Random February 2023

random@lists.dm.unipi.it

36 participants
57 discussions

Seminar in Statistics - Giovanni Rabitti & Thomas Berrett
by Pierpaolo De Blasi 24 Feb '23

24 Feb '23

SEMINARS IN STATISTICS @ COLLEGIO CARLO ALBERTO <https://www.carloalberto.org/events/category/seminars/seminars-in-statistic…> Venerdi 3 Marzo 2023, presso il Collegio Carlo Alberto, in Piazza Arbarello 8, Torino, si terranno i seguenti 2 seminari: ------------------------------------------------ Time: 11.00 - 12.00 Speaker: *Giovanni Rabitti* (Heriot Watt University, Edinburgh) Title: *Fantastic sensitivity measures and where to find them* Abstract: Data science and scientific modeling are extensively used to provide predictions for policy-making purposes. However, resulting communications need to be supported by a proper uncertainty quantification to assess variability in model predictions, by the identification of the key-uncertainty drivers. This information can be provided by statisticians with sensitivity analysis methods. Knowing the drivers of uncertainty supports effective policy-making. This talk is a guided tour in sensitivity analysis techniques and some recent results. In the first part of the talk, starting from the basics, local and global methods will be introduced. When the model is large (i.e. with many input variables), screening techniques are typically used to reduce the dimensionality of the scientific model and will be presented in the talk. In the second part of the talk, I will introduce cooperative games techniques to assess variable importance. I will present recent results on the computation on these importance measures, as well as their application to GAM models, to extreme value problems and to two actuarial pricing models. If there is time, I will introduce a game-theoretic interaction index for discovering subjects at higher identification risk. ------------------------------------------------ Time: 12.00 - 13.00 Speaker: *Thomas Berrett* (University of Warwick) Title: *Optimal nonparametric testing of Missing Completely At Random, and its connections to compatibility* Abstract: Given a set of incomplete observations, we study the nonparametric problem of testing whether data are Missing Completely At Random (MCAR). Our first contribution is to characterise precisely the set of alternatives that can be distinguished from the MCAR null hypothesis. This reveals interesting and novel links to the theory of Frechet classes (in particular, compatible distributions) and linear programming, that allow us to propose MCAR tests that are consistent against all detectable alternatives. We define an incompatibility index as a natural measure of ease of detectability, establish its key properties, and show how it can be computed exactly in some cases and bounded in others. Moreover, we prove that our tests can attain the minimax separation rate according to this measure, up to logarithmic factors. Our methodology does not require any complete cases to be effective, and is available in the R package MCARtest. ------------------------------------------------ Sarà possibile seguire entrambi i seminario anche in streaming: Join Zoom Meeting <https://us02web.zoom.us/j/88246009718?pwd=UnVxL2R5RThwQllDbWVnbTdRNGVMUT09> Il seminario è organizzato dalla "de Castro" Statistics Initiative www.carloalberto.org/stats -- Pierpaolo De Blasi University of Torino & Collegio Carlo Alberto carloalberto.org/pdeblasi <https://sites.google.com/a/carloalberto.org/pdeblasi/>

1 0

Seminar by Dr. Piero Mazzarisi.
by Giorgio Rizzini 24 Feb '23

24 Feb '23

Dear all, we are glad to announce the following seminar by Dr. Piero Mazzarisi (University of Siena) on Tuesday, February 28th 2023 starting from 11:00 in room 4026 at the Department of Statistics and Quantitative Methods, University of Milano-Bicocca (Milan). *Realized Random Graphs, with an application to the Interbank Network* *Piero Mazzarisi* Department of Economics and Statistics University of Siena *Abstract:* This work introduces a new econometric methodology to infer dynamic network models driven by latent state variables. The main idea is to obtain a noisy representation of the state variables dynamics by computing a sequence of cross-sectional estimates of the network model at each point in time. The dynamic modeling of these cross-sectional estimates, that we name realized random graphs, transforms the original nonlinear state-space network model into a linear time-series model that can easily be estimated. Under the assumption that the network is dense, and of a mixed-membership blockmodel structure, we show that the model parameters and the unobservable state variables can be estimated at a super-consistent rate of convergence for large cross sections. By allowing for an extremely rich parameterization of the model in high dimensions, the proposed methodology describes the heterogeneous topology of real-world networks. We corroborate our findings by using this novel framework to estimate and forecast the dynamic common factors driving the evolution of the Italian electronic market of interbank deposits. *February 28th, 2023, 11:00 a.m.* *Department of Statistics and Quantitative Methods* Aula Seminari 4026 - Building U7 (Fourth floor*)* *Bicocca degli Arcimboldi street, 8 – 20126 Milan* For further information, please write to *rosanna.grassi(a)unimib.it <rosanna.grassi(a)unimib.it>*

