Portail des publications scientifiques IMT Mines Alès
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Eccentric cycling involves greater mental demand and cortical activation of the frontoparietal network
No full textInternational audienceEccentric, compared to concentric exercise, is proposed to involve different neuro-motor processing strategies and a higher level of mental demand. This study compared eccentric and concentric cycling at matched perceived effort and torque for the mental demand and related-cortical activation patterns. Nineteen men (30 ± 6 years) performed four different 5-min cycling conditions at 30 RPM on a semi-recumbent isokinetic cycle ergometer: (1) concentric at a moderate perceived effort (23 on the CR100® scale) without torque feedback; (2) concentric and (3) eccentric at the same average torque produced in the first condition; and (4) eccentric at the same moderate perceived effort than the first concentric condition. The conditions two to four were randomized. After each condition, mental demand was monitored using the NASA Task Load Index scale. Changes in oxy-(O 2 Hb) and deoxy-(HHb) hemoglobin during exercise were measured over both prefrontal cortices and the right parietal lobe from a 15-probe layout using a continuous-wave NIRS system. Mental demand was significantly higher during eccentric compared to concentric cycling (+52%, p = 0.012) and when the exercise intensity was fixed by the torque rather than the perceived effort (+70%, p < 0.001). For both torque-or perceived effort-matched exercises, O 2 Hb increased significantly (p < 0.001) in the left and right prefrontal cortices, and right parietal lobe, and HHb decreased in the left, and right, prefrontal cortices during eccentric compared to concentric cycling. This study supports that acute eccentric cycling, compared to concentric cycling, involves a higher mental demand, and frontoparietal network activation
Design and Evaluation of a Prototype Tactile Scanner for Active Sensing of Proximal Objects
No full textInternational audienceTactile interfaces, that can convey information to humans via tactile feedback, are still relatively rare. In this study we present a prototype ‘tactile scanner’, that fixes onto a user’s arm, and using arrays of capacitive sensors and vibratory motors, provides users with a sense of the proximity of objects near their arm. Through two experiments, we show that the device enables users to detect not just the position of objects, but also estimate their shapes and orientations. Finally, in a third experiment, we compare the user accuracy with the tactile scanner and their accuracy with real touch
Daily relationship satisfaction and markers of health: Findings from a smartphone‐based assessment
No full textInternational audienceRelationship satisfaction is associated consistently with better physical and mental health. Less is known about these associations in daily life, particularly the association between relationship satisfaction and cognitive health. This study examined the daily, within‐person association between relationship satisfaction and subjective health markers, including cognitive health. Participants from the United States ( N = 303; M age = 51.71, SD = 7.32) in the Couples Healthy Aging Project (CHAP) completed assessments of relationship satisfaction and health markers every night for eight days. Multilevel modeling was performed by accounting for personal (sex, age, race, education), relational (relationship duration), and contextual (day in the study, weekend day) factors. Within‐person, on days when participants were more satisfied with their relationship, they felt healthier, younger, more satisfied with their life, and more purposeful. They also reported a sharper mind, better memory, and clearer thinking; relationship satisfaction was unrelated to whether participants were bothered and disrupted by forgetting. Results indicated that a satisfying romantic relationship is closely associated with better physical, psychological, and cognitive health markers in daily life
Purpose in life and cognitive health: a 28-year prospective study
No full textInternational audienceObjectives : to examine the prospective association between purpose in life measured at three points across middle and older adulthood and cognitive outcomes assessed 8–28 years later.Design : prospective Study.Setting : Wisconsin Longitudinal Study of Aging (WLS).Participants : WLS participants who reported on their purpose in life at Round 4 (1992–1994; Mage = 52.58), Round 5 (2003–2007; Mage = 63.74), and/or Round 6 (2010–2012; Mage = 70.25) and were administered a cognitive battery at Round 7 (2020; Mage = 79.94) were included in the analysis (N = 4,632).Measurements : participants completed the Ryff measure of purpose in life and were administered the telephone interview for cognitive status and measures of verbal fluency, digit ordering, and numeric reasoning.Results : purpose in life measured at age 52 was related to better global cognitive function and verbal fluency but unrelated to dementia at age 80. In contrast, purpose in life at ages 63–70 was associated with lower likelihood of dementia, as well as better global cognitive function and verbal fluency at age 80. The effect sizes were modest (median Beta coefficient = .05; median odds ratio = .85). A slightly steeper decline in purpose in life between ages 52 and 70 was found for individuals with dementia at age 80.Conclusions : purpose in life is associated with healthier cognitive function measured up to 28 years later. Individuals with lower purpose, especially in their 60s or older, and with steeper declines in purpose, are more likely to have dementia at age 80
