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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Roteamento e alocação de comprimento de onda em redes WDM segundo algoritmo baseado em regras da natureza. / Routing and wavelength allocation in WDM networks through an algorithm based on rules of nature.

Eduardo Rodrigues Benayon 17 December 2012 (has links)
O surgimento de novos serviços de telecomunicações tem provocado um enorme aumento no tráfego de dados nas redes de transmissão. Para atender a essa demanda crescente, novas tecnologias foram desenvolvidas e implementadas ao longo dos anos, sendo que um dos principais avanços está na área de transmissão óptica, devido à grande capacidade de transporte de informação da fibra óptica. A tecnologia que melhor explora a capacidade desse meio de transmissão atualmente é a multiplexação por divisão de comprimento de onda ou Wavelength Division Multiplexing (WDM) que permite a transmissão de diversos sinais utilizando apenas uma fibra óptica. Redes ópticas WDM se tornaram muito complexas, com enorme capacidade de transmissão de informação (terabits por segundo), para atender à explosão de necessidade por largura de banda. Nesse contexto, é de extrema importância que os recursos dessas redes sejam utilizados de forma inteligente e otimizada. Um dos maiores desafios em uma rede óptica é a escolha de uma rota e a seleção de um comprimento de onda disponível na rede para atender uma solicitação de conexão utilizando o menor número de recursos possível. Esse problema é bastante complexo e ficou conhecido como problema de roteamento e alocação de comprimento de onda ou, simplesmente, problema RWA (Routing and Wavelentgh Assignment problem). Muitos estudos foram realizados com o objetivo de encontrar uma solução eficiente para esse problema, mas nem sempre é possível aliar bom desempenho com baixo tempo de execução, requisito fundamental em redes de telecomunicações. A técnica de algoritmo genético (AG) tem sido utilizada para encontrar soluções de problemas de otimização, como é o caso do problema RWA, e tem obtido resultados superiores quando comparada com soluções heurísticas tradicionais encontradas na literatura. Esta dissertação apresenta, resumidamente, os conceitos de redes ópticas e de algoritmos genéticos, e descreve uma formulação do problema RWA adequada à solução por algoritmo genético. / The advent of new telecommunication services resulted in a huge increase of data traffic in the transmission networks. New technologies were developed and implemented over the years to attend to this growing demand, and the optical transmission technology stands. It has advanced greatly, due to the optical fibers large capacity of information transmission. Actually, the best technology to exploits the capacity of the fiber is the wavelength-division multiplexing (WDM), allowing the transmission of multiple signals over a single optical fiber. The WDM optical networks have become very complex, with huge capacity (terabits per second), to attend the ever growing need for bandwidth. In this context, it is extremely important to use the networks resources in an intelligent and optimized way. One of the biggest challenges in an optical network is choosing a route, and selecting a available wavelength on the network to attend a connection request using the least amount of resources. This problem is quite complex, and is known as the routing and wavelength assignment problem or simply RWA problem. Many studies were conducted in order to find an efficient solution to this problem, but it is not always possible to combine good performance with low execution time, a fundamental requirement in telecommunications networks. Genetic Algorithms have been used to solve hard optimization problems, as is the case of the RWA problem, and has produced remarkable results when compared to traditional heuristics found in the literature. This work presents an overview of the concepts of optical networks and genetic algorithms, and describes a formulation of RWA problem that is adequate for solution by genetic algorithm.
12

Roteamento e alocação de comprimento de onda em redes WDM segundo algoritmo baseado em regras da natureza. / Routing and wavelength allocation in WDM networks through an algorithm based on rules of nature.

