Portail des publications scientifiques IMT Mines Alès
Not a member yet
5198 research outputs found
Sort by
Interbrain synchrony trajectories during teamwork: an fNIRS hyperscanning study
No full textInternational audiencePsychological theories suppose that teamwork evolves over a task episode, but this hypothesis cannot be tested using questionnaires. This study used fNIRS hyperscanning methods to assess teamwork by examining the temporal course of interbrain synchrony (IBS) in the prefrontal cortex and temporoparietal junction over a 30-minute task in 40 dyads
Non destructive qualification of bovine meat tenderness
No full textInternational audienceTenderness is one of the most important criteria in bovine meat, as it determines whether the meat is used for grilling, long-time cooking or post-processing. It is therefore of great interest for the industry to measure it. Common systems require the extraction and destruction of samples, inducing time and material expenses. In this article, a new nondestructive characterization apparatus, based on monitored indentation, relaxation, and recovery, is proposed. Samples from two cuts known for their difference in tenderness were used from the same carcass. Their tenderness were assessed via compression tests and then compared to indicators from the force-displacement measurements. Results showed that the indentation and recovery speed, and the force relaxation enable the differentiation of the two cuts (p<0.05). These results were obtained on samples from a single carcass. Measurements on other carcasses should be performed to ensure that the results presented in this article can be generalized to bovine meat
Hygrothermal Performance Investigation of Building Limestones in Variable Climate
No full textInternational audienceDue to the new challenges imposed by sustainable development, the construction industry is having to rethink its activities. The use of natural stone makes it possible, among other things, to respond to environmental challenges facing the building sector. In addition to its good thermo-hydric properties, the potential of natural stone lies in its production which requires less energy than materials such as concrete, and its durability over time which reduces the need for deconstruction and reconstruction, thus excluding the carbon impact associated with these activities. To promote this natural and environmentally friendly material, it is vital to know its multiphysical characteristics. This research work consisted of studying the thermal and hydric properties of local limestone. The data were then used to numerically simulate the hygrothermal coupling behaviour of this material in an environment of variable humidity and temperature. The simulation results are compared with experimental measurements obtained from limestone blocks exposed to variable climatic conditions. The results show that the limestones studied are sensitive to capillarity and are permeable to water vapour, thereby improving indoor air quality and limiting the risk of condensation and mould growth inside the walls. The numerical model accurately predicted the thermal response of the materials studied
Development and psychometric properties of the Balance in Daily Life (BDL) scale in a population of frail older people
No full textInternational audienceBackground: Balance disorders in older people cause falls, which can have serious functional and economicconsequences. No existing scale relates fall risk to daily life situations. This study describes the development,psychometric properties and construct validity of the Balance in Daily Life (BDL) scale, comprising seven routinetasks including answering a phone, carrying a heavy bag, and sitting down and getting up from a chair.Methods: Frail patients aged 65 years or more were prospectively recruited from the geriatric rehabilitationdepartment of a French university hospital. Inclusion criteria included autonomous walking over 20 m andmodified Short Emergency Geriatric Assessment score 8–11. Patients with motor skills disorders and compre-hension or major memory difficulties were excluded. Patients were assessed on Day 3 and Day 30 with theBalance in Daily Life scale, Timed Up and Go, one-leg stance time, sternal nudge and walking-while-talking tests.The scale was assessed for acceptability, quality, unidimensionality, internal consistency, reliability, temporalstability, responsiveness and construct validity.Results: 140 patients (83 ± 6 years) were recruited, of whom 139 were assessed at Day 0 and 133 at Day 30.Acceptability was satisfactory (134/139 patients completed the test), quality assessment showed a slight flooreffect (6 % of patients with minimal score) and evaluation of item redundancy found no strong correlation(Spearman <0.7). Unidimensionality was verified (Loevinger H coefficient > 0.5 for all items except item 6 =0.4728). Internal consistency was good (Cronbach alpha = 0.86). Reliability and temporal stability wereexcellent (ICC = 0.97 and ICC = 0.92). Responsiveness was verified by significant score change p < 0.0001between Day 0 and Day 30 (decreased by 1 [0; 2] point), in line with other score changes. Construct validityrevealed that the Balance in Daily Life scale was convergent with results of the timed up-and-go and one-legstance time (p < 0.0001 for both) and tended to be higher for participants who had not fallen in the previous6 months (p = 0.0528). The new questionnaire was divergent to sternal nudge tests (p = 0.0002) and not relatedto the walking-while-talking test (p = 0.5969).Conclusion: The Balance in Daily Life scale has good psychometric properties for this population. Its simplicityand innovative nature mean that it can be applied in institutions while being easily modifiable to domesticsettings.Study registration on clinicaltrials.gov: NCT033438
Le phénomène du feu couvant dans les bétons biosourcés - Thèse BIOFEU (2023-2026)
No full textInternational audienc
Guided Attention for Interpretable Motion Captioning
No full textInternational audienceDiverse and extensive work has recently been conducted on text-conditioned human motion generation. However, progress in the reverse direction, motion captioning, has seen less comparable advancement. In this paper, we introduce a novel architecture design that enhances text generation quality by emphasizing interpretability through spatio-temporal and adaptive attention mechanisms. To encourage human-like reasoning, we propose methods for guiding attention during training, emphasizing relevant skeleton areas over time and distinguishing motion-related words. We discuss and quantify our model's interpretability using relevant histograms and density distributions. Furthermore, we leverage interpretability to derive fine-grained information about human motion, including action localization, body part identification, and the distinction of motion-related words. Finally, we discuss the transferability of our approaches to other tasks. Our experiments demonstrate that attention guidance leads to interpretable captioning while enhancing performance compared to higher parameter-count, non-interpretable state-of-the-art systems. The code is available at: https://github.com/rd20karim/M2T-Interpretable
