N–Dimensional Orthogonal Tile Sizing Problem

AMS subject classification: 68Q22, 90C90

装配车间的多品种变批量的生产调度优化模型

针对装配车间调度问题,提出了综合考虑生产中物料配送能力,车间存储物料能力以及装配工艺序列问题的多品种变批次的优化调度方法。主要是分两步解决:首先考虑不同类型产品的装配加工的顺序优化问题;然后,根据生产约束建立各类型产品的分批问题。最后,实现计划调度衔接,并应用于生产。该方法对于实际装配生产具有很强的可操作性。

A linear optimization approach to the combined production planning model

Two fundamental processes usually arise in the production planning of many industries. The first one consists of deciding how many final products of each type have to be produced in each period of a planning horizon, the well-known lot sizing problem. The other process consists of cutting raw materials in stock in order to produce smaller parts used in the assembly of final products, the well-studied cutting stock problem. In this paper the decision variables of these two problems are dependent of each other in order to obtain a global optimum solution. Setups that are typically present in lot sizing problems are relaxed together with integer frequencies of cutting patterns in the cutting problem. Therefore, a large scale linear optimizations problem arises, which is exactly solved by a column generated technique. It is worth noting that this new combined problem still takes the trade-off between storage costs (for final products and the parts) and trim losses (in the cutting process). We present some sets of computational tests, analyzed over three different scenarios. These results show that, by combining the problems and using an exact method, it is possible to obtain significant gains when compared to the usual industrial practice, which solve them in sequence. (C) 2010 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

A linear optimization approach to the combined production planning model

Two fundamental processes usually arise in the production planning of many industries. The first one consists of deciding how many final products of each type have to be produced in each period of a planning horizon, the well-known lot sizing problem. The other process consists of cutting raw materials in stock in order to produce smaller parts used in the assembly of final products, the well-studied cutting stock problem. In this paper the decision variables of these two problems are dependent of each other in order to obtain a global optimum solution. Setups that are typically present in lot sizing problems are relaxed together with integer frequencies of cutting patterns in the cutting problem. Therefore, a large scale linear optimizations problem arises, which is exactly solved by a column generated technique. It is worth noting that this new combined problem still takes the trade-off between storage costs (for final products and the parts) and trim losses (in the cutting process). We present some sets of computational tests, analyzed over three different scenarios. These results show that, by combining the problems and using an exact method, it is possible to obtain significant gains when compared to the usual industrial practice, which solve them in sequence. (C) 2010 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

Genetic algorithm, MIP and improvement heuristic applied to the MLCLP with backlogging

The present paper solves the multi-level capacitated lot sizing problem with backlogging (MLCLSPB) combining a genetic algorithm with the solution of mixed-integer programming models and the improvement heuristic fix and optimize. This approach is evaluated over sets of benchmark instances and compared to methods from literature. Computational results indicate competitive results applying the proposed method when compared with other literature approaches. © 2013 IEEE.

Modelos matemáticos para o problema integrado de dimensionamento de lotes e corte de estoque undimensional

Pós-graduação em Matemática - IBILCE

Limitantes inferiores par ao problema de dimensionamento de lotes em máquinas paralelas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Reformulações e relaxação Lagrangiana para o problema de dimensionamento de lotes com várias plantas

Pós-graduação em Matemática - IBILCE

Formulações fortes para o problema integrado de dimensionamento e sequenciamento da produção

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modelagem do problema integrado de dimensionamento de lotes e corte de estoque em indústria moveleira

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Problema integrado de dimensionamento de lotes e corte de estoque na indústria moveleira

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Formulações fortes para o problema de dimensionamento de lotes com várias plantas

This paper considers the multi-plant lot sizing problem. Each item can be produced in any plant and it is possible to meet the demand of a particular plant with production from one (or several) other plants, in this case, incurs a transfer cost. The objective is todevelop strong formulations for this problem. Reformulations that based on the shortest path problem and facility location problem are investigated. Finally, some computational results are presented comparing all the proposed formulations.

Relaxação Lagrangiana Aplicada ao Problema de Dimensionamento de Lotes em Máquinas Paralelas: Limitantes Inferiores

This paper addresses the single stage lot-sizing problem in parallel machines. Each item can be produced on any machine, and incurs a setup time before to start the production. The objective of this paper is to obtain lower bounds of good quality for this problem. A solution method is developed based on a reformulation of the problem and the Lagrangian relaxation of a set of constraints. Some computational results are presented comparing the proposed method with a method from the literature and with a computational package.

Modelos Matemáticos e Métodos de Solução para Problemas de Dimensionamento de Lotes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modelos matemáticos para o problema integrado de dimensionamento de lotes e corte de estoque unidimensional

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)