The multi-item capacitated lot-sizing problem with setup times and shortage costs

International audienceWe address a multi-item capacitated lot-sizing problem with setup times and shortage costs that arises in real-world production planning problems. Demand cannot be backlogged, but can be totally or partially lost. The problem is NP-hard. A mixed integer mathematical formulation is presented. Our approach in this paper is to propose some classes of valid inequalities based on a generalization of Miller et al. [A.J. Miller, G.L. Nemhauser, M.W.P. Savelsbergh, On the polyhedral structure of a multi-item production planning model with setup times, Mathematical Programming 94 (2003) 375–405] and Marchand and Wolsey [H. Marchand, L.A. Wolsey, The 0–1 knapsack problem with a single continuous variable, Mathematical Programming 85 (1999) 15–33] results. We also describe fast combinatorial separation algorithms for these new inequalities. We use them in a branch-and-cut framework to solve the problem. Some experimental results showing the effectiveness of the approach are reported

A Metaheuristic Method for the Multi Trip Vehicle Routing Problem

National audienceIn recent years the number of passengers and freight vehicles increased in urban areas causing traffic congestion and increasing air and noise pollution. The need of an efficient distribution system that takes into account distribution cost, but at the same time considers environmental aspects aims the concept of city logistics. Vehicles could have limited capacity, due to laws restriction imposed and the narrowness of streets that characterize historical parts of downtowns. Then, it seems normal to allow vehicles accomplish several trips during the working day. MTVRP arises in this context. A MA is proposed to face the problem

Localisation de plateformes logistiques en milieu urbain

Depuis une dizaine d'années, la logistique urbaine suscite l'intérêt de bon nombre de chercheurs de communauté et nationalité variées. L'objet du travail présenté ici porte sur la localisation de plateformes logistiques dans des zones urbaines denses

The Multi Trip Vehicle Routing Problem with Time Windows and Release Dates

The Multi-Trip Vehicle Routing Problem with Time Windows and Release Dates is a variant of the Multi-Trip Vehicle Routing Problem where a time windows is associated with each customer and a release date is associated with each merchandise to be delivered at a certain client. The release date represents the moment the merchandise becomes available at the depot for final delivery. The problem is relevant in city logistics context, where delivery systems based on city distribution centers (CDC) are studied. Trucks arrive at the CDC during the whole working day to deliver goods that are transferred to eco-friendly vehicles in charge of accomplish final deliveries to customers. We propose a population-based algorithm for the problem based on giant tour representation of the chromosomes as well as a split procedure to obtain solutions from individuals

Plates-formes en centre ville pour la Logistique Urbaine: étude sur la ville de Marseille

International audienceCette étude, conduite dans le cadre du projet PLUME, se propose d'évaluer l'intérêt de la mise en œuvre de systèmes de distribution urbaine à partir de Zones Logistiques Urbaines. Nous visons à définir d'un point de vue organisationnel et fonctionnel les atouts économiques, environnementaux et sociétaux de ces systèmes; le but étant de fournir un cadre méthodologique pour guider leur mise en place. Un premier terrain d'analyse pour notre étude sera la ville de Marseille qui possède la particularité de disposer d'une ZLU en cœur de centre-ville avec la plate-forme logistique d'ARENC (41362 m2 d'entrepôts et de bureaux). Dans cet article, nous proposons de définir plus précisément notre problématique avant de donner un bref état de l'art des problèmes classiques de la Recherche Opérationnelle se rattachant à notre étude (Facility Location Problem, Network Design Problem et Green Logistics). Nous établissons enfin une liste d'éléments que nous chercherons à prendre en compte dans un modèle général

A modeling approach for locating logistics platforms for fast parcels delivery in urban areas

International audienceThis study aims at defining a framework for optimizing, in a sustainable way (i.e. economical, eco-friendly and societal), the location of logistics platforms in urban areas. A first case study for our work is the city of Marseilles (France) which already has a logistics platform right in its centre (ARENC: 41362 m2 of warehouses and offices). In this abstract, we first provide a precise description of the problem we intend to solve. We then propose a mathematical model for representing it. Preliminary experimentations, based on the city of Marseilles, are then described; figures and preliminary results which are proposed for this first case study are obtained thanks to a decision-making software we have implemented. Conclusions and future works are finally drawn

A relax-and-repair heuristic for the Swap-Body Vehicle Routing Problem

International audienceIn this paper we address the Swap-Body Vehicle Routing Problem, a variant of the Truck and Trailer Routing Problem. It was introduced in the VeRoLog Challenge 2014. We develop a solution approach that we coin Relax-and-Repair. It consists in solving a relaxed version of the SB-VRP and deriving a feasible solution by repairing the relaxed one. We embed this approach within a population-based heuristic. During computation we store all feasible routes in order to derive better solutions by solving a set-partitioning problem. In order to take advantages of nowadays multi-core machines, our algorithm is designed as a collaborative parallel population-based heuristic. Experimental results show that our relax-and-repair algorithm is very competitive and point the impact of each phase on the quality of the obtained solutions. The advantage of our approach is that it can be adapted to solve complex industrial routing problems

The City Logistics Facility Location Problem

National audienceThe aim of this work is to propose a new model that we call the City Logistics Facility Location Problem (CLFLP). Our purpose when introducing the CLFLP, is to capture essential aspects of distribution in cities, while maintaining a reasonable level of genericity and simplicity in the defintion of the problem. Practically, this model was adapted to the case of the city of Marseilles (France) and inserted into a Decision Support System. With a more academic point of view, the model could serve as a cornerstone for the development of new models and methods for strategic issues in city logistics

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

The Multi Trip Vehicle Routing Problem with Time Windows and Release Dates

International audienceIn this paper the Multi Trip Vehicle Routing Problem with Time Windows and Release Dates is introduced. The problem is particularly interesting in the City Logistics context, where trucks deliver merchandise to depots located in the outskirts of the city. Goods continuously arrive during the day becoming available for final distribution after the working day has started. This introduces the concept of release dates associated with merchandise. In this paper, a set of instances is introduced and a hybrid genetic algorithm is proposed to solve the problem