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Experimental study and modeling of methane hydrates cristallization under flow from emulsions with variable fraction of water and anti-agglomerant / Étude expérimentale et modélisation de la cristallisation d'hydrates de méthane en écoulement à partir d'une émulsion à pourcentages variables d'eau et d’anti-agglomérantMendes Melchuna, Aline 04 January 2016 (has links)
La cristallisation des hydrates pendant la production de pétrole est une source de risques, surtout liés au bouchage des lignes de production dû à l’agglomération des hydrates. Pendant l'extraction de pétrole, l'huile et l'eau circulent dans le pipeline et forment une émulsion instable. La phase eau se combine avec les composants d'hydrocarbures légers et peut former des hydrates. La cristallisation des hydrates a été intensivement étudiée, principalement à faible fraction d’eau. Cependant, lorsque le champ de pétrole devient mature, la fraction d’eau augmente et peut devenir la phase dominante, un système peu étudié concernant à la formation d'hydrates. Plusieurs techniques peuvent être combinées pour éviter ou remédier la formation d'hydrates. Récemment, une nouvelle classe d'additifs a commencé à être étudiée : Inhibiteurs d'Hydrates à Bas Dosage (LDHI), divisés en Inhibiteurs Cinétiques (KHI-LDHI) et anti-agglomérants (AA-LDHI).Ce travail est une étude paramétrique de la formation d'hydrates à partir de l'émulsion, en variant la fraction d’eau, le débit, en absence et en présence d’AA-LDHI. Les expériences ont été réalisées sur la boucle d'écoulement Archimède, qui est en mesure de reproduire les conditions de la mer profonde. L'objectif de cette étude est d'améliorer la compréhension de la formation d'hydrate et de comprendre comment l'additif dispersant évite l'agglomération. Pour ce faire, un modèle comportemental de la cristallisation pour les systèmes sans et avec additif a été développé. Il a également été proposé une technique pour déterminer la phase continue du système et un mécanisme d'action pour l'anti-agglomérant a été suggéré. / Crystallization of hydrates during oil production is a major source of hazards, mainly related to flow lines plugging after hydrate agglomeration. During the petroleum extraction, oil and water circulate in the flow line, forming an unstable emulsion. The water phase in combination with light hydrocarbon components can form hydrates. The crystallization of hydrates has been extensively studied, mainly at low water content systems. However, as the oil field matures, the water fraction increases and can become the dominant phase, a system less known in what concerns hydrate formation. Actually, several techniques can be combined to avoid or remediate hydrate formation. Recently, a new class of additives called Low Dosage Hydrate Inhibitor (LDHI) started to be studied, they are classified as Kinetic Hydrate Inhibitors (KHI-LDHI) and Anti-Agglomerants (AA-LDHI).This work is a parametric study about hydrate formation from emulsion systems ranging from low to high water content, where different flow rates and the anti-agglomerant presence were investigated. The experiments were performed at the Archimède flow loop, which is able to reproduce deep sea conditions. The goal of this study is enhancing the knowledge in hydrate formation and comprehending how the dispersant additive acts to avoid agglomeration. For this matter, it was developed a crystallization topological model for the systems without and with additive. A technique to determine the system continuous phase and a mechanism of the anti-agglomerant action from the chord length measurements were also proposed.
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The Drivers of Team-based Inside Sales Performance at Different Stages of the Sales Pipeline.Haque, Rahat 09 August 2019 (has links)
There is a lack of academic research on sales teams, despite team selling becoming more prominent in recent years. Particularly in Inside Sales, there is a lack of clarity as to what are the drivers of optimum team-based selling and their degree of effect on sales performance. We utilize a team-based approach that aims to study the characteristics of Inside Sales teams and their interactions with business leads, using data from a well-reputed leads management software vendor. Based on prior team-based constructs in the literature, we built a framework that posits Quality of Team Composition, Task Utility and Intra-team Coordination leading to different categories of sales performance at various stages of the sales pipeline via their reflective variables.
