Submitted by Maurílio Figueiredo (maurilioafigueiredo@yahoo.com.br) on 2014-06-30T19:54:20Z No. of bitstreams: 2 license_rdf: 22190 bytes, checksum: 19e8a2b57ef43c09f4d7071d2153c97d (MD5) DISSERTAÇÃO_MetaheurísticasBuscaLocal.pdf: 5158364 bytes, checksum: 9ff1b731ffa05dadf988172a590814c1 (MD5) / Approved for entry into archive by Gracilene Carvalho (gracilene@sisbin.ufop.br) on 2014-07-07T13:15:13Z (GMT) No. of bitstreams: 2 license_rdf: 22190 bytes, checksum: 19e8a2b57ef43c09f4d7071d2153c97d (MD5) DISSERTAÇÃO_MetaheurísticasBuscaLocal.pdf: 5158364 bytes, checksum: 9ff1b731ffa05dadf988172a590814c1 (MD5) / Made available in DSpace on 2014-07-07T13:15:13Z (GMT). No. of bitstreams: 2 license_rdf: 22190 bytes, checksum: 19e8a2b57ef43c09f4d7071d2153c97d (MD5) DISSERTAÇÃO_MetaheurísticasBuscaLocal.pdf: 5158364 bytes, checksum: 9ff1b731ffa05dadf988172a590814c1 (MD5) Previous issue date: 2014 / Este trabalho apresenta uma proposta e a avaliação computacional de quatro métodos de busca local estocástica para o problema de sequenciamento de tarefas em máquinas paralelas não relacionadas com tempo de preparação dependente da sequência (UPMSP - unrelated parallel machine scheduling problem with sequence dependent setup times). As quatro abordagens metaheurísticas que são analisadas para o UPMSP baseam-se em: Simulated Annealing (SA), Iterated Local Search (ILS), Late Acceptance Hill Climbing (LAHC) e Step Counting Hill Climbing (SCHC). A estrutura das vizinhancas, bem como os parâmetros dos algoritmos, foram amplamente testados e analisados, sendo possível verificar como os parâmetros afetam o comportamento de cada algoritmo implementado e pesquisar os melhores parâmetros. As comparações dos resultados obtidos foram realizadas com os resultados apresentados por Vallada e Ruiz (2011), proponentes do conjunto de 50 instâncias consideradas e, mais recentemente, por Haddad (2012). O método que obteve o melhor resultado nessas 50 instâncias foi testado para todas as 1.000 instâncias grandes, apresentadas por Vallada e Ruiz (2011), melhorando em 96,6% (966 instâncias) a melhor solução conhecida encontrada por esses últimos autores. __________________________________________________________________________________________ / ABSTRACT: This paper presents a proposal and a computational review of four methods of stochastic local search to the unrelated parallel machine scheduling problem with sequence dependent setup times (UPMSP). The four metaheuristics approaches that are analyzed for the UPMSP are based in: Simulated Annealing (SA), Iterated Local Search (ILS), Late Acceptance Hill Climbing (LAHC) and Step Counting Hill Climbing (SCHC). The structure of neighborhoods, as well as the parameters of the algorithms, were widely tested and analyzed, being possible verify how the parameters affect the behavior of each algorithm implemented and search the best parameters. The comparisons of the results were accomplished with the results presented by Vallada and Ruiz (2011), who proposed the set of 50 instances considered, and, more recently, by Haddad (2012). The method that got the best result in these 50 instances was tested for every 1.000 large instances, presented by Vallada and Ruiz (2011), improving in 96.6% (966 instances) the best known solution found by this last authors

Esse trabalho tem dois objetivos principais: o primeiro deles consiste em apresentar o estado da arte sobre processos de otimização combinatorial dando uma ênfase especial ao método Simulated Annealing (SA). São apresentados seu histórico, funcionalidades, algoritmo genérico e propostas de paralelização presentes na literatura. Além disso, é apresentado o algoritmo de geração de redes aleatórias contínuas, algoritmo, esse, projetado por pesquisadores do Instituto de Física da UFRGS que utiliza o método SA para gerar redes que atendam certas restrições. O segundo objetivo consiste empropor a paralelização desse algoritmo visando diminuir significativamente o tempo de geração de cada rede, que com o algoritmo seqüencial chega a demorar mais de um mês. Nessa etapa foi utilizada uma adaptação de um dos métodos propostos pela literatura juntamente com a técnica de divisão de domínio. Os resultados obtidos mostraram-se satisfatórios tanto em relação à qualidade numérica quanto à diminuição do tempo de processamento. Além disso, discute-se no trabalho a genericidade da proposta de paralelização a outros problemas baseados em SA. / This work has two main goals: the first one is to present the state of the art on combinatorial optimization processes, with a special emphasis to the Simulated Annealing (SA) method. The work presents its history, features, generic algorithm and proposed parallelization present in the literature. Moreover, the algorithm to generate random networks continued is presented. This algorithm was designed by researchers of the UFRGS Physics Institute and it uses the SA method. The second goal of this work is to propose a parallelization for this algorithm in order to decrease significantly the generation time of each network, that with the sequential algorithm reaches more than months. To do that was used an adaptation of one of the methods proposed by literature together with the domain partitioning technical. The results were satisfactory in terms of the numerical quality and in the decrease of the processing time. In addition, this work discusses the genericity of the proposed parallelization to other problems based on SA.

