Mestrado em Informática
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Navegando Mestrado em Informática por Autor "Alvarenga, Arlindo Gomes de"
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- ItemA novel cooperative algorithm for clustering large databases with sampling(Universidade Federal do Espírito Santo, 2012-07-30) Fabris, Fábio; Varejão, Flávio Miguel; Alvarenga, Arlindo Gomes de; Barbosa, Hélio José Corrêa; Rodrigues, Alexandre LoureiroClustering is a recurrent task in data mining. The application of traditional heuristics techniques in large sets of data is not easy. They tend to have at least quadratic complexity with respect to the number of points, yielding prohibitive run times or low quality solutions. The most common approach to tackle this problem is to use weaker, more randomized algorithms with lower complexities to solve the clustering problem. This work proposes a novel approach for performing this task, allowing traditional, stronger algorithms to work on a sample of the data, chosen in such a way that the overall clustering is considered good.
- ItemEscalonamento de projetos com restrições de recursos e múltiplos modos de processamento: soluções heurísticas e uma aplicação à programação de manutenção industrial(Universidade Federal do Espírito Santo, 2009-06-25) Cravo, Gildásio Lecchi; Alvarenga, Arlindo Gomes de; Ahonen, Hannu Tapio; Ribeiro, Glaydston Mattos; Lorenzoni, Luciano LessaThis master's thesis presents an implementation of the GRASP meta-heuristic for solving the Multi-mode Resource constrained Problem of Scheduling Project (MRCPSP). The MRCPSP belongs to the class NP-Hard and therefore has received attention of many researchers. In this thesis, a case study problem of Scheduling Industrial Maintenance is viewed as a MRCPSP. The GRASP was tested with a set of benchmark tests obtained from PSPLIB (Project Scheduling Library). The results showed that the GRASP is a good strategy for solving MRCPSP instances.
- ItemMultiplex: um procedimento baseado em simulted annealing aplicado ao problema Max-Sat ponderado(Universidade Federal do Espírito Santo, 2006-04-07) Teixeira, Giovany Frossard; Provedel, Attílio; Alvarenga, Arlindo Gomes de; Ochi, Luiz Satoru; Ahonen, Hannu Tapioabstract
- ItemProblemas de layout: aplicações para o CAP e para o DRLP(Universidade Federal do Espírito Santo, 2016-11-08) Permanhane, Rafael Marin; Amaral, André Renato Sales; Boeres, Maria Claudia Silva; Alvarenga, Arlindo Gomes de; Ahonen, Hannu Tapioabstract
- ItemProcedimentos heurísticos para o problema de escalonamento de projetos com restrição de recursos e múltiplos modos de processamento: uma aplicação na elaboração do cronograma de atualização tecnológica de uma rede de agências bancárias(Universidade Federal do Espírito Santo, 2009-08-26) Jesus, Westley Batista de; Alvarenga, Arlindo Gomes de; Ahonen, Hannu Tapio; Krohling, Renato Antonio; Conceição, Samuel VieiraThe multi-mode resource constrained project scheduling problem (MMRCPSP), is an extension of the resource constrained project scheduling problem (RCPSP), where the activities should be implemented in one of their modes, respecting their precedence and resource constraints. The difficulty of solving the problem, due to its complexity, together with its great practical applicability, because several problem of various areas can be solved by MMRCPSP, have attracted the attention of researchers which has developed several methods to solve the same. In this work two procedures have been proposed, one based on the metaheuristic Simulated Annealing (Simulated Annealing) and the other on Variable Neighborhood Search (Search in Variable Neighborhood), testing them, with instances of the library PSPLIB to verify the quality of the results.
- ItemProgramacão em dois níveis: teoria e algoritmos(Universidade Federal do Espírito Santo, 2010-03-18) Secchin, Leonardo Delarmelina; Alvarenga, Arlindo Gomes de; Ahonen, Hannu Tapio; Krohling, Renato Antonio; Luna, Henrique Pacca LoureiroThis work gives a rigorous approach of bilevel problems, especially the linear case. Proofs of known results in the literature are reproduced or remade. As motivation for the reader, classic problems are reformulated as bilevel problems. In theoretical point of view, some contributions are the formalization of relations between models of literature; their extensions to multilevel problems; the result that complements the equivalence between optimal solutions of the models in linear optimistic case; and the generalization of the method of Calamai and Vicente for generation of linear test problems. In practical point of view, the contribution is a new algorithm for local optimal solutions of linear problems, which differs from other methods in generality: treat unlimited problems, and only requires that the problem s polyhedron does not have degenerate faces.
- ItemSistema imune artificial para o problema de escalonamento Job Shop(Universidade Federal do Espírito Santo, 2006-11-29) Ribeiro, Sildenir Alves; Alvarenga, Arlindo Gomes de; Ahonen, Hannu Tapio; Provedel, Attílio; Conceição, Samuel VieiraThis work presents an Artificial Immune System (AIS) to deal with problems scheduling. The Artificial Immunologic System developed in this project was based on the structure, architecture and functioning of the Biological or Natural Immune Systems. The use of Genetic Algorithm (GA) became necessary to represent the antibodies and antigens of the AIS. Each individual generated for the GA represented a processed task set library in a set of machines. The evaluation of each individual was given by a fitness function that represents the process of natural selection. The evolution of the individuals, and population as a consequence was obtained by applying the genetic operators of crossover e mutation. The machines and the tasks used for the scheduling represent the problem of Job Shop Scheduling (JSS). Some classic tests of the literature where applied to the problem in order to verify the viability of the AIS on the treatment of task of scheduling problems. Those tests also demonstrated the system s behavior its entire execution, therefore, allowing for a detailed analysis of the system s functionalities sets for certain time period. The representation of the natural immunologic systems through computational algorithms inspires from all over world researchers. The motivation is that the immunologic systems possess parallelism characteristics adaptability and learning, which can be applied in several problems found in many areas, had its portability.
