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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

Omlastningsteminal - En studie av miljöeffekter vid införande av omlastningsterminal och ruttplaneringssystem i Kalmar kommun

Jina, Tina, Quist, Johanna, Svensson, Elise January 2010 (has links)
Title: Transshipment Terminal – A study of environmental effects from the introduction of a transshipment terminal and a route planning system in the municipality of Kalmar Examiner: Andersson, Petra Key words: Transshipment terminal, route planning, environmental impact Purpose: The study aims to examine how a transshipment terminal and a route planning system may have implications for the municipality of Kalmar from environmental concerns. Methodology: The thesis is a case study on the municipality of Kalmar. A positivistic -and an objectivistic approach have been used. The strategic approach that was used was quantitative. Theoretical perspectives: The thesis has mainly been based on theories of transshipment terminal, route planning and environmental impact, but also other relevant theories have been used. Emperical foundation: Empirical data has gathered through interviews with the municipality of Kalmar and its suppliers and from data that was obtained from them. The information has then been analyzed using the theoretical framework. Conclusions: By imposing a transshipment terminal and route planning for the municipality of Kalmar, the number of transports, transport distance and carbon dioxide emissions can be reduced. transshipment terminal can be analyzed, and how suppliers can change their routes when a transshipment terminal is inmplemented. Also where the transshipment terminal should be placed can be another subject to study. Suggestions for further research: The authors suggest that a deeper study of the total costs of
2

Transportation Service Provider Collaboration Problem: Potential Benefits and Solution Approaches

Roesch, Robert Steven 28 February 2017 (has links)
Truck-based freight transportation continues to play a vital role in the delivery of goods in the United States. Despite its size and importance, the truck transportation industry continues to struggle with fulfilling transportation requests in an efficient and sustainable manner. One potential solution to alleviate many of the current truck industry problems is for transportation service providers (TSPs) to collaborate by sharing volume, resources, and facilities. This research introduces the Transportation Service Provider Collaboration Problem (TSP-CP) to demonstrate the benefits of using optimal freight routing and consolidation decisions for collaborating TSPs. A mathematical model for the TSP-CP is introduced to describe the problem in detail. Additionally, two separate adaptive large neighborhood search (ALNS) heuristics are developed to provide solutions to industry representative problem instances. Finally, the benefits and insights achieved by enabling collaboration between TSPs using the TSP-CP are identified using industry representative data sets. The representative data sets were derived from actual freight data provided by a freight pooling company that manages collaboration among TSPs. Carriers were chosen from the industry data to evaluate collaborative partnerships and to gain insights on the effects of partnership characteristics on overall benefit as well as the benefits obtained by individual carriers. The computational results suggested collaboration among TSPs offers the potential for substantial reductions in the total distance required to deliver all loads, in the number miles that were traveled completely empty, and the number of containers required for delivery compared to individual performance. Additionally, collaboration increased delivery resource capacity utilization as measured by the percentage of weighted full miles. Detailed analysis of the results from the TSP-CP revealed new insights into the collaboration between full truckload and less-than truckload carriers that have not been quantified or highlighted in previous research. These insights included the effect that an individual carrier's type and size had on the amount of benefit received to each carrier. Finally, the results highlighted the importance of building collaborative partnerships that consider a carrier's geographic location. / Ph. D. / Truck-based freight transportation continues to play a vital role in the delivery of goods in the United States by carrying nearly 70% of all freight tonnage. Despite its size and importance, the truck industry continues to struggle with transporting freight in an efficient, timely, and sustainable manner. One potential solution to alleviate many of the current truck industry problems is for transportation service providers (TSP) to collaborate by sharing resources, facilities, and freight volume. This research introduces the Transportation Service Provider Collaboration Problem (TSP-CP) to demonstrate the benefits of using optimal freight routing and consolidation decisions for collaborating TSPs. The benefits and insights achieved by enabling collaboration between TSPs using the TSPCP are identified using industry representative data sets. The representative data sets were derived from actual freight data provided by a freight pooling company that manages collaboration among TSPs. The computational results suggested collaboration among TSPs offers the potential for substantial reductions in the total distance required to deliver all freight, in the number of miles that were traveled by containers completely empty, and in the number of containers required for delivery compared to individual performance. Additionally, collaboration increased delivery resource capacity utilization. Detailed analysis of the results from the TSP-CP also revealed new insights into TSP collaboration. These insights included the effect that an individual carrier’s type and size had on the amount of benefit received to each carrier. Finally, the results highlighted the importance of building collaborative partnerships that consider a TSP’s geographic location.
3

