When creating a muffler to be installed on a noise generating machine, the design parameters as well as the placements of sound attenuating elements has to be optimized in order to minimize the sound coming out of the equipage. This is exemplified in a small project task for students of a basic course in optimization at KTH. The task is however flawed, since both the way in which the optimization problem is formed is overly simplistic and the algorithm used to solve the problem, fmincon, does not cope well with the mathematical complexity of the model, meaning it gets stuck in a local optimum that is not a global optimum. This thesis is about investigating how to solve both of these problems. The model is modified to combine several frequencies and adjusting them to the sensitivity to different frequencies in the human ear. By doing this, the objective is changed from the previous way of maximizing Dynamic Insertion Loss Dilfor a specific frequency to minimize the total perceived sound level LA.  The model is based on the modular design of TMM from four-pole theory. This divides the muffler into separate parts, with the sound attenuating elements being mathematically defined only by what T matrix it has. The element types to choose from are the Expansion Chamber, the Quarter Wave Resonator and the Helmholtz Resonator. The global optimization methods to choose from are Global Search, MultiStart, Genetic Algorithm, Pattern Search and Simulated Annealing. By combining the different types of sound attenuating elements in every way and solving each case with every global optimization method, the best combination to implement to the model is chosen. The choice is two Quarter Wave Resonators being solved by MultiStart, which provides satisfactory results. Further analysis is done to ensure the robustness of chosen implementation, which does not reveal any significant flaws. The purpose of this thesis is fulfilled. / När man skapar en ljuddämpare som ska installeras på en ljud-genererande maskin bör designparametrarna samt placeringarna av ljuddämpande element optimeras för att minimera ljudet som kommer ut ur ekipaget. Detta exemplifieras i en liten projektuppgift för studenter till en grundkurs i optimering på KTH. Uppgiften är dock bristfällig, eftersom både det sätt som optimeringsproblemet är utformat är alltför förenklat och den algoritm som används för att lösa problemet, fmincon, inte klarar av modellens matematiska komplexitet bra, vilket menas med att den fastnar i ett lokalt optimum som inte är ett globalt optimum. Detta examensarbete handlar om att undersöka hur man kan lösa båda dessa problem. Modellen är modifierad för att kombinera flera frekvenser och anpassa dem till känsligheten för olika frekvenser i det mänskliga örat. Genom att göra detta är målet ändrat från det tidigare sättet att maximera den dynamiska insatsisoleringen DIL för en specifik frekvens till att minimera den totala upplevda ljudnivån LA. Modellen bygger på den modulära designen av TMM från 4-polsteori. Detta delar upp ljuddämparen i separata delar, med ljuddämpande element som matematiskt endast definieras av vilken T matris de har. De elementtyper att välja mellan är expansionskammare, kvartsvågsresonator och Helmholtzresonator. De globala optimeringsmetoder att välja mellan är Global Search, MultiStart, Genetic Algorithm, Pattern Search och Simulated Annealing. Genom att kombinera de olika typerna av ljuddämpande element på alla sätt och lösa varje fall med varje global optimeringsmetod, blir den bästa kombinationen vald och implementerad i modellen. Valet är två kvartsvågsresonatorer som löses genom MultiStart, vilket ger tillfredsställande resultat. Ytterligare analyser görs för att säkerställa robustheten av den valda implementationen, som inte avslöjar några väsentliga brister. Syftet med detta examensarbete är uppfyllt.

<p>This thesis concerns the identifiability issue; which, if any, parameters can be deduced from the input and output behavior of a model? The two types of identifiability concepts, a priori and practical, will be addressed and explained. Two methods for identifiability testing are evaluated and the result shows that the two methods work well if they are combined. The first method is for a priori identifiability analysis and it can determine the a priori identifiability of a system in polynomial time. The result from the method is probabilistic with a high probability of correct answer. The other method takes the simulation approach to determine whether the model is practically identifiable. Non-identifiable parameters manifest themselves as a functional relationship between the parameters and the method uses transformations of the parameter estimates to conclude if the parameters are linked. The two methods are verified on models with known identifiability properties and then tested on some examples from systems biology. Although the output from one of the methods is cumbersome to interpret, the results show that the number of parameters that can be determined in practice (practical identifiability) are far fewer than the ones that can be determined in theory (a priori identifiability). The reason for this is the lack of quality, noise and lack of excitation, of the measurements.</p> / <p>Fokus i denna rapport är på identifierbarhetsproblemet. Vilka parametrar kan unikt bestämmas från en modell? Det existerar två typer av identifierbarhetsbegrepp, a priori och praktisk identifierbarhet, som kommer att förklaras. Två metoder för identifierbarhetstestning är utvärderade och resultaten visar på att de två metoderna fungerar bra om de kombineras med varandra. Den första metoden är för a priori identifierbarhetsanalys och den kan avgöra identifierbarheten för ett system i polynomiell tid. Resultaten från metoden är slumpmässigt med hög sannolikhet för ett korrekt svar. Den andra metoden använder sig av simuleringar för att avgöra om modellen är praktiskt identifierbar. Icke-identifierbara parametrar yttrar sig som funktionella kopplingar mellan parametrar och metoden använder sig av transformationer av parameterskattningarna för att avgöra om parametrarna är kopplade. De två metoderna är verifierade på modeller där identifierbarheten är känd och är därefter testade på några exempel från systembiologi. Trots att resultaten från den ena metoden är besvärliga att tolka visar resultaten på att antalet parametrar som går att bestämma i verkligheten (praktiskt identifierbara) är betydligt färre än de parametrar som kan bestämmas i teorin (a priori identifierbara). Anledningen beror på brist på kvalitet, både brus och brist på excitation, i mätningarna.</p>

