Dans le contexte de l’avion plus électrique, les réseaux électriques aéronautiques sont en pleine évolution. Cette évolution est poussée par le besoin d’une intégration à forte densité énergétique ce qui pose des défis aux concepteurs en termes d’architectures, de systèmes et de méthodes de dimensionnement.Un réseau de bord est composé d’un ensemble de systèmes électriques multidisciplinaire qui proviennent de différents fournisseurs dont le design est actuellement effectué en répondant à des standards de qualité spécifiés par l’agrégateur. L’objectif de la thèse est de proposer de nouvelles approches intégrées qui permettent de gérer la complexité des réseaux électriques tout en convergeant vers un résultat optimal, offrant des gains de masses en référence à un design par des « approches mécanistes » reposant sur un agrégat de boucles d’optimisation locales. Une approche multiniveau a été développée en s’inspirant des travaux sur la MDO « Multidisciplinary Design Optimization ». L’élaboration de cette approche a été le résultat d’une expertise accumulée en appliquant différentes méthodes disponibles dans la bibliographie. L’optimisation porte plus spécifiquement sur les filtres d’entrée des charges du réseau ainsi que sur le filtre de sortie du canal de génération du réseau électrique embarqué. L’optimisation multiniveau vise, dans un contexte collaboratif, à itérer entre le niveau agrégateur (niveau réseau) et le niveau équipementier (charges et source du réseau). L’utilisation d’une formulation agrégée au niveau réseau et le respect des causalités au niveau des sous-problèmes sont les principaux atouts de cette approche qui conduit à des solutions proches de l’optimum global de masse de filtres. / Within more electric aircraft context, electric systems and networks have to evolve. High energy density integration pushes designers to reconsider their systems, architectures and tools.An aircraft network contains a large number of multidisciplinary systems which come from different manufacturers. Each manufacturer designs its system separately following quality standards specified by the aggregator. The goal of this thesis is to provide system approaches which could deal with the high-level of complexity of the network while reaching the optimal design of all the system and so reduce the total weight in comparison with mechanistic approaches based on independent optimization loops for the different subsystems.Consulting MDO “Multidisciplinary Design Optimization” researches, we have developed a multilevel approach based on our previous studies and conclusions on classical approaches used in the design of electrical systems. The optimization concerns the input filters of the loads connected to the HVDC bus and the output filter of the generating channel which supply the electric power. The multilevel collaborative optimization allows an automated exchange of data between the aggregator (system level) and manufacturers (sub-system level) and thanks to that, the optimal design of all the system is joined. The strong points of this approach are the aggregated formulation and causality connections between sub-systems.

Modelos algébricos para prever o comprimento de uma chama turbulenta têm sido foco de estudo de diversos grupos de pesquisa por suas aplicações na área de engenharia. O método experimental para obter o modelo varia desde visualizações simples, até técnicas fotográficas, este último com parâmetros fotográficos variando entre os autores. Técnicas fotográficas são usadas para estimar a altura de levantamento da base da chama, (Lift-Off) e o comprimento médio visível de chama (Visible Flame Length, VFL). Duas técnicas comuns que podem ser encontradas na literatura: por imagens de chama com baixo tempo de exposição e longo tempo de exposição, são comparados com um terceiro que se baseia na intensidade luminosa e na frequência de imagens de chama que ocupam um pixel. O melhor método foi utilizado para caracterizar o comportamento das chamas turbulentas de gás natural para diferentes regimes de velocidade do escoamento. Modelos algébricos que preveem o comprimento de chama, altura de levantamento e a velocidade crítica de extinção de chama são avaliados com os novos resultados experimentais. Logo após, os coeficientes numéricos dos melhores modelos algébricos são reajustados Finalmente, foram obtidos mapas de estabilidade relacionados à altura de levantamento e à velocidade crítica de extinção de chama para cada diâmetro em função da diluição com CO2 e do número adimensional de Reynolds. A terceira parte deste trabalho está focada no estudo da distribuição de radiação térmica. Em particular, foram consideradas três distâncias radiais medidas em comprimentos de chama (0,5 Lf, 1 Lf, 2 Lf) visando obter a distribuição do fluxo radiante experimental ao longo de um eixo vertical adjacente às chamas. Finalmente, os dados experimentais foram utilizados como dados de entrada em uma análise inversa com o objetivo de calcular os fatores de ponderação do modelo das múltiplas