Structure flexible d'ordonnancements à performances contrôlées pour le pilotage d'atelier en présence de perturbations

Texte intégral accessible uniquement aux membres de l'Université de LorraineNon disponible / Not availableCette thèse traite le problème d'ordonnancement d'ateliers soumis à des perturbations. Dans un tel environnement, il est plus réaliste de fournir au décideur non pas une solution unique satisfaisante mais plutôt un ensemble de solutions garantissant une certaine qualité et offrant des degrés de liberté pour l'adaptation aux éventuelles perturbations. Nous proposons pour cela une approche de pilotage à deux niveaux. Au premier niveau intervient un algorithme proactif qui calcule une ou plusieurs structures flexibles. Une structure flexible est un ensemble d'ordonnancements caractérisés par un type et un ordre partiel entre les opérations sur chaque machine. Au second niveau intervient un algorithme réactif qui exploite la flexibilité contenue dans la structure pour guider l'exécution des tâches et réagir en présence de perturbations . L'analyse dans le pire des cas de la performance d'une structure flexible nous a conduit à l'étude de nouveaux problèmes de maximisation de critères réguliers

On the reactive scheduling design using flexible predictive schedules

Colloque avec actes et comité de lecture. internationale.International audienceWe consider single machine scheduling problem with dynamic job arrival and total weighted tardiness and makespan as objective functions. The machine is subject to disruptions related to late raw material arrival and machine breakdowns. We propose several reactive algorithms to guide the execution of the jobs and to hedge against the presence of perturbations in the shop floor. These algorithms are based on flexible predictive schedules characterized by a partial order of jobs. The efficiency of these algorithms is shown through some computational experiments

Worst-case evaluation of flexible solutions in disjunctive scheduling problems

In this paper, we consider the problem of evaluating the worst case performance of flexible solutions in non-preemptive disjunctive scheduling. A flexible solution represents a set of semi-active schedules and is characterized by a partial order on each machine. A flexible solution can be used on-line to absorb the impact of some data disturbances related for example to job arrival, tool availability and machine breakdowns. Providing a flexible solution is useful in practice only if it can be assorted with an evaluation of the complete schedules that can be obtained by extension. For this purpose, we suggest to use only the best case and the worst case performance. The best case performance is an ideal performance that can be achieved only if the on-line conditions allow to implement the best schedule among the set of schedules characterized by the flexible solution. In contrast, the worst case performance indicates how poorly the flexible solution may perform. These performances can be obtained by solving corresponding minimization and maximization problems. We focus here on maximization problems when a regular minmax objective function is considered. In this case, the worse objective function value can be determined by computing the worse completion time of each operation separately. We show that this problem can be solved by finding an elementary longest path in the disjunctive graph representing the problem with additional constraints. In the special case of the flow-shop problem with release dates and additional precedence constraints, we give a polynomial algorithm that determines the worst case performance of a flexible solution.ou

A genetic algorithm to achieve scheduling flexibility for a single machine problem

Article dans revue scientifique avec comité de lecture.We consider single machine scheduling problem with dynamic job arrival and total weighted tardiness and makespan as objective functions. The machine is subject to disruptions related to late raw material arrival and machine breakdowns. We propose a proactive-reactive approach to deal with possible perturbations. In the proactive phase, instead of providing only one schedule to the decision maker, we present a set of predictive schedules. This set is characterized by a partial order of jobs and a type of associated schedules, here semi-active schedules. This allows to dispose of some flexibility in job sequencing and flexibility in time that can be used on-line by the reactive algorithm to hedge against unforseen disruptions. In this paper, we focus on the proactive algorithm, which is based on a genetic algorithm and present some experimentations to validate that this algorithm is able, in several cases, to compute solutions (partial orders of jobs) that provide some flexibility while maintaining high shop performance

An efficient proactive reactive scheduling approach to hedge against shop floor disturbances

Colloque avec actes et comité de lecture. internationale.International audienceWe consider single machine scheduling problem with dynamic job arrivals and total weighted tardiness and makespan as objective functions. The machine is subjected to disruptions related to late raw material arrivals and machine breakdowns. We propose a proactive-reactive approach to deal with possible perturbations. In the proactive phase, instead of providing only one schedule to the decision maker, we present a set of predictive schedules. This set is characterized by a partial order of jobs and a type of associated schedules, here semi-active schedules. This allows to dispose some flexibility in job sequencing and flexibility in time that can be used on-line by the reactive algorithm to hedge against unforeseen disruptions. We conduct computational experiments which prove that our approach outperforms predictive-reactive approach particularly for disruptions with low to medium amplitude. || Nous considérons un problème d'ordonnancement à une machine avec arrivée dynamique des travaux. Les critères retenus sont la somme des retards et la durée totale. La machine est soumise à des perturbations dues à l'arrivée des composants et à des pannes

Data oriented genetic operators for one-machine scheduling problems

Colloque avec actes et comité de lecture. internationale.International audienceWe consider the one machine scheduling problem with identical release dates, sequence dependent set-up times and weighted sum of performance as performance measure. We propose new genetic operators called "data oriented" that use not only the permutation contained in the chromosome but also an analysis of the corresponding solution. The experimental results show that data oriented operators are globally better than calssical ones

A flexible proactive-reactive approach: the case of an assembly workshop

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Une approche proactive réactive efficace : Cas d'un atelier d'assemblage

Contribution à un ouvrage.Nous nous intéressons à des problèmes de chaînes logistiques que nous avons rencontrés dans le cadre du projet Européen V-chain. Nous nous plaçons au niveau d'un atelier de production en interaction avec des ateliers en amont et des ateliers en aval. Nous supposons que des délais d'arrivées au plus tôt et des dates de livraison au plus tard peuvent être négociés par rapport à l'amont et l'aval. Au lieu de fournir un seul ordonnancement sous les contraintes négociées, on fournit une famille d'ordonnancements, dite "ordonnancement proactif" (définie par un pré-ordre)et calculée de telle sorte que si l'on vérifie le pré-ordre, on obtient les garanties de performance annoncées tout en respectant l'amont et l'aval. Cet ordonnancement est ensuite soumis à des perturbations et un ordonnancement réactif utilise la flexibilité induite pour conserver autant que faire ce peut les performances annoncées. || We consider supply chain logistic problems encountered within the European project V-chain. We are concerned with a production shop in relation with upstream and downstream other shops. We assume the release dates and the dead lines can be negotiated rel