please discard my morning email notice (I made a mistake in the date of
the next seminar) and use the one below.
Kind regards
Zdenek
Dear scheduling researcher,
We are delighted to announce the talk given by Rubén Ruiz (UP de València).
The title is "State-of-the-art flowshop scheduling heuristics: Dos and
Don'ts".
The seminar will take place on Zoom on Wednesday, December 22 at 14:00 UTC.
Join Zoom Meeting
https://cesnet.zoom.us/j/91381308994?pwd=bFgzTFR1ZzlNNHpybTc5YTlTTHRxQT09
<https://cesnet.zoom.us/j/91381308994?pwd=bFgzTFR1ZzlNNHpybTc5YTlTTHRxQT09>
Meeting ID: 913 8130 8994
Passcode: 212305
You can follow the seminar online or offline on our Youtube channel as well:
https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A
The abstract follows.
Many scheduling problems are simply too hard to be solved exactly,
especially for instances of medium or large size or when realistic
constraints are present. As a result, the literature on heuristics and
metaheuristics for scheduling is extensive. More often than not,
metaheuristics are capable of generating solutions close to optimality
or to tight lower bounds for instances of realistic size in a matter of
minutes. Metaheuristics have been refined over the years and there are
literally hundreds of papers published every year with applications to
most domains in many different journals. Most regrettably, some of these
methods are complex in the sense that they have many parameters that
affect performance and hence need careful calibration. Furthermore, many
times published results are hard to reproduce due to specific speed-ups
being used or complicated software constructs. These complex methods are
difficult to transfer to industries in the case of scheduling problems.
Another important concern is the recently recognized "tsunami" of novel
metaheuristics that mimic the most bizarre natural or human processes,
as for example intelligent water drops, harmony search, firefly
algorithms and the like. See K. Sörensen "Metaheuristics—The Metaphor
exposed" (2015), ITOR 22(1):3-18. In this presentation, we briefly
review different flowshop problems and variants. From the basic flowshop
problem with makespan minimization to other objectives like flowtime
minimization, flowshops with sequence-dependent setup times, no-idle
flowshops, all the way up to complex hybrid flexible flowline problems.
We will show how simple Iterated Greedy (IG) algorithms often outperform
much more complex approaches. IG methods are inherently simple with very
few parameters. They are easy to code and results are easy to reproduce.
We will show that for all tested problems so far they show
state-of-the-art performance despite their simplicity. As a result, we
will defend the choice of simpler, yet good performing approaches over
complicated metaphor-based algorithms.
The next talk in our series will be given by
Christian Artigues (LAAS-CNRS
<https://homepages.laas.fr/artigues/drupal/node/11> Toulouse)| January
19, 2022| Mixed-integer linear programming for resource-constrained
scheduling
For more details, please visit https://schedulingseminar.com/
With kind regards
Zdenek, Mike and Guohua
--
Zdenek Hanzalek
Industrial Informatics Department,
Czech Institute of Informatics, Robotics and Cybernetics,
Czech Technical University in Prague,
Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic
https://rtime.ciirc.cvut.cz/~hanzalek/
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