171 |
Proposta e avaliação de uma arquitetura ROADM para sistemas de transmissão O-OFDM / Proposal and evaluation of a ROADM architecture for O-OFDM transmission systemsFerreira, Rafael Jales Lima 26 June 2018 (has links)
Este trabalho tem como cenário as redes ópticas de próxima geração, por onde trafegarão supercanais flexíveis, sincronizados e modulados a taxas variáveis que podem chegar à ordem de Terabit por segundo. Mais especificamente, focaliza o supercanal óptico gerado a partir de um único laser (laser semente) composto por portadoras ortogonais entre si, travadas em frequência e moduladas de maneira síncrona. Tal arranjo constitui um sistema de transmissão conhecido como OFDM óptico (optical orthogonal frequency division multiplexing, O-OFDM). Este esquema não requer banda de guarda entre canais, o que proporciona uma melhor eficiência espectral, se mantidas as condições de ortogonalidade mútua, quando comparado à técnica Nyquist WDM (Nyquist wavelength division multiplexing, N-WDM), usualmente reconhecida como base para os sistemas de próxima geração. Muitos são os desafios a serem vencidos antes que a técnica O-OFDM possa ser efetivamente implantada comercialmente e esta tese busca, através de um estudo de seus princípios de funcionamento e módulos constituintes, elencar os principais obstáculos e as possíveis maneira de superá-los. Sem pretender ser exaustivo em termos de tecnologias disponíveis para alcançar este fim, o objetivo é propor novas configurações de subsistemas e arquitetura de nó para o transmissor, o nó intermediário e o receptor coerente, capazes de executar, de forma relativamente simples no domínio óptico, as principais funcionalidades de uma transmissão ponto a ponto com nós deriva/insere intermediários. Através de simulações sistêmicas e demonstrações experimentais, como prova de conceito, dois cenários são abordados: análise do desempenho numa transmissão ponto a ponto, e operação em rede, com derivação e inserção de canal em nós intermediários. Ao final, através de uma análise qualitativa, é feita uma estimativa de componentes e subsistemas necessários para tornar a transmissão de sinais O-OFDM implementável por tecnologias de fotônica integrada que atenda, com eficiência espectral e economia de energia, a sempre crescente demanda de capacidade em sistemas de transmissão óptica. / This work focuses on the scenario of next generation optical networking, where flexible optical superchannels will propagate modulated at variable rates that can reach terabits per second. More specifically, it focuses on the optical superchannel generated from a single laser (seed laser) composed of orthogonal carriers, which are frequency-locked and synchronously modulated. Such arrangement constitutes a transmission system known as optical orthogonal frequency division multiplexing (O-OFDM). This scheme does not require guard band between channels, which provides a better spectral efficiency, if the conditions of mutual orthogonality are maintained, when compared to the Nyquist wavelength dividing multiplexing (N-WDM) technique, usually recognized as the basis for the next generation systems. There are many challenges to overcome before O-OFDM technique can be effectively deployed commercially and this thesis seeks, through a study of its operating principles and constituent modules, to identify the main obstacles and the possible ways of overcoming them. Without intending to be exhaustive in terms of available technologies to achieve this aim, the objective is to propose new configurations of subsystems and node architecture for the transmitter, the intermediate node and the coherent receiver, able to perform in the optical domain, in a relatively simple way, the main features a point-to-point transmission with nodes drifting/inserting intermediates. Through systemic simulations and some experimental demonstrations, as proof of concept, two scenarios are addressed: performance analysis in a point-to-point transmission, and network operation, with channel derivation and insertion at intermediate nodes. At the end, through a qualitative analysis, an estimate of components and subsystems is made to make the transmission of O-OFDM signals implementable by integrated photonics technologies that meet, with spectral efficiency and energy savings, the ever increasing capacity demand in optical transmission systems.