1 0

Associate professorship Mathematical Physics Bologna
by giacomo.depalma＠sns.it 23 Feb '23

23 Feb '23

Dear all, The Department of Mathematics of the University of Bologna has opened an Associate Professor position in Mathematical Physics. IMPORTANT: Applicants should already hold an equivalent position or have the Italian National Scientific Qualification for Associate Professorship in Mathematics. We are looking for top-level researchers in the fields of Classical Mechanics, Quantum Mechanics or Statistical Mechanics. The Mathematical Physics Group is active in the main areas of the discipline and the Department has a wide spectrum of research interests in all the fields of mathematics and has close collaborations with the Departments of Physics, Computer Science, Engineering, Economics etc. The University of Bologna is renowned to be one of the best in Italy. The city of Bologna offers a broad number of cultural activities and a high quality of life. Link to the call: https://bandi.unibo.it/s/apos4/d-r-n-75-del-25-gennaio-2023-bando-per-la-cop ertura-di-posti-di-professore-di-ii-fascia-ai-sensi-dell-art-18-comma-4-dell a-legge-240-2010 Deadline for applications: March 23, 2023 For further information you are welcome to contact me (giacomo.depalma(a)unibo.it <mailto:giacomo.depalma@unibo.it> ), Prof. Emanuela Caliceti (emanuela.caliceti(a)unibo.it <mailto:emanuela.caliceti@unibo.it> ) or Prof. Daniele Tantari (daniele.tantari(a)unibo.it <mailto:daniele.tantari@unibo.it> ). You are welcome to forward this email to potentially interested candidates. Best, Giacomo

1 0

PhD ECOSTATDATA - Call for applications
by Alessia Caponera 23 Feb '23

23 Feb '23

Dear colleagues, We are glad to announce that five fully funded Ph.D. fellowships in STATISTICS are available within the Ph.D. programme ECOSTATDATA at the University of Milano-Bicocca for the 39th cycle. The Ph.D. program extends over four years (Nov 2023 - October 2027) The first public call for applications will be out from March 21 to April 19, 2023, and the final ranking of candidates will be published in May 2023. Please find attached the pdf file with the call for applications. Best regards, Alessia Caponera

1 0

SPASS Seminars: M. Aleandri and M. Rehmeier
by Francesco Grotto 21 Feb '23

21 Feb '23

Dear Colleagues, We would like to invite you to the following SPASS seminar by Marco Rehmeier (U. Bielefeld) and Michele Aleandri (Sapienza), jointly organized by UniPi, SNS, UniFi and UniSi. The seminars will take place on TUE, 28.2.2023 starting at 14:00 CET in Sala Seminari, Dipartimento di Matematica, Pisa. The seminars will also be broadcasted on Google Meet, follow the link below for the streaming. The organizers, A. Agazzi, G. Bet, A. Caraceni, F. Grotto, G. Zanco https://sites.google.com/unipi.it/spass Marco Rehmeier (Bielefeld University), 14:00 Title: On nonlinear Markov Processes in the sense of McKean Abstract: We study nonlinear Markov processes in the sense of McKean and present a large new class of examples. Our notion of nonlinear Markov property is in McKean's spirit, but more general in order to include examples of such processes whose one-dimensional time marginals solve a nonlinear parabolic PDE, such as Burgers' equation, the porous media equation, or variants of the latter with transport-type drift. We show that the associated nonlinear Markov process is given by path laws of weak solutions to a corresponding distribution-dependent stochastic differential equation whose coefficients depend singularly (i.e. Nemytskii-type) on its one-dimensional time marginals. Moreover, we show that also for general nonlinear Markov processes, their path laws are uniquely determined by one-dimensional time marginals of suitable associated conditional path laws. Furthermore, we characterize the extremality of the curves of the one-dimensional time marginals of our nonlinear Markov Processes in the class of all solutions to the associated linearized PDE and, this way, obtain new interesting results also for the classical linear case. This is joint work with Michael Röckner. Michele Aleandri (Università di Roma La Sapienza), 15:00 Title: Opinion dynamics with Lotka-Volterra type interactions Abstract: We investigate a class of models for opinion dynamics in a population with two interacting families of individuals. Each family has an intrinsic mean field “Voter-like” dynamics which is influenced by interaction with the other family. The interaction terms describe a cooperative/conformist or competitive/nonconformist attitude of one family with respect to the other. We prove chaos propagation, i.e., we show that on any time interval [0; T], as the size of the system goes to infinity, each individual behaves independently of the others with transition rates driven by a macroscopic equation. We focus in particular on models with Lotka-Volterra type interactions, i.e., models with cooperative vs. competitive families. For these models, although the microscopic system is driven a.s. to consensus within each family, a periodic behaviour arises in the macroscopic scale. In order to describe fluctuations between the limiting periodic orbits, we identify a slow variable in the microscopic system and, through an averaging principle, we find a diffusion which describes the macroscopic dynamics of such variable on a larger time scale.

