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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

GAP i efterfrågan : En undersökning om efterfrågan på miljövänliga transporter

Rehnström, Simon, Almlöf, Linnea January 2013 (has links)
Purpose: Corporations today see a greater responsibility towards society regarding the environmental impact of their actions, using available transportation options that are more eco-friendly can reduce this impact significantly. Martinsen and Björklund (2012) identifies a set of gaps between supply and demand of green logistics services. This paper aims to address what it is that affects the demand for these alternative solutions and what could be done to increase the usage of them, thereby decreasing this gap. Design/methodology/approach: A quantitative study with six Logistics Service Providers (LSP) and 24 companies that purchase transportation services, all operating in Sweden. Data is collected through semi-structured telephone interviews with people responsible for the purchasing of transports as well as key account managers within the service providing companies. Findings: Just as the LSP’s interviewed in this paper thought, the main focus of the transport buying companies are the costs. Therefore paying extra only to benefit the environment and not the economy of the company is not something a lot of companies are prepared to do at this time. However there are solutions such as intermodality which are highly demanded, these are often both cost effective and more environmentally friendly, the problem as many companies see it, is that the rail network needs to expand to be able to cover bigger areas and increase the capacity. Research limitations/implications: The research paper focuses on companies operating on the Swedish market, for that reason findings cannot be generalized to other countries and sectors. Practical implications: Findings can be used by LSP’s and political decision making parties to get a better understanding of the demand for this type of services and what is perceived as important by the customers. Originality/value: There is a lack of earlier studies that mainly focus on the demand of more environmentally friendly transport services. Therefore a study of this kind is important to create an understanding and thereby improve the overall situation on the market in terms of environmental sustainability.
2

Constrained Time-Dependent Adaptive Eco-Routing Navigation System / Systèmes eco-routing adaptatifs de navigation dépendant du temps avec des contraintes

Kubička, Matěj 16 November 2017 (has links)
L'éco-routage est une méthode de navigation du véhicule qui sélectionne les trajets vers une destination minimisant la consommation de carburant, la consommation d'énergie ou les émissions de polluants. C'est l'une des techniques qui tentent de réduire les coûts d'exploitation et l'empreinte environnementale du véhicule. Ce travail passe en revue les méthodes actuelles d'éco-routage et propose une nouvelle méthode pour pallier leurs insuffisances. La plupart des méthodes actuelles attribuent à chaque route du réseau routier un coût constant qui représente la consommation du véhicule ou la quantité de polluants émis. Un algorithme de routage optimal est ensuite utilisé pour trouver le chemin qui minimise la somme de ces coûts. Différentes extensions sont considérées dans la littérature. L'éco-routage contraint permet d'imposer des limites sur le temps de trajet, la consommation d'énergie et les émissions de polluants. L'éco-routage dépendant du temps permet le routage sur un graphique avec des coûts qui sont fonction du temps. L'éco-routage adaptatif permet de mettre à jour la solution d'éco-routage au cas où elle deviendrait invalide en raison d'un développement inattendu sur la route. Il existe des méthodes d'éco-routage optimales publiées qui résolvent l'éco-routage dépendant du temps ou l'éco-routage contraint ou l'éco-routage adaptatif. Chacun vient avec des frais généraux de calcul considérablement plus élevés par rapport à l'éco-routage standard et, à la connaissance de l'auteur, aucune méthode publiée ne prend en charge la combinaison des trois: éco-routage adaptatif dépendant du temps contraint. On soutient dans ce travail que les coûts d'acheminement sont incertains en raison de leur dépendance au trafic immédiat autour du véhicule, du comportement du conducteur et d'autres perturbations. Il est en outre soutenu que puisque ces coûts sont incertains, il y a peu d'avantages à utiliser un routage optimal car l'optimalité de la solution ne tient que tant que les coûts de routage sont corrects. Au lieu de cela, une méthode d'approximation est proposée dans ce travail. La charge de calcul est plus faible car la solution n'est pas requise pour être optimale. Cela permet l'éco-routage adaptatif dépendant du temps contraint. / Eco-routing is a vehicle navigation method that selects those paths to a destination that minimize fuel consumption, energy consumption or pollutant emissions. It is one of the techniques that attempt to lower vehicle's operational cost and environmental footprint. This work reviews the current eco-routing methods and proposes a new method designed to overcome their shortcomings. Most current methods assign every road in the road network some constant cost that represents either vehicle's consumption there or the amount of emitted pollutants. An optimal routing algorithm is then used to find the path that minimizes the sum of these costs. Various extensions are considered in the literature. Constrained eco-routing allows imposing limits on travel time, energy consumption, and pollutant emissions. Time-dependent eco-routing allows routing on a graph with costs that are functions of time. Adaptive eco-routing allows updating the eco-routing solution in case it becomes invalid due to some unexpected development on the road. There exist published optimal eco-routing methods that solve either the time-dependent eco-routing, or constrained eco-routing, or adaptive eco-routing. Each comes with considerably higher computational overhead with respect to the standard eco-routing and, to author's best knowledge, no published method supports the combination of all three: constrained time-dependent adaptive eco-routing. It is argued in this work that the routing costs are uncertain because of their dependence on immediate traffic around the vehicle, on driver's behavior, and other perturbations. It is further argued that since these costs are uncertain, there is little benefit in using optimal routing because the optimality of the solution holds only as long as the routing costs are correct. Instead, an approximation method is proposed in this work. The computational overhead is lower since the solution is not required to be optimal. This enables the constrained time-dependent adaptive eco-routing.
3

Intermodal Transportation within Green Supply Chain Management and Green Logistics : An Analysis of the Relationship between the Topics in the Literature and in Practice

Kiy, Kevin, Scanvic, Florian January 2018 (has links)
No description available.

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