Na presente tese é resolvida a equação de difusão de nêutrons estacionária, bem como problemas de cinética, em geometria unidimensional cartesiana multi-região considerando o modelo de multigrupos de energia. Um dos objetivos e inovação neste trabalho é a obtenção de uma solução aproximada com estimativa de erro, controle de precisão e na forma de uma expressão analítica. Com esse tipo de solução não há a necessidade de recorrer a esquemas de interpolação, geralmente necessários em caso de discretizações do domínio. O fluxo de nêutrons é expandido em uma série de Taylor cujos coeficientes são encontrados utilizando a equação diferencial e as condições de contorno e interface. O domínio é dividido em várias células, cujo tamanho e o grau do polinômio são ajustáveis de acordo com a precisão requerida. Para resolver o problema de autovalor é utilizado o método da potência. A metodologia é aplicada em um benchmark que consiste na solução da equação de difusão como condição inicial e na solução de problemas de cinética para diferentes transientes. Os resultados são comparados com sucesso com resultados da literatura. A convergência da série é garantida pela aplicação de um raciocínio baseado no critério de Lipschitz para funções contínuas. Cabe ressaltar que a solução obtida, em conjunto com a análise da convergência, mostra a solidez e a precisão dessa metodologia. / In the present dissertation the one-dimensional neutron diffusion equation for stationary and kinetic problems in a multi-layer slab has been solved considering the multi-group energy model. One of the objectives and innovation in this work is to obtain an approximate solution with error estimation, accuracy control and in the form of an analytical expression. With this solution there is no need for interpolation schemes, which are usually needed in case of discretization of the domain. The neutron flux is expanded in a Taylor series whose coefficients are found using the differential equation and the boundary and interface conditions. The domain is divided into several layers, whose size and the polynomial order can be adjusted according to the required accuracy. To solve the eigenvalue problem the conventional power method has been used. The methodology is applied in a benchmark problem consisting of the solution of the diffusion equation as an initial condition and solving kinetic problems for different transients. The results are compared successfully with the ones in the literature. The convergence of the series is guaranteed by applying a criterion based on the Lipschitz criterion for continuous functions. Note that the solution obtained, together with the convergence analysis, shows the robustness and accuracy of this methodology.

L’accroissement des profits, à travers l’amélioration de la productivité et la réduction des pertes de matières, représente un objectif primordial pour les entreprises industrielles. Dans cette thèse, nous nous intéressons à la résolution d’un problème industriel complexe réel avec des contraintes de temps. Nous nous sommes intéressés, tout d’abord, à un objectif principal, soit la minimisation des dates de fin de production, suivi d’un objectif secondaire qui est la minimisation des quantités de déchets non recyclables. Dans un premier temps, nous avons modéliséle problème par des modèles mathématiques, que nous avons résolu à l’aide d’un solveur. Dans un second temps, nous avons proposé une méthode approchée en forme d’algorithmes évolutionnistes. Cette méthode est appliquée aux deux objectifs mentionnés ci-dessus séparément. Une troisième méthode est ensuite appliquée à l’objectif principal, à savoir une méthode arborescente approchée. Nous avons testé les algorithmes proposés sur des instances inspirées d’un cas réel ; issues d’une entreprise du secteur agroalimentaire et sur des instances inspirées de la littérature. / Increasing profits, through the improvement of productivity and minimizing waste, is a primary objective for industrial companies. In this thesis, we are interested insolving a real complex industrial problem with time constraints. Firstly, we were interested in minimizing completion time (Cmax). Secondly, we focused on minimizing of non-recyclable waste. As a first step, we formulated the problem by mathematical models, which we solved using a solver. In a second step, we proposed an approximate method in the form of evolutionary algorithms. Both methods were applied to the two objectives mentioned above separately. Then, a third method which is a tree-search algorithm was applied only to the main objective. We tested the proposed algorithms on instances inspired from a real case; from an agri-food business, and also on instances inspired from the literature.

