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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

Microsimulation of Public Transport Stops for the Optimization of Waiting Times for Users Using the Social Force Model

Mendoza, Francis, Tong, Mayling, Silvera, Manuel, Campos, Fernando 01 January 2021 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Cities in the world aim to ensure the mobility of people, through the implementation of efficient Integrated Transportation Systems (ITS). This aims to improve the transport of people, which guarantees that they can be mobilized safely and without delays in the terminals and bus stops of the public transport system. The present article proposes a design of public transport stops aimed at optimizing the waiting time of users when transferring from one bus to another. For the validity of the proposal, the social force model of the Vissim program was used, where the behavior of the users within the bus stops was reflected. The results showed that the waiting times in the calibrated and validated microsimulation model were optimized by approximately 20%, which generates an improvement in the efficiency of the public transport system. / Revisión por pares
22

Offshore-Containerterminals als Transshipment-Hub - dargestellt am Beispiel der Deutschen Bucht / Offshore-Containerterminals used as transshipment-hub - shown on the example of the German Bight

Reise, Sönke 23 July 2005 (has links) (PDF)
Deutlich ansteigende interkontinentale Handelsbeziehungen bilden die wesentliche Grundlage das Wachstum der Containerschifffahrt. Die Schnittstelle der Containerschifffahrt zu den landgebundenen Verkehrsträgern bilden Containerterminals. Deren Entwicklung muss im Zusammenhang mit der Containerschifffahrt gesehen werden. Die Entwicklung des Containerschifffahrtsmarktes wird sich auch in Zukunft weiter dynamisch fortsetzen. Prognosen zur Umschlagsentwicklung sind für die Containerterminals von besonderem Interesse, da die Containerterminals bestrebt sind, genügend Kapazitäten bereitzustellen. Im Umfeld eines Containerterminals sowie in ihnen selbst können diverse Kapazitätsengpässe entstehen. In vielen Fällen ist dringender Handlungsbedarf hinsichtlich der Beseitigung von potenziellen Engpässen gegeben. Eine Option stellt dabei der Neubau von Containerterminals dar. Der Hafenbau wird in dichtbesiedelten Räumen zunehmend schwieriger und teurer. Die aus heutiger Sicht zur Verfügung stehenden Flächen werden langfristig nicht ausreichen, um das Umschlagsaufkommen der Zukunft zu bewältigen. Deswegen kann die Errichtung von herkömmlichen Containerterminals langfristig nicht als ausschließliche Option zur Beseitigung von Umschlagsengpässen angesehen werden. Das Konzept eines Offshore-Containerterminals (OCT) stellt einen alternativen Ansatz dar, der zukünftige Engpässe vermeidet oder ihre Auswirkungen mindert. Ziel des Konzepts ist die Verlagerung von Transshipments von den herkömmlichen Containerterminals auf einen OCT. Dieses Konzept wird auf seine wirtschaftliche Tragfähigkeit untersucht. Letzlich stellt das Konzept des OCTs als Transshipment-Hub eine Möglichkeit dar, die unter heutigen Verhältnissen zwar unrentabel erscheint, unter zukünftigem Expansionsdruck und Kostensteigerungen bei der Erschließung neuer Terminalflächen jedoch als Konzept ökonomisch konkurrenzfähig sein kann und eventuell ohne Alternative ist.
23

Offshore-Containerterminals als Transshipment-Hub - dargestellt am Beispiel der Deutschen Bucht

