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Selecting Energy-Efficient LED Retrofits with Optimal Color Qualities for New and Refurbished Buildings
No full textInternational audienceThis study carried out a literature search and selection in accordance with the PRISMA 2020 protocol to conduct a complete review of the literature describing the electrical, photometrical, and colorimetric parameters of LEDs. Based on it, a significant research gap was found in the field of LED-based lighting retrofits. We prove that there is a lack of publications indicating the relationship between the energy consumption of LED retrofits and user preferences concerning the quality of lighting. This article presents an effective new method for selecting LEDs to retrofit typical 3000, 4000, and 6500 K fluorescent lighting installations in buildings. It is shown that when selecting an LED replacement for a fluorescent source, consideration of the classically used parameters in the field of lighting technology to describe the quality of white light, specifically correlated color temperature and the color rendering index, is insufficient. We demonstrate that energy efficiency and the color preference criteria for retrofitted LEDs must be considered and balanced with the potential impact on circadian rhythms as assessed by the melanopic daylight efficacy ratio. This research proves that LED replacements with the best color preference properties (P1 class in the CPC classification of ANSI/IES TM 30-20 method) correspond to the least energy-efficient light sources
The Phantom Array Effect Explained Using Simple Formulas
No full textInternational audienceThe phantom array effect is a visual effect perceived by a human observer when making rapid eye movements across a light source exhibiting temporal light modulation at frequencies between about one hundred Hz and a few kHz: a series of multiple spurious images of the light source is seen in the direction of the eye saccade. This phenomenon may create discomfort when accomplishing visual tasks involving eye movements, such as driving or walking. In this paper, we provide a simple description of the phantom array effect by deriving formulas predicting its spatial and temporal features perceived in the field of view. This approach provides a framework to study how the visibility of the phantom array effect is influenced by the shape of the source, its luminance, the surrounding and background luminance, the modulation frequency and waveform, and the individual visual acuity
Interview de Christophe Martinsons : "lumière, santé et normes"
No full texthttps://www.lightzoomlumiere.fr/Physicien au CSTB et président de la CIE France, Christophe Martinsons explore la lumière, son impact sur la santé et comment les normes encadrent son usage
Effet des positions de mesurage sur les niveaux vibratoires et de bruit solidien dans les bâtiments soumis à des vibrations ferroviaires
No full textBruits solidiens dans les bâtiments dus aux sollicitations vibratoires extérieures; GABE - Acoustique du Bâtiment et de l'EnvironnementNational audienceDans le but d’améliorer le confort et même la santé des occupants de bâtiments proches de voies ferroviaires, il convient de prédire et de mesurer les niveaux vibratoires et de bruit solidiens pour les limiter notamment dans les logements. L’objectif de l’article 91 de la LOM de décembre 2019 de proposer un cadre réglementaire à ce sujet n’est pas encore atteint mais, il faut l’espérer, devrait l’être. Dans le présent travail, l’effet de la position de mesurage tant pour les niveaux vibratoires que pour le bruit solidien est étudié sur la base de modélisations numériques. Concernant les vibrations, il est généralement considéré un mesurage à mi-portée du plancher ; or cette position peut être difficile à déterminer ou à accéder, aussi un mesurage au centre d’un local est souvent effectué. Pour fixer un seuil acceptable pour les occupants, il convient de préciser une ou plusieurs positions du mesurage facilement identifiable et accessible et d’adapter le seuil limite à cette configuration de mesurage. La même problématique existe pour le bruit solidien. Sur la base des résultats obtenus, des propositions concernant les positions de mesurage pour les vibrations et le bruit solidien sont formulées
Stone masonry floor systems for low environmental impact structures
