Os métodos de Aprendizagem por Reforço (AR) se mostram adequados para problemas de tomadas de decisões em diversos domínios por sua estrutura flexível e adaptável. Apesar de promissores, os métodos AR frequentemente tem seu campo de atuação prático restrito a problemas com espaço de estados de pequeno ou médio porte devido em muito à forma com que realizam a estimativa da função de avaliação. Nesta tese, uma nova abordagem de AR, denominada de Agente Topológico de Aprendizagem por Reforço (ATAR), inspirada em aprendizagem latente, é proposta para acelerar a aprendizagem por reforço através de um mecanismo alternativo de seleção dos pares estado-ação para atualização da estimativa da função de avaliação. A aprendizagem latente refere-se à aprendizagem animal que ocorre na ausência de reforço e que não é aparente até que um sinal de reforço seja percebido pelo agente. Este aprendizado faz com que um agente aprenda parcialmente uma tarefa mesmo antes que este receba qualquer sinal de reforço. Mapas Cognitivos são usualmente empregados para codificar a informação do ambiente em que o agente está imerso. Desta forma, o ATAR usa um mapa topológico, baseado em Mapas Auto-Organizáveis, para realizar as funções do mapa cognitivo e permitir um mecanismo simples de propagação das atualizações. O ATAR foi testado, em simulação, para planejamento de navegação de um robô móvel em ambientes inicialmente desconhecidos e não-estruturados. Comparações com outros seis algoritmos AR avaliaram comparativamente o desempenho do agente proposto na navegação. Os resultados obtidos são promissores e comparáveis com os algoritmos AR mais rápidos testados, alcançando em alguns ensaios desempenho superior aos dos demais algoritmos - principalmente nas simulações que consideram situações observadas em ambientes não-estruturados. Três características do ATAR original foram alteradas para tornar ainda mais viável sua aplicação prática: (i) mudanças no mapa topológico para reduzir o número de vértices, (ii) mudança na heurística usada na seleção das ações do agente e (iii) variações na estratégia de exploração do ATAR. Do ponto (i), foi proposto e implementado um novo mapa topológico, o Mapa Topológico Incremental Classificador MTIC, que a partir da classificação dos estados do ambiente gera os vértices de uma triangularização de Watson. O ponto (ii) criou um método aplicável a outros problemas de planejamento de trajetória em grafos denominado de Melhoria das trajetórias por detecção de ponto interior. O terceiro estudou estratégias direcionadas de exploração como uma opção para acelerar o aprendizado do ATAR. / Reinforcement Learning (RL) methods have shown to be a good choice for decision-making problems due to their flexible and adaptive characteristics. Despite such promising features, RL methods often have their practical application restricted to small or medium size (at state, or state-action, space) problems mainly because of their standard strategies for value function estimation. In this thesis, a new RL approach, called \"Topological Reinforcement Learning Agent\" - TRLA, is proposed to accelerate learning through an alternative mechanism to update the state-action value function. TRLA is inspired in latent learning, which refers to animal learning that occurs in the absence of reinforcements and that is not visible until an environmental reinforcement is perceived. This concept considers that part of a task can be learned even before the agent receives any indication of how to perform such a task. Cognitive Maps are usually used to encode information about the environment where the agent is immersed. Thus, the TRLA uses a topological map, based on Self-Organized Maps, to implement cognitive map functions and permit a new simple mechanism to execute the propagation of state-action updates. The chosen problem to test TRLA is the simulation of a mobile robot navigation in some initially unknown and unstructured environments. Performance comparisons of the TRLA with six other RL algorithms were carried out to the execution of the navigation task. The obtained results are very promising and comparable with some of faster RL algorithms simulated. In some experiments, the TRLA\'s performance overcomes the others especially in simulations with unstructured environments. Three characteristics of the original TRLA were modified to make it more suitable for real implementations: (i) changes in the topological map construction to reduce the vertices number, (ii) changes in the agents heuristic for action selection, and (iii) variations on the TRLAs strategy for exploration of the state-action space. In (i), a new procedure to construct topological maps was proposed and implemented, the Incremental Classifier Topological Map ICTM, which generates the vertices for a Watsons triangulation from the classification of the input states. In (ii), it was proposed a method to optimize trajectory planning problems based on graphs, denoted \"trajectory improvement from inner point detection\". The third point considers directed exploration strategies as an option for TRLA\'s learning acceleration.