1 0

Seminar by Paolo Di Tella in Padova
by Giorgia Callegaro 20 Feb '23

20 Feb '23

Dear all, you're invited to the next seminar in Probability and Finance that will take place this Friday, at 2.30 pm, in hybrid mode at the Math Dept of the University of Padova. More details: * *Speaker*: Paolo Di Tella (TU Dresda) * *Date and time*: 24th February 2023, 2.30pm * *Room (Torre Archimede)*: 2BC60 * *Zoom link*: please find it here *https://www.math.unipd.it/~bianchi/seminari/* <https://www.math.unipd.it/~bianchi/seminari/> * *Title*: *On the compensator of step processes in progressively enlarged filtrations and related control problems* * *Abstract*: please check the webpage *https://www.math.unipd.it/~bianchi/seminari/* <https://www.math.unipd.it/~bianchi/seminari/> See you there! The organisers A. Bianchi, G. Callegaro, M. Formentin -- Giorgia Callegaro Associate Professor Department of Mathematics - University of Padova Via Trieste 63 , I-35121 Padova - ITALY Tel: +39-0498271481 Fax: +39-0498271499 E-Mail: gcallega(a)math.unipd.it <https://webmail.math.unipd.it/horde3/imp/message.php?mailbox=Sent&index=598#> Personal web-page: https://sites.google.com/site/giogiocallegaro/Home

1 0

avviso di seminario
by Barbara Martinucci 20 Feb '23

20 Feb '23

*UNIVERSITA' DI SALERNO* *Dipartimento di Matematica* AVVISO DI SEMINARIO Venerdì 24 febbraio 2023, alle ore 12:30, nella la Sala del Consiglio del Dipartimento di Matematica, edificio F2, livello 1, si terrà il seguente seminario in presenza e online (su Teams): *Statistical estimation in the models with memory* Prof.ssa *Yuliya Mishura* Department of Probability, Statistics and Actuarial Mathematics, Taras Shevchenko National University of Kyiv, Kyiv (Ukraine) Gli interessati sono cordialmente invitati a partecipare, * Antonio Di Crescenzo* * Barbara Martinucci* * Alessandra Meoli* * Serena Spina* Link su Teams: https://teams.microsoft.com/l/meetup-join/19%3a6hfHOOIVt89PyLIJDpqXis553z6p… *Abstract* We consider mixed fractional Brownian motion with trend and propose the estimators of all parameters. However, the estimators are constructed in different ways for different parameters. Then we consider the numerical estimation of the drift parameter in the linear model with two fBms with different Hurst indices. Numerical construction of MLE is reduced to the numerical solution of the Fredholm integral equation of the 2nd kind with a singular kernel.

1 0

Next OWPS on March 1st: Alan Hammond and Tyler J. Helmuth
by Alberto Chiarini 20 Feb '23