L’illusion de mouvement induite par stimulation vibratoire tendineuse : limitation liée au vieillissement
No full textInternational audienceIntroductionLes stimulations vibratoires tendineuses (SVT) excitent le fuseau neuromusculaire, responsables d’une illusion de mouvement (IM) et de l’activation des régions cérébrales sensorimotrices. Cependant, les mécanismes neurobiologiques impliqués sont imparfaitement connus. L’objectif de la présente étude était d’investiguer l’effet de l’âge et de l’ouverture/fermeture des yeux (YO/YF) sur l’IM. Nous avons supposé que les sujets jeunes et âgés ressentiraient plus fortement l’IM avec les YF et que ce ressenti serait plus important chez les jeunes.Méthode56 participants sains (jeunes : n=28 : 25,19 ± 5,89 ans ; âgés : n=28 : 63,64 ± 7,83 ans) ont été soumis à des SVT du triceps brachial droit ou gauche avec les YO (en regardant le membre vibré) ou avec les YF. En utilisant l’échelle de Beaulieu et al. (2020), les participants devaient reporter leur sensation de mouvement et la direction du mouvement, donnant un score total sur 4.RésultatsChez les participants jeunes et âgés, le score était significativement plus élevé avec les YF qu’avec les YO (jeunes : μ(YF/YO)=2,55/0,8, W=1346, p<0,001, d=1,64 ; âgés : μ(YF/YO)=1,22/0,57, W=546, p<0,001, d=0,57). De plus, le score avec les YF des participants jeunes était significativement plus élevé que celui des participants âgés (μ(jeunes/âgés)=2,55/1,22, U : 724, p<0,001, d=1,05).DiscussionL’IM était plus fortement ressentie avec les YF dans les deux groupes. Cette sensation était plus marquée chez les sujets jeunes que chez les sujets âgés. Ces variations physiologiques devront être prises en compte lors de l’utilisation d’une telle approche en pratique rééducative
Short-term interactions of concrete, biofilm, and seawater in the submerged zone of marine environments for sustainable floating offshore wind turbines
No full textVoir le pre-print : http://dx.doi.org/10.2139/ssrn.4919189International audienceThe durability of cover concrete in the submerged zone for floating offshore wind turbines is closely associated to the performance of the cement type used, which also plays a key role in the environmental impact of their construction and operation. A real-world study is conducted by simulating the concrete cover, submerging cementitious materials at a depth of 27 m in Banyuls-sur-Mer, located on the Mediterranean coast of France. The objective was to identify the short-term interactions between cementitious materials, biofilm developing at their surface, and seawater after 30- and 90 days exposure, with emphasis on, (i) the influence of cement type on the microbial composition of biofilm, and (ii) the influence of biofilm and seawater on the microstructural, chemical composition, and mineralogical changes within the cementitious matrix. After 30 days of exposure, scanning electron microscopy coupled to energy dispersive spectroscopy detected the formation of Mg-rich, S-rich, and Cl-rich zones in CEM I and CEM III concrete, while CEM V exhibited the same zonation after 90 days. These findings were corroborated by electron probe microanalysis. After 90 days of exposure, regardless of the cement type, calcium carbonate precipitated at the concrete-biofilm-seawater interface, predominantly in the form of aragonite crystals, as identified by X-ray diffraction analysis. In CEM I concrete, a brucite layer formed immediately beneath this CaCO3 deposit. The bacterial and eukaryotic diversity was identified using 16S rRNA and 18S rRNA sequencing, revealing diverse and dynamic communities over time. The macrofouling species, marine polychaetes (or serpulids), have been identified and considered to be biomineral in origin
La stimulation transcrânienne à courant direct anodique n’augmente pas les effets de l’entraînement par imagerie motrice sur une tâche de tapotement séquentiel des doigts chez de jeunes adultes
No full textInternational audienceWhen applied over the primary motor cortex (M1), anodal transcranial direct current stimulation (a-tDCS) could enhance the effects of a single motor imagery training (MIt) session on the learning of a sequential finger-tapping task (SFTT). This study aimed to investigate the effect of a-tDCS on the learning of an SFTT during multiple MIt sessions. Two groups of 16 healthy young adults participated in three consecutive MIt sessions over 3 days, followed by a retention test 1 week later. They received active or sham a-tDCS during a MIt session in which they mentally rehearsed an eight-item complex finger sequence with their left hand. Before and after each session, and during the retention test, they physically repeated the sequence as quickly and accurately as possible. Both groups (i) improved their performance during the first two sessions, showing online learning; (ii) stabilised the level they reached during all training sessions, reflecting offline consolidation; and (iii) maintained their performance level one week later, showing retention. However, no significant difference was found between the groups, regardless of the MSL stage. These results emphasise the importance of performing several MIt sessions to maximise performance gains, but they do not support the additional effects of