Ce travail concerne une étude numérique des performances thermiques d’un séchoir- serre équipé d’une unité de stockage de chaleur solaire dans des matériaux à changement de phase (MCPs). L'unité de stockage de chaleur solaire, placée sous le sol de la serre, est composée d’une couche de MCPs (paraffine) disposée entre une plaque en acier et une couche de béton. L'écoulement de l'air asséchant se déroule par convection forcée et le produit disposé sur les claies du séchoir est la banane (Bananas Musa ABB CV. Kluai "Namwa"). Les équations de transfert de chaleur dans la serre, basées sur la méthode nodale, sont déduites d'un bilan thermique établi pour les différents composants du séchoir-serre. Les transferts de chaleur dans les couches de MCPs et de béton sont décrits respectivement par le modèle enthalpique et l'équation de la conduction. Le modèle de cinétique de séchage de la banane est celui d’Oswin modifié. Les équations de transferts sont résolues par une méthode implicite aux différences finies et les algorithmes de Gauss et de Thomas. Nous analysons l'influence du débit d'air asséchant et de l’irradiation solaire sur les distributions spatio-temporelles des températures des composants de la serre et de l'unité de stockage, la durée de séchage, les efficacités thermiques du séchoir-serre et de l'unité de stockage d'énergie. Cette modélisation est complétée par des simulations du fonctionnement du séchoir serre-unité de stockage de chaleur en utilisant la notion de journée type et les données météorologiques de Nakorn Pathom (Thaïlande) et par une analyse de faisabilité technico-économique. Les résultats montrent notamment que l’unité de stockage de chaleur contribue à la réduction de la durée de séchage et augmente les performances thermiques du séchoir et l’unité de stockage. / This work is about a numerical study of the thermal behavior of a solar greenhouse dryer and a heat storage unit in phase change materials (PCMs). The heat storage unit containing of PCMs (paraffin) is disposed between a metal plate and a concrete layer and placed under the floor of the greenhouse. The air drying flows along the greenhouse by forced convection and the products placed on the dryer's rack is bananas (Bananas Musa ABB CV Kluai "Namwa"). The heat transfer equations in the greenhouse are based on the nodal method and deduced from a thermal balance on the different components of the solar greenhouse dryer. The heat transfers in the PCMs and the concrete slab are described by the enthalpy method and the conduction equation, respectively. The banana drying kinetic is described by the model modified of Oswin. Transfer equations are solved using an implicit finite difference method associated to Gauss and Thomas algorithms. We analyze the effects of the air drying volumetric flow rate and the solar irradiance on the temperature distribution of the greenhouse dryer and the heat storage unit, the drying time, the solar greenhouse dryer and heat storage unit efficiencies. This modeling is complemented by simulations of the solar greenhouse dryer with the heat storage unit using the day type and the meteorological data of Nakorn Pathom (Thailand) and by an economic analysis. The results show that the heat storage unit provides the reduction of the drying time and increases the thermal performances of the solar greenhouse dryer and the heat storage unit.

