Maria Claudia Silva Boeres
Universidade Federal do Espírito Santo
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Featured researches published by Maria Claudia Silva Boeres.
Lecture Notes in Computer Science | 2004
Maria Claudia Silva Boeres; Celso C. Ribeiro; Isabelle Bloch
We propose a new strategy for solving the non-bijective graph matching problem in model-based pattern recognition. The search for the best correspondence between a model and an over-segmented image is formulated as a combinatorial optimization problem, defined by the relational attributed graphs representing the model and the image where recognition has to be performed, together with the node and edge similarities between them. A randomized construction algorithm is proposed to build feasible solutions to the problem. Two neighborhood structures and a local search procedure for solution improvement are also proposed. Computational results are presented and discussed, illustrating the effectiveness of the combined approach involving randomized construction and local search.
Brazilian Symposium on Computers in Education (Simpósio Brasileiro de Informática na Educação - SBIE) | 2009
Juliana Hiroko Kowata; Davidson Cury; Maria Claudia Silva Boeres
In the presence of the actual world context, the importance of knowing the technological resources and making use of them to improve the performance of human activities is realized. Educat ion cannot be laid aside of this reality, on the contrary, it has to be allied and seek for resources to improve even more the process of teaching and learn ing through Information and Communication Technologies (ICTs). Thus, the dof Araucaria/PR, through the Educational Technology Project, has pro vided access to these resources establishing informatics laboratories, ev aluating and reorganizing the used method, as an example, the accomplishment of the Leader-Teacher function related to the laboratory monitor one. Resumo. Diante do contexto do mundo atual, percebe-se a imp ortância de conhecer os recursos tecnologicos e fazer uso deste s para melhorar o desempenho das atividades humanas. A educacao nao pficar a margem desta realidade, ao contrario, deve buscar meios de aprimorar o processo de ensino e aprendizagem por meio das Tecnologias da I nformacao e Comunicacao (TICs). Assim, o municipio de Araucari a/PR, atraves do Projeto de Tecnologia Educacional, tem viabilizado o acesso a estes recursos com a implantacao de laboratorios de informatica, ae reorganizando os metodos empregados, como por exemplo, a implemen tacao da funcao de Professor-orientador em detrimento a funcao do moni tor de laboratorio.
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2015
Edmar Hell Kampke; Walace de Souza Rocha; Maria Claudia Silva Boeres; Maria Cristina Rangel
The timetabling problem is of great interest in the combinatorial optimization field. Given a set of disciplines, students, teachers and classrooms, the problem lies in allocating lectures in a limited number of timeslots and rooms respecting a set of constraints. In this paper, we propose a GRASP algorithm for the university timetabling formulated at ITC-2007. Hill Climbing and Simulated Annealing techniques are used as GRASP local search procedures and path relinking is implemented to improve its basic version. Computational tests were carried out, simulating the ITC-2007 competition rules and the results obtained are competitive.
international conference on computational science and its applications | 2017
Edmar Hell Kampke; Erika Almeida Segatto; Maria Claudia Silva Boeres; Maria Cristina Rangel; Geraldo Regis Mauri
Metaheuristics define and explore a set of different neighborhoods, in general, adapted to specific characteristics of a problem. The quality of the solution found relies on the efficiency of the neighborhood used on the local search phase, therefore it is very important to research about the movements or combination of them which compose the neighborhood structure. This paper is based on a recent work reported on literature that deals with four standard movements for the university timetabling problem. This work complements the analysis already done so far, adding five new movements widely known in the literature. Two of then are specific for the restrictions adopted by the curriculum-based formulation proposed on the Second International Timetabling Competition (ITC-2007). The Steepest Descent (SD) algorithm was implemented to study each movement separately and combined. This analysis shows that the quality of the solutions is highly affected by the movements chosen, since the ratio between the worst and best solution (in terms of objective function value), can be up to 13.5.
international conference on computational science and its applications | 2017
Leonardo Muniz de Lima; Lucia Catabriga; Maria Cristina Rangel; Maria Claudia Silva Boeres
In this paper we apply the parallel hybrid SPIKE algorithm as a preconditioner for a nonstationary iterative method to solve large sparse linear systems. In order to obtain a good preconditioner, we employ several strategies solving combinatorial problems such as matching, reordering, partitioning, and quadratic knapsack. Our SPIKE implementation combines MPI and OpenMP paradigms in a unique multi-core computer. The computational experiments show the influence of each strategy evaluating the number of iterations and CPU time of the iterative solver in a set of large systems from miscellaneous application areas. The experiments suggest that the SPIKE preconditioner is very advantageous when a suitable set of parameters is chosen. The choice of the number of MPI ranks and OpenMP threads is not an easy task, because the SPIKE algorithm can increase the number of iterations when the number of MPI ranks grows. Moreover, the increase in the number of threads does not ensure a better performance.
federated conference on computer science and information systems | 2017
Thiago Nascimento Rodrigues; Maria Claudia Silva Boeres; Lucia Catabriga
This work presents a new parallel non-speculative implementation of the Unordered Reverse Cuthill-McKee algorithm. Reordering quality (bandwidth reduction) and reordering performance (CPU time) are evaluated in comparison with a serial implementation of the algorithm made available by the state-of-the-art mathematical software library HSL. The bandwidth reductions reached by our parallel RCM were more than 90% for several large matrices out of the ones tested, and the time reordering improvement was up to 57.82%. Speedups higher than 3.0X were achieved with the parallel RCM. The underlying parallelism was supported by the OpenMP framework and three strategies for reducing idle threads were incorporated into the algorithm.
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2017
Thiago Nascimento Rodrigues; Maria Claudia Silva Boeres; Lucia Catabriga
This paper describes an implementation of the Unordered Parallel Reverse Cuthill-McKee algorithm which is compared with its well-known serial version. The OpenMP framework is used for supporting the parallelism and a strategy for reducing lazy threads is evaluated. Large sparse matrices are used to test sequential and parallel approaches. The computational cost reduction and the quality of matrices bandwidth minimization are validated by CPU time and speedup.
Proceeding Series of the Brazilian Society of Computational and Applied Mathematics | 2015
Brenno A. Lugon; Leonardo Muniz de Lima; Marcelo T. P. Carrion; Lucia Catabriga; Maria Cristina Rangel; Maria Claudia Silva Boeres
Neste trabalho, utilizamos o algoritmo paralelo hibrido SPIKE como um precondicionador para um metodo iterativo nao-estacionario combinando as arquiteturas de memoria distribuida e compartilhada MPI/OpenMP. A fim de obter um bom precondicionador resolvemos um conjunto de problemas combinatorios como reordenamento, particionamento, matching e o problema quadratico da mochila. Apresentamos os resultados avaliando o speedup e escalabilidade em sistemas resultantes de formulacoes de elementos finitos.
RENOTE | 2006
Flávio Severiano Lamas de Souza; Maria Claudia Silva Boeres; Davidson Cury; Crediné Silva de Menezes; Guilherme Carlesso
O problema de correspondencia de grafos (PCG) consiste em um problema formulado em Otimizacao Combinatoria para a comparacao estrutural de grafos, a partir da identificacao de similaridades. Proposto inicialmente para aplicacoes em reconhecimento de imagens, pretende-se neste trabalho, adapta-lo para uma aplicacao em recuperacao inteligente de informacao, a saber, a comparacao de mapas conceituais em representacao de conhecimento, assim como investigar a utilizacao de algoritmos heuristicos e exatos para a sua resolucao.
Archive | 2008
F. S. L. De Souza; Maria Claudia Silva Boeres; Davidson Cury; C. S. De Menezes; G. Carlesso