timeline announced by policy makers requires accelerated research processes which provide transformative knowledge and systemic solutions, which are "first time right".  Systems modeling and numerical optimization are key enablers in this respect. The lecture will introduce the ambitious goals of the Energiewende in Germany and the
resulting technological key challenges. The stabilization of the grid by appropriate design as well as reactive and proactive operational strategies will be exemplarily used to motivate the need for advanced optimization-based computational techniques and to illustrate their potential.

I³MS - Tempone Seminar

Location: AICES Seminar Room 115, 1st floor, Schinkelstr. 2, 52062 Aachen

Prof. Dr. Raul F. Tempone - A Potpourri of Results from the KAUST Uncertainty Quantification Center

King Abdullah University of Science and Technology, Kingdom of Saudi Arabia


In this talk, we will present several results produced at the KAUST Strategic Research Initiative for Uncertainty Quantification.

These include, among others, contributions on Multi-level and Multi-index sampling techniques that address both direct and

inverse problems. We may also discuss efficient methods for Bayesian Inverse Problems and Optimal Experimental Design.

EU Regional School - Crane Seminar

Location: AICES Seminar Room 115, 1st floor, Schinkelstr. 2, 52062 Aachen

Prof. Dr. Keenan Crane - Conformal Geometry Processing

Computer Science Department, Robotics Institute 
Carnegie Mellon University, USA


Digital geometry processing is the natural extension of traditional signal processing to three-dimensional geometric data. In recent years, methods based on so-called conformal (i.e., angle-preserving) transformations have proven to be a powerful paradigm for geometry processing since (i) numerical problems are typically linear, providing scalability and guarantees of correctness and (ii) conformal descriptions of geometry are often dramatically simpler or lower-dimensional than traditional encodings. This lecture will touch on both the mathematical foundations of conformal geometry, as well as recent numerical techniques and applications in 3D geometry processing. 

I³MS - Rossmanith Seminar

Location: AICES Seminar Room 115, 1st floor, Schinkelstr. 2, 52062 Aachen

Prof. Dr. James Rossmanith - The Regionally-Implicit Discontinuous Galerkin Method: Improving the Stability of High-Order DG-FEM

Department of Mathematics
Iowa State University, USA


Discontinuous Galerkin (DG) methods for hyperbolic partial differential equations (PDEs) with explicit time-stepping schemes such as strong stability-preserving Runge-Kutta (SSP-RK) suffer from time-step restrictions that are significantly worse than what a simple Courant-Friedrichs-Lewy (CFL) argument requires. In particular, the maximum stable time-step scales inversely with the highest degree in the DG polynomial approximation space and becomes progressively smaller with each added spatial dimension. In this work we introduce a novel approach that we have dubbed the regionally implicit discontinuous Galerkin method (RIDG) to overcome these small time-step restrictions. The RIDG is method is based on an extension of the Lax-Wendroff DG (LxW-DG) method, which previously had been shown to be equivalent (for linear constant coefficient problems) to a predictor-corrector approach, where the predictor is a locally implicit space-time method (i.e., the predictor is something like a block-Jacobi update for a fully implicit space-time DG method). The corrector is an explicit method that uses the space-time reconstructed solution from the predictor step. In this work we modify the predictor to include not just local information, but also neighboring information. With this modification we show that the stability is greatly enhanced; in particular, we show that we are able to remove the polynomial degree dependence of the maximum time-step and show vastly improved time-steps in multiple spatial dimensions. A semi-analytic von Neumann analysis is presented and several tests are shown to verify the efficiency of the proposed scheme.

This work is joint with Pierson Guthrey.