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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.
11

Application of Micro Cloud for Cooperative Vehicles

gona, rishitha 01 September 2020 (has links)
The emerging concept of vehicle cloudification is a promising solution to deal with ever-growing computational and communication demands of connected vehicles. A key idea is to have connected vehicles in the vicinity form a cluster which is called vehicular micro cloud. Vehicles in this micro cloud collaborate with other cluster members over vehicle-to-vehicle (V2V) networks for collective data processing, shared data storage, collaborative sensing and communication services. A typical use case of vehicular micro cloud is creation of a regional distributed data storage service, where member vehicles of the cloud collaboratively keep data contents in their on-board data storage devices. This allows vehicles in and around the vehicular micro cloud to request the contents from the micro cloud member(s) over vehicle-to-vehicle networks, or even update the data on the spot. In this thesis, we will discuss the need for vehicular micro clouds, followed by the architecture, formation of the micro clouds, and feasibility of micro clouds. Furthermore, we will cover aspects of efficient data transmission between vehicles, how to increase the scalability and to make it time efficient and cost efficient on practical road conditions for moving vehicles by encouraging coordination between neighboring micro cloud to help transfer data .
12

Modified Trajectory Shaping Guidance for Autonomous Path Following Control of Platooning Ground Vehicles

Erekson, Ishmaal T. 01 May 2016 (has links)
This thesis proposes a modification of trajectory shaping guidance to provide more accurate path convergence in curved paths. The object of this thesis is to apply this simple guidance law to platooning control to ensure all vehicles in the platoon converge to a desired constant radius path at a desired vehicle separation distance. To show the viability of this new guidance law, it is shown mathematically to be exponentially stable. It is also confirmed through simulations and on ground robots.
13

THE ROLE OF PLATOONING IN FREIGHT TRANSIT EFFICIENCY

Alshiddi, Reem 01 May 2023 (has links) (PDF)
With the progress and expansion of civilization, companies are interested in distributing their products and goods in distributed areas on a daily basis. These daily tasks are considered to ensure that the products reach the largest possible number of people to keep pace with accommodating the expansion and population. However, these daily duties demand a lot of effort and are financially burdened on both drivers and companies as well. Besides that, daily transportation might cause traffic congestion as well as being negative on the environment with harmful emissions coming from heavy-duty trucks. With overcrowding, companies may face delays in the arrival of their products to their customers, which is a point that may reflect negatively on the company's reputation in the business. One of the proposed solutions for companies to deal with these problems is to create a platoon of trucks during their transportation between the pickup stations and the drop-off stations. The literature review demonstrates that there are written benefits for the truck platoons, however, there is a lack of showing these benefits in the reality. The platoon simulation was built in this thesis to present the results numerically so that they could be contrasted with scenarios where the platoon was not used for freight transportation. This thesis focused on the benefits of a platoon from three aspects: the aspect of saving time, reducing cost by reducing fuel usage, and finally increasing safety in public driving on highways. The results of using the simulations showed that the time was using to deliver the goods by using truck platoons was shorter than the time by using individual trucks. Additionally, traffic congestion was less when the trucks were driven on single-lane on highways, which causes reduced the number of accidents especially, those that occurred with small cars. They compiled accident data between 2007 and 2017, coming to the conclusion that 98,790 crashes involving large trucks were among the 243,017 total crashes. In the same survey, the authors found that 9.4% of truck accidents occurred when changing lanes with small cars on highways. This thesis demonstrated numerically that there was less fuel usage while the trucks were driven in a platoon compared with the fuel usage of the trucks that were driven individually. In a word, transportation companies will gain benefits from using truck platoons to deliver their goods to their customers.
14