Submitted by Felipe Alves Pires null (fealvespires@hotmail.com) on 2017-05-15T17:24:32Z No. of bitstreams: 1 Dissertação_Felipe_final.pdf: 9171100 bytes, checksum: b1b4cdbe6480b62edce35f61d888f5b9 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-16T14:44:07Z (GMT) No. of bitstreams: 1 pires_fa_me_bauru.pdf: 9171100 bytes, checksum: b1b4cdbe6480b62edce35f61d888f5b9 (MD5) / Made available in DSpace on 2017-05-16T14:44:07Z (GMT). No. of bitstreams: 1 pires_fa_me_bauru.pdf: 9171100 bytes, checksum: b1b4cdbe6480b62edce35f61d888f5b9 (MD5) Previous issue date: 2017-03-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Devido à crescente demanda por sistemas de comunicação, monitoramento territorial e previsão climática, satélites foram lançados por agências espaciais e aproximadamente 2,271 orbitam a Terra. Com o objetivo de minimizar os custos de lançamento, estruturas espaciais devem possuir forma de sistemas do tipo treliça devido à considerável redução de peso por serem montadas em uma forma triangular e com materiais leves, por exemplo, alumínio. Como resultado, alguns problemas como flexibilidade e baixo amortecimento estrutural podem aparecer. Diante disso, um método de controle deve ser aplicado para manter os níveis de vibração em pequenas escalas. Neste trabalho, um método de controle passivo é aplicado a uma treliça espacial utilizando o método dos elementos finitos (MEF). MEF é uma das ferramentas computacionais mais utilizadas para analisar estruturas sujeitas a vibrações, tornando possível prever as respostas em frequência (FRFs) do sistema. Este trabalho utiliza a técnica de otimização \textit{simulated annealing} para otimizar a norma $\mathcal{H}_{2}$ para os seis primeiros modos de vibrar do sistema de maneira a encontrar as coordenadas de cada nó da treliça que minimizem o valor de norma $\mathcal{H}_{2}$. Nota-se que, com a minimização da norma $\mathcal{H}_{2}$, novas coordenadas das juntas podem ser obtidas e novas FRFs podem ser estudadas. Algumas amplitudes de vibração das FRFs diminuíram, porém algumas amplitudes aumentaram. Verifica-se que houve regiões que o controle aplicado foi efetivo e outras que a técnica não mostrou eficiência. O método estatístico simulação de Monte Carlo também é aplicado para estudar as incertezas associadas ao sistema. Para isto, histogramas são utilizados para verificação das distribuições das frequências naturais. É pertinente a necessidade de avaliar se as distribuições de frequências apresentam um comportamento de curvas normais e para isso alguns parâmetros estatísticos, como \textit{skewness}, \textit{kurtosis} e teste de qui-quadrado, são utilizados. Observa-se que, as incertezas relacionadas à geometria da estrutura afetam mais o sistema do que as incertezas ligadas às propriedades do material. / Due to the increasing demand for monitoring for telecommunication systems, weather and territorial monitoring, satellites have been launched by space agencies and 2,271 still orbit Earth. In order to minimize rocket launch costs, space structures should have the shape of trusses because of the significant weight reduction for being assembled in a triangular form and with elements made of light materials (e.g. aluminum). As a result of it, some problems such as flexibility and low structural damping may arise. For this reason, a control method must be applied to maintain the requirements of vibration levels in these types of structures. This work applies a passive vibration control to a space truss utilizing the Finite Element Method (FEM). FEM is one of the most used computational tools to analyze structures under vibrations and is also used to predict the system’s frequency response functions (FRFs). This work utilizes the optimization technique simulated annealing in order to optimize the norm H2 of the first six vibration modes of the system so that it’s possible to find the coordinates of each node of the space truss that minimize the value of H2. It has been noticed that with the minimization of the H2 norm, new coordinates of the joints can be obtained so that new FRFs can be studied. Some amplitudes of vibration in the FRFs diminished, however, some of them rose. It is verified that there are regions where the control method applied was effective and others where the control technique was not effective. The statistical method Monte Carlo simulation is also applied to study the uncertainties associated to the system. For this study, histograms are utilized to verify the natural frequencies distributions. It is pertinent the need to evaluate whether the frequencies distributions present the behavior of normal curves and to do this, some statistical parameters such as skewness, kurtosis and chi-square test are used. It has been noticed that uncertainties related to the geometry of the structure affect the system more than uncertainties related to the material properties.