A présent, les bâtiments résidentiels et commerciaux sont en phase de devenir le secteur le plus consommateur d’énergie dans de nombreux pays, comme par exemple en France. Diverses recherches ont été menées de manière à réduire la consommation énergétiques des bâtiments et augmenter leur confort thermique. Parmi tous les différentes approches, la technologie du stockage de chaleur latent se distingue par une très bonne capacité à stocker la chaleur afin de réduire les écarts entre la disponibilité et la demande d’énergie. Dans le cadre de l’un de nos projets, nous avons l’intention d’intégrer au design des murs des bâtiments un type de brique transparente remplie de matériaux à changement de phase (MCP). Les MCP à l’intérieur de la brique sont soumis à des changements de phase liquide-solide. Cette thèse s’attaque à la problématique du processus de fusion au sein de la brique. Au cours de cette thèse, une méthode expérimentale non-intrusive a été développée afin d’améliorer les techniques expérimentales existantes. La vélocimétrie des images des particules (VIP) et la fluorescence induite par laser (FIL) ont été couplées pour étudier la convection naturelle et la distribution de la température. Puisqu’aucun thermocouple n’a été inséré au sein de la brique, le processus de la fusion a été considéré sans perturbation. Les résultats montrent que cette conception expérimentale a un avenir prometteur, même si elle reste à améliorer. Par la suite, nous présentons deux simulations numériques. Ces simulations se fondent sur la méthode de Boltzmann sur réseau à temps de relaxation multiple (LBM MRT), employée pour résoudre le champ de vitesse, et sur la méthode de différences finies, pour obtenir la distribution de la température. La méthode d’enthalpie a quant à elle été utilisée pour simuler le changement de phase. Les simulations en deux dimensions et trois dimensions ont toutes deux été réalisées avec succès. Point important, ces simulations numériques ont été développées en langage C pour tourner spécifiquement sur un processeur graphique (GPU), afin d’augmenter l’efficacité de la simulation en profitant de la capacité de calcul d’un GPU. Les résultats des simulations concordent bien avec les résultats de nos expériences et avec les résultats analytiques publiés. / The domestic and commercial buildings are currently becoming the major sector that consumes the biggest share of the energy in many countries, for example in France. Various researches have been carried out in order to reduce the energy consumption and increase the thermal comfort of builds. Among all the possible approaches, the latent heat storage technology distinguishes itself because of its excellent heat storage ability which can be used to efficiently reduce the discrepancy between the energy consumption and supply. In one of our project, we intend to integrate a type of transparent brick filled with phase change material (PCM) into the buildings' wall design. The PCM inside the brick undergoes the solid-liquid phase change. This dissertation addresses the important issues of the melting process inside the brick. In this dissertation, a non-intrusive experimental method was proposed to improve the existing experiment technique. The particle image velocimetry (PIV) and the laser-induced fluorescence (LIF) were coupled to investigate the natural convection and the temperature distribution. Because there was no thermocouple installed inside the brick, the melting process was thus considered to be less impacted. The results showed that this experimental design has a promising future, yet still needs to be improved. Two sets of efficient numerical simulations were also presented in this dissertation. The simulations were based on the thermal lattice Boltzmann method (TLBM), where the natural convection got solved by the LBM and the temperature equation was solved by the finite difference scheme. The enthalpy method was employed to simulate the phase change. Both the 2-dimensional and 3-dimensional configurations were successfully simulated. Moreover, the simulation programs were specifically developed - using the C language - to be run on the graphic processing unit (GPU), in order to increase the simulation efficiency. The simulation results demonstrated a good agreement with our experimental results and the published analytical results.