|
172 |
Techniques et métriques non intrusives pour caractériser les réseaux Wi-Fi / Metrics and non-intrusive techniques to characterize Wi-Fi networksMolina Troconis, Laudin Alessandro 05 July 2018 (has links)
Aujourd’hui, les appareils mobiles sont présents dans le monde entier. Ces appareils permettent aux utilisateurs d'accéder à l’Internet notamment par l'intermédiaire des réseaux WiFi. La diversité et le nombre de déploiements sans coordination centrale (y compris les utilisateurs à leur domicile) conduit à des déploiements qu’on peut qualifier de chaotiques. En conséquence, les réseaux WiFi sont largement déployés avec une forte densité dans les zones urbaines. Dans ce contexte, les utilisateurs et les opérateurs tentent d’exploiter ces déploiements pour obtenir une connectivité omniprésente, et éventuellement d'autres services. Cependant, pour tirer parti de ces déploiements, il faut des stratégies pour identifier les réseaux utilisables et choisir les plus adaptés aux besoins. Pour cela, nous étudions le processus de découverte des réseaux dans le contexte de ces déploiements. Ensuite, nous présentons une plateforme de partage de mesures sans fil, un système d'information collaboratif où les stations mobiles recueillent des mesures du réseau et les envoient à un système central. En rassemblant mesures provenant de différents utilisateurs, la plateforme donne accès à des caractéristiques du déploiement précieuses. Nous évaluons l'utilité de cette plateforme collaborative grâce à deux applications : (1) l’ensemble minimal de points d'accès, afin de réduire l'énergie nécessaire pour offrir une couverture WiFi dans une zone donnée. (2) l'optimisation des paramètres de recherche de réseau, afin de réduire le temps nécessaire pour découvrir les réseaux existants. Ensuite, nous étudions une méthode passive pour déterminer si un réseau fonctionne dans un canal saturé. / Nowadays, mobile devices are present worldwide, with over 4.40 Billion devices globally. These devices enable users to access the Internet via wireless networks. Different actors (e.g., home users, enterprises) are installing WiFi networks everywhere, without central coordination, creating chaotic deployments. As a result, WiFi networks are widely deployed all over the world, with high accesspoint (AP) density in urban areas. In this context, end-users and operators are trying to exploit these dense network deployments to obtain ubiquitous Internet connectivity, and possibly other services. However, taking advantage of these deployments requires strategies to gather and provide information about the available networks. In this dissertation, we first study the network discovery process within the context of these deployments. Then, we present the Wireless Measurements Sharing Platform, a collaborative information system, to which mobile stations send simple network measurements that they collected. By gathering and processing several network measurements from different users, the platform provides access to valuable characteristics of the deployment. We evaluate the usefulness of this collaborative platform thanks to two applications: (1) the minimal access point set, to reduce the energy needed to offer WiFi coverage in a given area.(2) The optimization of the scanning parameters,to reduce the time a mobile station needs for the network discovery. Finally, we describe a method to identify whether an AP operates ina saturated channel, by passively monitoring beacon arrival distribution.
|
173 |
Sistema de ar condicionado com insuflamento pelo piso em ambientes de escritórios: avaliação do conforto térmico e condições de operação. / Underfloor air supply system applied to office buildings: thermal comfort and operational conditions evaluation.Leite, Brenda Chaves Coelho 06 March 2003 (has links)
Desde a introdução do conceito de escritório aberto, o tipo de ocupação e a distribuição das cargas internas têm sofrido grandes mudanças, requerendo maior flexibilidade nos edifícios. Além disto, avaliações de desempenho de edifícios de escritórios da atualidade têm apresentado resultados que são fortes indicadores da necessidade de mudanças de conceitos de projeto, operação e uso de sistemas de condicionamento de ar, devido ao elevado nível de insatisfação dos usuários quanto ao conforto e à qualidade do ar. Para tentar solucionar estes problemas, outro conceito em distribuição de ar, já em uso nos países desenvolvidos, está começando a ser adotado também no Brasil; trata-se de insuflamento pelo piso, com difusores instalados em placas de piso elevado e nas estações de trabalho, que permitem flexibilidade e controle individual de vazão de ar. Neste trabalho foi feita a avaliação de sistema de condicionamento de ar com insuflamento pelo piso em um laboratório com condições controladas. O laboratório em que foram realizados os ensaios foi projetado e instalado com características similares àquelas de ambientes reais de edifícios de escritórios. Este fato, aliado à participação de usuários no processo de avaliação das condições de conforto térmico, tornaram possível a definição de parâmetros para a elaboração de projetos bem como para o estabelecimento de um modo eficaz de operação do sistema. O processo de avaliação das condições de conforto térmico no ambiente envolveu três etapas. Inicialmente, foram feitas medições das variáveis de conforto térmico no ambiente e de variáveis do sistema utilizando simuladores. Posteriormente, foi realizada a avaliação subjetiva do conforto térmico, com a substituição dos simuladores por pessoas no ambiente (usuários), nas mesmas condições da etapa