[pt] A determinação de componentes da gasolina, e a contribuição destes na qualidade e desempenho final, tem levado há um grande número de estudos que possam criar rotinas para o monitoramento deste combustível. O objetivo deste trabalho é identificar e quantificar os principais grupos de compostos que compõem a gasolina comercial distribuída em parte da região sudeste, através de análise multivariada de dados de espectroscopia FT-Raman, através de regressão por Mínimos Quadrados Parciais (PLS - Partial Least Squares) e utilizando à análise dos componentes principais (PCA). Foram utilizadas 120 amostras aleatórias, do laboratório de combustíveis da PUC-Rio no período de janeiro a junho de 2004, as quais fazem parte do programa de controle de combustível. Todas as amostras foram submetidas à análise por cromatografia gasosa (CG) e espectroscopia FT-Raman no mesmo dia. Foram coletados todos os espectros FTRaman, e foram determinados a concentração dos principais grupos componentes da composição das gasolinas comerciais pelo método PONA/PEONA para parafinas(P), olefinas(O), naftênicos(N), aromáticos(A) e etanol(E). Os dados obtidos foram tratados por PLS/PCA de modo a se obter uma correlação de cada região específica dos espectros FT-Raman com os resultados obtidos por CG através dos métodos PONA/PEONA. / [en] The determination of the gasoline components, and the contribution of these in the quality and final performance, had in the past a great number of studies that can create routines for the monitoramento of this fuel. The objective of this work is to identify and to quantify the main groups of composites that compose the distributed commercial gasoline in part of the Southeastern region, through multivaried analysis of data of FT-Raman spectroscopy, through regression for Squared Minimums Partial (PLS - Partial Least Squares) using for the analysis of the main components (PCA), 120 random samples of the fuel laboratory of PUC-Rio in the period of January the June of 2004, which is part of the program of fuel control. All the samples had been submitted to the analysis for gaseous chromatography (GC) and FT-Raman spectroscopy in the same day. The FTRaman spectra had been all collected, and had been determined the concentration of the main component groups of the composition of the commercial gasolinas for method PONA/PEONA for paraffin(P), olefin(O), naphthene(N), aromatic(A) and ethanol(E). The experimental data had been treated by PLS/PCA in order to get a correlation of each specific region of the FT-Raman spectra with the results giving for GC through methods PONA/PEONA.

La régression Partial Least Squares (PLS), de part ses caractéristiques, est devenue une méthodologie statistique de choix pour le traitement de jeux de données issus d’études génomiques. La fiabilité de la régression PLS et de certaines de ses extensions repose, entre autres, sur une détermination robuste d’un hyperparamètre, le nombre de composantes. Une telle détermination reste un objectif important à ce jour, aucun critère existant ne pouvant être considéré comme globalement satisfaisant. Nous avons ainsi élaboré un nouveau critère de choix pour la sélection du nombre de composantes PLS basé sur la technique du bootstrap et caractérisé notamment par une forte stabilité. Nous avons ensuite pu l’adapter et l’utiliser à des fins de développement et d’amélioration de procédés de sélection de prédicteurs significatifs, ouvrant ainsi la voie à une identification rendue plus fiable et robuste des probe sets impliqués dans la caractéristique étudiée d’une pathologie. / The Partial Least Squares (PLS) regression, through its properties, has become a versatile statistic methodology for the analysis of genomic datasets.The reliability of the PLS regression and some of its extensions relies on a robust determination of a tuning parameter, the number of components. Such a determination is still a major aim since no existing criterion could be considered as a global benchmark one in the state-of-art literature. We developed a new bootstrap based stopping criterion in PLS components construction that guarantee a high level of stability. We then adapted and used it to develop and improve variable selection processes, allowing a more reliable and robust determination of significant probe sets related to the studied feature of a pathology.

