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Tarik Chargui, Anne-Laure Ladier, Abdelghani Bekrar, Shenle Pan, Damien Trentesaux. Towards designing and operating Physical Internet cross-docks: problem specifications and research perspectives. Omega, 2022, 111, pp.102641. ⟨10.1016/j.omega.2022.102641⟩. ⟨hal-03624314⟩
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Cross-docking is a common logistics practice applied in transit platforms to synchronize inbound and outbound vehicles in order to avoid keeping in-between storage. The practice plays a critical role to accelerate transportation flows. In this paper, we focus on Physical Internet (PI or π) cross-docks and discuss how this concept changes the current classical design, management and optimization of cross-docking platforms. We present the optimization problems related to cross-docks in the PI context and highlight the distinctive features of a π-cross-dock. A review of the existing literature on the main ideas and components of the π-concept, and on the design and operations of π-cross-docks (π-hubs) is firstly presented. Then, the functional design of the π-cross-dock and the classical one are discussed while highlighting the distinctive features of both configurations. The different cross-docking optimization problems arising from the PI paradigm are then specified at the strategic, tactical and operational decision levels, showing how they differ from the problems already addressed for “traditional” cross-docking platforms. Finally, as a proof of concept, a preliminary study is carried out on one of the newly specified problems.
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https://hal.science/hal-03624314/file/S0305048322000494.pdf BibTex
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Faycal Touzout, Anne-Laure Ladier, Khaled Hadj-Hamou. An assign-and-route matheuristic for the time-dependent Inventory Routing Problem. European Journal of Operational Research, 2022, 300 (3), pp.1081-1097. ⟨10.1016/j.ejor.2021.09.025⟩. ⟨hal-03354383⟩
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In this paper, we consider a variant of the Inventory Routing Problem (IRP), the Time-Dependent IRP (TD-IRP). The TD-IRP extends the routing component of the IRP by making the travelling time between two locations no longer constant but depending on the departure time. In order to investigate the relevance of considering time-dependent travelling time functions, a set of new benchmark instances based on real-data is assumed. Numerical experiments show that optimising with time-dependent travelling times is cost-efficient, but computationally challenging. Thus, we propose a matheuristic that decomposes the problem, based on the observation of the structure of optimal TD-IRP solutions. The proposed matheuristic defines the set of clients to visit and the quantity to deliver for each period first and solves the routing problem second. Numerical experiments prove it to be very efficient and yield solutions with small gaps to the best lower bounds found. Because it separates the routing problem, the proposed matheuristic opens the possibility to solve the TD-IRP very efficiently by taking advantage of the rich literature on time-dependent routing problems.
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https://hal.science/hal-03354383/file/S0377221721008006.pdf BibTex
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Faycal Touzout, Anne-Laure Ladier, Khaled Hadj-Hamou. Modelling and comparison of stability metrics for a re-optimisation approach of the Inventory Routing Problem under demand uncertainty. EURO Journal on Transportation and Logistics, 2021, 10, pp.100050. ⟨10.1016/j.ejtl.2021.100050⟩. ⟨hal-03354380⟩
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The inventory routing problem (IRP) is an optimisation problem that integrates transportation and inventory management decisions. When subjected to unexpected events such as demand changes, the a posteriori approach consists in re-optimising including the data related to this event; the challenge is to ensure that the obtained solution does not deviate too much from the original one, lest that creates important organisational issues. Therefore, a stability metric is needed when re-optimising IRP models. This article proposes a panel of stability metrics adapted from the scheduling, routing and inventory management literature to fit the requirements of the IRP and proposes mathematical formulations for the most relevant ones. A framework of comparison is proposed to validate and compare these metrics over a benchmark of 3000 instances generated from the literature. A strong correlation between the metrics is observed. Moreover, the results show that ensuring the stability of the re-optimised solutions has little impact on the initial objective, the total cost.
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https://hal.science/hal-03354380/file/S2192437621000212.pdf BibTex
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Olivier Briant, Hadrien Cambazard, Diego Cattaruzza, Nicolas Catusse, Anne-Laure Ladier, et al.. An efficient and general approach for the joint order batching and picker routing problem. European Journal of Operational Research, 2020, 285 (2), pp.497-512. ⟨10.1016/j.ejor.2020.01.059⟩. ⟨hal-02078547⟩
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Order picking is the process of retrieving products from inventory. It is mostly done manually by dedicated employees called pickers and is considered the most expensive of warehouse operations. To reduce the picking cost, customer orders can be grouped into batches that are then collected by traveling the shortest possible distance. This work presents an exponential linear programming formulation to tackle the joint order batching and picker routing problem. Variables, or columns, are related to the picking routes in the warehouse. Computing such routes is generally an intractable routing problem and relates to the well known traveling salesman problem (TSP). Nonetheless, the rectangular warehouse’s layouts can be used to efficiently solve the corresponding TSP and take into account in the development of an efficient subroutine, called oracle. We therefore investigate whether such an oracle allows for an effective exponential formulation. Experimented on a publicly available benchmark, the algorithm proves to be very effective. It improves many of the best known solutions and provides very strong lower bounds. Finally, this approach is applied to another industrial case to demonstrate its interest for this field of application.
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https://hal.science/hal-02078547/file/2019_An%20efficient%20and%20general%20approach%20for%20the%20JOBPRP.pdf BibTex
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Corentin Le Hesran, Aayush Agarwal, Anne-Laure Ladier, Valerie Botta-Genoulaz, Valérie Laforest. Reducing waste in manufacturing operations: bi-objective scheduling on a single-machine with coupled-tasks. International Journal of Production Research, 2020, 58 (23), pp.7130-7148. ⟨10.1080/00207543.2019.1693653⟩. ⟨emse-02360718⟩
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This study addresses a scheduling problem involving a single-machine with coupled-tasks and bi-objective optimisation considering simultaneously inventory and environmental waste. A Mixed Integer Linear Program representing the problem is first developed. Subsequently, a Genetic Algorithm (GA) is presented, followed by numerical experiments on multiple instances. Pareto fronts are determined using the ϵ-constraint and weighted sum methods, and a trade-off point is selected according to a distance criterion. Numerical experiments on both small and large instances show near-optimal results for small instances, and considerably reduced computing times for large ones when using the GA. The results show that a compromise can be found, with a decrease in setup-related waste up to 36% for an increase of inventory of 12%. This will help decision-makers to better consider the environmental aspect when designing schedules, as well as reduce their production environmental impact and waste-management costs.
