ORBEL 32

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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

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
    • Scheduling time-relaxed double round-robin tournaments with availability constraints
      David Van Bulck (Ghent University)
      Co-authors: Dries Goossens
      Abstract:
      Over the last four decades, operations-research has successfully been applied to many sports scheduling problems. Most of these problems, however, concern time-constrained round-robin tournaments, i.e. tournaments where all teams meet all other teams a fixed number of times and teams play once in a round (if the number of teams is even). This is in contrast with the limited number of papers that consider time-relaxed schedules that contain (many) more slots than there are matches per team. Since time-relaxed schedules offer more flexibility, they are widely used in (amateur) competitions where venues are typically shared and players have other activities as well. In the time-relaxed double round-robin problem with availability constraints (TRDRRA), we are given a set of teams and a set of slots. To cope with venue and player availability, each team can provide a set of dates on which it can host a game, and a set of dates on which it cannot play at all. To avoid injuries, a team should ideally rest for at least R days between two consecutive matches. However, if this is not possible, we penalize the solution with a value of p_r each time a team has only r < R days between two consecutive matches. In addition, a team can only play up to M games within a period of R+1 days. To increase the fairness of the generated schedules, we also explain how various fairness metrics can be integrated. The goal is to construct a schedule with minimum cost, scheduling all matches and respecting the availability constraints. Since most traditional methods, such as first-break-then-schedule, focus on the alternation of home and away matches in a time-constrained setting, they are not appropriate to solve our problem. Therefore, we propose two new heuristics. The first is a genetic algorithm backed by a local improvement heuristic which is able to both repair and improve schedules, resulting in a memetic algorithm. Basically, the improvement heuristic sequentially solves a transportation problem which schedules (or reschedules) all home games of a team. In this transportation problem, the set of supply nodes consists of all slots on which this team can play a home game, and the set of demand nodes consists of all opponents against whom it can play a home game. The second heuristic is a fix-and-relax heuristic procedure based on the teams as well as on time-intervals. This constructive method initially relaxes all variables. Next, it gradually replaces the fractional variables by resolving the model with the integrality constraints enabled for a small subset of relaxed variables. After each iteration, it then fixes the variable values of the selected group and repeats the procedure until all variables have an integral value. Finally, a simple ruin-and-recreate procedure tries to improve the generated solution. We assess the performance of both algorithms for several instances from the literature. Overall, the quality of the generated schedules from both heuristics is comparable with the optimal solutions obtained with integer programming (Gurobi) but the required computational effort is considerably less.
    • Combined proactive and reactive strategies for round robin football scheduling
      Xia-jie Yi (Ghent University)
      Co-authors: Dries Goossens
    • A constructive matheuristic strategy for the Traveling Umpire Problem
      Reshma Chirayil Chandrasekharan (KU Leuven)
      Co-authors: Tulio A. M. Toffolo, Tony Wauters

    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.