20 Feb '23

OWPS's next session will be on Wednesday the 1s of March of from 15:00 to 17:00 UTC. Our next speakers are: Alan Hammond (Berkeley) and Tyler J. Helmuth (Durham University) Title, abstract and the zoom link are below the signature and can be found on the website https://www.owprobability.org/one-world-probability-seminar. We have found that many that subscribed to the mailing list to receive these updates are not receiving them anymore. If you are interested in the project, we kindly ask you to resubscribe to the mailing list and share this announcement within your community. With best wishes, Alberto Chiarini (Padua) and Adrián González Casanova (Berkeley and México) ----------------------------------------------------------------------------------------------------------- Talk 1 : Alan Hammond (Berkeley) Title : Stake-governed random-turn games Abstract : Many combinatorial games, such as chess, Go and Hex, are zero-sum games in which two players alternate in making moves. In a random turn variant, each player wins the right to move at any given turn according to the flip of a fair coin. In 2007, Peres, Schramm, Sheffield and Wilson [PSSW] found explicit optimal strategies for a broad class of random-turn games, including Hex (which remains unsolved in its alternating-turn form on the 11-by-11 boards in which it is often played in tournaments). In this talk, we discuss stake-governed random-turn games, introduced recently in joint work with Gábor Pete. Two players of Hex are each given a certain limited budget at the outset of the game. At each turn, each stakes some part of what remains of her budget. The ensuing turn is random, with a player winning the right to move according to the proportion that her stake composes of the total stake at the turn. How much should a player stake at any given turn? Opposing pressures compete: stake too little, and lose the turn; too much, and be left with too little for later in the game. So this question concerns how to evaluate the relative strategic importance of intermediate positions in multi-turn games. We answer it for a class of games that are cousins of the random tug-of-war games introduced by PSSW in 2009; these authors forged a connection between game theory and the infinity Laplacian (which is an L^\infty counterpart to the usual L^2 Laplacian), and we will see how, in a discrete context at least, this connection extends to stake-governed random-turn games. Talk 2 : Tyler J. Helmuth (Durham University) Title : The Arboreal Gas Abstract : In Bernoulli bond percolation each edge of a graph is declared open with probability p, and closed otherwise. Typically one asks questions about the geometry of the random subgraph of open edges. The arboreal gas is the probability measure obtained by conditioning on the event that the percolation subgraph is a forest, i.e., contains no cycles. Physically, this is a model for studying the gelation of branched polymers. What are the percolative properties of these random forests? Do they contain giant trees? I will discuss what is known and conjectured. Zoom-link: https://unipd.zoom.us/j/88156851546?pwd=a1NPSkYxRlZoV3dYeERSY3NkV3kvUT09 Meeting ID: 881 5685 1546  Passcode: 718658 If you are having trouble with zoom, or if the capacity of the zoom room gets exceeded, you can also access to the Youtube live stream at the channel of the seminar: https://www.youtube.com/channel/UCiLiEQGTp6bZEhuHDM-WNWQ

1 0

Mi presento
by Marco Zamparo 20 Feb '23

20 Feb '23

Buongiorno a tutti, da qualche ora sono parte di questa vostra lista. Questo breve messaggio è per presentarmi a quelli di voi che ancora non mi conoscono. Mi chiamo Marco Zamparo e sono un fisico teorico "pentito" che da qualche anno si occupa di probabilità e fisica statistica rigorosa. Allego un CV aggiornato per i curiosi. Sto lavorando al modello di pinning dei polimeri con Giambattista Giacomin (Université Paris Cité) e ai processi di rinnovo in ambiente random con Frank den Hollander (Universiteit Leiden). Sono inoltre interessato allo studio del gas di Lévy-Lorentz, del quale ho parzialmente caratterizzato le proprietà di trasporto. Ho un RTDA in fisica teorica e sono in cerca di una posizione in probabilità o fisica matematica per poter completare la "trasformazione". Dati i vincoli Gelmini sugli anni di precariato, sono costretto a considerare solo RTDB o nuovi RTT. Sono in possesso dell'abilitazione scientifica nazionale in fisica matematica (MAT/07) e a maggio chiederò quella in probabilità (MAT/06). Se qualcuno avesse piacere di conoscermi, sarei lieto di fare una presentazione o un seminario. Non vi rubo altro tempo. Grazie per l'attenzione! Buona settimana, Marco

1 0

Fixed term research position (RTDa) in Pisa
by Marco Romito 20 Feb '23

20 Feb '23

dear all I would like to announce a fixed term three years research position (RTD-A) on probabilistic models for the mathematics of machine learning at the Maths Department of University of Pisa. The official call can be found here https://bandi.unipi.it/public/Bandi/Detail/4ad9b281-2731-4170-b0a6-1c2863b0… The position is funded by the PNRR - M4C2 - Investimento 1.3, Partenariato Esteso PE00000013 - "FAIR - Future Artificial Intelligence Research" - Spoke 1 "Human-centered AI", funded by the European Commission under the NextGeneration EU programme. Please contact me in case of further information m.

1 0

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

Random February 2023