This thesis concerns the identifiability issue; which, if any, parameters can be deduced from the input and output behavior of a model? The two types of identifiability concepts, a priori and practical, will be addressed and explained. Two methods for identifiability testing are evaluated and the result shows that the two methods work well if they are combined. The first method is for a priori identifiability analysis and it can determine the a priori identifiability of a system in polynomial time. The result from the method is probabilistic with a high probability of correct answer. The other method takes the simulation approach to determine whether the model is practically identifiable. Non-identifiable parameters manifest themselves as a functional relationship between the parameters and the method uses transformations of the parameter estimates to conclude if the parameters are linked. The two methods are verified on models with known identifiability properties and then tested on some examples from systems biology. Although the output from one of the methods is cumbersome to interpret, the results show that the number of parameters that can be determined in practice (practical identifiability) are far fewer than the ones that can be determined in theory (a priori identifiability). The reason for this is the lack of quality, noise and lack of excitation, of the measurements. / Fokus i denna rapport är på identifierbarhetsproblemet. Vilka parametrar kan unikt bestämmas från en modell? Det existerar två typer av identifierbarhetsbegrepp, a priori och praktisk identifierbarhet, som kommer att förklaras. Två metoder för identifierbarhetstestning är utvärderade och resultaten visar på att de två metoderna fungerar bra om de kombineras med varandra. Den första metoden är för a priori identifierbarhetsanalys och den kan avgöra identifierbarheten för ett system i polynomiell tid. Resultaten från metoden är slumpmässigt med hög sannolikhet för ett korrekt svar. Den andra metoden använder sig av simuleringar för att avgöra om modellen är praktiskt identifierbar. Icke-identifierbara parametrar yttrar sig som funktionella kopplingar mellan parametrar och metoden använder sig av transformationer av parameterskattningarna för att avgöra om parametrarna är kopplade. De två metoderna är verifierade på modeller där identifierbarheten är känd och är därefter testade på några exempel från systembiologi. Trots att resultaten från den ena metoden är besvärliga att tolka visar resultaten på att antalet parametrar som går att bestämma i verkligheten (praktiskt identifierbara) är betydligt färre än de parametrar som kan bestämmas i teorin (a priori identifierbara). Anledningen beror på brist på kvalitet, både brus och brist på excitation, i mätningarna.

Submitted by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-02-09T12:44:05Z No. of bitstreams: 2 Dissertação - Romário Pereira Marinho - 2017.pdf: 13877023 bytes, checksum: acc279d7703902ca281c2659e82477a2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Liliane Ferreira (ljuvencia30@gmail.com) on 2018-02-09T12:44:48Z (GMT) No. of bitstreams: 2 Dissertação - Romário Pereira Marinho - 2017.pdf: 13877023 bytes, checksum: acc279d7703902ca281c2659e82477a2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-09T12:44:48Z (GMT). No. of bitstreams: 2 Dissertação - Romário Pereira Marinho - 2017.pdf: 13877023 bytes, checksum: acc279d7703902ca281c2659e82477a2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-25 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The purpose of this work is the solution of the distribution network problem to minimize active power losses using meta-heuristics based on multistart methodology and tabu search. The initialization of both methodologies will be done by solving a power flow for weakly meshed systems whose apparent power will be used by Prim’s algorithm as the weight, which will generate good initial radial topologies. The local searchs implemented are through brach exchanges that aim to improve the solution. The solutions are obtained by programming algorithms implemented in C++ language, which aim to minimize the losses in the distribution feeders. This dissertation is the result of efforts made in the initial stages of the CELG D’s Research and Development (R&D) project, ANEEL’s code PD-6072-0302 / 2015. Therefore, it is one of the project’s by-products entitled: " Sistema de Apoio à Decisão para Restauração de Redes de Distribuição de Energia Elétrica Considerando Curvas de Carga dos Transformadores das Subestações / O objetivo deste trabalho é resolver o Problema de Reconfiguração de Sistemas de Distribuição de Energia Elétrica com foco na minimização das perdas elétricas do sistema através das metodologias metaheurísticas Multipartida e Busca Tabu. A inicialização de ambas metodologias dar-se-á através da resolução de um fluxo de potência para sistemas fracamente malhados cujas potências aparentes resultantes serão utilizadas como pesos ideais no Algoritmo de Prim, o qual gerará topologias iniciais radiais de boa qualidade. As buscas locais adotadas através das trocas ramos visam melhorar a solução inicial obtida. Soluções de reconfiguração de redes elétricas de 14, 33, 84, 136 e 417 nós são obtidas através da programação de algoritmos implementados em linguagem C++, as quais têm como objetivo minimizar as perdas nos alimentadores de distribuição. Esta dissertação é resultado de esforços realizados nas etapas iniciais do projeto de Pesquisa e Desenvolvimento (P&D) da CELG D, código ANEEL PD-6072- 0302/2015. Portanto, constitui-se em um dos subprodutos do projeto intitulado: “Sistema de Apoio à Decisão para Restauração de Redes de Distribuição de Energia Elétrica Considerando Curvas de Carga dos Transformadores das Subestações”.

