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Optimal Contracts under Moral Hazard, Adverse Selection and Limited Liability
No full textNational audienceA buyer (the principal) procures a good or service from a risk-neutral seller (the agent). The seller, protected by limited liability, has private information on his marginal cost of production (adverse selection), and exerts a non-verifiable effort that increases surplus (moral hazard). Even when the effort and production technologies are separable, the optimal contract always mixes features that are found separately under with pure moral hazard or pure screening. Screening distortions are mitigated in comparison with the pure screening scenario with the possibility of bunching for the least efficient types even in contexts where full separation would be obtained with pure screening. Effort distortions are also used as a screening device. In comparison with a pure moral hazard scenario, those distortions may be lessened for the most efficient types, up to the point of possibly allowing implementation of the first-best effort, while they are worsened for the worst types. Although our analysis is cast in a simple procurement setting, we illustrate our findings in other economic environments of general interest including economic and environmental regulation, financial contracting, provision of quality in services, and price discrimination
Proper Scoring Rules for Multivariate Probabilistic Forecasts based on Aggregation and Transformation
No full textInternational audienceProper scoring rules are an essential tool to assess the predictive performance of probabilistic forecasts. However, propriety alone does not ensure an informative characterization of predictive performance, and it is recommended to compare forecasts using multiple scoring rules. With that in mind, interpretable scoring rules providing complementary information are necessary. We formalize a framework based on aggregation and transformation to build interpretable multivariate proper scoring rules. Aggregation-and-transformation-based scoring rules can target application-specific features of probabilistic forecasts, which improves the characterization of the predictive performance. This framework is illustrated through examples taken from the weather forecasting literature, and numerical experiments are used to showcase its benefits in a controlled setting. Additionally, the framework is tested on real-world data of postprocessed wind speed forecasts over central Europe. In particular, we show that it can help bridge the gap between proper scoring rules and spatial verification tools
Franchisees' adoption of omnichannel marketing
No full textInternational audienceThe widespread use of digital technologies and changes in consumer behavior have fueled the development of omnichannel marketing, which has become a widely adopted market standard. However, adopting such strategies within franchise networks remains challenging, as it requires both franchisors and franchisees to embrace omnichannel marketing. Drawing on the Theory of Planned Behavior, this paper investigates the factors driving franchisees' adoption of omnichannel marketing. In-depth interviews with 23 franchisees and 20 franchisor executives and managers reveal that franchisee adoption is determined by a complex interplay of attitudes toward omnichannel marketing, subjective norms, and perceived behavioral control. The findings also emphasize several perceptual gaps between franchisors and franchisees regarding the determinants of franchisee adoptionfor instance, franchisors often overestimate how franchisees perceive omnichannel as a growth driver.La généralisation des technologies numériques et l’évolution des comportements des consommateurs ont favorisé l’essor du marketing omnicanal, désormais établi comme un standard de marché largement adopté. Toutefois, sa mise en œuvre au sein des réseaux de franchise demeure problématique, dans la mesure où elle requiert l’implication conjointe des franchiseurs et des franchisés. Mobilisant la théorie du comportement planifié, cet article analyse les facteurs déterminants de l’adoption du marketing omnicanal par les franchisés. Des entretiens approfondis menés auprès de 23 franchisés et de 20 cadres et dirigeants de structures franchiseurs révèlent que cette adoption résulte d’une interaction complexe entre les attitudes à l’égard du marketing omnicanal, les normes subjectives perçues et le sentiment de contrôle comportemental. Les résultats mettent également en évidence plusieurs écarts de perception entre franchiseurs et franchisés quant aux déterminants de l’adoption : les franchiseurs tendent notamment à surestimer la manière dont les franchisés perçoivent l’omnicanal en tant que vecteur de croissance