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Bovine herpesvirus type 5 (BHV-5) is a major etiologic agent of meningo-encephalitis in cattle and establishes lifelong latent infection in trigeminal ganglia and also in other areas of the brain. Colonization of deep areas of the brain with latent viral DNA may have important implications on the pathogenesis of BHV-5 neurological infection upon reactivation. In this study, we investigated the distribution of BHV-5 DNA in the brain of experimentally infected rabbits a laboratory model for BHV-5 infection - prior and subsequently to virus reactivation, using a nested PCR for the glycoprotein B gene. Eighteen rabbits inoculated intranasally with a Brazilian BHV-5 isolate were divided in two groups: group A rabbits (n=8) were euthanized 60 days post-inoculation (pi) for tissue collection; group B (n=7) were submitted to dexamethasone administration at day 60pi for reactivation of latent infection and euthanized for tissue collection 60 days later. To compare, we used two groups of BHV-1-infected rabbits (C, n=3 and D, n=3), each group being submitted to one of the above treatments, respectively. In group A rabbits, viral DNA was consistently detected in trigeminal ganglia (8/8), frequently in cerebellum (6/8), anterior cortex, pons medulla (3/8) and only occasionally in thalamus (2/8), ventro-lateral, dorsal and posterior cortices, midbrain (1/8). In rabbits previously submitted to virus reactivation, viral DNA showed a broader distribution, being detected more frequently besides the TG (7/7) - in ventro-lateral (6/7) and posterior cortices (5/7), pons-medulla and thalamus (4/7) and midbrain (3/7). In contrast, rabbits inoculated with BHV-1 harbored latent viral DNA in a few tissues in addition to TG and did not show significant changes in distribution of viral DNA post-reactivation. These results demonstrate that latency by BHV-5 DNA and not BHV-1 DNA may be established in several areas of the brain of experimentally infected rabbits. Further, dexamethasone-induced virus reactivation is followed by a wider distribution of latent viral DNA, probably due to virus dissemination from the original sites. Thus, it is reasonable to speculate that reactivation of latent infection from deep areas of the brain may contribute to the recrudescence of neurological disease frequently observed upon reactivation of latent BHV-5 infection. / O herpesvírus bovino tipo 5 (BHV-5) é um importante agente etiológico de meningoencefalite em bovinos e estabelece infecção latente em seus hospedeiros, principalmente nos gânglios dos nervos sensoriais. No entanto, a colonização de áreas profundas do cérebro com DNA viral pode ter implicações importantes na patogenia da infecção pelo BHV-5 após a reativação da infecção latente. Neste estudo, foi investigada a distribuição do DNA do BHV-5 no cérebro de coelhos infectados experimentalmente, antes e após a reativação da infecção latente, utilizando um nested-PCR para uma seqüência do gene da glicoproteína B. Dezoito coelhos infectados pela via intranasal com um isolado brasileiro de BHV-5 foram divididos em dois grupos: coelhos do grupo A (n=8) foram submetidos a eutanásia 60 dias pós inoculação (pi) para a coleta de tecidos; animais do grupo B (n=7) foram submetidos a administração de dexametasona no dia 60 pi. Para comparação foram utilizados dois grupos de coelhos inoculados com o BHV-1 (C, n=3 e D, n=3), cada grupo sendo submetido a um dos tratamentos acima, respectivamente. Nos animais do grupo A, o DNA viral foi consistentemente detectado no gânglio trigêmeo (8/8), freqüentemente no cerebelo (6/8), com menor freqüência na ponte e córtex anterior (3/8) e ocasionalmente no tálamo (2/8) e córtices ventro-lateral, dorso-lateral e posterior, pedúnculo cerebral e tálamo (1/8). Nos animais previamente submetidos à reativação, a distribuição do DNA viral foi mais ampla, sendo detectado mais consistentemente, além do TG (7/7), nos córtices ventro-lateral (6/7), e posterior (5/7), ponte e tálamo (4/7) e menos freqüentemente no pedúnculo cerebral (3/7). Em contrapartida, os animais inoculados com o BHV-1 apresentaram o DNA viral latente em poucos tecidos além do TG, e não apresentaram alterações importantes na distribuição do DNA viral após a reativação. Esses resultados demonstraram que o DNA latente do BHV-5 - e não o do BHV-1 - pode estar presente em várias áreas do cérebro de coelhos infectados experimentalmente. A reativação induzida por dexametasona resulta na reativação viral e provavelmente na colonização de áreas adicionais no cérebro. Com base nesses resultados pode-se especular que a reativação do DNA viral latente nestas regiões pode contribuir para a recrudescência de doença neurológica observada após a reativação da infecção latente pelo BHV-5.

Com a evolução da informática, diferentes meios de comunicação passaram a explorar a Web como um meio de divulgação de suas informações. Diferentes fontes de informações, diferentes estilos de escrita e a curiosidade nata do ser humano despertam o interesse de leitores por conhecer mais de um relato sobre um mesmo tema. Para que a leitura de diferentes relatos com conteúdo similar seja possível, leitores precisam procurar, ler e analisar informações fornecidas por diferentes fontes de informação. Essa atividade, além de exigir grande investimento de tempo, sobrecarrega cognitivamente usuários. Faz parte das pesquisas da área de Hipermídia investigar mecanismos que apóiem usuários no processo de identificação de informações em repositórios homogêneos, sejam eles disponibilizados na Web ou não. No contexto desta tese, repositórios com informações de conteúdo homogêneo são aqueles cujas informações tratam do mesmo assunto. Esta tese tem por objetivo investigar a especificação, a instanciação e a experimentação de um arcabouço para apoiar a tarefa de criação automática