Multi-variable approach for the command of Canal de Provence Aix nord water supply subsystem, A

Presented during the USCID water management conference held on October 13-16, 2004 in Salt Lake City, Utah. The theme of the conference was "Water rights and related water supply issues."Includes bibliographical references.The Canal de Provence is fully user oriented. Water users can take the water freely without respecting neither rotation nor any sort of priority allocation. Its structure. consisting of main free flow canals and pressurized distribution networks. is well adapted to this strategy. The main canal must be able to face the regime variations coming from this kind of distribution. The current regulation conception first split the whole system into a series of assumed independent sub-systems. The multi-variable aspect is then taken into account by a coordination of the sub-systems adjustment, carrying the discharge correction from downstream to upstream. The Aix nord branch control presents interesting characteristics such as many different hydraulic entities (free surface canals. reservoirs. pumping stations) and operating constraints (levels in reservoirs. optimization of pumping costs). A real multi-variable approach will allow managing all gate and pump operations and all constraints at the same time. leading to a global optimisation of the whole system. The MIMO (Multi Input - Multi Output) model is established from transfer functions. the coefficients of which are deduced from the physical and geometrical characteristics of the system. A Linear Quadratic Regulator is computed and tested on a complete non-linear numerical model of the hydraulic system. The system to be controlled includes many discrete commands (pump operations) that are not managed by a classical optimal control. These commands are treated apart, leading to calculated perturbations that are introduced in the regulator.Proceedings sponsored by the U.S. Department of the Interior, Central Utah Project Completion Act Office and the U.S. Committee on Irrigation and Drainage

Influence of Canal Geometry and Dynamics on Controllability

This paper presents the results of the Task Committee on Canal Automation Algorithms with regard to the influence of canal properties on the controllability of irrigation canals. While the control provided by individual algorithms was not evaluated, studies were performed to illustrate inherent hydraulic limitations—the inability of canal pools to recover rapidly from disturbances or flow perturbations. Studies were performed in nondimensional form to develop a better understanding of how pool properties influence pool response. Three such studies were performed. First, nondimensional backwater curves were developed for a range of canal conditions. The second study involved the propagation of waves initiated at the upstream end of a canal pool, as this is influenced by downstream boundary conditions. Finally, the response of pools to downstream withdrawals was examined in terms of their sluggish recovery even when the correct flow change is applied upstream. These results will help in understanding how canal properties influence the ability of operators to effectively control a canal either manually or automatically, and should influence future design practices

Fast diffusion of a Lennard-Jones cluster on a crystalline surface

We present a Molecular Dynamics study of large Lennard-Jones clusters evolving on a crystalline surface. The static and the dynamic properties of the cluster are described. We find that large clusters can diffuse rapidly, as experimentally observed. The role of the mismatch between the lattice parameters of the cluster and the substrate is emphasized to explain the diffusion of the cluster. This diffusion can be described as a Brownian motion induced by the vibrationnal coupling to the substrate, a mechanism that has not been previously considered for cluster diffusion.Comment: latex, 5 pages with figure

Prise en charge de la grande précarité aux urgences du CHU d'Amiens

Introduction : Au cours de notre activité professionnelle, nous avons pu constater que de nombreux patients en situation de précarité sociale et médicale se présentaient dans le service des urgences du CHU d Amiens. Nous avons donc cherché à étudier les patients en situation de grande précarité, d abord en les identifiant puis en analysant leur prise en charge médico-sociale aux urgences. Méthode : Nous avons mené une étude rétrospective par revue de dossiers de 34 patients, âgés de plus de 17 ans, en situation de grande précarité. Ils ont été pris en charge au service d accueil des urgences du CHU d Amiens sur la période du 1/01/2008 au 31/12/2008. Résultats : Les patients en situation de grande précarité représentent 2% des passages aux urgences. Le profil-type est un homme, âgé de 44 ans, présentant une dépendance à l alcool, SDF, sans revenu minimum, sans emploi et sans couverture sociale, sans médecin traitant. Le motif de recours le plus fréquent est l ivresse aigüe. Il a été fait appel pour ces patients à des assistants sociaux, à l Unité Mobile d Alcoologie, à des psychiatres et à des neurologues. Des projets d avenir et de soins ont été mis en place pour 26 % d entre eux. Discussion : Nous devons mieux détecter ce type de patients en établissant des critères de grande précarité, ce qui permettrait de recourir de façon plus systématique à des avis spécialisés (assistants sociaux, psychiatres, alcoologues ). Nous proposons donc de renforcer la PASS et de mettre en place un carnet de consultations adapté pour envisager un suivi multidisciplinaire et médico-social de ce type de patients. Conclusion : Les patients en situation de grande précarité représentent un effectif important sur le nombre de passage aux urgences. Les médecins urgentistes assurent, par la force des choses, un suivi médical chez ce type de patient. Il serait souhaitable d établir des outils avec lesquels le médecin urgentiste pourrait les orienter dans des consultations multidisciplinaires.Introduction: Through our professional experiences, we noticed that many patients living in precarious social and medical conditions were visiting the emergency department of our University Hospital in Amiens, France. We therefore studied patients in major precarious situations, as a first step by identifying them and then by analyzing their medical and social support in the urgency unit. Method : We conducted a retrospective study including 34 over 17-years-old patients in the most precarious situations supported in the Emergency Unit of the CHU d Amiens on the period from 1 / 01 / 2008 to 31/12/2008. Results :Most precarious situations represent 2% of the total patients of the Emergency Unit of the Amiens CHU. The typical profile is a 44 years-old male, addicted to alcohol, homeless, unemployed, without health insurance, income and medical monitoring. The main reason of appeal is drunkenness. For these patients, social workers, alcoholism specialists, psychiatrists and neurologists were involved. Future plans and medical cares have been established for 26 % of them. Discussion : We need to identify such patients more efficiently by using high precariousness criteria which would allow a more systematic use of specialists (social workers, psychiatrist, alcohologist ...) by the emergency unit clinicians. We therefore propose to strengthen the PASS and create a suitable consultation program to consider a multi-disciplinary monitoring of these patients. Conclusion :High precarious patients represent a significant part of the activity of the emergency unit. By necessity, emergency physicians provide medical monitoring of these patients. Orientation criteria are needed to help doctors to contact a multidisciplinary consultation.AMIENS-BU Santé (800212102) / SudocSudocFranceF

