681 research outputs found

    Teaching canal hydraulics and control using a computer game or a scale model canal

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    Irrigation is well known for being the largest water user, responsible for about 70% of the total amount of fresh water withdrawals. At the same time, this irrigation contributes for about 40% of the total food production and is vital for many regions of the world such as Western USA, Australia, Southern Europe, and many countries in Asia and Africa. Recent FAO figures indicate that, by the year 2030, food production will have to be increased by about 80% with only a possible increase of 12% of the water withdrawal. One unavoidable way of being able to reach this agenda is to reduce water demand by improving the hydraulic efficiency of irrigation schemes. Technical concepts involved in these modernization projects include open channel hydraulics and control engineering, which are usually taught in separate college curricula. Such projects are carried out in many places in the world, especially in developing countries, with the help of engineers, canal managers and decision makers. This paper presents two innovative teaching initiatives targeting this audience, with a view to present classical and modern techniques to improve the hydraulic efficiency of irrigation canals. One is based on a computer game using the SIC hydrodynamic model developed by Cemagref, France and the other one is based on a scaled canal located at the USBR Hydraulics Laboratory in Denver, Colorado, USA

    Identifying Hidden Communities of Interest with Topic-based Networks: A Case Study of the Community of Philosophers of Science (1930-2017)

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    Scientific networks are often investigated by means of citation analyses. Yet, interpretation of such networks in terms of semantic (and often disciplinary) content heavily depends on supplementary knowledge, notably about author research specialties. Similar situations arise more generally in many types of social networks whose semantic interpretation relies on supplementary information. Here, author community net-works are inferred from a topic model which provides direct insights into the semantic specificity of the identified “hidden communities of interest” (HCoI). Using a philosophy of science corpus of full-text articles (N=16,917), we investigate its underlying communities by measuring topic profile correlations be-tween authors. A diachronic perspective is built by modeling the research networks over different time-periods and mapping genealogical relationships be-tween communities. The results show a marked in-crease in philosophy of science communities over time and trace the progressive appearance of the specialization areas that structure the field today

    Connections with Coworkers on Social Network Sites: The Good, the Bad and the Ugly

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    A large number of individuals are connected with their coworkers on social network sites (SNS) that are personal and professional (e.g., Facebook), with consequences on workplace relationships. Drawing on SNS, social identity and boundary management literatures, we surveyed 202 employees and found that coworkers’ friendship-acts (e.g., liking, commenting) were positively associated with closeness to coworkers when coworkers were of the same age or older than the focal individual, and with organizational citizenship behaviors towards coworkers (OCBI) when coworkers were of the same age. Harmful behaviors from coworkers (e.g., disparaging comment) were negatively associated with closeness (but not with OBCI) when coworkers were older than the focal individual. In addition, preferences for the segmentation of one’s professional and personal roles moderated the relationship between coworkers’ friendship-acts and OCBI (but not closeness) such that the positive relationship was stronger when the focal individual had low (vs. high) preferences for segmentation

    SIC software

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    Presented at SCADA and related technologies for irrigation district modernization, II: a USCID water management conference held on June 6-9, 2007 in Denver, Colorado.Includes bibliographical references.An increasing number of irrigation canals are following modernization projects to improve their hydraulic efficiency, their quality of service to users and to face new operational constraints. The Gignac Canal has been specifically modernized in order to be used during certain periods of the year as an experimental platform for several partners. A SCADA system has been installed with display screens at the manager's office and a SCADA interface has been developed into the SIC hydrodynamic software allowing testing of any type of control algorithm. This testing can be done first on the SIC hydraulic simulation model, and then switched onto the real canal without any code rewriting or parameters change. This SIC SCADA interface is communicating with the SCADA system developed by DSA Company exchanging data forth and back through simple ASCII files. The features of this approach are described in this paper. This SCADA module is now included into the standard library of the SIC software. This tool has been intensively tested on the Gignac canal that will be used for illustration

    When are Social Network Sites Connections with Coworkers Beneficial? The Roles of Age Difference and Preferences for Segmentation between Work and Life

