Contrôle décentralisé d’un ensemble de dispositifs de chauffage électrique par commande à champ moyen

RÉSUMÉ Dans nombre de pays industrialisés, nous assistons à une transition technologique quant à la manière d’alimenter le réseau électrique. Les sources d’énergie fossiles comme le charbon, le pétrole ou la fission nucléaire sont peu à peu remplacées par les sources dites renouvelables que sont l’énergie solaire, éolienne ou encore hydro-électrique. Si les dispositifs photovoltaïques et éoliens permettent de réduire l’empreinte environnemen-tale de la génération d’électricité et jouissent d’une certaine flexibilité de déploiement, ils sou˙rent d’une forte variabilité de leur production dépendant de facteur environnementaux qu’il est impossible de maîtriser. Ceci peut impacter la stabilité du réseau en périodes de forte consommation, et force également les opérateurs à continuer de compter, au moins par-tiellement, sur des sources de génération à base fossile qui sont plus contrôlables. Une manière possible de lisser la demande en puissance lors des heures critiques est d’uti-liser l’énergie thermique contenue dans les habitations. En baissant la température interne des logements chau˙és par radiateurs électriques, il est possible de faire baisser la demande totale en énergie, surtout lors des mois d’hiver. A contrario, il est possible d’emmagasiner de l’énergie dans ces logements lors d’une période de surproduction. D’autre part, l’avènement de l’internet des objets et le développement des Smart Grids per-met d’obtenir une connaissance plus fine des variations de consommation du réseau de même qu’une plus grande communication entre le fournisseur et les utilisateurs. Nous présentons dans ce mémoire une série d’algorithmes de commande décentralisée sous la forme d’un jeu à champ moyen, pour un ensemble de chau˙e-espace domestiques permettant de répondre à une contrainte de puissance totale allouée à un tel ensemble.La contrainte de puissance est dictée par un agrégateur qui gère le parc de chau˙e-espace. Les algorithmes de commande sont conçus pour répondre au principe selon lequel chaque logement contribue à l’e˙ort selon ses moyens (au sens thermique) dans un souci d’équité. Ainsi, chaque module de chau˙age calcule lui-même l’e˙ort à fournir pour que le groupe entier respecte la contrainte globale de puissance. Conscients des propriétés de robustification que peut apporter la commande intégrale, nous y ajoutons une correction intégrale en temps réel assurant une robustesse du contrôle face aux éventuelles erreurs de modélisation du groupe commandé et de son environnement. Nous testons notre commande en simulant le comportement de populations de logements homogènes et hétérogènes lorsqu’ils sont soumis au contrôleur.----------ABSTRACT In a number of industrialized countries, we are witnessing a transition in the nature of the energy sources sustaining the electricity grid. Fossil energy sources such as coal, oil or nu-clear fission are gradually being replaced by so-called renewable sources such as solar, wind or hydroelectric power. While photovoltaic panels and wind turbines can help reduce the environmental footprint of electricity generation and can be reasonably deployed, they su˙er from a high variability in their production in that it depends on environmental factors that are impossible to control. This can impact the stability of the network during periods of high consumption and forces the utilities to continue to rely, at least partially on more controllable fossil based sources of generation. One possible way of smoothing the power demand during critical hours is to use the thermal energy contained in buildings and private homes. By lowering the internal temperature of homes heated by electric radiators, it is possible to lower the total energy demand, especially during the winter months. Conversely, it is possible to store energy in these dwellings during a period of renewable energy overproduction. On the other hand, the advent of the Internet of Things and the development of Smart Grids makes it possible to obtain a more precise knowledge of variations in network consumption and to increase communication between the power system operator and the users. We present in this master thesis a collection of possible decentralized controllers based on the formulation of a mean-field game involving a population of domestic space heaters which must meet a total power constraint allocation set by an aggregator. The proposed control scheme is designed to meet the principle according to which each dwelling contributes to the e˙ort according to its means (in the thermal sense) in a concern for equity. Thus, each local heating module calculates the e˙ort to be provided so that the whole group complies with the power constraint. Given the robustification properties brought about by integral controllers in general, We add an integral real-time correction to ensure the robustness of the control against possible mod-eling errors of the controlled group and its environment.We test our control algorithms by simulating the behaviour of homogeneous and heteroge-neous housing populations when submitted to the proposed control schemes