anterior. Finalmente, foram feitas as medições das variáveis de conforto nas zonas de ocupação micro climas na condição de condicionamento individualizado, promovido por ajustes de vazão de ar e direcionamento do fluxo pelos usuários. Os resultados da avaliação permitem concluir que o sistema de condicionamento de ar com insuflamento pelo piso atende às expectativas para promover conforto térmico aos usuários de edifícios de escritórios com potencial de conservação de energia. / Since the introduction of the landscape office concept, the layout type and the internal loads distribution have changed significantly, requesting larger flexibility in the buildings. Besides, building performance evaluation applied to contemporary office buildings has shown that for most such buildings thermal comfort and air quality users level satisfaction is low. These facts are indicating that project concepts, operation and use of air conditioning systems need to be changed. In order to solve these problems, underfloor air supply is becoming a common practice also in Brazil. This system with floor and workstation diffusers allows flexibility and an individualized airflow control. In this work the evaluation of the underfloor air conditioning system was carried out in a laboratory facility with controlled conditions. The laboratory was designed and built up with similar characteristics to those of actual office buildings environments. This fact and the participation of users in the process of thermal comfort evaluation, made possible the definition of design parameters as well as the establishment of the system operation conditions in an effective way. The evaluation of the environment thermal comfort conditions was accomplished in three stages. Initially, measurements of thermal comfort and system variables were made using simulators. Later, in the same conditions of the previous stage, users (a sample of people) have evaluated, in a subjective way, the environment thermal comfort. Finally, measurements of the comfort variables were accomplished in the occupation areas - microclimates - in the condition of individualized conditioning, promoted by air flow adjustments and flow direction by the users. The results of the evaluation allow to conclude that the underfloor air conditioning system satisfies to the expectations to promote thermal comfort to the office building users with potential of energy conservation.
|
174 |
O desempenho térmico de um sistema de cobertura verde em comparação ao sistema tradicional de cobertura com telha cerâmica. / The thermal performance of green roof system in comparison to the traditional ceramic tile roof system.Ferraz, Iara Lima 29 March 2012 (has links)
As coberturas verdes fazem parte da arquitetura vernacular há séculos como solução para regulação térmica das edificações, retardando a transferência de calor para o ambiente interno e, no inverno, retardando as perdas de calor dos ambientes internos para o exterior da edificação (International Green Roof Association - IGRA). Em se adotando cobertura verde em edificações supõe-se haver economia no consumo de energia para se obter condições de conforto térmico nos ambientes. Baseado nessa suposição foi realizada uma pesquisa experimental onde, por meio de um estudo comparativo entre dois tipos de cobertura: a verde e a de telhas cerâmicas comprovou-se o potencial de economia de energia. A análise do comportamento térmico das coberturas verdes foi realizada por meio de coleta de dados de variáveis ambientais, durante um período de 10 meses, de um protótipo instrumentado, construído no Departamento de Engenharia de Construção Civil da Escola Politécnica da USP, São Paulo. Os dados levantados foram comparados com os dados de um segundo protótipo de mesmas dimensões e igualmente instrumentado, com cobertura cerâmica, sob as mesmas condições ambientais. A comparação dos resultados e análises em dias e episódios representativos de cada estação comprovaram a eficiência das coberturas verdes para retardar o ganho térmico da edificação. Espera-se que os resultados sejam incentivadores à larga aplicação dos telhados egetados, o que trará diversas vantagens para população. / Green roofing is been a part of the vernacular architecture for centuries as solution for constructions thermal regulation. It is known that they delay the heat transfer from the outside to the inside of the building, and during winter, they delay the heating loss from the inside to the outside of the building (International Green Roof Association - IGRA). By adopting green roofs in buildings, one assumes that there is economy in energy consumption to obtain conditions of thermal comfort in inner environments. Based on this assumption, an experimental research was accomplished where, through a comparative study between two types of roofing systems: green and ceramics, it was determined this energy saving potential of green roofs. The analysis of the green roofing thermal behavior was realized through data collection of environmental variables, during the period of ten months, from an instrumented prototype constructed at the Polytechnic School of the University of São Paulo, São Paulo. The collected data was compared to those of a second prototype with the same dimensions and equally instrumented, with ceramics roofing, under the same environmental conditions. The data comparison and analysis of specific days in each season, proved the green roof efficiency on retarding the building thermal gain. One expects that the results will encourage the application of green roofs, which will bring several advantages to the population.
