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Seminarier i Optimeringslära

Dessa seminarier är organiserade av avdelningen för Optimeringslära.
För mer information, kontakta seminariekoordinator Oleg Burdakov.

 

Aktuella seminarier

Torsdag 30 november 2017, Jessika Boberg, Linköpings universitet

Examensarbete i matematik på kandidatnivå.

Talare: Jessika Boberg, Linköpings universitet

Titel: A comparison of sequencing formulations in a constraint generation procedure for avionics scheduling

Tid och plats: Torsdag 30 november 2017, Hopningspunkten, kl. 10:15

Sammanfattning: This thesis compares different mixed integer programming (MIP) formulations for sequencing of tasks in the context of avionics scheduling. Sequencing is a key concern in many discrete optimisation problems, and there are numerous ways of accomplishing sequencing with different MIP formulations.

A scheduling tool for avionic systems has previously been developed in a collaboration between Saab and Linköping University. This tool includes a MIP formulation of the scheduling problem where one of the model components has the purpose to sequence tasks. In this thesis, this sequencing component is replaced with other MIP formulations in order to study whether the computational performance of the scheduling tool can be improved.

Different scheduling instances and objective functions have been used when performing the tests aiming to evaluate the performances, with the computational times of the entire avionic scheduling model determining the success of the different MIP formulations for sequencing. The results show that the choice of MIP formulation makes a considerable impact on the computational performance and that a significant improvement can be achieved by choosing the most suitable one. 


Sat Sep 30 08:00:00 CEST 2017


Torsdag 14 december 2017, Andreas Westerlund, Jeppesen Systems AB, Göteborg

Talare: Andreas Westerlund, Jeppesen Systems AB, Göteborg

Titel: Column generation for airline crew rostering: practical considerations in a production system

Tid och plats: Torsdag 14 december 2017, Hopningspunkten, 10:15

Sammanfattning: Jeppesen's crew rostering optimizer is today used by around 40 airlines to produce monthly schedules for their flying crew. The optimizer produces monthly schedules for problem instances with above 20k crew-members and 100k activities. A key ingredient within the optimizer is our column generation framework. In this presentation, some of the main challenges within that framework will be described.


Sat Oct 14 10:53:00 CEST 2017



Sidansvarig: karin.johansson@liu.se
Senast uppdaterad: Mon Nov 20 15:52:36 CET 2017