fontes ponderadas (por suas siglas em inglês WMPS). Nesta última parte, são apresentados frações radiantes e distribuições de fluxo de calor radiante de chamas de gás natural diluídas para diversas diluições com dióxido de carbono e diâmetros do queimador. / Predicting models for turbulent diffusion flame lengths have several applications driven the attention of many research groups. Since several studies use photographs to measure the flame length, with photographic parameters varying among authors, in other cases simple visualizations were used. It is important to explore possible discrepancies among measurement technics that could affect the results. Optical visualizations of turbulent diffusion flames are used to estimate the visible average flame length (VFL) and the lift-off. The study presents a study of three different methods to measure the VFL using optical techniques. The effect on the image of the main optic parameters such as focus, exposure time and ISO sensibility are analyzed. The VFL obtained with images in low exposure time and long exposure time are compared with a third optical method that is based on the luminous intensity and the frequency of flame images occupying a pixel. One method was used to characterize the behavior of turbulent diffusion flames of natural gas for a range of flames in function of the flow velocity. Universal non-dimensional models that describe the VFL, lift-off and the blow-out stability limit of gaseous jet diffusion flames in the still air have been compared with new experimental data. The numerical coefficients of the best models are adjusted. Finally, maps of stability related to lift-off and blow-out were obtained for each diameter in function of the dilution with CO2 and flow exit velocity expressed in non-dimensional Reynolds number The third part of this work focuses on the estimation of the thermal distribution of radiative flux from turbulent diffusion flames in laboratory-scale. The experimental measurements were gotten from the previous stability study. In particular, was considered three radial distances measured in flame lengths (0,5 Lf, 1 Lf, 2 Lf) aiming at obtaining the experimental radiant flux along a vertical axis adjacent to the flames. Finally, the experimental data was used as input data in an inverse analysis with the purpose of computing weight coefficients of the weighted multi-point source (WMPS) model. Then, experimental data that include: radiant fractions and radiative heat flux are presents for several flames with different dilutions with carbon dioxide and burner´s diameters.

Modelos algébricos para prever o comprimento de uma chama turbulenta têm sido foco de estudo de diversos grupos de pesquisa por suas aplicações na área de engenharia. O método experimental para obter o modelo varia desde visualizações simples, até técnicas fotográficas, este último com parâmetros fotográficos variando entre os autores. Técnicas fotográficas são usadas para estimar a altura de levantamento da base da chama, (Lift-Off) e o comprimento médio visível de chama (Visible Flame Length, VFL). Duas técnicas comuns que podem ser encontradas na literatura: por imagens de chama com baixo tempo de exposição e longo tempo de exposição, são comparados com um terceiro que se baseia na intensidade luminosa e na frequência de imagens de chama que ocupam um pixel. O melhor método foi utilizado para caracterizar o comportamento das chamas turbulentas de gás natural para diferentes regimes de velocidade do escoamento. Modelos algébricos que preveem o comprimento de chama, altura de levantamento e a velocidade crítica de extinção de chama são avaliados com os novos resultados experimentais. Logo após, os coeficientes numéricos dos melhores modelos algébricos são reajustados Finalmente, foram obtidos mapas de estabilidade relacionados à altura de levantamento e à velocidade crítica de extinção de chama para cada diâmetro em função da diluição com CO2 e do número adimensional de Reynolds. A terceira parte deste trabalho está focada no estudo da distribuição de radiação térmica. Em particular, foram consideradas três distâncias radiais medidas em comprimentos de chama (0,5 Lf, 1 Lf, 2 Lf) visando obter a distribuição do fluxo radiante experimental ao longo de um eixo vertical adjacente às chamas. Finalmente, os dados experimentais foram utilizados como dados de entrada em uma análise inversa com o objetivo de calcular os fatores de ponderação do modelo das múltiplas fontes ponderadas (por suas siglas em inglês WMPS). Nesta última parte, são apresentados frações radiantes e distribuições de fluxo de calor radiante de chamas de gás natural diluídas para diversas diluições com dióxido de carbono e diâmetros do queimador. / Predicting models for turbulent diffusion flame lengths have several applications driven the attention of many research groups. Since several studies use photographs to measure the flame length, with photographic parameters varying among authors, in other cases simple visualizations were used. It is