A MODELLING FRAMEWORK FOR PROCUREMENT OF A RETAIL DISTRIBUTION SYSTEM WITH ECONOMIC AND ENVIRONMENTAL GOALS

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A state of the art and a general formulation model of Hub Location-Routing Problems for LTL shipments

National audienceIn many logistic systems for less than truckload (LTL) shipments, transportation of goods from one origin to its destination is made through collection tours to a hub and delivery tours from the same or another hub, while the goods are shipped between two hubs using Full Truckload (FTL) shipments. Therefore, managers need to determine the location of the hubs, the allocation of non-hub nodes, and the optimal collection and delivery routes within the network. This problem, known as the hub location-routing problem (HLRP), is related to both the hub location problem (HLP) and the location-routing problem (LRP). The HLP involves the location of hub facilities concentrating flows in order to take advantage of economies of scale and through which flows are to be routed from origins to destinations. The objective of the HLRP is to minimize the total costs including hub costs, inter-hub transportation costs, and collection/distribution routing costs. Based on the literatures review, the aims of this paper are to analyze the state of the art, propose some generic mathematical models for the HLRP and implement some tests using a MIP solver

An adaptive large neighborhood search for a full truckload routing problem in public works

International audienceThis paper presents a truck routing and scheduling problem faced by a public works company. Itconsists of optimizing the collection and delivery of materials between sites, using a heterogeneousfleet of vehicles. These flows of materials arise in levelling works and construction of roads networks.As the quantity of demands usually exceeds the capacity of a truck, several trucks are needed tofulfill them. As a result, demands are split into full truckloads. A set of trucks routes are needed toserve a set of demands sharing a set of resources, available at pickup or delivery sites, which can beloaders or asphalt finishers in our application cases. Thus, these routes need to be synchronized ateach resource. We propose an Adaptive Large Neighborhood Search (ALNS) to solve this problem.This approach is evaluated on real instances from a public work company in France

Modélisation et résolution de problèmes généralisés de tournées de véhicules

Le problème de tournées de véhicules est un des problèmes d optimisation combinatoire les plus connus et les plus difficiles. Il s agit de déterminer les tournées optimales pour une flotte de véhicules afin de servir un ensemble donné de clients. Dans les problèmes classiques de transport, chaque client est normalement servi à partir d un seul nœud (ou arc). Pour cela, on définit toujours un ensemble donné de nœuds (ou arcs) obligatoires à visiter ou traverser, et on recherche la solution à partir de cet ensemble de nœuds (ou arcs). Mais dans plusieurs applications réelles où un client peut être servi à partir de plus d un nœud, (ou arc), les problèmes généralisés qui en résultent sont plus complexes. Le but principal de cette thèse est d étudier trois problèmes généralisés de tournées de véhicules. Le premier problème de la tournée sur arcs suffisamment proche (CEARP), comporte une application réelle intéressante en routage pour le relevé des compteurs à distance ; les deux autres problèmes, problème de tournées couvrantes multi-véhicules (mCTP) et problème généralisé de tournées sur nœuds (GVRP), permettent de modéliser des problèmes de conception des réseaux de transport à deux niveaux. Pour résoudre ces problèmes, nous proposons une approche exacte ainsi que des métaheuristiques. Pour développer la méthode exacte, nous formulons chaque problème comme un programme mathématique, puis nous construisons des algorithmes de type branchement et coupes. Les métaheuristiques sont basées sur le ELS (ou Evolutionary Local Search) et sur le GRASP (ou Greedy Randomized Adaptive Search Procedure). De nombreuses expérimentations montrent la performance de nos méthodes.The Routing Problem is one of the most popular and challenging combinatorial optimization problems. It involves finding the optimal set of routes for fleet of vehicles in order to serve a given set of customers. In the classic transportation problems, each customer is normally served by only one node (or arc). Therefore, there is always a given set of required nodes (or arcs) that have to be visited or traversed, and we just need to find the solution from this set of nodes (or arcs). But in many real applications where a customer can be served by from more than one node (or arc), the generalized resulting problems are more complex. The primary goal of this thesis is to study three generalized routing problems. The first one, the Close-Enough Arc Routing Problem(CEARP), has an interesting real-life application to routing for meter reading while the others two, the multi-vehicle Covering Tour Problem (mCTP) and the Generalized Vehicle Routing Problem(GVRP), can model problems concerned with the design of bilevel transportation networks. The problems are solved by exact methods as well as metaheuristics. To develop exact methods, we formulate each problem as a mathematical program, and then develop branch-and-cut algorithms. The metaheuristics are based on the evolutionary local search (ELS) method et on the greedy randomized adaptive search procedure (GRASP) method. The extensive computational experiments show the performance of our methods.NANTES-ENS Mines (441092314) / SudocSudocFranceF

