Régis SABBADIN

Régis Sabbadin has been a research scientist in the Applied Mathematics and Computer Science laboratory  in Toulouse, since 1999.

Brief bio

Diplomas:

• "Habilitation à diriger des Recherches" from the University of Toulouse,
  on Models and algorithms for sequential decision under uncertainty in 2009.
• PhD degree in Computer Science from the University of Toulouse,
  on An ordinal approach to decision under uncertainty: Axiomatization, logical representation and application to sequential decision-making in 1998.  
  
• Engineer degree in aeronautics from the ENSICA school (now ISAE) in Toulouse in 1993.

Research Domain

My research focuses on Artificial Intelligence methods for automated decision in sequential decision problems under uncertainty,
with applications to agricultural and natural resource management problems. The research issues are :

• Decision theory and algorithms:
  • (sequential) decision under uncertainty, reinforcement learning
  • multi-agent decision problems, game theory,
  • qualitative decision under uncertainty.
• Application to the management of biodiversity, ecosystem services, pest control:
  • management of structured ecosystems: spatial ecosystems, ecological interaction networks,
  • inference of ecosystems structure: sampling optimisation and maps reconstruction, ecological networks inference,
  • biodiversity conservation, ecosystem services optimization, pests control.

The methods developed for both research issues rely, more or less heavily, on the Markov Decion Processes framework and extensions.

Selected recent publications

Methodological papers

Algorithmic game theory

• Fargier (H.), Jourdan (P.), Sabbadin (R.). A Path-following Polynomial Equations Systems Approach for Computing Nash Equilibria.
  In: Proc.of the 21st International Conference on Autonomous Agents and Multiagent Systems (AAMAS 2022).
• Ben Amor (N.), Fargier (H.), Sabbadin (R.), Trabelsi (M.). Solving possibilistic games with incomplete information.
  In International Journal of Approximate Reasoning, 2022.
• Azzabi (A.), Ben Amor (N.), Fargier (H.), Sabbadin (R.). Ordinal graph-based games. In IPMU 2020.

Qualitative decision under uncertainty

• Ben Amor (N.), El Khalfi (Z.), Fargier (H.) and Sabbadin (R.). Lexicographic refinements in possibilistic decision trees and finite-horizon Markov decision processes,
  Fuzzy Sets and Systems,2018,
• Ben Amor (N.), Fargier (H.) and Sabbadin (R.). Equilibria in Ordinal Games: A Framework based on Possibility Theory.
  Proceedings of the 26th International Joint Conference on Artificial Intelligence, pp. 105-111, 2017.
• Ben Amor (N.), El khalfi (Z.), Fargier (H.) and Sabaddin (R.). Efficient Policies for Stationary Possibilistic Markov Decision Processes.
  Symbolic and Quantitative Approaches to Reasoning with Uncertainty. ECSQARU 2017. Lecture Notes in Computer Science, vol 10369. Springer.

Ecosystems management and agriculture

• Cros (MJ.), Aubertot (JN.), Gaba (S.), Reboud (X.), Sabbadin (R.), Peyrard (N.). Improving pest monitoring networks using a simulation-based approach to contribute to pesticide reduction.
  In Theoretical population biology 141, 2021.
• Couture (S.), Cros (MJ.), Sabbadin (R.). Multi-objective sequential forest management under risk using a markov decision process-pareto frontier approach.
  In Environmental Modeling & Assessment 26 (2), 2021.
• Gésan-Guiziou (G.), Alaphilippe (A.), Aubin (J.), Bockstaller (C.), Boutrou (R.), Buche (P.), Collet (C.), Girard (A.), Martinet (V.), Membré (JM.), Sabbadin (R.), Thiollet-Scholtus (M.), van der Werf (HMG.). Diversity and potentiality of multi-criteria decision analysis methods for agri-food research.
  In Agronomy for Sustainable Development 40 (6), 2020.

For a more comprehensive list of publications.

Software

MDP toolbox

A Matlab/Scilab/Octave/R toolbox grouping MDP solution utilities.

Authors: Chades I., Chapron G., Cros MJ., Garcia F., Sabbadin R.

 Paper: Chades I., Chapron G., Cros MJ., Garcia F., Sabbadin R. (2014). MDPtoolbox: a multi-platform toolbox to solve stochastic dynamic programming problems.
Ecography 37:916-920.

GMDP toolbox

A Matlab toolbox grouping GMDP representation and solution utilities.

Authors: Cros MJ, Peyrard N., Sabbadin R.

 Paper: Cros (M.J.), Aubertot (J.N.), Peyrard (N.) and Sabbadin (R.). GMDPtoolbox: A Matlab library for designing spatial management policies.
Application to the long-term collective management of an airborne disease. PLoS ONE 12(10), 2017.