La digestion anaérobie est un des piliers de l'économie circulaire européenne, produisant du méthane et des engrais organiques à partir de déchets. Le développement de ce secteur passe par la co-digestion et l’optimisation de l'alimentation des procédés. Cela nécessite l'estimation de l'état biologique du digesteur, la caractérisation du substrat ainsi que l’utilisation de modèles prédictifs simulant les performances du digesteur, pour lesquels les solutions actuelles ne sont pas adaptées. Dans cette thèse, un capteur titrimétrique couplant pH et conductivité électrique pour l'estimation des concentrations en acides gras volatils, carbone inorganique et azote ammoniacale a été conçu, améliorant la précision d'estimation des acides gras volatils de 14,5 par rapport aux capteurs actuels. Couplé à l’analyse du biogaz, il permet d'estimer l'état biologique du procédé. En parallèle, une analyse spectroscopique proche-infrarouge, estimant les teneurs en glucides, protéines, lipides, demande chimique en oxygène, rendement et cinétique de production de méthane a été développée réduisant le temps de caractérisation des substrats à quelques minutes. La caractérisation rapide des substrats est utilisée pour implémenter le modèle de digestion anaérobie ADM1 de l’IWA qui prédit les performances d'un digesteur dans des conditions de digestion optimales. Le couplage de l’estimation de l'état biologique à cette approche permet de corriger la prédiction en prenant en compte l'état actuel du digesteur. Cette approche fournit un outil prédictif puissant pour le contrôle avancé des unités de digestion anaérobie ainsi que l'optimisation de la recette d'alimentation. / Anaerobic digestion is an important pillar of the European circular economy, producing methane and organic fertilizers from waste. The development of the anaerobic digestion sector goes through co-digestion and feeding strategy optimization. Its development requires the biological state estimation of the plant, substrate characterization and predictive models simulating the plant performances, for which current solutions are not suitable. In this thesis, a titration sensor coupling pH and electrical conductivity for the estimation of volatile fatty acids, inorganic carbon and ammonia has been designed, improving the accuracy on volatile fatty acids estimation by 14.5 compared to current sensors. Along with biogas analyses, it allows estimating the biological state of the unit. Besides, fast near infrared spectroscopic analysis, estimating in a matter of minute carbohydrate, protein and lipid contents, chemical oxygen demand, methane production yield and kinetics, has been developed. Thus fast substrate characterization is then used to implement a modified Anaerobic Digestion Model n°1 which predicts the performances of a plant under optimal condition. Coupling biological state estimation to this approach enables to correct the prediction with the current state of the plant. This approach provides a powerful predictive tool for advanced control of anaerobic digestion plants and feeding strategy optimization.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-04T11:42:55Z No. of bitstreams: 1 lucasmattosduarte.pdf: 5057896 bytes, checksum: 88e28729f13cbca6707f5e2ea8222e2c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T15:50:51Z (GMT) No. of bitstreams: 1 lucasmattosduarte.pdf: 5057896 bytes, checksum: 88e28729f13cbca6707f5e2ea8222e2c (MD5) / Made available in DSpace on 2016-01-25T15:50:51Z (GMT). No. of bitstreams: 1 lucasmattosduarte.pdf: 5057896 bytes, checksum: 88e28729f13cbca6707f5e2ea8222e2c (MD5) Previous issue date: 2015-03-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O desenvolvimento de metodologias de análise que sejam rápidas, robustas e de baixo custo é um dos grandes focos da química analítica moderna. A aplicação de técnicas espectroscópicas associadas à modelagens multivariadas, com o intuito de realizar inferências quantitativas, vem apresentando grande crescimento ao longo dos últimos anos. O presente trabalho visa o desenvolvimento de metodologias analíticas, por meio da aplicação de diferentes técnicas espectroscópicas, aliadas à regressão por Mínimos Quadrados Parciais (PLS), para duas aplicações diferentes. A primeira consiste na determinação de algumas propriedades físico-químicas de petróleo e a segunda