We tested our conceptual model in the following fashion: first, we used text mining on sales results to classify the different stages of the sales pipeline. Following that, we measured the conversion ratio at each stage as appropriate. Next, we discretized each conversion ratio into three levels of performance groups. The outcome variables in the model are different categories of team performance at each stage of the sales pipeline. Subsequently, we used multinomial logistic regression to regress our outcome variables on our team-based predictor variables in the hopes of establishing and validating important drivers for nuanced Inside Sales success.
We uncovered new insight regarding team-selling best practices, using pre-identified constructs from the literature which are uniquely suited to teams and also constructs which are aggregated at a team level from an individual level. Our study is especially relevant to the Inside Sales process, as the outcome measures relate to the sales pipeline. Our main finding was that in there is a difference in skills required at different stages of the sales pipeline, in that more customization and experience is needed at the more advanced stages, whereas more repetition of activity is needed at the beginner stages. We also found that smaller team sizes tend to do better in Inside Sales, which was an unsettled research question in team research with plenty of evidence in favor of both smaller and bigger teams.
Additionally, even if it was not a primary goal of our study, by virtue of classifying the leads by their final outcomes, we stumbled across an interesting finding, which is that an overwhelming majority of the sales leads tend to stay at one stage in their entire lifecycle. The implications of all our findings are very relevant to both practitioners and researchers of Inside Sales who are interested in team-based sales optimization. More research should be done in the field of Industrial Marketing, building upon what we found to be true for the B2B sector.
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To Curve or Not to Curve? The Effect of College Science Grading Policies on Implicit Theories of Intelligence, Perceived Classroom Goal Structures, and Self-efficacyHaley, James January 2015 (has links)
Thesis advisor: George M. Barnett / There is currently a shortage of students graduating with STEM (science, technology, engineering, or mathematics) degrees, particularly women and students of color. Approximately half of students who begin a STEM major eventually switch out. Many switchers cite the competitiveness, grading curves, and weed-out culture of introductory STEM classes as reasons for the switch. Variables known to influence resilience include a student's implicit theory of intelligence and achievement goal orientation. Incremental theory (belief that intelligence is malleable) and mastery goals (pursuit of increased competence) are more adaptive in challenging classroom contexts. This dissertation investigates the role that college science grading policies and messages about the importance of effort play in shaping both implicit theories and achievement goal orientation. College students (N = 425) were randomly assigned to read one of three grading scenarios: (1) a "mastery" scenario, which used criterion-referenced grading, permitted tests to be retaken, and included a strong effort message; (2) a "norm" scenario, which used norm-referenced grading (grading on the curve); or (3) an "effort" scenario, which combined a strong effort message with the norm-referenced policies. The dependent variables included implicit theories of intelligence, perceived classroom goal structure, and self-efficacy. A different sample of students (N = 15) were randomly assigned a scenario to read, asked to verbalize their thoughts, and responded to questions in a semi-structured interview. Results showed that students reading the mastery scenario were more likely to endorse an incremental theory of intelligence, perceived greater mastery goal structure, and had higher self-efficacy. The effort message had no effect on self-efficacy, implicit theory, and most of the goal structure measures. The interviews revealed that it was the retake policy in the mastery scenario and the competitive atmosphere in the norm-referenced scenarios that were likely driving the results. Competitive grading policies appear to be incompatible with mastery goals, cooperative learning, and a belief in the efficacy of effort. Implications for college STEM instruction are discussed. / Thesis (PhD) — Boston College, 2015. / Submitted to: Boston College. Lynch School of Education. / Discipline: Teacher Education, Special Education, Curriculum and Instruction.
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Modelling of wax deposition in sub-sea pipelinesBryan, Stephen Hugh January 2016 (has links)
A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering, 2016 / Wax deposition in sub-sea pipelines is a major concern in the oil industry. Wax precipitates in a pipeline when the temperature falls below a certain temperature called the Wax Appearance Temperature. As wax precipitates and deposits in a pipeline, the wax deposit can cause oil flow problems and reduce production efficiency. At critical conditions wax deposits in pipelines may damage production equipment or cause a production stoppage.
In the past two or three decades, the challenge has been to develop and apply high-fidelity models for wax deposition. In this context, two promising models have recently been developed: that of Eskin et al. (2014) and that of Haj-Shafiei et al. (2014). This research report tries to solve and elucidate some of the key assumptions of these wax deposition models, through implementing them in the Python Programming Language.
