Offre en lien avec l’Action/le Réseau : BigData4Astro/– — –

Laboratoire/Entreprise : Centre Astrophysique de Lyon
Durée : 5 months
Contact : eric.thiebaut@univ-lyon1.fr
Date limite de publication : 2025-03-01

Contexte :

Sujet :
Internship supervisors: Eric Thiébaut, Michel Tallon
@ : eric.thiebaut@univ-lyon1.fr, mtallon@obs.univ-lyon1.fr

Address/Workplace: CRAL – site Charles André : 9 avenue C. André, St Genis Laval

Hosting research team: AIRI

Internship title: Adaptive optics control and learning

Summary of proposed work:

Context: Adaptive optics (AO) systems are used by most if not all current large telescopes to counteract the effects of the turbulence on the image quality and achieve diffraction limited angular resolution (i.e. λ/D). AO systems work by sensing the wavefront after its correction by a deformable mirror whose shape is controlled considering the departure of the measured wavefront to the ideal one (e.g. a flat wavefront). The AiRi team at CRAL is leading a project, UPCAO (funded by the French ANR), targeted at developing better algorithms and methods to control in real time (i.e. faster than 1,000 times per second) the shape of the wavefront given measurements by a wavefront sensor (WFS). The objective is to provide optimal wavefront correction under varying observing conditions for the THEMIS AO system, for SAXO+, and for future AO systems on ELTs. There are several ideas to improve current AO control systems: (i) improve the model of the AO system, (ii) account for the variable and uneven quality of the WFS measurements notably the fact that not all measures are always valid, and (iii) account for the spatio-temporal statistics of the turbulence to anticipate its evolution and reduce the effects of the delay between the times of measurements and of the correction by the mirror.

Research directions:
Modeling the AO system: To compute the wavefront correction, AO real time controllers assume a model of the behavior of the components of the AO system notably the wavefront sensor (WFS) and the deformable mirror (DM). Intuitively, the closer the model to reality the better the correction. The behavior of the instrument may be complicated (non-linear) and depends on the operating conditions. It is thus important to develop flexible models whose parameters can be calibrated and updated while the AO system is running (in closed-loop). We are currently considering affine approximations of the possibly non-linear behavior of the system that can be calibrated in real-time by a perturbative method. Another possibility to investigate is to exploit deep learning to automatically build the structure of a general non-linear model and to learn its parameters in real-time.
Wavefront reconstruction: For a linear wavefront sensor (WFS), the reconstruction of the wavefront shape given the measurements and accounting for their uneven quality amounts to solving an inverse problem which has a closed-form solution. For large systems, this solution may be computed in real-time by means of accelerated iterative methods [1]. For new non-linear WFS, fast reconstruction methods compatible with the constraints of real-time have to be developed and AI based methods are emerging as competitive candidates.
Modeling and learning the spatio-temporal behavior of the turbulence: Prediction of the temporal evolution of the wavefront is the key to compensate for the delay between the acquisition of wavefront sensor (WFS) measurements and the time at which the shape of the deformable mirror (DM) can effectively account for these measurements. We are developing a fast approximation of the covariance [2] that can be exploited to learn and apply the spatio-temporal statistics of the wavefront. Another possibility is to develop AI based methods.

[1] Béchet+, “Comparison of minimum-norm maximum likelihood and maximum a posteriori wavefront reconstructions for large adaptive optics systems’’ in J. Opt. Soc. Am. A, 26, 497-508 (2009) https://doi.org/10.1364/JOSAA.26.000497
[2] Thiébaut+, “Beyond FRiM, ASAP: a family of sparse approximation for covariance matrices and preconditioners.” Adaptive Optics Systems VIII. Vol. 12185. SPIE, 2022, https://arxiv.org/pdf/2311.17721

Nature of the financial support for the internship: Labex LIO or team funding

Potential for a follow-up as a PhD thesis: Yes

Profil du candidat :
Background in signal processing, numerical methods or related fields.