No full textInternational audienceStone masonry structures are relevant solutions to tackle buildings embodied impacts as they are low-processed materials. Although floor systems contribute to a large part of the greenhouse gas emissions of new constructions, stone floor systems are still little explored in recent constructions and their environmental impact has yet to be thoroughly assessed. This study integrates parametric design with Life Cycle Assessment for four stone floor typologies: Abeille vault, groin vault, stone floor with post-stressed stone beams, and post-stressed stone slabs. A comparison of stone structures with conventional floor systems, made using discernibility analysis, finds that stone floor systems can achieve up to a 60% reduction in embodied carbon compared to typical concrete floors. This result proves that stone floor systems can mitigate climate impacts. Further results indicate that stone masonry floor systems perform better than concrete and steel floors for human health, and better than wood floors for ecosystem quality. A sensitivity analysis highlights parameters such as transport logistics, energy usage in quarries, and stone cutting losses, suggesting that the structural design starting point should be the investigation of locally available material resources. Future work taking into account seismic and fire resistance as well as including detailed quarry impact on ecosystems could constitute relevant additions. This study shows the potential of stone floor systems for the decarbonisation of new building structures and highlights transport and production energy as key parameters to pilot GHG emissions of such structures
Radiation screens and their impact on air temperature measurement: a review
No full textInternational audienceOutdoor air temperature measurements are essential to be applied to agriculture, meteorology, hydrology, and urban planning. Precise measurements are particularly needed in the lower troposphere where the existence of large temperature gradients is prevalent. Urban temperature observation has been an area of research concern in recent years, particularly to study the urban heat island effect, local overheat, and heat reduction measures. Temperature readings most often employ sensors housed in protective shields. Low thermal inertia and fastresponding thermocouples and platinum probes, though less accurate, are two sensor types that are common. Shielding is used to minimize error by protecting sensors from precipitation and direct sunlight and allowing ventilation. Poor shielding can generate large temperature differences, over +4°C. Different shielding designs, such as Stevenson screens, Gill shields, and aspirated shelters, are investigated. Shielding efficiency depends upon their optical property, ventilation, and design. Correction methods like empirical corrections, numerical models including CFD, and neural network are also being considered to maximize data accuracy over urban areas. This paper offers an overview of studies that investigate radiation shields used for the measurement of external air temperatures and compare their performance in terms of various attributes. The methodology for selecting studies is presented first, encompassing field measurements, laboratory experiments, and numerical models. An inter-comparison of literature is then conducted, distinguishing commercially manufactured and home-made shields, ventilated and non-ventilated designs, and other significant features such as shape, size, optical properties, and materials. Errors in measurements, their reasons, and the procedures for correcting them are treated with special care
A Multidisciplinary Perspective on the Effects of Global Climate Change on Light Exposure and Health
No full textInternational audienceGlobal climate change is affecting our exposure to daylight and our use of lighting systems. Considering the increasingly frequent heat waves, the time spent indoors is predicted to increase dramatically. With more efficient solar shading, the available daylight in buildings may be reduced, possibly resulting in a deficiency in the necessary light for health. The growing use of shiftwork or nightwork during heat waves is also responsible for circadian misalignment and sleep debt. Under these conditions, lighting systems need to be adapted to promote wakefulness and the proper entrainment of the circadian timing system
Opinion of the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) on the risks to human health associated with the proliferation of Ostreopsis spp. on the Basque coast
No full textN/AInternational audienceIn France, the presence of marine microalgae of the genus Ostreopsis has been identified repeatedly on the Mediterranean coast for several years, whereas on the French Basque coasts its presence is much more recent. In the summers of 2021 and 2022, major Ostreopsis flowering episodes were reported on the Basque coast, resulting in several hundred cases of intoxication among holidaymakers and residents. The main route of human exposure is inhalation of aerosols, although it is not yet known whether the agents responsible for poisoning are Ostreopsis cells, cell debris, known toxins produced by Ostreopsis, or other as yet unidentified compounds. Other routes of exposure (dermal contact, eye contact, ingestion of contaminated water or seafood) are also possible. Poisoning is manifested through various signs and symptoms, occurring within 48 hours of exposure (Neurosensory and neurological, respiratory, dermal and digestive). This document presents the opinion of the French Agency for Food, Environmental and Occupational Health & Safety (ANSES), established from the work of its WATER and ERCA Expert Committees. ANSES received a request from the Directorate