Reise, Sönke 22 February 2005 (has links)
Deutlich ansteigende interkontinentale Handelsbeziehungen bilden die wesentliche Grundlage das Wachstum der Containerschifffahrt. Die Schnittstelle der Containerschifffahrt zu den landgebundenen Verkehrsträgern bilden Containerterminals. Deren Entwicklung muss im Zusammenhang mit der Containerschifffahrt gesehen werden. Die Entwicklung des Containerschifffahrtsmarktes wird sich auch in Zukunft weiter dynamisch fortsetzen. Prognosen zur Umschlagsentwicklung sind für die Containerterminals von besonderem Interesse, da die Containerterminals bestrebt sind, genügend Kapazitäten bereitzustellen. Im Umfeld eines Containerterminals sowie in ihnen selbst können diverse Kapazitätsengpässe entstehen. In vielen Fällen ist dringender Handlungsbedarf hinsichtlich der Beseitigung von potenziellen Engpässen gegeben. Eine Option stellt dabei der Neubau von Containerterminals dar. Der Hafenbau wird in dichtbesiedelten Räumen zunehmend schwieriger und teurer. Die aus heutiger Sicht zur Verfügung stehenden Flächen werden langfristig nicht ausreichen, um das Umschlagsaufkommen der Zukunft zu bewältigen. Deswegen kann die Errichtung von herkömmlichen Containerterminals langfristig nicht als ausschließliche Option zur Beseitigung von Umschlagsengpässen angesehen werden. Das Konzept eines Offshore-Containerterminals (OCT) stellt einen alternativen Ansatz dar, der zukünftige Engpässe vermeidet oder ihre Auswirkungen mindert. Ziel des Konzepts ist die Verlagerung von Transshipments von den herkömmlichen Containerterminals auf einen OCT. Dieses Konzept wird auf seine wirtschaftliche Tragfähigkeit untersucht. Letzlich stellt das Konzept des OCTs als Transshipment-Hub eine Möglichkeit dar, die unter heutigen Verhältnissen zwar unrentabel erscheint, unter zukünftigem Expansionsdruck und Kostensteigerungen bei der Erschließung neuer Terminalflächen jedoch als Konzept ökonomisch konkurrenzfähig sein kann und eventuell ohne Alternative ist.
24

Metodologia para mapeamento de zonas operacionais em sistemas de transmissão VSC-HVDC. / Methodology for mapping operational zones in VSC-HVDC transmission sytems.

Itiki, Rodney 31 January 2018 (has links)
Sistemas de transmissão de energia elétrica em corrente contínua e alta tensão baseados em tecnologia de conversores a fonte de tensão (VSC-HVDC), ao contrário de linhas de transmissão em corrente alternada, operam como elementos de controle de variáveis elétricas, podendo ser úteis na estabilidade do sistema de potência. Mas apesar desta vantagem, sistemas VSC-HVDC possuem limitações no desempenho estável, o que enseja o desenvolvimento de uma metodologia para mapeamento de suas zonas de operação estável e possíveis regiões de instabilidade. Inicialmente estudou-se os detalhes da tecnologia VSC-HVDC tais como o funcionamento da eletrônica de potência e estratégias de controle utilizadas. Em seguida, investigou-se os modelos de geradores síncronos para interconexão com o lado CA das estações conversoras do VSC-HVDC. E, finalmente, aplicou-se a tecnologia VSC-HVDC sobre um modelo de sistema de potência com uma estação conversora localizada em um porto offshore e uma outra no continente, próxima à rede de alta tensão em corrente alternada. Simulações e análise deste sistema foram executadas considerando várias condições operacionais. O gráfico de potência gerada e consumida, obtido pela aplicação da metodologia, apresenta grande potencial de uso prático como por exemplo sua implementação na interface homem-máquina da estação de operação do porto offshore, provendo informação em tempo real de alto nível ao operador do sistema elétrico do porto offshore e consequentemente aumentando sua consciência situacional quanto a proximidade dos limites de instabilidade. / High voltage direct current power transmission systems based on voltage source converters (VSC-HVDC), as opposed to alternating current ones, operates as elements of control of electrical variables, being useful for stability of power system. Besides this advantage, VSC-HVDC systems have limitations in stable performance, which instigates the development of a methodology for mapping its operational zones of stability and possible regions of instability. The author initially studied the details of the VSC-HVDC technology such as the power electronic principles and the control strategies used on this research. Subsequently, the author investigated synchronous generator models for interconnection on the AC side of the VSC-HVDC converter stations. Finally, the author applied the VSC-HVDC technology on a model of power system with two converter stations, one located on an offshore port and the other on the shore, next to an alternating current high voltage power grid. Simulations and analysis of this system were carried out considering various operational conditions. The graphic of generated and consumed power on offshore port, obtained by the application of the methodology for mapping operational zones, presents a great potential of being implemented in the man-machine interface of an operation workstation, thus providing high level online information for the operator of the offshore port electrical system and consequently improving its situational awareness of the proximity to instability limits.
25

Metodologia para mapeamento de zonas operacionais em sistemas de transmissão VSC-HVDC. / Methodology for mapping operational zones in VSC-HVDC transmission sytems.