Formation et compétences requises :

Adresse d’emploi :
Centre de Recherche Astrophysique de Lyon
9 avenue Charles André
69230 Saint-Genis-Laval

Document attaché : 202411181118_FicheStage_CRAL_2024_AIRI_Thiebaut.pdf

Offre en lien avec l’Action/le Réseau : BigData4Astro/– — –

Laboratoire/Entreprise : Centre Astrophysique de Lyon
Durée : 5 months
Contact : olivier.flasseur@univ-lyon1.fr
Date limite de publication : 2025-03-01

Contexte :

Sujet :
Internship supervisors: Olivier Flasseur, Eric Thiébaut, Maud Langlois
@ : olivier.flasseur@univ-lyon1.fr, eric.thiebaut@univ-lyon1.fr, maud.langlois@univ-lyon1.fr

Address/Workplace: CRAL – site Charles André : 9 avenue C. André, St Genis Laval

Hosting research team: AIRI

Internship title: Direct detection and characterization of exoplanets: statistical learning, multi-epoch and multi-spectral data fusion

Summary of proposed work:

Context: The direct observation of the close environment of stars can reveal the presence of exoplanets and circumstellar disks, providing crucial information for a better understanding of planetary system formation, evolution, and diversity. Given the very small angular separation with respect to the host star and the huge contrast between the (bright) star and the (faint) exoplanets and disks, imaging the immediate vicinity of a star is extremely challenging. In addition to the use of extreme adaptive optics and a coronagraph, dedicated post-processing methods combining images recorded with the pupil tracking mode of the telescope are needed to efficiently suppress the nuisance component (speckles and noise) corrupting the signals of interest.
Beyond optimal post-processing of individual observations, fusing multiple observations of the same star taken over different epochs can significantly improve the detection sensitivity. The key challenge in this approach lies in accounting for both the nuisance statistics and the orbital motion of the exoplanet across epochs. To address this, the PACOME algorithm (for PACO Multi-Epoch; [1]) has been recently introduced. PACOME leverages statistical modeling of the nuisance component and its correlations at the local scale within a small pixel patch. This approach is inherited from the PACO algorithm, specifically designed for exoplanet detection from individual (mono-epoch) dataset of observations. The by-products of PACO from each epoch provide sufficient statistics that can be optimally combined using PACOME, while efficiently exploring the Keplerian motion of exoplanets. This multi-epoch strategy yields a combined detection score that is directly interpretable as a measure of detection confidence. In addition to improving sensitivity, PACOME enables the estimation of orbital parameters, along with their joint and marginal distributions. Although PACOME achieves state-of-the-art performance, there remains room for improvement, especially near the star. Here, the assumption of a local-scale statistical description of the nuisance component overlooks larger-scale spatial correlations, thus limiting the method’s detection sensitivity.
In this context, data science developments are decisive to improve the detection sensitivity of exoplanets and the accuracy of the estimation of their orbit.

Research directions: This project will build on recent advancements in modeling the nuisance component that corrupts high-contrast total intensity observations. The focus will be on improving exoplanet detection and characterization. Possible research directions include:
1/ Modeling large-scale nuisance correlations: To address the limitations discussed, the goal is to integrate a more refined modeling of the nuisance component within multi-epoch detection algorithms. This can be achieved using the ASAP approach [2], which approximates the precision matrix (i.e., inverse of the covariance matrix) with a structured, sparse model that may better capture large-scale correlations compared to PACO.
2/ Joint spatio-spectral modeling of large-scale correlations: Building on point 1/, the objective is to develop a joint spatio-spectral model of the nuisance that accounts for large-scale correlations across both spatial and spectral dimensions.

Data: The project will focus on developing / improving new processing algorithms using spectroscopic total intensity observations (i.e., spatio-temporal-spectral data recorded with an Integral Field Spectrograph) from the SPHERE instrument, currently operating on the Very Large Telescope (VLT). Several multi-epochs observations are available to both ground the performance of the proposed algorithm and to search for new exoplanets!
Once a proof of concept is established, simulations for HARMONI, one of the first-light instruments of the upcoming Extremely Large Telescope (ELT), may be considered. In this case, the algorithm will be adapted to account for HARMONI’s specific features, particularly its higher spectral resolution. Achieving the required contrast with this instrument will require extended total exposure times on a single star, making a multi-epoch strategy indispensable.

Bibliography:
[1] Dallant+, “PACOME: Optimal multi-epoch combination of direct imaging observations for joint exoplanet detection and orbit estimation.” Astronomy & Astrophysics, 679, A38, 2023, https://arxiv.org/pdf/2309.08679
[2] Thiébaut+, “Beyond FRiM, ASAP: a family of sparse approximation for covariance matrices and preconditioners.” Adaptive Optics Systems VIII. Vol. 12185. SPIE, 2022, https://arxiv.org/pdf/2311.17721

Nature of the financial support for the internship: Labex LIO or team funding

Potential for a follow-up as a PhD thesis: Yes

Profil du candidat :
Background in signal processing, numerical methods or related fields.