Development of automatic vehicle headway control law and a simulation tool

Yao, Mingdong 24 January 2009 (has links)
Vehicle following and its effects on traffic flow has been an active area of research. Human Driving involves reaction, delays, and human errors that has adverse effects on traffic flow . We can eliminate human errors by introducing a computer control system. The purpose of this research was to develop and evaluate a control law and a simulation tool for the study of automatic vehicle headway control. This research considers longitudinal control of a platoon of vehicles on automated highways. A new way of designing control law for vehicle following is presented by introducing safe boundary concept - the trail vehicle should never exceed the maximum safe velocity and at the same time keeps the passengers comfort when accelerating or decelerating except under emergency circumstances. After finding the safe boundary, we design the automatic control law and then using our simulation tool to simulate its performance, adjust parameters until we reach a satisfactory result. System dynamics concept and basic individual vehicle motion laws are used through the research. System dynamics provides a common foundation that can be applied wherever we want to understand and influence how things change through time. We look at the platoon system as a whole and study all the objects, such as vehicle dynamics, road condition, motor dynamics, in this system interact with one another. A third-order nonlinear, Car-following, PID control law is designed using System Dynamics concept. System dynamics' simulation language DYNAMO and Spreadsheet are have been used for our development of a simulation tooL A Satisfactory result is found after the extensive simulation which indicates that the platoon assumptions are achievable using the advanced technologies, like automatic vehicle control, radar, and sensors. / Master of Science
15

Modeling Traffic Dispersion

Farzaneh, Mohamadreza 05 December 2005 (has links)
The dissertation studies traffic dispersion modeling in four parts. In the first part, the dissertation focuses on the Robertson platoon dispersion model which is the most widely used platoon dispersion model. The dissertation demonstrates the importance of the Yu and Van Aerde calibration procedure for the commonly accepted Robertson platoon dispersion model, which is implemented in the TRANSYT software. It demonstrates that the formulation results in an estimated downstream cyclic profile with a margin of error that increases as the size of the time step increases. In an attempt to address this shortcoming, the thesis proposes the use of three enhanced geometric distribution formulations that explicitly account for the time-step size within the modeling process. The proposed models are validated against field and simulated data. The second part focuses on implementation of the Robertson model inside the popular TRANSYT software. The dissertation first shows the importance of calibrating the recurrence platoon dispersion model. It is then demonstrated that the value of the travel time factor β is critical in estimating appropriate signal-timing plans. Alternatively, the dissertation demonstrates that the value of the platoon dispersion factor α does not significantly affect the estimated downstream cyclic flow profile; therefore, a unique value of α provides the necessary precision. Unfortunately, the TRANSYT software only allows the user to calibrate the platoon dispersion factor but does not allow the user to calibrate the travel time factor. In an attempt to address this shortcoming, the document proposes a formulation using the basic properties of the recurrence relationship to enable the user to control the travel time factor indirectly by altering the link average travel time. In the third part of the dissertation, a more general study of platoon dispersion models is presented. The main objective of this part is to evaluate the effect of the underlying travel time distribution on the accuracy and efficiency of platoon dispersion models, through qualitative and quantitative analyses. Since the data used in this study are generated by the INTEGRATION microsimulator, the document first describes the ability of INTEGRATION in generating realistic traffic dispersion effects. The dissertation then uses the microsimulator generated data to evaluate the prediction precision and performance of seven different platoon dispersion models, as well as the effect of different traffic control characteristics on the important efficiency measures used in traffic engineering. The results demonstrate that in terms of prediction accuracy the resulting flow profiles from all the models are very close, and only the geometric distribution of travel times gives higher fit error than others. It also indicates that for all the models the prediction accuracy declines as the travel distance increases, with the flow profiles approaching normality. In terms of efficiency, the travel time distribution has minimum effect on the offset selection and resulting delay. The study also demonstrates that the efficiency is affected more by the distance of travel than the travel time distribution. Finally, in the fourth part of the dissertation, platoon dispersion is studied from a microscopic standpoint. From this perspective traffic dispersion is modeled as differences in desired speed selection, or speed variability. The dissertation first investigates the corresponding steady-state behavior of the car-following models used in popular commercially available traffic microsimulation software and classifies them based on their steady-state characteristics in the uncongested regime. It is illustrated that with one exception, INTEGRATION which uses the Van Aerde car-following model, all the software assume that the desired speed in the uncongested regime is insensitive to traffic conditions. The document then addresses the effect of speed variability on the steady-state characteristics of the car-following models. It is shown that speed variability has significant influence on the speed-at-capacity and alters the behavior of the model in the uncongested regime. A method is proposed to effectively consider the influence of speed variability in the calibration process in order to control the steady-state behavior of the model. Finally, the effectiveness and validity of the proposed method is demonstrated through an example application. / Ph. D.
16