Rodney Itiki 31 January 2018 (has links)
Sistemas de transmissão de energia elétrica em corrente contínua e alta tensão baseados em tecnologia de conversores a fonte de tensão (VSC-HVDC), ao contrário de linhas de transmissão em corrente alternada, operam como elementos de controle de variáveis elétricas, podendo ser úteis na estabilidade do sistema de potência. Mas apesar desta vantagem, sistemas VSC-HVDC possuem limitações no desempenho estável, o que enseja o desenvolvimento de uma metodologia para mapeamento de suas zonas de operação estável e possíveis regiões de instabilidade. Inicialmente estudou-se os detalhes da tecnologia VSC-HVDC tais como o funcionamento da eletrônica de potência e estratégias de controle utilizadas. Em seguida, investigou-se os modelos de geradores síncronos para interconexão com o lado CA das estações conversoras do VSC-HVDC. E, finalmente, aplicou-se a tecnologia VSC-HVDC sobre um modelo de sistema de potência com uma estação conversora localizada em um porto offshore e uma outra no continente, próxima à rede de alta tensão em corrente alternada. Simulações e análise deste sistema foram executadas considerando várias condições operacionais. O gráfico de potência gerada e consumida, obtido pela aplicação da metodologia, apresenta grande potencial de uso prático como por exemplo sua implementação na interface homem-máquina da estação de operação do porto offshore, provendo informação em tempo real de alto nível ao operador do sistema elétrico do porto offshore e consequentemente aumentando sua consciência situacional quanto a proximidade dos limites de instabilidade. / High voltage direct current power transmission systems based on voltage source converters (VSC-HVDC), as opposed to alternating current ones, operates as elements of control of electrical variables, being useful for stability of power system. Besides this advantage, VSC-HVDC systems have limitations in stable performance, which instigates the development of a methodology for mapping its operational zones of stability and possible regions of instability. The author initially studied the details of the VSC-HVDC technology such as the power electronic principles and the control strategies used on this research. Subsequently, the author investigated synchronous generator models for interconnection on the AC side of the VSC-HVDC converter stations. Finally, the author applied the VSC-HVDC technology on a model of power system with two converter stations, one located on an offshore port and the other on the shore, next to an alternating current high voltage power grid. Simulations and analysis of this system were carried out considering various operational conditions. The graphic of generated and consumed power on offshore port, obtained by the application of the methodology for mapping operational zones, presents a great potential of being implemented in the man-machine interface of an operation workstation, thus providing high level online information for the operator of the offshore port electrical system and consequently improving its situational awareness of the proximity to instability limits.
26

Méthodes de modélisation et d'optimisation par recherche à voisinages variables pour le problème de collecte et de livraison avec transbordement / Modeling method and optimization by the variable neighborhood search for the pickup and delivery problem with transshipment