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https://hal-emse.ccsd.cnrs.fr/emse-02360718/file/IJPR%20submission%20TPRS-2019-IJPR-0111.pdf BibTex
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Corentin Le Hesran, Anne-Laure Ladier, Valerie Botta-Genoulaz, Valérie Laforest. A methodology for the identification of waste-minimizing scheduling problems. Journal of Cleaner Production, 2020, pp.119023. ⟨10.1016/j.jclepro.2019.119023⟩. ⟨emse-02345594⟩
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Sustainability in manufacturing operations has become the subject of increasing attention in the recent years. At the operational level, knowledge about material and energy flows circulating in the production system provides information regarding costs, efficiency and environmental impact, as well as opportunities for improvements. Several methods have been proposed for flow assessment and flow cartography, but work combining production scheduling and flow assessment remains scarce. To address this issue, we propose comprehensive guidelines in order to identify waste reduction opportunities and integrate them in a scheduling problem. This work combines sustainable production principles with environmental and material flow assessment to promote waste prevention at the operational level of production, by identifying the main waste-generating activities that can be improved through scheduling. From a decision-maker's point of view, more informed choices can be made regarding the production scheduling and the opportunities for operational improvement. From a research perspective, a framework for the identification and integration of waste-minimizing opportunities in scheduling problems is proposed. Four steps permit the product system definition, flow inventory, economic and environmental impact assessment and scheduling problem identification. An application to a hub-cap production system serves to highlight the benefits of this methodology, showing that hazardous waste generation could be reduced by 10% using adequate scheduling.
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https://hal-emse.ccsd.cnrs.fr/emse-02345594/file/S0959652619338934.pdf BibTex
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Corentin Le Hesran, Anne-Laure Ladier, Valerie Botta-Genoulaz, Valérie Laforest. Operations scheduling for waste minimization: A review. Journal of Cleaner Production, 2019, 206, pp.211-226. ⟨10.1016/j.jclepro.2018.09.136⟩. ⟨emse-01885079⟩
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This article proposes a review on waste minimization at the operational level of production planning. After defining the research scope and the concept of waste minimization through scheduling, the state-of-the-art is presented. A classification based on environmental and scheduling criteria is proposed, which details the various types of scheduling problems encountered and groups them into different categories. Results show that despite having developed in the recent years, literature on waste-minimizing scheduling remains scarce and lacks a unified terminology. While research on energy-efficient scheduling has garnered a lot of attention, improving resource efficiency and reducing waste generation is also an important step towards a greener production. Thus, research perspectives for the inclusion of waste reduction concerns in scheduling are proposed based on the analysis of the literature classification.
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https://hal-emse.ccsd.cnrs.fr/emse-01885079/file/JCP%20submission%20JCLEPRO-D-18-06399%20revised%20manuscript%20-%20clean%20version.pdf BibTex
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Anne-Laure Ladier, Gülgün Alpan. Robust cross-dock scheduling with time windows. Computers & Industrial Engineering, 2016, 99, pp.16-28. ⟨10.1016/j.cie.2016.07.003⟩. ⟨hal-01344240⟩
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Cross-docking is a logistic technique that helps to accelerate the goods flow and to reduce inventory costs; but it requires a perfect coordination of the inbound and outbound trucks. The truck scheduling problem has been studied by many authors, but mainly in a deterministic case. And yet, many uncertainties can arise in the process: if a truck is delayed, or the process times change, does the truck schedule remain feasible and stable? This article proposes robust models for the truck scheduling model with time windows. The reformulations of the original model are based on classical techniques in robust optimization (minimax and minimization of the expected regret) but also on techniques from robust project scheduling (resource redundancy and time redundancy). The numerical study carried out to compare the nine different models shows that the methods based on resource redundancy give good results in the cross-docking case. Minimizing the average number of trucks docked at a given door is a good way to ensure robustness in the schedule, but it also increases storage.
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Anne-Laure Ladier, Gülgün Alpan. Cross-docking operations: Current research versus industry practice. Omega, 2016, 62, pp.145-162. ⟨10.1016/j.omega.2015.09.006⟩. ⟨hal-01222831⟩
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The technique of cross-docking, which consists in unloading trucks, sorting the items they contain and reloading them directly into outbound trucks in order to minimize temporary storage, has attracted researchers׳ attention in the past few years. The number of articles on the subject has been growing very fast, but largely detached from industry practice. In order to see whether the current state-of-the-art matches the industry practice, we propose a common framework that helps comparing the literature review regarding cross-docking operations with on-field observations and platform managers׳ interviews. Analyzing the gaps between the state-of-the-art and the industry practice helps drawing future research directions, in relation to industrial needs.
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Anne-Laure Ladier, Gülgün Alpan, Bernard Penz. Joint employee weekly timetabling and daily rostering: a decision-support tool for a logistics platform. European Journal of Operational Research, 2014, 234 (1), pp.278-291. ⟨10.1016/j.ejor.2013.10.023⟩. ⟨hal-00881714⟩
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To deal with their highly variable workload, logistics companies make their task force flexible using multi-skilled employees, flexible working hours or short-term contracts. Together with the legal constraints and the handling equipments’ capacities, these possibilities make personnel scheduling a complex task. This paper describes a model to support their chain of decisions from the weekly timetabling to the daily rostering (detailed task allocation). We divide the problem into three sub-problems depending on the type of decision to be made: (1) workforce dimensioning, (2) task allocation for a week, and (3) detailed rostering for a day. The three decisions are made sequentially, the output of a step being the input of the next one. Each step is modeled as a mixed integer linear program which is described and commented. The proposed models are tested with industrial data as well as generated instances. From the observations made in an industrial context, we show that our model is an actual management tool supporting the managers in their operational decisions. This tool is currently used by the company which provided us with the industrial data. Based on the results with the generated instances, we present the conditions under which the models can be solved within a reasonable amount of time, and we assess the robustness of the daily rostering when the input data changes.
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https://hal.science/hal-00881714/file/EJOR-D-12-01622Revision2.pdf BibTex
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Anne-Laure Ladier, Gülgün Alpan. Crossdock truck scheduling with time windows: earliness, tardiness and storage policies. Journal of Intelligent Manufacturing, 2014, 29 (3), pp.569-583. ⟨10.1007/s10845-014-1014-4⟩. ⟨hal-01178855⟩
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This article proposes to simultaneously plan inbound and outbound truck arrivals and departures in a cross-docking platform, as well as the internal pallet handling. The objective is to minimize both the total number of pallets put in storage and the dissatisfaction of the transportation providers, by creating a truck schedule as close as possible to the wished schedule they communicate in advance. The problem is modeled with an integer program tested on generated instances to assess its performance, especially regarding the computation time. The problem is proven to be np-hard in the strong sense. Since the execution takes too long to be used on a daily basis by platform managers, three heuristics are also proposed and tested. Two are based on integer programs solved sequentially, the third one is a tabu search in which the storage part of the objective function is evaluated by a maximum flow model in a graph. Numerical experiments show in which conditions each heuristic performs best, which can help choosing a solution method when confronted to a real-life problem.