Mekaniserad spaning i dag och i framtiden / Mechanized reconnaissance today and future

Swande Eliasson, David January 2009 (has links)
<p>Den mekaniserade bataljonens främsta sensor att samla in underlag till underrättelsesektionen är spaningsplutonen. Spaningsplutonen på mekbataljon har bytt organisation över åren och gått från att vara ett terrängbils eller bandvagnsburet förband till sin nuvarande form med stridsfordon 90. Men har förbandet använts på rätt sätt sedan det tillfördes stridsfordon? Hur bör framtidens chefer nyttja plutonen för att maximera effekten?</p><p>Arbetet baseras på de reglementen som finns idag samt intervjuer med personal tillhörande spaningsplutonerna och bataljonsstaber. Utöver det kommer en jämförelse med US Army Armored Cavalry göras.</p> / <p>The mechanized battalion foremost instrument of gathering information to its intellegence cell is the reconnaissance platoon. The reconnaissance platoon on the mechanized battalion has evolved over the years from being a unit using crosscountry vehicles to its modern shape with Combat vehicle 90. But have the unit been used the right way since then? And how should tomorrows commanders use the recon platoon for maximum output?</p><p>This work will be based on the manuals that are valid today and interviews with staff officers and officers that belong to the recon platoons. The results will be compared with US Army Armored Cavalry.</p>
17

Mekaniserad spaning i dag och i framtiden / Mechanized reconnaissance today and future

Swande Eliasson, David January 2009 (has links)
Den mekaniserade bataljonens främsta sensor att samla in underlag till underrättelsesektionen är spaningsplutonen. Spaningsplutonen på mekbataljon har bytt organisation över åren och gått från att vara ett terrängbils eller bandvagnsburet förband till sin nuvarande form med stridsfordon 90. Men har förbandet använts på rätt sätt sedan det tillfördes stridsfordon? Hur bör framtidens chefer nyttja plutonen för att maximera effekten? Arbetet baseras på de reglementen som finns idag samt intervjuer med personal tillhörande spaningsplutonerna och bataljonsstaber. Utöver det kommer en jämförelse med US Army Armored Cavalry göras. / The mechanized battalion foremost instrument of gathering information to its intellegence cell is the reconnaissance platoon. The reconnaissance platoon on the mechanized battalion has evolved over the years from being a unit using crosscountry vehicles to its modern shape with Combat vehicle 90. But have the unit been used the right way since then? And how should tomorrows commanders use the recon platoon for maximum output? This work will be based on the manuals that are valid today and interviews with staff officers and officers that belong to the recon platoons. The results will be compared with US Army Armored Cavalry.
18

Proof of location as a security mechanism for vehicular Ad Hoc networks / Prova de localização como um mecanismo de segurança para redes veiculares

