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ADF & TransApp: A Transformer-Based Framework for Appliance Detection Using Smart Meter Consumption Series
No full textInternational audienceOver the past decade, millions of smart meters have been installed by electricity suppliers worldwide, allowing them to collect a large amount of electricity consumption data, albeit sampled at a low frequency (one point every 30min). One of the important challenges these suppliers face is how to utilize these data to detect the presence/absence of different appliances in the customers' households. This valuable information can help them provide personalized offers and recommendations to help customers towards the energy transition. Appliance detection can be cast as a time series classification problem. However, the large amount of data combined with the long and variable length of the consumption series pose challenges when training a classifier. In this paper, we propose ADF, a framework that uses subsequences of a client consumption series to detect the presence/absence of appliances. We also introduce TransApp, a Transformer-based time series classifier that is first pretrained in a self-supervised way to enhance its performance on appliance detection tasks. We test our approach on two real datasets, including a publicly available one. The experimental results with two large real datasets show that the proposed approach outperforms current solutions, including state-of-the-art time series classifiers applied to appliance detection
Numerical investigation of the mainly axial flow in mixed convection regime within tube bundles
No full textInternational audienceWall-resolved Large-Eddy Simulation (WRLES) is carried-out to investigate the turbulent mixed convection in the upward flow within tube bundles, a configuration representative of a real scenario in a nuclear reactor. A database of first and second-order turbulence statistics is set-up. Interesting physical phenomena triggered by the buoyancy forces in the spatially developing flow are also highlighted
A CFD Study on Different Configurations of Spacer-Filled Membrane Distillation System Using OpenFOAM
No full textInternational audienceCircular economy initiatives like the EC funded iWAYS project (grant agreement: 958274) promote the reuse of waste heat in industrial sites. This presents opportunities and challenges for technological adaptation. Membrane distillation (MD) is a thermally driven process for water treatment that can use waste heat. However, effectively treating complex industrial wastewater requires adapting MD units to achieve reliable and efficient performance. Filament spacers within the MD units play a key role in structural maintenance and flow mixing. CFD simulations can help to characterize filament spacer configuration impacts on the hydrodynamic of feed and permeate channels, which affects both trans-membrane temperature gradient and membrane fouling control. Here, we performed a CFD study on a direct contact membrane distillation (DCMD) sub-unit with the goal of evaluating impact on robustness and performance of a set of designed filament spacer configurations. The modeled membrane distillation system has an overall length of 200 mm, width of 10 mm and height of 4.1 mm, containing two layers of filaments in each of the feed and permeate channels. The diameter of the filaments was 1 mm, and they had a 45• degree angle to the flow direction in the channels.Variations of this standard filament configuration were also tested and simulated to optimize their mixing performance.The numerical simulations to approximate in a 3D solution of Navier-stokes equations for steady state conditions were performed using OpenFOAM code. The computational domains were meshed using OpenFOAM snappyHexMesh utility, and finite-volume based simulation relying on the chtMultiRegionFoam solver was executed in parallel over 40 CPU cores. Comparing the CFD analysis of different filaments´ configurations lead to an assessment of an improved spacer structure. The selected configuration is to be 3D printed for laboratory-scale experimental confirmation of the validity of the CFD model and the optimal configuration finding.</p
Improvement of an acoustic method for monitoring the pressure and composition of the fission gas in the rods of a PWR assembly in a nuclear spent fuel pool
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Consensus hydrologique de la tempête ALEX du 2 et 3 octobre 2020 dans les Alpes-Maritimes
