Récemment, il y a eu une hausse massive du trafic dans les réseaux mobiles à cause de nouveaux services et applications. Les architectures actuelles des réseaux cellulaires ne sont plus capables de gérer de façon satisfaisante ce trafic. Les Réseaux de Petites Cellules (RPC), basées sur un déploiement dense de stations de bases portables, autoorganisantes et efficaces en termes d’énergie apparait comme une solution prometteuse à ce problème. Les RPC augmentent la capacité du réseau, réduisent sa consommation énergétique et améliorent sa couverture. Par contre, elles posent des défis importants en termes de design optimal. Dans cette thèse, des aspects liés au design cellulaire et à l’allocation de ressources dans les RPC sont traités. La thèse se compose de deux parties. Dans la première partie, le design cellulaire est étudié : une population statique d’utilisateurs est considérée, et la taille optimale de cellule maximisant le débit spatial est donnée en fonction du modèle de récepteur, des conditions radio et des partitions indoor/outdoor. En considérant des utilisateurs mobiles, la taille de cellule optimale est étudiée afin de minimiser le temps de service, et minimiser le blocage et la déconnexion en cours de communication, en fonction de la vitesse des utilisateurs et du type de trafic. Le problème de placement des stations de base optimal est traité en fonction de différents critères de qualité (maximisation de débit total, équité proportionnelle, minimisation de délai, équité max-min) pour différentes distributions d’utilisateurs et partitions de cellules. Le problème de scaling de capacité dans un RPC limité par l’interférence avec pré-codage est étudié, et la quantité optimale d’antennes par utilisateurs en fonction de l’interférence inter-cellules est dérivée. Dans le cadre d’un réseau “green”, pour une charge du réseau donnée, on étudie les politiques optimales en boucle ouverte, afin de maximiser soit une fonction coût du système (contrôle centralisé) soit des fonctions de coût de chacune des stations de base (contrôle distribué). Dans la seconde partie, nous étudions l’allocation de ressources, nous introduisons les concepts de d’équité T-échelle et équité multi-échelle. Ces concepts permettent de distribuer les ressources équitablement pour les différentes classes de trafic. Ces concepts sont illustrés par des applications au partage de spectre et à l’allocation de ressources dans les femto-cellules indoor/outdoor. L’allocation de puissance pour satisfaire les demandes de trafic des utilisateurs avec un grand nombre d’interféreurs est une tâche difficile. Ce problème est abordé, et nous proposons un algorithme universel qui converge vers une configuration de puissance optimale qui satisfait les demandes des utilisateurs dans toutes les stations de base. Les performances de l’algorithme sont illustrées pour différentes configurations du système et différents niveaux de coopération entre les stations de base. / An ever increasing demand for mobile broadband applications and services is leading to a massive network densification. The current cellular system architectures are both economically and ecologically limited to handle this. The concept of small-cell networks (SCNs) based on the idea of dense deployment of self-organizing; low-cost, low-power base station (BSs) is a promising alternative. Although SCNs have the potential to significantly increase the capacity and coverage of cellular networks while reducing their energy consumption, they pose many new challenges to the optimal system design. Due to small cell sizes, the mobile users cross over many cells during the course of their service resulting in frequent handovers. Also, due to proximity of BSs, users (especially those at cell edges) experience a higher degree of interference from neighboring BSs. If one has to derive advantages from SCNs, these alleviated effects have to be taken care either by compromising on some aspects of optimality (like dedicating extra resources) or by innovating smarter algorithms or by a combination of the two. The concept of umbrella cells is introduced to take care of frequent handovers. Here extra resources are dedicated to ensure that the calls are not dropped within an umbrella cell. To manage interference, one might have to ensure that the neighboring cells always operate in independent channels or design algorithms which work well in interference dominant scenarios or use the backhaul to incorporate BS cooperation techniques. Further, small cell BS are most often battery operated, which calls for efficient power utilization and energy conservation techniques. Also, when deployed in urban areas, some of the small cells can have larger concentration of users throughout the cell, for example, hot-spots, which call in for design of SCNs with dense users. Also, with portable BSs, one has the choice to install them on street infrastructure or within residential complexes. In such cases, cell design and resource allocation has to consider aspects like user density, distribution (indoor/outdoor), mobility, attenuation, etc. We present the thesis in two parts. In the first part we study the cell design aspects, while the second part deals with the resource allocation. While the focus is on SCNs, some of the results derived and the tools and techniques used are also applicable to conventional cellular systems.