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Gülgün Alpan, Anne-Laure Ladier, Rim Larbi, Bernard Penz. Heuristic solutions for transshipment problems in a multiple door cross docking warehouse. Computers & Industrial Engineering, 2011, 61 (2), pp.402-408. ⟨10.1016/j.cie.2010.09.010⟩. ⟨hal-00516918⟩
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Cross docking is a practice in logistics with the main operations of unloading products from an incoming truck, regrouping them with respect to their destinations and loading them directly into an outbound truck with minimum storage in between these operations. In this article, we study the transshipment scheduling problem in a multiple inbound and outbound dock configuration. The operations manager has several decisions to make: he can decide to transship products directly from inbound to an outbound truck, if an outbound truck is available; he can temporarily store certain products and have them loaded later on; or he can replace an outbound truck to facilitate direct loading. The objective is to find the best schedule of transshipment operations to minimize the sum of inventory holding and truck replacement costs. In this article, we present several heuristics to attain this objective. Numerical experiments are presented and the results are compared with the optimal solution to evaluate the performance of the heuristics.
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Communication dans un congrès

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Brice Cenci, Marwane Bouznif, Anne-Laure Ladier. Réarrangement d'un entrepôt automatisé avec navettes. ROADEF 2026, Université de Tours [UT], Feb 2026, Tours, France. ⟨hal-05534971⟩
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Réarrangement d'un entrepôt automatisé avec navettes
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Brice Cenci, Marwane Bouznif, Anne-Laure Ladier. Séquencer les opérations d'un entrepôt automatisé pour réduire sa consommation d'énergie. ROADEF 2026, Université de Tours [UT], Feb 2026, Tours, France. ⟨hal-05534959⟩
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Séquencer les opérations d'un entrepôt automatisé pour réduire sa consommation d'énergie
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https://hal.science/hal-05534959/file/SEQUENCING.pdf BibTex
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Paula Sofia Castro Acevedo, Yenny A. Paredes-Astudillo, Lorraine Trilling, Anne-Laure Ladier. Relationship between Supply Chain Resilience and Ramp-up Processes: Challenges, Indicators, Strategies and Enablers. Conference on Computers & Industrial Engineering (CIE52), Oct 2025, Lyon, France. ⟨hal-05351067⟩
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Modern supply chains are exposed to disruptions, often classified as macro or micro, which constrain their functionality and reduce overall performance. These disruptions can trigger sudden shifts in demand and interrupt the regular flow of goods and materials and resulting in decreased profitability, in some cases, they may also lead to positive outcomes. For instance, during COVID-19, many supply chains experienced severe demand shocks for essential products. In this context, supply systems must have two critical capabilities. The first is resilience, or the capacity to absorb, adapt to, and recover from disruptions while maintaining operational targets. The second is the ability to manage ramp-up processes, enabling firms to respond swiftly by sourcing new suppliers, redesigning products, or adapting procurement strategies that can improve competitive advantage, especially given the ripple effects that influence the entire supply chain. After an initial review, we found that ramp-up processes have not been widely examined in the supply chain resilience literature. Moreover, existing ramp-up studies typically focus on the growth phase within the context of product development, without addressing the collateral impacts across the entire supply chain. This research studies the relationship between supply chain resilience and ramp-up processes through a comprehensive literature review. The findings indicate that ramp-up activities are critical during planned disruptions and also in response to unplanned events. Ramp-up emerge as reactions to sudden surges in demand for critical goods during or after crises, while backlogs of non-essential products tend to accumulate. This article outlines the main challenges and strategies associated with three distinct types of ramp-up processes identified across different products and disruption stages. It also highlights key indicators and enablers that support the effectiveness of ramp-up efforts and the development of supply chain resilience.
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Célestine Jeannette Commenge, Anne-Laure Ladier, Valérie Botta-Genoulaz. Indicators for the Sustainability Evaluation of Short Food Supply Chains: A Systematic Literature Review. 11th IFAC Conference on Manufacturing Modelling, Management and Control, International Federation of Automatic Control, Jun 2025, Trondheim, Norway. pp.280-285, ⟨10.1016/j.ifacol.2025.09.049⟩. ⟨hal-05176316v2⟩
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Short food supply chains have increasingly appeared as sustainable alternatives to the traditional food system, though their sustainability lacks scientific consensus. This systematic literature review examines the indicators used to evaluate the sustainability of short food supply chains, detailed through the ``Sustainability Assessment of Food and Agriculture systems'' framework. The analysis reveals a focus on quantitative evaluations, mainly in occidental countries, with an emphasis on farmers and supply chain configurations with maximum one intermediary. The economic and environmental pillars are the most assessed ones while some social themes are less studied. This review highlights the need to suggest a comprehensive indicator framework tailored to the needs and constraints of the stakeholders of short food supply chains.
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https://hal.science/hal-05176316/file/1-s2.0-S2405896325008109-main.pdf BibTex
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Akram Badreddine Laissaoui, Taha Arbaoui, Anne-Laure Ladier, Khaled Hadj-Hamou. Évaluation dirigée par les données des risques et opportunités pour la planification industrielle et commerciale dans l’industrie automobile. 3ème Congrès Annuel de la SAGIP, Société d'Automatique de Génie Industriel & de Productique, May 2025, Mulhouse, France. ⟨hal-05405678⟩
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Paula Sofia Castro Acevedo, Yenny A. Paredes-Astudillo, Lorraine Trilling, Anne-Laure Ladier. Optimisation de la chaîne d'approvisionnement pour la montée en charge d'un système de production d'épurateurs de biogaz. SAGIP 2025 – 3ème Congrès Annuel, Société d’Automatique, de Génie Industriel & de Productique SAGIP, May 2025, Mulhouse (FR), France. ⟨hal-05351395⟩
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La diversification des sources énergétiques en Europe est devenue une nécessité stratégique, notamment en raison de la diminution des importations de gaz liée à la situation géopolitique actuelle [2]. Dans ce contexte, le biogaz constitue une alternative durable au gaz naturel. Issu de la fermentation anaérobie des déchets organiques dans un digesteur, le biogaz est un mélange gazeux principalement composé de méthane. Son épuration permet d’obtenir du biométhane, un gaz aux propriétés comparables à celles du gaz naturel, pouvant être injecté dans le réseau de distribution ou utilisé comme carburant. Bien que le biométhane constitue une source d’énergie permettant de répondre aux besoins croissants en gaz en Europe, la mise en place des infrastructures d’épuration nécessaires à sa production demeure un processus intrinsèquement complexe, long et coûteux. Ce processus requiert le déploiement d’une structure multi-niveaux, issue de l’ensemble des activités spécialisées impliquées dans la conception, la production et l’installation de ces plateformes. Ces caractéristiques accentuent la complexité de la gestion des flux de matières et d’informations, tout en augmentant la vulnérabilité du système. Dans ce cadre, nous développons une approche de modélisation et d’optimisation de la chaîne d’approvisionnement pour la fabrication et l’assemblage des épurateurs de biogaz afin de garantir la capacité du système à absorber l’augmentation de la demande grâce au concept de montée en cadence (ramp-up) de la chaîne d’approvisionnement, tout en assurant sa résilience face aux fluctuations du marché et aux perturbations potentielles. Ce travail s’appuie sur l’étude d’un cas spécifique d’une chaîne d’approvisionnement située dans la vallée du Rhône, en France.