|
175 |
Modélisation dynamique des échangeurs diphasiques, appliquée aux groupes frigorifiques contrôlés par une commande avancée / Dynamic modeling of two-phase exchangers applied to refrigeration units controlled by an advanced controlFallahsohi, Hossein 26 April 2011 (has links)
Le contrôle précis des boucles de régulation existantes sur une machine frigorifique est essentiel à son bon fonctionnement. Il existe plusieurs méthodes de régulation parmi lesquelles on retrouve la plus ancienne et la plus connue : la commande PID (Proportionnelle, Intégrale et Dérivée). Malgré la simplicité apparente des relations mises en jeu, le régulateur PID est assez délicat à ajuster sur des processus présentant de fortes perturbations comme les installations frigorifiques. L’objectif du travail présenté est de mettre en œuvre une commande prédictive fonctionnelle (PFC) afin de réguler la surchauffe en sortie d’évaporateur, la pression de condensation et la puissance frigorifique sur une installation munie d’un compresseur à vitesse variable. L’utilisation d’une commande PFC nécessite de réaliser une prédiction de l’évolution à venir de la sortie du procédé. C’est un modèle interne qui fait office de modèle de connaissance. En assimilant le procédé à un système du premier ordre, la mise en œuvre de cette commande ne nécessite que trois paramètres : un gain statique, une constante de temps et un retard pur. L’originalité de la démarche développée a consisté à réaliser une modélisation physique de la machine afin de déterminer les paramètres précédents par une approche macroscopique. Une bibliothèque de modèles physiques a été élaborée permettant de simuler le comportement de différents évaporateurs, condenseurs, compresseurs ou vannes de détente. La commande développée a ensuite été implantée sur un automate industriel programmable et des expériences ont été réalisées sur deux machines différentes. La première est constituée de deux échangeurs à tubes et calandre et d’un compresseur à pistons, alors que la seconde comprend un évaporateur à plaques, une batterie à ailettes et un compresseur à vis. / An accurate control of fluids flow is essential in any refrigeration system. As the conventional Proportional-Integral-Derivative (PID) control with invariable parameters can lead to unsatisfactory performance because of the variation of refrigeration unit parameters under disturbances, the aim of the work presented here is to develop a method for using Predictive Functional Control (PFC) to regulate the evaporator superheat, the condensing pressure and the cooling capacity on a variable-speed refrigeration system. Using a predictive controller requires to predic future change at the output of the process. This prediction is based on an internal model used as known model. By assuming that the behaviour of refrigerating machine heat exchangers can be represented using a first-order model, the implementation of PFC requires only three parameters: gain, time constant and time delay. In order to determine these parameters an original method has been developed which is based on the physical modelling of the machine. Physical models for different types of evaporator, condenser, compressor or expansion valve have been established to quantify heat transfer and refrigerant flow rate in these components. The control system created has been incorporated into an industrial programmable logic controller and used for experiments on two different refrigerating machines: the first one is composed of two shell and tube heat exchangers and a reciprocating compressor, whereas the second one is composed of a plate evaporator, a finned-tube condenser and a screw compressor. The tests performed show that PFC controller succeed in maintaining a precise chilled liquid temperature.
|
176 |
Système actif d'aide à une conduite Eco avec prise en compte de l'interaction conducteur-véhicule-usage / Active Eco driving support system with consideration of driver-vehicle-road interactionJavanmardi, Setareh 28 November 2017 (has links)
L’éco-conduite a été identifié comme l’un des moyens efficaces pour l’économie d’énergie dans le domaine des véhicules terrestres. Le gain potentiel en consommation ainsi que sa facilité de mise en œuvre, rendent cette solution très recherchée dans le milieu industriel pour à la fois améliorer la consommation des véhicules mais aussi satisfaire les utilisateurs. Cette thèse contribue au développement d’un système actif d’aide à l’éco-conduite pour assister le conducteur dans son économie d’énergie. Ce système s’appuie sur une optimisation énergétique et tient compte de l’interaction du conducteur avec le véhicule et son usage (la route). Nous avons tout d’abord développé un modèle multi-variable de style de conduite pour représenter le conducteur humain par un modèle virtuel. L’identification des paramètres de ce modèle a permis de caractériser trois styles de conduite sur plusieurs cas d’usage et de reproduire de manière assez fidèle les trois niveaux de consommation de carburant. Considérant les cas d’usage péri-urbains et autoroutiers, le problème d’optimisation de la trajectoire sur des critères énergétiques a été reformulé afin de déterminer un profil de vitesse constant par morceaux minimisant la consommation d’énergie, tout en respectant la durée de trajet désirée et les limitations de vitesse. Le profil de vitesse optimal