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Publications

Publications by CEGI

2011

Heuristics for Two-Dimensional Bin-Packing Problems

Authors
Chan, TK; Alvelos, F; Silva, E; de Carvalho, JMV;

Publication
The Industrial Electronics Handbook - Five Volume Set

Abstract
[No abstract available]

2011

HEURISTICS WITH STOCHASTIC NEIGHBORHOOD STRUCTURES FOR TWO-DIMENSIONAL BIN PACKING AND CUTTING STOCK PROBLEMS

Authors
Chan, TM; Alvelos, F; Silva, E; Valerio De Carvalho, JMV;

Publication
ASIA-PACIFIC JOURNAL OF OPERATIONAL RESEARCH

Abstract
This paper proposes a heuristic with stochastic neighborhood structures (SNS) to solve two-stage and three-stage two-dimensional guillotine bin packing and cutting stock problems. A solution is represented as a sequence of items which are packed into existing or new stacks, shelves or bins according to previously defined criteria. Moreover, SNS comprises three random neighborhood structures based on modifying the current sequence of items. These are called cut-and-paste, split, and swap blocks and are applied one by one in a fixed order to try to improve the quality of the current solution. Both benchmark instances and real-world instances provided by furniture companies were utilized in the computational tests. Particularly, all benchmark instances are bin packing instances (i.e., the demand of each item type is small), and all real-world instances are classified into bin packing instances and cutting stock instances (i.e., the demand of each item type is large). The computational results obtained by the proposed method are compared with lower bounds and with the solutions obtained by a deterministic Variable Neighborhood Descent (VND) meta-heuristic. The SNS provide solutions within a small percentage of the optimal values, and generally make significant improvements in cutting stock instances and slight to moderate improvements in bin packing instances over the VND approach.

2011

Factory templates: A decision support framework for manufacturing processes management

Authors
Azevedo, A; Almeida, A; Caldas, A;

Publication
Proceedings of the 6th Iberian Conference on Information Systems and Technologies, CISTI 2011

Abstract
In order to develop the new industrial paradigm, it is necessary to explore a framework supported by planning and operational tools. Indeed, it becomes clear that more and more the next factories need to be increasingly more flexible, agile and knowledge-based in order to be able to adapt in real time to the continuously changing market demands, technology options and regulations, as well as accelerate the design process and optimise production. Therefore, in this paper a framework capable of supporting the factory planning will be presented based on predefined templates and product requirements. Furthermore, the Factory Templates will allow for process deployment, control and evaluation in real-time. © 2011 AISTI.

2010

A hybrid GRASP/VND algorithm for two- and three-dimensional bin packing

Authors
Parreno, F; Alvarez Valdes, R; Oliveira, JF; Tamarit, JM;

Publication
ANNALS OF OPERATIONS RESEARCH

Abstract
The three-dimensional bin packing problem consists of packing a set of boxes into the minimum number of bins. In this paper we propose a new GRASP algorithm for solving three-dimensional bin packing problems which can also be directly applied to the two-dimensional case. The constructive phase is based on a maximal-space heuristic developed for the container loading problem. In the improvement phase, several new moves are designed and combined in a VND structure. The resulting hybrid GRASP/VND algorithm is simple and quite fast and the extensive computational results on test instances from the literature show that the quality of the solutions is equal to or better than that obtained by the best existing heuristic procedures.

2010

Neighborhood structures for the container loading problem: a VNS implementation

Authors
Parreno, F; Alvarez Valdes, R; Oliveira, JF; Tamarit, JM;

Publication
JOURNAL OF HEURISTICS

Abstract
This paper presents a Variable Neighborhood Search (VNS) algorithm for the container loading problem. The algorithm combines a constructive procedure based on the concept of maximal-space, with five new movements defined directly on the physical layout of the packed boxes, which involve insertion and deletion strategies. The new algorithm is tested on the complete set of Bischoff and Ratcliff problems, ranging from weakly to strongly heterogeneous instances, and outperforms all the reported algorithms which have used those test instances.

2010

Multiple machine continuous setup lotsizing with sequence-dependent setups

Authors
Almada Lobo, B; Klabjan, D; Carravilla, MA; Oliveira, JF;

Publication
COMPUTATIONAL OPTIMIZATION AND APPLICATIONS

Abstract
We address the short-term production planning and scheduling problem coming from the glass container industry. A furnace melts the glass that is distributed to a set of parallel molding machines. Both furnace and machine idleness are not allowed. The resulting multi-machine multi-item continuous setup lotsizing problem with a common resource has sequence-dependent setup times and costs. Production losses are penalized in the objective function since we deal with a capital intensive industry. We present two mixed integer programming formulations for this problem, which are reduced to a network flow type problem. The two formulations are improved by adding valid inequalities that lead to good lower bounds. We rely on a Lagrangian decomposition based heuristic for generating good feasible solutions. We report computational experiments for randomly generated instances and for real-life data on the aforementioned problem, as well as on a discrete lotsizing and scheduling version.

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