Orientador: Peter Christian Hackspacher / Coorientador: Eduardo Augusto Campos Curvo / Banca: Julio Cesar Hadler Neto / Banca: Sandro Guedes de Oliveira / Resumo: No presente trabalho foram efetuados estudos sobre o annealing dos traços de fissão em epídoto. Os experimentos foram feitos aquecendo-se o mineral por tempos de 1, 10 e 100 horas, variando a temperatura de 350 a 950°C. Os resultados obtidos foram curvas de annealing tanto para comprimento como para densidade dos traços. Os dados de comprimento dos traços de fissão foram utilizados para obter os parâmetros do modelo de cinética de annealing para o epídoto. O modelo utilizado foi o proposto pelo grupo de Cronologia da UNICAMP. Cálculos baseados nesses ajustes conduziram a uma previsão de zona de annealing parcial (ZAP) entre 218 a 588°C (para 1 Ma). Quando unidos com os dados de annealing para epídoto de Curvo (2005) a zona de annealing parcial prevista varia de 218 a 487°C (para 1 Ma). Esses valores situam a ZAP para tracos de fissão armazenados no epídoto acima da ZAP para a apatita e sobreposta a ZAP do zircão (possuindo, contudo o limite superior da ZAP acima da do zircão). Uma nova curva de ataque químico foi confeccionada com intenção de se utilizar uma menor temperatura do reagente (15°C, 40% HF). Nove pontos de ataque químico foram realizados, em tempos que variam de 30 a 110 minutos. O tempo estabelecido como ótimo foi 80 minutos. Realizou-se também, uma tentativa de datação de uma amostra de fratura localizada nas redondezas do município de Curitiba. A idade aparente encontra da foi de 240±209 Ma / Abstract: This paper presents studies conducted on the annealing of fission tracks in the epidote. The experiments were done by heating the mineral in time periods of 1, 10 and 100 hours, varying the temperature between 350 and 950°C.The results obtained were annealing curves both for length and for density of the fission tracks. The length data of the fission tracks were used to obtain the parameters for the annealing kinetics model of the epidote. The kinetic model for fission track used was the one proposed by the UNICAMP Chronology group. The mathematical calculations based on these adjustments led to a prediction of a partial annealing zone (PAZ) between 218 and 588°C (for 1 Ma).When united with the data for epidote annealing from Curvo (2005) the partial annealing zone varies from 218 to 487°C (for 1 Ma).These values situate the epidote PAZ above the apatite PAZ and having an intersection with the zircon one (presenting however an upper limit superior to the zircon PAZ).A new etching curve was measured aiming at a lower reagent temperature (15°C, 40% HF). Nine etching points were carried out in time periods ranging from 30 to 110 minutes. The optimal etching time was 80 minutes. An attempt to date an epidote fracture sample located near the city of Curitiba was also conducted. The dating provided the apparent age of 240±209 Ma / Mestre

Esse trabalho tem dois objetivos principais: o primeiro deles consiste em apresentar o estado da arte sobre processos de otimização combinatorial dando uma ênfase especial ao método Simulated Annealing (SA). São apresentados seu histórico, funcionalidades, algoritmo genérico e propostas de paralelização presentes na literatura. Além disso, é apresentado o algoritmo de geração de redes aleatórias contínuas, algoritmo, esse, projetado por pesquisadores do Instituto de Física da UFRGS que utiliza o método SA para gerar redes que atendam certas restrições. O segundo objetivo consiste empropor a paralelização desse algoritmo visando diminuir significativamente o tempo de geração de cada rede, que com o algoritmo seqüencial chega a demorar mais de um mês. Nessa etapa foi utilizada uma adaptação de um dos métodos propostos pela literatura juntamente com a técnica de divisão de domínio. Os resultados obtidos mostraram-se satisfatórios tanto em relação à qualidade numérica quanto à diminuição do tempo de processamento. Além disso, discute-se no trabalho a genericidade da proposta de paralelização a outros problemas baseados em SA. / This work has two main goals: the first one is to present the state of the art on combinatorial optimization processes, with a special emphasis to the Simulated Annealing (SA) method. The work presents its history, features, generic algorithm and proposed parallelization present in the literature. Moreover, the algorithm to generate random networks continued is presented. This algorithm was designed by researchers of the UFRGS Physics Institute and it uses the SA method. The second goal of this work is to propose a parallelization for this algorithm in order to decrease significantly the generation time of each network, that with the sequential algorithm reaches more than months. To do that was used an adaptation of one of the methods proposed by literature together with the domain partitioning technical. The results were satisfactory in terms of the numerical quality and in the decrease of the processing time. In addition, this work discusses the genericity of the proposed parallelization to other problems based on SA.