A memetic algorithm for the hub location-routing problem

International audienceIn many logistic systems for less than truckload (LTL) shipments, transportation of goods is made through collection/delivery tours to/from a hub. The design of such a logistic network corresponds to the Hub Location Routing Problem (HLRP). HLRP consists in locating hub facilities concentrating flows in order to take advantage of economies of scale and through which flows are to be routed from origins to destinations, and considers also both collection and distribution routes. We present a generic MIP formulation of this problem and a solution method based on a genetic algorithm improved by some local searches. Computational experiments are presented

Lymphadenectomy in women with endometrial cancer: aspiration and reality from a radiation oncologist’s point of view

Background: To investigate the meaning of lymphadenectomy (LNE) in women with endometrial cancer (EC) for clinical outcome and secondly to determine the impact of the method of adjuvant radiotherapy (RT) on survival as well as to define prognostic factors. Methods: 322 patients (pts) underwent adjuvant RT for endometrioid EC at our department from 2004 until 2012 and were included in this retrospective study. Chi-square test, LogRank test and Cox regression were used for statistical analyses. Results: Median age at diagnosis: 66 years. FIGO stages: FIGO I 69.4 %, FIGO II 15.3 %, FIGO III 14.5 %, FIGO IV 0.9 %. Surgical staging: 30.6 % pelvic/paraaortic LNE, 45 % sole pelvic LNE, 8.8 % sampling of suspicious lymph nodes, 15.6 % no LNE. Adjuvant chemotherapy (ChT): 3.2 %. Sole intravaginal brachytherapy (IVB): 60.2 %. IVB + external beam radiotherapy (EBRT): 39.8 %. 5-year local recurrence free survival (LRFS): 90.6 %, distant metastases free survival (DMFS): 89.8 %, overall survival (OS):79.3 %. In multivariate analysis age (p = .007), pT stage (p = .029), lymph node status (p = .003), grading (p = .011) and lymphovascular space invasion (LVSI; p = .008) remained as independent prognostic factors for OS. Resection status (p = .01) and LVSI (p = .014) were independent prognostic factors for LRFS and LVSI (p = .008) was the only independent prognostic factor for DMFS. There was no statistically significant survival benefit from LNE in LRFS (p = .561), DMFS (p = .981) or OS (p = .791). 5-year LRFS in stage I and II: 96.0 and 82.9 % after sole IVB, 90.8 and 81.6 % after combined IVB/EBRT (p = .105; p = .970). 5-year OS rates for stage I and II: 86.5 and 71.3 % after sole IVB, 84.2 % and 69.2 % after combined IVB/EBRT (p = .153; p = .619). Conclusion: Comprehensive surgical staging is rarely performed and may be omitted in women with endometrioid EC in stages I-II. Sole IVB delivers equally good local control as combined IVB/EBRT in pts with FIGO stage I and II disease. LVSI deserves more attention as a prognostic factor and these pts may require a combined local and systemic therapy

Linear accelerator-based stereotactic fractionated photon radiotherapy as an eye-conserving treatment for uveal melanoma

Background: The purpose of this retrospective analysis is to analyze clinical outcome, visual acuity and enucleation rates after linear accelerator-based stereotactic fractionated photon radiotherapy for primary uveal melanoma. Methods: Twenty-four patients with primary uveal melanoma treated at the Department of Radiation and Oncology of the University Hospital Heidelberg between 1991 and 2015 were analyzed regarding survival and treatment-related toxicity including eye- and sight-preservation. Results: Photon radiotherapy (RT) offered good overall local control rates with a local progression-free survival (LPFS) of 82% after 5 years and a median LPFS of 5.5 years at a median follow-up time of 5.2 years. Gender had a significant impact on LPFS yielding a mean LPFS of 8.1 years for women and 8.7 years for men (p = 0.04). Of all local progressions, 80% occurred within the first 5 years after RT. In one case, enucleation as final therapy option was necessary. Enucleation-free survival (EFS) was related to the radiotherapy dose (p < 0.0001). Thus, higher prescribed doses led to a significantly higher enucleation rate. T-stage had no significant impact on EFS, but affected the enucleation rate (p = 0.01). The overall survival (OS) rate was 100% after 2 years and 70% after 5 years with a median OS of 5.75 years. Age (p = 0.046), T stage (p = 0.019), local control rate (p = 0.041) and the time between diagnosis and the first radiation session (p = 0.01) had a significant effect on OS. Applied biologically effective dose (BED) did not significantly influence OS or PFS. A 2-year sight preservation rate of 75% could be achieved. In all patients, irradiation could be applied safely without any interruptions due to side effects. Six significant late toxicities with consequential blindness could be observed, making a secondary enucleation necessary in four patients. An impairment of visual acuity due to chronic optic nerve atrophy was identified in five patients within 2 years after treatment. Conclusions: Linear accelerator-based stereotactic fractionated photon radiotherapy is an effective method in the treatment of uveal melanoma with excellent local control rates and a 2-year vision retention rate comparable to brachytherapy (BRT) or proton beam radiotherapy, even available in small centers and easy to implement. Interdisciplinary decision making is necessary to guarantee best treatment for every patient

L'éolien offshore : une logistique complexe en manque de pilotage

International audienc