Na presente tese é resolvida a equação de difusão de nêutrons estacionária, bem como problemas de cinética, em geometria unidimensional cartesiana multi-região considerando o modelo de multigrupos de energia. Um dos objetivos e inovação neste trabalho é a obtenção de uma solução aproximada com estimativa de erro, controle de precisão e na forma de uma expressão analítica. Com esse tipo de solução não há a necessidade de recorrer a esquemas de interpolação, geralmente necessários em caso de discretizações do domínio. O fluxo de nêutrons é expandido em uma série de Taylor cujos coeficientes são encontrados utilizando a equação diferencial e as condições de contorno e interface. O domínio é dividido em várias células, cujo tamanho e o grau do polinômio são ajustáveis de acordo com a precisão requerida. Para resolver o problema de autovalor é utilizado o método da potência. A metodologia é aplicada em um benchmark que consiste na solução da equação de difusão como condição inicial e na solução de problemas de cinética para diferentes transientes. Os resultados são comparados com sucesso com resultados da literatura. A convergência da série é garantida pela aplicação de um raciocínio baseado no critério de Lipschitz para funções contínuas. Cabe ressaltar que a solução obtida, em conjunto com a análise da convergência, mostra a solidez e a precisão dessa metodologia. / In the present dissertation the one-dimensional neutron diffusion equation for stationary and kinetic problems in a multi-layer slab has been solved considering the multi-group energy model. One of the objectives and innovation in this work is to obtain an approximate solution with error estimation, accuracy control and in the form of an analytical expression. With this solution there is no need for interpolation schemes, which are usually needed in case of discretization of the domain. The neutron flux is expanded in a Taylor series whose coefficients are found using the differential equation and the boundary and interface conditions. The domain is divided into several layers, whose size and the polynomial order can be adjusted according to the required accuracy. To solve the eigenvalue problem the conventional power method has been used. The methodology is applied in a benchmark problem consisting of the solution of the diffusion equation as an initial condition and solving kinetic problems for different transients. The results are compared successfully with the ones in the literature. The convergence of the series is guaranteed by applying a criterion based on the Lipschitz criterion for continuous functions. Note that the solution obtained, together with the convergence analysis, shows the robustness and accuracy of this methodology.

Context: The importance of testing non-functional properties of the system is growing steadily. Complexity factor of the software is growing proportionally with the growing demands and hence attributes like performance, energy consumption and reliability are proving to be very crucial. Optimizing the software with respect to these properties simultaneously with the functional properties has been found to be a challenge. Search-based Software testing automates this process by using different meta-heuristic techniques. It assures the generation of large number of test cases at a minimal cost. Carrying out testing in this context requires lot of expertise and the aid of a highly flexible approach. There is a strong need of a guide that helps the practitioners(testers) and researchers optimize the non-functional properties using Search-based software testing. Objectives: The objective of the work presented in this thesis is to, first, investigate the non-functional properties, challenges encountered and approaches/suggestions by the practitioners on the application of Search-based software testing in academia and industry. Second objective is to map all the information into a conceptual/ theoretical framework that could be used by Search-based software testing practitioners for optimizing the non-functional system properties. Methods: A qualitative approach has been employed for this thesis work. A literature review with snowball sampling as the search approach was conducted to collect the information regarding the different kinds of systems being tested, the non-functional system properties being optimized, challenges encountered and the tools used for this purpose. Semi-structured interviews are conducted as a part of the validation process and generalizing the results obtained. A total of 9 interviews were conducted. Thematic analysis technique has been used to analyze the collected data. Results: As a result of conducting this research, different dimensions forming the framework have been investigated. The overall result of this study is the formulation fo a framework and that has been validated by conducting interviews. The framework consists of 16 challenges related to the field of Non-functional Search-based software testing. Conclusions: It is found out that Search-based testing for non-functional properties has not been extensively applied in the industry. It has been suggested, used and applied in academia for the most part. Several factors influence the selection of non-functional properties for optimization. Most of the challenges being faced in this subject are inclined towards three areas in Search-based testing. Performance, execution time and energy consumption are three most popularly tested attributes. Further research could be done wherein the framework generated could be put to use by different practitioners and researchers to find out interesting things.