de ligações hipertexto entre repositórios homogêneos. O arcabouço proposto, denominado CARe (Criação Automática de Relacionamentos), é representado por um conjunto de classes que realizam a coleta de informações a serem relacionadas e que processam essas informações para a geração de índices. Esses índices são relacionados e utilizados na criação automática de ligações hipertexto entre a informação original. A definição do arcabouço se deu após uma fase de análise de domínio na qual foram identificados requisitos e construídos componentes de software. Nessa fase, vários protótipos também foram construídos de modo iterativo / With the evolution of the Internet, distinct communication media have focused on the Web as a channel of information publishing. An immediate consequence is an abundance of sources of information and writing styles in the Web. This effect, combining with the inherent curiosity of human beings, has led Web users to look for more than a single article about a same subject. To gain access to separate on a same subject, readers need to search, read and analyze information provided by different sources of information. Besides consuming a great amount of time, that activity imposes a cognitive overhead to users. Several hypermedia researches have investigated mechanisms for supporting users during the process of identifying information on homogeneous repositories, available or not on the Web. In this thesis, homogeneous repositories are those containing information that describes a same subject. This thesis aims at investigating the specification and the construction of a framework intended to support the task of automatic creation of hypertext links between homogeneous repositories. The framework proposed, called CARe (Automatic Creation of Relationships), is composed of a set of classes, methods and relationships that gather information to be related, and also process that information for generating an index. Those indexes are related and used in the automatic creation of hypertext links among distinct excerpts of original information. The framework was defined based on a phase of domain analysis in which requirements were identified and software components were built. In that same phase several prototypes were developed in an iterative prototyping

La crise de la COVID-19 a provoqué des bouleversements majeurs dans la vie des populations du monde entier et a suscité des réactions sociales importantes. La propagation du virus contagieux de la COVID-19 a été rapidement suivie d’une « épidémie » d’explications et de discours tentant de donner un sens à la crise. Lorsqu’un événement dévastateur se produit, les gens se demandent ce qui se passe et ce que cela signifie. Le premier but de cette recherche est de suivre l’évolution de la dynamique du blâme et de la désignation de boucs émissaires au fur et à mesure que la pandémie de COVID-19 se déroule. Le deuxième but de cette recherche est d’évaluer l’intérêt d’utiliser l’Allocation de Dirichlet latente (ADL), un modèle de mélange/classe latente génératif bayésien, dans l’analyse de questions ouvertes. Les données ont été recueillies auprès d’un échantillon représentatif de 3617 Canadiens selon un devis de recherche longitudinal intensif (avec 12 temps de mesure). Neuf thématiques ont été identifiées, dont six sont récurrentes à différents temps de mesure. Les résultats indiquent que, durant les premiers mois de la pandémie, les Canadiens blâment majoritairement les collectivités distantes, telles que la Chine et les marchés aux animaux vivants (wet markets). Au fil du temps, ils blâment de plus en plus les collectivités locales, tels que les individus qui ne respectent pas les mesures sanitaires. Cette recherche met en évidence le rôle de la proximité géographique et de l’évaluation du risque dans la manière dont le public perçoit la pandémie. / The COVID-19 crisis has caused major disruptions in the lives of populations around the globe and provoked important social responses. The spread of the contagious COVID-19 virus was quickly followed by an outbreak of explanations and discourses trying to make sense of the crisis. When devastating events occur, people ask themselves what happened, why the event happened and what it means. The first goal of this paper is to track the changing dynamics of blame attribution and scapegoating as the COVID-19 pandemic unfolds. The second goal of this paper is to evaluate the relevance of LDA (Latent Dirichlet Allocation), a Bayesian generative mixture/latent class model, to analyze open-ended survey responses. Data was collected from a representative sample of 3,617 Canadians following an intensive longitudinal research design (with 12 waves). Nine topics were identified, six of which were recurring. Canadians mostly blame distant collectives in the early months of the pandemic, especially China and wet markets. Over time, they increasingly blame local collectives, such as individuals who do not comply with sanitary measures. This study highlights the role of geographic proximity and perceived risk in shaping public perceptions of the pandemic.