a-tDCS.Lorsqu’elle est appliquée sur le cortex moteur primaire (M1), la stimulation transcrânienne à courant direct anodique (a-tDCS) pourrait potentialiser les effets d’une seule session d’entraînement par imagerie motrice (MIt) sur l’apprentissage d’une tâche séquentielle des doigts (TSD). Cette étude visait à examiner l’effet de l’a-tDCS sur l’apprentissage d’une TSD au cours de plusieurs sessions de MIt. Deux groupes de 16 jeunes adultes en bonne santé ont participé à trois sessions consécutives de MIt réparties sur 3 jours, suivies d’un test de rétention une semaine plus tard. Ils ont reçu une a-tDCS active ou fictive pendant une session de MIt au cours de laquelle ils ont mentalement répété une séquence complexe de huit mouvements des doigts avec la main gauche. Avant et après chaque session, ainsi que lors du test de rétention, ils ont physiquement reproduit la séquence aussi rapidement et précisément que possible. Les deux groupes ont : (i) amélioré leur performance au cours des deux premières sessions, montrant un apprentissage en ligne ; (ii) stabilisé le niveau atteint durant toutes les sessions, indiquant une consolidation hors ligne ; (iii) maintenu leur niveau de performance une semaine plus tard, démontrant une rétention. Cependant, aucune différence significative n’a été observée entre les groupes, quel que soit le stade de l’apprentissage moteur. Ces résultats soulignent l’importance de réaliser plusieurs sessions d’imagerie motrice pour maximiser les gains de performance, mais ne soutiennent pas l’effet additif de l’a-tDCS
Étude du radiogreffage de matériaux lignocellulosiques
No full textDue to the growing interest in sustainable and environmentally friendly materials, the use oflignocellulosic resources is significantly increasing. However, certain inherent drawbacks of thesematerials limit their application in various fields. Several strategies can be considered to addressthese issues and optimize their performances. Among them, radiation-induced grafting, firstdeveloped in the mid-1950s, presents interesting features. This technique involves exposing amaterial to ionizing radiations to graft functional monomers onto it, thereby imparting newproperties. Several radiation-induced grafting methods exist, including irradiating the materialbefore introducing the monomers (pre-irradiation grafting) or irradiating it simultaneously withthem (simultaneous irradiation grafting). Despite the general rules governing the feasibility of thesemethods, the operating conditions for each substrate must be adapted to establish the mosteffective process. This work aims to explore the potential for radiation-induced grafting applied toMiscanthus × giganteus stem fragments, as well as flax in the form of short and long fibers (fabrics). A detailed study of the operating conditions and characteristics of the treated materials enabled the determination of the most appropriate methodology to achieve the desired results. As a result, lignocellulosic materials with flame-retardant or hydrophobic properties were successfullyprepared. Finally, this work proposed an innovative radiation-induced grafting method thatcombines several existing methodologies.En raison de l'intérêt croissant pour des matériaux durables et respectueux de l'environnement,l'utilisation des ressources lignocellulosiques connaît une augmentation significative. Toutefois,certains inconvénients inhérents à ces matériaux limitent leur application dans divers domaines.Plusieurs stratégies sont envisageables afin d’y remédier et optimiser leurs performances. Parmielles, le radiogreffage, dont les premiers développements datent du milieu des années 1950,présente des caractéristiques intéressantes. Cette technique consiste à exposer un matériau à desrayonnements ionisants afin d'y greffer des monomères fonctionnels, lui conférant ainsi denouvelles propriétés. Plusieurs méthodes de radiogreffage existent, notamment, il est possibled’irradier le matériau avant de la mise en contact avec les monomères (pré-irradiation), ou bien del’irradier en leur présence (irradiation simultanée). Malgré des règles générales qui conditionnent la faisabilité de ces méthodes, pour chaque cas, les conditions opératoires sont à adapter pour mettre en place le procédé le plus efficace possible. Cette thèse a pour objectif d’étudier les possibilités de fonctionnalisation par radiogreffage des fragments de tiges de Miscanthus × giganteus ainsi que du lin sous forme de fibres courtes et longues (tissus). L'étude approfondie des conditions opératoires et des caractéristiques des matériaux traités a permis de déterminer la méthodologie la plus appropriée pour atteindre les résultats désirés. Ainsi, des matériaux lignocellulosiques dotés de propriétés ignifuges ou hydrophobes ont été préparés avec succès. Enfin, ce travail a permis de proposer une nouvelle méthode originale de radiogreffage, qui repose sur une combinaison de plusieurs méthodologies existantes
GUing: A Mobile GUI Search Engine using a Vision-Language Model
