HAL Université de Toulouse, et Toulouse INP
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LUNTIAN: An Agent-Based Model of an Industrial Tree Plantation for Promoting Sustainable Harvesting in the Philippines
No full textInternational audienceIndustrial tree plantations (ITPs) are increasingly recognized as a sustainable response to deforestation and the decline in native wood resources in the Philippines. This study presents LUNTIAN (Labor, UNiversity, Timber Investment, and Agent-based Nexus), an agent-based model that simulates an experimental ITP operation within a mountain forest managed by University of the Philippines Los Baños. The model integrates biophysical processes—such as tree growth, hydrology, and stand dynamics—with socio-economic components such as investment decision making based on risk preferences, employment allocation influenced by local labor availability, and informal harvesting behavior driven by job scarcity. These are complemented by institutional enforcement mechanisms such as forest patrolling, reflecting the complex interplay between financial incentives and rule compliance. To assess the model’s validity, its outputs were compared to those of the 3PG forest growth model, with results demonstrating alignment in growth trends and spatial distributions, thereby supporting LUNTIAN’s potential to represent key ecological dynamics. Sensitivity analysis identified investor earnings share and community member count as significant factors influencing net earnings and management costs. Parameter calibration using the Non-dominated Sorting Genetic Algorithm yielded an optimal configuration that ensured profitability for resource managers, investors, and community-hired laborers while minimizing unauthorized independent harvesting. Notably, even with continuous harvesting during a 17-year rotation, the final tree population increased by 55%. These findings illustrate the potential of LUNTIAN to support the exploration of sustainable ITP management strategies in the Philippines by offering a robust framework for analyzing complex social–ecological interactions
Memguard-RW: Improved Real-Time Memory Bandwidth Regulation Within a Hypervisor
No full textInternational audienceMemory bandwidth is a critical factor in the performance of DRAM-based computing architectures, particularly in memory-intensive computations. Modern multi-core processors share critical resources, such as main memory and cache, which impact the predictability of real-time systems due to resource contention. Techniques like memory access regulation, cache partitioning, and static hypervisors aim to mitigate this contention.This paper presents an improvement of a memory control mechanism based on MemGuard, named MemGuard-RW, designed and implemented within a hypervisor. MemGuard-RW uses two performance counters for measuring the memory accesses, one for memory readings and another one for writings, thus decreasing the pessimism on the original memory access budget from MemGuard. Additionally, we extend the MemGuard schedulability analysis considering the two-counter approach. To evaluate the effectiveness of the implementation and analysis, we deployed FreeRTOS as a guest alongside three stress-generating guests, measuring the interference experienced by the FreeRTOS instance and comparing the analysis with two counters with the original analysis with one counter, using modern benchmarks. The results demonstrate that the proposed mechanism successfully regulates memory accesses, showing its potential for enhancing the predictability and performance of real-time systems in multi-core environments. Our proposed analysis with two counters reduces the upper bound of around 20% for tasks having medium and high memory usage
Intégration d'un modèle de propulsion hybride électrique dans un modèle d'aéronef complet, incluant aérodynamique et structure, en vue de sa conception multidisciplinaire
No full textInternational audienceCet article se focalise sur la conception multidisciplinaire d’un avion régional hybride série. L’étude fait suite au projet européen HASTECS coordonné par le LAPLACE, qui visait à concevoir la chaîne de propulsion hybride électrique. Le travail réalisé a été repris et enrichi dans notre étude en incluant le couplage aux caractéristiques aérodynamiques et de structure de l’avion, sur la base de modèles système avion complémentaires développés par l’ONERA. La nouvelle formulation proposée pour la conception multidisciplinaire de l’avion par optimisation conduit à une meilleure prise en compte des différents couplages et permet d’intégrer de nouveaux degrés de liberté exploitables dans une optimisation «système» multidisciplinaire dite «MDO» (forme de la mission de vol, conception de l’aile, topologie de l’avion, etc.