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    Individuals are increasingly connected with their coworkers on personal and professional social network sites (SNS) (e.g., Facebook), with consequences for workplace relationships. Drawing on SNS research and on social identity and boundary management theory, we surveyed 202 employees and found that coworkers’ friendship acts (e.g., liking, commenting) were positively associated with closeness to coworkers when coworkers were similar in age to or older than the respondent and were positively associated with organizational citizenship behaviors towards coworkers (OCBI) when coworkers were similar in age. Conversely, harmful behaviors from coworkers (e.g., disparaging comments) were negatively associated with closeness when coworkers were older than the respondent, and with OCBI when coworkers were older than the respondent and coworkers’ friendship acts were high. Preferences for work-life segmentation moderated the relationship between coworkers’ friendship acts and OCBI (but not closeness) such that the positive relationship was stronger when the respondent had low (vs. high) preferences for segmentation. We discuss the theoretical and practical implications of this study and propose an agenda for future research

    Desperately Seeking Sustainable Careers: Redesigning Professional Jobs for the Collaborative Crafting of Reduced-Load Work

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    Reduced-load (RL) work, a flexible customized form of part-time work in which a full-time job is redesigned to reduce the hours and the workload while taking a pay cut, can enable sustainable careers. Yet previous research suggests mixed results, with RL work facing implementation hurdles such as insufficient workload reduction, and stalled careers often adversely affecting women and caregivers. This study, therefore, focuses on the implementation of sustainable RL work and sheds light on key issues under-examined in prior studies: 1) the job redesign tactics that supervising managers implement to reduce workloads, and 2) shared responsibilities at the job and organizational levels. Drawing on the literature on sustainable careers, work redesign, and job crafting, we analyze 86 qualitative interviews with managers who experimented with RL work, HR experts, and executives in 20 organizations that were early adopters of RL work. We identify differentiating and integrating work redesign tactics that either reduced or reshuffled workloads. Next, we propose a three-stage process of collaborative crafting of RL work, in which employees, managers, and employers share responsibilities to strengthen the work redesign tactics and manage cultural expectations to support RL implementation. We provide implications for future research and practice

    H infinity observer for time-delay systems. Application to FDI for irrigation canals

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    This paper deals with the problem of fault detection and isolation for time-varying delayed systems. It consists to develop a H∞H_{\infty} observer that generates residuals sensitive to some faults and insensitive to others in order to detect and isolate actuator faults which can occur on the regulation gates of an irrigation canal. The observer design uses a simplified approximate model of the Saint-Venant equations and is formulated with delay-dependent Linear Matrix Inequality (LMI). Simulations done with a realistic model of a real canal show the effectiveness of the metho

    La protection du patient hospitalisé en psychiatrie : quelles spécificités ?

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    Il s’agit dans ce travail d'Ă©tudier la maniĂšre dont le droit positif protĂšge le patient hospitalisĂ© pour des soins psychiatriques par rapport Ă  un patient bĂ©nĂ©ficiant de soins somatiques. Il convient de prendre en compte le patient admis en soins libres et celui admis en soins sans consentement, et de montrer que son statut - mineur, majeur protĂ©gĂ©, personne ĂągĂ©e, dĂ©tenu, a une incidence sur sa protection. Il convient de se questionner sur le fait de savoir si le droit positif permet une garantie suffisante des droits du patient en soins psychiatriques. La protection du patient implique en effet un respect de ses droits fondamentaux tout au long de son hospitalisation. Or, en dĂ©pit de ce postulat, sa prise en charge peut se traduire par des restrictions justifiĂ©es par des motifs sĂ©curitaire ou thĂ©rapeutiques afin de le protĂ©ger de lui-mĂȘme, d'autrui et de garantir l'ordre public. DĂšs lors, cela conduit Ă  s’interroger sur l’existence de spĂ©cificitĂ©s dues Ă  son rĂ©gime de soins et Ă  son statut, et Ă  questionner la pertinence de ces particularitĂ©s. L’éventuelle reconnaissance de spĂ©cificitĂ©s liĂ©es Ă  la nature des soins ou au statut du patient conduit Ă  la recherche d’un Ă©quilibre nĂ©cessaire.It will be a question in this work of studying in what and if the right arrests in a particular way the patient in psychiatric care with regard to a patient benefiting from somatic care. It will be a question of taking into account as well the patient in free care as the patient in care without consent and of showing that he can exist a diversity of statuses(statutes) and it especially as he can also involve care to the prisoners, to the minors, to the protected adults whose legal situation by definition is not the same. What unit can we nevertheless release? It is necessary to become attached as well to mechanisms, to instruments of protection of the patient as to authorities in charge of its protection. We shall also wonder in the limits of this protection. The protection of the patient involves a respect for its fundamental rights - enumerated in a diversity of texts, obligations for the speakers and the responsibility of these, both towards the patient as towards the thirds and towards the civil society. This is still to know if it exists - and has to exist a specificity of the obligations pressing on the people asked to take care of these patients compared with people suffering other pathologies