important to explore possible discrepancies among measurement technics that could affect the results. Optical visualizations of turbulent diffusion flames are used to estimate the visible average flame length (VFL) and the lift-off. The study presents a study of three different methods to measure the VFL using optical techniques. The effect on the image of the main optic parameters such as focus, exposure time and ISO sensibility are analyzed. The VFL obtained with images in low exposure time and long exposure time are compared with a third optical method that is based on the luminous intensity and the frequency of flame images occupying a pixel. One method was used to characterize the behavior of turbulent diffusion flames of natural gas for a range of flames in function of the flow velocity. Universal non-dimensional models that describe the VFL, lift-off and the blow-out stability limit of gaseous jet diffusion flames in the still air have been compared with new experimental data. The numerical coefficients of the best models are adjusted. Finally, maps of stability related to lift-off and blow-out were obtained for each diameter in function of the dilution with CO2 and flow exit velocity expressed in non-dimensional Reynolds number The third part of this work focuses on the estimation of the thermal distribution of radiative flux from turbulent diffusion flames in laboratory-scale. The experimental measurements were gotten from the previous stability study. In particular, was considered three radial distances measured in flame lengths (0,5 Lf, 1 Lf, 2 Lf) aiming at obtaining the experimental radiant flux along a vertical axis adjacent to the flames. Finally, the experimental data was used as input data in an inverse analysis with the purpose of computing weight coefficients of the weighted multi-point source (WMPS) model. Then, experimental data that include: radiant fractions and radiative heat flux are presents for several flames with different dilutions with carbon dioxide and burner´s diameters.

Submitted by Raildo Barros Rodrigues (raildo.barros@gmail.com) on 2018-09-24T15:10:31Z No. of bitstreams: 1 Dissertação_Grade_Horária_Raildo_Marins_Aneirson.pdf: 2926580 bytes, checksum: 6799724ac48abd21caecd50cf5156480 (MD5) / Rejected by Pamella Benevides Gonçalves null (pamella@feg.unesp.br), reason: Solicitamos que realize correções na submissão seguindo as orientações abaixo Verificar formatação com a equipe da biblioteca. Agradecemos a compreensão. on 2018-09-24T18:49:58Z (GMT) / Submitted by Raildo Barros Rodrigues (raildo.barros@gmail.com) on 2018-09-25T16:48:30Z No. of bitstreams: 2 Dissertação_Grade_Horária_Raildo_Marins_Aneirson.pdf: 2926580 bytes, checksum: 6799724ac48abd21caecd50cf5156480 (MD5) Dissertação_Grade_Horária_Raildo_Marins_Aneirson.pdf: 2944631 bytes, checksum: d0f33c161c9cb711a7b75cd2666f0470 (MD5) / Approved for entry into archive by Pamella Benevides Gonçalves null (pamella@feg.unesp.br) on 2018-09-25T18:15:24Z (GMT) No. of bitstreams: 1 rodrigues_rb_me_guara.pdf: 2944631 bytes, checksum: d0f33c161c9cb711a7b75cd2666f0470 (MD5) / Made available in DSpace on 2018-09-25T18:15:24Z (GMT). No. of bitstreams: 1 rodrigues_rb_me_guara.pdf: 2944631 bytes, checksum: d0f33c161c9cb711a7b75cd2666f0470 (MD5) Previous issue date: 2018-09-20 / Outra / Esta dissertação trata da construção de um modelo matemático para a elaboração do quadro de horários dos cursos de graduação do CBV/IFRR. A programação de horários é um problema de otimização combinatória estudado há anos pela Pesquisa Operacional e, em termos de complexidade computacional, é tido como NP-Completo, sendo assim, é um problema que exige grande capacidade de processamento. A elaboração do quadro de horários em qualquer instituição de ensino é complexa e demanda tempo para os responsáveis por essa atividade, pois as necessidades dos professores e alunos devem ser atendidas e devem-se evitar conflitos nos horários dos professores. A instituição estudada nesta dissertação assim como outras instituições, possui particularidades institucionais, dessa forma, uma formulação geral do problema acaba não lhe sendo útil. O CBV/IFRR realiza a elaboração dos horários de forma manual, por meio de planilha eletrônica e realização de reuniões entre os gestores, o que torna difícil encontrar uma solução factível. Sendo assim, foi necessária a realização de pesquisa científica para encontrar métodos que poderiam ser aplicados ao problema. Assim, este trabalho teve como objetivo desenvolver um modelo de Programação Matemática que permitisse a elaboração dos horários para cursos de graduação do CBV/IFRR. Utilizou-se entrevistas com as Coordenações de Cursos para obtenção das informações acerca do problema tratado, tais como restrições e prioridades a serem atendidas com a programação de aulas para professores. Estas informações serviram de base para a construção do modelo conceitual, que foi utilizado para elaboração do modelo matemático final, que foi implementado na linguagem de alto nível GAMS® e resolvido pelo