Caractérisation fonctionnelle et moléculaire de l'hétérogénéité de réponses musculaires à l'exercice avec l'âge
No full textWorld Health Organisation recommends to practice physical activity as its many beneficial effects on physical and mental health are widely acknowledged by the scientific and medical community. Active ageing is characterized by a lower risk of age-related diseases, a better quality of life, and therefore a longer healthspan than sedentary people. Indeed, physical activity improves a number of functions impaired by ageing, such as cognition and locomotion, and therefore appears to be an ideal solution for reducing the negative effects of ageing, at both an individual and societal level. However, the changes vary greatly from person to person. This heterogeneity can be seen, for example, in the evolution of function and muscle mass within a group that exercised regularly. People can be categorized according to their progress: low (or non-responders), moderate or high responders to exercise. It is suggested that the proportion of low responders increases with age, which has implications for the universal scope of exercise as a preventative measure against ageing. As part of my PhD, we are replicating this phenomenon in aged mice to investigate the cellular and molecular mechanisms responsible for the low muscle response, which is organized around 2 axes: 1) reproduce the heterogeneity of muscle progression after exercise in mice, and identify mice with low muscle response, 2) determine the cellular and molecular mechanisms altered in low versus high responders. As a first step, we established the first protocol to observe and analyse response heterogeneity in a mouse model. After eight weeks of training with a weighted wheel, we observed heterogeneity in several muscle function tests (strength, endurance, etc.). As the responses were not always correlated, we analysed these data using several tools, allowing us to carry out the first study comparing different methods on the same cohort, with the aim of classifying mice as responders or non-responders. In this way, we have highlighted the fact that the methods used in the literature do not have the same sensitivity, and that it is difficult to compare them. Another conclusion is the absence of global non-responders, i.e. mice do not respond to all functional tests. Finally, there is always a benefit to exercise, even if not all the expected benefits. Secondly, we classified the mice according to their strength progress after training (grip test). A transcriptomic analysis of muscles from high- and low-responders showed no difference in the expression of our genes of interest, at rest. We performed a single-nuclei RNA-seq of muscles from low- and high-responders, on muscle dissected six hours after an acute exercise. The transcriptomic response to this challenge stimulates oxidative genes significantly more in low-responders, which looks like untrained mice's responses. Moreover, protein analyses suggest an imbalance in protein homeostasis in low-responders, with lower synthesis and higher degradation. We have therefore developed a mouse model that allows us to study the phenomenon of heterogeneous muscle response to exercise, on a physiological scale. Observations made in low-responder mice provide an avenue for intervention. We aim to target specific identified mechanisms in order to reduce the proportion of low-responders in a cohort of aged mice.La pratique régulière d'une activité physique est recommandée par l'OMS, ses multiples effets bénéfiques sur l'état de santé physique et mentale faisant consensus au sein de la communauté scientifique et médicale. Le vieillissement de personnes actives est caractérisé par un moindre risque de maladies liées à l'âge, une meilleure qualité de vie et donc une espérance de vie en bonne santé plus longue par rapport à des personnes sédentaires. En effet, l'activité physique améliore plusieurs fonctions altérées lors du vieillissement, notamment la cognition et la locomotion, et semble donc être une solution idéale pour diminuer les effets négatifs du vieillissement, à l'échelle individuelle et sociétale. Toutefois, les changements induits par l'exercice sont très variables en fonction des personnes. Cette hétérogénéité se voit, par exemple, dans l'évolution des fonctions et de la masse musculaire au sein d'un groupe ayant pratiqué un exercice physique régulier. On peut catégoriser les personnes en fonction de leur progression : faibles (ou non-répondeurs), modestes ou forts répondeurs à l'exercice. Il semblerait que la proportion de faibles répondeurs augmente avec l'âge, ce qui affecte donc la portée universelle de l'exercice comme prévention du vieillissement. Dans le cadre de mon doctorat, nous reproduisons ce phénomène chez la souris âgée pour explorer les mécanismes cellulaires et moléculaires responsables de la faible réponse musculaire, ce qui s'organise en 2 axes : 1) reproduire l'hétérogénéité de progression musculaire suite à un exercice chez la souris et identifier les souris à faible réponse musculaire, 2) déterminer les mécanismes cellulaires et moléculaires altérés chez les faibles répondeurs par rapport aux forts répondeurs. Dans un premier temps nous avons mis au point le premier protocole permettant d'observer et d'analyser l'hétérogénéité de réponses dans un modèle murin. Suite à huit semaines d'entraînement avec une roue lestée, nous avons observé une hétérogénéité d'évolution dans plusieurs tests de fonction musculaire (force, endurance). Les réponses n'étant pas toujours corrélées, nous avons analysé ces données à l'aide de plusieurs outils, ce qui nous a permis de réaliser la première étude comparant différentes méthodes sur une même cohorte, dans le but de classer les souris