No full textInternational audienceGraphical User Interfaces (GUIs) are central to app development projects. App developers may use the GUIs of other apps as a means of requirements refinement and rapid prototyping or as a source of inspiration for designing and improving their own apps. Recent research has thus suggested retrieving relevant GUI designs that match a certain text query from screenshot datasets acquired through crowdsourced or automated exploration of GUIs. However, such text-to-GUI retrieval approaches only leverage the textual information of the GUI elements, neglecting visual information such as icons or background images. In addition, retrieved screenshots are not steered by app developers and lack app features that require particular input data. To overcome these limitations, this paper proposes GUing, a GUI search engine based on a vision-language model called GUIClip, which we trained specifically for the problem of designing app GUIs. For this, we first collected from Google Play app introduction images which display the most representative screenshots and are often captioned (i.e. labelled) by app vendors. Then, we developed an automated pipeline to classify, crop, and extract the captions from these images. This resulted in a large dataset which we share with this paper: including 303k app screenshots, out of which 135k have captions. We used this dataset to train a novel vision-language model, which is, to the best of our knowledge, the first of its kind for GUI retrieval. We evaluated our approach on various datasets from related work and in a manual experiment. The results demonstrate that our model outperforms previous approaches in text-to-GUI retrieval achieving a Recall@10 of up to 0.69 and a HIT@10 of 0.91. We also explored the performance of GUIClip for other GUI tasks including GUI classification and sketch-to-GUI retrieval with encouraging results
Mécanisme d’attention pour le sous-titrage du mouvement humain : Vers une segmentation sémantique et analyse du mouvement interprétables
No full textCaptioning tasks mainly focus on images or videos, and seldom on human poses. Yet, poses concisely describe human activities. Beyond text generation quality, we consider the motion caption task as an intermediate step to solve other derived tasks. In this holistic approach, our experiments are centered on the unsupervised learning of semantic motion segmentation and interpretability. We first conduct an extensive literature review of recent methods for human pose estimation, as a central prerequisite for pose-based captioning. Then, we take an interest in pose-representation learning, with an emphasis on the use of spatiotemporal graph-based learning, which we apply and evaluate on a real-world application (protective behavior detection). As a result, we win the AffectMove challenge. Next, we delve into the core of our contributions in motion captioning, where: (i) We design local recurrent attention for synchronous text generation with motion. Each motion and its caption are decomposed into primitives and corresponding sub-captions. We also propose specific metrics to evaluate the synchronous mapping between motion and language segments. (ii) We initiate the construction of a motion-language dataset to enable supervised segmentation. (iii) We design an interpretable architecture with a transparent reasoning process through spatiotemporal attention, showing state-of-the-art results on the two reference datasets, KIT-ML and HumanML3D. Effective tools are proposed for interpretability evaluation and illustration. Finally, we conduct a thorough analysis of potential applications: unsupervised action segmentation, sign language translation, and impact in other scenarios.Dans l’état de l’art, les tâches de sous-titrage se concentrent souvent sur les images et les vidéos, mais rarement sur les poses humaines. Ces dernières offrent pourtant une représentation concise des activités humaines et, au-delà de la qualité de la génération de texte, la tâche de "légendage" de mouvement peut constituer un intermédiaire pour résoudre d’autres tâches dérivées. Les travaux présentés dans ce manuscrit sont centrés sur l’apprentissage non supervisé qui peut être utilisé pour la segmentation de mouvement et l’identification d’une sémantique associée, ainsi que son interprétabilité. Après une revue de la littérature des méthodes récentes pour l’estimation de poses humaines, un prérequis central pour le légendage basé sur la pose, nous nous intéressons à l’apprentissage de la représentation de pose, avec un accent sur la modélisation basée sur des graphes spatio-temporels. Notre modèle est évalué sur une application réelle de détection de comportement protecteur, pour laquelle nous avons gagné le défi AffectMove. Les contributions majeures concernant le légendage du mouvement sont ensuite détaillées en trois temps. (i) Un mécanisme d’attention récurrent local pour la génération de texte synchronisé avec le mouvement est proposé, où chaque mouvement et sa légende sont décomposés en primitives et sous-légendes correspondantes. Des métriques spécifiques sont proposées pour évaluer la correspondance entre les segments de mouvement et les segments de langage. (ii) Un jeu de données mouvement-langage est ensuite proposé pour permettre une segmentation supervisée. (iii) Enfin, une architecture interprétable avec un processus de raisonnement transparent à travers l’attention spatio-temporelle est proposée. Cette architecture montre des "résultats état-de-l’art" sur les deux jeux de données de référence, KITML et HumanML3D. Des outils efficaces sont proposés pour l’évaluation et l’illustration de l’interprétabilité. Ces contributions ouvrent de nombreuses perspectives de recherche et le manuscrit se termine par une analyse approfondie des applications potentielles : la segmentation d’actions non supervisée, la traduction automatique de la langue des signes ou encore l’impact dans d’autres scénarios