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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.
21

Logística de baixo carbono: avaliação da eficiência do modal cabotagem no transporte de longa distância. / Low carbon logistics: evaluating the efficiency of modal cabotage in long distance transportation.

Rodrigues, Edmilson Roberto 20 December 2018 (has links)
Este estudo estima e compara as emissões de CO2 entre os dois modos de transporte intermodais mais utilizados no Brasil, para cargas com origem e destino ao município de Manaus, Estado do Amazonas. O primeiro é denominado cabotagem porta-a-porta, tem o contêiner como unidade de transporte e é caracterizado pela utilização da navegação em rios e/ou oceano como modalidade principal, complementado por caminhões para os trechos rodoviários na origem e destino. O segundo modo de transporte consiste na combinação do modo fluvial com rodoviário, conhecido no mercado brasileiro como rodo-fluvial. Nesse modal, a unidade de transporte é usualmente a carreta-baú, que percorre uma parte do trajeto sobre uma barcaça (trecho fluvial) e outra parte conectada a um cavalo-mecânico (trecho rodoviário). Através da aplicação dos métodos de cálculo baseados na energia ou atividade (energy-based or activity-based approach) foi possível realizar uma comparação das emissões de forma bastante compreensiva. Na literatura existem diversos estudos que destacam a eficiência do modal aquaviário em relação ao modal rodoviário. No entanto, esses estudos analisam as emissões sem considerar todas as etapas envolvidas, como coleta e entrega, e movimentação portuária. Dessa forma, esses estudos podem estar deixando de computar quantidades importantes de emissões quando fazem essas comparações. Nesse estudo, a comparação contempla todas as etapas e permite que ao analisarmos os resultados, possamos entender exatamente em qual etapa do processo as emissões são mais significativas. Os resultados apurados apontam uma clara vantagem ambiental do modal cabotagem porta-a-porta, emitindo até 40% menos CO2 que o modal rodo-fluvial no trecho entre Manaus e São Paulo. De igual forma, mostra-se também mais eficiente mesmo em trechos de menor distância, como entre Manaus e Recife, onde as emissões na cabotagem porta-a-porta são 54% inferiores ao modal rodo-fluvial. Quando comparado com rotas puramente rodoviárias, como entre Porto Alegre e Recife, a cabotagem porta-a-porta emite 63% menos CO2 que o modal alternativo. / This study estimates and compares CO2 emissions between the two modalities of intermodal transport most used in Brazil for cargo with origin and destination to the municipality of Manaus, State of Amazonas. The first is called door-to-door cabotage, has the container as a transport unit and is characterized by the use of river and/or ocean navigation as the main modality, complemented by trucks for the road sections at the origin and destination. The second mode is the combination of the fluvial and road modal, known in the Brazilian market as a fluvial highway. In this modality, the transport unit is usually the trailer, which travels part of the route on a barge (river sections) and another part connected to a tractor (road sections). Through the application of the energy-based or activity-based approach, it was possible to compare the emissions in a very comprehensive way. In the literature there are several studies that highlight the efficiency of the waterway modal in relation to the road modal. However, these studies analyze emissions without considering all the steps involved, such as pick-up and delivery and port handling. Thus, these studies may be failing to compute significant amounts of emissions when making such comparisons. In this study, the comparison contemplates all the steps and allows that when analyzing the results, we can understand exactly at which stage of the process the emissions are more significant. The results obtained indicate a clear environmental advantage of the modal cabotage door-to-door, emitting up to 40% less CO2 than the combined fluvial and road modal in the stretch between Manaus and São Paulo. Similarly, it is also shown to be more efficient even in smaller distances, such as between Manaus and Recife, where the emissions in the door-to-door cabotage are 54% lower than the alternative (fluvial-road) modal. When compared to purely road routes, such as between Porto Alegre and Recife, the door-to-door cabotage emits 63% less CO2 than the alternative modal.
22

Distribuição modal rodo-ferroviária em uma rede de exportação de açúcar a granel para o Porto de Santos / Railroad distribution at a bulk sugar exportation network to the port of Santos

