Parallel machine scheduling with precedence constraints and setup times

This paper presents different methods for solving parallel machine scheduling problems with precedence constraints and setup times between the jobs. Limited discrepancy search methods mixed with local search principles, dominance conditions and specific lower bounds are proposed. The proposed methods are evaluated on a set of randomly generated instances and compared with previous results from the literature and those obtained with an efficient commercial solver. We conclude that our propositions are quite competitive and our results even outperform other approaches in most cases

The energy scheduling problem: Industrial case-study and constraint propagation techniques

This paper deals with production scheduling involving energy constraints, typically electrical energy. We start by an industrial case-study for which we propose a two-step integer/constraint programming method. From the industrial problem we derive a generic problem,the Energy Scheduling Problem (EnSP). We propose an extension of specific resource constraint propagation techniques to efficiently prune the search space for EnSP solving. We also present a branching scheme to solve the problem via tree search.Finally,computational results are provided

Влияние предварительного деформирования на ударную вязкость образца Шарпи при разрушении

Предложен подход к оценке величины ударной вязкости образца Шарпи на верхнем шельфе в зависимости от степени предварительного пластического деформирования металлопроката. Выполнен анализ полученных аналитических зависимостей и определены основные параметры, характеризующие их изменения. Предложена простая инженерная зависимость позволяющая оценить изменение ударной вязкости образца Шарпи на верхнем шельфе в зависимости от степени пластического деформирования при изготовлении и монтаже элементов металлоконструкций.An approach is proposed to evaluation of upper shelf impact toughness of a Charpy sample depending on the degree of plastic pre-deformation of metal rolled stock. The derived analytical dependencies have been analyzed, and the main parameters have been determined, characterizing their change. A simple engineering dependence is proposed, which allows evaluation of the change of upper shelf impact toughness of a Charpy sample depending on the degree of plastic deformation in fabrication and assembly of metal structure elements

Schedule generation schemes for the job-shop problem with sequence-dependent setup times: dominance properties and computational analysis

We consider the job-shop problem with sequence-dependent setup times. We focus on the formal definition of schedule generation schemes (SGSs) based on the semi-active, active, and non-delay schedule categories. We study dominance properties of the sets of schedules obtainable with each SGS. We show how the proposed SGSs can be used within single-pass and multi-pass priority rule based heuristics. We study several priority rules for the problem and provide a comparative computational analysis of the different SGSs on sets of instances taken from the literature. The proposed SGSs significantly improve previously best-known results on a set of hard benchmark instances

Implications of technological changes in vehicle routing interfaces for planners' constraint processing

International audienceThis study sought to assess the consequences of technological changes in vehicle routing interfaces for planners' constraint processing during route selection. We began by developing a model of domain constraints for the generic vehicle routing problem, in order to characterize planners' constraint processing and assess the visibility of constraints on different routing interfaces. An experiment featuring vehicle routing problems was then designed to test interfaces reflecting technological changes, including automation leading to simplified interfaces and the display of multiple routes computed by algorithms. Twelve participants who had worked for a small transport company for nine months were exposed to all these interfaces. Mental workload, performance and decision-making times were measured. Results revealed that automation decreases mental workload and decision times, attributable to the abridged (vs. unabridged) display of constraints on the interface. Results also showed that the perceptual (vs. analytical) display of routes greatly decreases decision times and enhances performances

Programme national sur le déterminisme du recrutement

Une vingtaine de modèles globaux de production comportant une variable climatique ont été proposés (Fréon, 1986). CLIMPROD est un système expert qui permet de choisir, parmi ces modèles, le mieux adapté au stock considéré en fonction de critères objectifs ou empiriques. Le modèle retenu est ensuite ajusté aux données par régression non-linéaire, puis validé par des tests non-paramétriques (jacknife). A partir de quelques exemples pris dans des régions de remontées d'eau profonde, on montre les possibilités du logiciel, son intérêt et ses limites. L'exemple du stock de crevettes du Panama est analysé plus en détail. (Résumé d'auteur

Scheduler-oriented algorithms to improve human-machine cooperation in transportation scheduling support systems

International audienceA decision support system designed to enhance human-machine interaction in transportation scheduling is proposed. We aim to integrate human factors and ergonomics from the beginning of the design phase and to propose a system fitted with enough flexibility to be able to deal with the characteristics of a dynamic context such as transportation scheduling. In this interdisciplinary approach, a link is done between problem solving methods (operations research techniques and data classification algorithms) and human-machine interaction (solving control modes). A set of scheduler-oriented algorithms favouring human-machine cooperation for problem solving is proposed. Some of these algorithms have been efficiently tested on instances of the literature. Finally, an original framework aiming to assist scheduler in constraint relaxation when the problem becomes infeasible is proposed and evaluated