Return-Path: Received: from murder ([unix socket]) (authenticated user=griebel.ins.uni-bonn.de bits=0) by merkur (Cyrus v2.2.13-Debian-2.2.13-10) with LMTPA; Fri, 06 Feb 2009 09:04:39 +0100 X-Sieve: CMU Sieve 2.2 X-Spam-Checker-Version: SpamAssassin 3.2.3-schwind1 (2007-08-08) on merkur.ins.uni-bonn.de X-Spam-Level: X-Spam-Status: No, score=-0.3 required=5.0 tests=AWL,BAYES_50,HTML_MESSAGE autolearn=no version=3.2.3-schwind1 Received: from uni-bonn.de (mail.uni-bonn.de [131.220.15.113]) by merkur.ins.uni-bonn.de (Postfix) with ESMTP id 02B29400031CB; Fri, 6 Feb 2009 09:04:28 +0100 (CET) Received: from [131.220.174.123] ([131.220.174.123] verified) by fe2.uni-bonn.de (CommuniGate Pro SMTP 5.0.14) with ESMTP id 11337418; Fri, 06 Feb 2009 09:04:27 +0100 Message-Id: <0D779950-85C4-42EA-85E0-32F09E7A5CE4@hcm.uni-bonn.de> From: Holger Rauhut To: Martin Rumpf , Michael Griebel , Alexey Chernov , bebendorf@ins.uni-bonn.de, harbrecht@ins.uni-bonn.de, cristian.sminchisescu@ins.uni-bonn.de, bartels@ins.uni-bonn.de Content-Type: multipart/alternative; boundary=Apple-Mail-4-49713506 Mime-Version: 1.0 (Apple Message framework v928.1) Subject: =?ISO-8859-1?Q?Vortr=E4ge_Fornasier,_Ward,_11.2.?= Date: Fri, 6 Feb 2009 09:04:27 +0100 X-Mailer: Apple Mail (2.928.1) X-Virus-Status: No X-Virus-Checker-Version: clamassassin 1.2.3 with clamdscan / ClamAV 0.94.2/8959/Fri Feb 6 06:58:05 2009 --Apple-Mail-4-49713506 Content-Type: text/plain; charset=ISO-8859-1; format=flowed; delsp=yes Content-Transfer-Encoding: quoted-printable Liebe Kollegen, ich w=FCrde gerne auf 2 Vortr=E4ge meiner G=E4ste am n=E4chsten Mittwoch (11.2.) aufmerksam machen: 14:00 Uhr Rachel Ward (Princeton University): Cross Validation in =20 Compressed Sensing Abstract: The emerging area of Compressed Sensing revolves around the =20= surprising fact that underdetermined linear systems of the form Ax =3D y = =20 can be efficiently solved if x is known a priori to be sufficiently =20 sparse, that is, to have sufficiently small support. Most real world =20 signals x are not exactly sparse, but rather approximately sparse, in =20= which case only an approximation to the underlying signal x satisfying =20= Ax =3D y can be found in general. In this talk, we will show how cross =20= validation-type techniques used in statistics and learning theory =20 naturally apply in the Compressed Sensing setup and offer very =20 efficient tight bounds on the root mean squared error ||x - x*|| =20 between the approximation x* and underlying signal x. Cross Validation =20= techniques can be used for parameter selection in Compressed Sensing =20 as well. 15.15 Uhr Massimo Fornasier (RICAM, Linz): Kinetic models for flocking Abstract: In this talk we introduce and analyze a continuous version =20 of the flocking model of Cucker and Smale, which describes the state =20 of a population of birds. Within the same idea that a bird adjusts its =20= velocity towards the average of neighbors' velocities, we construct a =20= spatially dependent Boltzmann-type equation which describes the =20 behavior of the flock in terms of a density $f =3Df(x,v,t)$. The large-=20= time behavior of $f$ is subsequently studied by means of mass =20 transportation techniques. A continuous analogue of the theorems of =20 Cucker and Smale which ensures convergence to a "compact flock" is =20 shown to hold for the solution. Several modifications are also =20 presented as well as numerical examples. The results presented in this =20= talk are a joint work with Giuseppe Toscani e Jose' Carrillo. Beide Vortr=E4ge finden im Konferenz-Raum der Villa Maria, Endenicher =20= Allee 62, statt. Ich w=FCrde mich =FCber Euer Erscheinen bzw. =FCber Weitergabe dieser =20= Information freuen. Viele Gr=FC=DFe, Holger --Apple-Mail-4-49713506 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Liebe = Kollegen,

ich w=FCrde gerne auf 2 Vortr=E4ge meiner = G=E4ste 
am n=E4chsten 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 =3D= 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 =3D 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 $f =3Df(x,v,t)$. 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 Vortr=E4ge = finden im Konferenz-Raum der Villa Maria, Endenicher Allee 62, = statt.

Ich w=FCrde mich =FCber Euer Erscheinen = bzw. =FCber Weitergabe dieser Information = freuen.

Viele = Gr=FC=DFe,
Holger