HAL-Université de Bretagne Occidentale
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Machine Learning Approaches to Predicting Corporate Green, Social, and Sustainability Bond Issuance
No full textThis study investigates the factors driving corporate green, social, sustainability, and sustainability-linked bond issuances (GSSS bonds) through an advanced machine learning framework that balances predictive accuracy and interpretability. By analyzing GSSS bonds issued by non-financial corporations across 51 countries from 2013 to 2024, the research highlights the effectiveness of Random Forest (RF) and XGBoost for prediction and Multinomial Logistic Regression (MLR) for model transparency. Feature importance analysis using SHAP values and Partial Dependence Plots (PDPs) identifies key drivers, including firm size, governance quality, ESG performance, and macroeconomic factors such as GDP per capita and inflation. The findings demonstrate RF's superior predictive accuracy, with larger firms and robust governance frameworks emerging as dominant influences on GSSS bond issuance.Europe's leadership in sustainable finance further underscores the importance of strong regional frameworks. These insights provide practical guidance for issuers, investors, and policymakers, offering a roadmap to enhance sustainable finance strategies while contributing to global environmental and social objectives.</div
Characterization of single reed mouthpiece interaction in quasi-static regime
No full textInternational audienceThis paper describes an experimental measurement setup for the characterization of single-reed mouthpiece interaction under quasi-static conditions. Measurement leads to the estimation of the nonlinear characteristics, establishing the relation between pressure drop across the reed channel and the jet cross-section. Measurements with various lip forces show that the resultant nonlinear characteristics can be described by a single nonlinear characteristic linking the generalized pressure and the jet cross-section. This generalized pressure is the sum of the pressure drop and the lip pressure, defined as the lip force divided by an equivalent lip surface determined for each reed. The nonlinear characteristic is then modeled as a function depending on three parameters: the opening at rest, the linear stiffness for low pressures, and the “elbow pressure,” which allows to make the link between the two affine parts of the function. The characterization of 24 tenor saxophone reeds shows that the model fits the experimental characteristics with an inaccuracy that can be considered as a supplementary parameter for the reed. Finally, the reeds can be characterized with with only five parameters, the inaccuracy, the lip equivalent surface and the three parameters of the nonlinear model. First results suggest that equivalent lip surface and inaccuracy depends on the reed type while reed opening at rest and linear stiffness depends on the reed
History of the Sedimentary Regimes of the Aquitaine Margin (Bay of Biscay, France) at the Outlet of its Main Tributaries During the Last Millennium: A Mirror of the North Atlantic and European Climates
No full textL'Encyclopédie des communautés et pratiques communautaires: Extraits choisis – Édition 2025
No full textInternational audienceL’Encyclopédie des communautés et pratiques communautaires propose un corpus inédit de connaissances sur les sources, formes et modes d’organisations collaboratives et collectives d’hier, d’aujourd’hui et de demain.Rassemblant des spécialistes internationaux de diverses disciplines, dont le droit, la sociologie, l’économie ou les sciences de la gestion, cet ouvrage de référence constitue une ressource précieuse pour comprendre et analyser les fondements et fonctionnements des communautés qui imaginent de nouvelles façons de vivre ensemble.Ainsi les communautés dont il est question ici sont celles qui s’articulent autour de trois axes : la défense d’un intérêt communautaire, comme la protection d’un espace naturel ; le partage d’un bien privatif ou commun, comme les habitats participatifs ; ou encore la production des connaissances, telle l’encyclopédie Wikipédia.Publiée en libre accès, cette encyclopédie évolutive, dont sont présentés ici les premiers extraits, a vocation à s’enrichir continuellement sous la supervision d’un comité scientifique international et pluridisciplinaire, afin d’offrir unevision plurielle et engagée des communautés et pratiques communautaires
Parametrization of renormalized models for singular stochastic PDEs
No full textLet T be the regularity structure associated with a given system of singular stochastic PDEs. The paracontrolled representation of the Π map provides a linear parametrization of the nonlinear space of admissible models M = (g, Π) on T , in terms of the family of para-remainders used in the representation. We give an explicit description of the action of the most general class of renormalization schemes on the parametrization space of the space of admissible models. The action is particularly simple for renormalization schemes associated with degree preserving preparation maps. The BHZ renormalization scheme has that property
Specialized Scalar and SIMD Instructions for Error Correction Codes Decoding on RISC-V Processors