fournit des vitesses cibles, informations du premier ordre pour réduire la consommation. Plusieurs extensions ont été ensuite introduites dans la trajectoire optimale afin d’y intégrer l’anticipation des phases de décélération et les phases d’accélération. L’originalité principale de cette approche est le temps de calcul extrêmement faible, tout en obtenant des résultats très proches des résultats optimaux issus de méthodes classiques d’optimisation (ex. programmation dynamique). Afin d’aller encore plus loin dans l’éco-conduite, nous avons étudié la possibilité de réduire la consommation d’énergie en intégrant des stratégies de conduite telle que le ''swaying'' qui consiste en une oscillation de la vitesse du véhicule autour d’une vitesse moyenne. Nous avons alors pu montrer que, « en théorie », il existe bien des paramètres permettant de réduire la consommation de cette manière. Le système actif d’aide à l’éco-conduite a donc été développé en conjuguant les deux aspects précédents. Il se base sur le partage de la commande moteur entre le conducteur humain et un contrôleur optimal. Des niveaux de partage variables ont été établis afin de représenter différents niveaux d’économie d’énergie et d’intervention sur la conduite du conducteur. Enfin, ce système d’aide actif a été testé expérimentalement sur un simulateur de conduite. / Eco-driving has been identified as one of the most effective ways to save energy in the field of ground vehicles. The potential gain in fuel consumption reduction as well as its easy implementation, make this solution very sought after in the industrial environment for improving both the fuel consumption of vehicles and the user satisfaction. This thesis contributes to the development of an active eco-driving support system for assisting the driver to improve his fuel economy. This system is based on energy optimization and takes into account the driver's interaction with the vehicle and its use (the road). For this purpose, first of all a multi-variable driving style model is developed to represent the human driver by a virtual model. The identification of the parameters of this model made it possible to characterize three driving styles in several use cases and to reproduce the three levels of fuel consumption fairly accurately. Considering the suburban and motorway use cases, the trajectory optimization problem based on energy criteria has been reformulated in order to determine a piecewise constant velocity profile minimizing energy consumption, while respecting constraints on trip duration and velocity limitations. The optimal velocity profile provides target cruising velocity, which is the first order information to reduce fuel consumption. Several extensions were then introduced in the optimal trajectory in order to incorporate the anticipation of the deceleration phases and the acceleration phases. The main originality of this approach is the extremely low computation time, while obtaining results very close to the optimal solution, achieved by classical optimization methods (e.g. dynamic programming). In order to investigate even further in eco-driving, we have studied the possibility of reducing energy consumption by integrating driving strategies such as ''swaying'', which consists of an oscillation of the vehicle's speed around an average speed. We were then able to show that, "theoretically", this problem can be parametrized so that the energy consumption is reduced. The active eco-driving support system was therefore developed by combining the two previous aspects. It is based on the shared control of the engine between the human driver and an optimal controller. Variable sharing laws have been established to represent different levels of optimal controller intervention on human driver driving, which results to different levels of fuel economy. Finally, this active support system has been tested experimentally on a driving simulator.
|
177 |
Roteamento de tráfego e alocação de recursos em redes ópticas WDM com base em economia de energia / Energy-aware traffic routing and resource allocation in WDM optical networksLlerena Valdivia, Nereida Celina 28 November 2014 (has links)
O crescimento do tráfego de serviços de telecomunicações tem aumentado o consumo de energia e, em consequência, aumentado as emissões de CO2 que tem efeitos nocivos sobre o meio ambiente. É assim que a economia de energia torna-se um fator chave no planejamento de redes de telecomunicações. Para garantir a disponibilidade e confiabilidade, as redes possuem arquitetura redundante e são projetadas para suportar a demanda de pico de tráfego. Redes com mecanismos de proteção como proteção dedicada de caminhos (DPP), proveem caminhos alternativos para cada demanda de conexão. Os elementos da rede que suportam esses caminhos estão em estado ativo (consumindo energia), apesar de, na maior parte do tempo, não transportarem tráfego efetivo. Um método para diminuir o gasto de energia é utilizar roteamento adaptado à carga real de tráfego baseado em modo suspenso (estado de baixo consumo de energia que pode passar a estado ativo rapidamente). Assim, o tráfego é roteado com vistas à maximizar a quantidade de componentes que são parte de caminhos de proteção, que podem ser postos em modo suspenso. Neste trabalho, as redes usadas para os testes são a rede europeia Cost239, a rede estadunidense UsNet e a rede