Na presente tese é resolvida a equação de difusão de nêutrons estacionária, bem como problemas de cinética, em geometria unidimensional cartesiana multi-região considerando o modelo de multigrupos de energia. Um dos objetivos e inovação neste trabalho é a obtenção de uma solução aproximada com estimativa de erro, controle de precisão e na forma de uma expressão analítica. Com esse tipo de solução não há a necessidade de recorrer a esquemas de interpolação, geralmente necessários em caso de discretizações do domínio. O fluxo de nêutrons é expandido em uma série de Taylor cujos coeficientes são encontrados utilizando a equação diferencial e as condições de contorno e interface. O domínio é dividido em várias células, cujo tamanho e o grau do polinômio são ajustáveis de acordo com a precisão requerida. Para resolver o problema de autovalor é utilizado o método da potência. A metodologia é aplicada em um benchmark que consiste na solução da equação de difusão como condição inicial e na solução de problemas de cinética para diferentes transientes. Os resultados são comparados com sucesso com resultados da literatura. A convergência da série é garantida pela aplicação de um raciocínio baseado no critério de Lipschitz para funções contínuas. Cabe ressaltar que a solução obtida, em conjunto com a análise da convergência, mostra a solidez e a precisão dessa metodologia. / In the present dissertation the one-dimensional neutron diffusion equation for stationary and kinetic problems in a multi-layer slab has been solved considering the multi-group energy model. One of the objectives and innovation in this work is to obtain an approximate solution with error estimation, accuracy control and in the form of an analytical expression. With this solution there is no need for interpolation schemes, which are usually needed in case of discretization of the domain. The neutron flux is expanded in a Taylor series whose coefficients are found using the differential equation and the boundary and interface conditions. The domain is divided into several layers, whose size and the polynomial order can be adjusted according to the required accuracy. To solve the eigenvalue problem the conventional power method has been used. The methodology is applied in a benchmark problem consisting of the solution of the diffusion equation as an initial condition and solving kinetic problems for different transients. The results are compared successfully with the ones in the literature. The convergence of the series is guaranteed by applying a criterion based on the Lipschitz criterion for continuous functions. Note that the solution obtained, together with the convergence analysis, shows the robustness and accuracy of this methodology.

Résumé : Depuis la fin du XXème siècle, l’augmentation du prix du pétrole brut et les problématiques environnementales poussent l’industrie automobile à développer des technologies plus économes en carburant et générant moins d’émissions de gaz à effet de serre. Parmi ces technologies, les véhicules électriques hybrides constituent une solution viable et performante. En alliant un moteur électrique et un moteur à combustion, ces véhicules possèdent un fort potentiel de réduction de la consommation de carburant sans sacrifier son autonomie. La présence de deux moteurs et de deux sources d’énergie requiert un contrôleur, appelé système de gestion d’énergie, responsable de la commande simultanée des deux moteurs. Les performances du véhicule en matière de consommation dépendent en partie de la conception de ce contrôleur. Les véhicules électriques hybrides rechargeables, plus récents que leur équivalent non rechargeable, se distinguent par l’ajout d’un chargeur interne permettant la recharge de la batterie pendant l’arrêt du véhicule et par conséquent la décharge de celle-ci au cours d’un trajet. Cette particularité ajoute un degré de complexité pour ce qui est de la conception du système de gestion d’énergie. Dans cette thèse, nous proposons un modèle complet du véhicule dédié à la conception du contrôleur. Nous étudions ensuite la dépendance de la commande optimale des deux moteurs par rapport au profil de vitesse suivi au cours d’un trajet ainsi qu’à la quantité d’énergie électrique disponible au début d’un trajet. Cela nous amène à proposer une technique d’auto-apprentissage visant l’amélioration de la stratégie de gestion d’énergie en exploitant un certain nombre de données enregistrées sur les trajets antérieurs. La