55 research outputs found
Sur la prise en compte de la qualité environnementale des produits dans la conception des chaines logistiques vertes
Environmental concerns are increasingly impacting customers’ behavior as well as companies’ strategies. In this context, optimizing the supply chain with environmental considerations is becoming a critical issue. In this thesis we focus on this issue. An originality of our work is to show that supply chain design decisions (facility location, choice of production processes, transportation modes, etc.) impact the environmental quality of a product and therefore affect the level of its demand and / or its selling price. Demand and price are no longer considered as exogenous variables as often done in supply chain optimization existing works, but rather as endogenous variables. In this work we propose a set of supply chain optimization models that take into account the product environmental quality and customers’ preferences towards product environmental quality. Based on a case study from the textile sector, we show the relevance of considering the products’ environmental quality in supply chain optimization models.Les enjeux environnementaux impactent de plus en plus le comportement des clients ainsi que les stratégies des entreprises. Dans ce contexte, l’optimisation de la chaine logistique en tenant compte des questions environnementales devient un enjeu critique. Dans cette thèse nous nous intéressons à cette problématique. Une originalité de ce travail est de montrer que les décisions prises lors de la conception d’une chaine (localisation des sites, choix des processus de production, de transport,…) ont une influence sur la qualité environnementale d’un produit perçue par les clients, et influent donc sur le niveau de la demande et/ou prix de ces produits. La demande et le prix ne sont plus des variables exogènes comme pratiquement toujours considéré dans les travaux existants, mais bien des variables endogènes. Dans cette thèse nous proposons alors des modèles d’optimisation des activités logistiques en tenant compte de la qualité environnementale des produits élaborés et des préférences clients. Nous montrons grâce à des expérimentations sur un cas d’étude du secteur de textile, la pertinence de la considération de la qualité environnementale des produits dans les modèles d’optimisation des activités logistiques
Émissions de carbone dans un modèle de production-stocks multi-echelon avec prise en compte des contraintes de délai
Colloque avec actes et comité de lecture. internationale.International audienceNous développons un modèle mathématique d'optimisation qui intègre les émissions de carbone dans un modèle gestion production-stock multi-échelon sous des contraintes de délai. Le modèle proposé capte l’impact de certaines décisions logistiques sur les émissions carbone. Nous nous intéressons principalement aux décisions suivantes : production des produits finis et intermédiaire, approvisionnement chez des fournisseurs internes et externes, positionnement des stocks des différents produits (fini et intermédiaires) aux différents niveaux de la chaîne logistique. Nous considérons deux types de réglementation environnementale: (1) taxe sur les émissions et (2) seuil infranchissable d'émissions carbone. Nous utilisons le modèle pour réaliser un ensemble d’expérimentations et fournir une série d’implications managériales
Government strategies to secure the supply of medical products in pandemic times
We investigate how to secure reliable access to personal protective equipment (PPE) in pandemics, which are characterized by random occurrences and durations, at the lowest expected cost. The policymaker\u27s strategy is based on a mix of (1) holding ready-to-use strategic stockpile that is acquired at regular price but incurs a holding cost, (2) building partnership with PPE manufacturers to relocate offshore production locally, which guarantees some local supply but requires offering subsidies, and (3) buying PPE from the spot market, which is characterized by long supply lead times and high prices. We model the problem as a Stackelberg game between a policymaker (leader) and a manufacturer (follower). The policymaker decides the PPE stockpile, the subsidy offered to the local manufacturer, and the quantity to buy from the spot market. The manufacturer determines whether to move production onshore. We determine the optimal strategy for each player and study the effect of spot market conditions and pandemic characteristics. Analytical results show that attracting local manufacturers is less costly for the government when the variability of pandemic duration increases. While it is sub-optimal to rely only on the strategic stockpile, holding some stockpile may be necessary even when the PPE can be obtained from the spot market as soon as the pandemic starts. Results reveal policymaker\u27s preference for subsidizing onshore production in the following cases: products with low spot prices (counter-intuitively), spot market with long supply lead time, less frequent pandemics, and shorter pandemics
Study of lipid profile and parieto-temporal lipid peroxidation in AlCl3 mediated neurotoxicity. modulatory effect of fenugreek seeds
<p>Abstract</p> <p>Background</p> <p>Peroxidation of lipid (LPO) membrane and cholesterol metabolism have been involved in the physiopathology of many diseases of aging brain. Therefore, this prospective animal study was carried firstly to find out the correlation between LPO in posterior brain and plasmatic cholesterol along with lipoprotein levels after chronic intoxication by aluminium chloride (AlCl<sub>3</sub>). Chronic aluminum-induced neurotoxicity has been in fact related to enhanced brain lipid peroxidation together with hypercholesterolemia and hypertriglyceridemia, despite its controversial etiological role in neurodegenerative diseases. Secondly an evaluation of the effectiveness of fenugreek seeds in alleviating the engendered toxicity through these biochemical parameters was made.</p> <p>Results</p> <p>Oral administration of AlCl<sub>3 </sub>to rats during 5 months (500 mg/kg bw i.g for one month then 1600 ppm via the drinking water) enhanced the levels of LPO in posterior brain, liver and plasma together with lactate dehydrogenase (LDH) activities, total cholesterol (TC), triglycerides (TG) and LDL-C (Low Density Lipoproteins) levels. All these parameters were decreased following fenugreek seeds supplementation either as fenugreek seed powder (FSP) or fenugreek seed extract (FSE). A notable significant correlation was observed between LPO<sub>brain </sub>and LDL-C on one hand and LDH<sub>liver </sub>on the other hand. This latter was found to correlate positively with TC, TG and LDL-C. Furthermore, high significant correlations were observed between LDH<sub>brain </sub>and TC, TG, LDL-C, LPO<sub>brain </sub>as well as LDH<sub>liver</sub>.</p> <p>Conclusion</p> <p>Aluminium-induced LPO in brain could arise from alteration of lipid metabolism particularly altered lipoprotein metabolism rather than a direct effect of cholesterol oxidation. Fenugreek seeds could play an anti-peroxidative role in brain which may be attributed in part to its modulatory effect on plasmatic lipid metabolism.</p