brasileira Ipê. Abordamos o problema de economia de energia em redes WDM com DPP através de quatro estratégias de roteamento. Cada uma tem objetivos diferentes, a Shortest Path-DPP (SP-DPP) faz o roteamento por caminho mais curto, a Energy Aware-DPP (EA-DPP) aloca as demandas por enlaces que estejam ativos, a Energy Aware-DPP with Mixing (EA-DPP-MixS) evita que caminhos principais sejam roteados por enlaces que já são parte de caminhos de proteção e a Energy Aware-DPP with Differentation (EA-DPP-Dif) evita a mistura de caminhos por um mesmo enlace. Em nossas simulações computacionais observamos que a EA-DPP-Dif economiza energia de maneira eficiente, mas a probabilidade de bloqueio aumenta. A EA-DPP-MixS diminui o bloqueio em detrimento da energia economizada. Já a SP-DPP e a EA-DPP são menos eficientes na diminuição da energia consumida. É assim que propomos um roteamento com busca de recursos mais ampla, usando cada uma das estratégias. A proposta será chamada de roteamento intensivo. A EA-DPP-Dif-Intensivo diminui a probabilidade de bloqueio e economiza energia mediante modo suspenso. Neste trabalho, analisamos o desempenho das estratégias para cada uma das redes e avaliamos o impacto da energia economizada sobre a probabilidade de bloqueio. A proposta de roteamento i>intensivo diminui a energia consumida em até 50%, diminuindo a probabilidade de bloqueio. Porém, os resultados estão diretamente relacionados com a carga de rede e as características particulares da topologia de cada rede. / The growth of data traffic in telecommunication networks has increased energy consumption and hence increased CO2 emissions, with harmful effects on the environment. Thus, energy saving becomes a key and a differential factor when planning telecommunication networks. In order to guarantee availability and reliability, core networks have redundant architecture and are designed to support peak-hour traffic demand. Networks with dedicated path protection (DPP) mechanisms provide alternative paths for each connection request. Network elements supporting these paths are in active state (consuming energy), although most of the time they dont carry traffic. One technique to decrease energy waste is by adaptive real traffic routing using sleep mode (a low energy consumption state which is able to rapidly change to an active state). Thus, traffic is routed in order to maximize the amount of network components used by protection paths, which can be set in sleep mode. In this work, European Cost239, American UsNet and Brazilian Ipê networks were used in computational simulations. We addressed the energy saving problem in WDM networks with DPP through four routing strategies, each with different goals. The Shorthest Path-Dedicated Path Protection (SP-DPP) technique uses shortest path for routing, Energy Aware-Dedicated Path Protection (EA-DPP) allocates demands in active links, Energy Aware-Dedicated Path Protection with Mixing (EA-DPP-MixS) prevents primary paths to be formed by links that are already part of the protection paths and Energy Aware-Dedicated Path Protection with Differentation (EA-DPP-Dif) prevents mixing primary and protection paths through the same link. We observe that EA-DPP-Dif efficiently saved energy, however blocking probability has increased. EA-DPP-MixS reduced blocking rather than saved energy. At least, SP-DPP and EA-DPP are less efficient in reducing energy consumption. Hence, we propose a wider resource search routing, the in-depth routing, using each of these strategies. Thus, EA-DPP-Dif-In-depth decreased blocking probability while maintaining energy saving through sleep mode. In this work, we analyze the strategies performance for each network and evaluate the impact of energy saved on the blocking probability. Our in-depth routing strategy reduced the energy consumption up to 50%, decreasing blocking probability. However, the results are directly related with the network load and the specific properties of each network topology.
|
178 |
De l’innovation des instruments de politique publique : développement d'une méthode de conception combinatoire autour d'un langage algorithmique et application au dispositif des certificats d’économie d’énergie / Innovation of public policy instruments : development of a combinatory design method via an algorithmic language and application to the energy saving certificates schemeBaïz, Adam 06 December 2018 (has links)
En dépit de ses diverses caractérisations, la nature innovante des instruments de politique publique semble consacrer trois types d’innovation : (a) soit, des imitations, à un glissement de modalités près, d’instruments préexistants ; (b) soit des hybridations d’instruments plus ou moins contraignants ; (c) soit des assemblages d’instruments de nature méta-instrumentale. En admettant alors que tous les instruments découlent les uns des autres par le biais de ces trois chemins de conception, nous avons cherché à produire une méthode de conception fondant concomitamment, et autour d’un même modèle-objet, une capacité d’identification ex post des instruments innovants et une capacité ex ante d’innovation.Au terme d’une démarche de recherche-intervention, nous avons convenu de définir les instruments comme autant de chaînes de causalité préfigurées de l’action collective, et avons formulé un langage algorithmique autour d’un certain nombre d’éléments - des