La prise en compte du cadrage fait par les influenceurs de la droite radicale et du contenu de leur discours reste peu explorée. Ces contenus sont particulièrement préoccupants lorsqu’ils sont produits par des « influenceurs » qui auraient non seulement un pouvoir social sur leurs nombreux adeptes engagés, mais qui susciteraient aussi une opposition souvent virulente envers les autorités. Certains affirment que la recherche a manqué d’études empiriques systématiques sur le sujet et l’étude de la variation de cadre serait une piste intéressante pour de futures recherches (Benford 1997). Il y a donc un besoin pressant de développer une compréhension rigoureuse de la façon dont des crises mondiales peuvent changer la façon dont certains influenceurs de la droite radicale cadrent leurs discours. En utilisant des données originales sur cinq influenceurs de la droite radicale au Québec sur la plateforme Twitter de janvier 2020 à avril 2022, nous relevons d’abord les sujets prédominants dans le discours des influenceurs de la droite radicale. Grâce à une analyse thématique par LDA, nous confirmons que sept sujets dominent le discours des influenceurs de la droite radicale durant la pandémie de COVID-19, soit les élites, la gestion de crise, les médias, la fausse pandémie, la conspiration, le gouvernement et la liberté. Deuxièmement, nous montrons que la crise sanitaire de COVID-19 a poussé les influenceurs de la droite radicale à changer leur discours et à adopter trois « cadres de crise » qui présentent la COVID-19 comme directement liée aux concepts de gouvernance, de conspiration et de liberté. / The framing done by radical right influencers and the content of their discourse remain underexplored. Such content is of serious concern when it is produced by "influencers" who would not only have social power over their many committed followers, but also would generate often virulent opposition to the authorities. Some argue that research has lacked systematic empirical studies on the topic and the study of frame variation would be an interesting avenue for future research (Benford 1997). There is thus a pressing need to develop a rigorous understanding of how global crises can change the way some radical right-wing influencers frame their discourse. Using original data about five radical right influencers in Quebec on the Twitter platform from January 2020 to April 2022, we first identify the predominant topics in radical right influencers' discourse. Through a thematic analysis by LDA, we confirm that six topics dominate the discourse of radical right influencers during the pandemic of COVID-19: elites, crisis management, media, fake pandemic, conspiracy, and freedom. Second, we show that the COVID-19 health crisis pushed radical right influencers to change their discourse and adopt three "crisis frames" that present COVID-19 as directly related to the concepts of conspiracy, governance, and freedom.

[EN] This PhD Thesis has been developed at the Instituto de Ingeniería Energética of the Universitat Politècnica de València, within the group SIMES dedicated to the research on thermal systems. The group SIMES has developed a research project on latent heat storage of thermal energy in which different materials have been studied in order to analyse their performance as phase change materials for the latent heat storage. The aim of this thesis is the development of two models in MATLAB for the simulation of the performance of latent heat thermal energy storage systems in their processes of charge and discharge, in particular for cold storage. The development of these models allows for a deep understanding of the mechanisms that are governing the performance of this systems. The need of two different models is due to the different physical nature of the studied phase change materials: water and paraffin RT8. Each material determines a different performance in the phase change process. While water presents two differentiated phases and separated by an interphase, the paraffin RT8 experiences the solid-liquid phase change in a temperature interval, within a mushy state which is not completely liquid nor solid. Consequently, it was necessary to develop of a moving-boundary model for the simulation of the tanks with ice-water, and another enthalpy model for the simulation of tanks with paraffin RT8 as PCM. Finally, the developed models have helped analyse the performance of both materials in different latent heat storage applications, and determine the suitable system for each case. The models are useful also as a tool for the design and sizing of the system, to study their operation and carry out techno-economical analysis of different configurations. / [ES] La presente tesis doctoral ha sido desarrollada en el Instituto de Ingeniería Energética de la Universitat Politècnica de València, dentro del grupo SIMES dedicado a la investigación de sistemas térmicos. El grupo SIMES ha desarrollado un proyecto de investigación de almacenamiento latente de energía térmica en el que se han estudiado diferentes materiales para analizar su comportamiento como materiales de cambio de fase para el almacenamiento