A preliminary anthraco-entomological study of the charred woods of Notre-Dame de Paris (France): Towards an assessment of the degradation state of medieval and modern-day roof frames based on woodborer traces
No full textInternational audienceThe terrible blaze of Notre-Dame de Paris cathedral on 15 April 2019 fostered the gathering of an important consortium of researchers, especially on the subject of timber, through ANR project CASIMODO (coord. A. Dufraisse, MNHN, BioArch UMR 7209). Characterisation of the bio-infestations of the roof frame was one of the many lines of research that ensued from the blaze. Notre-Dame de Paris is admittedly free of any attack by woodborers. Yet, this only reflects the absence of studies on the subject, apart from a few annotations on the architectural surveys of the main trusses carried out by R. Fromont and C. Trentesaux (2015). The aim of the present article is to propose a first overview of infestations of medieval and modern-day roof frames by pests (woodborers and lignin-degrading fungi) through the observation of 821 pieces of timber. The impact of recurrent infestations of the underside of the lower pieces of trusses (wall plates and truss beams) provides evidence of insufficient imperviousness of the building. The resulting water infiltrations drenched the wood and allowed for the settlement and the development of 11,580 insects. The longevity of this structure – nearly 800 years for some pieces – makes it tricky to date back and understand these infestations and gives rise to several questionings, particularly on the methodological aspects of the anthraco-entomological approach
Estimating weak Markov-switching AR(1) models
No full textIn this paper, we present the asymptotic properties of the moment estimator for autoregressive (AR for short) models subject to Markovian changes in regime under the assumption that the errors are uncorrelated but not necessarily independent. We relax the standard independence assumption on the innovation process to extend considerably the range of application of the Markov-switching AR models. We provide necessary conditions to prove the consistency and asymptotic normality of the moment estimator in a specific case. Particular attention is paid to the estimation of the asymptotic covariance matrix. Finally, some simulation studies and an application to the hourly meteorological data are presented to corroborate theoretical work
La digitalisation de la comptabilité : une revue de la littérature des impacts, facteurs et dimensions spatio-temporelles
No full textThème du congrès : « Normes, représentations et comportements »International audienc
La Transformation Numérique Responsable : vecteur de changement organisationnel au sein des universités
No full textThème du congrès : « Le management public responsable et intégré : entre tradition et innovation »International audienc
La relation à la marque du Z consommateur : une étude exploratoire des causes de détachement
No full textNational audienceThe objective of this qualitative research, conducted with 130 GenZers, and using consumer narratives, is to explore the reasons of brand attachment and brand detachment of this specific group. The analysis of the data collected,analyzed through the prism of the functional attitude theories, highlights different factors according to the product category to which the mentioned brands relate (ready-to-wear vs. food) and underlines that the reasons which anchored attachment are not always those that explain detachment. More specifically, if the utilitarian function is the most prominent in justifying attachment, the expression of values, not only ethical but also related to identity, becomes more significant in explaining detachment from fashion brands, while it is the ego-defensive function that dominates when it comes to food. Recommendations for brand managers are provided in order to meet consumer expectations and anticipate brand detachment.L’objectif de cette recherche qualitative, menée auprès de 130 consommateurs de la génération Z par l’approche des récits de consommation, est d’explorer les raisons de l’attachement à la marque et du détachement pour ces consommateurs. L’analyse des données, via le prisme des théories fonctionnelles des attitudes, permet de préciser les types de facteurs en fonction de la catégorie de produit à laquelle se rattachent les marques citées (prêt-à-porter vs alimentaire) et de montrer que les raisons qui fondent l’attachement ne sont pas toujours celles qui expliquent le détachement. En particulier, si la fonction utilitaire est la plus saillante pour justifier l’attachement, l’expression de valeurs éthiques mais surtout identitaires, devient plus prégnante pour expliquer le détachement des marques de vêtements, tandis que c’est la défense de l’égo qui domine pour l’alimentaire. Un ensemble de recommandations est proposé pour répondre aux attentes des consommateurs et d’anticiper le détachement de la marque
