Parallel Scatter Search Approach for the MinMax Regret Location Problem

2018 ◽  
Vol 9 (2) ◽  
pp. 1-17
Author(s):  
Sarah Ibri ◽  
Mohammed EL Amin Cherabrab ◽  
Nasreddine Abdoune
Keyword(s):  
Location Problem ◽  
Search Algorithm ◽  
Discrete Event ◽  
Scatter Search ◽  
Search Time ◽  
Computation Time ◽  
Minmax Regret ◽  
Search Approach ◽  
Two Stages

In this paper we propose an efficient solving method based on a parallel scatter search algorithm that accelerates the search time to solve the minmax regret location problem. The algorithm was applied in the context of emergency management to locate emergency vehicles stations. A discrete event simulator was used to test the quality of the obtained solutions on the operational level. We compared the performance of the algorithm to an existing two stages method, and experiments show the efficiency of the proposed method in terms of quality of solution as well as the gain in computation time that could be obtained by parallelizing the proposed algorithm.

scholarly journals A Scatter Search Approach for Multiobjective Selective Disassembly Sequence Problem

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Xiwang Guo ◽  
Shixin Liu
Keyword(s):  
Multiobjective Optimization ◽  
Scatter Search ◽  
Nsga Ii ◽  
Disassembly Sequence ◽  
Selective Disassembly ◽  
Local Search Strategy ◽  
Search Approach ◽  
Nondominated Sorting ◽  
Disassembly Time

Disassembly sequence has received much attention in recent years. This work proposes a multiobjective optimization of model for selective disassembly sequences and maximizing disassembly profit and minimizing disassembly time. An improved scatter search (ISS) is adapted to solve proposed multiobjective optimization model, which embodies diversification generation of initial solutions, crossover combination operator, the local search strategy to improve the quality of new solutions, and reference set update method. To analyze the effect on the performance of ISS, simulation experiments are conducted on different products. The validity of ISS is verified by comparing the optimization effects of ISS and nondominated sorting genetic algorithm (NSGA-II).

scholarly journals Optimal Location and Sizing of DGs in DC Networks Using a Hybrid Methodology Based on the PPBIL Algorithm and the VSA

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1913
Author(s):  
Luis Fernando Grisales-Noreña ◽  
Oscar Danilo Montoya ◽  
Ricardo Alberto Hincapié-Isaza ◽  
Mauricio Granada Echeverri ◽  
Alberto-Jesus Perea-Moreno
Keyword(s):  
Location Problem ◽  
Search Algorithm ◽  
Optimization Method ◽  
Population Based ◽  
Power Losses ◽  
Test Systems ◽  
Processing Times ◽  
Distributed Generators ◽  
Parallel Version

In this paper, we propose a master–slave methodology to address the problem of optimal integration (location and sizing) of Distributed Generators (DGs) in Direct Current (DC) networks. This proposed methodology employs a parallel version of the Population-Based Incremental Learning (PPBIL) optimization method in the master stage to solve the location problem and the Vortex Search Algorithm (VSA) in the slave stage to solve the sizing problem. In addition, it uses the reduction of power losses as the objective function, considering all the constraints associated with the technical conditions specific to DGs and DC networks. To validate its effectiveness and robustness, we use as comparison methods, different solution methodologies that have been reported in the specialized literature, as well as two test systems (the 21 and 69-bus test systems). All simulations were performed in MATLAB. According to the results, the proposed hybrid (PPBIL–VSA) methodology provides the best trade-off between quality of the solution and processing times and exhibits an adequate repeatability every time it is executed.

scholarly journals Multiple Hungarian Method for k-Assignment Problem

Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 2050
Author(s):  
Boštjan Gabrovšek ◽  
Tina Novak ◽  
Janez Povh ◽  
Darja Rupnik Poklukar ◽  
Janez Žerovnik
Keyword(s):  
Relative Error ◽  
Assignment Problem ◽  
Search Algorithm ◽  
Computation Time ◽  
Average Relative Error ◽  
Matching Problem ◽  
Solution Quality ◽  
Optimum Algorithm ◽  
Optimal Values

