Uma heurística de busca tabu simples para o problema de carregamento de paletes do produtor

Abstract

ResumoO problema de carregamento de paletes do produtor consiste em arranjar, ortogonalmente e sem sobreposição, o máximo número de caixas de dimensões (l,w) ou (w,l), sobre um palete retangular de dimensões (L,W). Este problema vem sendo tratado com sucesso por heurísticas de blocos, onde são gerados padrões de carregamento compostos por um ou mais blocos, cujas peças possuem a mesma orientação. Uma característica desses métodos é que os padrões gerados estão limitados aos chamados padrões não-guilhotinados de primeira ordem. Neste trabalho é proposta uma abordagem baseada na incorporação de busca tabu simples (sem estruturas de memória de longo prazo) em heurísticas de bloco. Partindo-se de uma solução inicial, são realizados movimentos de aumento de blocos, que resultam na diminuição, eliminação e criação de outros blocos. Resultados computacionais indicam que esta abordagem é capaz de gerar padrões ótimos de ordem superior em problemas de difícil resolução para outros métodos da literatura.Palavras-chave: problema de carregamento de paletes do produtor; problemas de corte e empacotamento; busca tabu simples. AbstractThe manufacturer's pallet loading problem consists in arranging, orthogonally and without overlapping, the maximum number of boxes with dimensions (l,w) or (w,l) onto a rectangular pallet with dimensions (L,W). This problem has been handled successfully by block heuristics, which generate loading patterns composed by one or more blocks where the pieces have the same orientation. A feature of such methods is that the patterns are limited to the so called 1 st order non-guillotine patterns. In this work we propose an approach based on the incorporation of simple tabu search (without longer term memory structures) in block heuristics. Starting from an initial pattern, the algorithm performs moves that increase the size of selected blocks in the current pattern; as a result, other blocks are decreased, eliminated or created. Computational results indicate that the approach is capable of generating superior order optimal patterns for difficult instances reported in the literature.

Design of a Hyperheuristic for Production Scheduling in Job Shop Environments

“…As previous affirmations, genetic algorithms, algorithms based on ant colonies, algorithms based on intelligent particles, expert systems, neuron nets, diffused logic, heuristics, taboo search and its variants; are different artificial intelligence techniques [29].…”

“…One of the best solutions is to reinforce it, while the quantity of the existing pheromone in the other arches will be penalized by means of the vaporization process. In some cases, especially when β = 0, or when it presents a value close to 0, the solution to the problems depends only on the pheromone traces (as is deduced from equation (1)) producing a stagnation of the problem in the local optimal [29,39].…”

Improved layout structure with complexity measures for the Manufacturer’s Pallet Loading Problem (MPLP] using a Block approach

“…We believe that testing against a wide range of datasets proves the validity of the proposed model in this paper. Table 2 represents the instances, the pallet dimensions X max and Y max the individual box dimension α and β, the objective value obtained from the published papers z, the results obtained from the Block approach Boxes and finally where the instances have been tested & Morabito, 1995, Bhattacharya et al, 1998Dowsland, 1984;Martins & Dell, 2008;Morabito & Morales, 1998;Pureza & Morabito, 2003;Wu & Ting, 2007 Morabito, 1995;Bhattacharya et al, 1998;Wu & Ting, 2007;Young-Gun & Kang, 2001;Arenales & Morabito, 1995;Bhattacharya et al, 1998;Dowsland, 1984;Wu & Ting, 2007;Young-Gun & Kang, 2001 Amaral & Wright, 2001;Bhattacharya et al, 1998;Martins & Dell, 2008;Morabito & Morales, 1998;Neliβen, 1995;Pureza & Morabito, 2003, 2006Wu & Ting, 2007;Young-Gun & Kang, 2001 13 57 44 12 5 41 41 Martins & Dell, 2008;Morabito & Morales, 1998;Neliβen, 1995;Pureza & Morabito, 2003, 2006Scheithauer & Terno, 1996a;Wu & Ting, 2007;Young-Gun & Kang, 2001 14 40 33 7 4 46 46 Bhattacharya et al, 1998;…”