Formation et compétences requises :

Adresse d’emploi :
Centre Astrophysique de Lyon
9 avenue Charles André
69230 Saint-Genis-Laval

Document attaché : 202411181114_FicheStage_CRAL_2024_AIRI_Flasseur-1.pdf

Offre en lien avec l’Action/le Réseau : – — –/– — –

Laboratoire/Entreprise : Laboratoire IBISC, Université d’Evry Paris-Saclay
Durée : 6 mois
Contact : Khalifa.Djemal@ibisc.univ-evry.fr
Date limite de publication : 2025-02-28

Contexte :

Sujet :
La détection de signes des pathologies d’Alzheimer qui est une maladie neurodégénérative est une tâche très importante dans un système d’aide au diagnostic médical. En effet, les techniques d’apprentissage automatique offrent aujourd’hui des perspectives pour détecter et identifier des troubles liés à la maladie, évaluer son avancement et à terme pouvoir rééduquer le patient. Dans un premier temps, le candidat fera une étude de l’état de l’art sur les troubles cognitives de la maladie et sur les techniques récentes employées pour reconnaitre la sévérité des patients. Il procèdera ensuite à la mise en place d’un modèle d’apprentissage à partir de bases de données qui permettra l’analyse de ces troubles cognitives conduisant ainsi à la classification et l’identification de la sévérité de la maladie.

[1] Hyun-Soo Choi, Jin Yeong Choe, HanjooKim, Ji Won Han, Yeon Kyung Chi, KayoungKim, Jongwoo Hong, Taehyun Kim, Tae Hui Kim, Sungroh Yoon and Ki Woong Kim. Deep learning based low-cost high-accuracy diagnostic framework for dementia using comprehensive neuropsychological assessment profiles, BMC Geriatrics, 18:234 (2018).

[2] Valeria Manera, Pierre-David Petit, Alexandre Derreumaux, Ivan Orvieto, Matteo Romagnoli, Graham Lyttle, Renaud David, and Philippe H. Robert, ’Kitchen and cooking’, a serious game for mild cognitive impairment and Alzheimer’s disease: a pilot study, Frontiers in Aging Neuroscience, 7: 24, 2015.

[3] Boaz Levy1, Samuel Gable, Elena Tsoy, Nurit Haspel, Brianna Wadler, Rand Wilcox, Courtney Hess, Jacqueline Hogan, Daniel Driscoll and Ardeshir Hashmi. Machine Learning Detection of Cognitive Impairment in Primary Care, Alzheimers Dis Dement, 1(2):38-46, 2017.

[4] Werner P, Rabinowitz S., Klinger E., Korczyn A. D., Josman N., Use of the virtual action planning supermarket for the diagnosis of mild cognitive impairment: a preliminary study, Dement Geriatr Cogn Disord, 27(4):301-9, 2009.

[5] Déborah A. Foloppe, Paul Richard, Takehiko Yamaguchi, Frédérique Etcharry-Bouyx & Philippe Allain, The potential of virtual reality-based training to enhance the functional autonomy of Alzheimer’s disease patients in cooking activities: A single case study, Neuropsychological Rehabilitation, October 2015.

[6] Khalifa Djemal and Hichem Maaref, Intelligent Information Description and Recognition in Biomedical Image Databases, In:Computational Modeling and Simulation of Intellect: Current State and Future Perspectives, Book Edited by Boris Igelnik, pages: 52-80, Publisher IGI Global, ISBN: 978-1-60960-551-3, February 2011.

[7] Florian Maronnat, Margaux Seguin, Khalifa Djemal, Cognitive tasks modelization and description in VR environment for Alzheimer’s disease state identification, in International conference on Image Processing Theory, Tools and Applications (IPTA 2020), November 09-12, 2020, Paris, France.