The k-assignment problem (or, the k-matching problem) on k-partite graphs is an NP-hard problem for k≥3. In this paper we introduce five new heuristics. Two algorithms, Bm and Cm, arise as natural improvements of Algorithm Am from (He et al., in: Graph Algorithms And Applications 2, World Scientific, 2004). The other three algorithms, Dm, Em, and Fm, incorporate randomization. Algorithm Dm can be considered as a greedy version of Bm, whereas Em and Fm are versions of local search algorithm, specialized for the k-matching problem. The algorithms are implemented in Python and are run on three datasets. On the datasets available, all the algorithms clearly outperform Algorithm Am in terms of solution quality. On the first dataset with known optimal values the average relative error ranges from 1.47% over optimum (algorithm Am) to 0.08% over optimum (algorithm Em). On the second dataset with known optimal values the average relative error ranges from 4.41% over optimum (algorithm Am) to 0.45% over optimum (algorithm Fm). Better quality of solutions demands higher computation times, thus the new algorithms provide a good compromise between quality of solutions and computation time.

OS CAMINHOS DAS ÁGUAS NO MUNICÍPIO DE CARIRÉ, CEARÁ, BRASIL

2019 ◽  
Vol 21 (2) ◽  
pp. 564-580
Author(s):  
Eloiza Rocha Queiroz ◽  
José Falcão Sobrinho
Keyword(s):  
Water Resources ◽  
Potable Water ◽  
Field Trips ◽  
Central Theme ◽  
Northeast Region ◽  
Brazilian Semiarid ◽  
Long Time ◽  
Short Rains ◽  
Two Stages

A região Nordeste do Brasil vem sendo alvo de medidas do Estado a mais de um século, na tentativa de solucionar o problema da falta de água em época de secas. O Estado do Ceará, por sua vez, apresenta boa parte de seu território inserido no semiárido brasileiro, uma região caracterizada pelo clima seco, com poucas chuvas e elevada evapotranspiração. A problemática da água existe há bastante tempo, principalmente o acesso em quantidade e qualidade suficientes para atender a população. O presente trabalho tem como tema central a questão dos recursos hídricos, com enfoque no abastecimento humano do município de Cariré, localizado na região noroeste do Ceará. Nosso objetivo consiste em apresentar um panorama de como atualmente a população carireense tem acesso à água potável. A metodologia adotada constitui-se em duas etapas: na primeira, realizamos levantamento de material bibliográfico e a segunda diz respeito a parte prática realizada em saídas a campo. Segundo a ONU, a água é um bem comum e que deve ser de acesso a todos, é um direito humano. Nesta perspectiva, o gerenciamento adequado dos recursos hídricos é essencial para a manutenção da qualidade de vida. Palavras-chave: Recursos Hídricos; Abastecimento Humano; Cariré-Ce. ABSTRACTThe pnortheast region from Brazil has been subject of measures for more than a century in attempts to solve the problems lack of water in dry season. The state of Ceará has a good part of its territorial inserted in Brazilian semiarid, a region characterized by dry climate, short rains and high evapotranspiration. The water issue has existed for a long time, mainly in a sufficient access of quantity and quality to serve the population. Then, this article has as a central theme the water resources focusing on water supply of the Cariré localized at Northeast region from Ceará. Therefore the purpose of the paper is to present a study about how the Carire’s population has had access to potable water currently. The methodology adopted to this research consists of two stages: Firstly it was carried out a survey of bibliographical material and secondly it concerned the practical part carried out in the field trips. In accordance to United nations, water is a commom good and it has to be available to everyone, it is a human rights. In that sense, the proper management of water resources is essential to keep the quality of life.Key-words: Human supply; Water resources; Cariré – Ce. RÉSUMÉLa région du nord-est du Brésil est la cible de mesures prises par l’État depuis plus d’un siècle pour tenter de résoudre le problème de la pénurie d’eau en saison sèche. L’État du Ceará, en revanche, présente une bonne partie de son territoire inséré dans le semi-aride brésilien, région caractérisée par un climat sec, avec peu de pluies et une forte évapotranspiration. Le problème de l'eau existe depuis longtemps, principalement l'accès en quantité et qualité suffisantes pour satisfaire la population. Le travail actuel a pour thème central la question des ressources en eau, en mettant l'accent sur l'approvisionnement humain de la municipalité de Cariré, située dans la région nord-ouest du Ceará. Notre objectif est de présenter un aperçu de la façon dont la population carioca a actuellement accès à l’eau potable. La méthodologie adoptée comporte deux étapes: dans le premier, nous procédons à une enquête sur le matériel bibliographique et le second à la partie pratique réalisée lors des visites sur le terrain. Selon l'ONU, l'eau est un bien commun et doit être accessible à tous, c'est un droit humain. Dans cette perspective, la gestion adéquate des ressources en eau est essentielle au maintien de la qualité de la vie.Mots-clés: Ressources en eau; Approvisionnement humain; Cariré-Ce.

