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About

Hello!

I am a teacher at the Faculty of Economics, University of Porto, and a researcher at LIAAD, one of INESC TEC's  research groups.

My research mostly involves the development and application of (meta)heuristic procedures to combinatorial optimization problems, particularly scheduling problems. Currently, I am also learning data mining.

Interest
Topics
Details

Details

  • Name

    Jorge Valente
  • Cluster

    Computer Science
  • Role

    Research Coordinator
  • Since

    01st October 2012
Publications

2020

Minimizing total earliness and tardiness in a nowait flow shop

Authors
Schaller, J; Valente, JMS;

Publication
INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS

Abstract
This paper considers the problem of scheduling jobs in a no-wait flow shop with the objective of minimizing total earliness and tardiness. An exact branch-and-bound algorithm is developed for the problem. Several dispatching heuristics used previously for other environments and two new heuristics were tested under a variety of conditions. It was found that one of the new heuristics consistently performed well compared to the others. An insertion search improvement procedure with speed up methods based on the structure of the problem was proposed and was found to deliver much improved solutions in a reasonable amount of time.

2019

Heuristics for scheduling jobs in a permutation flow shop to minimize total earliness and tardiness with unforced idle time allowed

Authors
Schaller, J; Valente, JMS;

Publication
EXPERT SYSTEMS WITH APPLICATIONS

Abstract
This paper considers the problem of scheduling jobs in a permutation flow shop with the objective of minimizing total earliness and tardiness. Unforced idle time is considered in order to reduce the earliness of jobs. It is shown how unforced idle time can be inserted on the final machine. Several dispatching heuristics that have been used for the problem without unforced idle time were modified and tested. Several procedures were also developed that conduct a second pass to develop a sequence using dispatching rules. These procedures were also tested and were found to result in better solutions.

2019

Branch-and-bound algorithms for minimizing total earliness and tardiness in a two-machine permutation flow shop with unforced idle allowed

Authors
Schaller, J; Valente, J;

Publication
COMPUTERS & OPERATIONS RESEARCH

Abstract
The two-machine permutation flow shop scheduling problem with the objective of minimizing total earliness and tardiness is addressed. Unforced idle time can be used to complete jobs closer to their due dates. It is shown that unforced idle time only needs to be considered on the second machine. This result is then used to extend a lower bound and dominance conditions for the single-machine problem to the two-machine permutation flow shop problem. Two branch-and-bound algorithms are developed for the problem utilizing the lower bound and dominance conditions. The algorithms are tested using instances that represent a wide variety of conditions.

2018

Iterated-greedy-based algorithms with beam search initialization for the permutation flowshop to minimise total tardiness

Authors
Fernandez Viagas, V; Valente, JMS; Framinan, JM;

Publication
EXPERT SYSTEMS WITH APPLICATIONS

Abstract
The permutation flow shop scheduling problem is one of the most studied operations research related problems. Literally, hundreds of exact and approximate algorithms have been proposed to optimise several objective functions. In this paper we address the total tardiness criterion, which is aimed towards the satisfaction of customers in a make-to-order scenario. Although several approximate algorithms have been proposed for this problem in the literature, recent contributions for related problems suggest that there is room for improving the current available algorithms. Thus, our contribution is twofold: First, we propose a fast beam-search-based constructive heuristic that estimates the quality of partial sequences without a complete evaluation of their objective function. Second, using this constructive heuristic as initial solution, eight variations of an iterated-greedy-based algorithm are proposed. A comprehensive computational evaluation is performed to establish the efficiency of our proposals against the existing heuristics and metaheuristics for the problem.

2018

Efficient heuristics for minimizing weighted sum of squared tardiness on identical parallel machines

Authors
Schaller, J; Valente, JMS;

Publication
Computers and Industrial Engineering

Abstract
Scheduling jobs on a set of identical parallel machines using efficient heuristics when the objective is to minimize total weighted squared tardiness is considered. Two efficient heuristics and an improvement procedure are presented for the problem. These heuristics and other heuristics are tested using problem sets that represent a variety of conditions. The results show that one of the heuristics consistently performs better than the other heuristics tested. It is also shown how these heuristics can be incorporated into other procedures such as the existing Lagrangian relaxation procedure or meta-heuristics to obtain improved solutions for medium sized problems. © 2018 Elsevier Ltd

Supervised
thesis

2019

Heuristics for the Distributed Permutation Flowshop Scheduling Problem with the Weighted Tardiness Objective

Author
Maria Inês Ferraz Cerveira

Institution
UP-FEP

2018

Adaptive learning redemption rate prediction model

Author
Camila Helena Ölund Matos

Institution
UP-FEP

2018

Heuristics for the single machine weighted quadratic tardiness scheduling problem with unequal release date

Author
James Teddy Limousin Sambuchetti

Institution
UP-FEP

2017

Os Potenciais Hinterlands dos Portos Portugueses para Cargas Contentorizadas, Baseado nas Acessibilidades Rodoviárias.

Author
Pedro Vasco e Silva Cardoso

Institution
UP-FEP

2016

Metaheuristics for the Weighted Squared Tardiness Permutation Flowshop Scheduling Problem

Author
Andreia Fernandes da Silva

Institution
UP-FEP