General for Health (DGS) and the Directorate General for Food (DGAL) to update knowledge about Ostreopsis that had been reported in the Agency's opinions from 2007 and 2008 (ANSES, 2007 and 2008), and draw up specific recommendations for managing Ostreopsis proliferation on the Basque coast. The literature review conducted as part of this expert appraisal revealed that knowledge about the genus Ostreopsis (diversity, biology, ecology, toxins produced) is still too fragmentary to characterise the hazard and risk to human health. Nevertheless to help local authorities affected by Ostreopsis blooms, Agency proposes a surveillance and quality monitoring strategy based on collaboration between site managers and the regional health agencies (ARSs), applicable to sites currently subject to bathing water quality monitoring and water sports sites that meet the conditions below
An analytical study of the impact of glazed vs diffuse facades on solar trapping with detailed directional radiation model
No full textInternational audienceThe optical properties of building envelopes govern the inward and outward energy fluxes of a city; and therefore play a major role in urban overheating due to solar trapping. High reflectance (cool) materials have demonstrated a reduction in surface temperature of roofs with a high sky view factor, but their effects are limited to the upper floors of the buildings. To address the root cause of solar trapping, we must focus our attention on facades and roads, as these are the surfaces that contribute to multireflections in densely populated areas. We will showcase the interrelation between the shortwave optical properties of facades and the leading reflections within the canyon.We have developed an analytical urban canyon model that integrates a detailed angular shortwave radiation description of materials. We aim to quantify the impact of the optical properties of building facades on solar trapping by analyzing the directionality of their reflections. We track the irradiance reflected toward the road and toward the buildings, as they will affect pedestrian thermal comfort and building cooling needs, respectively. We consider traditional materials (lambertian and specular) to evaluate the current situation, and innovative materials (retroreflective) to envision solar trapping mitigation strategies. Simulations are performed with an hourly time step for a year time period.To verify the consistency of the model, we present the results for a mediterranean compact midrise neighborhood (H/W =1). During summer, for East-West facade orientations, glazed facades contribute to a 15 % increase of ground peak irradiance (equivalent to 85 W/m 2 ) compared to typical lambertian facades. The contribution of solar irradiance to thermal stress is evaluated with temperature sol-air indicator. Specular canyons result in a rise of 2 • C in peak sol-air temperature. For a typical meteorological year, specular facades increase by 11 % (155) the sol-air degree-hours above 26 • C, and increase by 132 % (145) the degree-hours above 40 • C compared to lambertian facades. Future studies will focus on measuring the impact on thermal comfort and building energy performance at neighborhood scale.</p
Mise en œuvre des techniques de traitement du langage naturel pour l'extraction et la formalisation automatique d'exigences dans le domaine de la construction
No full textIn the construction sector, managing technical requirements often relies on unstructured documents, such as the Cahier des Clauses Techniques Particulières (CCTP), a contractual document specifying the requirements that buildings must adhere to. However, manually extracting information from these documents is a lengthy and error-prone process, complicating their integration into automated compliance verification systems. The emergence of GPT-3 in early 2023 marked a turning point in Natural Language Processing (NLP), introducing advanced capabilities in information extraction and text comprehension, challenging traditional methods and the initial expectations of this thesis. The power of GPT-3 and its successor, GPT-4, revealed simpler and more accessible extraction solutions, no longer requiring the same level of technical expertise in NLP as before.In response to these advances, this thesis developed a methodological framework to automate the extraction of technical requirements and evaluate the effectiveness of GPT-4 and other models compared to more traditional methods through a benchmarking process. The methodology includes creating an annotated database of CCTPs for model training and validation, followed by Named Entity Recognition (NER) and Relation Extraction (RE) techniques to identify and link relevant technical entities. Advanced models such as CamemBERT and GPT-4 were adapted to the construction domain through transfer learning and prompt engineering, while more traditional Machine Learning methods, such as the Random Forest (RF) model, were also tested for RE tasks.The results show that after fine-tuning, CamemBERT achieved F1-scores above 