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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Estimativa do estado de carga de baterias em robôs móveis autônomos / Battery state of charge estimation in autonomous mobile robots

Oliveira, Marcelo Manoel de 19 April 2013 (has links)
Cada vez mais robôs móveis autônomos estão sendo utilizados em diversas tarefas e em ambientes com elevado risco para atividades humanas que a paralisação de suas atividades podem gerar outros riscos, perdas e elevados custos. Assim, o estado de carga (SOC) de sistemas de baterias em robôs móveis autônomos é um parâmetro importante na prevenção de uma falha primária nessa aplicação, a ausência de energia. Este trabalho apresenta os métodos existentes na literatura para a determinação do estado de carga de baterias e as tecnologias de baterias disponíveis utilizadas em robôs móveis autônomos ou veículos autônomos guiados. A partir desses estudos foi desenvolvido um modelo de medida, baseado no modelo combinado e foram realizados testes de bancadas para levantamento dos parâmetros e características de três modelos de células de baterias: Lítio Polímero (Li-PO), Níquel-Cádmio (NiCd) e Lítio-Ferro-Polímero (LiFePO4). Com esses parâmetros, aplicou-se o método de estimativa de carga baseado na técnica do Filtro de Kalman Estendido (EKF). Através dos testes, analisou-se comparativamente a resposta do método proposto e a resposta do método OCV e a capacidade de carga real. / Autonomous mobile robots have being increasingly used in various tasks, environments and activities of high risk to human that the stoppage of its activities may generate other risks, losses and high costs. Thus the state of charge (SOC) of battery systems in autonomous mobile robots, is an important parameter to prevent a primary failure in this application, the lack of energy. The paper presents the existing methods in the literature to determine the battery state of charge and battery commercial technologies available used in an autonomous mobile robot or autonomous guided vehicle, from these studies a measurement model based on combined model was developed and testing benches for three cells models on Lithium Polymer Battery (Li-PO), Nickel Cadmium (NiCd) and lithium-iron-Polymer (LiFePO4) batteries were performed for lifting the parameters and apply the battery state of charge method based on the Extended Kalman Filter (EKF) technique. The tests were analyzed in order to observe the comparatively response of the proposed method, the OCV method and Real charge capacity.
282

Modélisation électrique et énergétique des accumulateurs Li-Ion. Estimation en ligne de la SOC et de la SOH / Energetical and electrical modelling of lithium-ion batteries.Online estimation of SOC and SOH

Urbain, Matthieu 04 June 2009 (has links)
Ce mémoire traite de la modélisation électrique des accumulateurs lithium-ion, de l’estimation de leur état de charge (SOC) et de leur état de santé (SOH). Le premier chapitre revient sur les généralités concernant la technologie lithium-ion : caractéristiques, performances, constitution de l’élément de stockage, choix et nature des électrodes, conséquences qui en découlent d’un point de vue énergétique. Le principe de fonctionnement et les équations générales des phénomènes électrochimiques sont aussi développés. Des exemples d’application dans différents secteurs industriels sont ensuite proposés pour plusieurs gammes de puissance et d’énergie. Le second volet aborde la modélisation électrique des accumulateurs lithium-ion. Pour une meilleure compréhension des phénomènes complexes mis en jeu au sein des batteries, des éléments de modélisation physique sont exposés. Puis nous envisageons une synthèse des différents modèles de nature électrique rencontrés dans la littérature. Sur la base de campagnes de mesures menées sur un élément lithium-ion de 6,8 Ah, nous proposons, dans un troisième chapitre, notre propre modèle électrique équivalent valable pour les phases de décharge et de relaxation. En particulier nous déclinons plusieurs solutions pour distribuer l’énergie et rendre compte des différents effets de ligne. Les outils de caractérisation et les procédures d’extractions des paramètres sont traités en détail. Dans un dernier chapitre nous étudions les possibilités d’estimer en ligne l’état de charge (SOC) et l’état de santé (SOH) d’un élément lithium-ion en cours d’exploitation. Après un bref rappel des méthodes académiques et industrielles actuelles, nous nous orientons vers l’emploi d’un filtre de Kalman. Afin d’estimer ses performances par rapport au coulombmètre, nous proposons un modèle et un algorithme que nous évaluons par simulation et testons sur élément réel / This dissertation of thesis deals with the electrical modelling of lithium-ion accumulators and the determination of both state-of-charge (SOC) and state-of-health (SOH). The first chapter is focused on generalities about lithium-ion technology: characteristics, qualities, constitution of the storage device, choice and nature of the electrodes and their consequences on energetical features. The principle and the general equations of the electrochemical phenomena are developed as well. Application examples from different industrial areas are displayed for several power and energy ranges. The second section is about the electrical modelling of lithium-ion accumulators. With a view to better understand the complex electrochemical phenomena, elements of physical modelling are proposed. Then, the synthesis of different electrical models released in the press is considered. On the basis of experimental campaigns lead on a 6.8 Ah lithium-element, we proposed, in a third chapter, our own equivalent electrical model suitable for both discharge phases and relaxation period. In particular, we depict several alternatives to distribute the energy and describe the different line effects. Both characterization tools and parameters extraction procedure are clearly detailed. In the last section, we tackle both SOC and SOH on-line determination. After a short review of academicals and industrial solutions, we rapidly head towards the use of a Kalman filter. In order to compare its features versus the coulombmeter, we propose a model and an algorithm, numerical simulations and experimental tests are performed
283