na determinação da concentração de quatro edulcorantes artificiais em amostras de adoçantes de mesa. Em relação ao petróleo, este é formado basicamente por diferentes famílias de hidrocarbonetos, apresentando uma enorme gama de compostos. A composição complexa da matriz faz com que sua avaliação envolva um grande número de análises físico-químicas, o que torna sua caracterização de alto custo e demorada, podendo chegar a um ano. Nessa primeira parte, foram construídos modelos de PLS a partir de dados de Ressonância Magnética Nuclear para o núcleo de Hidrogênio (1H-RMN), para determinar as propriedades gravidade API, resíduo de carbono (RC) e temperatura inicial de aparecimento de cristais (TIAC), além de simular a curva de temperaturas de ebulição para as frações destiladas (SimDis). As curvas obtidas por essa metodologia foram chamadas de “curva de Pontos de Ebulição Estimadas por Quimiometria (PEEQ)”. Na segunda parte do trabalho, foram construídos modelos multivariados pela aplicação de PLS aos dados de espectroscopia Raman e de Infravermelho Próximo (NIR), para quantificação de Aspartame (ASP), Ciclamato (CIC), Sacarina (SAC) e Acesulfame-K (ACSK), em amostra de adoçante de mesa em pó. Para tanto, o método de referência utilizado para fornecer a informação de concentração referentes aos analitos, foi a Cromatografia Líquida com detecção por Espectrometria de Massas (LC-MS). Os modelos de NIR-PLS foram mais eficazes na previsão de ASP, CIC e SAC, enquanto o modelo de Raman-PLS respondeu melhor para o ACSK. Todos os modelos, pra ambas as partes, foram avaliados com base nos seguintes parâmetros de modelagem: número de Variáveis Latentes (LVs), Coeficiente de Correlação para a Validação Cruzada e para Previsão (R2vc e R2p, respectivamente), Raiz quadrada do Erro Quadrático Médio para Validação Cruzada e para Previsão (RMSECV e RMSEP, respectivamente). Por fim, os resíduos de cada modelo construído foram submetidos a testes estatísticos para avaliação de erros sistemáticos e erros de tendência. / The development of analytical methods that are fast, robust and low cost is one of the major focuses of modern analytical chemistry in order to perform quantitative inferences. The application of spectroscopic techniques associated with multivariate modeling has shown significant growth over the last years. This work aims at the development of analytical methodologies, by application of different spectroscopic techniques combined with regression by Partial Least Squares (PLS), for two different applications. The former involves the determination of some physicochemical properties of crude oil and the latter the determination of concentration of four artificial sweeteners in solid tabletop sweeteners samples. Petroleum is basically formed by different hydrocarbons families with a huge range of compounds. Due to the complex composition of the matrix a large number of high costs and time-consuming physicochemical analyses are required. In this first part, PLS models were built from 1H Nuclear Magnetic Resonance data (1H-RMN), in order to determine the following properties: API gravity, Carbon Residue (CR), Wax Appearance Temperature (WAT) and Simulated Distillation (SimDis). The curves obtained by this methodology were called Boiling Points Estimated by Chemometrics (BPEC). In the second part of this work, multivariate models were built by the application of PLS algorithm to Raman spectroscopy data and Near Infrared (NIR) spectroscopy to quantify Aspartame (ASP), Cyclamate (CIC), Saccharin (SAC) and Acesulfame-K (ACSK) in tabletop sweetener powder forms. Therefore, the reference method used to provide information regarding the concentration of analytes was the Liquid Chromatography coupled with Mass Spectrometry (LC-MS). The NIR-PLS models were more effective for the prediction of ASP, CIC and SAC, while Raman-PLS model presented better results to ACSK. All models, for both studies, were evaluated based on the following modelling parameters: number of Latent Variables (LVs), correlation coefficient for Cross Validation and Prediction (R2vc and R2p, respectively), Root Mean Square Error for Cross Validation and Prediction (RMSECV and RMSEP, respectively). Finally, the residuals of each model built were submitted to statistical tests for evaluation of systematic errors and tendency errors.