latente. El objetivo principal de esta tesis es el desarrollo de dos modelos en MATLAB para la simulación del comportamiento de depósitos de almacenamiento latente de energía térmica en sus procesos de carga y descarga, concretamente para la aplicación de almacenamiento de frío. El desarrollo de estos modelos permite conocer en profundidad los mecanismos que determinan el comportamiento de estos sistemas. El hecho de desarrollar dos modelos distintos se debe a la distinta naturaleza física de los materiales de cambio de fase estudiados: el agua y la parafina RT8. Dicha naturaleza determina un comportamiento distinto en sus procesos de cambio de fase. Mientras el agua presenta dos fases diferenciadas y separadas por una interfase, la parafina RT8 experimenta el cambio de fase sólido-líquido en un intervalo de temperatura, en el que el estado del material es un estado esponjoso que no resulta ser completamente sólido ni líquido. Por este motivo ha sido necesario el desarrollo de un modelo de frontera móvil para la simulación de los depósitos con agua-hielo, y otro modelo entálpico para la simulación de depósitos con la parafina RT8 como PCM. Finalmente, los modelos desarrollados permiten analizar el comportamiento de ambos materiales como almacenamiento latente en distintas aplicaciones, y determinar el sistema más adecuado en cada caso. Los modelos sirven también de herramienta de diseño y dimensionamiento del sistema, de su operación y para la realización de un estudio energético-económico y comparación de los resultados obtenidos con ambas configuraciones. / [CA] La present tesis doctoral ha sigut desenvolupada a l'Instituto de Ingeniería Energética de la Universitat Politècnica de València, dins del grup SIMES dedicat a la investigació de sistemes tèrmics. El grup SIMES ha desenvolupat un projecte de investigació d'emmagatzematge latent d'energia tèrmica en què s'han estudiat diferents materials per a analitzar el seu comportament com a materials de canvi de fase per a l'emmagatzematge latent. L'objectiu principal d'aquesta tesis és el desenvolupament de dos models en MATLAB per a la simulació del comportament de dipòsits d'emmagatzematge latent d'energia tèrmica en els seus processos de càrrega i descàrrega, concretament per a l'aplicació d'emmagatzematge de fred. El desenvolupament d'aquests models permet conèixer en profunditat els mecanismes que determinen el comportament d'aquests sistemes. El fet de desenvolupar dos models distints és degut a la distinta naturalesa física dels materials de canvi de fase estudiats: l'aigua i la parafina RT8. Aquesta naturalesa determina un comportament distint en els seus processos de canvi de fase. Mentre l'aigua presenta dos fases diferenciades i separades per una interfase, la parafina RT8 experimenta el canvi de fase sòlid-líquid en un interval de temperatura, en el que l'estat del material és un estat esponjós que no resulta ser completament sòlid ni líquid. Per aquest motiu ha sigut necessari el desenvolupament d'un model de frontera mòbil per a la simulació dels dipòsits amb aigua-gel, i un altre model entàlpic per a la simulació de dipòsits amb la parafina RT8 com a PCM. Finalment, els models desenvolupats permeten analitzar el comportament d'ambdós materials com a emmagatzematge latent en distintes aplicacions, i determinar el sistema més adequat en cada cas. Els models serveixen també de ferramenta de disseny i dimensionament del sistema, de la seua operació i per a la realització d'un estudi energètic-econòmic i comparació dels resultats obtinguts amb ambdues configuracions. / Biosca Taronger, X. (2016). MODELADO Y ANÁLISIS DE UN DEPÓSITO DE ALMACENAMIENTO LATENTE DE ENERGÍA TÉRMICA CON INTERCAMBIADOR DE TIPO SERPENTÍN [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62163

Dans les démocraties occidentales, la notion d’opinion publique occupe une place importante dans l’action des politiciens et le discours des médias. Elle y renvoie généralement à la somme des opinions individuelles des citoyens, aux résultats de sondages. Or, les limites de l’opinion publique ainsi conceptualisée apparaissent de plus en plus clairement aux chercheurs en sciences sociales, et cela jette un doute sur sa valeur comme guide des politiques publiques. Pour mieux comprendre la place de l’opinion publique dans le processus démocratique québécois, nous avons cherché à connaître les conceptions qu’en ont certains acteurs-clés : les chroniqueurs politiques et éditorialistes francophones du Québec. Au moyen d’entrevues, nous avons documenté leurs « théories profanes » à ce sujet, c’est à dire leurs façons de voir l’opinion publique et sa place dans le processus démocratique. L’exercice nous apprend que ces « commentateurs habituels » distinguent plusieurs formes d’opinion publique, de valeur inégale. Celle qui revêt le plus d’intérêt pour eux est une « opinion publique latente », qui intègre des dimensions d’intensité et de propension à changer. Ils jugent les sondages utiles mais insuffisants pour appréhender l’opinion publique; aussi l’interprètent-ils à partir de conversations et d’un certain « sens de l’opinion publique ». Selon eux, les