In investigating the significance of the shape of the Solubility Curve on wax deposition, a concave shaped solubility curve was found to exhibit the highest average deposition and the convex shaped solubility curve the lowest average deposition. The shape of the solubility curve also drastically affects the peak wax height with a concave shaped solubility curve forming the greatest wax peak.
The results have shown that the description of the phenomenon of Wax deposition in undersea pipelines is difficult to grasp for anyone not familiar with the topic because of the complexity of the mechanisms involved. Often, the models are difficult to visualise owing to their multi-dimensional solution procedure and the interdependence of parameters. The resultant programs could be utilised to help illustrate the process of Wax deposition to Engineering students or professionals who do not have access to expensive proprietary software or who are less proficient with programming but interested in the field. / GS2016
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Tarifação na malha de gasodutos de transporte no Brasil: evolução e perspectivas / Tariff Policy on Gas Pipeline Network in Brazil: Developments and ProspectsPinto, Raul Penazzo 28 March 2014 (has links)
Este estudo analisa a indústria de gás natural de modo a contribuir para o melhor entendimento acerca das políticas tarifárias da atividade de transporte de gás natural conduzidas pelo governo sob a ótica de um programa de expansão da malha de gasodutos e de fortalecimento da indústria de gás natural no país. A adoção de mecanismos que possibilitem a separação e abertura das parcelas que compõem o preço de venda do gás natural visa a proporcionar uma maior modicidade tarifária, reduzindo os subsídios cruzados entre os Estados (regiões produtoras frente a distantes centros consumidores) e ampliando a eficiência econômica na utilização da malha de gasodutos do sistema de transporte. A partir do auxílio das teorias e modelos tarifários empregados nas indústrias de infraestrutura de rede, a pesquisa analisa a evolução da regulação tarifária associada à Parcela de Produto (Parcela Variável) e à Parcela de Transporte (Parcela Fixa) na formação do preço de venda do gás natural de origem nacional entre a Petrobras e as concessionárias estaduais de distribuição de gás canalizado. A análise dos resultados permite observar que a introdução de mudanças na sistemática de formação do preço de venda do gás natural provoca um retrocesso em relação à transparência na estrutura tarifária e na comercialização do gás natural. A atual política tarifária e os descontos (aproximadamente 32%) praticados pela Petrobras nos preços de venda para as distribuidoras das regiões Nordeste e Sudeste provocam alterações significativas não apenas na competitividade do gás natural frente aos demais combustíveis, mas também dentro do próprio mercado de gás natural. Os consumidores de gás natural nacional não detêm a informação acerca do quanto pagam no custo de serviço de transporte, diferente dos consumidores de gás natural de origem boliviana que se deparam com regras contratuais claras de reajustes dos componentes de cada parcela. Assim, averigua-se que essas mudanças penalizam principalmente os estados com maior produção de gás natural (Rio de Janeiro, Espírito Santo, Bahia e Sergipe), uma vez que o Fator Distância não se encontra claramente definido na nova fórmula de preços do gás nacional. Ainda, conclui-se que o marco regulatório da indústria de gás natural define de maneira clara a formação da tarifa de transporte para os novos gasodutos, enquanto a ANP ainda estuda maneiras de incluir na regulamentação a transparência tarifária na malha de gasodutos existentes. / This study analyzes the natural gas industry in order to contribute to a better understanding of the pricing policies of the activity of the natural gas transmission conducted by the government from the perspective of a program to expand the pipeline network and strengthen the natural gas industry in the country. The adoption of mechanisms that allow the separation and opening of the parcels that make up the selling price of natural gas is intended to provide greater low tariffs, reducing cross-subsidies between states (producing regions across the distant consuming centers) and increasing economic efficiency the use of the gas pipeline of the transportation system. From the aid of tariff models and theories employed in the network infrastructure industries, the research analyzes the evolution of tariff regulation associated with the portion of product (Variable Parcel) and Parcel Transportation (Fixed Parcel) in the formation of the selling price of domestic natural gas rise between Petrobras and the state distribution utilities of gas. The analysis allows us to observe that the introduction of systematic changes in the training of the sales price of natural gas causes a regression in relation to transparency in pricing structure and marketing of natural gas. The current pricing policy and (approximately 32 %) discounts offered by Petrobras in selling prices to distributors in the Northeast and Southeast regions cause significant changes not only the competitiveness of natural gas compared to other fuels , but also within the gas market itself natural. Consumers of domestic natural gas does not hold the information about how much they pay the cost of shipping service, different consumers of natural gas from Bolivian origin faced with clear rules of contractual adjustments of the components of each plot. Thus, it ascertains that these changes mainly penalize states with higher natural gas production (Rio de Janeiro, Espírito Santo, Bahia and Sergipe), since the distance factor is not clearly defined in the new pricing formula of the national gas. Still, it is concluded that the regulatory framework of the natural gas industry defines clearly the formation of the transport charge for new pipelines, while the ANP is also considering ways to include the tariff transparency in the regulatory network of existing pipelines.
