Dear colleagues,
We are happy to announce the following online talk:
Speaker: Mario Maurelli(Università di Pisa).
Title: A McKean-Vlasov SDE and particle system with interaction from reflecting boundaries.
Abstract: We consider a one-dimensional McKean-Vlasov SDE on a domain and the associated meanfield interacting particle system. The peculiarity of this system is the combination of the interaction, which keeps the average position prescribed, and the reflection at the boundaries; these two factors make the effect of reflection non local. We show path-wise well-posedness for the McKean-Vlasov SDE and convergence for the particle system in the limit of large particle number. Joint work with Michele Coghi, Wolfgang Dreyer, Peter K. Friz, Paul Gajewski, Clemens Guhlke.
Date and time: Tuesday December 13, 17:30-18:30 (Rome time zone)
Link:
Entra nella riunione in Zoom
https://polimi-it.zoom.us/j/92900386273?pwd=dG1xTUtsN0JpaFl2TWlzRTJ1a0lBZz09
ID riunione: 929 0038 6273
Passcode: 638099
This talk is part of the
(PMS)^2: Pavia-Milano Seminar series on Probability and Mathematical Statistics
organized jointly by the universities Milano-Bicocca, Pavia, Milano-Politecnico.
Participation is free and welcome!
Best regards
The organizers (Carlo Orrieri, Maurizia Rossi, Margherita Zanella)
Buongiorno,
con piacere segnalo il seguente seminario:
--------------------------------
14 dicembre ore 16.00
- aula 203, campus Perrone, via Perrone, 18, Novara. Università del
Piemonte Orientale.
- on-line: meet.google.com/yvq-ccbt-pzt
Dott. Roberto Ascari
Università di Milano-Bicocca
Title: The flexible Latent Dirichlet Allocation
Abstract: Over recent years, text modeling techniques have been employed
in several applications, including the detection of latent topics in text
documents. A widespread statistical tool for topic modeling is the Latent
Dirichlet Allocation (LDA), which allows for a document representation in
terms of topic composition. A well-known limitation of the LDA is related
to the stiffness of the Dirichlet prior imposed on the topic distributions.
To consider a richer dependence structure, we propose a generalization of
the Dirichlet distribution as an alternative distribution, namely the
flexible Dirichlet (FD). The FD is a distribution defined on the simplex
space allowing for a finite mixture structure. This choice introduces
additional parameters in the LDA, and ensures more flexibility, still
maintaining the model interpretability, as well as conjugacy to the
multinomial model. The latter property allows for a Collapsed Gibbs
Sampling-based estimation procedure. The generalization of the LDA based on
the FD distribution is illustrated via an application to a real dataset.
-----------------------------------
Tutti gli interessati sono invitati a partecipare.
Cordiali saluti,
Enea
--
Enea Bongiorno,PhD
Associate Professor of Statistics
Università degli Studi del Piemonte Orientale
Via Perrone 18, 28100, Novara, Italia
Phone: +390321375317
enea.bongiorno(a)uniupo.it
upobook.uniupo.it/enea.bongiorno
Dear Colleagues,
We would like to invite you to the following SPASS
<https://sites.google.com/unipi.it/spass> seminar, jointly organized by
UniPi, SNS, UniFi and UniSi:
*On the infinite dimension limit of invariant measures and solutions of
Zeitlin's 2D Euler equations*
by Milo Viviani (Centro de Giorgi, Scuola Normale Superiore di Pisa)
The seminar will take place in person on *TUE, 13.12.2022 at 14:00 CET* in
Aula Seminari, Department of Mathematics, University of Pisa and streamed
online here <https://meet.google.com/gji-phwo-vbg>.
The organizers,
A. Agazzi, G. Bet, A. Caraceni, F. Grotto, G. Zanco
https://sites.google.com/unipi.it/spass
--------------------------------------------
*Title: **On the infinite dimension limit of invariant measures and
solutions of Zeitlin's 2D Euler equations*
*Abstract: **In this talk we consider a finite dimensional approximation
for the 2D Euler equations on the sphere, proposed by V. Zeitlin, and show
their convergence towards a solution of the Euler equations with marginals
distributed as the enstrophy measure. The method relies on nontrivial
computations on the structure constants of the Poisson algebra of functions
on S², that appear to be new. Finally, we discuss the problem of extending
our results to Gibbsian measures associated with higher Casimirs, via
Zeitlin’s model.*
We are glad to announce the following hybrid seminar:
Monday, 12 of December 2022 at 12:00
In person: Room 3-E4-SR03, floor 3, Bocconi University, Via Roentgen 1,
Milan
Zoom link: https://unibocconi-it.zoom.us/j/95882011831; Meeting ID: 958
8201 1831
Speaker: Stefan Wager (Stanford University)
Title: Learning from a Biased Sample
Abstract: The empirical risk minimization approach to data-driven decision
making assumes that we can learn a decision rule from training data drawn
under the same conditions as the ones we want to deploy it under. However,
in a number of settings, we may be concerned that our training sample is
biased, and that some groups (characterized by either observable or
unobservable attributes) may be under- or over-represented relative to the
general population; and in this setting empirical risk minimization over
the training set may fail to yield rules that perform well at deployment.