On the design of green supply chains
Les enjeux environnementaux impactent de plus en plus le comportement des clients ainsi que les stratégies des entreprises. Dans ce contexte, l’optimisation de la chaine logistique en tenant compte des questions environnementales devient un enjeu critique. Dans cette thèse nous nous intéressons à cette problématique. Une originalité de ce travail est de montrer que les décisions prises lors de la conception d’une chaine (localisation des sites, choix des processus de production, de transport,…) ont une influence sur la qualité environnementale d’un produit perçue par les clients, et influent donc sur le niveau de la demande et/ou prix de ces produits. La demande et le prix ne sont plus des variables exogènes comme pratiquement toujours considéré dans les travaux existants, mais bien des variables endogènes. Dans cette thèse nous proposons alors des modèles d’optimisation des activités logistiques en tenant compte de la qualité environnementale des produits élaborés et des préférences clients. Nous montrons grâce à des expérimentations sur un cas d’étude du secteur de textile, la pertinence de la considération de la qualité environnementale des produits dans les modèles d’optimisation des activités logistiques.Environmental concerns are increasingly impacting customers’ behavior as well as companies’ strategies. In this context, optimizing the supply chain with environmental considerations is becoming a critical issue. In this thesis we focus on this issue. An originality of our work is to show that supply chain design decisions (facility location, choice of production processes, transportation modes, etc.) impact the environmental quality of a product and therefore affect the level of its demand and / or its selling price. Demand and price are no longer considered as exogenous variables as often done in supply chain optimization existing works, but rather as endogenous variables. In this work we propose a set of supply chain optimization models that take into account the product environmental quality and customers’ preferences towards product environmental quality. Based on a case study from the textile sector, we show the relevance of considering the products’ environmental quality in supply chain optimization models
Carbon emissions in a multi-echelon production-inventory model with lead time constraints
International audienc
Effects of Customers' Environmental Awareness and Environmental Regulations on the Emission Intensity and Price of a Product
International audienc
Time- and price-based product differentiation in hybrid distribution with stockout-based substitution
International audienceA delivery mix that includes delivery from stock and drop-shipping is of interest to many internet retailers. We consider a retailer serving a time- and price-sensitive market with two substitutable products that differ in the guaranteed delivery time and price, an express product (delivered from the stock) and a regular product (drop-shipped). In case of stockout, customers may switch from the express product to the regular product. We study how to differentiate the products in terms of delivery times and prices and how to determine the stock level to maximize the retailer's expected profit while satisfying service constraints. We solve different variants of the problem and derive insights into the optimal retailer's strategy. In addition, we study the impact of stockout-based substitution. This paper is the first to investigate time- and price-based differentiation along with inventory decisions for a retailer who relies on a hybrid distribution to satisfy a time- and price-sensitive demand subject to stockout-based substitution. When prices and stock are fixed, in addition to minimum and maximum time differentiations, a medium differentiation strategy may be optimal but depends on the stock level. When only prices are fixed, there exists a price differentiation limit below which a minimum time differentiation is optimal, and above which only the express product should be offered. For the general model, numerical experiments show that a higher stockout-based substitution leads to greater time differentiation (which is consistent with the results of previous models) and more stock. However, this would not impact the price differentiation
Planning the supply of emergency medical products to cope with pandemics
The COVID-19 pandemic exposed inadequate planning in the supply of emergency medical products (EMP) worldwide. In what followed, an exponential growth in EMP demand during the first months of the pandemic proved extremely challenging for manufacturers to adapt to. This put healthcare workers, our first line of defense, in jeopardy and stretched healthcare systems beyond their capacities. Many governments realized the deficiency of their emergency stockpile policies, and as global demand outstripped supply, they struggled to meet their population\u27s basic EMP needs using offshore suppliers. In this work, we present a game theoretical approach for the planning of EMP supplies using a game that models the interaction between governments and private manufacturers to secure such critical supplies in the case of pandemics, while reducing the overall cost to taxpayers, and taking into consideration manufacturers profit objectives. On one hand, a policymaker can decide the strategic stockpile size for EMPs and use subsidies to encourage manufacturers to onshore some or all of their EMP manufacturing capacity to improve their domestic crisis management capabilities in case of a pandemic. On the other hand, private manufactures can evaluate offshoring cost savings compared to subsidies offered by the government on the condition of onshoring production of subsidized products and offering such items to the public at contracted pricing in pandemics. We detail the two models, present a solution to balance the competing objectives, and discuss insights from the model\u27s analysis
The effect of greenness- and price-based competition on a product's environmental performance
International audienc
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