Luiz Leduino de Salles Neto

Nonlinear cutting stock problem model to minimize the number of different patterns and objects

In this article we solve a nonlinear cutting stock problem which represents a cutting stock problem that considers the minimization of, both, the number of objects used and setup. We use a linearization of the nonlinear objective function to make possible the generation of good columns with the Gilmore and Gomory procedure. Each time a new column is added to the problem, we solve the original nonlinear problem by an Augmented Lagrangian method. This process is repeated until no more profitable columns is generated by Gilmore and Gomory technique. Finally, we apply a simple heuristic to obtain an integral solution for the original nonlinear integer problem.

A genetic symbiotic algorithm applied to the one-dimensional cutting stock problem

This work presents a genetic symbiotic algorithm to minimize the number of objects and the setup in a one-dimensional cutting stock problem. The algorithm implemented can generate combinations of ordered lengths of stock (the cutting pattern) and, at the same time, the frequency of the cutting patterns, through a symbiotic process between two distinct populations, solutions and cutting patterns. Working with two objectives in the fitness function and with a symbiotic relationship between the two populations, we obtained positive results when compared with other methods described in the literature.

Pareto clustering search applied for 3D container ship loading plan problem

Pareto Clustering Search (PCS) is a hybrid method to solve multi-objective problems.PCS detects promising areas and applies local search heuristics only in these areas.We apply the PCS to solve the 3D Container ship Loading Plan Problem (CLPP).The PCS provides better solutions for the CLPP than mono-objective methods.Decision maker chooses the solution that best meets their interests in a situation. The 3D Container ship Loading Plan Problem (CLPP) is an important problem that appears in seaport container terminal operations. This problem consists of determining how to organize the containers in a ship in order to minimize the number of movements necessary to load and unload the container ship and the instability of the ship in each port. The CLPP is well known to be NP-hard. In this paper, the hybrid method Pareto Clustering Search (PCS) is proposed to solve the CLPP and obtain a good approximation to the Pareto Front. The PCS aims to combine metaheuristics and local search heuristics, and the intensification is performed only in promising regions. Computational results considering instances available in the literature are presented to show that PCS provides better solutions for the CLPP than a mono-objective Simulated Annealing.

Application of Genetic Algorithm to Minimize the Number of Objects Processed and Setup in a One-Dimensional Cutting Stock Problem

This paper presents the application of the one new approach using Genetic Algorithm in solving One-Dimensional Cutting Stock Problems in order to minimize two objectives, usually conflicting, i.e., the number of processed objects and setup while simultaneously treating them as a single goal. The model problem, the objective function, the method denominated SingleGA10 and the steps used to solve the problem are also presented. The obtained results of the SingleGA10 are compared to the following methods: SHP, Kombi234, ANLCP300 and Symbio10, found in literature, verifying its capacity to find feasible and competitive solutions. The computational results show that the proposed method, which only uses a genetic algorithm to solve these two objectives inversely related, provides good results.

A GRASP METAHEURISTIC FOR THE ORDERED CUTTING STOCK PROBLEM

Este estudio presenta un nuevo modelo matematico y un procedimiento meta-heuristico de busqueda voraz adaptativa y aleatoria (GRASP, por sus siglas en ingles) para resolver el problema de stock de corte ordenado. Este problema ha sido introducido recientemente en la literatura. Es apropiado minimizar la materia prima usada por las industrias que manipulan inventarios reducidos de productos, tales como las industrias que usan la base justo a tiempo para su produccion. En tales casos, los modelos clasicos para resolver el problema de stock de corte ordenado son inutiles. Los resultados obtenidos, mediante experimentos computacionales para un conjunto de ejemplos aleatorios, demuestran que el metodo propuesto puede ser aplicado a industrias grandes que procesan cortes en sus lineas de produccion y no mantienen en stock sus productos.

Solving the 3D stowage planning problem integrated with the quay crane scheduling problem by representation by rules and genetic algorithm

Abstract The operational efficiency of a port depends on proper container movement planning, called “stowage planning”, especially because unloading and loading container ships demands time, and this has a cost. Thus, the optimization of operations through stages is important to avoid blockage activities. This paper proposes a framework for solving the 3D stowage planning (3D SP) problem for container ships integrated with the scheduling of quay cranes (SQC) problem. 3D SP and SQC problems are interrelated and combinatorial, justifying the applications of meta-heuristics like a genetic algorithm combined with simulation and representation by rules. The robustness of the developed approach is attested in problems with 30 ports, 1500 TEUs ship or 15 ports and 22,000 TEUs ship and two quay cranes. These studies showed that the addition of the SQC problem leads to a 45.82% increase in load/unload time for the 3D SP problem solution, on average. This could help the charterer to avoid paying charges to the shipowner due to its an extra unplanned use of the vessel. Additionally, the developed methodology also helps to explain a long term phenomena of continuous increasing in container ship capacity since 1950s.

O problema da distância geométrica intervalar via otimização global

Neste trabalho apresentamos uma nova modelagem matematica, via otimizacao global e funccao intervalar, para o problema da distância geometrica intervalar (PDGi). O objetivo do PDGi, no contexto da estrutura de proteinas, consiste em encontrar uma realizacao em R3 de um grafo G=(V,E), onde as distancias entre os vertices sao dadas por intervalos, em conformidade com as medidas experimentais obtidas pela Ressonância Magnetica Nuclear. Em particular, esse trabalho aborda o problema de encontrar a posicao de cada atomo (vertice) de uma proteina, dado as distâncias intervalares desse vertice a tres vertices anteriores. Os resultados demonstram que a abordagem e promissora.

Método Heurístico para problemas de Otimização sob Incerteza, baseado em Simulação de Monte Carlo

Este trabalho trata o problema de otimizacao com parâmetros incertos, pertencentes a um conjunto conhecido previamente, tal que as variaveis devem ser determinadas antes de se conhecer o real valor dos parâmetros. E proposto um metodo heuristico que busca, atraves da combinacao das informacoes acumuladas ao resolver uma colecao de problemas de otimizacao que compartilham da estrutura do problema inicial, encontrar uma solucao -robusta, nao necessitando de reformulacoes do problema inicial. Os resultados computacionais realizados com dois estudos de caso, um problema de programacao linear e um de programacao nao linear, mostram um bom desempenho do metodo heuristico, sendo necessaria maior investigacao em estudos futuros.

A Linear Integer Mathematical Model for Stowage Planning with Ship Stability

The contribution of this paper is the formulation of a new mathematical formulation which brings a linear bi- objective function to reduce total number of container movements and also improve container ship stability issues. Since each movement costs at most, depending on port, US

Otimização dos custos de descarregamento de navios no Porto de Tubarão

200, then minimization of number of movements is related with economic aspects. In addition, concerns about typical ship stability measures, like metacentric height and angle list, has been considered in the proposed approach and help to prevent ship capsize. The results attests the validity of proposed model and shows the impact of each objective function in container ship arrangement through ports.