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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.
1

Uso de Algoritmos EvolucionÃrios na CalibraÃÃo de Modelos HidrolÃgicos e na OperaÃÃo de Sistemas de ReservatÃrios / Use of evolutionary algorithms on hydrologic model calibration and on operation of reservoir systems

Francisco VenÃcius Fernandes Barros 31 July 2007 (has links)
A experiÃncia tem mostrado que buscas de Ãtimos baseadas em apenas um objetivo, por mais cuidadosas que sejam, nÃo conseguem determinar uma soluÃÃo que modele satisfatoriamente um dado fenÃmeno. O uso de abordagens multiobjetivo pode ainda ser justificado pela natureza dos problemas reais, a qual requer a utilizaÃÃo de mÃltiplos objetivos, muitas vezes conflitantes. Um conceito muito utilizado neste contexto à o de dominÃncia de Pareto, a qual possibilita comparar soluÃÃes usando mÃltiplos objetivos e explorar diferentes caracterÃsticas dos dados observados. Este trabalho tem como foco a aplicaÃÃo de algoritmos evolucionÃrios baseados no acasalamento de abelhas em sua versÃo uni- (Honey-Bee Mating Optimization - HBMO) e multiobjetivo (Multiobjective Honey-Bee Mating Optimization - MOHBMO) na minimizaÃÃo de funÃÃes-teste, calibraÃÃo de modelos hidrolÃgicos e otimizaÃÃo da operaÃÃo de sistemas de reservatÃrios. A versÃo uniobjetivo à aquela proposta por Haddad et al. (2006), enquanto a multiobjetivo à uma proposiÃÃo do presente trabalho. Como algoritmos de referÃncia da performance foram utilizados: PSO (Particle Swarm Optimization), sua versÃo multiobjetivo MOPSO (Multiobjective Particle Swarm), SCEM (Shuffled Complex Evolucion Metropolis) e sua versÃo multiobjetivo MOSCEM (Multiobjective Shuffled Complex Evolucion Metropolis). AplicaÃÃes teÃricas foram realizadas pela minimizaÃÃo de problemas compostos por funÃÃes matemÃticas encontradas na literatura. AplicaÃÃes reais de calibraÃÃo de modelos hidrolÃgicos e operaÃÃes de sistemas de reservatÃrios tiveram como estudo de caso a calibraÃÃo dos modelos HYMOD e SMAP a nÃvel diÃrio para 15 estaÃÃes fluviomÃtricas localizadas nos estados do Cearà e Piauà e a otimizaÃÃo da operaÃÃo do sistema de reservatÃrios que compÃem o sistema de abastecimento de Ãgua da RegiÃo Metropolitana de Fortaleza, respectivamente. / Experience suggests that any single-objective search, no matter how carefully chosen, is not able to identify a solution capable of satisfactorily model a phenomenum of interest. Use of a multiobjective approach can yet be justified by the nature of real world problems, which in general involve multiobjectives, most of the time conflicting objectives. An approach very often used in multicriteria optimization is the concept of Pareto dominance, which allows us to compare different solutions by using different objectives and to explore different characteristics of the observed data. This dissertation employs evolutionary algorithms inspired on honey-bee mating for single (Honey-Bee Mating Optimization - HBMO) e multiobjectives (Multiobjective Honey-Bee Mating Optimization - MOHBMO) in the minimization of test functions and calibration of watershed models. The singleobjective version is the one introduced by Haddad et al. (2006), while its multiobjective version is proposed by the present work. As reference of their performance, the following algorithms were used: PSO (Particle Swarm Optimization), and its multiobjective version MOPSO (Multiobjective Particle Swarm), SCEM (Shuffled Complex Evolucion Metropolis) and its multiobjective version MOSCEM (Multiobjective Shuffled Complex Evolucion Metropolis). Well known theoretical functions were used to test the proposed algorithms. Real world applications on hydrologic model calibration employing HYMOD and SMAP models, with daily time steps, were carried out for 15 streamflow gauge stations located in the states of Cearà e PiauÃ. Besides, an optimization study for the operation of the reservoir system that supplies water for the Metropolitan Region of Fortaleza was also executed.

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