96% for NER, while the RF model reached an F1-score of 83% for RE, outperforming GPT-4, which scored 74%. Although GPT-4, using few-shot learning, did not surpass fine-tuned models, its performance remains promising, particularly in achieving competitive results with few examples, opening new perspectives.The extracted entities and relationships are structured for direct integration into compliance verification systems, especially for Building Information Modeling (BIM), allowing for the automatic verification of requirements extracted from CCTPs against digital models. This system ensures more efficient and consistent requirements management, reducing the manual interventions needed to maintain alignment between BIM models and contractual documents.These results open avenues for improving the proposed framework. In particular, creating an extraction system based on a Retrieval-Augmented Generation (RAG) approach could leverage the capabilities of Large Language Models (LLMs), such as GPT, to further improve performance even with limited annotated data. Additionally, the developed framework provides a solution for handling unstructured documents by transforming textual requirements into machine-readable information, facilitating a transition toward Model-Based Requirements Engineering (MBRE). This approach supports smoother collaboration between stakeholders throughout the project lifecycle, enhancing the traceability and consistency of requirements.Dans le domaine de la construction, la gestion des exigences techniques repose souvent sur des documents non structurés, tels que le Cahier des Clauses Techniques Particulières (CCTP), un document contractuel qui spécifie les exigences auxquelles les bâtiments doivent se conformer. Cependant, l’extraction manuelle de ces informations reste un processus long et sujet aux erreurs, rendant difficile leur intégration dans des systèmes automatisés de vérification de conformité. L’émergence de GPT-3 au début de 2023 a marqué un tournant dans le domaine du Traitement Automatique du Langage Naturel (TALN), en introduisant des capacités avancées d’extraction d’information et de compréhension de texte, remettant ainsi en question les méthodes traditionnelles et les attentes de cette thèse. La puissance de GPT-3 et de son successeur GPT-4 a révélé des solutions d'extraction plus simples et plus accessibles, ne nécessitant plus les mêmes compétences techniques en TALN qu’auparavant.En réponse à ces avancées, cette thèse a développé un cadre méthodologique pour automatiser l'extraction des exigences techniques et évaluer l’efficacité de GPT-4 et d’autres modèles par rapport aux méthodes plus classiques, à travers un processus de benchmarking. La méthodologie comprend la création d’une base de données annotée de CCTPs pour l’entraînement et la validation des modèles, suivie de techniques de Named Entity Recognition (NER) et de Relation Extraction (RE) pour identifier et relier les entités techniques. Des modèles avancés tels que CamemBERT et GPT-4 ont été adaptés au domaine de la construction via l’apprentissage par transfert et le Prompt Engineering, tandis que des méthodes de Machine Learning plus classiques, comme le modèle Random Forest (RF), ont également été testées pour la tâche de RE.Les résultats montrent qu’après un fine-tuning, CamemBERT a atteint des F1-scores supérieurs à 96 % pour la NER, tandis que le modèle RF a obtenu un F1-score de 83 % pour la RE, surpassant GPT-4, qui a obtenu un score de 74 %. Bien que GPT-4, en utilisant le Few-shot Learning, n’ait pas surpassé les modèles fine-tunés, ses performances restent intéressantes, en particulier sa capacité à atteindre des résultats compétitifs avec peu d’exemples, ce qui ouvre de nouvelles perspectives.Les entités et relations extraites sont structurées pour une intégration directe dans des systèmes de vérification de conformité, notamment pour le Building Information Modeling (BIM), permettant de vérifier automatiquement les exigences extraites des CCTPs par rapport aux modèles numériques. Ce système assure une gestion des exigences plus efficace et cohérente, réduisant ainsi les interventions manuelles nécessaires pour maintenir la conformité entre le BIM et les documents contractuels.Ces résultats ouvrent des pistes d’amélioration pour le cadre proposé. En particulier, la création d’un système d’extraction basé sur une approche Retrieval-Augmented Generation (RAG) pourrait exploiter les capacités des Large Language Models (LLMs), comme GPT, pour améliorer encore les performances, même avec des données annotées limitées. Le cadre développé offre également une solution pour traiter les documents non structurés en transformant les exigences textuelles en informations exploitables par machine, facilitant ainsi une transition vers une ingénierie des exigences basée sur des modèles (Model-Based Requirements Engineering - MBRE). Cette approche soutient une collaboration plus fluide entre les parties prenantes tout au long du cycle de vie des projets de construction, renforçant la traçabilité et la cohérence des exigences