Découverte d'annuaires de services web dans un environnement distribué / Web services registries discovery in a distributed environment

Sellami, Mohamed 18 October 2011 (has links)
Les services Web (SW) sont considérés comme étant un bloc pilier pour la réalisation de transactions électroniques entre entreprises. Ainsi, de plus en plus d'entreprises utilisent des SW pour réaliser des transactions avec leurs partenaires et/ou offrir des services en ligne. Dans un tel contexte, chaque entreprise possède un ou plusieurs référentiels privés de descriptions de SW. Pour que ses SW soient consultables et puissent être découverts par d'autres entreprises, une entreprise devra rendre ses référentiels de SW publics. La solution couramment utilisée consiste à publier les descriptions de ses SW dans des annuaires de SW. En conséquence, le nombre d'annuaires disponibles peut être aussi important que le grand nombre d'entreprises et la découverte d'un SW devient ainsi une tâche fastidieuse pour un demandeur de services et coûteuse pour un système de découverte. L'objectif principal de cette thèse est de fournir des solutions pour assurer une découverte d'annuaires de SW adaptée à un environnement distribué. Pour ce faire, nous proposons tout d'abord d'organiser le réseau d'annuaires en communautés. Ensuite, afin de préserver la consistance de cette organisation face aux changements qui peuvent se produire (départ/arrivée d'annuaires), nous définissons les mécanismes de gestion nécessaires. Enfin, nous proposons une approche pour la découverte d'annuaires de SW qui utilise deux filtres pour limiter l'espace de recherche d'un demandeur de services. Les solutions proposées ont été testées par la mise en place d'un réseau de communautés d'annuaires, l'implémentation d'un gestionnaire de communautés et d'un système de découverte d'annuaires. / Web services (WS) can be seen as a pillar block for achieving electronic B2B transactions. More and more companies are using WS to achieve transactions with their partners and/or offer on-line services. These companies have to make their WS available for consultation through their own private WS registries. As a result, the number of WS registries that are made available for use can be as many as the large number of companies. This raises an old, search engine, problem in a new form: discovery mechanisms of WS are not efficient both in response times and quality of results. In this context, if appropriate solutions are not considered, "traditional" WS discovery mechanisms that consist of scanning all the registries would for instance slow down the increase rate of WS. In this thesis, we are interested in WS discovery in a distributed registry environment. To do this, we first propose to organize a registries network into communities based on functionalities offered by the WS of a registry. Then, to handle the dynamic nature of communities and their members, we define the needed management mechanisms to monitor changes and reconcile potential conflicts. Finally, we propose an approach for WS registries discovery that uses two filters to limit the search space. We first use the functional requirement of a service requester to select the appropriate registry community. Then we use the requester's non-functional requirements and his behavior to select the registries. The proposed solutions were tested by setting up a P2P network of registry communities, implementing a community manager and a discovery system.
284