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https://hal.science/hal-05351395/file/SAGIP_2025_Optimisation_de_la_chaine_d_approvisionnement_pour_la_montee_en_charge_d_un_systeme_de_production_d_epurateurs_de_biogaz_1.pdf BibTex
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Célestine Jeannette Commenge, Anne-Laure Ladier, Valérie Botta-Genoulaz. Overview of main topics and potentials for future research in the short food supply chains. 2ème Congrès Annuel de la SAGIP, Société d'Automatique de Génie Industriel & de Productique, May 2024, Villeurbanne (France), France. ⟨hal-05249624⟩
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https://hal.science/hal-05249624/file/SAGIP_2024.pdf BibTex
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Olivier Briant, Hadrien Cambazard, Nicolas Catusse, Diego Cattaruzza, Maxime Ogier, et al.. Lower bounds for the joint batching, routing and sequencing problem. 37th annual conference of the Belgian Operational Research Society (ORBEL37), May 2023, Liège, Belgium. ⟨hal-04391089⟩
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https://hal.science/hal-04391089/file/orbel37abs.pdf BibTex
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Olivier Briant, Hadrien Cambazard, Diego Cattaruzza, Nicolas Catusse, Anne-Laure Ladier, et al.. A bin-packing formulation for the joint order batching, picker routing and picker sequencing problem. EURO 2022 - 32nd Conference of the Association of European Operational Research Societies, Jul 2022, Espoo, Finland. ⟨hal-03772755⟩
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Picking is the process of retrieving products from inventory. It is considered the most expensive of warehouse operations. To reduce the picking cost, customer orders can be grouped into batches that are then collected by pickers who travel the shortest possible distance.A column generation heuristic able to produce lower and upper bounds for the joint batching and routing problem was proposed in the literature. We show that the methodology can be extended to include the sequencing question, i.e. the additional assignment and sequencing of batches for each picker in order to meet the deadlines of the orders. This aspect is currently seen as a scheduling problem in the literature. We take a different view-point and propose a bin-packing formulation. As a result, the time aspect of the problem is considered indirectly with a drastical decrease of the number of needed variables. Moreover, we benefit from a strong family of cutting planes identified for packing problems and known as dual feasible functions. A stronger lower bound of the integrated problem can be therefore derived by adding such cuts in the formulation proposed for the joint batching and routing problem. Additionally, the bin-packing view-point provide new insights to design efficient heuristics.Optimal solutions are obtained in few seconds for small size instances with thousand of feasible batches. We also provide some results for larger instances with a column generation procedure.
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Fayçal Touzout, Anne-Laure Ladier, Khaled Hadj-Hamou. An assignment-and-routing decomposition matheuristic for the time-dependent Inventory Routing Problem. 23ème Congrès annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF 2022), INSA Lyon, Feb 2022, Villeurbanne - Lyon, France. ⟨hal-03595238⟩
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The inventory routing problem (IRP) integrates two operational problems of the supply chain: inventory management and routing. The objective of the decision-maker is to decide, for each period of the time horizon, whether a client should be replenished, with which quantity and following which route, optimising both the inventory and transportation costs.When evolving in an urban logistics context, one problem that can be faced is the volatility of the travelling times between locations. This volatility is represented in this paper by considering the travelling times as time dependent. As time-dependent problems tend to be harder to solve than their basic counterpart \cite{Gendreau2015}, it is necessary to propose new efficient algorithms. In this paper, a matheuristic that decomposes the problem into first assigning the clients to visit at each period and then solving a time-dependent travelling salesman problem (TD-TSP) is proposed.
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https://hal.science/hal-03595238/file/Papier.pdf BibTex
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Maximilian Zimmermann, Fayçal A. Touzout, Anne-Laure Ladier, Khaled Hadj-Hamou. Deterministic construction heuristics for the time-dependent travelling salesman problem. 23ème Congrès annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF 2022), INSA Lyon, Feb 2022, Villeurbanne - Lyon, France. ⟨hal-03595274⟩
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The time-dependent travelling salesman problem (TD-TSP) extends the TSP by considering the travel time between two locations as time-dependent. As the TD-TSP is NP-hard, it is difficult to find an optimal solution for large-sized instances. In this case, construction heuristics provide fast and easy to implement solutions. Such solutions can be used in real-world situations where optimality is not necessary. Furthermore, they can be used for improvement heuristics as initial solutions. Although construction heuristics are commonly used for the TSP, only few of them are adapted to the TD-TSP. This thesis adapts and evaluates five of the most prominent construction algorithms of the TSP to the TD-TSP: Cheapest Insertion, Christofides, First Fit, Nearest Neighbour and Savings. In order to compare the performances of the considered heuristics, numerical experiments are performed on one artificial and two real-life based time-dependent benchmarks. The results of the comparison are validated on TSP instances from the literature. The outcomes show that the modified Savings algorithm outperforms all other approaches significantly.