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Estabilidade linear para intermitência severa em sistemas água-ar. / Linear stability for severe slugging in air-water systems.Azevedo, Gabriel Romualdo de 15 December 2017 (has links)
Apresenta-se um modelo matemático que avalia numericamente a estabilidade do estado estacionário para escoamentos água-ar em sistemas pipeline-riser de geometria variável. Uma análise a partir da teoria de estabilidade linear é aplicada a um modelo matemático adequado ao escoamento água-ar no sistema pipeline-riser. O modelo considera equações de continuidade para a fase líquida e para a fase gasosa, admite-se escoamento unidimensional e em condição isotérmica. O líquido é considerado incompressível enquanto que a fase gasosa é considerada um gás ideal. Admite-se uma equação de momento simplificada para mistura onde despreza-se a inércia (NPW - Modelo No Pressure Wave) e o padrão de escoamento local é definido com base nas condições do escoamento e na inclinação local. Assim, a intermitência severa é controlada principalmente pela gravidade no riser e pela compressibilidade do gás no pipeline. Tanto a correlação de fluxo de deriva quanto o cálculo da queda de pressão por atrito, adotados como lei de fechamento do modelo, são determinados em função do padrão de escoamento. Injeção de gás e válvula de choke são consideradas, respectivamente, na base e no topo do riser. O modelo é aplicado à sistemas pipeline-riser com escoamento água-ar citados na literatura. Os resultados da análise de estabilidade linear numérica são comparados aos resultados experimentais e numéricos apresentando uma excelente concordância. / A mathematical model that numerically evaluates the stability of the stationary state for hilly terrain air-water flows systems is presented. Numerical linear stability analysis is performed to a suitable mathematical model for the two-phase flows in a pipeline-riser system. The mathematical model considers the continuity equations for the liquid and gas phases, one-dimensional flow and isothermal conditions. The liquid is assumed incompressible while the gas phase is considered as an ideal gas. A simplified momentum equation for the mixture, neglecting inertia (NPW - No pressure wave model) is considered and the local flow pattern is defined based on the flow conditions and the local inclination. In this way, severe slugging is controlled mainly by gravity in the riser and compressibility in the pipeline. The void fraction and friction pressure drop, utilized as closure laws, are determined based on the local flow pattern. Gas injection at the bottom of the riser and a choke valve at the top are considered. The model is applied to air-water pipeline-riser systems reported in the literature. Numerical linear stability analysis results are compared with experimental and numerical results reported in the literature with excellent agreement.
