Upcoming Events
- Tuesday, 18.11.2025, 15:00 (WIAS-405-406)
- Seminar Modern Methods in Applied Stochastics and Nonparametric Statistics
Dr. Davit Gogolashvili, WIAS Berlin:
Local regression on path spaces with signature metrics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Raum: 405/406
Abstract
We study nonparametric regression and classification for path-valued data. We introduce a functional Nadaraya-Watson estimator that combines the signature transform from rough path theory with local kernel regression. The signature transform provides a principled way to encode sequential data through iterated integrals, enabling direct comparison of paths in a natural metric space. Our approach leverages signature-induced distances within the classical kernel regression framework, achieving computational efficiency while avoiding the scalability bottlenecks of large-scale kernel matrix operations. We establish finite-sample convergence bounds demonstrating favorable statistical properties of signature-based distances compared to traditional metrics in infinite-dimensional settings. We propose robust signature variants that provide stability against outliers, enhancing practical performance. Applications to both synthetic and real-world data-including stochastic differential equation learning and time series classification-demonstrate competitive accuracy while offering significant computational advantages over existing methods.
Further Informations
Dieser Vortrag findet auch via Zoom statt: https://wias-berlin-de.zoom-x.de/j/69982487566
Host
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
- Wednesday, 19.11.2025, 10:00 (WIAS-ESH)
- Forschungsseminar Mathematische Statistik
Prof. Dr. Alain Celisse, Université Panthéon-Sorbonne, Frankreich:
Early stopping in fixed-design regression with projection estimators
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Further Informations
Dieser Vortrag findet hybrid statt. Die Teilnahme per Zoom ist über den (neuen!) Link:
https://hu-berlin.zoom-x.de/j/64809417303?pwd=iLT5xbdDZspAcUCuLrwNnaN90ZQBpj.1
Meeting-ID: 648 0941 7303
Passwort: 258449
Host
Humboldt-Universität zu Berlin
Universität Potsdam
WIAS Berlin
- Wednesday, 19.11.2025, 14:15 (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Lutz Recke, Humboldt-Universität zu Berlin:
An H-convergence-based implicit function theorem and homogenization of nonlinear non-smooth elliptic systems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- Thursday, 20.11.2025, 14:00 (WIAS-406)
- Seminar Materialmodellierung
Dr. Andrea Giudici, University of Oxford, GB:
From particle stresses to electrolyte flow: How mechanics affects the performance of lithium-ion batteries
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Abstract
Lithium-ion batteries are typically described by electrochemical models, yet mechanical effects play a decisive role in their operation and degradation. During cycling, swelling of active particles generates stresses and deformations that propagate across scales. These mechanical effects couple back into electrochemistry in two distinct ways.First, stresses around active particles modify lithium transport by altering the local chemical potential, leading to shifts in voltage curves that cannot be captured by standard Doyle?Fuller?Newman-type models. Using asymptotic homogenisation, we extend reduced-order models to incorporate this multiscale coupling systematically.Second, electrode swelling changes porosity and drives electrolyte flows. These flows interact with concentration gradients, causing an irreversible redistribution of electrolyte salt?typically bulk accumulation and edge depletion?conditions that promote lithium plating and performance loss. We model the flow-concentration coupling and derive a closed-form expression for the resulting electrolyte-movement-induced salt inhomogeneity (EMSI) in terms of swelling, porosity, permeability, and nonlinear mechanics, providing a mechanistic explanation of this degradation pathway.
Further Informations
Material Modeling Seminar
Host
WIAS Berlin
- November 21, 2025 (WIAS-ESH)
- Workshop/Konferenz: CRC Day on Rough Volatility
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- Monday, 24.11.2025, 11:30 (WIAS-ESH)
- Seminar Interacting Random Systems
François Baccelli, Unité de Recherche de Rocquencourt and ENS (Département d'Informatique, Frankreich:
Dynamical tessellations
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Further Informations
Seminar Interacting random Systems
Host
WIAS Berlin
- Tuesday, 25.11.2025, 14:00 (WIAS-Library)
- Seminar Materialmodellierung
Dr. Ralf Blossey, Université de Lille, Frankreich:
Structural polarization in electrolytes: A continuum approach
more ... Location
Weierstraß-Institut, Hausvogteiplatz 5-7, 10117 Berlin, R411
Abstract
The standard continuum description of electrolytes is given by Poisson--Boltzmann theory. It describes a structureless solvent with a given dielectric constant (typically around 80, for water), and the dissociated ions by Boltzmann factors. Experimental advances in the past decades, and notably the ever-improving use of atomic force microscopy (AFM) in solution, have opened up new challenges for the mathematical description of electrolytes that require going beyond this basic approach, with numerous putative applications in biology and nanoscience, from biological cells to batteries. In this talk I will describe a recently developed theory of structural polarization forces in electrolytes that combines nonlocal and nonlinear interactions in such systems. After formulating the essential ingredients of this approach, I will discuss the derivation of boundary conditions and highlight some exemplary applications that are currently under way. Recent further developments for metal-solvent interfaces will be also be briefly discussed.