technique proposée permet l’adaptation de la stratégie de contrôle vis-à-vis du trajet en cours en se basant sur une pseudo-prédiction de la totalité du profil de vitesse. Nous évaluerons les performances de la technique proposée en matière de consommation de carburant en la comparant avec une stratégie optimale bénéficiant de la connaissance exacte du profil de vitesse ainsi qu’avec une stratégie de base utilisée couramment dans l’industrie. // Abstract : Since the end of the XXth century, the increase in crude oil price and the environmental concerns lead the automotive industry to develop technologies that can improve fuel savings and decrease greenhouse gases emissions. Among these technologies, the hybrid electric vehicles stand as a reliable and efficient solution. By combining an electrical motor and an internal combustion engine, these vehicles can bring a noticeable improvement in terms of fuel consumption without sacrificing the vehicle autonomy. The two motors and the two energy storage systems require a control unit, called energy management system, which is responsible for the command decision of both motors. The vehicle performances in terms of fuel consumption greatly depend on this control unit. The plug-in hybrid electric vehicles are a more recent technology compared to their non plug-in counterparts. They have an extra internal battery charger that allows the battery to be charged during OFF state, implying a possible discharge during a trip. This particularity adds complexity when it comes to the design of the energy management system. In this thesis, a complete vehicle model is proposed and used for the design of the controller. A study is then carried out to show the dependence between the optimal control of the motors and the speed profile followed during a trip as well as the available electrical energy at the beginning of a trip. According to this study, a self-learning optimization technique that aims at improving the energy management strategy by exploiting some driving data recorded on previous trips is proposed. The technique allows the adaptation of the control strategy to the current trip based on a pseudo-prediction of the total speed profile. Fuel consumption performances for the proposed technique will be evaluated by comparing it with an optimal control strategy that benefits from the exact a priori knowledge of the speed profile as well as a basic strategy commonly used in industry.

<p>In this Phd thesis, heuristic, meta-heuristic and predictive methods are<br />considered. Meta-heuristics optimisation of the transverse load distribution<br />factor of helical and spur gears is conducted. The multi-objective optimisation<br />problem of the planetary gear train is done using Genetic Algorithm method.<br />A comparative study of several meta-heuristic methods is given for solving<br />the problem of dynamic load capacity and working life at radial ball bearings.<br />Bayesian network, as a predictive method, is implemented in the software to<br />support the decision making in complex mechanical plants.</p> / <p>Докторска дисертација се бави темама везаним за хеуристичке,<br />метахеуристичке и предикционе методе. Извршена је метахеуристичка<br />оптимизација проблема трансверзалног фактора расподеле<br />оптерећења код цилиндричног зупчастог пара. Вишекритеријумски<br />проблем геометрије планетарног преносника је решаван применом<br />генетских алгоритама. Поређење неколико метахеуристичких метода је<br />дато на решавању оптимизационог проблема радног века и динамичке<br />носивости код котрљајних кугличних лежаја. Бајесове мреже, као<br />предикциона метода, су уграђене у софтвер за подршку одлучивању у<br />комплексним машинским постројењима.</p> / <p>Doktorska disertacija se bavi temama vezanim za heurističke,<br />metaheurističke i predikcione metode. Izvršena je metaheuristička<br />optimizacija problema transverzalnog faktora raspodele<br />opterećenja kod cilindričnog zupčastog para. Višekriterijumski<br />problem geometrije planetarnog prenosnika je rešavan primenom<br />genetskih algoritama. Poređenje nekoliko metaheurističkih metoda je<br />dato na rešavanju optimizacionog problema radnog veka i dinamičke<br />nosivosti kod kotrljajnih kugličnih ležaja. Bajesove mreže, kao<br />predikciona metoda, su ugrađene u softver za podršku odlučivanju u<br />kompleksnim mašinskim postrojenjima.</p>

