Single-machine scheduling with time window-dependent processing times

International audienceIn the one-machine scheduling problems analysed in this paper, the processing time of a job depends on the time at which the job is started. More precisely, the horizon is divided into time windows and with each one a coefficient is associated that is used to determine the actual processing time of a job starting in it. Two models are introduced, and one of them has direct connections with models considered in previous papers on scheduling problems with time-dependent processing times. Various computational complexity results are presented for the makespan criterion, which show that the problem is NP-hard, even with two time windows. Solving procedures are also proposed for some special cases

Flexible Job-Shop Scheduling with Batching for Semiconductor Manufacturing

International audienceScheduling decisions in the diffusion and cleaning area of a semiconductor manufacturing facilityhave an important impact on the overall performance of a plant. Consequently, we wantto optimize those decisions while taking real-world constraints into account. An importantproperty of machines in this work area is their batching capability: They can perform multipleoperations at the same time. We want to take account of this in our algorithm.We need to schedule a given set of jobs. For each of them, a fixed sequence of operations mustbe performed. This sequence is called the route of the job. Operations can only be performed onqualified machines and their processing durations depend on the selected machine. A capacitylimit constrains the number of jobs that can be processed per batch. Each operation is assignedto a family and only operations of the same family can be combined in the same batch. Foreach job, we are given a ready date and a due date. Those constraints describe a flexiblejob-shop scheduling problem with batching. We aim to minimize total weighted tardiness.For the described problem, we present a simulated annealing algorithm that is based on anextended evaluation of disjunctive graphs. In our proposed approach, batching decisions aretaken dynamically during graph traversal

Scheduling job families on non identical parallel machines under Run-To-Run control constraints

International audienceNew challenges are arising when solving scheduling problems in semiconductor manufacturing plants (fabs) with Advanced Process Control (APC) constraints. In particular, a Run-To-Run (R2R) control loop for a given product on a machine requires to regularly collect data for the product on the machine. This paper aims at introducing and modeling a new scheduling problem in which there is a time constraint on jobs of the same product, i.e. the time interval between two consecutive jobs of the same product should be smaller than a given threshold. Two Mixed Integer Linear Programming models are presented for scheduling jobs on non-identical parallel machines with setup times

Smoothing Procedures for an Integrated Approach for Multi-Level Lot Sizing and Detailed Scheduling

International audienceThe integration of production planning and scheduling decisions represents an important challenge in production management. Typical Enterprise Resource Planning (ERP) systems, using Manufacturing Resource Planning (MRP-II) technique for capacity management, cannot guarantee feasible procurement and production plans at the operational level (short term planning horizon). In this paper we study the integrated multi-level lot-sizing and job-shop scheduling problem. We analyze various smoothing procedures that "repair" the relaxed capacity and Bill-Of-Materials (BOM) constraints in the Lagrangian heuristic of a recent approach

Improvements of An Integrated Approach for Lot Sizing and Detailed Scheduling

4 pagesInternational audienceIn a previous work, we developed an integrated approach for determining optimal feasible production plans, i.e. lot sizes for which there is at least one schedule in which lots are completed on time. Based on the limitations of this approach, we propose various improvements in di fferent parts. The most relevant improvements are summarized in this extended abstract

Simulation of aircraft maintenance improvement using RFID systems

International audienceThe paper describes the maintenance process applied to an aircraft part along periodic maintenance operations and/or failure repairs. This paper deals with the assessment of RFID (Radio Frequency IDentification) technology contribution to the follow-up of aircraft parts. The construction of a simulation model and validation of the study are based on both experts' knowledge and data on flight and maintenance operations. Each stage of the maintenance process is modelled in terms of time (average times and boundaries) and the transition probability between stages. The impact of RFID technologies in the overall maintenance process is assessed. The main use of the analysis is the evaluation of different maintenance strategies and a first quantification of the impacts related to introducing RFID in maintenance processes. It should be helpful to support the decisions on RFID integration. The model could be used to design a decision support tool for maintenance designers and managers

Impact of RFID technologies on helicopter processes: Assessment on customer oriented indicators

International audienceThis paper deals with the introduction of RFID (Radio Frequency IDentification) technologies on board of helicopters. These technologies can help to support the traceability of aircraft parts during their entire lifecycle. RFID technologies are widely used within logistics processes. Today, the challenge is to use them to follow the maintenance of parts on helicopters. The chip of RFID tags will store the part identification and the associated usage data. On-board technologies are expensive to embed because of hardening requirements. The development of the information system will also generate a significant cost. To counterbalance the costs, the added value of such technologies within the aeronautical context and the potential improvements for both the aircraft manufacturer and the final operator have to be analyzed. This paper emphasizes the advantages of RFID technologies and quantifies the expected benefits of their integration

New Integrated Approach For Solving Multi-level Lot Sizing and Scheduling problems

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Nouvelle méthode intégrée pour résoudre le problème de planification et d'ordonnancement

2 pagesInternational audienceUne nouvelle méthode pour résoudre de manière intégrée le problème de planification et d'ordonnancement de la production dans des systèmes multi-niveaux est présentée. Des contraintes de capacité détaillées et de nomenclature sont inclues dans le modèle de planification, de manière à garantir des solutions réalisables. Une heuristique Lagrangienne et une heuristique de lissage sont utilisées pour résoudre le problème

Affectation optimisée des ressources de déchargement/chargement et de transport dans un terminal à conteneurs multimodal

Nous présentons un programme linéaire mixte pour représenter un terminal à conteneur pour déterminer une affectation de ressources optimisée afin de minimiser les délais des modes de transport terrestre tout en respectant les délais imposés des navires