acteurs, des actions, des événements, des opérateurs logiques et des vecteurs d’impact – afin de les caractériser de façon ostensive. En consacrant une méthode d’évaluation de la nouveauté et de l’effectivité instrumentales, nous avons dès lors pu établir qu’un instrument est innovant s’il constitue une nouvelle chaîne de causalité opérant effectivement dans la réalité technico-sociale. De façon corollaire, innover un instrument revient alors à dessiner une nouvelle chaîne de causalité, ou à modifier les acteurs et les actions qui la composent.Afin d’illustrer et d’éprouver cette méthode de conception que nous qualifions de combinatoire, nous avons enfin cherché à interroger le caractère innovant du dispositif des certificats d’économie (CEE) et ce, en proposant un protocole d'évaluation et en formulant diverses pistes d'innovation. / Although it is diversely characterized, the innovative nature of instruments seems to follow three types of innovation: (a) imitations of existing instruments; (b) hybridizations of more or less coercive instruments; (c) or meta-conglomerations of instruments. After admitting that all instruments originate from one another through these three innovation paths and a unique object model, we tried to provide a new design method that would both enable the identification of innovative instruments and their design.Within the frame of intervention research, we agreed to define an instrument as a specific intended causal chain of public action, and formulated an algorithmic language along some instrumental elements (actors, actions, events, logical operators and impact vectors) in order to characterize instruments in an ostensive way. After developing a method to evaluate the newness and the effectivity of any instrument, we could more precisely define an innovative instrument as a new causal chain that is effectively implemented in the technical and social reality. As a corollary, innovating an instrument consists in designing a new causal chain, or modifying the actors and actions in it.Eventually, and in order to apply and test what we called a combinatory design method, we chose to question the innovative nature of the Energy Savings Certificates scheme (ESC). For this purpose, we elaborated an evaluation protocol and formulated several possible lines of innovation.
|
179 |
Hierarquia de memória configurável para redução energética no codificador de vídeo HEVC / Configurable memory hierarchy for energy reduction in HEVC video encoderMartins, Anderson da Silva 29 September 2017 (has links)
Submitted by Aline Batista (alinehb.ufpel@gmail.com) on 2018-04-18T14:40:46Z
No. of bitstreams: 2
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Dissertacao_Anderson_Martins.pdf: 8654389 bytes, checksum: f6e25bd57867fb8466bfe88dcf25afb3 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-04-19T14:42:52Z (GMT) No. of bitstreams: 2
Dissertacao_Anderson_Martins.pdf: 8654389 bytes, checksum: f6e25bd57867fb8466bfe88dcf25afb3 (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-04-19T14:43:00Z (GMT). No. of bitstreams: 2
Dissertacao_Anderson_Martins.pdf: 8654389 bytes, checksum: f6e25bd57867fb8466bfe88dcf25afb3 (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Previous issue date: 2017-09-29 / Sem bolsa / Dados recentes mostram que há uma demanda crescente de aplicações de vídeo em dispositivos móveis, sendo este um grande desafio para pesquisas em arquiteturas de codificadores de vídeo de alto desempenho como o padrão HEVC. Em um sistema embarcado o consumo de energia e o desempenho estão diretamente ligados ao sistema de memória. No codificador de vídeo não é diferente, e no HEVC a etapa de estimação de movimento (ME) é conhecida por ser responsável pela maior parte do tempo de processamento e acesso à memória. Portanto, este trabalho apresenta uma exploração do espaço de projeto para definir configurações de memória cache eficientes em energia para o processo da ME e, propor uma hierarquia de memória cache configurável, considerando diferentes sequências de vídeo e configurações do codificador HEVC. A avaliação considerou o algoritmo TZ Search, amplamente utilizado, 23 sequências de vídeo com resoluções distintas e quatro Parâmetros de Quantização (QPs) sob 32 configurações de cache diferentes. Um simulador de cache foi desenvolvido e a ferramenta CACTI foi utilizada para obter parâmetros de tempo e energia. Assim, foi possível identificar configurações de cache ótimas para cada cenário, visto que não existe uma única configuração de memória cache que satisfaça todos os cenários ao mesmo tempo quando o objetivo é redução de energia. Considerando a configuração ótima de cache para cada cenário, o uso de cache pode levar a uma economia de largura de banda da memória externa de até 97,37%, que corresponde a uma redução de 25,48GB/s para 548,53MB/s em um caso. A redução de energia chega a 93,95%, o que corresponde, uma redução de energia de 5,02mJ para 0,30mJ, ao comparar diferentes configurações de cache. Estes resultados possibilitaram propor uma hierarquia de memória cache configurável para o processo de estimação de movimento que é capaz de atender eficientemente todos os cenários testados. Para a arquitetura configurável proposta foram encontradas economia de energia de até 78,09% quando as configurações ótimas são comparadas com o pior caso dentro da cache configurável (16KB-8). Já