Profil du candidat :
Master 2 ou équivalent, de préférence des spécialités suivantes :
– Apprentissage automatique (Machine Learning),
– Imagerie Biomédicale
– Informatique Biomédicale,
– Informatique, Réalité Virtuelle et Systèmes Intelligents

Formation et compétences requises :

– Programmation Python, Matlab,
– Machine Learning
– Des connaissances de base en traitement d’images

Adresse d’emploi :
Laboratoire Informatique, Biologie Intégrative et Systèmes Complexes – IBISC 40 rue du Pelvoux, 91020 Evry, France

Document attaché : 202411151746_Sujet-stage-Master2-Djemal-2024-2025.pdf

Offre en lien avec l’Action/le Réseau : – — –/– — –

Laboratoire/Entreprise : CIRAD – UMR TETIS
Durée : 6 mois
Contact : roberto.interdonato@cirad.fr
Date limite de publication : 2025-02-28

Contexte :

Sujet :
Bonjour à tous,

Nous avons le plaisir de vous annoncer une offre de stage de 6 mois au laboratoire TETIS à Montpellier, axée sur le problème d’inférence de réseaux à partir des données hétérogènes epidémiologiques en utilisant des méthodes de Graph Neural Networks.

La date de début est prévue pour février 2025 (flexible). Vous trouverez la description détaillée de l’offre en français et en anglais ici :

https://nubes.teledetection.fr/s/mTiDsdxCPHbNid3

Pour toute question, n’hésitez pas à contacter Nejat Arınık (nejat.arinik@univ-artois.fr) ou moi-même (roberto.interdonato@cirad.fr).

Pour candidater, merci d’envoyer un mail à nejat.arinik@univ-artois.fr et roberto.interdonato@cirad.fr avec sujet “CANDIDATURE STAGE MOOD 2025” en ajoutant les éléments suivants:
– lettre de motivation expliquant vos qualifications, expériences et motivation pour ce sujet (1-2 pages)
— curriculum vitae (1-2 pages)
— relevé de notes de 1ère année de master et les notes de 2ème année de master disponibles ou équivalent pour les écoles
d’ingénieurs
— un lien vers des dépôts de projets personnels (par exemple GitHub ou GitLab)
— toute autre information que vous estimerez utile

N’hésitez pas à transmettre ces offres à des étudiants qui pourraient être intéressés.

Cordialement,

Roberto et Nejat
Roberto and Nejat

Profil du candidat :

Formation et compétences requises :

Adresse d’emploi :
500 rue Jean Francois Breton, Montpellier

Document attaché : 202411151304_Stage – Inférence de Réseaux à Partir des Données Hétérogènes.pdf

Offre en lien avec l’Action/le Réseau : – — –/– — –

Laboratoire/Entreprise : Equipe ORKAD / Laboratoire CRIStAL Lille
Durée : 6 mois
Contact : julie.jacques@univ-lille.fr
Date limite de publication : 2025-02-28

Contexte :
ORKAD est une équipe de recherche du groupe thématique OPTIMA du laboratoire CRIStAL (Centre de Recherche en Informatique, Signal et Automatique de Lille) (UMR CNRS 9189) de l’Université de Lille. L’objectif principal de l’équipe ORKAD est d’exploiter simultanément l’optimisation combinatoire et l’extraction de connaissances pour résoudre des problèmes d’optimisation. Les métaheuristiques ont souvent été utilisées avec succès pour résoudre différentes tâches de machine learning [DhaenensJourdan2022]. En particulier, l’algorithme MOCA-I [Jacques2013-a], permet de classifier des données hétérogènes et mal réparties par méthode d’optimisation, sur des données médicales [Jacques2020]. L’équipe ORKAD a des partenariats avec le CHU de Lille ; notamment dans le cadre du projet européen PATHACOV pour la détection du cancer du poumon à partir de la concentration en composés organiques volatils dans l’air expiré [Hulo2023]. Dans ce stage, nous nous intéressons à l’extension de ces travaux aux données du projet ALCOVE, suite du projet PATHACOV, où l’objectif est de distinguer différentes classes de sujets: sain / malade (avec le stade : I, II, III, IV) ; opérable / non opérable.

