ORBEL 32

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Schedule

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Thursday, February 1
08:30-09:15Welcome
09:15-09:30Opening session
09:30-10:30Plenary session - Dominique Feillet (Chair: Yasemin Arda)
10:30-11:00Coffee break
11:00-12:20Parallel sessions
  Routing Problems
Chair: Pieter Vansteenwegen
Room: 138
Emergency operations scheduling
Chair: El-Houssaine Aghezzaf
Room: 130
Algorithm design
Chair: Gerrit Janssens
Room: 126
Multiple Objectives
Chair: Filip Van Utterbeeck
Room: 120
12:20-13:30Lunch
12:25-13:25ORBEL board meeting
13:30-14:50Parallel sessions
  Integrated logistics
Chair: Kris Braekers
Room: 138
Person transportation
Chair: Célia Paquay
Room: 130
Continuous models
Chair: Nicolas Gillis
Room: 126
Integer programming
Chair: Bernard Fortz
Room: 120
14:50-15:20Coffee break
15:20-16:20Parallel sessions
  Material handling and warehousing 1
Chair: Greet Vanden Berghe
Room: 138
Operations management
Chair: Roel Leus
Room: 130
Matrix factorization
Chair: Pierre Kunsch
Room: 126
 
16:30-17:10Parallel sessions
  Material handling and warehousing 2
Chair: Katrien Ramaekers
Room: 138
Routing and local search
Chair: An Caris
Room: 130
Traffic management
Chair: Joris Walraevens
Room: 126
Pharmaceutical supply chains
Chair: Bart Smeulders
Room: 120
17:15-18:15ORBEL general assembly
18:30-...Conference dinner

Friday, February 2
09:30-10:30Plenary session - Martin Savelsbergh (Chair: Yves Crama)
10:30-10:50Coffee break
10:50-12:10Parallel sessions
  Optimization in health care
Chair: Jeroen Beliën
Room: 138
Network design
Chair: Jean-Sébastien Tancrez
Room: 130
Local search methodology
Chair: Patrick De Causmaecker
Room: 126
ORBEL Award
Chair: Frits Spieksma
Room: 120
12:10-13:00Lunch
13:00-14:00Parallel sessions
  Production and inventory management
Chair: Tony Wauters
Room: 138
Logistics 4.0
Chair: Thierry Pironet
Room: 130
Data clustering
Chair: Yves De Smet
Room: 126
Collective decision making
Chair: Bernard De Baets
Room: 120
14:10-15:10Parallel sessions
  Sport scheduling
Chair: Dries Goossens
Room: 138
Discrete choice modeling
Chair: Virginie Lurkin
Room: 130
Data classification
Chair: Ashwin Ittoo
Room: 126
 
15:10-15:30Coffee break
15:30- 16:30Plenary session - Michel Bierlaire (Chair: Michaël Schyns)
16:30- 16:45ORBEL award and closing session
16:45-18:00Closing cocktail

Thursday 11:00 - 12:20 Routing Problems
Room 138 - Chair: Pieter Vansteenwegen

Thursday 11:00 - 12:20 Emergency operations scheduling
Room 130 - Chair: El-Houssaine Aghezzaf

Thursday 11:00 - 12:20 Algorithm design
Room 126 - Chair: Gerrit Janssens

Thursday 11:00 - 12:20 Multiple Objectives
Room 120 - Chair: Filip Van Utterbeeck

Thursday 13:30 - 14:50 Integrated logistics
Room 138 - Chair: Kris Braekers

Thursday 13:30 - 14:50 Person transportation
Room 130 - Chair: Célia Paquay

Thursday 13:30 - 14:50 Continuous models
Room 126 - Chair: Nicolas Gillis

Thursday 13:30 - 14:50 Integer programming
Room 120 - Chair: Bernard Fortz

Thursday 15:20 - 16:20 Material handling and warehousing 1
Room 138 - Chair: Greet Vanden Berghe

Thursday 15:20 - 16:20 Operations management
Room 130 - Chair: Roel Leus

Thursday 15:20 - 16:20 Matrix factorization
Room 126 - Chair: Pierre Kunsch

Thursday 16:30 - 17:10 Material handling and warehousing 2
Room 138 - Chair: Katrien Ramaekers

Thursday 16:30 - 17:10 Routing and local search
Room 130 - Chair: An Caris

Thursday 16:30 - 17:10 Traffic management
Room 126 - Chair: Joris Walraevens

Thursday 16:30 - 17:10 Pharmaceutical supply chains
Room 120 - Chair: Bart Smeulders