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https://hal.science/hal-03595274/file/Abstract_Conference.pdf BibTex
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Anne-Laure Ladier, Lorraine Trilling. Modélisation et évaluation des chaînes logistiques résilientes. 23ème Congrès annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF 2022), INSA Lyon, Feb 2022, Villeurbanne - Lyon, France. ⟨hal-03595338⟩
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https://hal.science/hal-03595338/file/CIRPe2021.pdf BibTex
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Lauriane Bret, Maxime Dussud, Lucas Metral, Anne-Laure Ladier, Lorraine Trilling. Towards a model assessing supply chain resilience strategies. 9th Global Web Conference (CIRP 2021), Oct 2021, Saint Etienne, France. pp.14-19, ⟨10.1016/j.procir.2021.10.001⟩. ⟨hal-03419962⟩
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The ongoing pandemics has shown that the resilience of our global supply chains can be strengthened. Several mitigation strategies can be put in place in order to respond to major disruptions, but assessing their performance is still a challenge. This article proposes a review of possible disruptions and the main drivers to improve the SC resilience. This leads us to propose a list of risk mitigation strategies that could be adopted to prevent or react to disruptions, and a list of resilience indicators. Finally, a methodology is proposed to assess different mitigation strategies under comprehensive disruptions scenarios, regarding various resilience indicators.
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https://hal.science/hal-03419962/file/1-s2.0-S2212827121008428-main.pdf BibTex
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Corentin Le Hesran, Anne-Laure Ladier, Valérie Botta-Genoulaz. Multi-objective Genetic Algorithm to Reduce Setup Waste in a Single Machine with Coupled-Tasks Scheduling Problem. IFIP International Conference on Advances in Production Management Systems (APMS 2021), Sep 2021, Nantes, France. pp.399-408, ⟨10.1007/978-3-030-85874-2_42⟩. ⟨hal-03351276⟩
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This article studies a single-machine scheduling problem involving coupled-tasks and hard due dates. A genetic algorithm based on the Non-dominated Sorting Genetic Algorithm (NSGA) II model is proposed to carry out a bi-objective optimization of both holding cost and setup-related waste generation. Results show that the multi-objective genetic algorithm outperforms the previous approaches regarding both computation time and objective functions, showing that a reduction of setups of 36% is possible at the expense of an 11% increase in inventory with acceptable computation times. It also highlights the importance of multi-objective optimization for decision-making in case of conflicting objective functions.
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https://hal.science/hal-03351276/file/509923_1_En_42_Chapter.pdf BibTex
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Faycal Touzout, Anne-Laure Ladier, Khaled Hadj-Hamou. Time-dependent travel-time constrained Inventory Routing Problem. International Conference of Computational Logistics, Sep 2020, Enschede (virtual conference), Netherlands. pp 151-166, ⟨10.1007/978-3-030-59747-4_10⟩. ⟨hal-02955305⟩
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The Inventory Routing Problem (IRP) is an integration of two operational problems: inventory management and routing. The Time-Dependent Travel-Time Constrained (TD-TC-IRP) is a new proposed variant of the IRP where the travelling time between two locations depend on the time of departure throughout the day and the length of a trip is time-constrained. The real-world discontinuous time-dependent data that we use will be modelled by a piece-wise linear continuous function. A mathematical formulation for the TD-TC-IRP is proposed, to emulate such transformation. Numerical experiments are conducted, to validate the mathematical formulation, on a new benchmark combining benchmarks from the IRP and time-dependent routing problems literature .
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https://hal.science/hal-02955305/file/Paper.pdf BibTex
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Faycal Touzout, Anne-Laure Ladier, Khaled Hadj-Hamou. Inventory Routing Problem : ré-optimisation sous incertitudes. 21ème Congrès annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF 2020), Feb 2020, Montpellier, France. ⟨hal-02900785⟩
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https://hal.science/hal-02900785/file/ROADEF2020.pdf BibTex
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Olivier Briant, Hadrien Cambazard, Diego Cattaruzza, Nicolas Catusse, Anne-Laure Ladier, et al.. A column generation approach for the joint order batching and picker routing problem. Workshop of the EURO Working Group on Vehicle Routing and Logistics optimization (VeRoLog 2019), Jun 2019, Seville, Spain. ⟨hal-02317032⟩
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Picking is the process of retrieving products from inventory.It is mostly done manually by dedicated employees called pickers and is considered the most expensive of warehouse operations.To reduce the picking cost, customer orders can be grouped into batches that are then collected by traveling the shortest possible distance.This work presents an exponential linear programming formulation to tackle the joint order batching and picker routing problem.Variables, or columns, are related to the picking routes in the warehouse.Computing such routess is generally an intractable routing problem and relates to the well known traveling salesman problem (TSP).Nonetheless, the rectangular warehouse's layouts can be used to efficiently solve the corresponding TSP and take into account in the development of an efficient subroutine, called oracle.We therefore investigate whether such an oracle allows for an effective exponential formulation.In order to tackle the exponential number of variables, we develop a column generation heuristic with performance guarantee.The pricing problem approximates the distances, and when finding a solution the oracle is used to get the optimal distance of this solution.The performance of the proposed column generation is strengthen using stabilization techniques and a rich column set.Experimented on a publicly available benchmark, the algorithm proves to be very effective.It improves many of the best known solutions and provides very strong lower bounds.Finally, this approach is applied to another industrial case to demonstrate its interest for this field of application.
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Corentin Le Hesran, Anne-Laure Ladier, Valérie Laforest, Valerie Botta-Genoulaz. Using flow assessment to identify a scheduling problem with waste reduction concerns: a case study. 6th International EurOMA Sustainable Operations and Supply Chains Forum, Mar 2019, Göteborg, Sweden. ⟨hal-02147307⟩
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This paper proposes a first insight on how flow assessment can support the identification and modeling of waste-minimizing shop-floor scheduling problems. Using relevant elements from existing flow assessment methods, a four-step methodology is devised. After an overview of the different steps, a case study of hubcap manufacturing is conducted. The outcome of this case study is an identified scheduling problem with clearly defined constraints, objectives and parameters. The economic and environmental impacts are both quantified, and decision variables for problem solving are provided.
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https://hal.science/hal-02147307/file/Le%20Hesran%20et%20al.%20-%202019%20-%20Using%20flow%20assessment%20to%20identify%20a%20scheduling%20problem%20with%20waste%20reduction%20concerns%20a%20case%20study.pdf BibTex
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Bérangère Clere Andre, Giannina Dottavio, Luc Espagnon, Vincent Cheutet, Anne-Laure Ladier, et al.. Optimized decommissioning management by an innovative decision-making tool. 1st International Nuclear Digital Experience (INDEX 2018), Jun 2018, Paris, France. ⟨hal-01847838⟩
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With the increase in number of nuclear power plants shutdown, nuclear decommissioning activities are in worldwide expansion. Decommissioning operations mobilize a lot of technological equipment and high-skilled workers over long periods, and generate complex physical flows of waste. We propose to improve decommissioning management efficiency by developing an innovative decision-making tool
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Corentin Le Hesran, Anne-Laure Ladier, Valerie Botta-Genoulaz, Valérie Laforest. Reducing waste in manufacturing operations: a mixed integer linear program for bi-objective scheduling on a single-machine with coupled-tasks. 16th IFAC Symposium on Information Control Problems in Manufacturing (INCOM 2018), Jun 2018, Bergamo, Italy. pp.1695 - 1700, ⟨10.1016/j.ifacol.2018.08.212⟩. ⟨emse-01875282⟩
resume
This study addresses a scheduling problem involving a single-machine with coupled-tasks and bi-objective optimization considering simultaneously inventory and environmental waste-related costs. A mixed integer linear program representing the problem is developed and experimented on with multiple instances. The Pareto front is determined using the ε-constraint method, and a trade-off point is selected according to a distance criterion. The results show that a compromise can be found between an increased inventory and a reduction of waste generation. Moreover, developing new methods for solving problems of larger scale would benefit industrial decision-makers and sustainable production research.