Boeira, Felipe Caye Batalha January 2018 (has links)
O desenvolvimento de redes veiculares possibilita o surgimento de sistemas inteligentes de transporte que podem aumentar a segurança nas vias, aperfeiçoar o controle de tráfego e fornecer entretenimento aos passageiros. O avanço e padronização de tecnologias de comunicação inter-veicular permitem que veículos compartilhem informações de forma colaborativa de maneira a viabilizar o estabelecimento de sistemas de transporte inteligentes cooperativos (C-ITS, Cooperative Intelligent Transportation Systems). Na comunicação veicular, cada nó compartilha periodicamente uma mensagem que contém informações sobre seu estado como posição, velocidade e aceleração. Estas mensagens são denominadas Cooperative Awareness Messages (CAMs) e podem ser utilizadas por veículos vizinhos para a operação de aplicações, sendo a formação de comboios um exemplo. Em um comboio veicular, um grupo de veículos viaja com distância reduzida entre cada membro através da operação de um controlador que utiliza informações compartilhadas por CAMs. O posicionamento compartilhado através de CAMs por cada veículo é crucial para a operação dos controladores de nós vizinhos, dado que este será utilizado para a condução do veículo. Embora os controles criptográficos padronizados para troca de mensagens em VANETs ofereçam contramedidas contra ataques como roubo de identidade e adulteração de pacotes, um atacante interno que possua credenciais válidas do sistema ainda pode mentir sobre as informações que são transmitidas para outros veículos. Em modelos atuais de redes veiculares, cada veículo é responsável por obter sua localização, normalmente através de GPS (Global Positioning System). A dependência de aplicações VANET na posição correta dos nós introduz a necessidade de mecanismos de garantia de localização. Nesta dissertação são identificados os riscos associados com a falsificação de posição em comboios veiculares. Através de simulações utilizando o ambiente de simulação Veins, mostramos que colisões em alta velocidade podem ser causadas por nós que atuam em conluio na falsificação de mensagens para um comboio. Dado que posicionamento legítimo é essencial para o funcionamento adequado das aplicações VANET, investigamos mecanismos de prova de localização propostos na literatura. Então, projetamos um mecanismo de prova de localização adaptado para VANETs usando equipamentos de estrada (RSUs, roadside units), com a capacidade de usar diferentes freqüências de prova de acordo com os requisitos de precisão de detecção e sobrecarga. Através de simulações usando os ataques estudados neste trabalho, mostramos que o mecanismo pode detectar ataques de falsificação de mensagens e Sybil. / In vehicular communication, nodes periodically share Cooperative Awareness Messages (CAMs) in order to convey information such as identity, velocity, acceleration and position. The positioning of nodes in a vehicular network is a key factor that directly affects how applications operate, being the formation of platoons a major case. In vehicular platooning, a group of vehicles travels closely together and leverages information shared through CAMs to operate lateral and longitudinal control algorithms. While the standardised cryptographic mechanisms counteract threats such as identity hijacking and packet tampering, an internal member who holds valid credentials may still be able to lie about the data it transmits in CAMs. In current Vehicular ad hoc Network (VANET) models, each vehicle is responsible for determining and informing its own position, generally using a Global Navigation Satellite System (GNSS) such as the Global Positioning System (GPS). This allows malicious actors to lie about their position and therefore cause unwanted effects in vehicular applications. The dependence of VANET applications on correct node localization introduces the need for position assurance mechanisms. In this dissertation, we first identify the risks associated with falsifying the position in vehicular platooning. Through simulations using the Veins framework, we show that collisions at high speed on a platoon may be caused by nodes that collude in falsification attacks. Given that truthful positioning is essential to proper behavior of VANET applications, we investigate proof-of-location schemes proposed in the literature. Then, a proof-of-location mechanism tailored for VANETs is designed using roadside units, with the capability of using different proof frequencies according to detection accuracy and overhead requirements. Through simulations using the studied attacks in this work, we show that the mechanism can counteract Sybil and message falsification attacks.
19

