Education

• Ph.D. candidate, Université de Montpellier, Applied Math. 2022-present.
• M.Sc., Sorbonne Université (Paris VI), Applied Math. 2021-2022.
• M.Sc., Institut de Mathématiques et de Sciences Physiques (IMSP), Fundamental Math. 2018-2020.

Ph.D. Thesis

Estimation and control for a system of interconnected bioreactors for the reuse of treated wastewater in agriculture

I started my Ph.D degree in September 2022. My work aims to develop control methods to pilot an original system of three interconnected bioreactors to reuse wastewater in agriculture. More particularly, it is a problem called "setpoint tracking", such "setpoint" being the result of the resolution of an optimal control problem solved using a crop irrigation model. However, optimal solutions should be expressed as feedback that depends on the nitrogen in the soil, which a priori is not available. Another difficulty is related to the various uncertainties in the model parameters. We propose to bring concrete answers to these challenges by designing the so-called "adaptive observer" for the joint estimation of nitrogen and uncertain parameters.

Publications

• Dadjo, M.G., Rapaport, A., Harmand, J., Ushirobira, R., Efimov, D. (2025). A robust adaptive observer for a class of nonlinear time-varying systems with application to a crop fertigation model.
  Submitted.
• Dadjo, M.G., Rapaport, A., Harmand, J., Ushirobira, R., Efimov, D. (2024). Synthesis of optimal control under state constraints for crop fertigation.
  Submitted.
• Dadjo, M.G., Rapaport, A., Harmand, J., Ushirobira, R., Efimov, D. (2024). Practical observability and observers for nonlinear systems subject to bounded disturbances.
  Accepted to ECC 2025.
• Dadjo, M.G., Rapaport, A., Harmand, J., Ushirobira, R., Efimov, D. (2024). Minimal Water Consumption for a Crop Fertirrigation Model.
  Proceedings of the 2024 European Control Conference (ECC), Stockholm, Sweden, IEEE, pp. 2380–2385.
  DOI: 10.23919/ECC64448.2024.10591095
• Dadjo, M.G., Efimov, D., Harmand, J., Rapaport, A., Ushirobira, R. (2023). An Adaptive Observer for Time-Varying Nonlinear Systems - Application to a Crop Irrigation Model.
  Proceedings of the 2023 IEEE Conference on Decision and Control (CDC), Singapore, IEEE, pp. 7489–7494.
  DOI: 10.1109/CDC49753.2023.10384304

Communications

• Presentation at European Control Conferences, June 2024, Stockholm, Sweden Minimal Water Consumption for a Crop Fertirrigation Model.
  
• REUSE EUROMED 2024, Euro-Mediterranean Conference on Wastewater Reuse, October 2024, Montpellier, France Contribution of viability theory and constrained optimal control to fertigation.
  PDF DIASPORAMA
• Journée annuelle Gdr MOA, October 2023, Perpignan, France Stratégies de minimisation de la quantité d’eau sous contraintes de viabilité pour un modèle de fertirigation des cultures.
  
• AG Réseau REUSE INRAE, October 2024, Avignon, France Otimization of fertirigation practice: An approach based on viability theory and optimal control.
  PDF
• Seminar G-eau, December 2024, Montpellier, France Nitrogen optimization in agriculture-reuse.
  

Research Interests

• Control Systems, Optimal Control, Optimization, Mathematical Modeling, Estimation (states and parameters)
• Specific: Pontryagin Maximum Principle (PMP) and Applications, Observers design for nonlinear systems, ISS-stability, Linear Matrix Inequality (LMI)

Teaching

HA8401H - Differential Calculus and Multivariable Integration

2nd Year B.Sc, Polytech Montpellier Engineering School, 2024

Documents

• Course Notes
• TD1 - Introduction and Basic Concepts (Worksheet)
• TD2 - Parametric Curves (Worksheet)
• TD3 - Geometry and Topology in \(\mathbb{R}^n\) (Worksheet )
• TD4 - Differential Calculus (Worksheet)
• TD5 - Multiple Integrals (Worksheet)

Course Content

1) Introduction and Basic Concepts

Introduction to multivariable functions: definitions, examples, graphs, level sets, partial functions, vector functions, and parametric curves.

2) Parametric Curves

Analysis of vector functions with a single variable, parametric curves, length, curvature, analysis of parametric arcs.

3) Geometry and Topology in \(\mathbb{R}^n\)

Norms and distances, limits of sequences and functions, continuity, elementary topology, scalar product, and Euclidean norm.

4) Differential Calculus in \(\mathbb{R}^n\)

Differentiability, partial derivatives, gradient vector, Jacobian matrix, \(\mathcal{C}^1\) functions, higher-order derivatives, Taylor series, Hessian matrix.

5) Multiple Integrals

Review of single integrals, double and triple integrals, change of variables formula, circulation of vector fields.

Responsable: Philippe Castillon

HAS202X - Mathematical Tools III

First Year B.Sc, PCSI - Physics, Chemistry, and Engineering Sciences, 2022-2023 and 2023-2024

Documents

• Course Notes
• Exam 2024
• TD2 (Worksheet)

Course Content

1) Matrices

Sum and Outer Product, Transposition, Matrix Product, Mixed Properties, Matrix Power, Trace.

2) The Spaces \( \mathbb{R}^n \) and \( \mathbb{C}^n \)

Geometric Interpretations, \( \mathbb{R}^2 \) and the Usual Euclidean Plane, Matrix Product and Dot Product, Matrix Product and Cross Product, Notion of Vector Subspace, Generated Subspace, List of Vector Subspaces of \( \mathbb{R}^n \) for \( n = 1, 2, 3 \), Notion of Affine Subspace.

3) Linear Systems

Systems, Vector Subspaces, and Affine Subspaces, Gaussian Elimination Algorithm, Solution Space - Summary of the Resolution Method, Special Case of a Homogeneous System.

4) Invertibility and Determinant

Invertible Matrices, Determinants, Practical Calculation of the Inverse.

5) Bases and Linear Mapping

Bases of \(\mathbb{R}^n\), Change of Basis, Operations on Linear Mappings, Matrices and Linear Mappings, Matrix Representation of a Linear Mapping in a Basis.

6) Diagonalization

Eigenvalues, Characteristic Polynomial, Computing Eigenvectors, Eigenvalues and Linear Mappings.

7) Equations and First-Order Linear Differential Systems

First-Order Linear Differential Equations, First-Order Linear Differential Systems with Constant Coefficients, Curves in \(\mathbb{R}^n\).

Responsable: Laurent Guieu

Research Projects

• Co-leader of the BOUM SMAI Project for Young Researchers, (with Anas Bouali and Ruben Chenevat). Organization of a conference day on Optimization, Modeling, and Controlat INRAE Occitanie-Montpellier (upcoming in 2025)BOUge tes Math ́ematiques (BOUM) – a project funded by the French Society of Applied andIndustrial Mathematics (SMAI) and partially supported by Inria.Objective: To foster networking, collaboration, and dynamism among young researchers inApplied Mathematics through organizing conferences, workshops, and research-oriented activ-ities.

Work Experience

• Research internship, L2S CentraleSupélec, Gif-sur-Yvette, May-September. 2021.
• Ph.D. Research, INRAE, MISTEA team, Montpellier, September. 2022-present.
• Ph.D. Research, Inria, VALSE team, Lille, September. 2022-present.

Computer Skills

• SCILAB, MATLAB, Julia controltoolbox, LaTeX

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