44 research outputs found
A note on capacitated lot sizing with setup carry-over
The "Capacitated lot sizing problem with setup carry-over" is based ort the well known "Capacitated lot sizing problem" and incorporates the possibility of preserving a setup-state from a period to the following. Sox and Gao [2] decompose their formulation of the first one (GCLP1) by Lagrangian relaxation. For obtaining a heuristic solution of the GCLP1 they use subgradient optimization and a dynamic programming algorithm to solve the corresponding subproblems optimally. The present paper elucidates that this algorithm does not necessarily provide the optimal solution of the subproblem. Additionally, two improved approaches are presented. The first is an extension of the one proposed by [2] while the second is supplementary based on a slight modification of the underlying model
Mixed integer programming in production planning with backlogging and setup carryover : modeling and algorithms
This paper proposes a mixed integer programming formulation for modeling the capacitated multi-level lot sizing problem with both backlogging and setup carryover. Based on the model formulation, a progressive time-oriented decomposition heuristic framework is then proposed, where improvement and construction heuristics are effectively combined, therefore efficiently avoiding the weaknesses associated with the one-time decisions made by other classical time-oriented decomposition algorithms. Computational results show that the proposed optimization framework provides competitive solutions within a reasonable time
Traveling Baseball Players' Problem in Korea
We study the so-called the traveling tournament problem (TTP), to find an
optimal tournament schedule. Differently from the original TTP, in which the
total travel distance of all the participants is the objective function to
minimize, we instead seek to maximize the fairness of the round robin
tournament schedule of the Korean Baseball League. The standard deviation of
the travel distances of teams is defined as the energy function, and the
Metropolis Monte-Carlo method combined with the simulated annealing technique
is applied to find the ground state configuration. The resulting tournament
schedule is found to satisfy all the constraint rules set by the Korean
Baseball Organization, but with drastically increased fairness in traveling
distances.Comment: 8 pages, 4 figure
A branching scheme for minimum cost tournaments with regard to real-world constraints
Single round robin tournaments are a well-known class of sports leagues schedules. We consider leagues with a set T of n teams where n is even. Costs are associated with each possible match. Moreover, stadium availability, fixed matches, and regions’ capacities are taken into account. The goal is to find the minimum cost tournament among those having the minimum number of breaks and being feasible with regard to these additional constraints. A branching scheme is developed where branching is done by fixing a break for a team. Thus, the focus is on identifying breaks leading to an infeasible home away pattern set in order to avoid the resulting infeasible subtrees of a branch and bound tree.
A branching scheme for minimum cost tournaments with regard to real-world constraints
Single round robin tournaments are a well-known class of sports leagues schedules. We consider leagues with a set T of n teams where n is even. Costs are associated with each possible match. Moreover, stadium availability, fixed matches, and regions' capacities are taken into account. The goal is to find the minimum cost tournament among those having the minimum number of breaks and being feasible with regard to these additional constraints. A branching scheme is developed where branching is done by fixing a break for a team. Thus, the focus is on identifying breaks leading to an infeasible home away pattern set in order to avoid the resulting infeasible subtrees of a branch and bound tree. Journal of the Operational Research Society (2011) 62, 2133-2145. doi: 10.1057/jors.2010.185 Published online 2 March 201
ReplenishmentProblemWithMultipleArticlesAndAnOrderThreshold
These are the raw data sets used in the computational study in "The replenishment problem with multiple articles and an order threshold" by Dirk Briskorn and Thomas Wensin
Evaluating the emission reduction potential of scheduling locks on inland waterways
Locks constitute a bottleneck along many inland waterways. We consider the problem of scheduling a system of multiple locks arranged in a sequence, a setting that occurs naturally along many inland waterways. We provide two alternative mathematical programming models and evaluate their performance. In particular, we show how ship speed can be included as a variable, which allows to consider the emissions of ships passing through the system. We then use the models to investigate the trade-off between total flow-time and emissions on instances based on realistic problem instances.status: publishe
ReplenishmentProblemWithMultipleArticlesAndAnOrderThreshold
These are the raw data sets used in the computational study in "The replenishment problem with multiple articles and an order threshold" by Dirk Briskorn and Thomas Wensin