Synergies

Mutual seminars
NOV 8 2019
University of Stirling, Division of Computing Science and Mathematics
Multi-exponential analysis might sound remote, but it touches our lives in many surprising ways, even if most people are unaware of just how important it is. For example, a substantial amount of effort in the field of signal processing is essentially dedicated to the analysis of multi-exponential functions whose exponents are complex. The analysis of exponential functions whose exponents are very near each other is directly linked to superresolution imaging. Read More
JAN 16 2019
National Taiwan Normal University, Taipei, Taiwan
SEP 28 2018
University of Stirling, Division of Computing Science and Mathematics
The talk will start with a brief introduction of US NSF's 10 Big Ideas and give an overview of the recent trend of computational mathematics in the US. Then I will present my own research topic which will serve as an example to demonstrate how a problem in composite materials can be studied from the computational mathematics point of view. Read More
SEP 14 2018
University of Stirling, Division of Computing Science and Mathematics
Integer matrices are often characterized by the lattice of combinations of their rows or columns. This is captured nicely by the Smith canonical form, a diagonal matrix of invariant factors, to which any integer matrix can be transformed through left and right multiplication by unimodular matrices. Algorithms for computing Smith forms have seen dramatic improvements over the past 40 years, but effective algorithms for large sparse matrices still need improvement. Read More
JUN 19 2018
Georg-August-Universität Göttingen, Institute for Numerical and Applied Mathematics
We consider the task of updating a matrix function f(A) when the matrix A ∈ Cnxn is subject to a low-rank modification. In other words, we aim at approximating f(A+D)-f(A) for a matrix D of rank k ≪ n. The approach proposed in this talk attains efficiency by projecting onto tensorized Krylov subspaces produced by matrix-vector multiplications with A and A*. Read More
APR 17 2018
Georg-August-Universität Göttingen, Institute for Numerical and Applied Mathematics
Estimating the spectral information of an exponential sum plays an important role in many signal processing applications. In particular, we mention nuclear magnetic resonance (NMR) spectroscopy and the direction of arrival (DOA) problem in smart antenna technology. We present a parametric method that can circumvent the Shannon-Nyquist sampling rate and break the curse of dimensionality. Read More
DEC 21 2017
Universiteit Antwerpen, Department of Mathematics and Computer Science
NOV 17 2017
Universiteit Antwerpen, Department of Mathematics and Computer Science
In signal processing data are traditionally sampled according to the Shannon-Nyquist theorem in order to prevent aliasing effects. Here we focus on parametric methods and introduce a procedure that allows these methods to work with sub-sampled data. We actually make use of the aliasing effect to regularize the problem statement rather than that we avoid it. Read More
MAY 16 2017
Georg-August-Universität Göttingen, Institute for Numerical and Applied Mathematics
Rational functions like for instance Padé approximants play an important role in signal processing, sparse interpolation and exponential analysis. They have good theoretical properties in approximation and modeling. However, for a successful modeling with help of rational functions we want to make sure that there is no ”similar” rational function being degenerate, i.e., having strictly smaller degree of both degrees of numerator and denominator. Read More
MAY 20 2016
Université de Lille
DEC 10 2015
Université des Sciences et Technologies de Lille - Lille I
Reconstructing a digital signal from its measurements is an inverse problem that can be extremely ill-posed. Meanwhile, sampling a signal uniformly below the Shannon-Nyquist rate leads to aliasing, an unwanted effect causing different signals to become indistinguishable. Read More
NOV 23 2015
Universiteit Antwerpen, Department of Mathematics and Computer Science
Rational functions like for instance Padé approximants play an important role in signal processing, sparse interpolation and exponential analysis. However, for a successful modeling with help of rational functions we want to make sure that there is no ”similar” rational function being degenerate, i.e., having strictly smaller degree of both degrees of numerator and denominator. Read More
NOV 12 2015
Universiteit Antwerpen, Department of Mathematics and Computer Science
Padé approximants play an important role in signal processing, sparse interpolation and exponential analysis. In this talk we will report about recent results concerning the forward and backward conditioning of the (real) Padé map, which sends a vector of Taylor coefficients onto the normalized vector of coefficients of the Padé numerator and denominator. Read More
NOV 9 2015
Department of Mathematical Sciences, University of Delaware
OCT 19 2015
Universiteit Antwerpen, Department of Mathematics and Computer Science
We derive a new generalization of Prony's method to reconstruct M-sparse expansions of (generalized) eigenfunctions of linear operators from only O(M) suitable values in a deterministic way. Read More
JAN 20 2015
Georg-August-Universität Göttingen, Institute for Numerical and Applied Mathematics
Tutorials
JUL 25 - AUG 2 2019
5th Algorithmic and Enumerative Combinatorics Summer School 2019, Hagenberg, Austria
Series of five research lectures for graduate students and researchers.
NOV 26 - 29 2018
Research Training Group 2088, Georg-August-Universität Göttingen
SEP 18 2017
Computer Algebra in Scientific Computing (CASC 2017)
A mathematical model is called sparse if it is a combination of only a few non-zero terms. In sparse interpolation, the aim is to determine both the support of the sparse linear combination and the scalar coefficients in the representation, from a small or minimal amount of data samples. Read More
SEP 8 - 12 2014
Dolomites Research Week on Approximation (DRWA14)
Within the last time, various adaptive methods for signal and image approximation have been suggested. Instead of choosing a priori a basis or a frame to approximate an image, one tries to adapt the approximation scheme to the image geometry. Read More
SEP 8 - 12 2014
Dolomites Research Week on Approximation (DRWA14)
Throughout computational science and engineering, several attempts have been made to represent data in a parsimonious way. Mathematical models are proposed in which the major features of the data are represented using only a few terms, in other words, models that use a sparse combination of generating elements instead of a linear combination of all basis elements. Read More
SEP 23 - 25 2013
Summer School on Applied Analysis 2013 (CMS13)
A crucial problem in data analysis is to construct efficient low-level representations of mathematical objects from discrete signal data while preserving characteristic properties of the target object. In recent years, many ideas have been developed to design adaptive approximation schemes for signals and images taking into account some a-priori knowledge about their structure. Read More
Organized events
NOV 26 - 27 2018
Gerlind Plonka-Hoch
SEP 10 - 14 2018
Gerlind Plonka-Hoch
et al.
MAY 31 - JUN 1 2018
Ana C. Matos
Bernhard Beckermann
et al.
JUL 31 - AUG 4 2017
Wen-shin Lee
et al.
OCT 30 - NOV 4 2016
Annie Cuyt
et al.
JUL  16 - 18 2016
Wen-shin Lee
Mark Giesbrecht
et al.
MAY 20 2016
5èmes Journées Approximation, International conference on constructive complex approximation
Université des Sciences et Technologies de Lille - Lille I, France
Ana C. Matos
Bernhard Beckermann
et al.
JUN 14 - 19 2015
Annie Cuyt
et al.
Research visits