Sujet :
Dans le problème de classification multi-label, un enregistrement du jeu de données peut être associé à plusieurs labels : par exemple « cancer du poumon » et « opérable ». Des approches à base de métaheuristiques ont été proposées par le passé pour gérer ce problème, comme par exemple les colonies de fourmis [Otero2010]. La classification multi-label est souvent associée à une répartition déséquilibrée des différents labels à prédire [Tarekegn2021] et une des spécificités de l’algorithme MOCA-I est justement sa capacité à gérer ce déséquilibre [Jacques2013-a]. Dans MOCA-I, la modélisation est adaptée pour la classification binaire partielle (représentation de la solution, opérateurs d’initialisation et de voisinage,…). L’objectif de ce stage est de proposer une nouvelle représentation et opérateurs adaptés au problème de classification multi-label. Des méthodes de configuration automatique d’algorithmes comme irace [López-Ibáñez2016] seront utilisées pour identifier si les nouveaux opérateurs et stratégies proposés sont efficaces sur les benchmarks sélectionnés.

Profil du candidat :
Programmation Objet (Python ou C++) ; Connaissances en machine learning
Des connaissances en C++ et recherche opérationnelle, optimisation combinatoire seraient un plus.

Formation et compétences requises :
M2 en informatique

Adresse d’emploi :
Lieu : Laboratoire CRISTAL, Equipe ORKAD (Université de Lille, France)

Document attaché : 202411141558_Sujet_stage_M2.pdf

Offre en lien avec l’Action/le Réseau : – — –/– — –

Laboratoire/Entreprise : LIRIS
Durée : 6 mois
Contact : stefan.duffner@insa-lyon.fr
Date limite de publication : 2025-02-28

Contexte :

Sujet :
The first objective of this internship is to study and improve multi-modal Machine Learning models, for the fusion of video and EEG but potentially also EKG data, to predict the situations of our healthy control group. Based on our pre-liminary work on multi-modal LSTM and Transformer models, the aim would be to find characteristic patterns and correlations in the data that represent the different emotional or interactive situations, using eXplainable AI (XAI) techniques such as Integrated Gradient or SHAP.
The second objective would be to adapt these models and methods to DOC patients.

Profil du candidat :

Formation et compétences requises :

Adresse d’emploi :
INSA Lyon – LIRIS
7 Avenue Jean Capelle
69621 Villeurbanne

Document attaché : 202411111700_sujet_stage_M2_agoracoma_fusion1.pdf

Offre en lien avec l’Action/le Réseau : – — –/– — –

Laboratoire/Entreprise : Laboratoire Interdisciplinaire des Sciences du Num
Durée : 5 ou 6 mois
Contact : guinaudeau@limsi.fr
Date limite de publication : 2025-02-28

Contexte :
Most human interactions occur through spoken conversations. If this interaction mode seems so natural and easy for humans, it remains a challenge for spoken language processing models as conversational speech raises critical issues. First, non-verbal information can be essential to understand a message. For example a smiling face and a joyful voice can help detecting irony or humor in a message. Second, visual grounding between participants is often needed during a conversation to integrate posture and body gesture as well as references to the surrounding world. For example, a speaker can talk about an object on a table and refer to it as this object by designing it with her hand. Finally, semantic grounding between participants of a conversation to establish mutual knowledge is essential for communicating with each other.

Sujet :
In this context, the MINERAL project aims to train a multimodal conversation representation model for communicative acts and to study communicative structures of audiovisual conversation.
As part of this project, we are offering a 5- to 6-month internship focused on semi-automatic annotation of conversations in audio-visual documents. The intern’s first task will be to extend the existing annotation ontology for dialog acts, currently available for audio documents (through the Switchboard corpus for example), to incorporate the visual modality. In a second step, the intern will develop an automatic process for transferring annotations to new audiovisual datasets (such as meeting videos and TV series or movies) using transfer or few-shot learning approaches.

Practicalities:
The internship will be funded ~500 euros per month for a duration of 5 or 6 months and will take place at LISN within the LIPS team. This internship can potentially be followed by a funded PhD, based on performance and interest in continuing research in this area.

To apply, please send your CV, a cover letter and your M1 and M2 transcripts (if available) by email to Camille Guinaudeau camille.guinaudeau@universite-paris-saclay.fr and Sahar Ghannay sahar.ghannay@universite-paris-saclay.fr

Profil du candidat :

Formation et compétences requises :
Required Qualifications:
● Master’s degree (M2) in Computer Science or related field.
● Experience with deep learning frameworks such as Keras or PyTorch.
● Knowledge of image processing would be an advantage.

Adresse d’emploi :
LISN – Équipe LIPS
Campus Universitaire bâtiment 507
Rue du Belvédère
91400 Orsay

Document attaché : 202411111659_Stage_MINERAL.pdf