ORBEL 27

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Detailed schedule

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Thursday 7 February:

9:00-9:30Registration (Room Spina)
9:30-10:45Plenary session
Welcome
Invited speaker: El-Ghazali Talbi
Metaheuristics for multi-objective optimization - A unified view
10:45-11:15Coffee break
11:15-12:30Parallel sessions
  TA-1: COMEX Decision Making
Chair: B. Fortz
Room: C.611
TA-2: Production 1
Chair: E.h. AGhezzaf
Room: C.601
TA-3: Global Optimization
Chair: D. Claeys
Room: C.602
TA-4: Transportation 1
Chair: C. Vanovermeire
Room: C.603
12:30-14:00Lunch
14:00-15:40Parallel sessions
  TB-1: COMEX Health
Chair: G. Vanden Berghe
Room: C.611
TB-2: Routing
Chair: G.K. Janssens
Room: C.601
TB-3: Meta-Heuristics
Chair: P. Vansteenwegen
Room: C.602
TB-4: Transportation 2
Chair: F.C.R Spieksma
Room: C.603
15:40-16:10Coffee break
16:10-17:25Parallel sessions
  TC-1: COMEX Routing
Chair: K. Sôrensen
Room: C.611
TC-2: Sets, Relations and Rankings
Chair: B. De Baets
Room: C.601
TC-3: Logistics
Chair: S. Demeyer
Room: C.602
 
17:30-General Assembly (Room C.611)
19:30-Conference dinner (Carlton)

Friday 8 February
9:00-10:15Parallel sessions
  FA-1: COMEX Logistics
Chair: Y. Crama
Room: C.611
FA2: Production 2
Chair: D. Tuyttens
Room: C.611
FA-3: MIP
Chair: T. Dokka
Room: C.603
 
10:15-10:40Coffee break
10:40-12:40Plenary session
ORBEL Award
Wolsey award announcement
Invited speaker: Andrea Schaerf
Educational Timetabling: Problems, Benchmarks, Algorithms, Software Tools, and Practical Issues
12:40-14:00Lunch
14:00-14:30IMinds Information Session (Room C.611)
14:30-16:10Parallel sessions
  FB-1: COMEX automatic tuning and organization
Chair: T. Stützle
Room: C.611
FB2: Disaster, Water and Biology
Chair: L. Porretta
Room: C.602
FB-3: Decision Making
Chair: D. Goossens
Room: C.603
 
16:10-16:40Coffee break


Thursday 11:15-12:30 TA-1: COMEX Decision Making
Room C.611 - Chair: B. Fortz

Thursday 11:15-12:30 TA-2: Production 1
Room C.601 - Chair: E.h. AGhezzaf

Thursday 11:15-12:30 TA-3: Global Optimization
Room C.602 - Chair: D. Claeys

Thursday 11:15-12:30 TA-4: Transportation 1
Room C.603 - Chair: C. Vanovermeire

Thursday 14:00-15:40 TB-1: COMEX Health
Room C.611 - Chair: G. Vanden Berghe

Thursday 14:00-15:40 TB-2: Routing
Room C.601 - Chair: G.K. Janssens

Thursday 14:00-15:40 TB-3: Meta-Heuristics
Room C.602 - Chair: P. Vansteenwegen

Thursday 14:00-15:40 TB-4: Transportation 2
Room C.603 - Chair: F.C.R Spieksma
  • Optimisation model for empty container repositioning. (PDF)
    Frederic Salmon (HEC-ULg QuantOM)
    Co-authors: S.Limbourg
  • The Red-Blue Transportation Problem (PDF)
    Wim Vancroonenburg (KU Leuven - KAHO Sint-Lieven)
    Co-authors: Federico Della Croce, Dries Goossens, Frits Spieksma
  • The ship placement problem: Decision support through exact decomposition (PDF)
    Jannes Verstichel (KU Leuven - KAHO Sint-Lieven)
    Co-authors: Patrick De Causmaecker, Greet Vanden Berghe
  • The lockmaster's problem: a computational study (PDF)
    Ward Passchyn (KU Leuven)
    Co-authors: S. Coene; F. C. R. Spieksma; G. Vanden Berghe; D. Briskorn; J. L. Hurink
    Abstract:
    Transportation of goods by ship is a promising alternative for transport over land. We focus on transport by ships over inland waterways and transport by sea ships entering a harbor/waterway network by passing through one or multiple locks. Locks are needed to control the water level so that large and heavy ships can continue to access the corresponding waterways. The lockmaster's problem concerns the optimal strategy for operating such a lock. We describe a very basic situation that will act as our core problem. Consider a lock consisting of a single chamber. Ships arrive both upstream and downstream of the lock at known arrival times. The lockage duration T is the time between closing the lock for entering ships, and opening the lock so that ships can leave. We assume that all data are integral and that the lockage duration is constant. Our goal is to find a feasible lock-strategy that minimizes total waiting time of all ships. Thus, we need to determine at which moments in time the lock should move and transport ships to the other side. The optimal solution is obtained by finding a shortest path in a graph. We first note that in an optimal schedule, all lock moves start at the arrival of a ship or at the arrival of the lock. We define a block as a sequence of consecutive up and down movements followed by a waiting period of less than 2T time units. It is shown that an optimal schedule exists that is a sequence of blocks. We build the graph by adding an edge for each of these possible blocks with a weight equal to the waiting time of the ships in this block. This gives an acyclic graph with O(n^2) edges where n is the total number of ships. The shortest s-t path then corresponds to a solution with the lowest possible waiting time. A straightforward implementation of this graph yields an algorithm with O(n^3) time complexity. A further speed-up of the algorithm can be achieved to O(n^2). This algorithm can also be used to solve certain single machine batch scheduling problems more efficiently than the current algorithms from literature do. Relevant extensions that take into account the lock's capacity, the different priorities of ships, the water usage of a lock, and the possibility of multiple chambers, can be dealt with by slightly modifying the basic algorithm. Further, we prove that the problem with multiple non-identical chambers is strongly NP-hard when the number of chambers is part of the input. A computational study is performed to evaluate some basic heuristics and the optimal solution algorithm developed here. The heuristics are a number of straightforward strategies to operate the lock, assuming near complete lack of information. A lock operator knows only the number of ships waiting on either side of the lock. We use a set of problem instances from literature for similar lock scheduling problems.

Thursday 16:10-17:25 TC-1: COMEX Routing
Room C.611 - Chair: K. Sôrensen

Thursday 16:10-17:25 TC-2: Sets, Relations and Rankings
Room C.601 - Chair: B. De Baets

Thursday 16:10-17:25 TC-3: Logistics
Room C.602 - Chair: S. Demeyer

Friday 9:00-10:15 FA-1: COMEX Logistics
Room C.611 - Chair: Y. Crama

Friday 9:00-10:15 FA2: Production 2
Room C.611 - Chair: D. Tuyttens

Friday 9:00-10:15 FA-3: MIP
Room C.603 - Chair: T. Dokka

Friday 14:00-15:40 FB-1: COMEX automatic tuning and organization
Room C.611 - Chair: T. Stützle

Friday 14:00-15:40 FB2: Disaster, Water and Biology
Room C.602 - Chair: L. Porretta

Friday 14:00-15:40 FB-3: Decision Making
Room C.603 - Chair: D. Goossens

 
 
  SOGESCI/ORBEL - Conference chair: Prof. P. De Causmaecker - Platform: Prof. M. Schyns