solver CPLEX®. Os testes do modelo foram realizados otimizando uma instância com dados reais da instituição estudada. Os resultados obtidos da otimização foram satisfatórios, pois foi possível encontrar uma solução ótima para a instância em tempo computacional adequado, com todas as restrições, impostas pelas características peculiares do problema tratado, sendo respeitadas e as prioridades estabelecidas pelas Coordenações de Cursos atendidas. / This dissertation deals with the construction of a mathematical model for the elaboration of the timetable of the undergraduate courses of the CBV/IFRR. Time scheduling is a combinatorial optimization problem that has been studied for years by Operational Research and, in terms of computational complexity, is considered as NP-Complete, so it is a problem that requires large processing capacity. The elaboration of the timetable in any educational institution is complex and takes time for those responsible for this activity, because the needs of teachers and students must be met and avoid conflicts in the schedules of teachers. The institution studied in this dissertation as well as other institutions, has institutional features, so a general formulation of the problem ends up being of no use to it. The CBV/IFRR performs the elaboration of the schedules manually, through a spreadsheet and holding meetings between managers, which makes it difficult to find a feasible solution. Thus, it was necessary to carry out scientific research to find methods that could be applied to the problem. Thus, this work had the objective of developing a Mathematical Programming model that allowed the elaboration of the schedules for the undergraduate courses of the CBV/IFRR. We used interviews with the Course Coordinators to obtain information about the problem, such as constraints and priorities to be met with the programming of classes for teachers. This information was the basis for the construction of the conceptual model, which was used to elaborate the final mathematical model, which was implemented in the GAMS® high-level language and solved by the CPLEX® solver. The tests of the model were performed optimizing an instance with real data of the studied institution. The results obtained from the optimization were satisfactory, since it was possible to find an optimal solution for the instance in adequate computational time, with all the restrictions imposed by the peculiar characteristics of the problem, being respected and the priorities established by the Coordination of Courses attended.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-17T20:10:32Z No. of bitstreams: 1 danielrodriguespereira.pdf: 736772 bytes, checksum: d15b2f08bb14ed58ae985f6123258ed5 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-18T13:51:41Z (GMT) No. of bitstreams: 1 danielrodriguespereira.pdf: 736772 bytes, checksum: d15b2f08bb14ed58ae985f6123258ed5 (MD5) / Made available in DSpace on 2017-04-18T13:51:41Z (GMT). No. of bitstreams: 1 danielrodriguespereira.pdf: 736772 bytes, checksum: d15b2f08bb14ed58ae985f6123258ed5 (MD5) Previous issue date: 2017-02-07 / Apresentamos neste trabalho o algoritmo de pontos interiores e direções viáveis denominado FDIPA para resolução de problemas de otimização definido por uma função diferenciável e por restrições de desigualdades. O algoritmo gera uma sequência de pontos interiores a partir de um dado ponto inicial também de interior e converge globalmente com ordem superlinear para um par Karush-Kuhn-Tucker do problema. A cada iteração uma direção de descida da função potencial é calculada inicialmente pela resolução de um sistema nas variáveis dual e primal. Apresentamos também o algoritmo FDA para resolução de problemas de complementaridade definido por uma função diferenciável e não linear. Mostramos a equivalência entre os dois métodos no sentido de gerarem as mesmas direções de descida, viável e de restauração a partir de uma atualização dos multiplicadores de Lagrange do problema de otimização. Realizamos uma comparação entre os métodos em uma coletânea de problemas de complementaridade. / In this work we present the algorithm of internal points and viable directions denominated FDIPA to solve optimization problems defined by a differentiable function and by inequalities restrictions. The algorithm generates a sequence of interior points from a given interior starting point and converges globally with superlinear order to a Karush-Kuhn-Tucker pair of the problem. At each iteration a descent direction of the potential function is calculated initially by the solution of a system in the dual and primal variables. We also present the FDA algorithm to solve complementarity problems defined by a non-linear differentiable function. We show the equivalence between the two methods in the sense that they generate the same descent, feasible and restoring directions from an update to the Lagrange multipliers of the optimization problem. We perform a comparison between the two methods in a collection of complementarity problems.