Eduardo Rodrigues Benayon 17 December 2012 (has links)
O surgimento de novos serviços de telecomunicações tem provocado um enorme aumento no tráfego de dados nas redes de transmissão. Para atender a essa demanda crescente, novas tecnologias foram desenvolvidas e implementadas ao longo dos anos, sendo que um dos principais avanços está na área de transmissão óptica, devido à grande capacidade de transporte de informação da fibra óptica. A tecnologia que melhor explora a capacidade desse meio de transmissão atualmente é a multiplexação por divisão de comprimento de onda ou Wavelength Division Multiplexing (WDM) que permite a transmissão de diversos sinais utilizando apenas uma fibra óptica. Redes ópticas WDM se tornaram muito complexas, com enorme capacidade de transmissão de informação (terabits por segundo), para atender à explosão de necessidade por largura de banda. Nesse contexto, é de extrema importância que os recursos dessas redes sejam utilizados de forma inteligente e otimizada. Um dos maiores desafios em uma rede óptica é a escolha de uma rota e a seleção de um comprimento de onda disponível na rede para atender uma solicitação de conexão utilizando o menor número de recursos possível. Esse problema é bastante complexo e ficou conhecido como problema de roteamento e alocação de comprimento de onda ou, simplesmente, problema RWA (Routing and Wavelentgh Assignment problem). Muitos estudos foram realizados com o objetivo de encontrar uma solução eficiente para esse problema, mas nem sempre é possível aliar bom desempenho com baixo tempo de execução, requisito fundamental em redes de telecomunicações. A técnica de algoritmo genético (AG) tem sido utilizada para encontrar soluções de problemas de otimização, como é o caso do problema RWA, e tem obtido resultados superiores quando comparada com soluções heurísticas tradicionais encontradas na literatura. Esta dissertação apresenta, resumidamente, os conceitos de redes ópticas e de algoritmos genéticos, e descreve uma formulação do problema RWA adequada à solução por algoritmo genético. / The advent of new telecommunication services resulted in a huge increase of data traffic in the transmission networks. New technologies were developed and implemented over the years to attend to this growing demand, and the optical transmission technology stands. It has advanced greatly, due to the optical fibers large capacity of information transmission. Actually, the best technology to exploits the capacity of the fiber is the wavelength-division multiplexing (WDM), allowing the transmission of multiple signals over a single optical fiber. The WDM optical networks have become very complex, with huge capacity (terabits per second), to attend the ever growing need for bandwidth. In this context, it is extremely important to use the networks resources in an intelligent and optimized way. One of the biggest challenges in an optical network is choosing a route, and selecting a available wavelength on the network to attend a connection request using the least amount of resources. This problem is quite complex, and is known as the routing and wavelength assignment problem or simply RWA problem. Many studies were conducted in order to find an efficient solution to this problem, but it is not always possible to combine good performance with low execution time, a fundamental requirement in telecommunications networks. Genetic Algorithms have been used to solve hard optimization problems, as is the case of the RWA problem, and has produced remarkable results when compared to traditional heuristics found in the literature. This work presents an overview of the concepts of optical networks and genetic algorithms, and describes a formulation of RWA problem that is adequate for solution by genetic algorithm.
13

Otimização da função de fitness para a evolução de redes neurais com o uso de análise envoltória de dados aplicada à previsão de séries temporais

