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Dienstag, 19.01.2021, 15:15 Uhr (Online Event)
Oberseminar Nonlinear Dynamics
Dr. Michal Hadrava, Institute of Computer Science of the Czech Academy of Sciences, Prague, Czech Republic:
A dynamical systems approach to spectral music: Modeling the role of roughness and inharmonicity in perception of musical tension
mehr ... Veranstaltungsort
Online Event

Abstrakt
Tension-resolution patterns seem to play a dominant role in shaping our emotional experience of music. Whereas in traditional Western music, these patterns are mainly expressed through harmony and melody, many contemporary musical compositions (e.g. so-called ?spectral music") employ sound materials lacking any perceivable pitch structure, rendering these two compositional devices useless. Motivated by recent advances in music-theoretical and neuroscientific research into the related phenomenon of dissonance, we propose a neurodynamical model of musical tension based on a spectral representation of sound and hence applicable to any kind of sound material, pitched or non-pitched.

Weitere Informationen
Diesen Vortrag können Sie mit Zoom verfolgen unter: https://zoom.us/j/82815629022.

Veranstalter
Freie Universität Berlin
WIAS Berlin
Dienstag, 19.01.2021, 16:00 Uhr (Online Event)
Seminar Modern Methods in Applied Stochastics and Nonparametric Statistics
Dr. Dmitrii M. Ostrovskii, University of Southern California:
Near-optimal model discrimination with non-disclosure (online talk)
mehr ... Veranstaltungsort
Online Event

Weitere Informationen
Dieser Vortrag findet bei Zoom statt: https://zoom.us/j/492088715

Veranstalter
WIAS Berlin
Mittwoch, 20.01.2021, 10:00 Uhr (Online Event)
Forschungsseminar Mathematische Statistik
Sven Wang, University of Cambridge:
On polynomial-time computation of high-dimensional posterior measures by Langevin-type algorithms
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Online Event

Abstrakt
In this talk, we consider the task of generating random samples of high-dimensional posterior distributions. The main results consist of non-asymptotic computational guarantees for Langevin-type MCMC algorithms which scale polynomially in key quantities such as the dimension of the model, the desired precision level, and the number of statistical measurements. We also show that posterior mean vectors and maximum a posteriori (MAP) estimates are computable in polynomial time, with high probability under the distribution of the data. Those results are derived in a general non-linear regression setting where posterior measures are not necessarily log-concave. The main example is a non-linear PDE model involving the steady-state Schrödinger equation. The talk is based on the preprint https://arxiv.org/abs/2009.05298.

Weitere Informationen
Der Vortrag findet bei Zoom statt: https://zoom.us/j/159082384

Veranstalter
Humboldt-Universität zu Berlin
WIAS Berlin
Mittwoch, 20.01.2021, 11:30 Uhr (Online Event)
Seminar Interacting Random Systems
Lorenzo Taggi, University of Rome “La Sapienza”, Italien:
Exponential decay of correlations for O(N) spin systems
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Online Event

Abstrakt
The Spin O(N) model is a classical statistical mechanics model whose configurations are collections of unit vectors, called spins, taking values on the surface of a N ?1 dimensional unit sphere, with each spin associated to the vertex of a graph. Some special cases of the spin O(N) model are the Ising model (N = 1), the XY model (N = 2), and the classical Heisenberg model (N = 3). Despite the fact that it is a very classical model, there remain important gaps in understanding, particularly in the case N > 2. This talk will provide an introduction on this class of models and present a new recent result about exponential decay of correlations for arbitrary (non-zero) values of the external magnetic field and arbitrary spin dimension N>1. The proof of this result employs a representation of the model as a system of coloured random paths and a sampling procedure, which allows us to bound from above the "typical lenght" of the open paths. The talk is based on a joint work with B. Lees.

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Seminar Interacting Random Systems

Veranstalter
WIAS Berlin
Donnerstag, 21.01.2021, 15:00 Uhr (Online Event)
TES-Seminar on Energy-based Mathematical Methods and Thermodynamics
Dr. Pierre-Étienne Druet, Technische Universität Berlin WIAS Berlin:
The free energy of incompressible fluid mixtures: An asymptotic study (online talk)
mehr ... Veranstaltungsort
Online Event

Abstrakt
The results presented in this talk are triggered by the modelling of multicomponent fluids at low Mach-number. We first perform the asymptotic of small compressibility for a globally stable phase, and we show that the Helmholtz free energy, which is the crucial constitutive quantity, tends to a limit in the sense of epi- or Gamma-convergence. The essential findings are: The limit model does not only prohibit thermal expansion - this is the well-known Mueller-paradox -, but it also excludes the phenomena of volume loss or excess due to mixing. In order to temper the latter unrealistic conclusion, we modify the basic scenario by performing the limit only inside of a bounded, stable phase. In this way we recover incompressible systems that are not volume additive. Moreover, the limit free energy depends continuously on the state variables. This research is joined work with D.Bothe (TU Darmstadt) and W.Dreyer (WIAS Berlin).

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TES-Seminar on Energy-based Mathematical Methods and Thermodynamics (online talk)

Veranstalter
Technische Universität Berlin
WIAS Berlin