Les distributeurs se caractérisent désormais comme de véritables marques qui cherchent à construire leur capital pour délivrer davantage de valeur aux consommateurs et ainsi tenter de les satisfaire, de les fidéliser et finalement d'améliorer leur performance. Si de nombreuses recherches académiques et managériales insistent sur la pertinence pour les entreprises de développer leur capital-marque, d'autres investigations rappellent la complexité dune telle tâche et les nombreuses difficultés afférentes à la mesure. Le distributeur n'échappe pas à cette complexité, pis encore, les spécificités de la distribution et les comportements des consommateurs dans ce secteur requièrent davantage de précaution dans l'application du concept aux firmes de distribution. L'objectif de ce travail porte donc sur la définition, la conceptualisation et la mesure du capital-marque du distributeur. Pour ce faire, une analyse qualitative exploratoire est tout d'abord menée afin de compléter la revue de littérature, d'explorer les perceptions et comportements des consommateurs et de faire émerger les variables d'action du distributeur grâce auxquelles il peut générer de la valeur. Afin de pallier aux insuffisances théoriques et de proposer un outil opérationnel aux managers, un cadre conceptuel du capital-marque adapté au distributeur est ensuite construit sur la complémentarité des apports de la littérature et de l'étude exploratoire. Puis le test empirique de ce modèle, par l'usage d'un questionnaire administré auprès de 313 consommateurs et d'une analyse avec l'approche PLS, permet de confirmer le cadre conceptuel défini. Enfin, la discussion des résultats suggèrent que les distributeurs peuvent construire leur marque sur huit dimensions distinctes qu'elles soient relatives aux produits vendus, aux points de vente ou aux expériences de magasinage des consommateurs. Plus spécifiquement, l'apparence du magasin et la qualité des produits contribuent le plus fortement à la création de valeur / Nowadays, retailers must be considered as real and unique brands that wish to build their equity. By enhancing the value offered to consumers, they can retain and attract them and consequently, increase their own performance. However, the brand equity measure is complex and many specificities arise from the retail area that clearly call for a specific conceptualization. The aim of this research is to define, conceptualize and measure the equity of the retailer as a brand. In that respect, an exploratory qualitative research is conducted to firstly, obtain a better understanding of consumers' perceptions and behaviors and secondly, to identify the variables the retailer can leverage to build its equity. Then, a new conceptual framework is established. It includes eight variables related to the product assortment, the outlet or the consumer experience. The model is estimated by using a survey based upon 313 consumer responses and the PLS path modeling approach. The results provide evidence that retailers can build their equity on these eight dimensions. More specifically, the outlet interior appearance and the product quality are the two main drivers of retailer brand equity

O presente trabalho pretende entender a dinâmica do gerenciamento de projetos no IPEN. Para tal, decidiu-se pela pesquisa junto a literatura acadêmica de modelos que pudessem servir de base e que após modificações e ajustes pudessem refletir a realidade dos projetos de Institutos Públicos Pesquisa & Desenvolvimento. Após tratamento estatístico dos dados algumas hipóteses foram validadas e demonstraram sua influência positiva no desempenho do gerenciamento do projeto, tais como a influência das pessoas que compõem as equipes, o efeito da liderança, dentre outras. O modelo, inclusive mostrou-se válido para explicar quais fatores são relevantes para o sucesso dos projetos. Um das principais objetivos, foi exatamente o uso de modelo de avaliação de gestão projetos, que fossem passíveis de validação estatística, e não utilizar um dos disponíveis no mercado, tais como P3M3 e OPM3, para que houvesse um controle e confirmação estatística dos resultados. Outro objetivo foi utilizar um modelo cujas assertivas refletissem a natureza dos projetos de Pesquisa & Desenvolvimento gerenciados pelos pesquisadores do IPEN. Aliás, as referidas assertivas foram formuladas, e enviadas via pesquisa web, e respondidas por praticamente uma centena de profissionais do IPEN, envolvidos com projetos de P&D. A presente dissertação, acrescida das recomendações, ao final, tem como proposta servir de contribuição para os trabalhos desenvolvidos pelo Escritório de Projetos do IPEN. O modelo de avaliação, contido neste trabalho, pode ser aplicado em outras Instituições de P&D brasileiras, para que avaliem a forma e a maneira como gerenciam os seus respectivos projetos. / This paper aims to understand the dynamics involved in the project management at IPEN. To reach this goal, the method chosen was research along with academic literature of models that could serve as a base that after modifications and adjustments could reflect the reality of projects from the Public Institute of Research & Development. After undergoing statistical treatment of the data, some hypotheses were validated and showed positive influence on the project management performance, such as the influence of people who make up the teams, the leadership effect, among others. In fact, the model was found to be valid in explaining which factors are relevant for the success of the projects. One of the main goals was exactly the use of the project management evaluation model, submitted to statistical validation and not to use one available on the market, such as the P3M3 and OPM3, in order to assure the statistical control and confirmation of the results. Another goal was to use a model whose statements reflected the nature of the Research & Development project managed by researchers at IPEN. In fact, the aforementioned statements were formulated and sent via a web survey and answered by almost one hundred IPEN professionals who work on R&D projects. The following dissertation, along with the recommendations at the end, was included to serve as contribution to work developed by the IPEN Project Offices. The evaluation model included in this paper can be applied in other R&D organizations in Brazil, to evaluate the way their projects are managed.