Intraoperative Blood Management Strategies for Patients Undergoing Noncardiac Surgery:The Ottawa Intraoperative Transfusion Consensus

IMPORTANCE: There is marked variability in red blood cell (RBC) transfusion during the intraoperative period. The development and implementation of existing clinical practice guidelines have been ineffective in reducing this variability.OBJECTIVE: To develop an internationally endorsed consensus statement about intraoperative transfusion in major noncardiac surgery.EVIDENCE REVIEW: A Delphi consensus survey technique with an anonymous 3-round iterative rating and feedback process was used. An expert panel of surgeons, anesthesiologists, and transfusion medicine specialists was recruited internationally. Statements were informed by extensive preparatory work, including a systematic reviews of intraoperative RBC guidelines and clinical trials, an interview study with patients to explore their perspectives about intraoperative transfusion, and interviews with physicians to understand the various behaviors that influence intraoperative transfusion decision-making. Thirty-eight statements were developed addressing (1) decision-making (interprofessional communication, clinical factors, procedural considerations, and audits), (2) restrictive transfusion strategies, (3) patient-centred considerations, and (4) research considerations (equipoise, outcomes, and protocol suspension). Panelists were asked to score statements on a 7-point Likert scale. Consensus was established with at least 75% agreement.FINDINGS: The 34-member expert panel (14 of 33 women [42%]) included 16 anesthesiologists, 11 surgeons, and 7 transfusion specialists; panelists had a median of 16 years' experience (range, 2-50 years), mainly in Canada (52% [17 of 33]), the US (27% [9 of 33]), and Europe (15% [5 of 33]). The panel recommended routine preoperative and intraoperative discussion between surgeons and anesthesiologists about intraoperative RBC transfusion as well as postoperative review of intraoperative transfusion events. Point-of-care hemoglobin testing devices were recommended for transfusion guidance, alongside an algorithmic transfusion protocol with a restrictive hemoglobin trigger; however, more research is needed to evaluate the use of restrictive triggers in the operating room. Expert consensus recommended a detailed preoperative consent discussion with patients of the risks and benefits of both anemia and RBC transfusion and routine disclosure of intraoperative transfusion. Postoperative morbidity and mortality were recommended as the most relevant outcomes associated with intraoperative RBC transfusion, and transfusion triggers of 70 and 90 g/L were considered acceptable hemoglobin triggers to evaluate restrictive and liberal transfusion strategies, respectively, in clinical trials.CONCLUSIONS AND RELEVANCE: This consensus statement offers internationally endorsed expert guidance across several key domains on intraoperative RBC transfusion practice for noncardiac surgical procedures for which patients are at medium or high risk of bleeding. Future work should emphasize knowledge translation strategies to integrate these recommendations into routine clinical practice and transfusion research activities.</p

Evaluating the feasibility of implementing a Telesleep pilot program using two-tiered external facilitation

Background: Obstructive sleep apnea (OSA) can negatively impact patients' health status and outcomes. Positive airway pressure (PAP) reverses airway obstruction and may reduce the risk of adverse outcomes. Remote monitoring of PAP (as opposed to in-person visits) may improve access to sleep medicine services. This study aimed to evaluate the feasibility of implementing a clinical program that delivers treatment for OSA through PAP remote monitoring using external facilitation as an implementation strategy. Methods: Participants included patients with OSA at a Veteran Affairs Medical Center (VAMC). PAP adherence and clinical disease severity on treatment (measured by the apnea hypopnea index [AHI]) were the preliminary effectiveness outcomes across two delivery models: usual care (in-person) and Telehealth nurse-delivered remote monitoring. We also assessed visit duration and travel distance. A prospective, mixed-methods evaluation examined the two-tiered external facilitation implementation strategy. Results: The pilot project included N = 52 usual care patients and N = 38 Telehealth nurse-delivered remote monitoring patients. PAP adherence and disease severity were similar across the delivery modalities. However, remote monitoring visits were 50% shorter than in-person visits and saved a mean of 72 miles of travel (median = 45.6, SD = 59.0, mode = 17.8, range 5.4-220). A total of 62 interviews were conducted during implementation with a purposive sample of 12 clinical staff involved in program implementation. Weekly external facilitation delivered to both front-line staff and supervisory physicians was necessary to ensure patient enrollment and treatment. Synchronized, "two-tiered" facilitation at the executive and coordinator levels proved crucial to developing the clinical and administrative infrastructure to support a PAP remote monitoring program and to overcome implementation barriers. Conclusions: Remote PAP monitoring had similar efficacy to in-person PAP services in this Veteran population. Although external facilitation is a widely-recognized implementation strategy in quality improvement projects, less is known about how multiple facilitators work together to help implement complex programs. Two-tiered facilitation offers a model well-suited to programs where innovations span disciplines, disrupt professional hierarchies (such as those between service chiefs, clinicians, and technicians) and bring together providers who do not know each other, yet must collaborate to improve access to care

