18 Int. J. Computational Intelligence Studies, Vol. 9, Nos. 1/2, 2020
Solving flexible job-shop problem with sequence
dependent setup time and learning effects using
an adaptive genetic algorithm
Ameni Azzouz*, Meriem Ennigrou and
Lamjed Ben Said
Institut Sup´ erieur de Gestion,
SMART Lab,
Universit´ e de Tunis, Tunisia
Email: ameni.azzouz@isg.rnu.tn
Email: meriem.ennigrou@enit.rnu.tn
Email: Lamjed.bensaid@isg.rnu.tn
*Corresponding author
Abstract: For the most schedulling problems studied in literature, job
processing times are assumed to be known and constant over time. However,
this assumption is not appropriate for many realistic situations where the
employees and the machines execute the same task in a repetitive manner.
They learn how to perform more efficiently. As a result, the processing
time of a given job is shorter if it is scheduled later, rather than earlier
in the sequence. In this paper, we consider the flexible job-shop problem
(FJSP) with two kinds of constraint, namely, the sequence-dependent setup
times (SDST) and the learning effects. Makespan is specified as the objective
function to be minimised. To solve this problem, an adaptive genetic
algorithm (AGA) is proposed. Our algorithm uses an adaptive strategy based
on: 1) the current specificity of the search space; 2) the preceding results of
already used operators; 3) their associated parameter settings. We adopt this
strategy in order to maintain the balance between exploration and exploitation.
Experimental studies are presented to assess and validate the benefit of the
incorporation of the learning process to the SDST-FJSP over the original
problem.
Keywords: schedulling problem; genetic algorithm; adaptive strategy;
learning effects.
Reference to this paper should be made as follows: Azzouz, A., Ennigrou, M.
and Ben Said, L. (2020) ‘Solving flexible job-shop problem with sequence
dependent setup time and learning effects using an adaptive genetic
algorithm’, Int. J. Computational Intelligence Studies, Vol. 9, Nos. 1/2,
pp.18–32.
Biographical notes: Ameni Azzouz received her BSc and MS from the
University of Mannouba, Tunis, Tunisia, in 2010 and 2013, respectively and
her PhD from the University of Tunis in 2017, all in Computer Science.
She is currently a research member of SMART Lab. with University of Tunis,
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