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Sobre
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Sobre

A minha área de investigação principal é a Investigação Operacional e os Métodos Quantitativos aplicados à Gestão. Neste âmbito, a área de aplicação principal são os problema de Cortes e Empacotamentos enquanto, do ponto de vista das técnicas, a minha investigação está centrada na utilização e desenvolvimento de abordagens baseadas em metaheurísticas.

Os problemas de Cortes e Empacotamentos são, na sua maioria, problemas de optimização combinatória NP-difíceis e ocorrem em vários contextos práticos sempre que peças grandes de matéria-prima tenham que ser cortadas em peças mais pequenas ou, alternativamente, itens pequenos tenham que ser empacotados dentro de um contentor maior, de forma a que o desperdício, de matéria-prima ou espaço, seja minimizado. Estes problemas incluem difíceis restrições geométricas na sua camada de optimização. Também trabalhei em problemas de determinação de rotas de veículos. A minha investigação em problemas de sequenciamento de determinação de lotes em contextos industriais deriva fundamentalmente do meu trabalho com metaheurísticas.

Mais recentemente tenho trabalhado na utilização dos métodos quantitativos providenciados pela Investigação Operacional no apoio à decisão na gestão de instituições do ensino superior, o que inclui a avaliação institucional e de recursos humanos, "benchmarking", sustentabilidade e modelos de avaliação de carga e desempenho.

Tópicos
de interesse
Detalhes

Detalhes

010
Publicações

2020

Tactical sales and operations planning: A holistic framework and a literature review of decision-making models

Autores
Pereira, DF; Oliveira, JF; Carravilla, MA;

Publicação
International Journal of Production Economics

Abstract
Tactical Sales and Operations Planning (S&OP) has emerged as an extension of the aggregate production planning, integrating mid-term decisions from procurement, production, distribution, and sales in a single plan. Despite the growing interest in the subject, past synthesizing research has focused more on the qualitative and procedural aspects of the topic rather than on modeling approaches to the problem. This paper conducts a review of the existing decision-making, i.e., optimization, models supporting S&OP. A holistic framework comprising the decisions involved in this planning activity is presented. The reviewed literature is arranged within the framework and grouped around different streams of literature which have been extending the aggregate production planning. Afterwards, the papers are classified according to the modeling approaches employed by past researchers. Finally, based on the characterization of the level of integration of different business functions provided by existing models, the review demonstrates that there are no synthesizing models characterizing the overall S&OP problem and that, even in the more comprehensive approaches, there is potential to include additional decisions that would be the basis for more sophisticated and proactive S&OP programs. We do expect this paper contributes to set the ground for more oriented and structured research in the field. © 2020 Elsevier B.V.

2020

Irregular packing problems: A review of mathematical models

Autores
Leao, AAS; Toledo, FMB; Oliveira, JF; Carravilla, MA; Alvarez Valdes, R;

Publicação
European Journal of Operational Research

Abstract
Irregular packing problems (also known as nesting problems)belong to the more general class of cutting and packing problems and consist of allocating a set of irregular and regular pieces to larger rectangular or irregular containers, while minimizing the waste of material or space. These problems combine the combinatorial hardness of cutting and packing problems with the computational difficulty of enforcing the geometric non-overlap and containment constraints. Unsurprisingly, nesting problems have been addressed, both in the scientific literature and in real-world applications, by means of heuristic and metaheuristic techniques. However, more recently a variety of mathematical models has been proposed for nesting problems. These models can be used either to provide optimal solutions for nesting problems or as the basis of heuristic approaches based on them (e.g. matheuristics). In both cases, better solutions are sought, with the natural economic and environmental positive impact. Different modeling options are proposed in the literature. We review these mathematical models under a common notation framework, allowing differences and similarities among them to be highlighted. Some insights on weaknesses and strengths are also provided. By building this structured review of mathematical models for nesting problems, research opportunities in the field are proposed. © 2019 Elsevier B.V.

