Encontrados 24 documentos, a visualizar página 1 de 3
A hybrid genetic pattern search augmented Lagrangian method for constrained glo...
Costa, L.; Espírito Santo, I. A. C. P.; Fernandes, Edite Manuela da G. P.Hybridization of genetic algorithms with local search approaches can enhance their performance in global optimization. Genetic algorithms, as most population based algorithms, require a considerable number of function evaluations. This may be an important drawback when the functions involved in the problem are computationally expensive as it occurs in most real world problems. Thus, in order to reduce the total...
Heuristic pattern search for bound constrained minimax problems
Espírito Santo, I. A. C. P.; Fernandes, Edite Manuela da G. P.This paper presents a pattern search algorithm and its hybridization with a random descent search for solving bound constrained minimax problems. The herein proposed heuristic pattern search method combines the Hooke and Jeeves (HJ) pattern and exploratory moves with a randomly generated approxi- mate descent direction. Two versions of the heuristic algorithm have been applied to several benchmark minimax probl...
Uncertainty on multi-objective optimization problems
Costa, L.; Espírito Santo, I. A. C. P.; Oliveira, PedroIn general, parameters in multi-objective optimization are assumed as deterministic with no uncertainty. However, uncertainty in the parameters can affect both variable and objective spaces. The corresponding Pareto optimal fronts, resulting from the disturbed problem, define a cloud of curves. In this work, the main objective is to study the resulting cloud of curves in order to identify regions of more robust...
Using a genetic algorithm to solve a bi-objective WWTP process optimization
Costa, L.; Espírito Santo, I. A. C. P.; Fernandes, Edite Manuela da G. P.; Denysiuk, RomanWhen modeling an activated sludge system of a wastewater treatment plant (WWTP), several conflicting objectives may arise. The proposed formulation is a highly constrained bi-objective problem where the minimization of the investment and operation costs and the maximization of the quality of the effluent are simultaneously optimized. These two conflicting objectives give rise to a set of Pareto optimal solution...
Stochastic algorithms assessment using performance profiles
Costa, L.; Espírito Santo, I. A. C. P.; Oliveira, PedroOptimization with stochastic algorithms has become a relevant approach, specially, in problems with complex search spaces. Due to the stochastic nature of these algorithms, the assessment and comparison is not straightforward. Several performance measures have been proposed to overcome this difficulty. In this work, the use of performance profiles and an analysis integrating a trade-off between accuracy and pre...
Optimização de um sistema de lamas activadas por um algoritmo genético
Espírito Santo, I. A. C. P.; Costa, L.; Denysiuk, Roman; Fernandes, Edite Manuela da G. P.Apresenta-se, neste artigo, um problema de optimização relacionado com um processo biológico de tratamento de águas residuais. A formulação matemática que surge da modelação de um sistema de lamas activadas de uma ETAR é optimizado, em termos de custos de investimento e custos operacionais, através de um algoritmo genético. É usado o modelo ASM1 para as lamas activadas, um dos modelos matemáticos mais difundido...
Hybrid genetic pattern search augmented Lagrangian algorithm : application to W...
Espírito Santo, I. A. C. P.; Costa, L.; Denysiuk, Roman; Fernandes, Edite Manuela da G. P.An augmented Lagrangian algorithm is presented to solve a global optimization problem that arises when modeling the activated sludge system in a Wastewater Treatment Plant, attempting to minimize both investment and operation costs. It is a heuristic-based algorithm that uses a genetic algorithm to explore the search space for a global optimum and a pattern search method for the local search refinement. The obt...
Wasted sludge treatment contributions in the WWTP total cost
Espírito Santo, I. A. C. P.; Fernandes, Edite Manuela da G. P.; Araújo, Maria Madalena Teixeira de; Ferreira, E. C.This paper aims to analyze the cost contribution of a simple wasted sludge process in the WWTP design total cost. The plant design relies on a combined ATV and double exponential model to describe the secondary settler as well as on a simple sludge treatment based on dewatering followed by deposition in landfills. The experiments carried out with three small WWTPs in design show that the chosen wasted biosolids...
Cost minimization of a WWTP using an augmented lagrangian pattern search based ...
Espírito Santo, I. A. C. P.; Fernandes, Edite Manuela da G. P.; Araújo, M. Manuela; Ferreira, E. C.This paper describes a derivative-free method that aims to solve an optimization problem arising from the mathematical formulation of an activated sludge system in which the objective is to minimize the investment and operation costs. The method relies on an augmented Lagrangian technique that uses a pattern search for solving bound constrained subproblems.
Desenho óptimo de estações de águas resíduais através da modelação de funções d...
Espírito Santo, I. A. C. P.Tese de Doutoramento em Engenharia de Produção de Sistemas, área de Métodos Númericos e Estatísticos ; Uma das grandes preocupações actuais prende-se com a preservação do meio ambiente. Em particular, no caso do tratamento de efluentes líquidos domésticos e/ou industriais, cujo impacto ambiental é muito significativo, é conveniente fazer-se uma análise detalhada aos efluentes em causa e aos processos de tratam...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||