SILVA, David Augusto 01 July 2011 (has links)
Submitted by (ana.araujo@ufrpe.br) on 2016-06-28T16:05:18Z No. of bitstreams: 1 David Augusto Silva.pdf: 1453777 bytes, checksum: 4516b869e7e749b770a803eb7e91a084 (MD5) / Made available in DSpace on 2016-06-28T16:05:18Z (GMT). No. of bitstreams: 1 David Augusto Silva.pdf: 1453777 bytes, checksum: 4516b869e7e749b770a803eb7e91a084 (MD5) Previous issue date: 2011-07-01 / The techniques for Time Series Analysis and Forecasting have great presence on the literature over the years. The computational resources combined with statistical techniques are improving the predictive results, and these results have been become increasingly accurate. Computational methods base on Artificial Neural Networks (ANN) and Evolutionary Computing (EC) are presenting a new approach to solve the Time Series Analysis and Forecasting problem. These computational methods are contained in the branch of Artificial Intelligence (AI), and they are biologically inspired, where the ANN models are based on the neural structure of intelligent organism, and the EC uses the concept of nature selection of Charles Darwin. Both methods acquire experience from prior knowledge and example of the given problem. In particular, for the Time Series Forecasting Problem, the objective is to find the predictive model with highest forecast perfomance, where the performance measure are statistical errors. However, there is no universal criterion to identify the best performance measure. Since the ANNs are the predictive models, the EC will constantly evaluate the forecast performance of the ANNs, using a fitness functions to guide the predictive model for an optimal solution. The Data Envelopment Analysis (DEA) was employed to predictive determine the best combination of variables based on the relative efficiency of the best models. Therefore, this work to study the optimization Fitness Function process with Data Envelopment Analysis applied the Intelligence Hybrid System for time series forecasting problem. The data analyzed are composed by financial data series, agribusiness and natural phenomena. The C language program was employed for implementation of the hybrid intelligent system and the R Environment version 2.12 for analysis of DEA models. In general, the perspective of using DEA procedure to evaluate the fitness functions were satisfactory and serves as an additional resource in the branch of time series forecasting. Researchers need to compute the results under different perspectives, whether in the matter of the computational cost of implementing a particular function or which function was more efficient in the aspect of assessing which combinations are unwanted saving time and resources. / As técnicas de análise e previsão de séries temporais alcançaram uma posição de distinção na literatura ao longo dos anos. A utilização de recursos computacionais, combinada com técnicas estatísticas, apresenta resultados mais precisos quando comparados com os recursos separadamente. Em particular, técnicas que usam Redes Neurais Artificiais (RNA) e Computação Evolutiva (CE), apresenta uma posição de destaque na resolução de problemas de previsão na análise de séries temporais. Estas técnicas de Inteligência Artificial (AI) são inspiradas biologicamente, no qual o modelo de RNA é baseado na estrutura neural de organismos inteligentes, que adquirem conhecimento através da experiência. Para o problema de previsão em séries temporais, um fator importante para o maior desempenho na previsão é encontrar um método preditivo com a melhor acurácia possível, tanto quanto possível, no qual o desempenho do método pode ser analisado através de erros de previsão. Entretanto, não existe um critério universal para identificar qual a melhor medida de desempenho a ser utilizada para a caracterização da previsão. Uma vez que as RNAs são os modelos de previsão, a CE constantemente avaliará o desempenho de previsão das RNAs, usando uma função de fitness para guiar o modelo preditivo para uma solução ótima. Desejando verificar quais critérios seriam mais eficientes no momento de escolher o melhor modelo preditivo, a Análise Envoltória de Dados (DEA) é aplicada para fornecer a melhor combinação de variáveis visando a otimização do modelo. Portanto, nesta dissertação, foi estudado o processo de otimização de Funções de Fitness através do uso da Análise Envoltória de Dados utilizando-se de técnicas hibridas de Inteligência Artificial aplicadas a área de previsão de séries temporais. O banco de dados utilizado foi obtido de séries históricas econômico- financeiras, fenômenos naturais e agronegócios obtidos em diferentes órgãos específicos de cada área. Quanto à parte operacional, utilizou-se a linguagem de programação C para implementação do sistema híbrido inteligente e o ambiente R versão 2.12 para a análise dos modelos DEA. Em geral, a perspectiva do uso da DEA para avaliar as Funções de Fitness foi satisfatório e serve como recurso adicional na área de previsão de séries temporais. Cabe ao pesquisador, avaliar os resultados sob diferentes óticas, quer seja sob a questão do custo computacional de implementar uma determinada Função que foi mais eficiente ou sob o aspecto de avaliar quais combinações não são desejadas poupando tempo e recursos.
14

Optimalizace procesů v logistice s podporou vizualizace / Optimization of Processes in Logistics with Visualization Support

Kršák, Martin January 2019 (has links)
The master thesis aims to design, implement, and compare algorithms that optimize processes in logistics, mainly in the planning phase. Heuristics and approximation genetic algorithms will find an near-optimal solution to NP-hard problem, such as the traveling salesman problem, with a delay less than several hours. The role of this algorithm is to plan an efficient route for garbage trucks that collect and distribute large-scale waste to waste yards in a specific city. The goal of the optimization is to minimize the shipping costs.
15

Eliminace zkreslení obrazů duhovky / Suppresion of distortion in iris images

Jalůvková, Lenka January 2014 (has links)
This master`s thesis is focused on a suppression of a distorsion in iris images. The aim of this work is to study and describe existing degradation methods (1D motion blur, uniform 2D motion blur, Gaussian blur, atmospheric turbulence blur, and out of focus blur). Furthermore, these methods are implemented and tested on a set of images. Then, we designed methods for suppression of these distorsions - inverse filtration, Wiener filtration and iterative deconvolution. All of these methods were tested and evaluated. Based on the experimental results, we can conclude that the Wiener-filter restoration is the most accurate approach from our test set. It achieves the best results in both normal and iterative mode.
16

Genetické algoritmy a rozvrhování / Genetic Algorithms and Scheduling

Škrabal, Ondřej January 2010 (has links)
This work deals with scheduling problem in particular plastic production service. The solution is based on heuristic algorithms, programming languages C + +, C # and is built on the .NET framework and LINQ to XML. It provides the users with comparisons of the heuristic approach with genetic algorithms applied to production problem. All methods results are compared in relation to hand-arranged plans.
17

Toolbox pro vícekriteriální optimalizační problémy / Toolbox for multi-objective optimization

Marek, Martin January 2016 (has links)
This paper deals with multi-objective optimization problems (MOOP). It is explained, what solutions in multi-objetive search space are optimal and how are optimal (non-dominated) solutions found in the set of feasible solutions. Afterwards, principles of NSGA-II, MOPSO and GDE3 algorithms are described. In the following chapters, benchmark metrics and problems are introduced. In the last part of this paper, all the three algorithms are compared based on several benchmark metrics.
18