en répondeurs ou non-répondeurs. Ainsi, nous avons mis en évidence le fait que les méthodes utilisées dans la littérature n'ont pas la même sensibilité, et qu'il est difficile les comparer entre elles. Une autre conclusion que nous apportons est l'absence de non-répondeurs globaux. Dans un deuxième temps, nous avons classé les souris en fonction de leur évolution de force suite à l'entraînement (grip-test). La comparaison des muscles des souris à faibles et à fortes réponses musculaire ne montre pas de différence dans l'expression des gènes ciblés par nos analyses, au repos. Nous avons réalisé un single-nuclei RNA-seq des muscles de souris à faibles et à fortes réponses suite à un exercice aigu. La réponse transcriptomique à ce challenge mobilise les gènes du métabolisme oxydatif plus importante dans les muscles des souris à faible réponse à l'entraînement, de manière similaire à des souris non entrainées. Les analyses protéiques suggèrent un déséquilibre dans l'homéostasie protéique dans les muscles de souris à faible réponse, avec une moins bonne synthèse et une dégradation plus importante. Ainsi, nous avons développé un modèle murin qui permet d'étudier le phénomène d'hétérogénéité de réponses musculaire à l'exercice, à l'échelle physiologique. Les observations réalisées sur les souris à faibles réponses sont une piste pour des interventions. Nous souhaitons tester de cibler certains mécanismes identifiés dans le but de diminuer la proportion de faibles répondeurs dans une cohorte de souris âgées
Strike-slip tectonic-driven peraluminous rare-metal magmatism: insights from the late-Variscan Blond granitic complex (French Massif Central)
No full textInternational audienceDuring the late Carboniferous to early Permian, major crustal magmatism in the internal domains of the European Variscan belt was locally associated with the emplacement of small volume of highly-fractionated peraluminous magmas strongly enriched in rare metals such as Li, Be, Nb, Ta, Sn, and W known as rare-metal granites and pegmatites. The northern part of the French Massif Central (FMC) is particularly well endowed with such deposits, and significant scientific research has focused on their formation conditions and magmatichydrothermal evolution. However, the tectonic context of rare-metal magmas emplacement, including the role of deformation in melt extraction, ascent and metal enrichment, remains poorly understood. The Blond peraluminous granitic complex, located in the NW FMC, represents an ideal natural laboratory for studying the relationship between late-Variscan tectonics and rare-metal magmatism. The main granitic intrusion consisting of two-mica and muscovite facies was syntectonically emplaced at 319 ± 7 Ma along the Oradour fault, a major late-Variscan N135-striking dextral strike-slip shear zone. Both facies are crosscut by several F-Sn-(Li)-rich topaz-cassiterite granitic dykes and stocks (”ongonite”) likely emplaced in relation to N60-striking sinistral shear zones. New structural measurements, petro-geochemical analyses, and U-Pb dating are currently in progress to investigate the magmatic and tectonic history of the Blond complex and its relationship with the emplacementof strongly evolved melts.In the northwest part of the complex (La Puelle quarry), the muscovite facies of the Blond granite shows a ~N100 oriented subvertical magmatic fabric and is affected by two sets of high-dipped strike-slip shear bands (mean: N033-77°E and N072-82°S) and one set of steep ongonite dykes (mean: N006-62°E). The shear bands are sinuous and show sinistral plastic to brittle-plastic deformation as protomylonitic zones with S-C fabrics and cores of (ultra)mylonite or ultracataclasite. They bear sub-horizontal lineations or striations, and are locally overprinted by extensional fractures developed along the shear band and filled by combquartz. The ongonite dykes (1 to 20-cm thick) are commonly sinuous, locally arranged in en échelon pattern, and become thinner in the propagation tip. The contacts between the dykes and the host rock are either sinuous or sharp. One ongonite dyke is plastically deformed within a sinistral shear zone, which supports a syntectonic emplacement. The reduced stress tensor calculated through inversion of structures (n=34) is consistent with reverse strike-slip deformation (sub-vertical ) with a sub-horizontal N010-oriented σ1. The structures in the quarry can be explained with the classical Riedel shear model, where the ongonite dykes represent tension gashes, and the N033 and N072-oriented families the R’ and P’ antithetic shear zones, respectively, linked at depth to the Oradour fault. In situ U-Pb dating of magmatic cassiterite constrains the emplacement of ongonites at 310 ± 6 Ma. The episode of tectonically-assisted rare-metal magmatism seems synchronous with the N-S-striking emplacement of the Richemont rare-metal rhyolitic dyke (313 ± 3 Ma) and wolframite-cassiterite-bearing quartz veins (310 ± 4 Ma). These observations underscore the significant role of late-Variscan strike-slip tectonics in creating structures of localized extension, which facilitated the vertical migration of rare-metal-rich melts and the focalization of mineralizing fluids at upper crustal levels.This work is funded by ANR-22-EXSS-0014
Increasing the throughput of Direct-to-Satellite Narrowband IoT networks