On-Chip Memory Architecture Exploration Of Embedded System On Chip

Kumar, T S Rajesh 09 1900 (has links)
Today’s feature-rich multimedia products require embedded system solution with complex System-on-Chip (SoC) to meet market expectations of high performance at low cost and lower energy consumption. SoCs are complex designs with multiple embedded processors, memory subsystems, and application specific peripherals. The memory architecture of embedded SoCs strongly influences the area, power and performance of the entire system. Further, the memory subsystem constitutes a major part (typically up to 70%) of the silicon area for the current day SoC. The on-chip memory organization of embedded processors varies widely from one SoC to another, depending on the application and market segment for which the SoC is deployed. There is a wide variety of choices available for the embedded designers, starting from simple on-chip SPRAM based architecture to more complex cache-SPRAM based hybrid architecture. The performance of a memory architecture also depends on how the data variables of the application are placed in the memory. There are multiple data layouts for each memory architecture that are efficient from a power and performance viewpoint. Further, the designer would be interested in multiple optimal design points to address various market segments. Hence a memory architecture exploration for an embedded system involves evaluating a large design space in the order of 100,000 of design points and each design points having several tens of thousands of data layouts. Due to its large impact on system performance parameters, the memory architecture is often hand-crafted by experienced designers exploring a very small subset of this design space. The vast memory design space prohibits any possibility for a manual analysis. In this work, we propose an automated framework for on-chip memory architecture exploration. Our proposed framework integrates memory architecture exploration and data layout to search the design space efficiently. While the memory exploration selects specific memory architectures, the data layout efficiently maps the given application on to the memory architecture under consideration and thus helps in evaluating the memory architecture. The proposed memory exploration framework works at both logical and physical memory architecture level. Our work addresses on-chip memory architecture for DSP processors that is organized as multiple memory banks, with each back can be a single/dual port banks and with non-uniform bank sizes. Further, our work also address memory architecture exploration for on-chip memory architectures that is SPRAM and cache based. Our proposed method is based on multi-objective Genetic Algorithm based and outputs several hundred Pareto-optimal design solutions that are interesting from a area, power and performance viewpoints within a few hours of running on a standard desktop configuration.
285

Kohlenstoffumsatz in aggregierten Böden bestimmt mit Hilfe der natürlichen 13C Abundanz / Carbon turnover in aggregated soils determined by natural 13C abundance

John, Bettina Maria 27 June 2003 (has links)
No description available.
286

Estudo da viabilidade do desenvolvimento de sistemas integrados baseados em redes em chip sem processadores: sistema IPNoSys / The study of viability of development of no processor integrated system based on network-on-chip: IPNoSys system

