Goto

Collaborating Authors

 fonction


Modèles de Fondation et Ajustement : Vers une Nouvelle Génération de Modèles pour la Prévision des Séries Temporelles

Laglil, Morad, Devijver, Emilie, Gaussier, Eric, Pracca, Bertrand

arXiv.org Artificial Intelligence

Inspired by recent advances in large language models, foundation models have been developed for zero-shot time series forecasting, enabling prediction on datasets unseen during pretraining. These large-scale models, trained on vast collections of time series, learn generalizable representations for both point and probabilistic forecasting, reducing the need for task-specific architectures and manual tuning. In this work, we review the main architectures, pretraining strategies, and optimization methods used in such models, and study the effect of fine-tuning after pretraining to enhance their performance on specific datasets. Our empirical results show that fine-tuning generally improves zero-shot forecasting capabilities, especially for long-term horizons.


Implémentation Efficiente de Fonctions de Convolution sur FPGA à l'Aide de Blocs Paramétrables et d'Approximations Polynomiales

Magalhães, Philippe, Fresse, Virginie, Suffran, Benoît, Alata, Olivier

arXiv.org Artificial Intelligence

Implementing convolutional neural networks (CNNs) on field-programmable gate arrays (FPGAs) has emerged as a promising alternative to GPUs, offering lower latency, greater power efficiency and greater flexibility. However, this development remains complex due to the hardware knowledge required and the long synthesis, placement and routing stages, which slow down design cycles and prevent rapid exploration of network configurations, making resource optimisation under severe constraints particularly challenging. This paper proposes a library of configurable convolution Blocks designed to optimize FPGA implementation and adapt to available resources. It also presents a methodological framework for developing mathematical models that predict FPGA resources utilization. The approach is validated by analyzing the correlation between the parameters, followed by error metrics. The results show that the designed blocks enable adaptation of convolution layers to hardware constraints, and that the models accurately predict resource consumption, providing a useful tool for FPGA selection and optimized CNN deployment.


Déréverbération non-supervisée de la parole par modèle hybride

Bahrman, Louis, Fontaine, Mathieu, Richard, Gaël

arXiv.org Artificial Intelligence

This paper introduces a new training strategy to improve speech dereverberation systems in an unsupervised manner using only reverberant speech. Most existing algorithms rely on paired dry/reverberant data, which is difficult to obtain. Our approach uses limited acoustic information, like the reverberation time (RT60), to train a dereverberation system. Experimental results demonstrate that our method achieves more consistent performance across various objective metrics than the state-of-the-art.


Self-supervised learning for phase retrieval

Sechaud, Victor, Abry, Patrice, Jacques, Laurent, Tachella, Julián

arXiv.org Artificial Intelligence

In recent years, deep neural networks have emerged as a solution for inverse imaging problems. These networks are generally trained using pairs of images: one degraded and the other of high quality, the latter being called 'ground truth'. However, in medical and scientific imaging, the lack of fully sampled data limits supervised learning. Recent advances have made it possible to reconstruct images from measurement data alone, eliminating the need for references. However, these methods remain limited to linear problems, excluding non-linear problems such as phase retrieval. We propose a self-supervised method that overcomes this limitation in the case of phase retrieval by using the natural invariance of images to translations.


Photometric Stereo using Gaussian Splatting and inverse rendering

Ducastel, Matéo, Tschumperlé, David, Quéau, Yvain

arXiv.org Artificial Intelligence

Recent state-of-the-art algorithms in photometric stereo rely on neural networks and operate either through prior learning or inverse rendering optimization. Here, we revisit the problem of calibrated photometric stereo by leveraging recent advances in 3D inverse rendering using the Gaussian Splatting formalism. This allows us to parameterize the 3D scene to be reconstructed and optimize it in a more interpretable manner. Our approach incorporates a simplified model for light representation and demonstrates the potential of the Gaussian Splatting rendering engine for the photometric stereo problem.


O_FT@EvalLLM2025 : étude comparative de choix de données et de stratégies d'apprentissage pour l'adaptation de modèles de langue à un domaine

Rousseau, Ismaël, Perroux, Claire, Adam, Pierre, Girault, Thomas, Delphin-Poulat, Lionel, Veyret, Morgan, Lecorvé, Gwénolé, Damnati, Géraldine