médias peuvent influencer l’opinion publique, mais surtout influencer la tenue d’une délibération publique et la façon dont les décideurs lisent l’opinion publique. Ils estiment aussi pouvoir, par leur travail journalistique, favoriser l’émergence d’une opinion publique raisonnée, ce qui est conforme à leur idéal de démocratie participative. / The notion of public opinion is central to political action and media coverage of politics, in western democracies. It usually refers to the sum of all citizens’ individual attitudes, and to survey results. Yet, the limitations of public opinion thus conceptualized appears ever more clearly to scholars, calling into question its value as an input to the political process. In order to better understand the role of public opinion in the political process in Quebec, we have been seeking to understand how some important political actors — elite francophone political columnists and editorialists — view public opinion. By interviewing those journalists, we gathered their “lay theories”, i.e. the way they understand public opinion and its place in the democratic process. We found out that these pundits distinguish different types of public opinion, which are of unequal value to them. They are mostly interested in “latent public opinion”, a concept that includes dimensions of intensity and transformation potential of opinion. They believe surveys are somewhat useful, but incomplete tools for assessing public opinion. Therefore, they turn to other means of knowing it: conversations, and a certain “public opinion sense”. According to them, the media can have an influence on public opinion, but above all it can have an influence on public deliberation and on the way politicians view public opinion. Respondents also believe they can contribute, by their journalistic work, to the construction of a more considered public opinion — which is in tune with their ideal of participatory democracy.

L’utilisation des mesures subjectives en épidémiologie s’est intensifiée récemment, notamment avec la volonté de plus en plus affirmée d’intégrer la perception qu’ont les sujets de leur santé dans l’étude des maladies et l’évaluation des interventions. La psychométrie regroupe les méthodes statistiques utilisées pour la construction des questionnaires et l’analyse des données qui en sont issues. Ce travail de thèse avait pour but d’explorer différents problèmes méthodologiques soulevés par l’utilisation des techniques psychométriques en épidémiologie. Trois études empiriques sont présentées et concernent 1/ la phase de validation de l’instrument : l’objectif était de développer, à l’aide de données simulées, un outil de calcul de la taille d’échantillon pour la validation d’échelle en psychiatrie ; 2/ les propriétés mathématiques de la mesure obtenue : l’objectif était de comparer les performances de la différence minimale cliniquement pertinente d’un questionnaire calculée sur des données de cohorte, soit dans le cadre de la théorie classique des tests (CTT), soit dans celui de la théorie de réponse à l’item (IRT) ; 3/ son utilisation dans un schéma longitudinal : l’objectif était de comparer, à l’aide de données simulées, les performances d’une méthode statistique d’analyse de l’évolution longitudinale d’un phénomène subjectif mesuré à l’aide de la CTT ou de l’IRT, en particulier lorsque certains items disponibles pour la mesure différaient à chaque temps. Enfin, l’utilisation de graphes orientés acycliques a permis de discuter, à l’aide des résultats de ces trois études, la notion de biais d’information lors de l’utilisation des mesures subjectives en épidémiologie. / Recently, subjective measurements have increasingly been used in epidemiology, alongside the growing will to integrate individuals’ point of view on their health in studies on diseases or health interventions. Psychometrics includes statistical methods used to develop questionnaires and to analyze questionnaire data. This doctoral dissertation aimed to explore methodological issues raised by the use of psychometric techniques in epidemiology. Three empirical studies are presented and cover 1 / the validation stage of a questionnaire: the objective was to develop, using simulated data, a tool to determine sample size for internal validity studies on psychiatric scale; 2 / the mathematical properties of the subjective measurement: the objective was to compare the performances of the minimal clinically important difference of a questionnaire, assessed on data from a cohort study, computed using the classical test theory (CTT) framework or the item response theory framework (IRT); 3 / its use in a longitudinal design: the objective was to compare, using simulated data, the performances of a statistical method aimed to analyze the longitudinal course of a subjective phenomenon measured using the CTT or IRT framework, especially when some of the available items used for its measurement differ at each time of data collection. Finally, directed acyclic graphs were used to discuss the results from these three studies and the concept of information bias when subjective measurements are used in epidemiology.