Genetické algoritmy – Multi-core CPU implementace / Genetic Algorithms - Multi-core CPU Implementation

Studnička, Vladimír January 2010 (has links)
his diploma thesis deals with creating the most universal library of genetic algorithms in C++, as much as possible, implemented with the certain number of universal operators, and then with testing created library on some examples. Library must support multi-core processors, implementation will be done over OpenMP. The library will be tested on three examples in all. The first two examples are mathematical functions, that are used just for genetic algorithms testing. Last problem for test is N-Queens problem. Finally we will use genetic algorithms to try find solution for Eternity II puzzle, there is declared a 2 million bounty for full solution.
19

Procedural Generation of Levels with Controllable Difficulty for a Platform Game Using a Genetic Algorithm / Procedurell generering av banor med kontrollerbar svårighetsgrad till ett platformspel med hjälp av en genetisk algoritm

Classon, Johan, Andersson, Viktor January 2016 (has links)
This thesis describes the implementation and evaluation of a genetic algorithm (GA) for procedurally generating levels with controllable difficulty for a motion-based 2D platform game. Manually creating content can be time-consuming, and it may be desirable to automate this process with an algorithm, using Procedural Content Generation (PCG). An algorithm was implemented and then refined with an iterative method by conducting user tests. The resulting algorithm is considered a success and shows that using GA's for this kind of PCG is viable. An algorithm able to control difficulty of its output was achieved, but more refinement could be made with further user tests. Using a GA for this purpose, one should find elements that affect difficulty, incorporate these in the fitness function, and test generated content to ensure that the fitness function correctly evaluates solutions with regard to the desired output.
20

Advanced Raman, SERS, and ROA studies of biomedical and pharmaceutical compounds in solution

Levene, Clare January 2012 (has links)
The primary purpose of this study was to investigate the combination of experimental and computational methods in the search for reproducible colloidal surface-enhanced Raman scattering of pharmaceutical compounds. In the search for optimal experimental conditions for colloidal surface-enhance Raman scattering, the amphipathic β-blocker propranolol was used as the target molecule. Fractional factorial designs of experiments were performed and a multiobjective evolutionary algorithm was used to find acceptable solutions, from the results, that were Pareto ranked. The multiobjective evolutionary algorithm suggested solutions outside of the fractional factorial design and the experiments were then performed in the laboratory. The results observed from the suggested solutions agreed with the solutions that were found on the Pareto front. One of the experimental conditions observed on the Pareto front was then used to determine the practical limit of detection of propranolol. The experimental conditions that were chosen for the limit of detection took into account reproducibility and enhancement, the two most important parameters for analytical detection using surface-enhanced Raman scattering. The principal conclusion to this study was that the combination of computational and experimental methods can reduce the need for experiments by > 96% and then selecting solutions from the Pareto front improved limit of detection by a factor of 24.5 when it was compared to the previously reported limit of detection for propranolol. Using the same experimental conditions that were used for the limit of detection, these experiments were extended to plasma spiked with propranolol in order to test detection of this pharmaceutical in biofluids. Concentrations of propranolol were prepared using plasma as the solvent and measured for detection using colloidal surface-enhanced Raman scattering. Detection was determined as <130 ng/mL, within physiological concentrations, previously achieved using separation techniques. The second part of this thesis also involved a combination of experimental and computational methods. Raman optical activity was utilized to investigate secondary structure of amino acids and diamino acid peptides in combination with density functional theory calculations. Amino acids are important biological molecules that have vital functions in the biological system. They have been recognized as neurotransmitters and implicated in neurodegenerative diseases. Raman and Raman optical activity experimental results were compared to determine site-specific acetylation, marker bands for constitutional isomers and identification of functional groups that interact with the solvent. The experimental spectra were then compared to those from the density functional theory calculations. The results indicated that; constitutional isomers cannot be distinguished from the Raman spectra but can be distinguished from the Raman optical activity spectra, site-specific acetylation can be identified from the Raman spectra, however, Raman optical activity provides more structural information in relation to acetylation. When the results were compared to the density functional theory calculations for the diamino acid peptides the results agreed reasonably well, however, agreement was not as good for the monoamino acids because diamino acid peptides support fewer conformations due to the peptide bond whereas monoamino acids can adopt a far greater number of conformations. Combined computational and experimental techniques have developed the ability to detect and characterize biomedical compounds, a significant move in the advancement of Raman spectroscopies.

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