2009
Autores
Amaral, A; Araujo, M;
Publicação
SHO2009: INTERNATIONAL SYMPOSIUM ON OCCUPATIONAL SAFETY AND HYGIENE
Abstract
2008
Autores
Parreno, F; Alvarez Valdes, R; Tamarit, JM; Oliveira, JF;
Publicação
INFORMS JOURNAL ON COMPUTING
Abstract
In this paper, a greedy randomized adaptive search procedure (GRASP) for the container loading problem is presented. This approach is based on a constructive block heuristic that builds upon the concept of maximal space, a nondisjoint representation of the free space in a container. This new algorithm is extensively tested over the complete set of Bischoff and Ratcliff problems [Bischoff, E. E., M. S. W. Ratcliff. 1995. Issues in the development of approaches to container loading. Omega 23 377-390], ranging from weakly heterogeneous to strongly heterogeneous cargo, and outperforms all the known nonparallel approaches that, partially or completely, have used this set of test problems. When comparing against parallel algorithms, it is better on average but not for every class of problem. In terms of efficiency, this approach runs in much less computing time than that required by parallel methods. Thorough computational experiments concerning the evaluation of the impact of algorithm design choices and internal parameters on the overall efficiency of this new approach are also presented.
2008
Autores
Almada Lobo, B; Oliveira, JF; Carravilla, MA;
Publicação
COMPUTERS & OPERATIONS RESEARCH
Abstract
Gupta and Magnusson [The capacitated lot-sizing and scheduling problem with sequence-dependent setup costs and setup times. Computers and Operations Research 2005;32(4):727-47] develop a model for the single machine capacitated lot-sizing and scheduling problem (CLSP) with sequence dependent setup times and setup costs, incorporating all the usual features of setup carryovers. In this note we show that this model does not avoid disconnected subtours. A new set of constraints is added to the model to provide an exact formulation for this problem.
2008
Autores
Almada Lobo, B; Oliveira, JF; Carravilla, MA;
Publicação
INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS
Abstract
Inspired by a case study, this paper reports a successful application of VNS to the production planning and scheduling problem that arises in the glass container industry. This is a multi-facility production system, where each facility has a set of furnaces where the glass paste is produced in order to meet the demand, being afterwards distributed to a set of parallel molding machines. Since the neighborhoods used are not nested, they are not ordered by increasing sizes, but by means of a new empirical measure to assess the distance between any two solutions. Neighborhood sizes decrease significantly through-out the search thus suggesting the use of a scheme in which efficiency is placed. over effectiveness in a first step, and the opposite in a second step. We test this variant as well as other two with a real-world problem instance from our case study.
2008
Autores
Bennell, JA; Oliveira, JF;
Publicação
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH
Abstract
Cutting and packing problems involving irregular shapes is an important problem variant with a wide variety of industrial applications. Despite its relevance to industry, research publications are relatively low when compared to other cutting and packing problems. One explanation offered is the perceived difficulty and substantial time investment of developing a geometric tool box to assess computer generated solutions. In this paper we set out to provide a tutorial covering the core geometric methodologies currently employed by researchers in cutting and packing of irregular shapes. The paper is not designed to be an exhaustive survey of the literature but instead will draw on the literature to illustrate the theory and implementation of the approaches. We aim to provide a sufficiently instructive description to equip new and current researchers in the area to select the most appropriate methodology for their needs.
2008
Autores
Chituc, CM; Toscano, C; Azevedo, A;
Publicação
COMPUTERS IN INDUSTRY
Abstract
The development of information and communication technologies and turbulent market conditions have forced enterprises to adapt their way of undertaking business, from traditional practices to e-business. in this context, achieving seamless interoperability among heterogeneous organizations becomes a critical issue. This article has two main objectives: (1) to present a review of the most relevant approaches aiming at achieving seamless interoperability in a collaborative networked environment. In this sense, major interoperability issues (e.g., interoperability requirements, technologies) are discussed, and the most significant independent (e.g., ebXML) and industry-specific initiatives (e.g., RosettaNet, papiNet, TexWeave) are analyzed; (2) to introduce a recently developed two-layered operational infrastructure aiming at attaining seamless interoperability in the footwear industry (the up-stream segment), based on the requirements identified for this sector in a recent industry survey conducted at European level. Other relevant initiatives targeting this sector are also analyzed, emphasizing the innovative aspects and advantages of this approach.
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