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Avaliação dos problemas ambientais relacionados aos aspectos geológico-geotécnicos e dutos enterrados, poliduto Osbra: trecho Porto Ferreira - Ribeirão Preto / Evaluation of environmental problems related to the geological-geotechnical aspects and buried pipeline, pipeline OSBRA: link Porto Ferreira and Ribeirão PretoFerreira, Joseli 27 July 1999 (has links)
Vazamentos decorrentes de acidentes envolvendo dutos constituem uma fonte potencial de contaminação das águas subsuperficiais, superficiais e dos componentes dos meios físico e biológico, em geral. Neste trabalho são analisados os problemas ambientais decorrentes de possíveis vazamentos dos produtos transportados no poliduto OSBRA, no trecho situado entre Porto Ferreira e Ribeirão Preto (SP). Este trecho está localizado em uma área de intensa ocupação agrícola, atravessando extensa área de recarga da Formação Botucatu e de basaltos fraturados pertencentes à Formação Serra Geral, além de vários canais de drenagem. Todas estas áreas estão, portanto, sujeitas à contaminação em caso de acidentes envolvendo o duto. Neste trabalho são apontados os principais agentes deflagadores de possíveis acidentes no trecho e analisados os diferentes contextos de contaminação de acordo com as características do meio físico e do produto liberado. / Leakage from pipeline constitute a potential source of groundwater and surface water contamination as well as to geological and biological environment components. In this research the environmental problems due to leaking of petroleum products transported by OSBRA pipeline, which runs between Porto Ferreira and Ribeirão Preto (SP), are analyzed. It is located in an area of intense agricultural management, crossing large and recharge area of Botucatu Formation and fractured basaltic rocks from Serra Geral Formation. All these areas are, therefore, subject to the contamination in case of accidents involving the pipeline. The aim of this research is to analyze the agents responsible by the accidents and to determine the different types of contamination according to the main characteristic of the environment and spill material.
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Modelagem da velocidade crítica de transporte de polpas minerais contendo partículas grossas. / Modeling critical velocity of transport for mineral slurries with coarse particles.Pinto, Thiago César de Souza 29 May 2012 (has links)
O dimensionamento de sistemas de transporte hidráulico de polpas minerais exige especial atenção à medida que partículas grossas apresentam um comportamento de sedimentação no interior dos tubos. Dentro desta situação, a velocidade de transporte da polpa mineral deve ter magnitude suficiente para suspender e transportar os sólidos, evitando que os mesmos se depositem na base da tubulação. O bombeamento de polpas minerais em tubos horizontais contendo partículas grossas constituiu o objeto desta tese. Um levantamento sobre a literatura corrente foi realizado e, através de procedimentos experimentais, obteve-se um banco de dados para o modelamento da velocidade crítica (VC), isto é, a velocidade mínima em que ocorre a formação de um leito móvel na base do tubo, apresentando magnitude ligeiramente superior à velocidade de deposição VD, caracterizada pelo início da deposição das partículas na base dos dutos. Para a realização dos ensaios, foram construídas duas unidades experimentais de bombeamento de polpa mineral, onde foram estudadas as seguintes variáveis: i) gradiente de pressão por metro de tubo horizontal (\'delta\'P/L), ii) velocidade média do fluxo (V), iii) perfil de concentração de sólidos ao longo da seção transversal, iv) fator de forma através da função de esfericidade das partículas (\'psi\'), v) densidade do sólido e do líquido, vi) concentração volumétrica dapolpa mineral, vii) granulometria dos sólidos e viii) diâmetro da tubulação. A primeira unidade experimental foi montada com tubulação em PVC transparente de diâmetro interno de 25,4mm e a segunda unidade foi construída em PVC branco com um trecho de 2m em acrílico transparente, apresentando diâmetro interno de 50,8mm. A velocidade critica (VC) para cada condição estudada foi determinada visualmente, através das seções transparentes da tubulação. As amostras utilizadas neste trabalho foram: concentrados de apatita e hematita e o mineral quartzo. As frações granulométricas estudadas foram inseridas em duas classes de tamanho, sendo a primeira classe passante em 297µm e retida em 249µm e a segunda classe passante em 149µm e retida em 105µm. Os resultados permitiram determinar um novo modelo semiempírico para VC, alcançando desvios menores que 10% para as velocidades preditas em relação aos valores de velocidades observadas experimentalmente. / The design of hydraulic systems of slurry transport demands a special attention due to coarse particles present a settling behavior inside the pipes. In this situation, the transport velocity should have order of magnitude sufficient to promote the suspension and the transport of particles, avoiding the solids deposition at the bottom of pipe. The transport of mineral slurries containing coarse particles was the primary goal of the thesis. A survey of the available literature was done and through the experimental tests could be possible to raise a data bank in order to develop a new best fit correlation for the critical velocity (VC) which included the particle shape effect, through the sphericity function. VC could be defined as the minimum velocity where a moving bed of particles takes place at the bottom of the horizontal pipe and it is slightly above the deposition velocity VD, which could be characterized by a bed of stationary particles at the bottom of pipe. The research was conducted using two recirculating pipe test rigs with transparent PVC pipe of 25.4mm and 50.8mm internal diameter with slurry concentrations from 8% up to 27% by volume. The material used was apatite and hematite concentrates and quartz mineral, clustered in two classes of size range (-0.297+0.210mm; -0.149+0.105mm), where the variables were: i) Head losses per meter of horizontal pipe (\'delta\'P/L), ii) Mean transport velocity (V), iii) solids distribution profile, iv) particle shape effect, through the sphericity function (\'psi\'), v) density of particles and liquid, vi) Volumetric concentration of slurries, vii) particles size and viii) pipe diameter. The critical velocity (VC), for each studied condition, was visually determined through the transparent sections of the pipes. The results have yielded a new semi empirical model to predict the critical velocity, yielding a deviation of less than 10% from the observed values of experimental data for VC.