2020

Models for the two-dimensional level strip packing problem - a review and a computational evaluation

Autores
Bezerra, VMR; Leao, AAS; Oliveira, JF; Santos, MO;

Publicação
JOURNAL OF THE OPERATIONAL RESEARCH SOCIETY

Abstract
The two-dimensional level strip packing problem has received little attention from the scientific community. To the best of our knowledge, the most competitive model is the one proposed in 2004 by Lodi et al., where the items are packed by levels. In 2015, an arc flow model addressing the two-dimensional level strip cutting problem was proposed by Mrad. The literature presents some mathematical models, despite not addressing specifically the two-dimensional level strip packing problem, they are efficient and can be adapted to the problem. In this paper, we adapt two mixed integer linear programming models from the literature, rewrite the Mrad's model for the strip packing problem and add well-known valid inequalities to the model proposed by Lodi et al. Computational results were performed on instances from the literature and show that the model put forward by Lodi et al. with valid inequalities outperforms the remaining models with respect to the number of optimal solutions found.

2020

Integrating irregular strip packing and cutting path determination problems: A discrete exact approach

Autores
Oliveira, LT; Silva, EF; Oliveira, JF; Toledo, FMB;

Publicação
Computers and Industrial Engineering

Abstract
The irregular strip packing problem arises in a wide variety of industrial sectors, from garment and footwear to the metal industry, and has a substantial impact in raw-material waste minimization. The goal of this problem is to find a layout for a large object to be cut into smaller pieces. What differentiates this problem from all the other cutting and packing problems, and is its primary source of complexity, is the irregular (non-rectangular) shape of the small pieces. However, in practical applications, after a layout has been determined, a second problem arises: finding the path that the cutting tool has to follow to actually cut the pieces, as previously planned. This second problem is known as the cutting path determination problem. Although the solution of the first problem strongly influences the resolution of the second one, only a few studies are dealing with cutting/packing and cutting path determination together, and, to the best of the authors’ knowledge, none of them considers the irregular strip packing problem. In this paper, we propose the first mathematical programming model that integrates the irregular strip packing and the cutting path determination problems. Computational experiments were run to show the correctness of the proposed model and the advantage of tackling the two problems together. Two variants of the cutting path determination problem were considered, the fixed vertex and the free cut models. The strengths and drawbacks of these two variants are also established through computational experiments. Overall, the computational results show that the integration of these problems is advantageous, even if only small instances could be solved to optimality, given that solving to optimality the integrated is at least as difficult as solving each one of the other problems individually. As future research, it should be highlighted that the proposed integrated model is a solid basis for the development of matheuristics aiming at tackling real-world size problems. © 2020 Elsevier Ltd

2019

A co-evolutionary matheuristic for the car rental capacity-pricing stochastic problem

Autores
Oliveira, BB; Carravilla, MA; Oliveira, JF; Costa, AM;

Publicação
European Journal of Operational Research

Abstract

Teses
supervisionadas

2019

The Social Impact of the use of Cyber-Physical Systems in Manufacturing

Autor
Diogo Manuel Rebelo de Azevedo Seabra Pimenta

Instituição
UP-FEUP

2019

A Simulation-Optimization Model to Determine Fashion Delivery Patterns

Autor
Daniela Timóteo Martins de Pinho

Instituição
UP-FEUP

2019

An Optimization Approach to Production Planning with Scheduling Dependent Capacity and Resource Allocation

Autor
Rafael Leonardo Ribeiro de Carvalho

Instituição
UP-FEUP

2019

Otimização do parqueamento de aeronaves em hangares de manutenção

Autor
Bruno Manuel João Estevinho

Instituição
UP-FEUP

2018

Fleet and revenue management in car rental: quantitative approaches for optimization under uncertainty

Autor
Maria Beatriz Brito Oliveira

Instituição
UP-FEUP