O presente trabalho pretende entender a dinâmica do gerenciamento de projetos no IPEN. Para tal, decidiu-se pela pesquisa junto a literatura acadêmica de modelos que pudessem servir de base e que após modificações e ajustes pudessem refletir a realidade dos projetos de Institutos Públicos Pesquisa & Desenvolvimento. Após tratamento estatístico dos dados algumas hipóteses foram validadas e demonstraram sua influência positiva no desempenho do gerenciamento do projeto, tais como a influência das pessoas que compõem as equipes, o efeito da liderança, dentre outras. O modelo, inclusive mostrou-se válido para explicar quais fatores são relevantes para o sucesso dos projetos. Um das principais objetivos, foi exatamente o uso de modelo de avaliação de gestão projetos, que fossem passíveis de validação estatística, e não utilizar um dos disponíveis no mercado, tais como P3M3 e OPM3, para que houvesse um controle e confirmação estatística dos resultados. Outro objetivo foi utilizar um modelo cujas assertivas refletissem a natureza dos projetos de Pesquisa & Desenvolvimento gerenciados pelos pesquisadores do IPEN. Aliás, as referidas assertivas foram formuladas, e enviadas via pesquisa web, e respondidas por praticamente uma centena de profissionais do IPEN, envolvidos com projetos de P&D. A presente dissertação, acrescida das recomendações, ao final, tem como proposta servir de contribuição para os trabalhos desenvolvidos pelo Escritório de Projetos do IPEN. O modelo de avaliação, contido neste trabalho, pode ser aplicado em outras Instituições de P&D brasileiras, para que avaliem a forma e a maneira como gerenciam os seus respectivos projetos. / This paper aims to understand the dynamics involved in the project management at IPEN. To reach this goal, the method chosen was research along with academic literature of models that could serve as a base that after modifications and adjustments could reflect the reality of projects from the Public Institute of Research & Development. After undergoing statistical treatment of the data, some hypotheses were validated and showed positive influence on the project management performance, such as the influence of people who make up the teams, the leadership effect, among others. In fact, the model was found to be valid in explaining which factors are relevant for the success of the projects. One of the main goals was exactly the use of the project management evaluation model, submitted to statistical validation and not to use one available on the market, such as the P3M3 and OPM3, in order to assure the statistical control and confirmation of the results. Another goal was to use a model whose statements reflected the nature of the Research & Development project managed by researchers at IPEN. In fact, the aforementioned statements were formulated and sent via a web survey and answered by almost one hundred IPEN professionals who work on R&D projects. The following dissertation, along with the recommendations at the end, was included to serve as contribution to work developed by the IPEN Project Offices. The evaluation model included in this paper can be applied in other R&D organizations in Brazil, to evaluate the way their projects are managed.