Tchapnga Takoudjou, Rodrigue 12 June 2014 (has links)
La présente thèse se déroule dans le cadre du projet ANR PRODIGE et est axée sur la recherche de stratégies permettant l’optimisation du transport en général et du transport routier de marchandises en particulier. Le problème de transport support de cette étude est le problème de collecte et livraison avec transbordement. Ce problème généralise plusieurs problèmes de transports classiques. Le transbordement y est utilisé comme levier de flexibilité et d’optimisation. Pour analyser et résoudre ce problème, les analyses sont effectuées suivant trois axes : le premier axe concerne l’élaboration d’un modèle analytique plus précisément d’un modèle mathématique en variables mixtes. Ce modèle permet de fournir dessolutions optimales au décisionnaire du transport mais présente l’inconvénient de nécessiter un temps de résolution qui croit exponentiellement avec la taille du problème. Cette limitation est levée par le deuxième axe d’étude qui permet de résoudre le problème de transport étudié par une méthode d’optimisation approchée tout en garantissant des solutions satisfaisantes.La méthode utilisée est une métaheuristique inspirée de la recherche à voisinages variables (VNS). Dans le troisième axe, l’ensemble des résultats obtenus dans la thèse sont testés en situation de transports réels via le projet PRODIGE. / The thesis is conducted under the ANR project PRODIGE and it is focused on seeking strategies allowing the optimization of transport in general and road freight transport in particular. The transportation problem support for this study is the pickup and delivery problem with transshipment.This problem generalizes several classical transportation problems.Transshipment is used as optimization and flexibility leverage. To study and solve this problem, analyzes are performed along three axes :the first objective concerns the development of an analytical model, more accurately a mathematical model with mixed variables. This model allows providing optimal solution to the decision maker, but has the disadvantage of requiring a time resolution that grows exponentially with the size of the problem. This limitation is overcome by the second line of the study that solves the transportation problem studied by an approximate optimization method while ensuring satisfactory solutions. The method used is a mataheuristic broadly followed the variables neighborhoods research principles. In the third objective, the overall results obtained in the thesis are tested in real transport situation via the PRODIGE project.
27

Gigantisme naval et ports d'escale : un nouveau paradigme

de Champlain, Philippe 12 1900 (has links)
La croissance de la taille des porte-conteneurs et leur déploiement sur les grandes routes maritimes mondiales est une réalité. Actuellement, la croissance de la capacité des porte-conteneurs a atteint 21 413 EVP, et les carnets de commandes laissent présager une tendance vers des navires encore plus grands. Par exemple, le transporteur CMA CGM devrait recevoir neuf nouveaux porte-conteneurs de 23 000 EVP d'ici la fin de l’année 2020. L’objectif de ce mémoire est de caractériser le mouvement des méga porte-conteneurs sur plusieurs routes maritimes, avec différents transporteurs et régions du monde. Cet objectif comporte deux volets; le premier porte sur l’analyse de la variabilité du temps des escales de méga-navires dans les ports, et le deuxième fait l’étude de la planification des routes de méga-navires pour les transporteurs maritimes. Les données historiques du mouvement d'un grand échantillon de méga-navires ont été analysées en vue de répondre à une série de questions permettant de structurer la recherche. Cette dernière permettra entre autres d’identifier les ports recevant des escales de méga-navires, d’évaluer la variabilité des temps d’escale ainsi que de présenter l’architecture des routes maritimes de ce type de navires. Enfin, cette étude permet de différencier la productivité des ports d'escale, des régions du monde et des transporteurs sur plusieurs routes maritimes. / The growth in the size of container vessels and their deployment is a reality. Currently, the growth of container ships is at 21 413 TEUs, and the order books for ever larger vessels portend an even greater trend towards larger vessels. For instance, CMA CGM will be delivered nine new 23 000 TEU container ships by the end of 2020. The objective of this paper is to characterize the movement of ultra-large container vessels (ULCV) on several shipping routes, with different carriers and regions of the world. This objective is two-fold; the first part deals with the variability of the dwell time of ULCV in the ports, and the second deals with the planning of ULCV routes for each maritime carrier. Historical data of the movement of a large sample of ULCV was analysed with a view to address a series of key issues. Here are some of these issues: What are the mains ports of call? What is the variability of dwell time between the ports of call? What are the routing patterns of mega containers vessels? This study will allow us to differentiate productivity of different ports of call, regions and shipping carriers on many shipping lanes.
28

我國國際海運政策之研究─從保護到解制之變革 / A Study of Taiwan's International Shipping Policy: From Protection to Deregulation