References :
R. Blossey and R. Podgornik, Field theory of structured liquid dielectrics, Phys. Rev. Res. 4, 023033 (2022)
R. Blossey and R. Podgornik, A comprehensive continuum theory of structured liquids, J. Phys. A: Math. Theor. 56 025002 (2023)
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
WIAS Berlin
- Wednesday, 26.11.2025, 11:30 (WIAS-406)
- Seminar Interacting Random Systems
Anh Duc Vu, WIAS Berlin:
tba
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, 4. Etage, Weierstraß-Hörsaal (Raum: 406)
Host
WIAS Berlin
- Wednesday, 26.11.2025, 14:15 (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Illia Karabash, Universität Bonn:
Random boundary conditions for open resonators and the Laplace--Beltrami--Weyl asymptotics
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstract
Motivated by engineering and Photonics research on open resonators in structured deterministic or stochastic environments, the talk introduces rigorous randomizations of absorbing and conservative boundary conditions on Lipschitz boundaries. As underlying PDEs, we choose div-grad acoustic systems, which can be also considered as dimensionally reduced Maxwell equations. We give a description of random m-dissipative boundary conditions that produce acoustic operators with almost surely (a.s.) compact resolvents, and so, also with a.s. discrete spectra, which may be interpreted as stochastic point processes. Based on these results, examples of mathematically convenient randomizations are constructed in terms of eigenfunctions of Laplace--Beltrami operators. It will be shown that, for these special randomizations, the resolvent compactness is connected with the Weyl law on the boundary. If time allows us, the asymptotics of the Laplace--Beltrami eigenvalues on non-smooth boundaries will be also discussed. The talk is based on the paper https://doi.org/10.1016/j.jmaa.2025.129985.
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- Wednesday, 17.12.2025, 14:15 (WIAS-ESH)
- Berliner Oberseminar „Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Dr. Sebastian Hensel, Universität Leipzig:
A weak-strong uniqueness principle for the Mullins--Sekerka equation
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Abstract
We establish a weak-strong uniqueness principle for the two-phase Mullins--Sekerka equation in ambient dimension d = 2 and 3: As long as a classical solution to the evolution problem exists, any weak De Giorgi type varifold solution (see for this notion the recent work with Stinson, Arch. Ration. Mech. Anal. 248, 8, 2024) must coincide with it. In particular, in the absence of topology changes such weak solutions do not introduce a mechanism for (unphysical) non-uniqueness. We also derive a stability estimate with respect to changes in the data. I will explain our method which is based on the notion of relative entropies for interface evolution problems, a reduction argument to a perturbative setting, and a stability analysis in this perturbative regime relying crucially on the gradient flow structure of the Mullins--Sekerka equation. This is joint work with Julian Fischer, Tim Laux and Theresa M. Simon.
Further Informations
Oberseminar “Nichtlineare partielle Differentialgleichungen” (Langenbach-Seminar)
Host
Humboldt-Universität zu Berlin
WIAS Berlin
- January 12 – 13, 2026 (WIAS-ESH)
- Workshop/Konferenz: Recent Trends in Coupled Network Systems
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin
- March 2 – 4, 2026 (IHP)
- Workshop/Konferenz: Leibniz MMS Days 2026
more ... Location
Leibniz Institute for High Performance Microelectronics Frankfurt/Oder
Host
Leibniz Institute for High Performance Microelectronics Frankfurt/Oder
WIAS Berlin
- June 1 – 5, 2026 (WIAS-ESH)
- Workshop/Konferenz: ESGI 194 - The Berlin Study Group with Industry
more ... Location
Weierstraß-Institut, Mohrenstr. 39, 10117 Berlin, Erdgeschoss, Erhard-Schmidt-Hörsaal
Host
WIAS Berlin