Habillage de surfaces de révolution
Flow Polyhedra and Resource Constrained Project Scheduling Problems
This paper aims at describing the way Flow machinery may be used in order to deal with Resource Constrained Project Scheduling Problems (RCPSP). In order to do it, it first introduces the Timed Flow Polyhedron related to a RCPSP instance. Next it states several structural results related to connectivity and to cut management. It keeps on with a description of the way this framework gives rise to a generic Insertion operator, which enables programmers to design greedy and local search algorithms....
Editorial. The MODE/ROADEF 2008 Conference
Flots entiers et multiflots fractionnaires couplés par une contrainte de capacité
Nous modélisons ici plusieurs problèmes de Transport et de Gestion de Flux à l’aide d’un flot entier et d’un multiflot fractionnaire couplés par une contrainte de capacité. Pour le problème ainsi obtenu, nous proposons différents schémas de résolution par relaxation et décomposition, qui induisent la recherche d’un flot auxiliaire dont la partie entière supérieure doit minimiser un certain coût, et qui requièrent la mise en œuvre d’un processus d’agrégation. Nous en déduisons diverses heuristiques...
Flots entiers et multiflots fractionnaires couplés par une contrainte de capacité
Nous modélisons ici plusieurs problèmes de Transport et de Gestion de Flux à l'aide d'un flot entier et d'un multiflot fractionnaire couplés par une contrainte de capacité. Pour le problème ainsi obtenu, nous proposons différents schémas de résolution par relaxation et décomposition, qui induisent la recherche d'un flot auxiliaire dont la partie entière supérieure doit minimiser un certain coût, et qui requièrent la mise en œuvre d'un processus d'agrégation. Nous en déduisons diverses heuristiques...
Polyhedral Reformulation of a Scheduling Problem And Related Theoretical Results
We deal here with a scheduling problem () which is an extension of both the well-known and the . We first propose a reformulation of : according to it, solving means finding a vertex of the of an . Next, we state several theoretical results related to this reformulation process and to structural properties of this specific (connectivity, ...). We end by focusing on the preemptive case of and by identifying specific instances of which are such that any vertex of the related may be projected...
Cooperative networks games with elastic demands
We present here a pricing model which is an extension of the cooperative game concept and which includes a notion of elastic demand. We present some existence results as well as an algorithm, and we conclude by discussing a specific problem related to network pricing.
Tree based models and algorithms for the preemptive asymmetric Stacker Crane problem
In this paper we deal with the preemptive asymmetric stacker crane problem in a heuristic way. We first present some theoretical results which allow us to turn this problem into a specific tree design problem. We next derive from this new representation an integer linear programming model together with simple and efficient greedy and local search heuristics. We conclude by presenting experimental results which aim at both testing the efficiency of our heuristic and evaluating the impact of the...
Cœur et nucléolus des jeux de recouvrement
Lagrangean Heuristic for a Multi-Plant Lot-Sizing Problem with Transfer and Storage Capacities
The paper addresses a multi-item, multi-plant lot-sizing problem with transfer costs and capacity constraints. The problem is reformulated according to a multi-commodity flow formalism, and decomposed, through Lagrangean relaxation, into a master facility location problem and a slave minimal cost multi-commodity flow problem. The decomposition framework gives rise in a natural way to designing a Lagrangean based heuristic. Numerical experiments showing the efficiency of the proposed approach are...
Coeur et nucléolus des jeux de recouvrement
A cooperative game is defined as a set of players and a cost function. The distribution of the whole cost between the players can be done using the core concept, that is the set of all undominated cost allocations which prevent players from grouping. In this paper we study a game whose cost function comes from the optimal solution of a linear integer covering problem. We give necessary and sufficient conditions for the core to be nonempty and characterize its allocations using linear programming...
Tree based models and algorithms for the preemptive asymmetric Stacker Crane problem
In this paper we deal with the preemptive asymmetric stacker crane problem in a heuristic way. We first present some theoretical results which allow us to turn this problem into a specific tree design problem. We next derive from this new representation an integer linear programming model together with simple and efficient greedy and local search heuristics. We conclude by presenting experimental results which aim at both testing the efficiency of our heuristic and evaluating the impact of the...
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