Cette thèse se positionne au croisement de la théorie de la décision en univers incertain et de la théorie des choix d’investissements irréversibles (options réelles). Elle poursuit trois objectifs principaux :1. Tout d’abord, elle s’inscrit dans un courant de recherche dynamique, notamment en économie et en finance, qui vise à modéliser l’impact de l’ambigüité à laquelle des décideurs sont parfois confrontés lorsqu’ils contemplent des choix aux conséquences irréversibles. 2. Ensuite, elle met l’accent sur la persistance de fortes controverses théoriques portant sur les fondements axiomatiques des modèles de décision face à l’ambigüité. Aussi, nous proposons d’utiliser certaines propriétés des modèles non linéaires pour aborder sous un angle original la représentation de l’ambigüité et des préférences des individus face à celle-ci. En particulier, nous suggérons de ne pas restreindre a priori la nature des préférences individuelles face à l’ambigüité. Pour cela, nous adoptons les fondements de l’approche de Choquet, à savoir tout particulièrement l’emploi de capacités (probabilités non additives) pour pondérer les différentes alternatives ambigües. Tout en proposant ce processus stochastique ambigu, dit Choquet-Brownien, nous soulignons les conditions de l’inévitable arbitrage entre réalisme des hypothèses et souplesse d’utilisation du modèle. D’un point de vue axiomatique, une attention particulière est portée au respect de la cohérence dynamique.3. Enfin, cette thèse vise à encourager une prise en considération plus ambitieuse des sources d’incertitude dans le cadre des options réelles. Alors qu’ils sont présentés comme des outils privilégiés pour affronter le risque, les modèles d’options réelles ont certainement beaucoup à gagner à s’enrichir par la prise en compte également de l’ambigüité. En effet, alors que le risque est largement discuté dans la littérature des options réelles, l’impact de l’ambigüité est très largement ignoré. / The need to elaborate innovative methods to analyze risk and uncertainty has become increasingly obvious over the last decades, especially due the growing perception of the multiplicity of social and economical issues characterized by the weight of uncertainty (natural disasters, ecological risk, financial crises…).This thesis is at the crossroad between decision theory under uncertainty and the irreversible investment theory (real options). Consequently, the main goal of this thesis is three-fold: 1. First, it contributes to the dynamic stream of literature in economics and finance that models the impact of ambiguity that individuals may often face and/or perceive when contemplating irreversible choices.2. Next, this thesis emphasizes that even with the plethora of decision models already dealing with uncertainty, elaborating sound axiomatic foundations largely remains an open question. This leads us to recommending the use of non linear models (such as multiple-priors, Choquet expected utility, robust control, smooth ambiguity), which in turn raises many challenging theoretical and practical obstacles. We explore original ways of addressing some of these issues and suggest the construction of ambiguous stochastic processes in a Choquet expected utility framework (that are called Choquet-Brownian motions): ambiguity preferences are thereby directly embedded into the trajectory of some random variables that may drive a decision, such as the expected cash flows of an investment project or its exit value.3. Finally, this thesis also aims specifically at encouraging the enrichment of real option models. It is striking that only the impact of risk has been widely discussed by the real option theory so far, while the specific impact of ambiguity has been largely ignored. Considering that the real option theory is directly concerned with sources of flexibility, irreversibility and uncertainty in general, ambiguity represents a promising expansion.