Ara?jo, S?lvio Roberto Fernandes de 11 April 2008 (has links)
Made available in DSpace on 2014-12-17T15:47:45Z (GMT). No. of bitstreams: 1 SilvioRFA.pdf: 3522539 bytes, checksum: 0e7ac6eda46a29d5f5968d779986fb03 (MD5) Previous issue date: 2008-04-11 / The increase of capacity to integrate transistors permitted to develop completed systems, with several components, in single chip, they are called SoC (System-on-Chip). However, the interconnection subsystem cans influence the scalability of SoCs, like buses, or can be an ad hoc solution, like bus hierarchy. Thus, the ideal interconnection subsystem to SoCs is the Network-on-Chip (NoC). The NoCs permit to use simultaneous point-to-point channels between components and they can be reused in other projects. However, the NoCs can raise the complexity of project, the area in chip and the dissipated power. Thus, it is necessary or to modify the way how to use them or to change the development paradigm. Thus, a system based on NoC is proposed, where the applications are described through packages and performed in each router between source and destination, without traditional processors. To perform applications, independent of number of instructions and of the NoC dimensions, it was developed the spiral complement algorithm, which finds other destination until all instructions has been performed. Therefore, the objective is to study the viability of development that system, denominated IPNoSys system. In this study, it was developed a tool in SystemC, using accurate cycle, to simulate the system that performs applications, which was implemented in a package description language, also developed to this study. Through the simulation tool, several result were obtained that could be used to evaluate the system performance. The methodology used to describe the application corresponds to transform the high level application in data-flow graph that become one or more packages. This methodology was used in three applications: a counter, DCT-2D and float add. The counter was used to evaluate a deadlock solution and to perform parallel application. The DCT was used to compare to STORM platform. Finally, the float add aimed to evaluate the efficiency of the software routine to perform a unimplemented hardware instruction. The results from simulation confirm the viability of development of IPNoSys system. They showed that is possible to perform application described in packages, sequentially or parallelly, without interruptions caused by deadlock, and also showed that the execution time of IPNoSys is more efficient than the STORM platform / O aumento na capacidade de integra??o de transistores permitiu o desenvolvimento de sistemas completos, com in?meros componentes, dentro de um ?nico chip, s?o os chamados SoCs (System-on-Chip). No entanto, o subsistema de interconex?o utilizado pode limitar a escalabilidade dos SoCs, como os barramentos, ou ser uma solu??o ad hoc, como a hierarquia de barramentos. Desse modo, a solu??o ideal para interconex?o no SoCs s?o as redes em chip ou NoCs (Network-on-Chip). As NoCs permitem m?ltiplas conex?o ponto-a-ponto entre os componente e podem ser reusadas em projetos diversos. Entretanto, o uso de NoCs pode representar o aumento na complexidade do projeto do sistema, da ?rea em chip e/ou pot?ncia dissipada. Dessa forma, ? necess?rio ampliar o horizonte de utiliza??o dos sistemas ou quebrar o paradigma do seu desenvolvimento. Assim, ? proposto um sistema baseado em uma NoC, onde as aplica??es s?o descritas em forma de pacotes e executadas de roteador em roteador durante o percurso entre origem e destino dos pacotes, sem a necessidade do uso de processadores convencionais. Para permitir a execu??o de aplica??es, independente do n?mero de instru??es e das dimens?es da rede, foi desenvolvido o algoritmo spiral complement, que permite re-rotear pacotes at? que todas as instru??es contidas nele sejam executadas. Portanto, o objetivo desse trabalho foi estudar a viabilidade do desenvolvimento de tal sistema, denominado sistema IPNoSys. Nesse estudo, foi desenvolvida em SystemC, com precis?o de ciclo, uma ferramenta para simula??o do sistema, a qual permite executar aplica??es implementadas na linguagem de descri??o de pacotes, tamb?m desenvolvida para esse fim. Atrav?s da ferramenta podem ser obtidos diversos resultados que permitem avaliar o funcionamento e desempenho do sistema. A metodologia empregada para descri??o das aplica??es corresponde, a priori, em obter o grafo de fluxo de dados da aplica??o em alto n?vel, e desse grafo descrev?-la em um ou mais pacotes. Utilizando essa metodologia, foram realizados tr?s estudos de casos: contador, DCT-2D e adi??o de ponto flutuante. O contador foi usado para avaliar a capacidade do sistema em tratar situa??es de deadlock e executar aplica??es em paralelo. A DCT-2D foi utilizada para realizar compara??es com a plataforma STORM. E, finalmente, a adi??o de ponto flutuante teve como objetivo ser usada como rotina de tratamento de uma instru??o n?o implementada em hardware. Os resultados de simula??o apontam favoravelmente com rela??o ? viabilidade do desenvolvimento do sistema IPNoSys. Mostrando que ? poss?vel executar aplica??es em forma de pacotes, inclusive paralelamente, sem interrup??es provocadas por eventuais deadlocks, e ainda indicam maior efici?ncia do sistema IPNoSys a respeito do tempo de execu??o comparada a plataforma STORM
287

Système de mesure d'impédance électrique embarqué, application aux batteries Li-ion / Study of a battery monitoring system for electric vehicle, application for Li-ion batteries