O presente trabalho otimizou os parâmetros concentrados do sistema de suspensão de um modelo de veículo completo, representando um automóvel de passeio que trafega a uma velocidade constante por um determinado perfil de pista previsto na norma ISO 8608, 1995, através da utilização de um algoritmo meta-heurístico de otimização multiobjetivo. Duas rotinas numérico-computacionais foram desenvolvidas, visando realizar tal otimização tanto no domínio do tempo quanto no domínio da frequência. A utilização de algoritmos meta-heurísticos vem ganhando espaço na otimização de sistemas mecânicos, proporcionando rapidez e precisão na obtenção de resultados ótimos. Ao se combinar um algoritmo de otimização a um modelo que represente satisfatoriamente um sistema mecânico, obtém-se uma ferramenta indicadora dos parâmetros de máxima eficiência do sistema, que pode ser utilizada em inúmeras aplicações. Pretendeu-se, com a integração de rotinas de análise dinâmica nos domínios do tempo e da frequência ao algoritmo genético de otimização multiobjetivo NSGA-II, desenvolvido por Deb et al., 2002, a obtenção de duas fronteiras ótimas de Pareto. Estas fronteiras consistem no conjunto de soluções não dominadas que minimizam as seguintes funções objetivo: o valor RMS ponderado da aceleração vertical do assento do motorista, o valor RMS da média do fator de amplificação dinâmica das quatro rodas do modelo e o máximo deslocamento relativo entre cada roda e a carroceria. O método proposto por Shinozuka e Jan, 1972, é utilizado para a obtenção do perfil de irregularidades da pista no domínio do tempo a partir das equações de densidade espectral de potência (PSD) que representam as diferentes classes de pavimentos. O método de Newmark, 1959, é utilizado para resolver a equação diferencial de movimento no domínio do tempo e obter a resposta dinâmica do modelo a tais irregularidades. O comportamento dinâmico do modelo de veículo no domínio da frequência foi obtido através da utilização da função de resposta em frequência (FRF) do modelo de veículo analisado. Os resultados demonstraram a capacidade de ambas as rotinas de análise dinâmica desenvolvidas de produzir resultados consistentes com os encontrados na literatura, bem como a capacidade dos algoritmos de otimização implementados de fornecer fronteiras ótimas de Pareto para os problemas propostos. / The proposed work optimized the concentrated parameters of a full-vehicle model’s suspension system, being that model representative of a passenger car which travels at a constant speed on a certain road profile provided by the ISO 8608, 1995, standard, using a multi-objective meta-heuristic optimization algorithm. Two numerical-computational routines were developed, seeking to perform said optimization for both the time and frequency domains. The use of meta-heuristic algorithms has been increasing in mechanical systems optimization, providing speed and accuracy in obtaining an optimal result. Combining an optimization algorithm with a model that satisfactorily represents a mechanical system yields a tool that indicates the system’s maximum efficiency parameters, which can be used in numerous applications. It was intended, with the integration of the dynamic analysis routines to the multi-objective genetic optimization algorithm NSGA-II, developed by Deb et al., 2002, the obtainment of two Pareto-optimal fronts. These fronts consist in the set of non-dominated solutions that minimize the following objective functions: the weighted RMS value of the driver’s seat vertical acceleration, the mean RMS value of the model wheel’s dynamic amplification factor, and the maximum relative displacement between each wheel and the body of the vehicle model. The method proposed by Shinozuka and Jan, 1972, is used to obtain the road irregularity profile in the time domain from the power spectral density (PSD) equations that represent the different pavement classes. The Newmark’s method (1959) is used to solve the differential motion equation in the time domain, in order to obtain the vehicle model’s responses to these irregularities. The dynamic behavior of the vehicle model in the frequency domain was obtained through the use of the frequency response function (FRF) of the analyzed model. The results showed the capacity of both the dynamic analysis routines developed in generating results that are consistent with those found in literature, as well as the capacity of the optimization algorithms implemented in providing Pareto optimal fronts to the proposed problems.