Submitted by PPG Ci?ncia da Computa??o (ppgcc@pucrs.br) on 2018-06-15T14:23:09Z No. of bitstreams: 1 LEONARDO REZENDE JURACY_DIS.pdf: 2268947 bytes, checksum: bedc63f7c14296e039a798403cdeec80 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-06-26T12:27:11Z (GMT) No. of bitstreams: 1 LEONARDO REZENDE JURACY_DIS.pdf: 2268947 bytes, checksum: bedc63f7c14296e039a798403cdeec80 (MD5) / Made available in DSpace on 2018-06-26T12:45:06Z (GMT). No. of bitstreams: 1 LEONARDO REZENDE JURACY_DIS.pdf: 2268947 bytes, checksum: bedc63f7c14296e039a798403cdeec80 (MD5) Previous issue date: 2018-03-21 / Atualmente, a abordagem s?ncrona ? a mais utilizada em projeto de circuitos integrados por ser altamente automatizado pelas ferramentas comerciais e por incorporar margens de tempo para garantir o funcionamento correto nos piores cen?rios de varia??es de processo e ambiente, limitando otimiza??es no per?odo do rel?gio e aumentando o consumo de pot?ncia. Por um lado, circuitos ass?ncronos apresentam algumas vantagens em potencial quando comparados com os circuitos s?ncronos, como menor consumo de pot?ncia e maior vaz?o de dados, mas tamb?m podem sofrer com varia??es de processo e ambiente. Por outro lado, circuitos resilientes s?o uma alternativa para manter o circuito funcionando na presen?a de efeitos de varia??o. Sendo assim, foi proposto o circuito Blade que combina as vantagens de circuitos ass?ncronos com circuitos resilientes. Blade utiliza latches em sua implementa??o e mant?m seu desempenho em cen?rios de caso m?dio. Independentemente do estilo de projeto (s?ncrono ou ass?ncrono), durante o processo de fabrica??o de circuitos integrados, algumas imperfei??es podem acontecer, causando defeitos que reduzem o rendimento de fabrica??o. Circuitos defeituosos podem apresentar um comportamento falho, gerando uma sa?da diferente da esperada, devendo ser identificados antes de sua comercializa??o. Metodologias de teste podem ajudar na identifica??o e diagn?stico desse comportamento falho. Projeto visando testabilidade (do ingl?s, Design for Testability - DfT) aumenta a testabilidade do circuito adicionando um grau de controlabilidade e observabilidade atrav?s de diferentes t?cnicas. Scan ? uma t?cnica de DfT que fornece para um equipamento de teste externo acesso aos elementos de mem?ria internos do circuito, permitindo inser??o de padr?es de teste e compara??o da resposta. O objetivo deste trabalho ? propor uma abordagem de DfT estrutural, completamente autom?tica e integrada com as ferramentas comerciais de projeto de circuitos, incluindo uma s?rie de m?todos para lidar com os desafios relacionados ao teste de circuitos ass?ncronos e resilientes, com foco no Blade. O fluxo de DfT proposto ? avaliado usando um m?dulo criptogr?fico e um microprocessador. Os resultados obtidos para o m?dulo criptogr?fico mostram uma cobertura de falha de 98,17% para falhas do tipo stuck-at e 89,37% para falhas do tipo path-delay, com um acr?scimo de ?rea de 112,16%. Os resultados obtidos para o microprocessador mostram uma cobertura de 96,04% para falhas do tipo stuck-at e 99,00% para falhas do tipo path-delay, com um acr?scimo de ?rea de 50,57%. / Nowadays, the synchronous circuits design approach is the most used design method since it is highly automated by commercial computer-aided design (CAD) tools. Synchronous designs incorporate timing margins to ensure the correct behavior under the worstcase scenario of process and environmental variations, limiting its clock period optimization and increasing power consumption. On one hand, asynchronous designs present some potential advantages when compared to synchronous ones, such as less power consumption and more data throughput, but they may also suffer with the process and environmental variations. On the other hand, resilient circuits techniques are an alternative to keep the design working in presence of effects of variability. Thus, Blade template has been proposed, combining the advantages of both asynchronous and resilient circuits. The Blade template employs latches in its implementation and supports average-case circuit performance. Independently of the design style (synchronous or asynchronous), during the fabrication process of integrated circuits, some imperfections can occur, causing defects that reduce the fabrication yield. These defective ICs can present a faulty behavior, which produces an output different from the expected, and it must be identified before the circuit commercialization. Test methodologies help to find and diagnose this faulty behavior. Design for Testability (DfT) increases circuit testability by adding a degree of controllability and observability through different test techniques. Scan design is a DfT technique that provides for an external test equipment the access to the internal memory elements of a circuit, allowing test pattern insertion and response comparison. The goal of this work is to propose a fully integrated and automated structural DfT approach using commercial EDA tools and to propose a series of design methods to address the challenges related to testing asynchronous and resilient designs, with focus on Blade template. The proposed DfT flow is evaluated with a criptocore module and a microprocessor. The obtained results for the criptocore module show a fault coverage of 98.17% for stuck-at fault model and 89.37% for path-delay fault model, with an area overhead of 112.16%. The obtained results for the microprocessor show a fault coverage of 96.04% for stuck-at fault model and 99.00% for path-delay fault model, with an area overhead of 50.57%.