No full textInternational audienceFollowing the catastrophic floods on 2 and 3 October 2020, in the Alpes-Maritimes department, Cerema has been asked to coordinate a hydrological expertise on the Var and Roya river basins. It was carried out within the framework of a technical post-event survey (RETEX) led by the Departmental Directorate of Territories and the Sea (DDTM 06) on behalf of the Prefect of the Alpes-Maritimes. The main results, which were the subject of a consensus with the partners, make it possible to characterise the ALEX event for the Est & eacute;ron, Tin & eacute;e, V & eacute;subie, Var and Roya rivers. The consensus work was based on a graphical comparison between various approaches provided by different organisations. The aim was to facilitate the visualisation of the differences between the various estimations of peak flows to reach a consensus. The final result provides peak flow graphs by valley with low and high estimations. This allows a common sharing of information associated with flow uncertainties on this type of flood event, especially in a torrential context.Suite aux inondations catastrophiques les 2 et 3 octobre 2020 dans le département des Alpes- Maritimes, le Cerema a été chargé de coordonner une expertise hydrologique sur les bassins versants du Var et de la Roya. Elle a été réalisée dans le cadre d’un retour d’expérience (RETEX) technique piloté par la Direction Départementale des Territoires et de la Mer (DDTM 06) pour le compte du Préfet des Alpes-Maritimes. Les principaux résultats, qui ont fait l’objet d’un consensus avec les partenaires, permettent de caractériser l’évènement ALEX pour les vallées de l’Estéron, de la Tinée, de la Vésubie, du Var et de la Roya. Le travail de consensus s’est appuyé sur une comparaison graphique de diverses approches d’estimations provenant des différents organismes impliqués. L’objectif était de faciliter la visualisation des convergences et divergences des multiples estimations de débits de pointe pour aboutir à un consensus. Le résultat final permet la fourniture de graphiques de débit de pointe par vallée avec des estimations basses et hautes. Cela permet un partage commun d’information associé à des incertitudes des débits sur ce type de retour d’expérience, en particulier dans un contexte torrentiel
An Overview on Nocardiopsis Species Originating From North African Biotopes as a Promising Source of Bioactive Compounds and In Silico Genome Mining Analysis of Three Sequenced Genomes
No full textInternational audienceActinobacteria are renowned for their prolific production of diverse bioactive secondary metabolites. In recent years, there has been an increasing focus on exploring “rare” genera within this phylum for biodiscovery purposes, notably the Nocardiopsis genus, which will be the subject of the present study. Recognizing the absence of articles describing the research process of finding bioactive molecules from the genus Nocardiopsis in North African environments. We, therefore, present a historical overview of the discoveries of bioactive molecules of the genus Nocardiopsis originating from the region, highlighting their biological activities and associated reported molecules, providing a snapshot of the current state of the field, and offering insights into future opportunities and challenges for drug discovery. Additionally, we present a genome mining analysis of three genomes deposited in public databases that have been reported to be bioactive. A total of 36 biosynthetic gene clusters (BGCs) were identified, including those known to encode bioactive molecules. Notably, a substantial portion of the BGCs showed little to no similarity to those previously described, suggesting the possibility that the analyzed strains could be potential producers of new compounds. Further research on these genomes is essential to fully uncovering their biotechnological potential. Moving forward, we discuss the experimental designs adopted in the reported studies, as well as new avenues to guide the exploration of the Nocardiopsis genus in North Africa
From user to operator: Rationalizing the charging infrastructure deployment. A case study of Berlin
No full textInternational audienceThe urge to develop greener transportation necessitates a shift from internal combustion engine vehicles to electric vehicles (EVs). Ensuring user acceptance of EVs through adequate charging infrastructure is crucial for this transition. We hypothesize that a user-oriented, time and space-coherent deployment of charging stations can reduce range anxiety and enhance EV adoption. We present a new multi-criteria deployment model and apply it through a MATSim multi-agent simulation to the Berlin region, observing the effects of different user behaviors on the charging infrastructure deployment. Results indicate that slow chargers are more cost-efficient and that residential charging is vital for user acceptance of EVs. The study concludes that a well-planned deployment schedule significantly reduces range anxiety and supports a coherent charging infrastructure helping EV democratization