Enhancing Image Quality to Improve Medical Image Classification: Application to Nuclear Medicine Planar Images
No full textInternational audienceNuclear Medicine images are obtained by injecting small amounts of radio-tracers into the body to track specific organs. Particular cameras detect radiations emitted from the radio-tracers resulting in images that visualize the function of the organs rather than their structure. The association of the cameras and radio-tracers causes low resolution and low signal-to-noise ratio, therefore, the images are often of poor quality. Image Quality Enhancement (IQE) is one possible solution to this problem as it improves the clarity of the images by removing noise and correcting distortions. In this paper, we propose a methodology based on artificial intelligence (AI) with the integration of an IQE step for the detection of normal/abnormal parathyroid glands. Two different IQE techniques are employed, one based on a statistical filter and the other on AI. The enhanced images are processed with a Convolutional Neural Network (CNN), and Lasso regression for features extraction and selection. F inally, several AI models are used for binary image classification. The obtained results achieved an accuracy of 83% in distinguishing normal/abnormal parathyroid glands. IQE step significantly improves the accuracy of the AI model by 16.9% over the initial accuracy of 71%, demonstrating the importance of IQE in assessing image classification performance
ECSPLORER, Electronuclear System for Space: Reactor Studies for Performance Optimiz
No full textInternational audienceIn the frame of a collaboration with the French National Centre of Space Studies (CNES) in 2020, the French Alternative Energies and Atomic Energy Commission (CEA) has proposed a preliminary conceptual design of an electronuclear system for space applications aiming at fulfilling several requirements formulated by CNES. Among them, the most structuring were: the targeted electrical power (10 kW) for a period of at least 10 years, the need for robust technologies and the size and mass of the overall system that should be compatible with the Ariane 6 launcher fairing capacity.To fulfill these requirements, CEA has carried-out a preliminary design of a nuclear system, ECSPLORER, based on the main following features: a thermal spectrum core whose fuel is UO2 enriched to 19.75% in 235U with Zircaloy fuel cladding, a zirconium hydride (ZrH2) moderator and a beryllium reflector. The shield is made of tungsten and lithium hydride (LiH). A core cooling system made up of 150 steel heat pipes operating with a sodium-potassium alloy (NaK) has been pre-designed and a thermoelectric energy converter made up of SiGe thermo-elements generates electrical power. A hot carbon composite compact and monolithic radiator lined with titanium NaK heat pipes rejects the heat of the system.The so-called ECSPLORER pre-conceptual design elaborated in a constrained time period is nowadays under study again in order to further refine the operating point and the design options. In the framework of ECSPLORER design improvement, this lightning talk presents a methodology of an electronuclear system’s global design with simplified models for each coupled subsystems: reactor, cooling systems (heat pipes), converters, and radiator. On the one hand, there are some very precise and detailed models for each subsystem. For instance, there are computational fluid dynamics (CFD) models for thermal hydraulics in the state of the art. However, they take too much time for an optimization. On the other hand, some global models would not take into account the operation of each subsystems and their coupling, but only provide a rough insight to the project. This methodology’s aim is to answer the gap between those two kinds of models.It takes as input parameters the core’s geometry (fuel rod diameter, the heat pipe diameter, the pitch of the elementary hexagonal pattern) and the cold temperature of the thermal-electric converter. The outputs to optimize are the mass and size of the global system. The neutronics model is based on the Serpent neutron physics calculation code. Some constraints must be fulfilled, such as: geometry consistency of the core/heat pipe arrangement, core criticality, the operating limits of the heat pipes, the temperature of solid phase change of the Zircaloy, the temperature of decomposition of the moderator ZrH2 and the loss of nuclear reactivity over ten years without refueling. This leads to a design space of interest to be explored for reactor configurations. A parametric and a sensitivity analysis is performed within this space. An optimization is performed on several cores in order to highlight those minimizing the size and mass of the overall system. This methodology is applied on ECSPLORER and is tested on several cores to demonstrate the possibility of optimization of such cores