Bataljonsspaning : Ett verktyg i manöverkriget

Birath, Johan January 2009 (has links)
<p>Den här uppsatsen har initierats av en upplevd känsla att spaningsförbanden i den svenska armén på senare tid har eftersatts vad gäller antal och hur de nyttjas. Från att ha funnits i stor mängd vid flertalet förband finn nu endast vissa bataljonsspaningsförband kvar.</p><p>Hur dessa nyttjas kopplat till manöverbataljonernas strävan att tillämpa manövertänkande är också svårt att finna svar på i den litteratur som är aktuell i den svenska försvarsmakten.</p><p>Mitt syfte med uppsatsen är att skapa en vetenskaplig text som redogör för hur bataljonsspaningen vid den luftburna bataljonen skulle kunna utnyttjas för att stödja bataljonen i dess strävan att lyckas med manöverkrigföring.</p><p>Med min uppsats gör jag en ansats för att skapa en vetenskaplig text som svarar på frågan:</p><p><em>Hur bör bataljonsspaningsplutonen nyttjas för att stödja bataljonen i dess genomförande av manöverkrigföring?</em></p><p>För att svara på frågan använder jag mig i uppsatsen av en kvalitativ textanalys som jag i vissa fall kompletterar med intervjuer av inom området kunniga individer.</p><p>Det resultat jag kommit fram till är tätt kopplat till hur bataljonen kan använda sig av bataljonsspaningsplutonen för att stödja det dynamiska beslutsfattandet i syfte att maximera möjligheten att tillskansa sig ett ledningsöverläge gentemot motståndaren. Till exempel vikten av att använda bataljonsspaningsplutonen på djupet mot bataljonens andrahands mål och beredduppgifter i syfte att möjliggöra ett högt stridstempo.</p> / <p>This essay discusses how the Swedish air assault battalion could use its recon platoon to maximise their efforts to achieve manoeuvre warfare. The purpose with this essay is to clarify how to use the recon platoon in an effective way and to bring up some thoughts about the need for a manual on how to use recon platoons in light infantry battalions.</p><p>I have used literature that discusses the use of similar units to the air assault recon platoon and also literature that discusses how to lead a battalion in my efforts to clarify how the platoon should be used to support the battalions’ effort to achieve manoeuvre warfare. With help of the literature I have made a discussion and finally I came to some conclusions about how to use the battalions’ recon platoon in order to support the battalions´ effort to achieve manoeuvre warfare. For example one conclusion is the importance to use the recon platoon towards the battalions´ secondary objectives in order to gain a high tempo in operations.</p>
20

Åskkäpp, bössa och dunderpåk : Automatkarbinen i den svenska försvarsmakten / Thundercane, gun and thunderstick : The assault rifle in the Swedish Armed Forces

Lundin, Sven January 2010 (has links)
<p>Under 1990-talet märktes en tydlig förändring bland automatkarbinerna. De blev mer och mer anpassningsbara och fler tillbehör blev tillgängliga för soldaterna. Samtidigt blev automatkarbiner mer kompakta för att bli mer lämpliga för operationer i urbaniserad terräng och fordonstjänst. Med invasionen av Afghanistan och den därefter följande upprorsbekämpningen upplever många försvarsmakter problem, eftersom striderna sker på antingen väldigt korta eller väldigt långa avstånd. Den ena situationen kräver ett kompakt vapen för SIB medan den andra situationen kräver ett vapen med lång pipa för att kunna uppnå verkan mot en fiende som ofta anfaller från avstånd på 500 meter eller mer. Försvarsmakten hade just startat försök med en uppdaterad version av AK5 när de förband sig att bidra med en reguljär styrka till ISAF. Författaren är av åsikten att Försvarsmakten saknar ett vapensystem på grupp och plutonsnivå för att uppnå verkan på avstånd större än 400 meter som ofta är fallet. Denna uppsats syftar därför till att undersöka hur nästa svenska automatkarbin kan komma att se ut utifrån erfarenheter dragna ifrån Operation Enduring Freedom.</p> / <p>During the 1990ies there is notable change in the assault rifle. They start to get more and more adaptable with a lot more accessories being available to the user. At the same time the assault rifle moves from rifle to carbine as many models become shorter to better suit operations in urban terrainas well as riding in vehicles. With the invasion and the following counter-insurgency operation in Afghanistan a lot of armies are experiencing problems since combat takes places at either very short or long ranges. One calls for acompact carbine suited for close quarters battle and one for a long barrelled rifle which enables soldiers to engage the enemy who often attacks from ranges exceeding the 500 meter mark. The Swedish Armed Forces had just started testing a new updated version of their AK5 assault rifle called AK5C when they committed to contributing a regular force to ISAF. The Author is of the opinion that Swedish forces lack a weapon system on squad and platoon level to engage an enemy atgreater distance than 400m which is often the case. This paper seeks to take a look at what the next Swedish assault rifle could look like taking in mind the experiences from Operation Enduring Freedom.</p>

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