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-05-22T20:04:01Z No. of bitstreams: 1 TeseALS.pdf: 2588373 bytes, checksum: 85ce391accc868c711a33c83006ee738 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-31T13:43:27Z (GMT) No. of bitstreams: 1 TeseALS.pdf: 2588373 bytes, checksum: 85ce391accc868c711a33c83006ee738 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-31T13:43:34Z (GMT) No. of bitstreams: 1 TeseALS.pdf: 2588373 bytes, checksum: 85ce391accc868c711a33c83006ee738 (MD5) / Made available in DSpace on 2017-05-31T13:52:08Z (GMT). No. of bitstreams: 1 TeseALS.pdf: 2588373 bytes, checksum: 85ce391accc868c711a33c83006ee738 (MD5) Previous issue date: 2017-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Vehicle routing problems occur in many practical situations where the distribution of goods and / or services to different demand points is necessary. In this context, this research aims to study a ship routing and scheduling problem that arises at the collection and delivery operations of different types of crude oil from offshore platforms to coastal terminals. In the paradigm adopted for the representation of the problem, the transportation is largely the result of the need to maintain inventories at each supply point (platforms) between minimum and maximum levels, considering production rates on these operating points and the demand attendance of each product in the coastal terminals. The routing and scheduling of the fleet aims to achieve minimum variable cost solutions, and considers various operational constraints, such as the maximum cargo volume transported on each ship, the ships mooring in the operational points ports, the simultaneous unloading of the ships in terminals with more than one berth, among many others. In this research, Inventory Constrained Routing Problem (ICRP) models in the maritime context have been modified and extended for appropriately representating and solving real problems based on data collected in a case study performed on a Brazilian oil company, involving relatively short distances and time horizons. Small sized instances are solved by a mathematical programming software. Given the difficulties of solving larger examples, this study proposes a multistart heuristic method that includes a metaheuristic GRASP and improvement procedures, and also a rolling horizon heuristic. Both methods provide feasible good quality solutions in reasonable computing times. In order to improve the quality of the solutions found by these constructive methods, it is also discussed a procedure that combines the mathematical programming software and local search heuristic methods (matheuristic). The results show the potential of the proposed models and solution methods to tackle the problem and produce competitive solutions. / Problemas de roteirização de veículos ocorrem em diversas situações práticas onde se faz necessária a distribuição de bens e/ou serviços a pontos dispersos de demanda. Nesse contexto, a presente pesquisa visa o estudo de um problema de roteirização e programação de navios presente em operações de coleta e entrega de diferentes tipos de óleo cru de diversas plataformas offshore para vários terminais costeiros. No paradigma adotado para representação do problema, o transporte dos produtos é em grande parte o resultado da necessidade de manutenção dos estoques em cada ponto de suprimento (plataformas) entre níveis mínimos e máximos, considerando-se as taxas de produção nesses pontos operacionais, assim como o atendimento da demanda de cada produto nos terminais costeiros para abastecer as refinarias. A roteirização e programação da frota visa a obtenção de soluções de mínimo custo variável e considera várias restrições operacionais, tais como o volume máximo de carga transportada em cada navio, a viabilidade de atracação de navios em portos dos pontos operacionais, os descarregamentos simultâneos de navios em terminais com mais de um berço, dentre várias outras. Nesse sentido, modelos de otimização da literatura de roteirização veículos com restrições de estoque (Inventory Constrained Routing Problem – ICRP) no contexto marítimo foram modificados e estendidos para representação do problema e resolução de exemplares de uma situação real, definidos a partir de dados coletados em um estudo de caso realizado em uma empresa petrolífera nacional, envolvendo distâncias relativamente curtas e com horizontes de planejamento de curto prazo (poucas semanas). Exemplares de pequeno porte são resolvidos por meio da utilização de um software de programação matemática. Dada a dificuldade de resolução dos exemplos de maior porte, é proposto um método heurístico de múltiplos reinícios composto por uma metaheurística GRASP e procedimentos de melhoria, além de uma heurística de horizonte rolante, que proporcionaram a obtenção de soluções factíveis de boa qualidade em tempos computacionais aceitáveis. Com intuito de melhorar a qualidade das soluções encontradas pelos métodos construtivos, é também discutido um procedimento que combina o software de programação matemática e métodos heurísticos com busca local (mateheurística). Os resultados mostram o potencial dos modelos e métodos de solução aqui desenvolvidos e propostos para abordar o problema e produzir soluções competitivas em relação às soluções da empresa.