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Séminaire AFRIMath de Probabilités et Statistiques

Organisation : Jean-François Dupuy (INSA de Rennes), Ouagnina Hili (Institut National Polytechnique Félix Houphouët-Boigny), Solym Manou-Abi (LMA-Université de Poitiers),
Vous trouverez ci-dessous les séminaires archivés. Cliquez ici pour retrouver l'ensemble des séminaires à venir.
Ridge-penalized Zero-Inflated Probit Bell model for multicollinearity in count data

In this we develops a ridge estimator for the Zero-Inflated Probit Bell (ZIPBell) regression model. The ZIPBell model adapts the Zero-Inflated Bell (ZIBell) model originally proposed by Lemonte et al. (2019) by employing a probit link function for the zero-inflation component. Our contribution lies in incorporating ridge penalization into this framework, providing a methodology that stabilizes parameter estimates by reducing variance and mitigating multicollinearity effects without excluding correlated predictors.

jeu 09/10/2025 - 15:00 - jeu 09/10/2025 - 16:00
Une approche de modélisation semi-markovienne fondée et guidée par les données. Un exemple sur le traitement des données de Covid-19 à Madagascar.

Résumé

jeu 24/07/2025 - 14:00 - jeu 24/07/2025 - 15:00
A New Topp–Leone Kumaraswamy based family of distributions: Properties, inequality measures and applications to socio economic development indicators

We introduce a new family of distributions based on Topp–Leone Kumaraswamy, designed for data modeling. We analyze its mathematical properties, moments, and stochastic characteristics, proposing a parameter estimation method using maximum likelihood. The model’s applicability is demonstrated through data on development indicators in Benin, compared with competing models. The promising results highlight the relevance of this new family for statistical analysis and decision-making in socio- economic development.

Expose-Nicodeme.pdf (142.61 Ko)
jeu 27/02/2025 - 16:00 - jeu 27/02/2025 - 17:00
Extreme quantile estimation for censored heavy-tailed data

Bayesian estimation of the tail index of a heavy-tailed distribution is addressed when data are randomly right-censored. Maximum a posteriori and mean posterior estimators are constructed for various prior distributions of the tail index. Their finite-sample properties are investigated via simulations. Tail index estimation requires selecting an appropriate threshold for constructing relative excesses. A Monte Carlo procedure is proposed for tackling this issue. Finally, the proposed estimators are illustrated on a medical dataset.

mer 13/12/2023 - 17:00 - mer 13/12/2023 - 18:15
Estimation of zero-inflated bivariate Poisson regression with missing covariates
mer 15/11/2023 - 17:00 - mer 15/11/2023 - 18:15
Strong approximate solutions for Stable-driven Stochastic Differentials Equations

We consider in this paper, a general class of stochastic differential equations driven by stable processes with Lipschitz drift  coefficients and non-Lipschitz diffusion coefficients. A strong Euler-Maruyama approximate  solution  is proved whenever the diffusion coefficient is  Hölder continuous with exponent satisfying some condition.  We derive also the  strong rate of convergence.

mer 11/10/2023 - 18:00 - mer 11/10/2023 - 19:15
Calculs éfficaces des ensembles de prédictions conformes
Eugene-Expose.pdf (99.75 Ko)
mer 12/07/2023 - 16:30 - mer 12/07/2023 - 17:30
Parameter estimation in a hidden birth and death process with immigration

In this talk, we consider a linear birth and death process with immigration to model infectious disease propagation when contamination stems from both person-to-person contact and the environment. Our aim is to estimate the parameters

mer 07/09/2022 - 16:00 - mer 07/09/2022 - 17:00
M-estimates for univariate stationary hyperbolic GARCH models and applications
Resume_Lancine.pdf (106.96 Ko)
mer 29/06/2022 - 16:00 - mer 29/06/2022 - 17:00
Time-varying regression coefficients for semi-Markovian Model : Application to malaria serological and Covid 19

Time homogeneous Markov model has been successfully used to extend the
clas sical survival analysis to the multi-states analysis. This model assumes
that the evolution of the process is independent to the waiting time in the state.
In our clinical problem, this constraint is restrictive. The semi-Markov can be
used to extend the time-homogeneous Markov model with discrete states and

Abstract_Oumy.pdf (37.02 Ko)
mer 16/03/2022 - 16:30 - mer 16/03/2022 - 17:30
Mesures de dépendance dans le contexte des vecteurs aléatoires symétriques alpha-stables
résumé (122.38 Ko) , exposé (427.07 Ko)
mer 08/12/2021 - 16:00 - mer 08/12/2021 - 17:00
Non-pharmaceutical interventions and COVID-19 vaccination strategies in low- and middle-income countries: a modelling study in Senegal
Diarra_et_al.pdf (203.27 Ko)
mer 10/11/2021 - 16:00 - mer 10/11/2021 - 17:00
Modèles d’épidémies en espace discret et continu. Loi des grands nombres et fluctuations
résumé (115.38 Ko) , exposé (497.16 Ko)
mer 07/07/2021 - 16:00
Estimation of Actuarial Risk Measures from heavy Tailed Losses
résumé (94.09 Ko) , exposé (437.05 Ko)
mer 02/06/2021 - 16:00
Régression de Poisson censurée en présence d'indicatrices de censure manquantes
résumé (106.51 Ko) , exposé (446 Ko)
mer 05/05/2021 - 16:00

Activités à venir

Conférences
AFRIMath 2026 -- First conference of the MaGA project (Mathematics in Gabon for Africa)

L'évènement se deroulera le 13/04/2026
Cap Skirring, Sénégal
de 09:00 à 17:00

Partenaires

  • Nantes Université
  • CNRS
  • LMJL
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