Orientador: Rubén Augusto Romero Lázaro / Resumo: O principal objetivo deste trabalho é a implementação de uma metodologia que, utilizando a meta-heurística de busca dispersa (BD) resolva o problema de fluxo de potência ótimo (FPO) considerando o desligamento de linhas de transmissão (OTS) para a redução dos custos de ope-ração. Com o objetivo de avaliar o potencial da meta-heurística, o algoritmo de BD foi imple-mentado para otimizar funções multimodais restritas, metodologia denominada BD-FMR, e para resolver o problema de FPO, metodologia denominada BD-FPO. Foram realizados testes com onze problemas de funções multimodais restritas disponíveis na literatura especializada, utili-zando a metodologia BD-FMR, sendo que os resultados obtidos são comparáveis com os me-lhores resultados disponíveis na literatura. O problema de FPO foi resolvido pela metodologia BD-FPO utilizando três sistemas teste de 6, 14 e 57 barras, sendo que os resultados não foram satisfatórios quando comparados com as soluções do modelo exato do problema obtidas pelo solver KNITRO. Entretanto, o algoritmo BD-FPO serviu de base para a implementação da me-todologia principal deste trabalho. Por fim, a metodologia BD-OTS foi implementada em lin-guagem de programação C/C++, com a utilização de recursos de programação paralela através da biblioteca OpenMP. Neste trabalho a formulação utilizada para representar a operação da rede considera o modelo AC (corrente alternada), que consiste em um problema de programa-ção não linear inteira mista (PNLIM) devido a pre... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The main objective of this work is the implementation of a methodology that, using the scatter search meta-heuristic (SS) solves the problem of optimal power flow (OPF) considering trans-mission switching (TS) to reduce the operation costs. In order to evaluate the potential of the meta-heuristic, the SS algorithm was implemented to optimize constrained multimodal func-tions, a methodology called BD-FMR, and to solve the OPF problem, a methodology called BD-FPO. Eleven constrained multimodal problems available in the specialized literature were solved using the BD-FMR method, and the results obtained are comparable with the best results available in the literature. The OPF problem was solved by the BD-FPO methodology using three test systems with 6, 14, and 57 buses, and the results were not satisfactory when compared to the solutions of the exact formulation of the problem obtained by the KNITRO solver. How-ever, the BD-FPO algorithm served as the basis for the implementation of the main method of this work. Finally, the BD-OTS method was implemented in the C/C ++ programming lan-guage, using parallel programming resources through the OpenMP library. In this work, the formulation used to represent the operation of the grid considers the alternating current (AC) model, which consists of a mixed-integer nonlinear programming (MINLP) problem due to the presence of discrete variables related to the operation state a line, transformer tap position and the operating state of the s... (Complete abstract click electronic access below) / Doutor

In this thesis, meta-heuristic algorithms are developed to obtain optimum or near optimum solutions for the time-cost-resource trade-off and resource leveling problems in project scheduling. Time cost trade-off, resource leveling, single-mode resource constrained project scheduling, multi-mode resource constrained project scheduling and resource constrained time cost trade-off problems are analyzed. Genetic algorithm simulated annealing, quantum simulated annealing, memetic algorithm, variable neighborhood search, particle swarm optimization, ant colony optimization and electromagnetic scatter search meta-heuristic algorithms are implemented for time cost trade-off problems with unlimited resources. In this thesis, three new meta-heuristic algorithms are developed by embedding meta-heuristic algorithms in each other. Hybrid genetic algorithm with simulated annealing presents the best results for time cost trade-off. Resource leveling problem is analyzed by five genetic algorithm based meta-heuristic algorithms. Apart from simple genetic algorithm, four meta-heuristic algorithms obtained same schedules obtained in the literature. In addition to this, in one of the test problems the solution is improved by the four meta-heuristic algorithms. For the resource constrained scheduling problems / genetic algorithm, genetic algorithm with simulated annealing, hybrid genetic algorithm with simulated annealing and particle swarm optimization meta-heuristic algorithms are implemented. The algorithms are tested by using the project sets of Kolisch and Sprecher (1996). Genetic algorithm with simulated annealing and hybrid genetic algorithm simulated annealing algorithm obtained very successful results when compared with the previous state of the art algorithms. 120-activity multi-mode problem set is produced by using the single mode problem set of Kolisch and Sprecher (1996) for the analysis of resource constrained time cost trade-off problem. Genetic algorithm with simulated annealing presented the least total project cost.