    Microbial diversity and the “lower-limit” problem of biodiversity

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    Science is now studying biodiversity on a massive scale. These studies are occurring not just at the scale of larger plants and animals, but also at the scale of minute entities such as bacteria and viruses. This expansion has led to the development of a specific sub-field of “microbial diversity”. In this paper, I investigate how microbial diversity faces two of the classical issues encountered by the concept of “biodiversity”: the issues of defining the units of biodiversity and of choosing a mathematical measure of diversity. I also show that the extension of the scope of biodiversity to microbial entities such as viruses and many other not-clearly-alive entities raises yet another foundational issue: that of defining a “lower-limit” of biodiversity

    Data assimilation for hydraulic state estimation of a development project

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    International audienceAssurer la sĂ»retĂ© hydraulique sur les amĂ©nagements du RhĂŽne est la prioritĂ© pour la Compagnie Nationale du RhĂŽne. Cela signifie qu'il est indispensable de respecter les consignes d'exploitation sur les amĂ©nagements. Pour la rĂ©gulation automatique des amĂ©nagements, le calcul de la commande prĂ©dictive s'appuie sur les mesures en cote en certains points caractĂ©ristiques ainsi que sur les dĂ©bits aux ouvrages. De ce fait, lors de pannes de capteurs ou bien lors de forts phĂ©nomĂšnes transitoires (tels que des arrĂȘts ou dĂ©marrages de turbines), la rĂ©gulation est perturbĂ©e. Suite Ă  la prĂ©sente Ă©tude, la solution proposĂ©e pour corriger les observations et mettre Ă  jour les lignes d'eau intervenant dans le calcul des commandes, est la mise en place d'une mĂ©thode d'assimilation de donnĂ©es de type filtre de Kalman. Cette mĂ©thode est optimale dans le sens oĂč elle assure la minimisation de l'erreur d'estimation. Mais cela n'est pas suffisant pour certaines applications industrielles. C'est pourquoi les notions de dĂ©tectabilitĂ© et de convergence ont Ă©tĂ© approfondies. Cette Ă©tude a permis de dĂ©terminer des conditions suffisantes qui assurent une erreur de l'estimation convergente vers une moyenne nulle. Pour tester la mise en place d'une telle mĂ©thode, celle-ci a Ă©tĂ© implĂ©mentĂ©e sur l'outil de test industriel appelĂ© " plateforme de simulation ". Des exemples de scĂ©narios habituellement difficiles pour les rĂ©gulations automatiques, telles que la perte de capteur et l'arrĂȘt brutal d'une turbine sont prĂ©sentĂ©s. Ils permettent de dĂ©montrer l'apport de la solution proposĂ©e. / Ensure the safety of development projects of the RhĂŽne is the priority of the Compagnie Nationale du RhĂŽne. That means it is essential to respect the water levels at some set points along the river. To regulate its development projects, the computation of the predictive control is based on measurements at the characteristic points as well as flows at the hydraulic facilities. Thus, when failures of sensors occur or during strong transients (such as stopping or starting the turbines), the regulation process can be disturbed. Following this study, the new solution suggested to detect sensor defaults, to correct the observations and to update the water profiles involved in the calculation of control actions, is based on a data assimilation method (Kalman Filter). This method is optimal because it ensures minimizing the estimation error. But this property is not sufficient for our industrial application. This is why the notions of detectability and convergence have been studied into detail. This study has identified sufficient conditions that ensure the error of the estimate to converge towards a nil average. In order to test and validate such a method, it has been implemented into the industrial test tool called "simulation platform." Examples of usually difficult scenarios simulating a loss of sensor and an unexpected stopping of a turbine are presented in this document. It allows demonstrating the benefits of the presented solution
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