Nazer, Rouba Al 24 January 2014 (has links)
La mesure d'impédance électrique en embarqué sur véhicule est un sujet clé pour améliorer les fonctions de diagnostic d'un pack batterie. On cherche en particulier à fournir ainsi des mesures supplémentaires à celles du courant pack et des tensions cellules, afin d'enrichir les indicateurs de vieillissement dans un premier temps, et d'état de santé et de charge dans un second temps. Une méthode classique de laboratoire pour obtenir des mesures d'impédance d'une batterie est la spectroscopie d'impédance électrochimique (ou EIS). Elle consiste à envoyer un signal sinusoïdal en courant (ou tension) de fréquence variable balayant une gamme de fréquences d'intérêt et mesurer ensuite la réponse en tension (ou courant) pour chaque fréquence. Une technique d'identification active basée sur l'utilisation des signaux large bande à motifs carrés est proposée. En particulier, des simulations ont permis de comparer les performances d'identification de différents signaux d'excitation fréquemment utilisés dans le domaine de l'identification et de vérifier les conditions correspondant à un comportement linéaire et invariant dans le temps de l'élément électrochimique. L'évaluation de la qualité d'estimation est effectuée en utilisant une grandeur spécifique : la cohérence. Cette grandeur statistique permet de déterminer un intervalle de confiance sur le module et la phase de l'impédance estimée. Elle permet de sélectionner la gamme de fréquence où la batterie respecte les hypothèses imposées par la méthode d'identification large bande. Afin de valider les résultats, une électronique de test a été conçue. Les résultats expérimentaux permettent de mettre en valeur l'intérêt de cette approche par motifs carrés. Un circuit de référence est utilisé afin d'évaluer les performances en métrologie des méthodes. L'étude expérimentale est ensuite poursuivie sur une batterie Li-ion soumise à un courant de polarisation et à différents états de charge. Des essais comparatifs avec l'EIS sont réalisés. Le cahier de charge établi à l'aide d'un simulateur de batterie Li-ion a permis d'évaluer les performances de la technique large bande proposée et de structurer son utilité pour l'estimation des états de vieillissement et de charge. / Embedded electrical impedance measurement is a key issue to enhance battery monitoring and diagnostic in a vehicle. It provides additional measures to those of the pack's current and cell's voltage to enrich the aging's indicators in a first time, and the battery states in a second time. A classical method for battery impedance measurements is the electrochemical impedance spectroscopy (EIS). At each frequency, a sinusoidal signal current (or voltage) of a variable frequency sweeping a range of frequencies of interest is at the input of the battery and the output is the measured voltage response (or current). An active identification technique based on the use of wideband signals composed of square patterns is proposed. Particularly, simulations were used to compare the performance of different excitation signals commonly used for system identification in several domains and to verify the linear and time invariant behavior for the electrochemical element. The evaluation of the estimation performance is performed using a specific quantity: the spectral coherence. This statistical value is used to give a confidence interval for the module and the phase of the estimated impedance. It allows the selection of the frequency range where the battery respects the assumptions imposed by the non-parametric identification method. To experimentally validate the previous results, an electronic test bench was designed. Experimental results are used to evaluate the wideband frequency impedance identification. A reference circuit is first used to evaluate the performance of the used methodology. Experimentations are then done on a Li–ion battery. Comparative tests with EIS are realized. The specifications are established using a simulator of Li-ion battery. They are used to evaluate the performance of the proposed wide band identification method and fix its usefulness for the battery states estimation: the state of charge and the state of health.
288

Zkoumání modelu pracovní spokojenosti/nespokojenosti - jeho kognitivní, afektivní a behaviorální komponenty (s důrazem na charakteristiky osobnosti) / Exploration of Job Satisfaction - Cognitive, Affective and Behavioral Components (with Focus on Personality Aspects)

Půda, Ivo January 2016 (has links)
Exploration of job satisfaction - cognitive, affective and behavioral components (With focus on personality aspects) PhD theses abstract Charles University in Prague Faculty of Arts Department of psychology Author Ivo Půda MA Supervisor PhDr. David Michalík PhD. February 2016 Abstract Dissertation examines the cognitive, affective and behavioral components of job satisfaction with emphasis on the psychological characteristics of personality. It monitors important trends in relation to this issue (economic cycles, emergence of new generations, pressure on performance and innovation, introduction of technology and data analytics, defending of his/her own position, changes in organization of work), provides an overview of the theories of job satisfaction and reflects the historical development of various theoretical and practical approaches trying to describe the complex relationship of personality, work and experience. For better orientation it monitors the development of two strong paradigms (dispositional and situational), which gradually merges into an interactive approach. Mapping psychological characteristics, which undeniably moderating job satisfaction (neuroticism, extroversion, conscientiousness, positive and negative affectivity, locus of control, emotional stability, defensive tendencies,...
289