Holdout transshipment policy in two-location inventory systems

Zhang, Jiaqi January 2009 (has links)
In two-location inventory systems, unidirectional transshipment policies are considered when an item is not routinely stocked at a location in the system. Unlike the past research in this area which has concentrated on the simple transshipment policies of complete pooling or no pooling, the research presented in this thesis endeavors to develop an understanding of a more general class of transshipment policy. The research considers two major approaches: a decomposition approach, in which the two-location system is decomposed into a system with independent locations, and Markov decision process approach. For the decomposition approach, the transshipment policy is restricted to the class of holdout transshipment policy. The first attempt to develop a decomposition approach assumes that transshipment between the locations occurs at a constant rate in order to decompose the system into two independent locations with constant demand rates. The second attempt modifies the assumption of constant rate of transshipment to take account of local inventory levels to decompose the system into two independent locations with non-constant demand rates. In the final attempt, the assumption of constant rate of transshipment is further modified to model more closely the location providing transshipments. Again the system is decomposed into two independent locations with non-constant demand rates. For each attempt, standard techniques are applied to derive explicit expressions for the average cost rate, and an iterative solution method is developed to find an optimal holdout transshipment policy. Computational results show that these approaches can provide some insights into the performance of the original system. A semi-Markov decision model of the system is developed under the assumption of exponential lead time rather than fixed lead time. This model is later extended to the case of phase-type distribution for lead time. The semi-Markov decision process allows more general transshipment policies, but is computationally more demanding. Implicit expressions for the average cost rate are derived from the optimality equation for dynamic programming models. Computational results illustrate insights into the management of the two-location system that can be gained from this approach.
4

ESTUDO DE CASO SOBRE TRANSFERÊNCIAS LOGÍSTICAS, COM A UTILIZAÇÃO DE VEÍCULOS SEMIRREBOQUE DE DUPLO PISO

Oliveira, Rafael Jesus de 06 October 2015 (has links)
Submitted by admin tede (tede@pucgoias.edu.br) on 2016-10-07T12:25:37Z No. of bitstreams: 1 Rafael Jesus de Oliveira.pdf: 1124242 bytes, checksum: fa371be37cc03a3dc85c778e22d63002 (MD5) / Made available in DSpace on 2016-10-07T12:25:37Z (GMT). No. of bitstreams: 1 Rafael Jesus de Oliveira.pdf: 1124242 bytes, checksum: fa371be37cc03a3dc85c778e22d63002 (MD5) Previous issue date: 2015-10-06 / The purpose of this dissertation is to analyze the use of semi-trailer vehicles with single and double floors process transfers and transshipments, common in logistics operations when they have more than one distribution center or industrial complex. These different manifestations contribute very little to the final value of the product, and is characterized by a high cost to organizations, resources aimed at reducing costs or increasing efficiency should be the subject of academic studies. To this end the research approaches in a comparative way the two models, with quantitative data obtained in a company that uses the two models presented trough case study in order to explore the pattern of transshipment and drives. / A proposta desta dissertação é a de analisar a utilização de veículos semirreboque com piso simples e duplo em processos de transferências e transbordos, comuns em operações logísticas quando possuem mais de um centro de distribuição ou complexo industrial. Como estas movimentações diversas pouco ou nada agregam em valor ao produto final, e tem como característica um elevado custo paras as organizações, recursos que visam diminuir despesas ou aumentar eficiência devem ser alvo de estudos acadêmicos. Com este intuito a pesquisa aborda de forma comparativa os dois modelos, com dados quantitativos conseguidos em uma empresa que utiliza os dois modelos apresentado através do estudo de caso, com o objetivo de explorar o padrão dos transbordos e movimentações.
5