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Conception architecturale haut débit et sûre de fonctionnement pour les codes correcteurs d'erreurs / Design of high speed and dependable architectures for error correcting codesJaber, Houssein 09 December 2009 (has links)
Les systèmes de communication modernes exigent des débits de plus en plus élevés afin de traiter des volumes d'informations en augmentation constante. Ils doivent être flexibles pour pouvoir gérer des environnements multinormes, et évolutifs pour s'adapter aux normes futures. Pour ces systèmes, la qualité du service (QoS) doit être garantie malgré l'évolution des technologies microélectroniques qui augmente la sensibilité des circuits intégrés aux perturbations externes (impact de particules, perte de l'intégrité du signal, etc.). La tolérance aux fautes devient un critère important pour améliorer la fiabilité et par conséquence la qualité de service. Cette thèse s'inscrit dans la continuité des travaux menés au sein du laboratoire LICM concernant la conception architecturale d'une chaîne de transmission à haut débit, faible coût, et sûre de fonctionnement. Elle porte sur deux axes de recherche principaux : le premier axe porte sur les aspects rapidité et flexibilité, et en particulier sur l'étude et l'implantation d'architectures parallèles-pipelines dédiées aux codeurs convolutifs récursifs. Le principe repose sur l'optimisation des blocs calculant le reste de la division polynomiale qui constitue l'opération critique du codage. Cette approche est généralisée aux filtres récursifs RII. Les caractéristiques architecturales principales recherchées sont une grande flexibilité et une extensibilité aisée, tout en préservant la fonctionnalité ainsi qu'un bon équilibre entre quantité de ressources utilisées (et donc surface consommée) et performances obtenues (vitesse de fonctionnement) ; le deuxième axe de recherche porte sur le développement d'une méthodologie de conception de codeurs sûrs en présence de fautes, améliorant ainsi la tolérance de circuits intégrés numériques. L’approche proposée consiste à ajouter aux codeurs des blocs supplémentaires permettant la détection matérielle en ligne de l'erreur afin d'obtenir des architectures sûrs en présence des fautes. Les solutions proposées permettent d'obtenir un bon compromis entre complexité et fréquence de fonctionnement. Afin d'améliorer encore le débit du fonctionnement, nous proposons également des versions parallèles-pipelines des codeurs sûrs. Différents campagnes d'injection de fautes simples, doubles, et aléatoires ont été réalisées sur les codeurs afin d'évaluer les taux de détection d’erreurs. L'étude architectures sûrs de fonctionnement a ensuite été étendue aux décodeurs parallèles-pipeline pour les codes cycliques en blocs. L'approche choisie repose sur une légère modification des architectures parallèles-pipeline développées / Nowadays, modern communication systems require higher and higher data throughputs to transmit increasing volumes of data. They must be flexible to handle multi-norms environments, and progressive to accommodate future norms. For these systems, quality of service (QoS) must be guaranteed despite the evolution of microelectronics technologies that increase the sensitivity of integrated circuits to external perturbations (impact of particles, loss of signal integrity, etc). Fault-tolerance techniques are becoming more and more an important criteria to improve the dependability and the quality of service. This thesis’work continues previous research undertaken at the LICM laboratory on the architectural design of high-speed, low-cost, and dependable transmission systems. It focuses on two principal areas of research : The first research area concerns the speed and flexibility aspects, particularly on the study and implementation of parallel-pipelined architectures dedicated to recursive convolutional encoders. The principle is based on the optimization of blocks that calculate the remainder of the polynomial division which constitute the critical operation of the encoding. This approach is generalized to recursive IIR filters. The main architectural characteristics being aimed are high flexibility and scalability, yet preserving a good trade-off between the amount of resources used (and hence, area consumption) and the