quando comparada com Level-C, foram alcançadas economia de energia de até 86,91%. Além disso, a economia de largura de banda alcançada ficou entre 90,21% e 96,84% com uma média de 94,97%. / Recent data show that there is a growing demand for video applications on mobile devices, which is a major challenge for research into high performance video encoder architectures such as the HEVC standard. In an embedded system, power consumption and performance are directly connected to the memory system. In the video encoder it is no different, and in the HEVC the motion estimation (ME) step is known to be responsible for most of the processing time and memory access. Therefore, this work presents an exploration of the design space to define energy-efficient cache memory configurations for the ME process and propose a configurable cache memory hierarchy considering different video sequences and HEVC encoder configurations. The evaluation considered the widely used TZ Search algorithm, 23 video sequences with distinct resolutions, and four Quantization Parameters (QPs) under 32 different cache configurations. A cache simulator was developed and the CACTI tool was used to obtain time and energy parameters. Thus, it was possible to identify optimal cache configurations for each scenario, since there is no single cache configuration that satisfies all scenarios at the same time when the goal is to reduce power. Considering the optimal cache configuration for each scenario, cache usage can lead to external memory bandwidth savings of up to 97.37%, which corresponds to a reduction of 25.48GB/s to 548.53MB/s in one case. The energy reduction comes to 93.95%, which corresponds to an energy reduction of 5.02mJ to 0.30mJ when comparing different cache configurations. These results have made it possible to propose a configurable cache memory hierarchy for motion estimation process that is capable of efficiently satisfying all scenarios tested. For the proposed configurable architecture, energy savings of up to 78.09% were found when the optimal configurations were compared to the worst case within the configurable cache (16KB-8). When compared to Level-C, energy savings of up to 86.91% were achieved. In addition, the external memory bandwidth savings achieved was between 90.21% and 96.84% with an average of 94.97%.
|
180 |
Contributing to energy efficiency through a user-centered smart home / Contribution à la gestion efficace de l'énergie dans le contexte d'une maison intelligente ''centrée utilisateur''Dominici, Michele 03 June 2013 (has links)
Les maisons intelligentes sont des habitations équipées de technologies de l'information et de la communication qui anticipent et répondent aux besoins des occupants. Malgré les nombreux travaux et solutions existants, seulement peu d'exemplaires de maisons intelligentes ont été construits et vendus. La raison cachée derrière cette lente diffusion est l'orientation technologique des approches existantes. Cette thèse de doctorat vise à démontrer qu'une maison intelligente peut fournir des fonctionnalités conçues avec une approche centrée utilisateur, en prenant en compte de considérations ergonomiques sur l'activité domestique et sur la cognition humaine. Ceci est réalisé en collaboration avec des ergonomes cognitifs, qui aident à "prendre garde" à l'écart entre le contexte humain et le contexte compréhensible par une machine. En utilisant une instrumentation légère, qui minimise les problèmes d'acceptabilité et de protection de la vie privée, ce travail de thèse a mené aux contributions suivantes: (i) la conception interdisciplinaire de fonctionnalités adaptées, en collaboration avec des ergonomes cognitifs; (ii) la conception d'un système sensible au contexte qui capture et raisonne sur des informations contextuelles incertaines de façon distribuée; (iii) la réalisation d'un prototype qui démontre la fourniture de fonctionnalités qui réalisent des économies d'énergie, tout en préservant le confort des habitants. / Smart homes are residences equipped with information and communication technologies that anticipate and respond to the needs of the occupants. Despite the numerous research and industrial efforts, today only few expensive smart homes have been built and sold. The reason behind this slow uptake is the technology-driven approach characterizing existing solutions. The doctoral Thesis aims at demonstrating that a smart home can provide functionalities designed with a user-centered approach, taking into account ergonomic considerations about domestic activity and human cognition. This is achieved in collaboration with cognitive ergonomists, which help "minding the gap" between human context and machine-understandable context. Using off-the-shelf and lightweight instrumentation (also minimizing privacy concerns), extending existing context modeling, reasoning and management tools and following the Ubiquitous Computing principles, the doctoral work led to the following achievements: (i) the inter-disciplinary design of suitable functionalities, in collaboration with cognitive ergonomists; (ii) the design of a context-aware system that captures and reasons about uncertain contextual information in a distributed fashion; (ii) the realization of a working prototype that demonstrates the provision of energy-saving and comfort-preserving functionalities.
|
Page generated in 0.0735 seconds