On Multi-Armed Bandit Designs for Dose-Finding Clinical Trials

We study the problem of finding the optimal dosage in early stage clinical trials through the multi-armed bandit lens. We advocate the use of the Thompson Sampling principle, a flexible algorithm that can accommodate different types of monotonicity assumptions on the toxicity and efficacy of the doses. For the simplest version of Thompson Sampling, based on a uniform prior distribution for each dose, we provide finite-time upper bounds on the number of sub-optimal dose selections, which is unprecedented for dose-finding algorithms. Through a large simulation study, we then show that variants of Thompson Sampling based on more sophisticated prior distributions outperform state-of-the-art dose identification algorithms in different types of dose-finding studies that occur in phase I or phase I/II trials

On Multi-Armed Bandit Designs for Dose-Finding Trials

International audienceWe study the problem of finding the optimal dosage in early stage clinical trials through the multi-armed bandit lens. We advocate the use of the Thompson Sampling principle, a flexible algorithm that can accommodate different types of monotonicity assumptions on the toxicity and efficacy of the doses. For the simplest version of Thompson Sampling, based on a uniform prior distribution for each dose, we provide finite-time upper bounds on the number of sub-optimal dose selections, which is unprecedented for dose-finding algorithms. Through a large simulation study, we then show that variants of Thompson Sampling based on more sophisticated prior distributions outperform state-of-the-art dose identification algorithms in different types of dose-finding studies that occur in phase I or phase I/II trials

L'étiologie de la hernie discale chez le chien

L'étiologie de la hernie discale est mal définie chez le chien comme chez l'homme. Elle correspond à l'association d'un facteur déterminant, la dégénérescence discale, à un ensemble de facteurs prédisposants et favorisants, dont les influences sont inégales et plus ou moins bien expliquées.NANTES-Ecole Nat.Vétérinaire (441092302) / SudocSudocFranceF

Les coopératives : « naturellement » plus responsables ? Le cas des coopératives du Languedoc-Roussillon

L’enjeu de ce travail est de se prononcer sur le profil plus ou moins responsable des coopératives par rapport aux autres entreprises, via l’analyse de leurs pratiques sociales, environnementales et sociétales. La dimension économique n’a volontairement pas fait l’objet d’analyse particulière au motif que les problématiques financières des coopératives sont supposées équivalentes à celles de toutes autres entreprises et ne constituent donc pas un critère différenciant. Pour ce faire, nous avons examiné les résultats d’une vaste enquête réalisée auprès de 322 entreprises agroalimentaires, dont 108 coopératives. Dans cet article,les auteures introduiront d’abord leurs objets d’analyse : les coopératives et le développement durable en précisant la situation languedocienne, ce qui les mènera à présenter les problématique et les hypothèses. Dans un second temps, les auteures présentent la méthodologie utilisée puis dans un troisième temps les résultats de leurs analyses

Innovation et développement durable dans les entreprises agroalimentaires du Languedoc-Roussillon

National audienceThere is not a lot of literature about relationship between innovation and sustainable development or, more precisely, CSR in companies. In this paper, we investigate these relationships, through the results of a survey of 322 food companies in the Languedoc-Roussillon. Both innovation and CSR in the food exhibit peculiarities that we specify. The survey included questions related to sustainable development in the company, in other words, CSR, others were more specifically oriented on innovation. The aim of this paper is to analyze the relationship between innovation and sustainable development, particularly to identify correlations between behavior and commitment to innovation in sustainable development, from "measures" of different actions performed, and analysis of innovations described

Modèles hydrauliques de la répartition des débits dans un croisement de quatre canaux en écoulement torrentiel

International audienceIntense rainfall on urban areas can generate severe flooding in the city, and if the conditions are right, the flow in the streets can be supercritical. The redistribution of the flow in street intersections determines the flow rates and water levels in the street network. We have investigated the flow that occurs when two supercritical flows collide in a 90° junction formed by streets of identical cross section. Several flow configurations within the intersection are possible, depending on the position of the hydraulic jumps that form in and upstream of the intersection. Previous work has identified three flow types, with Type II flows being further classified into three subregimes. Hydraulic models have been developed, based on the principles of the conservation of flow and momentum flux in the intersection, which predict the angles at which the jumps will form. These models can be used to determine the flow type that will occur. Moreover, additional models have been developed for computing the outflow discharge distribution. For Type I flows, it has not been possible to develop such a hydraulic model for the discharge distribution, but some data are provided for one configuration to indicate the influence of different parameters. For Type II and Type III flows, such models are developed, and their predictions agree with data obtained from the channel intersection facility at the Laboratory of Fluid Mechanics and Acoustics in Lyon.Les pluies intenses en zone urbaine peut générer des fortes inondations et l'écoulement peut être torrentiel dans les rues. La répartition de l'écoulement aux intersections détermine les niveaux d'eau dans les rues. Nous avons examiné l'écoulement qui se produit lorsque deux écoulements torrentiels se rencontrent dans un croisement à 90° formé de deux canaux de largeur identique. Plusieurs configurations sont possibles dans le croisement en fonction de la position des ressauts hydrauliques. Des travaux précédents avaient identifié trois types d'écoulements, le type II étant subdivisé en trois. Des modèles hydrauliques ont été développés en se fondant sur la conservation de la quantité de mouvement. Ces modèles déterminent le type d'écoulement et l'angle des ressauts. D'autres modèles permettent d'obtenir la répartition des débits pour les types II et III. Ces modèles ont été validés sur les expériences effectuées au LMFA (Lyon, France)

Influence de la topographie détaillée sur la modélisation d'un écoulement à travers un carrefour lors d'inondations en milieu urbain

International audienceFloods in dense urban areas propagate mainly through the streets, where the flow can be locally affected by elements of urban topography. This study aims at assessing the need of integrating detailed topography in numerical models when simulating urban floods. Acoustic Doppler Velocimetry and Large Scale Particle Image Velocimetry measurements in an experimental three branch junction representing a city crossroad are used to calibrate a numerical model solving the 2D shallow water equations. A constant eddy viscosity model proves to be accurate enough to calculate velocity fields, but such model requires a fine calibration against experimental data. Simulations run with this calibrated model are performed to study the impact of obstacles and sidewalks representative of urban areas. It is found that obstacles located in the downstream branch can highly perturb the velocities distribution downstream of the junction, whereas obstacles located in the upstream branches have less influence. The presence of sidewalks results in reduced flow section and higher velocities, but additional effects occur within and downstream of the junction. Simulations presented here show the need of considering detailed topography and elements of urban furniture if local velocities have to be represented

Patrimalp, Science of Heritage : perspectives on cultural artworks

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