No full textInternational audienceThe design of a Direct-to-Satellite (DtS) network infrastructure based on the availability of Low Earth Orbit (LEO) satellite constellations has recently emerged as a key enabler of global Internet of Things (IoT) connectivity. In this context, Narrowband IoT (NB-IoT) communications can be leveraged as a standards-based DtS solution that can grant reliable data collection in areas not reachable by traditional terrestrial IoT networks. However, the large coverage area of satellites and the limited connection time increase the probability of collisions during the NB-IoT Random Access (RA) procedure. This is especially true when many concurrent User Equipments (UEs) attempt to access the network simultaneously during the RA procedure. In this sense, the goal of this contribution is to show that the first message exchange between UEs and NB-IoT equipped LEO satellites (i.e., an uplink Msg1 frame followed by a downlink Msg2 frame) can be exploited by UEs to decide whether to try transmitting data into an uplink Msg3 frame or not. Herein, 2 early collision detection methods able to improve the RA success rate in satellite NB-IoT systems are presented. In detail, for both methods UEs estimate their relative position to the satellite and apply a corresponding time shift when transmitting Msg1. By comparing the Time Advance (TA) value received in Msg2 with their expected TA, UEs can determine whether to proceed with Msg3. The Closest First Method (CFM) requires no changes to the satellite and only uses the TA value of the first received Msg1. Instead, the Non-collided First Method (NFM) assumes the satellite can identify individual Msg1 transmissions and responds only to non-collided ones. Some preliminary simulation results show that both methods increase the number of successful accesses compared to the standard approach, even in the presence of position estimation errors
Design tools for 2- and multi level converters and transformerless partial power converters.: Invited talk for internal seminar
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Real-time gait event detection using motion capture to control an electrical stimulator: Proof-of-concept
No full textInternational audienceCerebral palsy (CP) is the most prevalent motor disorder in childhood and often results in gait abnormalities that hinder mobility and diminish quality of life. Functional electrical stimulation (FES) has demonstrated potential in enhancing gait in individuals in this population, however, its practical implementation remains complex, as it requires monitoring various gait parameters and delivering personalized stimulation to different muscles in order to correct various gait impairments. Recent advancements in real-time motion capture (MOCAP) and wearable sensors now enable the development of closed-loop, multi-channel FES systems. This study will assess the feasibility and responsiveness of a real-time, event-triggered multi-channel stimulation protocol during treadmill walking. The stimulation is triggered by specific gait events (heel strike, knee flexion, ankle dorsiflexion) detected through the MOCAP system and administered via a multichannel electrical stimulator. Conducted on healthy adults, this preliminary study focuses on assessing technical feasibility. We report different technical outcomes including the latency between gait event detection and the appearance of stimulation artifacts in EMG signals. The results confirm the viability of the system, laying the groundwork for future clinical application in the rehabilitation of children with CP.</div
Determined Blind Source Separation with Sinkhorn Divergence-based Optimal Allocation of the Source Power
No full textInternational audienceBlind source separation (BSS) refers to the process of recovering multiple source signals from observations recorded by an array of sensors. Common methods performing BSS, including independent vector analysis (IVA), and independent low-rank matrix analysis (ILRMA), typically rely on secondorder models to capture the statistical independence of source signals for separation. However, these methods generally do not account for the implicit structural information across frequency bands, which may lead to model mismatches between the assumed source distributions and the distributions of the separated source signals estimated from the observed mixtures. To tackle these limitations, this paper shows that conventional methods such as IVA and ILRMA can easily be leveraged by the Sinkhorn divergence, incorporating an optimal transport (OT) framework to adaptively adjust the estimated power spectral density (PSD) of the sources. This allows for the recovery of the source PSD while modeling the inter-band signal dependence and reallocating spectral power across frequency bands. As a result, enhanced versions of these methods are developed, integrating a Sinkhorn iterative scheme into their standard implementations. Extensive simulations demonstrate that the proposed methods consistently enhance BSS performance
The Human in Interactive Machine Learning: Analysis and Perspectives for Ambient Intelligence (Abstract Reprint)
No full textInternational audienceAs the vision of Ambient Intelligence (AmI) becomes more feasible, the challenge of designing effective and usable human-machine interaction in this context becomes increasingly important. Interactive Machine Learning (IML) offers a set of techniques and tools to involve end-users in the machine learning process, making it possible to build more trustworthy and adaptable ambient systems. In this paper, our focus is on exploring approaches to effectively integrate and assist human users within ML-based AmI systems. Through a survey of key IML-related contributions, we identify principles for designing effective human-AI interaction in AmI applications. We apply them to the case of Opportunistic Composition, which is an approach to achieve AmI, to enhance collaboration between humans and Artificial Intelligence. Our study highlights the need for user-centered and context-aware design, and provides insights into the challenges and opportunities of integrating IML techniques into AmI systems