- ItemTeoria espectral e o problema de isomorfismo de grafos regulares(Universidade Federal do Espírito Santo, 2011-08-29) Rodrigues, Diego Barcelos; Boeres, Maria Claudia Silva; Rangel, Maria Cristina; Alvarenga, Arlindo Gomes de; Abreu, Nair Maria Maia deSpectral Graph Theory (SGT) studies graph properties by graph representation matrix and its spectrum. A property from SGT, the eigencentrality, provides an important invariant to Graph Isomorphism Problem: if two graphs are isomorphic, they have proportional eigencentralities. However, this property can not be directly used for solving the Regular Graph Isomorphism Problem (RGIP), as every regular graph has the same eigencentralities. This work presents a strategy for solving the RGIP through the use of eigencentralities to prune the search tree and restricting the possibilities for mapping.
- ItemUm estudo da eficiência da autocentralidade no problema de isomorfismo de grafos(Universidade Federal do Espírito Santo, 2012-01-27) Baroni, Marcos Daniel Valadão; Rangel, Maria Cristina; Boeres, Maria Claudia Silva; Alvarenga, Arlindo Gomes de; Justel, Claudia MarcelaThis work treats the application of the eigenvector centrality in solving the Graph Isomorphism Problem. This property, taken from spectral graph theory, was used by Philippe Santos in [SANTOS 2010] to propose a spectral algorithm for solving this problem. An adaptation of the power method is proposed to compute the eigenvector centrality, producing a competitive version to the spectral algorithm of [SANTOS 2010]. Based on this adaptation, the efficiency of the eigenvector centrality in solving the problem is studied. In addition, it is proposed an iterative labeling algorithm, called Centrality Based Iterative Algorithm, which can be applied to any type of graph, including regular ones. Several tests are performed to compare the two proposed algorithms with some others well-known algorithms from literature, such as Nauty.
- ItemUma abordagem em análise de cluster para problemas de agrupamento de áreas florestais(Universidade Federal do Espírito Santo, 2004-09-27) Moura, Alexsandro Afonso; Ahonen, Hannu Tapio; Alvarenga, Arlindo Gomes de; Lorenzoni, Luciano Lessaabstract
- ItemUma abordagem heurística para o problema de otimização de distrito postal(Universidade Federal do Espírito Santo, 2006-06-23) Fiório, Rafael Carpanedo; Alvarenga, Arlindo Gomes de; Provedel, Attílio; Lorenzoni, Luciano Lessa; Conceição, Samuel VieiraThis study proposes a strategia solution for the optimized construction of postal districts. Postal District is a set of segments of publics areas connecteds. Given a locality composed of uncounted segments of publics areas, this study proposes an arrangement of connects subgroups of publics areas with the goal of composing a postal district. The strategy is to transform the system of public areas of a place in a graph and from this graph, to extract their respective cyclical subgraphs that are understood as atomics entities. Those atomics entities are submited by an assembly process until compose a group of postal districts. The methodology here presented divides the study in two different phases: the first one understands the process of obtaining of the cyclical subgraphs; and the second one is understood as the assembly process of postal district The process of obtaining of cyclical subgraph consists in the obtaining of the hull convex of the graph and subsequent extracting up the cyclical subgraphs tangent to edge of that. That is, in a sequential way, in other words, it is determined the first convex hull of the graph and extract up their respective tangent subgraphs; it is determined the second convex hull and extract up their subgraphs and so forth. The study of determination of the convex hull and extracting of the cyclical subgraphs is done through operations of the computational geometry. The process of construction of the postal districts is given through the clustering of the cyclicals subgraphs, using as a tool the meta- heuristic Simulated Annealing. The Chinese Postman's Problem and Capacited Chinese Postman's Problem are formulations support for the present study. The main objective of the study is to obtain, in a fast and efficient way the optimized postal district, with smaller unproductive course possible, offering agility for the process of domiciliary distribution of postal objects.
- ItemUma abordagem usando evolução diferencial para solucionar problemas de programação em dois níveis não lineares(Universidade Federal do Espírito Santo, 2012-08-31) Segundo, Gilberto Alves Santos; Krohling, Renato Antonio; Alvarenga, Arlindo Gomes de; Coelho, Guilherme PalermoBi-level optimization problems occur in several areas, for example: game theory, control, economics, design, etc. Bi-level optimization problems are considered difficult to solve, especially the nonlinear ones. Many approaches to solve linear, differentiable or convex bi-level problems have been proposed and work with relative efficiency and effectiveness. However, there are few methods for solving nonlinear, non-differentiable and non convex bi-level problems. Many of these methods solve only a subclass of the problem, such as problems with linear constraints or only with the function of the leader being nonlinear. This study proposes a novel approach using Differential Evolution to solve nonlinear bi-level problems in general. In addition, this work develops a method for constraint handling, present in bi-level programming problems. Promising results have been obtained, showing the effectiveness of the approach.