Vitor Borges da Silva 26 April 2005 (has links)
Atualmente, o Brasil é o maior produtor de açúcar do mundo, com uma produção anual de 16,7 milhões de toneladas, onde a metade deste montante destina-se ao mercado externo. Nesse contexto, este trabalho tem o objetivo principal de investigar as principais alternativas de transporte existentes para o açúcar a granel de exportação, e propor estratégias que orientem os agentes envolvidos neste mercado a racionalizar seus custos de distribuição. São criados três grupos de cenários que representam as principais alternativas de transporte neste setor: o rodoviário porta-a-porta; o rodo-ferroviário com restrição de capacidade de embarque de açúcar; e um cenário de longo prazo de transporte rodo-ferroviário sem restrição de capacidade de embarque de açúcar. Em cada um desses grupos existe a opção de se transportar nos trechos rodoviários, tanto no porta-a-porta como nas pontas de acesso à ferrovia, com frota própria ou terceirizada. As tecnologias para frotas próprias investigadas nesse trabalho são as CVCs 2S3 e 3S3, geralmente utilizadas para o transporte do açúcar a granel, e as 3S2B2 e 3S3B3, as quais tem participações incipientes nesse mercado de transportes. A modelagem do problema leva em consideração os custos econômicos para a operação das frotas próprias e os valores de fretes cobrados para o setor tanto no modo rodoviário, como no ferroviário. Esses modelos agregados são simulados com auxílio de um sistema de informação geográfica e de planilhas eletrônicas. Ao final, conclui-se que no transporte rodoviário porta-a-porta, embora existam vantagens econômicas na operação das novas CVCs, nenhuma alternativa de frota própria mostra-se mais viável que a contratação de frota terceirizada no mercado. As análises no modo rodo-ferroviário mostram que este é mais atraente do que o rodoviário porta-a-porta para o mercado de exportação de açúcar, mesmo quando a operação tem restrições de capacidade. Numa operação hipotética sem restrições de capacidade, os ganhos econômicos gerados são da ordem 5,3% sobre a alternativa rodo-ferroviária com restrição da ferrovia para embarque de açúcar. Sugere-se a realização de uma investigação dos custos de investimento na infra-estrutura e material rodante necessários para eliminar as restrições de capacidade para este mercado. / Brazil is today the largest sugar producer of the world, with an annual production of 16,7 milion tons, where half of this amount is directed to be export market. In this context, the study has the main objective to investigate the transport alternatives for bulk sugar export and to propose strategies to the market agents involved in rationalizing the distribution costs. Three groups of scenarios are created to represent the main transportation alternatives in this sector: the door-to-door road transport; the constrained capacity road-railroad intermodal transport; and a long-term unconstrained capacity road-railroad intermodal scenario. For each of these scenarios the option of the road transport, either in the door-to-door operation or in the accesses to the railroad, with proprietary or third party fleets is investigated. The technologies for proprietary fleets considered in this investigation are the 2S3 and 3S3 combinations, generally used at present for the bulk sugar transportation, as well as the 3S2B2 and 3S3B3 LCVs, which have an incipient participation in this transportation market. The modeling considers the economic costs for the proprietary fleet operations and current freight values charged for road and rail in the bulk sugar transport sector in the region selected for the case study for the third party operation. The aggregate cost models are simulated with the support of a geographic information system and electronic spreadsheets. It is concluded that in the door-to-door road transport, even considering the economic advantages of the new LCVs technologies, none of the proprietary fleet alternatives are more cost effective than contracting third party fleets in the market. The railroad alternatives show that this alternative is more attractive than the door-to-door road transport, even considering the constraints in operating capacity. An hypothetical operation with unconstrained capacity is presented, showing that the economic gains of this alternative are in the order of 5,3% better than the best constrained capacity alternative. A suggestion to conduct an investigation on the investment costs necessary to eliminate infrastructure and rolling stock capacity constrains on the railroad network is presented.
23

Διαχείριση συνδυασμένων μεταφορικών συναλλαγών μέσω της ολοκλήρωσης υβριδικών συστημάτων συστάσεων και τεχνικών εξόρυξης γνώσης