No full textInternational audienceThe rapid deployment of Internet-of-Things (IoT) devices for a few years has been impressive, and the progressive deployment of 5G will accelerate things even further. Indeed, this standard opens the door to a new generation of standards aimed at a convergence of networks and communication protocols (WiFi, LTE, 4G etc.). This results in the need for flexible implementations of different families of codes, such as, LPDC, NB-LDPC, turbo codes and polar codes. In this context, the work presented in this article proposes the design of a flexible instruction set processor for an IoT context. The objective is to improve the performance level of low-complexity processor cores through instruction set extensions for Error Correction Code (ECC) decoding. The approach discussed is supported by experimental results obtained based on a RISC-V architecture to which specific instruction sets have been added. The results demonstrate a reduction in the required processing clock cycles up to 44.1% for polar codes, 39.2% for LDPC codes, 21.8% for NB-LDPC codes, and 24.3% for turbo codes (4G LTE) codes with a classical Single Instruction Single Data (SISD) approach. Moreover, Single Instruction Multiple Data (SIMD) parallelization strategy enables execution time savings that are far more impressive. The number of clock cycles required to decode a data bit is reduced by 65.6% to 76.9%, with a limited hardware over-cost from 0.6% to 34% (depending on the error correction code family and the targeted RISC-V core).</div
Impact of Convectively Coupled Tropical Waves on the composition and vertical structure of the atmosphere above Cabo Verde in September 2021 during the CADDIWA campaign
No full textInternational audienceIn summer, Mixed Rossby Gravity Waves/Tropical Disturbances (MRG-TD) are known to drive intraseasonal humidity variability in the northeastern Atlantic troposphere, modulated by Equatorial Rossby (ER) and Kelvin waves. However, their impact on dust remains poorly understood, and MRG-TD tracks are often mingled in the literature. During the Clouds-Atmosphere Dynamics-Dust Interaction in West Africa (CADDIWA) campaign in September 2021, in-situ and remote sensing data (dropsondes, radiosondes, GNSS, and IASI) were used to investigate the 3D impact of tropical waves on dust and thermodynamics over Cape Verde. The distinct contributions of Kelvin waves, ER, and MRG-TD were isolated using frequency-wave number filtering of Total Column Water Vapor (TCWV). The latter was efficiently split into southern and northern-track African Easterly Waves using distinct frequency windows (respectively MRG-TD1 and MRG-TD2) and enabled us to demonstrate their distinct horizontal structures and impacts. ER waves mainly impacted thermodynamics above 750 hPa, MRG-TD1 affected jet-level thermodynamics, and MRG-TD2 modulated moisture in the lower troposphere. MRG-TD2 was identified as the main driver of dust events over Cape Verde in September 2021. Tropical cyclogenesis was linked to interactions among multiple tropical waves. Notably, a delay of up to 2 days was observed between Kelvin wave interactions with MRG-TD1 and cyclone formation, consistent with previous findings. These results highlight the critical role of tropical wave interactions in cyclogenesis and underscore their potential for improving forecasting
L'équipement informatique des familles calédoniennes et les usages des écrans des adolescents de 11 à 15 ans
No full textSynthèse visuelle des données relatives à l'équipement digital et à l'usage des écrans chez les adolescents vivant en Nouvelle-Calédonie et âgés de 11 à 15 ans. Les données ont été obtenues dans le cadre du projet scientifique : Cultures et comportements alimentaires de la jeunesse dans les pays francophones du Pacifique au XXIème siècle : exemple de la Nouvelle-CalédonieVisual summary of data on digital equipment and screen use among teenagers aged 11 to 15 living in New Caledonia. The data was obtained as part of the scientific project : "Cultures et comportements alimentaires de la jeunesse dans les pays francophones du Pacifique au XXIème siècle : exemple de la Nouvelle-Calédonie" [Eng: "Eating cultures and behaviors of young people in French-speaking Pacific countries in the 21st century: the example of New Caledonia"]Synthèse visuelle des données relatives à l'équipement digital et à l'usage des écrans chez les adolescents vivant en Nouvelle-Calédonie et âgés de 11 à 15 ans. Les données ont été obtenues dans le cadre du projet scientifique : "Cultures et comportements alimentaires de la jeunesse dans les pays francophones du Pacifique au XXIème siècle : exemple de la Nouvelle-Calédonie
Moyenner sur les cercles le champ libre gaussien dans le disque de Poincaré
No full textThe gaussian free field on the unit disk D can be seen as a two-dimensional version of the Brownian bridge on the interval [0,1]. It is intrinsically associated with the Sobolev space H_0^1 (D). To define the latter, we can choose any metric conformally equivalent to the Euclidean metric on D. This note is an introduction to the gaussian free field on the unit disk whose aim is to highlight some of the conveniences offered by hyperbolic geometryon D to describe the first properties of this probabilistic object.Le champ libre gaussien sur le disque unité D peut être appréhendé comme une version bi-dimensionnelle du pont brownien sur l'intervalle [0, 1]. Il est intrinsèquement associé à l'espace de Sobolev H_0^1 (D). Pour définir ce dernier, on peut choisir n'importe quelle métrique conformément équivalente à la métrique euclidienne sur D. Cette note est une introduction au champ libre gaussien sur le disque unité dont le but est de mettre en évidence quelques commodités qu'offre la géométrie hyperbolique sur D pour décrire les premières propriétés de cet objet probabiliste
