The seminar takes place on Fridays, at 14:15 in SR 2.040.
Mailing List
In order to receive e-mails about the Group seminar, please subscribe to the mailing list or send a short e-mail to sanchez(at)iam.uni-bonn(dot)de (Daniel Sánchez-Simón del Pino)
Upcoming
July 3rd at 14:15 in SR 2.040 .
Speaker: Dr. Alessandro Felisi
Title: Stability transition for the inverse transport problem in the diffusive regime
The inverse transport problem consists in retrieving the optical parameters of a medium, namely the absorption and the scattering coefficients, from measurements performed at the domain’s boundary. In this talk, I will show how the relative magnitude of absorption and scattering influences the stability properties of the inverse problem. In particular, I will explain how the severe ill-posedness encountered in the highly-scattering, low-absorption regime is strictly connected to the diffusion approximation in radiative transfer. This is joint work with E. Demattè, A. Rüland and J.J.L. Velázquez.
Schedule
April 17
No Seminar
April 24
Sebastián Flores Sepúlveda
May 1
No seminar
May 8
Simon Ruhland
May 15
TBA
May 22
Lorena Pohl
May 29
No Seminar
June 5
No seminar
June 12
Dr. Eugenia Franco
June 19
Dawoon Jeong
June 26
No Seminar
July 3
Dr. Alessandro Felisi
July 10
Jilly Kevo
July 17
Dr. Katharina Hopf (Weierstrass Institute in Berlin)
July 24
TBA
July 31
TBA
Past talks
April 24th at 14:15 in SR 2.040 .
Speaker: Sebastián Flores Sepúlveda
Title: On the shape of the positivity region for a free boundary problem describing cell polarization
Given a smooth bounded domain in three dimensional space, we study a mass-constrained obstacle-type problem posed on its boundary. This problem has been proposed as a model for cell polarization by Matthias Röger, Barbara Niethammer and Juan J. L. Velázquez in 2020. We describe in detail the shape of the positivity set in the generic case where the signal is a Morse function on the surface. As a consequence, we derive regularity of the free boundary for small positive mass. We also obtain scaling limits in more general settings, and we illustrate behavior where the signal is non-generic by way of some examples.
This is joint work with Barbara Niethammer and Juan J. L. Velázquez
May 8th at 14:15 in SR 2.040 .
Speaker: Simon Ruhland
Title: Resonant solutions to an Euler-Poisson equation
We study the shape of a liquid in two dimensions circling around the common center of mass with some external particle. First, we consider the non-resonant case as proposed in an article by Diego Alonso-Orán, Bernhard Kepka and Juan J. L. Velázquez in 2024. Then we will see what differs in the case of resonance.
May 22nd at 14:15 in SR 2.040 .
Speaker: Lorena Pohl
Title: Long-time behaviour of a nonlocal model for electroporation
We analyze a model for electroporation, a biological process in which a cell membrane exposed to an external voltage becomes permeable due to the formation and growth of nanoscale membrane pores. We prove a local stability result for asymptotic self-similar solutions with a power-law tail. In particular, we show that the transport term drives the long-time behaviour. Joint work with Barbara Niethammer and Juan Velázquez.
June 12th at 14:15 in SR 2.040 .
Speaker: Dr. Eugenia Franco
Title: A multicomponent coagulation equation modeling the coagulation of rouleaux in blood
In this talk we consider a two-component coagulation equation that can be used to model the coagulation of rouleaux in blood. We will characterize the initial data that lead to gelation, i.e. loss of mass conservation in finite time. We will see that, when gelation occurs, the solution to the two-component coagulation equation localizes along a direction of the space of clusters as t approaches the gelation time. We will also see that the solution to the two-component coagulation equation converges to a self-similar solution along the direction of localization. This is joint work with Bernhard Kepka.
June 19th at 14:15 in SR 2.040 .
Speaker: Dawoon Jeong
Title: Boundary Regularity of Rotating Vortex Patches
I will present Burbea's approach to rotating vortex patches (V-states), the bifurcation from the circular vortex patch leading to m-fold symmetric V-states, and the boundary regularity result showing that V-states close to the circle have smooth boundaries.