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Marion Roux-Sablier, Anne-Laure Ladier, Samuel Vercraene Vercraene, Thomas Bontems. Planification des opérations de ballastage pour la maintenance des voies ferrées. 19ème Congrès annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF 2018), Feb 2018, Lorient, France. ⟨hal-01765077⟩
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https://hal.science/hal-01765077/file/ROADEF2018_paper_049.pdf BibTex
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Olivier Briant, Hadrien Cambazard, Diego Cattaruzza, Nicolas Catusse, Anne-Laure Ladier, et al.. A column generation based approach for the joint order batching and picker routing problem. 19ème Congrès annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF 2018), Feb 2018, Lorient, France. pp.1-2. ⟨hal-01765113⟩
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https://hal.science/hal-01765113/file/ROADEF2018_paper_060.pdf BibTex
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Corentin Le Hesran, Valérie Botta-Genoulaz, Valérie Laforest, Anne-Laure Ladier. Réduire les déchets de production : ordonnancement bi-objectif sur une machine unique avec réentrance. 24ème journées Sciences et Techniques de la Production du GdR MACS (STP 2017), Nov 2017, Nancy, France. ⟨emse-01633457⟩
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Nos travaux s'inscrivent dans le cadre de la production durable, et s'intéressent aux moyens de réduire les déchets générés par les changements de série grâce à un ordonnancement adapté. Dans cette présentation, on s'intéresse au problème de l'ordonnancement d'un ensemble de tâches couplées sur une machine unique. Chaque tâche est composée de plusieurs opérations (qui peuvent être de nature différente) avec, le cas échéant, un temps inter-opératoire minimum entre les opérations d'une même tâche, et des dates d'échéance qui doivent être respectées. Il s'agit d'un problème d'optimisation bi-objectif cherchant à minimiser l'avance des tâches sur leur date d'échéance (minimisation des coûts d'immobilisation) ainsi que le nombre total de changements de série entre deux opérations consécutives (minimisation des processus générant des déchets, et donc du coût de leur traitement). Le problème est modélisé en programmation linéaire à variables mixtes. On cherche à montrer qu'il est possible de réduire les déchets sans dégrader les indicateurs économiques, afin de faciliter la prise de décision des gestionnaires de production.
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Giannina Dottavio, M. F. Andrade, Frédéric Renard, Vincent Cheutet, Anne-Laure Ladier, et al.. Logistical Optimization of Nuclear Waste Flows during Decommissioning. 8th International Conference on Energy Management (ICEM 2016), Oct 2016, Paris, France. ⟨hal-01408799⟩
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Daniel Diekmann, Uwe Clausen, Lars Eufinger, Gülgün Alpan, Anne-Laure Ladier. Combining mathmatical optimization and discrete-event simulation to improve cross-docking operations. International Conference on Operations Research (OR 2016), Aug 2016, Hamburg, Germany. ⟨hal-01367336⟩
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Anne-Laure Ladier, Samuel Vercraene Vercraene, Vincent Cheutet, Rémi Dachicourt. Planification et gestion des flux de déchets issus du démantèlement d'installations nucléaires. 17ème Congrès annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF 2016), Feb 2016, Compiègne, France. ⟨hal-04496074⟩
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https://hal.science/hal-04496074/file/Ladier_Vercraene_Cheutet_Dachicourt_ROADEF2016.pdf BibTex
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Anne-Laure Ladier, Allen G. Greenwood, Gülgün Alpan. Modeling issues when using simulation to test the performance of mathematical programming models under stochastic conditions. 29th IEEE European simulation and modelling conference (ESM 2015), Oct 2015, Leicester, United Kingdom. pp.117-121. ⟨hal-01222837⟩
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Discrete-event simulation (DES) models and discrete mathematical-programming optimization (DMPO) models are often used together in a variety of ways. This paper discusses the issues that modelers must address when using DES models to test the performance of DMPO models in a stochastic environment. The issues arise during validation of the simulation models – comparing the simulation results under deterministic conditions with results from deterministic optimization models. In our case, the issues are derived from validating simulation models that are used to test the performance of scheduling and resource allocation models (integer and mixed-integer programming optimization models) under various types of uncertainty. The models are from our work in crossdocking operations; however, we believe they are relevant to a wide variety of problem domains. In addition to describing the issues, we offer suggestions on how modelers might address the concerns.
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https://hal.science/hal-01222837/file/LadierEurosis_submission.pdf BibTex
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Anne-Laure Ladier, Gülgün Alpan. Integrating truck scheduling and employee rostering in a cross-docking platform – an iterative approach. International Conference on Industrial Engineering and Systems Management, Oct 2015, Séville, Spain. ⟨hal-01222838⟩
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In a crossdocking platform, goods are unloaded, transferred and reloaded into trucks with little or no storage in between. The crossdock truck scheduling problem addresses the hard problem of coordinating the truck operations. However, crossdock operations are mostly done manually: it is therefore important to take staffing issues into account while building the truck schedule. This article shows how a truck scheduling model and an employee timetabling and rostering model can be combined to address both problems in an integrated manner. Three approaches are compared. The sequential approach consists in sequentially solving the two problems: from the truck schedule calculated first, a workload is deduced and used as input for the employee timetabling and rostering process. The iterative approach, inspired by Weide et al. (2010), consists in solving both problems one after another in an iterative manner until a stable point is reached. Two iterative procedures are proposed, employees-first and trucks-first.