楊繼明, Young, Aaron Unknown Date (has links)
戰後台灣的政治安定,立基於經濟發展,經濟發展取決於貿易傳動。在全球化的時代,經貿是台灣積極串聯世界、爭取生存茁壯的關鍵樞紐;對四面環海的台灣而言,能源及原物料之進口與轉化後財貨之對外貿易,全賴於海運實踐,台灣以一個海島型經濟型態「不斷向世界市場擴張」的過程中,國際海運是國家經濟與世界市場的實質聯結。國際海運因而成為台灣迎向全球與經貿發展的生命線,政軍安定的守護神。 本文主要的目的,在探討戰後(1950~2005)我國國際海運政策的治理模式與治理政策。台灣四面環海,具有發展國際海運的地理優勢,比較世界各國的發展,台灣地區的國際海運經營與發展,在世界上一直佔有相當重要的地位。然而,近年來,由於中國大陸的崛起,台灣則基於自身的考量,執行「戒急用忍」政策,遲遲不開放兩岸通航與協商航商西進,使得台灣的經濟優勢逐漸流失,國輪航商之經營環境也隨之惡化,本研究藉由歷史與結構的研究途徑,從戰後我國國際海運發展的歷史脈絡與結構變遷,就其治理模式與治理策略進行深入的探討。 除了經由文獻探討中,檢視我國國際海運政策的變革之外,進一步與我國國際海運的公經理人、學者與業者等共三十位專業人士,進行實證的訪問調查,獲得第一手的資料,然後與文獻分析所得相互驗證,進而歸納成結論,並就我國國際海運政策的治理模式與治理策略,提出建言。 / Abstract: Comparing with the development of other countries, water-surrounded Taiwan has to build up its international shipping industry to facilitate international trade and therefore stabilize its polity through economic development. Due to the geographic privilege, Taiwan also has its strength of developing international shipping for linking the national economy and the world market. The objective of this study is to explore the governance mode and strategies of Taiwan’s international shipping policy after the World War II. This study investigated the relationships among international politics, macroeconomic and international trade, government policy, and industry environment for the international shipping policy. In addition to literature review, this study interviewed public managers, scholars and industrial professionals to empirically collect the experienced data by “in-depth interview.” Through the integrated means, this study concludes that Taiwan’s international shipping policy has played an important role for developing the industry in each stage of Taiwan’s development on economy and international trade, whilst the government in Taiwan should seek more practical governance modes and strategies to cope with the challenges to come.
29

PICKUP AND DELIVERY PROBLEM WITH TRANSFERS AND ELECTRIC VEHICLES

Cansu Agrali Oner (12394297) 26 April 2022 (has links)
<p>Online retail sales and grocery/food orders have been breaking records every year. As a result, third-party delivery companies have found an opportunity to get their share from the growing transportation network. Electric vehicles (EVs) are becoming a preferable choice for such large delivery systems due to their environmental benefits. However, EVs have limited-service ranges; therefore, intra-route facilities are needed for EVs to stay operational. These facilities offer charging stations for EVs and storage areas for requests, e.g., food and packages. In this dissertation, we propose a novel <em>Pickup and Delivery Problem</em> (PDP) with EVs and transfers. There are requests to be picked up and delivered. EVs leave their origin depot, serve requests, and return to their destination depot. Unlike the generic PDP, intra-route facilities allow EVs to exchange requests. Thus, a request can be transported by more than one vehicle. In this dissertation, three new problems are introduced, and the following research questions are investigated: 1) "How valuable is to include intra-route facilities and allow transfers in a pickup and delivery network with EVs?", 2) "What is the cost of locating intra-route facilities randomly rather than finding the best locations while creating the routes for EVs?", and 3) "How much can drones improve the delivery speed in a pickup and delivery network with EVs and transfers?". A <em>Mixed-integer Linear Programming</em> (MILP) model and a <em>Simulated Annealing</em> (SA) algorithm are developed and compared with each other to answer the first question. For the second question, a MILP model is formulated; however, due to unreasonable computational runtimes, a SA algorithm and an <em>Adaptive Large Neighborhood Search</em> (ALNS) algorithm are proposed. Finally, a MILP model is developed for the hybrid-fleet problem. The overall results highlight that intra-route facilities shorten the total traveled distance in the PDP network by allowing exchanges and recharging.</p>

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