Pickup and delivery problems with side constraints

Qu, Yuan, Ph. D. 22 February 2013 (has links)
Pickup and delivery problems (PDPs) have been studied extensively in past decades. A wide variety of research exits on both exact algorithms and heuristics for generic variations of the problem as well as real-life applications, which continue to spark new challenges and open up new opportunities for researchers. In this dissertation, we study two variations of pickup and delivery problem that arise in industry and develop new computational methods that are shown to be effective with respect to existing algorithms and scheduling procedures found in practice. The first problem is the pickup and delivery problem with transshipment (PDPT). The work presented here was inspired by a daily route planning problem at a regional air carrier. In structuring the analysis, we describe a unique way to model the transshipment option on a directed graph. With the graph as the foundation, we implemented a branch and price algorithm. Preliminary results showed that it has difficulty in solving large instances. As an alternative, we developed a greedy randomized adaptive search procedure (GRASP) with several novel features. In the construction phase, shipment requests are inserted into routes until all demand is satisfied or no feasible insertion exists. In the improvement phase, an adaptive large neighborhood search algorithm is used to reconstruct portions of the feasible routes. Specialized removal and insertion heuristics were designed for this purpose. We also developed a procedure for generating problem instances in the absence of any in the literature. Testing was done on existing PDP data sets and generated PDPT data set. For the former, the performance and solution quality of the GRASP were comparable to the best known heuristics. For the latter, GRASP found the near optimal solution in most test cases. In the second part of the dissertation, we focus on a new version of the heterogeneous PDP in which the capacity of each vehicle can be modified by reconfiguring its interior to satisfy different types of customer demands. The work was motivated by a daily route planning problem arising at a senior activity center. A fleet of configurable vans is available each day to transport participants to and from the center as well as to secondary facilities for rehabilitative and medical treatment. To find solutions, we developed a two-phase heuristic that makes use of ideas from greedy randomized adaptive search procedures with multiple starts. In phase I, a set of good feasible solutions is constructed using a series of randomized procedures. A representative subset of those solutions is selected as candidates for improvement by solving a max diversity problem. In phase II, an adaptive large neighborhood search (ALNS) heuristic is used to find local optima by reconstructing portions of the feasible routes. Also, a specialized route feasibility check with vehicle type reassignment is introduced to take full advantage of the heterogeneous nature of vehicles. The effectiveness of the proposed methodology is demonstrated by comparing the solutions it provided for the equivalent of several weeks with those that were used in practice and derived manually. The analysis indicates that anywhere from 30% to 40% savings can be achieved with the multi-start ALNS heuristic. An exact method is introduced based on branch and price and cut for settings with more restricted time windows. In the procedure, the master problem at each node in the search tree is solved by column generation to find a lower bound. To improve the bound, subset-row inequalities are applied to the variables of the master problem. Columns are generated by solving the pricing subproblems with a labeling algorithm enhanced by new dominance conditions. Local search on the columns is used to quickly find promising alternatives. Implementation details and ways to improve the performance of the overall procedure are discussed. Testing was done on a set of real instances as well as a set of randomly generated instances with up to 50 customer requests. The results show that optimal solutions are obtained in majority of cases. / text
6

[en] MULTI-VEHICLES MULTI-PRODUCTS INVENTORY ROUTING PROBLEM WITH TRANSSHIPMENT: A CASE STUDY / [pt] ROTEIRIZAÇÃO DE MULTI-VEÍCULOS E MULTI-PRODUTOS COM ESTOQUE E TRANSBORDO: UM ESTUDO DE CASO