arXiv.org Artificial Intelligence

This paper presents the work carried out by the O_FT team, joint with Orange and Ouest-France, on adapting language models to the defense domain as part of the EvalLLM2025 challenge. This work focused on adapting the \texttt{Mistral-7B-Instruct-v0.3} model using classical techniques of continued pre-training and instruction-tuning. The core of our efforts is based on collecting, generating, and selecting data for these two stages as well as for model evaluation. Experiments show that our adapted models have better domain-specific knowledge and improved domain-specific task processing skills, along with comparable (or even superior) performance on general knowledge and skills. Considering the carbon footprint of our adaptations, this work demonstrates the feasibility of domain adaptation for relatively small models. -- Ce document présente les travaux réalisés par l'équipe O_FT conjointe à Orange et Ouest-France sur l'adaptation de modèles de langue au domaine de la défense dans le cadre du challenge EvalLLM2025. Ces travaux se sont concentrés sur l'adaptation du modèle \texttt{Mistral-7B-Instruct-v0.3} avec des techniques classiques de poursuite du pré-entraînement et d'affinage sur instructions. L'essentiel de nos travaux a porté sur la constitution, génération et sélection de données pour ces deux étapes ainsi que pour l'évaluation des modèles. Les expériences montrent que nos modèles adaptés ont de meilleures de connaissances de fond et une meilleure capacité de traitement de tâches sur le domaine de la défense, ainsi que des performances comparables (voire supérieures) sur des connaissances ou capacités généralistes. Mis au regard des empreintes carbones de nos adaptations, ces travaux démontrent ainsi la viabilité de l'adaptation à un domaine de modèles relativement petits.


Méthode de quadrature pour les PINNs fondée théoriquement sur la hessienne des résiduels

Caradot, Antoine, Emonet, Rémi, Habrard, Amaury, Mezidi, Abdel-Rahim, Sebban, Marc

arXiv.org Artificial Intelligence

Physics-informed Neural Networks (PINNs) have emerged as an efficient way to learn surrogate neural solvers of PDEs by embedding the physical model in the loss function and minimizing its residuals using automatic differentiation at so-called collocation points. Originally uniformly sampled, the choice of the latter has been the subject of recent advances leading to adaptive sampling refinements. In this paper, we propose a new quadrature method for approximating definite integrals based on the hessian of the considered function, and that we leverage to guide the selection of the collocation points during the training process of PINNs.


Pr{é}diction optimale pour un mod{è}le ordinal {à} covariables fonctionnelles

Weinberger, Simón, Cugliari, Jairo, Cain, Aurélie Le

arXiv.org Artificial Intelligence

We present a prediction framework for ordinal models: we introduce optimal predictions using loss functions and give the explicit form of the Least-Absolute-Deviation prediction for these models. Then, we reformulate an ordinal model with functional covariates to a classic ordinal model with multiple scalar covariates. We illustrate all the proposed methods and try to apply these to a dataset collected by EssilorLuxottica for the development of a control algorithm for the shade of connected glasses.


Modèles de Substitution pour les Modèles à base d'Agents : Enjeux, Méthodes et Applications

Saves, Paul, Verstaevel, Nicolas, Gaudou, Benoît

arXiv.org Artificial Intelligence

Multi-agent simulations enables the modeling and analyses of the dynamic behaviors and interactions of autonomous entities evolving in complex environments. Agent-based models (ABM) are widely used to study emergent phenomena arising from local interactions. However, their high computational cost poses a significant challenge, particularly for large-scale simulations requiring extensive parameter exploration, optimization, or uncertainty quantification. The increasing complexity of ABM limits their feasibility for real-time decision-making and large-scale scenario analysis. To address these limitations, surrogate models offer an efficient alternative by learning approximations from sparse simulation data. These models provide cheap-to-evaluate predictions, significantly reducing computational costs while maintaining accuracy. Various machine learning techniques, including regression models, neural networks, random forests and Gaussian processes, have been applied to construct robust surrogates. Moreover, uncertainty quantification and sensitivity analysis play a crucial role in enhancing model reliability and interpretability. This article explores the motivations, methods, and applications of surrogate modeling for ABM, emphasizing the trade-offs between accuracy, computational efficiency, and interpretability. Through a case study on a segregation model, we highlight the challenges associated with building and validating surrogate models, comparing different approaches and evaluating their performance. Finally, we discuss future perspectives on integrating surrogate models within ABM to improve scalability, explainability, and real-time decision support across various fields such as ecology, urban planning and economics.


Design and use of devices to assist movement of the upper limb: review of the literature

Goff, Charlotte Le, Coignard, Pauline, Azevedo-Coste, Christine, Geffard, Franck, Fattal, Charles

arXiv.org Artificial Intelligence

This article explores assistive devices for upper limb movement in people with disabilities through a systematic review based on the PRISMA methodology. The studied devices encompass technologies ranging from orthoses to advanced robotics, aiming to compensate for or supplement motor impairments. The results highlight the diversity of applications (rehabilitation, daily living activities), targeted body segments (distal, proximal, or global), as well as control mechanisms and interfaces used. However, despite the variety of promising prototypes, few devices are commercially available, limiting their real impact on end users. Existing technologies, while effective in improving functional autonomy and quality of life, still face challenges in terms of ergonomics, cost, and portability. In conclusion, this article emphasizes the importance of a user-centered approach and proposes avenues for the development of innovative, modular, and accessible assistive devices.