scholarly journals A Modified Niching Crow Search Approach to Well Placement Optimization

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 857
Author(s):  
Jahedul Islam ◽  
Md Shokor A. Rahaman ◽  
Pandian M. Vasant ◽  
Berihun Mamo Negash ◽  
Ahshanul Hoqe ◽  
...  
Keyword(s):  
Optimization Problem ◽  
Search Algorithm ◽  
Gravitational Search Algorithm ◽  
Multimodal Optimization ◽  
Test Functions ◽  
Well Placement ◽  
Suggested Approach ◽  
Placement Optimization ◽  
Well Placement Optimization ◽  
Search Approach

Well placement optimization is considered a non-convex and highly multimodal optimization problem. In this article, a modified crow search algorithm is proposed to tackle the well placement optimization problem. This article proposes modifications based on local search and niching techniques in the crow search algorithm (CSA). At first, the suggested approach is verified by experimenting with the benchmark functions. For test functions, the results of the proposed approach demonstrated a higher convergence rate and a better solution. Again, the performance of the proposed technique is evaluated with well placement optimization problem and compared with particle swarm optimization (PSO), the Gravitational Search Algorithm (GSA), and the Crow search algorithm (CSA). The outcomes of the study revealed that the niching crow search algorithm is the most efficient and effective compared to the other techniques.

scholarly journals Multi-Resolution SPH Simulation of a Laser Powder Bed Fusion Additive Manufacturing Process

2021 ◽  
Vol 11 (7) ◽  
pp. 2962
Author(s):  
Mohamadreza Afrasiabi ◽  
Christof Lüthi ◽  
Markus Bambach ◽  
Konrad Wegener
Keyword(s):  
Search Algorithm ◽  
Computational Effort ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Neighbor Search ◽  
Particle Hydrodynamics ◽  
Sph Simulation ◽  
Particle Refinement ◽  
Search Approach

This paper presents an efficient mesoscale simulation of a Laser Powder Bed Fusion (LPBF) process using the Smoothed Particle Hydrodynamics (SPH) method. The efficiency lies in reducing the computational effort via spatial adaptivity, for which a dynamic particle refinement pattern with an optimized neighbor-search algorithm is used. The melt pool dynamics is modeled by resolving the thermal, mechanical, and material fields in a single laser track application. After validating the solver by two benchmark tests where analytical and experimental data are available, we simulate a single-track LPBF process by adopting SPH in multi resolutions. The LPBF simulation results show that the proposed adaptive refinement with and without an optimized neighbor-search approach saves almost 50% and 35% of the SPH calculation time, respectively. This achievement enables several opportunities for parametric studies and running high-resolution models with less computational effort.

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