Observation of Gap Acceptance During Intersection Approach

This paper presents the results of a field test evaluating drivers’ decision making and gap acceptance for a left turn maneuver with opposite traffic; with a focus on the scenario where the turning vehicle is approaching the intersection. Twenty-three participants drove an instrumented vehicle ten times around an extended block turning left at four specific intersections. DGPS and radar data were combined to represent the trajectories of the turning vehicle and opposite traffic and to compute the gap between the turning vehicle and the lead vehicle of the on-coming traffic. The results cover the categorization of driver behavior based on the velocity profile while crossing the intersection. The velocity profile shows whether a driver stopped during the maneuver and the categories are defined based on where the driver stopped. The trajectories were then further sorted to account for the difference in speed profile or stopping location within one category. The characteristics of the accepted and rejected lags are presented and discussed, with an emphasis on turning drivers’ speed adaptation to the presence of an on-coming vehicle, and the presence of following traffic on a decision to stop. The conclusion of this study is that although valuable information was gathered during this field test, the data collection setup did not capture sufficiently the characteristic of the opposite traffic for a quantitative description of the effect of subsequent gaps on drivers’ decision to stop. Therefore, further data collection will be conducted on an instrumented intersection on a closed track

Intérêt du temps total de traite pour la sélection des vaches sur la vitesse de traite. I. – Le testage des taureaux

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On the Breeds of Cattle—Historic and Current Classifications

Classification of cattle breeds contributes to our understanding of the history of cattle and is essential for an effective conservation of genetic diversity. Here we review the various classifications over the last two centuries and compare the most recent classifications with genetic data. The classifications devised during the 19th to the late 20th century were in line with the Linnaean taxonomy and emphasized cranial or horn morphology. Subsequent classifications were based on coat color, geographic origin or molecular markers. Several theories were developed that linked breed characteristics either to a supposed ancestral aurochs subspecies or to a presumed ethnic origin. Most of the older classifications have now been discarded, but have introduced several Latin terms that are still in use. The most consistent classification was proposed in 1995 by Felius and emphasizes the geographic origin of breeds. This is largely in agreement with the breed clusters indicated by a biochemical and molecular genetic analysis, which reflect either groups of breeds with a common geographic origin or single breeds that have expanded by export and/or crossbreeding. We propose that this information is also relevant for managing the genetic diversity of cattl

La gestion des populations. La loi sur l’élevage et l’organisation générale de la sélection en France

National audiencePour obtenir de bons résultats en amélioration génétique, il faut des objectifs clairs, des méthodes éprouvées, des hommes compétents et une organisation assurant la cohérence des actions entreprises par chacun des partenaires. La Loi sur l’Elevage mise en place en France en 1966 a apporté aux élevages français le cadre correspondant qui est ici brièvement décrit. Le Département de Génétique Animale de l’INRA a, depuis le début, joué un rôle essentiel pour concevoir, mettre en place et assurer le suivi de toute cette organisation

Modifications physiologiques et spécifiques de la peau au cours de la grossesse

Les bouleversements hormonaux, immunologiques et métaboliques engendrés par l état gravide sont à l origine de nombreuses répercussions physiologiques et pathologiques sur le plan cutané.Les modifications physiologiques de la peau sont sources d inquiétude pour la femme enceinte du fait de la gêne fonctionnelle ou esthétique occasionnée. Elles peuvent toucher la pigmentation, le tissu conjonctif, le réseau vasculaire ou encore les annexes cutanées. Le pharmacien pourra alors informer, rassurer et conseiller ces femmes enceintes quant à la prévention et à la prise en charge de ces troubles bénins.Les modifications spécifiques que sont les dermatoses prurigineuses nécessitent une consultation médicale car, même si la plupart sont sans gravité pour la mère et l enfant, quelques unes requièrent un diagnostic précoce pour un suivi pluridisciplinaire. Le pharmacien pourra insister sur la prise en charge thérapeutique de ces dermatoses prurigineuses afin d améliorer l observance.LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

L'équilibre de la mamelle et la facilité de traite des vaches laitières

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Optimized control studies of a parallel hybrid electric vehicle

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references.Issued also on microfiche from Lange Micrographics.This thesis addresses the development of a control scheme to maximize automobile fuel economy and battery state-of-charge (SOC) while meeting exhaust emission standards for parallel hybrid electric vehicles, which are an alternative to conventional passenger vehicles. The principle components of the drive train are a small internal combustion engine and an electric motor, both of them applying torque directly to the drive shaft for propelling the vehicle. Each component of the parallel hybrid vehicle is modeled, and throttle angle, motor current and brake torque command chosen as the control inputs. A performance index describing the total fuel and battery charge used, as well as pollutants emitted over the federal drive cycle, is defined. The problem is to find the optimal control inputs, as a function of time, that minimize the performance index under the chosen drive cycle while satisfying lower and upper bounds on the controls as well as the torque command constraint, derived from the drive cycle speed that the vehicle must follow. The problem is formulated so that optimal control theory can be used by defining the Hamiltonian of the system and deriving the Euler-Lagrange equations. Four special cases for the control bounds which are of practical importance are considered. But, because of the complicated analytical derivatives, solving the general analytical problem is not tractable. The alternate approach that is chosen is a numerical optimization method that solves the constrained optimization problem using the Recursive Quadratic Programming Method.'To evaluate various control schemes, a set of selected performance measures are studied: only SOC performance, and balanced fuel and SOC performance. Simulations under the federal drive cycle show that we achieve the design objectives while getting better results than with a simple logic controller. The optimum control results suggest that the throttle should always be kept wide open for the SOC to be maximized. This should be accomplished with Buntin's logic controller and would allow us to keep his easy control implementation while improving his performance