Improvements in performance, reliability and durability as well as reductions in production costs, remain critical prerequisites for the commercialization of proton exchange membrane fuel cells. In this thesis, a computational framework for fuel cell analysis and optimization is presented as an innovative alternative to the time consuming trial-and-error process currently used for fuel cell design. The framework is based on a two-dimensional through-the-channel isothermal, isobaric and single phase membrane electrode assembly (MEA) model. The model input parameters are the manufacturing parameters used to build the MEA: platinum loading, platinum to carbon ratio, electrolyte content and gas diffusion layer porosity. The governing equations of the fuel cell model are solved using Netwon's algorithm and an adaptive finite element method in order to achieve quadratic convergence and a mesh independent solution respectively. The analysis module is used to solve two optimization problems: i) maximize performance; and, ii) maximize performance while minimizing the production cost of the MEA. To solve these problems a gradient-based optimization algorithm is used in conjunction with analytical sensitivities. The presented computational framework is the first attempt in the literature to combine highly efficient analysis and optimization methods to perform optimization in order to tackle large-scale problems. The framework presented is capable of solving a complete MEA optimization problem with state-of-the-art electrode models in approximately 30 minutes. The optimization results show that it is possible to achieve Pt-specific power density for the optimized MEAs of 0.422 $g_{Pt}/kW$. This value is extremely close to the target of 0.4 $g_{Pt}/kW$ for large-scale implementation and demonstrate the potential of using numerical optimization for fuel cell design.

Improvements in performance, reliability and durability as well as reductions in production costs, remain critical prerequisites for the commercialization of proton exchange membrane fuel cells. In this thesis, a computational framework for fuel cell analysis and optimization is presented as an innovative alternative to the time consuming trial-and-error process currently used for fuel cell design. The framework is based on a two-dimensional through-the-channel isothermal, isobaric and single phase membrane electrode assembly (MEA) model. The model input parameters are the manufacturing parameters used to build the MEA: platinum loading, platinum to carbon ratio, electrolyte content and gas diffusion layer porosity. The governing equations of the fuel cell model are solved using Netwon's algorithm and an adaptive finite element method in order to achieve quadratic convergence and a mesh independent solution respectively. The analysis module is used to solve two optimization problems: i) maximize performance; and, ii) maximize performance while minimizing the production cost of the MEA. To solve these problems a gradient-based optimization algorithm is used in conjunction with analytical sensitivities. The presented computational framework is the first attempt in the literature to combine highly efficient analysis and optimization methods to perform optimization in order to tackle large-scale problems. The framework presented is capable of solving a complete MEA optimization problem with state-of-the-art electrode models in approximately 30 minutes. The optimization results show that it is possible to achieve Pt-specific power density for the optimized MEAs of 0.422 $g_{Pt}/kW$. This value is extremely close to the target of 0.4 $g_{Pt}/kW$ for large-scale implementation and demonstrate the potential of using numerical optimization for fuel cell design.

Orientador: Paulo Correa Lima / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T04:02:28Z (GMT). No. of bitstreams: 1 Calado_RobisomDamasceno_M.pdf: 2515663 bytes, checksum: 21c4fbba4a8cbe4ea49b31b3b7a19b49 (MD5) Previous issue date: 2006 / Resumo: A competitividade em mercados globalizados, bem como a inovação e difusão de novas técnicas e métodos, oriundas do Sistema Toyota de Produção e Controle de Qualidade Total, são aplicadas em fábricas de todo o mundo e tem alavancado constante melhoria nos postos de trabalho e considerável redução dos riscos de acidente, pois a segurança está no escopo da melhoria de produtividade e qualidade. Neste trabalho foca-se a eliminação do risco de acidente (problemática específica do objeto de estudo) através da aplicação dos conceitos e ferramentas da manufatura enxuta, como mapeamento do fluxo de valor e célula de manufatura, de forma integrada ao objeto de estudo e seus trabalhadores com uso da metodologia de pesquisa-ação, desta forma foi possível obter resultados qualitativos e aumento da produtividade no processo de injeção e tampografia de peças plásticas, este trabalho pode servir de motivação e fonte de pesquisa para se implementar melhorias nas inúmeras empresas do ramo plástico entre outros segmentos de manufatura de bens de consumo / Abstract: The competitiveness in global markets, as well as the innovation and diffusion of new techniques and methods, original from Toyota Production System and Total Quality Control, are applied in factories worldwide and have provided continuous improvement in workstations and a deep reduction of accident risks, because larger safety is the target of productivity improvement and quality. In this paper focused the elimination of the accident risk (specific problem of the object of study) through the application of the concepts and tools of Lean manufacturing, as Value Stream Mapping and Manufacture Cell, on way integrated the study object and their workers with use of research-action methodology, have been able to obtain qualitative results that can be useful as motivation and research sources for improvements implementation in many companies of plastic activity among other segments of consumption goods production / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

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