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Anne-Laure Ladier, Gülgün Alpan. Planification intégrée des camions et des employés dans une platforme de cross-docking. Congrès annuel de la société française de recherche opérationnelle et d’aide à la décision (ROADEF), Feb 2015, Marseille, France. ⟨hal-01222840⟩
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Quentin Christ, Anne-Laure Ladier, Bernard Penz. Ordonnancement d’atelier sous contrainte de ressources : cas d’application dans l’industrie chimique. Roadef ( Société Française de Recherche Opérationnelle et d'Aide à la Décision) 2015, Feb 2015, Marseille, France. ⟨hal-01178658⟩
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https://hal.science/hal-01178658/file/Christ2015-ROADEF.pdf BibTex
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Anne-Laure Ladier, Gülgün Alpan, Allen G. Greenwood. Robustness evaluation of an IP-based cross-docking schedule using discrete-event simulation. Industrial and Systems Engineering Research Conference, Jun 2014, Montréal, Canada. pp.I211. ⟨hal-01062156⟩
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Integer programming (IP) models are powerful tools for operations planning, but may encounter problems when applied in a stochastic environment. We propose a methodology to evaluate the robustness of an IP model using discrete-event simulation. In our case, the IP model determines truck and pallet schedules for a cross-docking facility. A portion of the output from the IP model is used as input to a simulation model that represents the facility. The decisions regarding pallet transfers and truck departures are left to the simulation model to ensure flexibility. Random events are induced through the simulation in order to see how robust the IP-based schedules are against the uncertainties in: (i) the transfer time of pallets through the cross-dock, (ii) the unloading time of pallets from trucks, and (iii) the earliness or delay of the trucks arriving at the platform. The difference between the deterministic and the stochastic scenarios are evaluated regarding the number of pallets put into storage, truck docking and sojourn times. Robustness measures are proposed based on numerical experiments.
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Anne-Laure Ladier, Gülgün Alpan. Planification des opérations de cross-docking. ROADEF - 15ème congrès annuel de la Société française de recherche opérationnelle et d'aide à la décision, Société française de recherche opérationnelle et d'aide à la décision, Feb 2014, Bordeaux, France. ⟨hal-00946441⟩
resume
Les plateformes de cross-docking permettent d'accélérer les flux logistiques : les produits y sont déchargés, triés et rechargés dans les camions sans stockage intermédiaire. Nous nous intéressons à un problème de planification des opérations dans une telle plateforme, en supposant que les transporteurs communiquent à l'avance leurs créneaux de présence préférés. Outre la modélisation du problème par un programme linéaire, nous proposons deux heuristiques qui décomposent le problème et permettent ainsi de traiter des instances de taille plus réaliste [1].

La robustesse du modèle est évaluée avec un modèle de simulation qui soumet le planning à des événements imprévus [2]. L'objectif est maintenant de proposer des reformulations plus robustes du modèle initial. Nous retenons en particulier trois techniques non encore étudiées dans le cas du cross-docking: les méthodes génériques d'optimisation robustes, et les méthodes plus spécifiques, empruntées à la planification de projet, de redondance temporelle et de redondance de ressources. Tester et évaluer la robustesse de chaque variante à l'aide du modèle de simulation permet de réaliser une analyse comparée des différentes techniques.

Ce modèle de planification des opérations sera ensuite couplé au modèle de planification des employés décrit en [3], afin de proposer un modèle intégré de pilotage des opérations de la plateforme.

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https://hal.science/hal-00946441/file/LADIER_resume_Jeune_chercheur.pdf BibTex
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Anne-Laure Ladier, Gülgün Alpan. Scheduling truck arrivals and departures in a cross dock: earliness, tardiness and storage policies. International Conference on Industrial Engineering and Systems Management, Oct 2013, Rabat, Morocco. pp.711-717. ⟨hal-00946531⟩
resume
This article proposes a model to simultaneously plan truck arrivals, truck departures and internal pallet handling in a crossdocking platform. The objective is to minimize both the total number of pallets put in storage on the planning horizon, and the dissatisfaction of the transportation providers, by creating a truck schedule as close as possible to the wished schedule they communicate in advance. The problem is modeled with an integer program, which is tested on generated instances to assess its performances, especially regarding the computation time. Since the execution takes too long to be used by platform managers on a daily basis, two heuristics are also proposed and tested. We show in which conditions each heuristic performs best, which can help in choosing a solution method when confronted to a real-life problem.
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Anne-Laure Ladier, Allen G. Greenwood, Gülgün Alpan, Halston Hales. Simulation-based assessment of the robustness of IP-based truck schedules for cross-docking operations. 26th European Conference on Operation Research, Jul 2013, Rome, Italy. ⟨hal-00859897⟩
resume
A previously developed IP-based model for scheduling truck arrivals, truck departures, and pallet handling in a cross-docking platform is assessed using discrete-event simulation. Experimentation with a simulation model of basic cross-docking operations subjects the schedules to a more realistic environment (e.g., stochastic truck arrival times, pallets transfer times, truck content) than can be formulated in the IP model. Analysis of the simulation experiments, in terms of the schedules' performance and robustness under pragmatic conditions, provides insights to help refine the IP model.
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Allen G. Greenwood, Halston Hales, Gülgün Alpan, Anne-Laure Ladier. Performance evaluation of worker timetables in cross-docking facilities using simulation. 26th European Conference on Operation Research, Jul 2013, Rome, Italy. ⟨hal-00966688⟩
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Anne-Laure Ladier, Allen G. Greenwood, Gülgün Alpan. Cross docking operations: a simulation model for the validation and robustness assessment of IP - based truck schedules. Analytics Research Workshop, Deep South INFORMS Regional Chapter, Apr 2013, Tuscaloosa, AL, United States. ⟨hal-00859932⟩
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In cross-docking facilities, goods are unloaded from incoming trucks, sorted, and reloaded within 24 hours onto outbound trucks based on their destination. In an earlier work [1], we proposed an IP-based model for truck scheduling that is based on dock reservation and storage policies. The resulting schedule both maximizes the transportation providers' satisfaction and minimizes the number of items temporarily stored. While IP models cannot consider many detailed operational aspects of the cross-docking facility, discrete-event simulation models can represent systems closer to real-life situations. Therefore, in this research, we use a simulation model to assess the performance and robustness of the IP model and its resulting schedule. In the validation phase, we check that the assumptions made for the IP model are not too restrictive by determining their validity range. In a second phase, stochastic events are introduced in the simulation model to assess the robustness of an IP-generated schedule. As such, we address such questions as, does the proposed schedule still perform well (with minor modifications) when a truck arrives late, or if the content of a truck is different than expected? The insights gathered will be used to refine the IP model formulation to increase its robustness.
