54 research outputs found

    Modélisation et conception de boucles d'approvisionnement : contexte multi-produit, multi-état et multi-alternative de traitement :application à un service dans le domaine de la santé

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    Cette thèse propose une méthodologie générique de conception de réseaux logistiques intégrant la logistique inversée à une chaîne régulière d’approvisionnement. Le type de réseaux abordé prévoit la récupération des produits inutilisés des utilisateurs finaux, leur traitement et leur redistribution vers de nouveaux utilisateurs. Suivant leur état, les produits récupérés peuvent être réparés, désassemblés pour la récupération de pièces de rechange ou ultimement être disposés. Les produits réutilisables obtenus suite au traitement sont désignés comme des produits valorisés. Ils représentent une source économique d’approvisionnement, mais dont le standard de qualité est inférieur à ceux offerts à l’état neuf. L’objectif de la méthodologie est de supporter les décisions de localisation et de définition de la mission des unités d’affaires au sein d’un réseau logistique. Elles se prennent à l’égard de la portion de logistique inversée du réseau, particulièrement à l’égard des centres de récupération et de traitement ainsi que des entrepôts de produits valorisés, tout en considérant le fonctionnement courant de la chaîne d’approvisionnement. Elles abordent également l’orientation stratégique des produits vers les alternatives de traitement suivant les possibilités de récupération de produits et la condition du réseau, soit en accord avec les volumes de demande et de récupération, les capacités des sites et les coûts d’opération du réseau. Le réseau est abordé sous un environnement stochastique à l’égard des volumes de demande, de récupération et de traitement, suivant l’état des produits récupérés. Des approches de modélisation sont proposées pour définir les paramètres clés du modèle de programmation mathématique devant servir à la conception d’un tel réseau. Une heuristique basée sur la méthode d’approximation de la moyenne d’échantillonnages (« Sample Average Approximation - SAA »), impliquant les techniques d’échantillonnage de Monte Carlo, est proposée pour résoudre le modèle stochastique. La méthodologie est appliquée au contexte d’attribution, de maintenance, de récupération, de traitement et de redistribution des fauteuils roulants dans la province de Québec, au Canada, régi et administré par la Régie de l’assurance maladie du Québec (RAMQ).This thesis proposes a generic methodology for designing logistics networks integrating reverse logistics into a current supply chain. Such networks involve the recovery of unused products from the end-users, and their processing and redistribution toward new users. According to their state, recovered products may be repaired, disassembled for the recovery of parts and disposed. Reusable products resulting from processing are indicated as valorised products. They represent an economical supply source, which meets a lower quality standard compared to new products. The methodology aims at supporting decisions on location and definition of mission of business units. They relate to the reverse logistics portion of a network, particularly as regards recovery and processing centres as well as warehouses for valorised products, while considering the current operating context of a supply chain. Decisions also tackle the strategic proportion of products to be directed toward processing alternatives according to the product recovery possibilities and network conditions, which relate to the recovery and demand volumes with respect to the capacity constraints and operating costs. The network is evaluated in a stochastic environment with regard to the demand, recovery and processing volumes, according to recovered product states. Modeling approaches are proposed to define key parameters for the related mathematical programming model. A heuristics based on the Sample Average Approximation (SAA) method, involving the Monte Carlo sampling methods, is proposed to solve the stochastic model. The methodology is validated with the wheelchair allocation, maintenance, recovery, processing and redistribution context in the Province of Quebec, Canada, governed and managed by the Quebec Health Insurance Board (Régie de l’assurance maladie du Québec - RAMQ)

    Système organisationnel et architecture d'un support d'information sur l'intégration des activités de logistique inversée au sein d'un centre de réadaptation

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    Dans ce mémoire, on traite de problèmes reliés à l'intégration et au pilotage des activités de logistique inversée au sein d'une organisation. Les activités de logistique inversée font référence à la récupération de produits inutilisés ou en fin de cycle de vie, à leur traitement et à la redistribution des matériels réutilisables. Pour illustrer les concepts abordés, un nouveau système organisationnel, qui représente le déroulement des processus opérationnels et l'exploitation des ressources de l'organisation (main-d'uvre, matériel, équipement, etc.), et une architecture de support d'information ont été proposés pour la situation vécue par un centre de réadaptation. Celui-ci, comme l'ensemble des centres de réadaptation de la province de Québec, se voit désormais confronté à la récupération et au traitement de fauteuils roulants inutilisés de sa clientèle en plus des activités courantes d'attribution et de maintenance.Les concepts développés peuvent non seulement s'étendre aux autres centres de réadaptation, mais également s'appliquer avantageusement à plusieurs applications, autant dans le secteur de production de bien que de service

    The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

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    Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

    Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

    A stochastic programming approach for designing supply loops

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    A stochastic programming model for designing logistics networks integrating reverse logistics into current supply chains is proposed in this paper. It aims at evaluating impacts of randomness related to recovery, processing and demand volumes on the design decisions. These decisions deal with the location of service and processing centres and warehouses, regarding processed products with reuse potential, the definition of mission of sites and, consequently, the product accessibility. Flows of recovered products may be directed toward one or a number of processing alternatives, according to the different states of the recovered products as well as to the network conditions, which relate to recovery and demand volumes with respect to capacity constraints and operating costs. Notably, recovered products may be repaired, disassembled for part refurbishing or disposed. Such products are indicated here as valorized products and represent an economical supply alternative, which meets lower quality standards in comparison with new products. Portions of needs fulfilled by valorized products are defined according to the requirements of end-users, as well as management policies and strategies. The model aims at improving valorized product accessibility, while reducing the total operating costs of such a network. A heuristics based on the sample average approximation, involving the Monte Carlo sampling methods, is proposed to solve the problem

    Design of reverse logistics networks for multiproducts, multistates, and multiprocessing alternatives

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    This chapter proposes a modeling methodology for designing reverse logistics networks. The model aims at determining the location and missions of sites for the recovery of unused products from ultimate consumers, valorization or clean disposal of recovered products, redistribution of reusable materials, and attribution of new or reusable (valorized) products. Valorization activities refer to repair, refurbishing, reassembling, product disassembly for reusable material recovery (cannibalization), and recycling. The proportion of recovered product volumes to orient to valorization and clean disposal activities is not known a priori but is determined according to demand and return volumes, site capacities, and the general anticipated state of recovered product volumes. This model may be used to evaluate the impact of reintegrating valorized products (finished products and spare parts) into current supply chains initially designed only for distribution and maintenance of new products. The chapter discusses key parameters such as the localization and estimation of potential returns and demands for new and reusable (valorized) products, as well as the probability that a returned product be in a specific state, which could lead to one or many processing alternatives (repair, disassembly, clean disposal, etc.). This mathematical model is inspired by the recent healthcare allocation and valorization of the wheelchair policy of the Province of Quebec (Canada), governed and managed by a governmental agency

    Integration of reverse logistics activities within a supply chain information system

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    This article deals with problems related to the integration of reverse logistics activities within an organization and to the coordination of this new system. Reverse logistics activities refer to the recovery and processing of unused products and to the redistribution of reusable materials. For better control and management of these activities, new approaches and information support system are proposed here. A new organizational system, which represents the course of the operational processes and the management of the organization’s resources (labor, material, etc.), and an information system architecture are proposed for a rehabilitation center
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