International Francqui Chair 2009-2010: Prof. Ingrid Daubechies (Princeton University)
Inaugural lecture: Monday February 1, 2010 at 16h
(Auditorium QD, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel)
Discrete differential geometry and
measuring similarity between surfaces
Two-dimensional surfaces play an
important role in a wide range of fields, from
Toy Story to complex material interfaces and
your brain cortex. To recognize and classify
objects, or to detect changes, it is useful to
quantify how similar two surfaces are, i.e. to
define a "similarity metric" on the set of
two-dimensional surfaces in three-dimensional
space that makes mathematical sense and is easy
to compute. This talk will illustrate work by
Yaron Lipman and the speaker that uses discrete
differential geometry (no---it is not an
oxymoron!) to tackle this question, and will
showcase an application to lemur dentistry.
Download: Poster (A2),
slides (zipped).
If you come by car you need to scan this bar code (pdf) at entrance 6 or 13 of the campus to open the gate (scanner under intercom).
Other lectures:
Mathematics meets Fine Arts: analyzing paintings with image processing tools
March 1st 2010, 16h00.
Universiteit Gent, "Academieraadzaal" (Aula of Ghent University), Voldersstraat 9, 9000 Gent.
Please register
here.
Independent component analysis and functional Magnetic Resonance Imaging
March 15th 2010, 14h00. UCLouvain, Auditoire Science 02.
Link to UCL site of this talk
here (includes a video of this lecture).
Independent Component Analysis (ICA), a method for separating
a mixture of different components into its constituents, has been
proposed for a variety of different applications, including functional
Magnetic Resonance Imaging (fMRI) of brain processes. The presentation
summarizes the findings of several years of interaction between
applied mathematicians and neuroscientists, expert in fMRI, concentrating
on probing ICA methods for brain fMRI. This study raised questions,
informed by mathematical considerations, that are investigated using
numerical simulations and specially designed fMRI experiments.
The intent was not to cast doubt on the successes of ICA methods for fMRI
data analysis, but rather to understand the elements that determine
the methods' success; this led us to a surprising result.
Synchrosqueezed Wavelet Transforms: a Tool for Empirical Mode Decomposition
April 23th 2010, 16h00.
Université Libre de Bruxelles, Campus Plaine, Forum D.
The EMD algorithm, first proposed by Norden Huang, made more robust
as well as more versatile by Huang and Zhaohua Wu, is a technique that
aims to decompose into their building blocks functions that are the
superposition of a (reasonably) small number of components, well
separated in the time-frequency plane, each of which can be viewed as
approximately harmonic locally, with slowly varying amplitudes and
frequencies. This decomposition has shown its usefulness in a wide
range of applications including meteorology, structural
stability analysis and medical studies.
On the other hand, the EMD algorithm contains heuristic and ad-hoc
elements that make it hard to analyze mathematically.
The talk will describe a method that captures the
flavor and philosophy of the EMD approach, albeit using a different
approach in constructing the components. We shall define a precise
mathematical definition for a class of functions that can be viewed
as a superposition of a reasonably small number of approximately
harmonic components, and we prove that the new method does indeed
succeed in decomposing arbitrary functions in this class.
We provide several examples, for simulated as well as real data.
Francqui Foundation:
The
Francqui Foundation's objective is "to further the development of higher education and scientific research in Belgium". Each year, the Francqui Foundation decides on the attribution of "Interuniversitary Foreign Francqui Chairs" to invite a scientist for a six month sabbatical at a Belgian University (in partnership with other universities).
Inviting universities:
The present Francqui consortium consists of
Vrije Universiteit Brussel (host institution),
Université Libre de Bruxelles,
Université Catholique de Louvain and
Universiteit Gent.
Contact:
- Dr. Ignace Loris (VUB)
- Prof. Christine De Mol (ULB)
- Prof. Aleksandra Pizurica (UGent)
- Prof. Benoit Macq (UCLouvain)