February 17-25, 2020

Visit of Wen-shin Lee (University of Stirling) to Universiteit Antwerpen

January 27-31, 2020

Annie Cuyt (Universiteit Antwerpen) to University of Stirling

January 4-12, 2020

Visit of George Labahn (University of Waterloo) to Université de Lille

November 3-8, 2019

Annie Cuyt (Universiteit Antwerpen) to University of Stirling

September 30 - October 4, 2019

Visit of Wen-shin Lee (University of Stirling) to Universiteit Antwerpen

September 5, 2019

Visit of Dirk de Villiers (Stellenbosch University, South Africa) to Universiteit Antwerpen

September 1-5, 2019

Visit of Rina-Mari Weideman (Stellenbosch University, South Africa) to Universiteit Antwerpen

March 23 - April 2, 2019

Visit of George Labahn (University of Waterloo) to Université de Lille

March 22-27, 2019

Visit of Wen-shin Lee (University of Stirling) to Universiteit Antwerpen

November 26-30, 2018

Visit of Annie Cuyt (Universiteit Antwerpen, Belgium) to Georg-August-Universität Göttingen.

October 18-26, 2018

Visit of Wen-shin Lee (University of Stirling) to Universiteit Antwerpen

September 24-28, 2018

Visit of Yvonne Ou (University of Delaware) to University of Stirling

September 10-14, 2018

Visit of Mark Giesbrecht (University of Waterloo) to University of Stirling

May 1-3, 2018

Visit of Dirk de Villiers (Stellenbosch University, South Africa) to ASTRON

April 30, 2018

Visit of Dirk de Villiers (Stellenbosch University, South Africa) to Universiteit Antwerpen.

December 21-22, 2017

Visit of Gerlind Plonka-Hoch (Georg-August-Universität Göttingen, Germany) to Universiteit Antwerpen.

September 19, 2016 - February 17, 2017

Several visits of Ridalise Louw (Stellenbosch University, South-Africa) to Universiteit Antwerpen.

May 15-17, 2017

Visit of Ana Matos (Université des Sciences et Technologies de Lille - Lille I, France) to Georg-August-Universität Göttingen.

January 21-28, 2017

Visit of George Labahn (University of Waterloo) to Université de Lille

September 19, 2016 - February 17, 2017

Visit of Ridalise Louw (Stellenbosch University, South Africa) (Erasmus Mundus) to Universiteit Antwerpen.

April 15-20, 2016

Visit of George Labahn (University of Waterloo) to Université de Lille

November 11-12, 2015

Visit of Bernhard Beckermann and Ana C. Matos (Université des Sciences et Technologies de Lille - Lille I, France) to Universiteit Antwerpen.

October 19-21, 2015

Visit of Gerlind Plonka-Hoch (Georg-August-Universität Göttingen, Germany) to Universiteit Antwerpen.