obtained performance (operation speed). The second topic concerns the developing of a methodology for designing FS (fault-secure) encoders, improving the tolerance of digital integrated circuits. The proposed approach consists in adding an extra blocks to the encoders, allowing online error detection. The proposed solutions offer a good compromise between complexity and frequency operation. For even higher throughput, parallel-pipelined implementations of FS encoders were considered. Different fault injection campaigns of single, double, and random errors were applied to the encoders in order to evaluate error detection rates. The study of dependable architecture was extended to pipeline-parallel decoders for cyclic block codes. This approach is based on a slight modification of the parallel-pipeline architectures developed at LICM laboratory, introducing some redundancy in order to make it dependable
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Arquitetura pipeline reconfigurável através de instruções geradas por programação genética para processamento morfológico de imagens digitais utilizando FPGAs / Reconfigurable pipelined architecture through instructions generated by genetic programming for morphological image processing using FPGAsPedrino, Emerson Carlos 27 November 2008 (has links)
A morfologia matemática fornece ferramentas poderosas para a realização de análise de imagens em baixo nível e tem encontrado aplicações em diversas áreas, tais como: visão robótica, inspeção visual, medicina, análise de textura, entre outras. Muitas dessas aplicações requerem processamento em tempo real e para sua execução de forma eficiente freqüentemente é utilizado hardware dedicado. Também, a tarefa de projetar operadores morfológicos manualmente para uma dada aplicação não é trivial na prática. A programação genética, que é um ramo relativamente novo em computação evolucionária, está se consolidando como um método promissor em aplicações envolvendo processamento de imagens digitais. Seu objetivo primordial é descobrir como os computadores podem aprender a resolver problemas sem, no entanto, serem programados para essa tarefa. Essa área ainda não foi muito explorada no contexto de construção automática de operadores morfológicos. Assim, neste trabalho, desenvolve-se e implementa-se uma arquitetura original, de baixo custo, reconfigurável por meio de instruções morfológicas e lógicas geradas automaticamente através de uma aproximação linear baseada em programação genética, visando-se o processamento morfológico de imagens em tempo real utilizando FPGAs de alta complexidade, com objetivos de filtragem, reconhecimento de padrões e emulação de filtros desconhecidos de softwares comerciais, para citar somente algumas aplicações. Exemplos de aplicações práticas envolvendo imagens binárias, em níveis de cinza e coloridas são fornecidos e seus resultados são comparados com outras formas de implementação. / Mathematical morphology supplies powerful tools for low level image analysis, with applications in robotic vision, visual inspection, medicine, texture analysis and many other areas. Many of the mentioned applications require dedicated hardware for real time execution. The task of designing manually morphological operators for a given application isnot always a trivial one. Genetic programming is a relatively new branch of evolutionary computing and it is consolidating as a promising method for applications of digital image processing. The main objective of genetic programming is to discover how computers can learn to solve problems without being programmed for that. In the literature little has been found about the automatic morphological operators construction using genetic programming. In this work, the development of an original reconfigurable architecture using logical and morphological instructions generated automatically by a linear approach based on genetic programming is presented. The developed architecture is based on Field Programmable Gate Arrays (FPGAs) and has among the possible applications, image filtering, pattern recognition and filter emulation. Binary, gray level and color image practical applications using the developed architecture are presented and the results are compared with other implementation techniques.
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