Building on concepts from distributionally robust optimization and
sensitivity analysis, we propose a method for learning a decision rule that
minimizes the worst-case risk incurred under a family of test distributions
whose conditional distributions of outcomes Y given covariates X differ
from the conditional training distribution by at most a constant factor,
and whose covariate distributions are absolutely continuous with respect to
the covariate distribution of the training data. We apply a result of
Rockafellar and Uryasev to show that this problem is equivalent to an
augmented convex risk minimization problem. We give statistical guarantees
for learning a robust model using the method of sieves and propose a deep
learning algorithm whose loss function captures our robustness target. We
empirically validate our proposed method in simulations and a case study
with the MIMIC-III dataset.
Best regards,
Giacomo Zanella
Cari colleghi,
nell’ambito del programma di Visiting Professors della Laurea Magistrale in Stochastics and Data Science dell’Università di Torino (il programma completo è consultabile alla pagina https://www.master-sds.unito.it/go/visiting), con piacere annunciamo il seguente corso:
--------------------------------------
MARTA CATALANO (University of Warwick)
DEPENDENT NONPARAMETRIC PRIORS VIA COMPLETELY RANDOM MEASURES
Bayesian nonparametrics provides a natural framework for performing flexible inference with principled quantification of uncertainty. The main ingredients are discrete random measures, whose laws act as prior distribution for infinite-dimensional parameters and, combined with the data, provide their posterior distribution. Recent works use dependent random measures to perform simultaneous inference across multiple samples. The borrowing of strength across different samples is regulated by the dependence structure of the random measures, with complete dependence corresponding to maximal sharing of information and fully exchangeable observations.
In these lectures we start from the notion of completely random measure and describe several ways of introducing dependence between them. Different models may still induce the same amount of borrowing of information, measured by an index of dependence. In the two sample case, this is often achieved by second order summaries of the joint distribution through linear correlation. In the multivariate scenario, we characterise dependence in terms of distance from exchangeability by relying on optimal transport. This allows for informed prior elicitations and provides a fair ground for model comparison.
--------------------------------------
Il corso si svolgerà solo in presenza secondo il seguente calendario
Lez 1: mar 13/12: 14-16 - Aula 4
Lez 2: mer 14/12: 9.15-11.15 - Aula 4
Lez 3: mer 14/12: 14-16 - Aula 30
Lez 4: gio 15/12: 14-16 - Aula 11
Sede dei corsi: Corso Unione Sovietica 218/bis, 10134, Torino
Il corso è rivolto agli studenti della Laurea Magistrale ma la partecipazione è aperta a tutti gli interessati.
Cordiali saluti,
Matteo Ruggiero
---
Matteo Ruggiero
University of Torino and Collegio Carlo Alberto
www.matteoruggiero.it
Buongiorno,
segnaliamo, con preghiera di diffusione, l'opportunità di partecipare al
workshop "*Families in times of accelerated societal and demographic
changes*" dall'11 al 14 gennaio 2023.
Il workshop si terrà nel complesso dell'antico monastero Terme San Marco a
Monteortone, Abano Terme (Pd, Italy).
News:
https://www.unipd.it/news/families-times-accelerated-societal-and-demograph…
********
Organised jointly by the University of Lausanne and Padova, the workshop
“Families in times of accelerated societal and demographic changes” will
take place on January 11-14 2023 in Monteortone, Abano Terme (Italy).
This workshop aims to allow early career scholars and senior researchers to
discuss in both formal and informal ways cutting-edge papers, suggesting
new hypothesis, specific case studies and comparative studies around the
themes of family changes in challenging times.
*CALLS FOR PARTICIPATION:*
Open to:
• Up to 28 PhD students, postdocs and early career scholars
• coming from either European and not European University
• having an interest in family studies
• willing to present a paper in this field
• the call is open to researchers with different backgrounds: e.g.
Sociologists, Demographers, Psychologists, Statisticians, Economists…
• a good command of English as a working language is also required.
The
Berlin-Oxford International Research Training Group (IRTG) 2544
“Stochastic Analysis in Interaction”
offers 8 PhD positions (75% TVL E 13, about 1900 EUR p.m. after taxes,
social security...) for 3 years starting
April 1st, 2023, or soon thereafter.
Funded by the Deutsche Forschungsgemeinschaft (DFG), the IRTG is a joint
research initiative of the stochastic analysis group of FU, HU, TU and
WIAS Berlin with its counterpart at the University of Oxford. The
advertised positions will be based in Berlin and will offer ample
opportunities to interact also with members of the Oxford team, most
notably in a 6-months exchange.
Embedded in a truly international environment, the IRTG students will get
excellent research training in a structured programme focussing on
challenges at the mathematical foundations of Stochastic Analysis as well
as on challenges arising from its various applications, e.g., in physics,
biology, finance or data science. The combined expertise from the Berlin
and Oxford groups will provide a significant breadth in depth and fertile
ground for our students' ambitious research ideas.
Successful candidates will have an MSc degree (or equivalent) in
Mathematics (or a closely related field), strong knowledge of stochastic
analysis, and feel eager to engage in the exchange of ideas with the teams
in both Berlin and Oxford.
Deadline for applications is
December 9, 2022.
Please see
https://stellenticket.de/157323/TUB/?lang=en
for the official job ad and for instructions on how to apply.
Our IRTG webpage
www.math.tu-berlin.de/irtg
offers more information on the Berlin-Oxford IRTG 2544.