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Anne-Laure Ladier, Gülgün Alpan, Bernard Penz. Optimisation séquentielle des emplois du temps dans une plateforme logistique. Roadef 2011, Mar 2011, Saint-Etienne, France. pp.CD-rom. ⟨hal-00671683⟩
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HDR

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Anne-Laure Ladier. Réduire les déchets, mutualiser les flux : planification et ordonnancement pour une écologie industrielle. Modélisation et simulation. Institut National des Sciences Appliquées de Lyon (INSA Lyon); Université Claude Bernard Lyon 1, 2024. ⟨tel-04980040⟩
resume
Trois familles de problèmes d’aide à la décision sont adressés dans différents domaines d’applications industrielles. La première traite de la planification et l’ordonnancement pour la gestion des déchets, visant à déterminer une organisation efficace sous contrainte de ressources. Les travaux portent sur les déchets industriels dangereux et sur les déchets issus du démantèlement nucléaire. La deuxième famille de problèmes est la mutualisation des flux logistiques pour réduire l’impact du transport. L’optimisation du transbordement et la réduction des distances parcourues dans des tournées de véhicules sont des problèmes qui cherchent une organisation efficace dans l’espace en exploitant des structures de réseau. Les travaux incluent l’automatisation des plateformes de transbordement prenant en compte leur consommation d’énergie, et l’efficience de la préparation de commandes dans des plateformes traditionnelles peu automatisées. De plus, des recherches sont menées sur l’incertitude des demandes et des temps de trajet dans le cadre du transport de marchandises en ville, dans le cadre du problème d’inventory routing et avec des flottes de véhicules hétérogènes en termes de vecteurs énergétiques et de capacités. Enfin, les problèmes de maintenance des voies ferrées relient les deux domaines précédents en déterminant une organisation dans le temps sous contrainte de ressource, tout en exploitant une structure de réseau. L’objectif est de trouver une organisation temporelle sous contrainte de ressources en exploitant la structure de réseau. Des modèles d’aide à la décision sont proposés pour organiser l’entretien du ballast et de la végétation aux abords des voies. Ces travaux de maintenance, effectués par des engins passant sur les voies, doivent être planifiés en tenant compte de la disponibilité des voies. Les problèmes étudiés partagent des caractéristiques communes, notamment l’aspect multicritère de la décision et la gestion de l’incertitude. Ces aspects sont importants tant dans l’ordonnancement de production pour générer moins de déchets industriels dangereux que dans la planification de la maintenance des voies ferrées, tous deux en lien avec des problématiques environnementales. L’intégration de l’analyse du cycle de vie permet de déterminer quels problèmes d’ordonnancement permettent de réduire les déchets et de dimensionner des flottes de véhicules hétérogènes pour la livraison urbaine. Les approches de résolution utilisées incluent la programmation linéaire, la programmation linéaire en nombres entiers, le couplage optimisation-simulation, le développement de matheuristiques dédiées et des métaheuristiques.
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Rapport

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Anne-Laure Ladier, Allen G. Greenwood, Gülgün Alpan, Halston Hales. Issues in the complementary use of simulation and optimization modeling. [Research Report] --. 2014. ⟨hal-00946541⟩
resume
Simulation models and discrete optimization models are oftentimes used together in a variety of ways. In this paper, we discuss the issues that modelers must address in cases where simulation models are used to test a discrete mathematical programming optimization model's performance in a stochastic environment. The issues arise during validation of simulation models, when checking agreement between deterministic optimization results and simulation models operating under deterministic conditions. In our case, the issues are derived from validating simulation models that are used to test the performance of scheduling and resource allocation models (integer and mixed-integer programming optimization models) under various types of uncertainty. While the concerns we describe are from our work in the logistics domain (cross-docking operations), they are relevant to a wide variety of problem domains. In addition to describing the issues, we offer suggestions on how modelers might address the concerns.
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Thèse

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Anne-Laure Ladier. Scheduling cross-docking operations : Integration of operational uncertainties and resource capacities. Automatic. Université de Grenoble, 2014. English. ⟨NNT : 2014GRENI066⟩. ⟨tel-01126878⟩
resume
Dans une plateforme de cross-docking, les produits sont déchargés descamions entrants, triés puis directement rechargés dans les camions sortants– chaque produit passe moins de 24 heures sur la plateforme.L’analyse des écarts entre la littérature et les observations réalisées sur leterrain permet de dégager deux axes de recherche : la prise en compte desincertitudes opérationnelles d’une part, et de la capacité des ressourceshumaines de la plateforme d’autre part.Le problème de planification des camions entrants et sortants avec fenêtrede temps est modélisé par un programme linéaire et résolu par troisheuristiques différentes. La robustesse des plannings obtenus est ensuitetestée à l’aide d’un modèle de simulation à événements discrets, qui permetd’évaluer plusieurs reformulations robustes du modèle initial.Le problème de planification des employés sur la plateforme est traité àl’aide de trois programmes linéaires mixtes, résolus de façon séquentielle.La combinaison des deux modèles permet d’obtenir un modèle d’aide àla décision pour une plateforme de cross-docking.
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https://theses.hal.science/tel-01126878/file/2014GRENI066.pdf BibTex

Pré-publication, Document de travail

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Olivier Briant, Hadrien Cambazard, Diego Cattaruzza, Nicolas Catusse, Anne-Laure Ladier, et al.. A bin packing formulation for the joint batching, routing and sequencing problem. 2023. ⟨hal-04052967v3⟩
resume
Warehouses are the scene of complex logistic problems integrating different decision layers. This paper addresses the Joint Order Batching, Picker Routing and Sequencing Problem with Deadlines (JOBPRSP-D) in rectangular warehouses. To tackle the problem, an exponential linear programming formulation related to bin packing is proposed. It is solved with a column generation heuristic able to provide lower and upper bounds on the optimal value. We start by showing that the JOBPRSP-D is related to a bin packing problem as opposed to a scheduling problem. We take advantage of this aspect to derive a number of valid inequalities that enhance the resolution of the master problem. The proposed algorithm is evaluated on publicly available data-sets. It is able to optimally solve instances with up to 18 orders in a few minutes. It is also able to prove optimality or to provide high-quality lower bounds on larger instances with 100 orders as long as the picker's capacity is small enough. Finally, new upper bounds are found on all the instances except two of the benchmark considered. To the best of our knowledge this is the first article that provides optimality guarantee on large size instances for the JOBPRSP-D; the results can therefore be used to assert the quality of heuristics proposed for the same problem.
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https://hal.science/hal-04052967/file/A%20bin%20packing%20formulation%20for%20the%20joint%20batching%2C%20routing%20and%20sequencing%20problem.pdf BibTex