L'huile d'olive est un élément important de l'alimentation méditerranéenne. Cependant lorsqu'une huile vieillit, elle se dégrade et perd ses propriétés. Il est donc important de connaitre l'évolution de la composition de l'huile en fonction de ses conditions de stockage et de fabrication. Ce suivi a été effectué sur deux huiles de fabrication différente, une huile fruité vert et une huile fruité noir, obtenue à partir d'olive à maturité que l'on a laissé fermenter quelques jours. De manière à obtenir rapidement des vieillissements poussés, ces deux huiles ont été vieillies artificiellement, par procédé thermique , et par procédé photochimique. Ces vieillissements ont été réalisés sur des volumes différents de manière à déterminer l'impact du rapport surface/masse. En parallèle, des échantillons de chacune des deux huiles ont été conservés durant 24 mois dans des conditions de stockage différentes déterminées à l'aide d'un plan d'expériences. Les paramètres influençant le plus la conservation de l'huile d'olive sont l'apport en oxygène, la luminosité et la température. Ces influences ont été déterminées à partir du suivi des principaux paramètres de qualité La réponse des plans a permis de mettre en évidence des interactions entre ces différents paramètres. L'analyse de la composition de l'huile ainsi que de tous les critères de qualité demande beaucoup de temps et consomme une grande quantité de solvant. Afin de pallier à ces désagréments, les résultats ont également été utilisés pour construire des modèles chimiométriques permettant de déterminer ces grandeurs à partir des spectres proche et moyen infrarouge des échantillons. / Olive oil is an important component of the Mediterranean diet. When oil ages, it deteriorates and loses its properties. It is therefore important to know the evolution of the oil composition according to the conditions of storage and manufacturing. This monitoring was carried out on two different oils manufacturing, green fruity oil obtained from olives harvested before maturity, and black fruit oil obtained from olives harvest at maturity and fermented for few days under controlled conditions. To obtain quickly pushed aging, these two oils were artificially aged by heat process (heated to 180 °C under supply of O2), and photochemical process (under an UV lamp and under supply of O2). These aging were performed on different volumes to determine the impact of surface/weight ratio. In parallel, samples of both oils were stored for 24 months under different storage conditions determined using an experimental design. The parameters affecting the most the conservation of olive oil are oxygen, light and temperature. These influences were determined from the monitoring of key quality criteria. Response of experimental design helped to highlight the interactions between these different parameters. The analysis of the oil composition as well as all the quality criteria requires a large amount of solvents and a lot of time consumer. To overcome these inconveniences, chemometric models has been built to determine these criteria from the near and mid-infrared spectra of samples. Natural aging is very little advanced in comparison to accelerated aging, so predictive models were established from the results of natural aging and accelerated separately.

L'objectif de cette thèse est de caractériser les phénomènes d'oxydation de lubrifiants pétroliers et les produits lourds du pétrole. Dans les deux thématiques « lubrifiants » et «lourds pétroliers », une étude de veille stratégique a été effectuée en préalable des études analytiques et chimométriques dans ce cadre le paramètre temps est important. Il nous permet de comprendre les évolutions des domaines, leurs actualités et leur(s) pertinence(s) en précisant si ces domaines sont déjà en phase technologique et utilisation industrielle ou encore en phase de développement. Les huiles lubrifiantes doivent répondre à certaines exigences afin d'optimiser leur performance lors de l'utilisation dans le moteur. Dans ce travail, divers composés soufrés sont testés afin de déterminer le potentiel antioxydant. Deux huiles de base et sept additifs sont testés. Il apparaît que les composés soufrés avec des longues chaînes aliphatiques augmentent la résistance de l'huile, quelle que soit sa nature. Les fiouls lourds utilisés pour les moteurs de bateau peuvent être considérés comme un déchet de raffinage. Néanmoins, la spécification de ces produits est très stricte notamment pour la combustion, la stabilité et la teneur en soufre. Leurs caractérisations nécessitent l'analyse de diverses propriétés, qui sont essentielles pour le contrôle et le développement de technologies de moteurs d'entraînement. L'utilisation d'un support de diffusion permet de s'affranchir des problèmes de nettoyage de cuve couramment rencontrées. / The objective of this thesis is to characterize the phenomena of oxidation of oil lubricants and the heavy products of petroleum. In both themes « lubricating » and « Heavy Fuel Oil », a study of strategic monitoring was performed before analytical and chemometrics studies in this frame the parameter time is important. It helps us to understand changes domains, their news and their relevance and whether these domains are already in industrial use and technological phase or development stage scientific research. Lubricating oils must meet certain requirements in order to optimize their performance when operating in the engine. In this work various types of sulfur compounds are tested to identify the antioxidant potential. Two base oils and seven additives are tested. It appears that sulfur compounds with long aliphatic chains increases resistance of oil, whatever its nature. Heavy fuel oil used for boat motors can be considered as refining waste. Nevertheless the most stringent specification as burning, stability and sulfur content. Their characterizations require the analysis of various properties, which are essential for driving control and the development of engine technologies. The use of a diffusing support allows to free itself from problems of tank cleaning usually met. The aim of this work is to analyze fuel on the boat at the entrance of the engine in order to increase the motor performances and decrease the pollutants by a near infrared miniaturized sensor.

