Subject: Vorträge Fornasier, Ward, 11.2.
From: Holger Rauhut <[email-masked]>
To: Martin Rumpf <[email-masked]>, Michael Griebel <[email-masked]>, Alexey Chernov <[email-masked]>, [email-masked], [email-masked], [email-masked], [email-masked]
Date: Fri, 6 Feb 2009 09:04:27 +0100

Liebe Kollegen,

ich würde gerne auf 2 Vorträge meiner Gäste
am nächsten Mittwoch (11.2.) aufmerksam machen:

14:00 Uhr Rachel Ward (Princeton University): Cross Validation in  
Compressed Sensing
Abstract: The emerging area of Compressed Sensing revolves around the  
surprising fact that underdetermined linear systems of the form Ax = y  
can be efficiently solved if x is known a priori to be sufficiently  
sparse, that is, to have sufficiently small support. Most real world  
signals x are not exactly sparse, but rather approximately sparse, in  
which case only an approximation to the underlying signal x satisfying  
Ax = y can be found in general. In this talk, we will show how cross  
validation-type techniques used in statistics and learning theory  
naturally apply in the Compressed Sensing setup and offer very  
efficient tight bounds on the root mean squared error ||x - x*||  
between the approximation x* and underlying signal x. Cross Validation  
techniques can be used for parameter selection in Compressed Sensing  
as well.

15.15 Uhr
Massimo Fornasier (RICAM, Linz): Kinetic models for flocking
Abstract: In this talk we introduce and analyze a continuous version  
of the flocking model of Cucker and Smale, which describes the state  
of a population of birds. Within the same idea that a bird adjusts its  
velocity towards the average of neighbors' velocities, we construct a  
spatially dependent Boltzmann-type equation which describes the  
behavior of the flock in terms of a density $f =f(x,v,t)$. The large- 
time behavior of $f$ is subsequently studied by means of mass  
transportation techniques. A continuous analogue of the theorems of  
Cucker and Smale which ensures convergence to a "compact flock" is  
shown to hold for the solution. Several modifications are also  
presented as well as numerical examples. The results presented in this  
talk are a joint work with Giuseppe Toscani e Jose' Carrillo.

Beide Vorträge finden im Konferenz-Raum der Villa Maria, Endenicher  
Allee 62, statt.

Ich würde mich über Euer Erscheinen bzw. über Weitergabe dieser  
Information freuen.

Viele Grüße,
Holger