Extreme Poisson’s ratios recorded in the secondary phloem of Malvaceae: a highlight on the biomechanical function of bark
No full textInternational audienceIn some angiosperm species, especially in the Malvaceae family, postural control and directional growth of the stem areenabled by the mechanical interaction between the growing cambium and the secondary phloem. A key feature of this motormechanism is the ability to redirect the tangential stress induced in secondary phloem into a longitudinal stress enabling thecontrol of stem orientation. Here we studied how the microstructure of the secondary phloem is optimized for this function.We measured the longitudinal-tangential Poisson’s ratio and the longitudinal modulus of elasticity of secondary phloem in 22tree species including Malvaceae and other families. We modeled the microstructure of Malvaceae secondary phloem usingfinite elements. The Poisson’s ratio of secondary phloem from Malvaceae trees was found one to two orders of magnitudehigher than for other species, reaching the highest values ever reported for a natural material. Mechanical modeling confirmedthese results and showed that parameters of the microstructure of secondary phloem are set at value optimizing this Poisson’sratio. This highlights that the specific microstructure of Malvaceae secondary phloem is designed to maximize the conversionof cambial growth pressure into a longitudinal mechanical stress enabling the directional growth
Enhancing Insight into Photochemical Weathering of Flax and Miscanthus: Exploring Diverse Chemical Compositions and Composite Materials
No full textInternational audienceThe accelerated weathering of flax and miscanthus fibers possessing distinct chemicalcompositions was investigated. The chosen fibers included raw, extractive-free (EF) and delignifiedsamples (x3), alone and used as fillers in a stabilized polypropylene blue matrix (PP). Modificationsin both color and the chemical composition of the fibers throughout the weathering process underultraviolet (UV) light were meticulously tracked and analyzed by spectrophotometry and attenuatedtotal reflectance with Fourier-transform infrared spectroscopy (ATR-FTIR). The inherent natureand composition of the selected fibers led to varied color-change tendencies. Raw and EF flaxfibers exhibited lightening effects, while raw and EF miscanthus fibers demonstrated darkeningeffects. Extractives exhibited negligible influence on the color alteration of both flax and miscanthusfibers. This disparity between the fibers correlates with their respective lignin content and type, andthe significant formation of carbonyl (C=O) groups in miscanthus. Better stability was noted fordelignified flax fibers. A comparative study was achieved by weathering the PP matrix containingthese various fibers. Contrary to the weathering observations on individual fibers, it was noted thatcomposites containing raw and EF flax fibers exhibited significant color degradation. The other fibercontaining formulations showed enhanced color stability when compared to the pure PP matrix. Thestudy highlights that the UV stability of composites depends on their thermal history. As confirmedby thermogravimetric analysis (TGA), fiber degradation during extrusion may affect UV stability, afactor that is not apparent when fibers alone are subjected to UV aging
Preprocessing of Iris Images for BSIF-Based Biometric Systems: Binary Detected Edges and Iris Unwrapping
No full textInternational audienceThis work presents a novel approach to enhancing iris recognition systems through a two-module approach focusing on low-level image preprocessing techniques and advanced feature extraction. The primary contributions of this paper include: (i) the development of a robust preprocessing module utilizing the Canny algorithm for edge detection and the circle-based Hough transform for precise iris extraction, and (ii) the implementation of Binary Statistical Image Features (BSIF) with domain-specific filters trained on iris-specific data for improved biometric identification. By combining these advanced image preprocessing techniques, the proposed method addresses key challenges in iris recognition, such as occlusions, varying pigmentation, and textural diversity. Experimental results on the Human-inspired Domain-specific Binarized Image Features (HDBIF) Dataset, consisting of 1892 iris images, confirm the significant enhancements achieved. Moreover, this paper offers a comprehensive and reproducible research framework by providing source codes and access to the testing database through the Notre Dame University dataset website, thereby facilitating further application and study. Future research will focus on exploring adaptive algorithms and integrating machine learning techniques to improve performance across diverse and unpredictable real-world scenarios
Weekly Programming of Hamstring-Related Training Contents in European Professional Soccer
No full textInternational audienceHamstring injuries in soccer continue to be a challenge for professionals who work with soccer players daily. Although its origin is multifactorial, the proper management of neuromuscular fatigue during the training microcycle is a very important factor to consider. There are no clear guidelines regarding the weekly distribution of certain exercises that demand the hamstrings. The main objective of this study was to describe the usual training practices of professional European soccer teams. An international observational survey design was applied to some of the strength and conditioning coaches of professional soccer teams. The survey included different neuromuscular demanding exercises for the hamstrings. For each exercise, the strength and conditioning coaches had to respond in relation to their frequency of use and timepoint depending on the day of the weekly microcycle. Although there is no strong consensus in this regard, there does seem to be a trend when applying certain exercises, especially on the days matchday-4 and matchday-3