Crude oil distillation is an energy intensive and environmentally challenging process. To decrease the large energy demand of crude oil distillation, heat integration is implemented. The system (i.e. distillation unit and heat exchanger network, HEN) needs to perform an energy-efficient separation in a broad range of scenarios (e.g. changes in product yields or product specifications), without compromising overall profit. Operational optimisation and revamp projects are frequently implemented to adapt an existing system to such diverse scenarios. The present work provides a new approach for optimising crude oil distillation systems. The scope of this methodology consists of: 1) finding the operating conditions for the distillation system that maximise net profit, while 2) proposing retrofit modifications for the HEN that allow a feasible operation. Artificial neural networks (ANN) are used to represent the distillation process. In the proposed modelling strategy, results of rigorous simulations provide the data used to train the ANN models. The resulting ANN models have the advantages of overcoming convergence problems presented by both rigorous and simplified models, of handling fewer variables and performing calculations in less time. The HEN models used in this work consist of a retrofit model and a simulation model. The HEN retrofit model employed by Chen (2008) is extended to include constraints on heat transfer areas, utility consumption; and to optimise stream split fractions. In addition, the segmented linear data used by Chen (2008) to calculate temperature-dependent heat capacities are replaced by models tailor-made for each stream. This allows a more flexible and accurate representation of these properties, compared to the approach of Chen (2008). The HEN simulation model of de Oliveira Filho et al. (2007) is modified and extended in this work to simulate simple unit operations and to consider heat exchangers specified in terms of heat loads. Distillation, HEN and economic models are implemented in a two-level optimisation framework. The first level consists of a simulated annealing algorithm that optimises the operating conditions of the distillation unit (e.g. flow rates of products and stripping steam, pump-around duties and temperature drops, furnace exit temperature) and HEN topology (i.e. number and location of heat exchangers and stream splitters). The second level solves a non-linear least squares problem that addresses the violation of HEN constraints. Different objective functions can be considered, such as maximising net profit or minimising total annualised costs. The case studies presented in this work show that ANN models are suitable for their implementation in optimisation methodologies for crude oil distillation systems. Results indicate that interactions between the distillation process and HEN are captured, and that significant economic improvements can be achieved with the proposed optimisation approach.

En el proceso de diseño e las construcciones industriales, es de vital importancia conocer cual es la ubicación óptima de las diferentes áras de trabajo que conforman un proceso de fabricación, así como de las instalaciones y servicios auxiliares. El problema de distribución en planta (Facilities Layout Problem, FLP) integra a todas las actividades industriales y se ha convertido desde los años 60 en uno de los problemas clásicos de optimización combinatoria, en el que trabajan multiutd de investigadores a nivel internacional. Hasta los años 90, el enfoque que se realizaba del problema era básicamente un enfoque monobjetivo, en el que se primaba fundamentalmente la minimización del coste de transporte de material o personas entre las diferentes áreas productivas o de servicios. Para ello se han venido empleando diferentes técnicas de optimización heurística, que persiguen minimizar el tiempo de cálculo y facilitar la búsqueda de mínimos, aunque sean locales, pues el espacio de soluciones es tan grande, que es difícil garantizar la existencia de un mínimo global del problema. No obstante, el criterio de coste no es el único que se debe considerar en este tipo de planteamientos, pues existen otra serie de indicadores que son de vital importancia, para garantizar que la solución propuesta tiene un nivel de desarrollo tecnológico con la aparición de equipos y programas informáticos más desarrollados, han prosperado las aproximaciones multiobjetivos al problema de distribución en planta. Entre los objetivos principales del presente trabajo se encuentran; la realización de un estado del arte de los indicadores que se han empleado en la bibliografía para la resolución en planta, obteniendo un conjunto de indicadores independientes y suficientes que puedan ser empleados en la obtención de distribuciones en planta óptimas. Se investigará si es necesario definir algún nuevo indicador que cubra los objetivos fundamentales de la distribución en planta establecidos por distintos autores. Una vez seleccionados los indicadores se propone una técnica de optimización multiobjetivo basada en un algoritmo de recocido simulado (Simulated Annealing). Finalmente se presentan los resultados de los experimentos realizados, empleando la técnica de optimización multiobjetivo propuesta, sobre un problema ampliamente utilizado en la bibliografía, el propuesto por Armour y Buffa de 20 actividades. Se obtienen las fronteras de Pareto para diferentes bicriterios, introduciendo puntos que completan las existentes hasta la actualidad, estudiando la posibilidad de extender la optimización a 3 indicadores. / Montalva Subirats, JM. (2011). Optimización multiobjetivo de la distribución en planta de procesos industriales. Estudio de objetivos [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/11147 / Palancia