Λαζανάς, Αλέξης 27 April 2009 (has links)
Η παρούσα διδακτορική διατριβή αναφέρεται σε μια ειδική κατηγορία Πληροφοριακών Συστημάτων, αυτή των Συστημάτων Ηλεκτρονικής Αγοράς. Πιο συγκεκριμένα, αποτελεί μια προσπάθεια ολοκλήρωσης υβριδικών Τεχνικών Συστάσεων και Τεχνικών Εξόρυξης Γνώσης, με παράλληλη ενσωμάτωσή τους σε ένα πλαίσιο διαχείρισης συνδυασμένων μεταφορών και αξιοποίηση σύγχρονων Τεχνολογιών Διαδικτύου. Λαμβάνοντας υπόψη τη διαπιστωμένη ανάγκη για την ανάπτυξη καινοτόμων συστημάτων διαχείρισης συνδυασμένων μεταφορών, η διατριβή παρουσιάζει αναλυτικά τις φάσεις ανάπτυξης ενός τέτοιου συστήματος. Το προτεινόμενο σύστημα δέχεται αιτήσεις μεταφορικών συναλλαγών και έχει τη δυνατότητα κατασκευής άμεσων ή τμηματικών λύσεων με την χρήση κατάλληλων αλγορίθμων Επιχειρησιακής Έρευνας. Στο συγκεκριμένο σύστημα ενσωματώνονται υβριδικές τεχνικές συστάσεων με σκοπό την παροχή υψηλού επιπέδου πληροφόρησης στους εμπλεκόμενους χρήστες. Επιπλέον η διατριβή προτείνει ένα πρωτότυπο υβριδικό μοντέλο συστάσεων με τη συνδυασμένη χρήση μεθόδων συστάσεων και τεχνικών εξόρυξης γνώσης. Η ανάπτυξη του παραπάνω μοντέλου αποσκοπεί στην αντιμετώπιση των μειονεκτημάτων που προκύπτουν από τη χρήση προηγούμενων τεχνικών και τη βελτίωση των παρεχόμενων υπηρεσιών. Στο προτεινόμενο σύστημα συμμετέχουν και αλληλεπιδρούν, μέσω αυστηρά ορισμένων πρωτοκόλλων, ένα σύνολο ευφυών πρακτόρων, αναλαμβάνοντας την διεκπεραίωση μιας σειράς απαραίτητων εργασιών για την πραγματοποίηση των μεταφορικών συναλλαγών. Το σύστημα βασίζεται στον Παγκόσμιο Ιστό και υλοποιήθηκε με τη χρήση σύγχρονων Τεχνολογιών Διαδικτύου. / This PhD thesis refers to a specific area of Information Systems called E-Market Systems. More specifically, it represents an attempt to integrate hybrid Recommendation techniques as well as data mining methods, encapsulating them at the same time, into an intermodal transportation transactions management framework, through the exploitation of innovative internet technologies. Taking into consideration the urgent need for the development of innovative intermodal transportations management systems, this thesis presents analytically all the phases of the development of such a system. The proposed system accepts requests for transportation transactions and is capable of constructing direct or modular transportation solutions exploiting suitable Operation Research Algorithms. The system encapsulates hybrid recommendation techniques – aiming at providing a high level of information to the involved users. Moreover, this thesis proposes an innovative hybrid recommendation model which combines recommendation methods and data mining techniques. The development of the above model, aims at facing up the problems that rise by the use of the recommendation methods mentioned before and at the enhancement of the provided services. In the proposed system, an agents’ community participate and interact with each others, through well defined communication protocols, with the responsibility of performing all the necessary tasks for the establishment of a transportation transaction. The proposed system is Web-based and implemented through the use of modern Web technologies.
24

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.
25

Optimization of operative planning in rail-road terminals

Bruns, Florian 16 September 2014 (has links)
Rail-road terminals are the chain links in intermodal rail-road transportation where standardized load units (containers, swap bodies and trailers) are transfered from trucks to trains and vice versa. We consider three subproblems of the operational planning process at rail-road terminals that terminal operators are facing in their daily operations. These are the optimization problems storage planning, load planning and crane planning. The aim of storage planning is to determine load unit storage positions for a set of load units in a partially filled storage area. Here, different restrictions like non-overlapping of stored load units have to be respected. The objective of storage planning is to minimize the total transportation costs and the number of load units that are not stored at the ground level. For the load planning we assume a scenario of overbooked trains. So, the aim of load planning is to assign a subset of the load units that are booked on a train to feasible positions on the wagons such that the utilization of the train is maximized and the costs for the handling in the terminal are minimized. For the feasible positioning of load units length and weight restrictions for the wagons and the train have to be respected. For the load planning of trains we consider a deterministic version and a robust approach motivated by uncertainty in the input data. The last considered optimization problem is the crane planning. The crane planning determines the transfer of the load units by crane between the different transportation modes. For each crane a working plan is computed which contains a subset of the load units that have to be handled together with individual start times for the transfer operations. For the load units which have to be transfered in the terminal, storage and load planning compute destination positions (inside the terminal). These destination positions are part of the input for the crane planning. The main objective of crane planning is to minimize the total length of the empty crane moves that have to be performed between successive transports of load units by the cranes. We provide MIP-models for all three subproblems of the operational planning process at rail-road terminals. For the storage and crane planning we also propose fast heuristics. Furthermore, we present and compare computational results based on real world data for all subproblems. The main contributions of this thesis concern load and storage planning. For the deterministic load planning we provide the first model that represents all practical constraints including physical weight restrictions. For the load planning we furthermore present robustness approaches for different practical uncertainties. For the storage planning we provide complexity results for different variants. For the practical setting we developed a heuristic which is able to compute solutions of high quality in a small amount of runtime.

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