Clarifying the murk: unveiling bacterial dynamics in response to crude oil pollution, Corexit-dispersant, and natural sunlight in the Gulf of Mexico
No full textInternational audienceThe 2010 Deepwater Horizon (DwH) Oil spill released an enormous volume of oil into the Gulf of Mexico (GoM), prompting the widespread use of chemical dispersants like Corexit ® EC9500A. The ecological consequences of this treatment, especially when combined with natural factors such as sunlight, remain unexplored in the context of marine bacterial communities' dynamics. To address this knowledge gap, our study employed a unique metaproteomic approach, investigating the combined effects of sunlight, crude Macondo surrogate oil, and Corexit on GoM microbiome across different mesocosms. Exposure to oil and/or Corexit caused a marked change in community composition, with a decrease in taxonomic diversity relative to controls in only 24 hours. Hydrocarbon (HC) degraders, particularly those more tolerant to Corexit and phototoxic properties of crude oil and/or Corexit, proliferated at the expense of more sensitive taxa. Solar radiation exacerbated these effects in most taxa. We demonstrated that sunlight increased the dispersant's toxicity, impacting on community structure and functioning. These functional changes were primarily directed by oxidative stress with upregulated proteins and enzymes involved in protein turnover, general stress response, DNA replication and repair, chromosome condensation, and cell division. These factors were more abundant in chemically treated conditions, especially in the presence of Corexit compared to controls. Oil treatment significantly enhanced the relative abundance of Alteromonas, an oil-degrading Gammaproteobacteria. In combined oil-Corexit treatments, the majority of identified protein functions were assigned to Alteromonas, with strongly expressed proteins involved in membrane transport, motility, carbon and amino acid metabolism and cellular defense mechanisms. Marinomonas, one of the most active genera in dark conditions, was absent from the light treatment. Numerous metabolic pathways and HC-degrading genes provided insights into bacterial community adaptation to oil spills. Key enzymes of the glyoxylate bypass, enriched in contaminant-containing treatments, were predominantly associated with Rhodobacterales and Alteromonadales. Several proteins related to outer membrane transport, photosynthesis, and nutrient metabolisms were characterized, allowing predictions of the various treatments on biogeochemical cycles. The study also presents novel perspectives for future oil spill clean-up processe
140-year daily ensemble streamflow reconstructions over 661 catchments in France
No full textInternational audienceAbstract. The recent development of the FYRE climate (French Hydroclimate REanalysis), a high-resolution ensemble daily reanalysis of precipitation and temperature covering the period 1871–2012 and the whole of France, offers the opportunity to derive streamflow series over the country from 1871 onwards. The FYRE Climate dataset has been used as input for hydrological modelling over a large sample of 661 near-natural French catchments using the GR6J lumped conceptual model. This approach led to the creation of the 25-member hydrological reconstructions HyDRE spanning the 1871–2012 period. Two sources of uncertainties have been taken into account: (1) the climate uncertainty by using forcings from all 25 ensemble members provided by FYRE Climate, and (2) the streamflow measurement error by perturbing observations used during the calibration. The hydrological model error based on the relative discrepancies between observed and simulated streamflow has been further added to derive the HydREM streamflow reconstructions. These two reconstructions are compared to other hydrological reconstruction with different meteorological inputs, hydrological reconstructions from machine learning algorithm and independent/dependent observations. Overall the results show the added value of the HydRE and HydREM reconstructions in terms of quality, uncertainty estimation, and representation of extremes, therefore allowing to better understand the variability of past hydrology over France
Imaging a dam-rock interface with inversion of a full elastic-acoustic model
No full textInternational audienceWe are interested in imaging the interface between the concrete structure of hydroelectric dams and the rock foundation using non-destructive seismic waves. We present a geophysical technique for processing seismic measurements to obtain an image of the interface with metric resolution. The proposed technique is based on "Full Waveform Inversion" with a shape optimization approach. Numerical results using synthetic measurements demonstrate the method ability to accurately recover the interface with a limited number of measurement points and in the presence of noise