Burnout, work engagement and sense of coherence in female academics at two tertiary education institutions in South Africa

Bezuidenhout, Adéle 11 1900 (has links)
Female academics in higher education institutions face numerous challenges in the continuously ch~nging landscape of South African Higher Education. Numerous mergers between different institutions, increasing job demands, ever increasing class sizes and the unique demands of role conflict, inherent to the female role, contribute to the manifestation of stress and burnout (80) in this population group. The research is conducted from a salutogenic paradigm, seeking to find ways of avoiding the negative consequences of 80 and contributing towards the positive experience of Work Engagement (WE) for the female academic. The research also explores the effect of the individual academics' Sense of Cohrence (SOC) on the experience of BO and WE. The research is quantitative in nature. A psychometric instrument was sent to all the permanently employed female academics employed by Unisa and TUT, measuring their levels of 80, WE and SOC. The completed questionnaires were statisticaily analysed. The findings included average levels of 80, with definite signs that the experience of 80 is on the increase. The Cy sub-dimension of BO showed increased levels. The WE scores of the female academics were just above average. The SOC scores of the female academics were low. The main recommendations were that University management need to take cognisance of the symptoms of BO that are present in this population. Strategies need to be put in place to address these issues and the experience of WE need to be treasured and grown through definite actions from Management. Female academics also need to take personal responsibility for their own wellness and act on the initial signs of 80, rather than dismissing it as mere tiredness or lack of energy. There are also a number of recommendations on actions to be taken to experience WE in the academic work that the population undertake on a daily basis / Industrial and Organizational Psychology / D.Litt. et Phil. (Industrial & Organizational psychology)
290

Estimativa do estado de carga de baterias em robôs móveis autônomos / Battery state of charge estimation in autonomous mobile robots

Marcelo Manoel de Oliveira 19 April 2013 (has links)
Cada vez mais robôs móveis autônomos estão sendo utilizados em diversas tarefas e em ambientes com elevado risco para atividades humanas que a paralisação de suas atividades podem gerar outros riscos, perdas e elevados custos. Assim, o estado de carga (SOC) de sistemas de baterias em robôs móveis autônomos é um parâmetro importante na prevenção de uma falha primária nessa aplicação, a ausência de energia. Este trabalho apresenta os métodos existentes na literatura para a determinação do estado de carga de baterias e as tecnologias de baterias disponíveis utilizadas em robôs móveis autônomos ou veículos autônomos guiados. A partir desses estudos foi desenvolvido um modelo de medida, baseado no modelo combinado e foram realizados testes de bancadas para levantamento dos parâmetros e características de três modelos de células de baterias: Lítio Polímero (Li-PO), Níquel-Cádmio (NiCd) e Lítio-Ferro-Polímero (LiFePO4). Com esses parâmetros, aplicou-se o método de estimativa de carga baseado na técnica do Filtro de Kalman Estendido (EKF). Através dos testes, analisou-se comparativamente a resposta do método proposto e a resposta do método OCV e a capacidade de carga real. / Autonomous mobile robots have being increasingly used in various tasks, environments and activities of high risk to human that the stoppage of its activities may generate other risks, losses and high costs. Thus the state of charge (SOC) of battery systems in autonomous mobile robots, is an important parameter to prevent a primary failure in this application, the lack of energy. The paper presents the existing methods in the literature to determine the battery state of charge and battery commercial technologies available used in an autonomous mobile robot or autonomous guided vehicle, from these studies a measurement model based on combined model was developed and testing benches for three cells models on Lithium Polymer Battery (Li-PO), Nickel Cadmium (NiCd) and lithium-iron-Polymer (LiFePO4) batteries were performed for lifting the parameters and apply the battery state of charge method based on the Extended Kalman Filter (EKF) technique. The tests were analyzed in order to observe the comparatively response of the proposed method, the OCV method and Real charge capacity.

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