NATHALIA JUCA MONTEIRO 18 September 2017 (has links)
[pt] O transporte e os estoques correspondem a maior parte dos custos logísticos de uma empresa. Com o avanço da tecnologia, passou-se a analisar em conjunto esses dois componentes e não mais separados, como era feito anteriormente. O Problema de Roteirização de Veículos com Estoque (Inventory Routing Problem – IRP), nasceu dessa análise conjunta e procura encontrar a melhor rota para os veículos, atendendo a um determinado nível de estoque. Este trabalho apresenta um modelo de IRP com múltiplos veículos e produtos, onde existe a possibilidade de transbordo entre os centros de distribuição existentes. O modelo desenvolvido foi elaborado em um estudo de caso real em uma empresa do setor varejista. Após sua elaboração, o modelo foi testado com uma instância menor e comparado a situação atual da empresa, a fim de testar sua eficiência. Em seguida, foi rodado com os dados completos da empresa, e foram analisados os resultados. Na resolução, foi utilizado o software Xpress, o qual utiliza programação inteira como método de resolução. / [en] Transport and inventories account for most of a company s logistics costs. With the advancement of technology, we began to analyze these two components together and no longer separate, as was done previously. The Inventory Routing Problem (IRP) was born from this joint analysis and seeks to find the best route for the vehicles, meeting a certain level of inventory. This work presents an IRP model with multiple vehicles and products, where there is the possibility of transshipment between existing distribution centers. The developed model was elaborated in a real case study in a company of the retail sector. After its elaboration, the model was tested with a smaller instance and compared to the current situation of the company in order to test its efficiency. It was then run with the complete company data, and the results were analyzed. In the resolution, Xpress software was used, which uses integer programming as the resolution method.
7

Analyzing Supply Chain Networks for Blood Products

Xu, Yuan January 2019 (has links)
The blood supply chain, starting from the donor until the blood is used to meet transfusion demands of patients, is a multi-echelon and complex system. The perishable and lifesaving characteristics of blood products, such as red blood cells and platelets, as well as uncertainties in both supply and demand make it difficult to maintain a balance between shortage and wastage due to expiry. An effective blood supply chain should be able to meet the demand while at the same time reducing wastage and total operational cost. In order to be cost effective, the related organizations have to decide how much blood should be collected from donors, how much blood products should be produced at the blood center, and how much blood products should be distributed to hospitals or transshipped between hospitals. The objective of this dissertation is to provide these tactical and operational decisions to guide those who work in healthcare supply chain management and explore new opportunities on performance improvement for an integrated blood supply chain by optimization with aim of minimizing total cost, consideration of transshipment between hospitals, and application of a coordinated multi-product model. This dissertation presents three multi-stage stochastic models for an integrated blood supply chain to minimize total cost incurred in the collection, production, inventory, and distribution echelons under centralized control. The scope of this study focuses on modeling a supply chain of blood products in one regional blood center, several hospitals and blood collection facilities. First, we develop an integrated model for the platelet supply chain that accounts for demand uncertainty and blood age information, then we develop this model further by investigating the impact of transshipment between hospitals on cost savings, and then we propose a multi-product model that accounts for red blood cells and platelets at the same time and compare it with an uncoordinated model where the red blood cell and platelet supply chains are considered separately.
8

Pevnostní analýza a optimalizace nosné konstrukce překládacího vozu. / Strength analysis and optimization of the structure of the car transshipment.

Suchý, Martin January 2012 (has links)
This master’s thesis has been prepared with Romill company cooperation. It deals with strength analysis and optimization of the structure of the car transshipment. It consist strength analysis of the original construction, the proposed changes and strength analysis of the modified construction.
9

Inventory Systems with Transshipments and Quantity Discounts

Noble, Gregory Daniel January 2012 (has links)
No description available.
10

Modeling transnational surface freight flow and border crossing improvement

Matisziw, Timothy C. 14 July 2005 (has links)
No description available.

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