La prédominance de l’informel dans l’économie d’Haïti, où plus de 80% de la population vit en dessous du seuil de la pauvreté et plus de 35% au chômage, laisse entrevoir des liens étroits entre l’économie informelle, la pauvreté et le marché du travail. Faire ressortir ces interrelations, exige une évaluation de cette économie informelle qui fait l’objet des quatre chapitres de notre thèse traitant successivement l’évolution de la situation macroéconomique, le capital humain, les gains des travailleurs informels, et la segmentation du marché du travail.Le premier chapitre fait un diagnostic du phénomène selon l’état des lieux des théories élaborées et l’évolution du cadre macro-économique d’Haïti de 1980 à 2010 et propose une évaluation macroéconomique de l’informel à partir d’un modèle PLS (Partial Least Squares) en pourcentage du PIB.Le chapitre deux établit les relations entre l’évolution de l’économie informelle, dérégulation et politiques néolibérales grâce à un modèle LISREL (Linear Structural Relations). Nous examinons les incidences des politiques fiscales, budgétaires et monétaires des 30 dernières années sur l’économie informelle. Nous réévaluons aussi les causes de l’évolution de l’informel généralement évoquées par les études empiriques (taxes, sécurité sociale).Au chapitre trois, nous analysons la dimension micro-réelle de l’informel grâce à un modèle des gains à la Mincer estimé par les équations logit à partir des données d’une enquête nationale sur l’emploi et l’économie informelle (EEEI) de 2007. Nous analysons les déterminants des gains informels au regard de la position des travailleurs sur le marché (salariés, entrepreneurs et indépendants) ; et les revenus (formels et informels) et les caractéristiques socioéconomiques des travailleurs pauvres et non-pauvres par rapport au seuil de pauvreté.Au chapitre quatre, nous testons d’abord la compétitivité et la segmentation du marché de l’emploi en faisant usage de modèle de Roy et du modèle de Roy élargi à travers une estimation d’un modèle Tobit. Nous utilisons un modèle de Processus de Dirichlet : d’abord analyser la segmentation et la compétitivité éventuelle du marché du travail informel ainsi que ses déterminants, selon les données de l’EEEI-2007 ; ensuite, pour distinguer les caractéristiques fondamentales des informels involontaires (exclus du marché du travail formel) de celles des informels volontaires qui en retirent des avantages comparatifs. / The predominance of the informal sector in the economy of Haiti, where more than 80% of the population lives below the threshold of poverty and more than 35% unemployed, suggests links between the informal economy, poverty and the labour market. Highlight these interrelationships, requires an assessment of the informal economy, which is the subject of the four chapters of this thesis, dealing successively with the evolution of the macroeconomic situation, human capital, the informal earnings of workers, and the segmentation of the labour market.The first chapter made a diagnosis of the phenomenon according to the State of affairs of the developed theories and the evolution of the macroeconomic framework of Haiti from 1980 to 2010. And then offers a macroeconomic assessment of the informal sector as a percentage of GDP from a PLS (Partial Least Squares).Chapter two sets out the relationship between the evolution of the informal economy, deregulation and neo-liberal policies through a LISREL (Linear Structural Relations) model. We look at the impact of the budgetary, fiscal and monetary policies of the past 30 years on the informal economy. We also reassess the causes of the evolution of the informal economy generally evoked by the empirical studies (taxes, social security).In the chapter three, we analyse the micro-real dimension of the informal economy through a model of the Mincer earnings estimated by the equations logit from data in a national survey on employment and the informal economy (EEEI) in 2007. We analyse the determinants of informal gains in terms of the position of the market workers (employees, entrepreneurs and self-employed); and revenues (formal and informal) and the socio-economic characteristics of the working poor and non-poor compared to the poverty line.In chapter four, we first test the competitiveness and the segmentation of the labour market by making use of model of Roy and the expanded Roy model through an estimate a model Tobit. We use a model of Dirichlet process: first analyse the segmentation and possible informal work and market competitiveness as its determinants, according to data from the EEEI 2007; then, to distinguish the fundamental characteristics of the involuntary informal (excluded from the formal labour market) than the voluntary informal who gain comparative advantages.