This thesis is concerned with the removal of artefacts typical for JPEG im- age compression. First, we describe the mathematical formulation of the JPEG format and the problem of artefact removal. We then formulate the problem as an optimization problem, where the minimized functional is obtained via Bayes' theorem and complex wavelets. We describe proximal operators and algorithms and apply them to the minimization of the given functional. The final algorithm is implemented in MATLAB and tested on several test problems. 1

Microgrids are new challenging power systems under development. This report presents a feasibility study of microgrid development. This is an essential task before implementing microgrid systems. It is extremely important to know the number and size of distributed energy resources (DERs) needed and it is necessary to compare investment costs with benefits in order to evaluate the profitability of microgrids. Under the assumption that a large number of DERs improves the reliability of microgrids an optimization problem is formulated to get the accurate mix of distributed energy resources. Uncertainty in physical and financial parameters is taken into account to model the problem considering different scenarios.  Uncertainty takes place in load demanded, renewable energy generation and electricity market price forecasts, availability of distributed energy resources and the microgrid islanding. It is modeled in a stochastic way. The optimization problem is formulated firstly as a mixed-integer programming solved via branch and bound and then it is improved formulating a two stage problem using Benders’ Decomposition which shortens the problem resolution. This optimization problem is divided in a long-term investment master problem and a short-term operation subproblem and it is solved iteratively until it reaches convergence. Bender’s Decomposition optimization problem is applied to real data from the Illinois Institute of Technology (IIT) and it gives the ideal mix of distributed energy resources for different uncertainty scenarios. These distributed energy resources are selected from an initial set. It proves the usefulness of this optimization technique which can be also applied to different microgrids and data. The different solutions obtained for different scenarios are explained and analyzed. They show the possibility of microgrid implementation and determine the most favorable scenarios to reach the microgrid implementation successfully.  Reliability is a term highly linked to the microgrid concept and one of the most important reasons of microgrid development. Thus an analysis of reliability importance is implemented using the importance index of interruption cost (  ) in order to measure the reliability improvement of developing microgrids. It shows and quantifies the reliability improvement in the system.

This paper presents an approach to operate multi-objective self-optimizing software systems based on the models@run.time paradigm. In contrast to existing approaches, which are usually specific to a single or selected set of objectives (e.g., performance and/or reliability), the presented approach is generic in that it allows the software architect to model the relevant concerns of interest to self-optimization. At runtime, these models are interpreted and used to generate optimization problems. To evaluate the applicability of the approach, a scalability analysis is provided, showing the approach’s feasibility for at least two objectives.

Background: Multiple Objective Optimization problems(MOOPs) are common and evident in every field. Container port terminals are one of the fields in which MOOP occurs. In this research, we have taken a case in logistics management and modelled Multi-agent systems to solve the MOOP using Non-dominated Sorting Genetic Algorithm-II (NSGA-II). Objectives: The purpose of this study is to build AI-based models for solving a Multiple Objective Optimization Problem occurred in port terminals. At first, we develop a port agent with an objective function of maximizing throughput and a customer agent with an objective function of maximizing business profit. Then, we solve the problem using the single-objective optimization model and multi-objective optimization model. We then compare the results of both models to assess their performance. Methods: A literature review is conducted to choose the best algorithm among the existing algorithms, which were used previously in solving other Multiple Objective Optimization problems. An experiment is conducted to know how well the models performed to solve the problem so that all the participants are benefited simultaneously. Results: The results show that all three participants that are port, customer one and customer two have gained profits by solving the problem in multi-objective optimization model. Whereas in a single-objective optimization model, a single participant has achieved earnings at a time, leaving the rest of the participants either in loss or with minimal profits. Conclusion: We can conclude that multi-objective optimization model has performed better than the single-objective optimization model because of the impartial results among the participants.