Friday 10:50 - 12:10 Optimization in health care
Room 138 - Chair: Jeroen Beliën
  • Staff Scheduling at a Medical Emergency Service: a case study at Instituto Nacional de Emergência Médica
    Hendrik Vermuyten (KU Leuven, Campus Brussels)
    Co-authors: Joana Namorado Rosa; Inês Marques; Jeroen Beliën; Ana Barbosa-Póvoa
    Abstract:
    This presentation addresses a real-life personnel scheduling problem at a medical emergency service. In a first step, the problem is formulated as an integer program. However, the problem turns out to be too complex for a commercial IP solver for realistic problem instances. For this reason, two heuristics are developed, namely a diving heuristic and a variable neighbourhood decomposition search (VNDS) heuristic. The diving heuristic reformulates the problem by decomposing on the staff members. The LP relaxation is then solved using column generation. After the column generation phase has finished, integer solutions are found by heuristically branching on all variables with a value above a certain threshold until the schedule has been fixed for each staff member. Additionally, two different column generation schemes are compared. The VNDS heuristic consists of a local search phase and a shake phase. The local search phase uses the principles of fix-and-optimise in combination with different neighbourhoods to iteratively improve the current solution. After a fixed number of iterations without improvement, the search moves to the shake phase in which the solution is randomly changed to allow the heuristic to escape local optima and to diversify the search. The performance of both heuristics is tested on a real-life case study at Instituto Nacional de Emerg\^{e}ncia M\'{e}dica (INEM) as well as nineteen additional problem instances of varying dimensions. Four of these instances are derived from the INEM dataset by changing one of the problem dimensions, while an instance generator was built to construct the fifteen other instances. Results show that the VNDS heuristic clearly outperforms both diving heuristic implementations and a state-of-the-art commercial IP solver. In only hour of computation time, it finds good solutions with an average optimality gap of only 4.76 percent over all instances. The solutions proposed by the VNDS are then compared with the actual schedule implemented by INEM. To facilitate this comparison, the heuristic is implemented in a scheduling tool with an attractive graphical user interface. For six choices of objective function weights, which put different emphases on the relative importance of the various soft constraints, schedules are constructed by the VNDS. Each of the six schedules is compared with the actual schedule implemented by INEM and evaluated on eight key performance indicators (KPIs). All proposed schedules outperform the real schedule. Finally, two what-if scenarios are analysed to illustrate the impact of managerial decisions on the quality of the schedules and the resulting employee satisfaction.
  • Home chemotherapy: optimizing the production and administration of drugs.
    Véronique François (HEC Liège - Management School of the University of Liège)
    Co-authors: Yasemin Arda, Diego Cattaruzza, Maxime Ogier
  • An analysis of short term objectives for dynamic patient admission scheduling
    Yi-hang Zhu (KU Leuven)
    Co-authors: Túlio A. M. Toffolo, Wim Vancroonenburg, Greet Vanden Berghe
  • Robust Kidney Exchange Programs
    Bart Smeulders (HEC Liège - Management School of the University of Liège)
    Co-authors: Yves Crama, Frits C.R. Spieksma

Friday 10:50 - 12:10 Network design
Room 130 - Chair: Jean-Sébastien Tancrez

Friday 10:50 - 12:10 Local search methodology
Room 126 - Chair: Patrick De Causmaecker

Friday 10:50 - 12:10 ORBEL Award
Room 120 - Chair: Frits Spieksma

    Friday 13:00 - 14:00 Production and inventory management
    Room 138 - Chair: Tony Wauters

    Friday 13:00 - 14:00 Logistics 4.0
    Room 130 - Chair: Thierry Pironet

    Friday 13:00 - 14:00 Data clustering
    Room 126 - Chair: Yves De Smet

    Friday 13:00 - 14:00 Collective decision making
    Room 120 - Chair: Bernard De Baets

    Friday 14:10 - 15:10 Sport scheduling
    Room 138 - Chair: Dries Goossens

    Friday 14:10 - 15:10 Discrete choice modeling
    Room 130 - Chair: Virginie Lurkin

    Friday 14:10 - 15:10 Data classification
    Room 126 - Chair: Ashwin Ittoo

     
     
      ORBEL - Conference chair: Prof. A. Arda - Platform: Prof. M. Schyns.