GM toolbox

Authors: Cros MJ, Peyrard N., Sabbadin R.

GTNash toolbox

A Python/Sagemath toolbox proposing normal form, succinct and incomplete information games modeling tools and Nash equilibrium computation utilities.
The toolbox relies on the Sagemath software system.

'Authors: Casellas, E., Chabrier, P.Jourdan, P., Sabbadin R.  Paper Fargier (H.), Jourdan (P.) and Sabbadin (R.). A Path-following Polynomial Equations Systems Approach for Computing Nash Equilibria. Proc' of AAMAS, 2022.

Project participations

• Franch ANR project HSMM-INCA (Hidden Semi Markov Models: INference, Control and Applications), 2022-2026.
• French ANR project PROBITY (Modulating the gene networks underlying phenotypic robustness in plant quantitative immunity), (2019-2022).

PhD Students and Post-docs

PhD students

• Paul Jourdan (PhD), cosupervised with H. Fargier (IRIT-Université de Toulouse). Algorithmique des jeux succincts et à information incomplète, Université Toulouse III, ED MITT (2019-2022).
• Arij Azzabi (PhD), cosupervised with N. Ben Amor (ISG, Tunis) and H. Fargier (IRIT-Université de Toulouse). Représentation compacte des jeux ordinaux.
  ISG-Tunis et Université Toulouse III (2018-2021).
• Etienne Auclair (PhD), cosupervised with N. Peyrard (INRA-MIA, Toulouse).
  Apprentissage de structure d'un réseau écologique mal connu pour la conservation de la biodiversité,
  Université Toulouse III, ED MITT (2015-2018).
• Hui Xiao (PhD), cosupervised with E. McDonald-Madden (University of Queensland) and I. Chadès (CSIRO).
  Optimal management of both ecosystem services and biodiversity, using network theory,
  University of Queensland, school of Geography, Planning and Environmental Management (2015-2018).
• Julia Radoszycki (PhD), cosupervised with S. Gaba (INRA-SPE, Dijon) and N. Peyrard (INRA-MIA, Toulouse).
  Méthodes de conception par optimisation de stratégies spatiales de gestion de communautés de plantes adventices,
  Université Toulouse III, ED MITT(2012-2015).
• Mathieu BONNEAU (PhD), cosupervised with S. Gaba (INRA-SPE, Dijon) and N. Peyrard (INRA-MIA, Toulouse).
  Développement d'une méthode adaptative d'échantillonnage spatialisé pour caractériser la composition du stock semencier
  des espèces adventices à l'échelle de la mosaïque paysagère, Université Toulouse III, ED MITT(2009-2012).
• Nicklas FORSELL (PhD) with F. Garcia (INRA-MIA, Toulouse), L.-O. Eriksson (SLU, Umea, Sweden) and P. Wikström (SLU, Umea, Sweden).
  MDP Approaches for Complex Forest Planning Under Uncertainty, SLU, Umea (2005-2009).
• Nasolo RAVOANJANAHARY (PhD) with J. Lang (CNRS-UPS, Toulouse). Processus décisionnels épistémiques et élicitation interactive de préférences,
  Université Toulouse III, ED MITT (2004-2008).

Post-Docs

• Lise Pomiès, co-supervised with F. Garcia and N. Peyrard.
  Modifications du transcriptome du champignon pathogène S.scle lors de l’infection de différentes plantes hôtes, 2020-2022.
• Yann Dujardin, co-supervised with N. Peyrard (INRA-MIAT) and A. Vialatte (INRA-DYNAFOR).
  Multi-objective optimization applied to the management of landscapes provisioning several ecosystem services. Post-doc INRA-AgreenSkills, 2017-2019.

Teaching

I have a regular but light teaching activity (~ 15h each year). This teaching activity is linked to my research fields (operations research and decision under uncertainty).
A significant part of this teaching activity has been directed to foreign students. From 2014 on, I have decided to decrease  my teaching activities.

Recent past teaching experience :

• MOOC Gestion Agroécologique de la Santé des Cultures et des Organismes Nuisibles (GASCON).
  3 vidéos tournées dans le grain 3 "Approches de modélisation pour la gestion agroécologique des stress biotiques:
  • "Gestion du compromis entre services écosystémiques à l'échelle du paysage : cas Cultures / Adventices / Pollinisateurs".
  • "Un cadre pour la gestion du compromis entre services écosystémiques à l'échelle du paysage: Processus Décisionnels de Markov".
  • "Modélisation du problème Culture / Adventices / Pollinisateurs dans le cadre des PDM factorisés".
• Enseignement doctoral (ISG Tunis), Processus Décisionnels de Markov, ~20h (2017).
• Master 2 Biostatistique et Modélisation, (UPS, Toulouse). Processus Décisionnels de Markov, 15h/year (2005-2014 et 2016).