Une analyse des déterminants de l'acceptation de la messagerie électronique par des personnels administratifs à l'université

The use and acceptance of the computing tools by end users is a necessary condition for their success. Davis' Technology Acceptance Model (TAM) offers a certain releavance in the study of the factors affecting e-mail use. In the present research, extensions of Davis' model are proposed, integrating phenomena of social norms and network externalities. Data are collected from 195 administrative people working in several French universities. The initial model formulated by Davis is supported. However, the results also show that the social influence is a major determinant of the acceptance of electronic mail. Finally, in agreement with the recent developments of the Innovation Diffusion Theory, the perceived level of diffusion has an indirect positive impact on acceptance.L'utilisation et l'acceptation des outils informatiques par les utilisateurs finals est une condition nécessaire de leur succès. Le modèle d'acceptation de la technologie (TAM) de Davis (1989) offre une certaine pertinence dans l'étude des déterminants de l'utilisation d'un outil comme la messagerie électronique. Dans cette recherche, des extensions du modèle initial sont proposées, intégrant les phénomènes d'influence sociale et d'externalités de réseau caractéristiques d'une technologie comme la mesagerie. Le modèle ainsi construit est testé auprès d'un échantillon de 195 personnels administratifs travaillant dans plusieurs universités françaises. Les résultats obtenus valident le modèle initial formulé par Davis mais montrent également que l'influence sociale est un déterminant majeur de l'acceptation de la messagerie électronique. Enfin, en accord avec les approches récentes traitant de la diffusion de l'innovation, il apparaît que le niveau de diffusion perçu a un impact positif indirect sur l'acceptation

Une analyse des déterminants de l\u27acceptation de la messagerie électronique par des personnels administratifs à l\u27université

The use and acceptance of the computing tools by end users is a necessary condition for their success. Davis\u27 Technology Acceptance Model (TAM) offers a certain releavance in the study of the factors affecting e-mail use. In the present research, extensions of Davis\u27 model are proposed, integrating phenomena of social norms and network externalities. Data are collected from 195 administrative people working in several French universities. The initial model formulated by Davis is supported. However, the results also show that the social influence is a major determinant of the acceptance of electronic mail. Finally, in agreement with the recent developments of the Innovation Diffusion Theory, the perceived level of diffusion has an indirect positive impact on acceptance

Quantitative Study of a Freely Cooling Granular Medium

We present a numerical study of a two-dimensional granular medium consisting of hard inelastic disks. The evolution of the medium throughout a cooling process is monitored. Two different types of instabilities (shearing and clustering instability) are found to develop in the system. The development of these instabilities is shown to be in qualitative and quantitative agreement with the predictions of linearized hydrodynamic theory.Nous présentons une étude d'un fluide granulaire modèle à deux dimensions composé de disques durs inélastiques. On s'intéresse à l'évolution du milieu pendant le processus de refroidissement. Dans un tel système, deux types d'instabilité peuvent apparaître spontanément. La caractérisation de leur croissance est quantitativement en accord avec la prédiction de l'hydrodynamique linéarisée

Journal de bord d’Elia, 2025

Deltour Jean-Pierre, Nougué Tiphaine, Vialle Coline. Journal de bord d’Elia, 2025. In: La Gazette des archives, n°240, 2015-4. Voyages extraordinairement numériques : 10 ans d'archivage électronique, et demain? sous la direction de Frédérique Fleisch et Anita Frieh. pp. 351-361