The research shows a novel approach for the Magnetic Anomaly Differentiation and Localization Algorithm, which simultaneously localizes multiple magnetic anomalies with weak total field signatures (tens of nT). In particular, it focuses on the case where there are two homogeneous targets with known magnetic moments. This was done by analyzing the magnetic signals and adapting Independent Component Analysis (ICA) and Simulated Annealing (SA) to solve the problem statement. The results show the groundwork for using a combination of fastICA and SA to give localization errors of 3 meters or less per target in simulation and achieved a 58% success rate. Experimental results experienced additional errors due to the effects of magnetic background, unknown magnetic moments, and navigation error. While one target was localized within 3 meters, only the latest experimental run showed the second target approaching the localization specification. This highlighted the need for higher signal-to-noise ratio and equipment with better navigational accuracy. The data analysis was used to provide recommendations on the needed equipment to minimize observed errors and improve algorithm success. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

Metaheuristics are used to find feasible solutions to hard Combinatorial Optimization Problems (COPs). Constraint Satisfaction Problems (CSPs) may be formulated as COPs, where the objective is to reduce the number of violated constraints to zero. The popular puzzle Sudoku is an NP-complete problem that has been used to study the effectiveness of metaheuristics in solving CSPs. Applying the Simulated Annealing (SA) metaheuristic to Sudoku has been shown to be a successful method to solve CSPs. However, the ‘easy-hard-easy’ phase-transition behavior frequently attributed to a certain class of CSPs makes finding a solution extremely difficult in the hard phase because of the vast search space, the small number of solutions and a fitness landscape marked by many plateaus and local minima. Two key mechanisms that metaheuristics employ for searching are diversification and intensification. Diversification is the method of identifying diverse promising regions of the search space and is achieved through the process of heating/reheating. Intensification is the method of finding a solution in one of these promising regions and is achieved through the process of cooling. The hard phase area of the search terrain makes traversal without becoming trapped very challenging. Running the best available method - a Constraint Propagation/Depth-First Search algorithm - against 30,000 benchmark problem-instances, 20,240 remain unsolved after ten runs at one minute per run which we classify as very hard. This dissertation studies the delicate balance between diversification and intensification in the search process and offers a hybrid SA algorithm to solve very hard instances. The algorithm presents (a) a heating/reheating strategy that incorporates the lowest solution cost for diversification; (b) a more complex two-stage cooling schedule for faster intensification; (c) Constraint Programming (CP) hybridization to reduce the search space and to escape a local minimum; (d) a three-way swap, secondary neighborhood operator for a low expense method of diversification. These techniques are tested individually and in hybrid combinations for a total of 11 strategies, and the effectiveness of each is evaluated by percentage solved and average best run-time to solution. In the final analysis, all strategies are an improvement on current methods, but the most remarkable results come from the application of the “Quick Reset” technique between cooling stages.

Indiana University-Purdue University Indianapolis (IUPUI) / Computer Numerical Control (CNC) is widely used in many industries that needs high speed machining of the parts with high precision, accuracy and good surface finish. In order to avail this the generation of the CNC part program size will be immensely big and leads to an inefficient process, which increases the delivery time and cost of products. This work presents the automation of high-accuracy CNC tool trajectory planning from CAD to G-code generation through optimal NURBs surface approximation. The proposed optimization method finds the minimum number of NURBS control points for a given admissible theoretical cord error between the desired and manufactured surfaces. The result is a compact part program that is less sensitive to data starvation than circular and spline interpolations with potential better surface finish. The proposed approach is demonstrated with the tool path generation of an involute gear profile and a topologically optimized structure is developed using this approach and then finally it is 3D printed.