Brans-Dicke corrections to the gravitational Sagnac effect

The {\it exact} formulation for the effect of the Brans-Dicke scalar field on the gravitational corrections to the Sagnac delay in the Jordan and Einstein frames is presented for the first time. The results completely agree with the known PPN factors in the weak field region. The calculations also reveal how the Brans-Dicke coupling parameter (appears in various correction terms for different types of source/observer orbits. A first order correction of roughly 2.83 x 10^{-1} fringe shift for visible light is introduced by the gravity-scalar field combination for Earth bound equatorial orbits. It is also demonstrated that the final predictions in the two frames do not differ. The effect of the scalar field on the geodetic and Lense-Thirring precession of a spherical gyroscope in circular polar orbit around the Earth is also computed with an eye towards the Stanford Gravity Probe-B experiment currently in progress. The feasibility of optical and matter-wave interferometric measurements is discussed briefly.Comment: 35 pages, 2 figures, pdf (from MSWord), accepted Physical Review D, January 2001. (revised from June 25, 2000 version

The measurement of bilingual abilities: central challenges

In this handbook chapter I analyse the concept of bilingual abilities. Bilinguals vary widely in what they can do with their languages or in the ways in which they use their languages on a daily basis. This means that there is a great deal of variability in what the term covers. While many researchers subscribe to the holistic view of bilingualism, in the academic literature bilinguals are still often described in negative terms as having a "deficit" in one or another subsystem of their languages. The key aim of this chapter is to identify what makes individuals with bilingual abilities unique speaker-hearers in their own right, avoiding the fractional view of bilingualism, and how these abilities can be measured

Antibacterial effect of calcium hydroxide combined with chlorhexidine on Enterococcus faecalis: a systematic review and meta-analysis

Objective: Enterococcus faecalis (E. faecalis) is the most frequently isolated strain in failed endodontic therapy cases since it is resistant to calcium hydroxide (CH). Whether a combination of CH and chlorhexidine (CHX) is more effective than CH alone against E. faecalis is a matter of controversy. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the literature. Material and Methods: A comprehensive search in PubMed, EMbase, EBSCOhost, The Cochrane Library, SciELO, and BBO databases, Clinical trials registers, Open Grey, and conference proceedings from the earliest available date to February 1, 2013 was carried out and the relevant articles were identified by two independent reviewers. Backward and forward search was performed and then inclusion and exclusion criteria were applied. The included studies were divided into "comparisons" according to the depth of sampling and dressing period of each medicament. Meta-analysis was performed using Stata software 10.0. The level of significance was set at 0.05. Results: Eighty-five studies were retrieved from databases and backward/forward searches. Fortyfive studies were considered as relevant (5 in vivo, 18 in vitro, 18 ex vivo, and 4 review articles). Nine studies were included for meta-analysis. Inter-observer agreement (Cohen kappa) was 0.93. The included studies were divided into 21 comparisons for meta-analysis. Chi-square test showed the comparisons were heterogeneous (p<0.001). Random effect model demonstrated no significant difference between CH/CHX mixture and CH alone in their effect on E. faecalis (p=0.115). Conclusions: According to the evidence available now, mixing CH with CHX does not significantly increase the antimicrobial activity of CH against E. faecalis. It appears that mixing CH with CHX does not improve its ex vivo antibacterial property as an intracanal medicament against E. faecalis. Further in vivo studies are necessary to confirm and correlate the findings of this study with the clinical outcomes