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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

Identification and evaluation of solutions for long-haul electric road freight.

Lundström, Amanda, Lindén, Gustav January 2023 (has links)
Road freight transportation is important for the development of the global economy and, at the same time, one of the most destructive businesses when it comes to the environment and human health. As societies evolve, the need for freight transportation increases and the transport demand cannot in a sustainable way be fulfilled with the use of diesel trucks as it is done today. For the sake of our environment, the electrification transition needs to ramp up. However, when it comes to covering long distances with an electric truck, problems arise due to the lack of sufficient driving strategies, technology, and infrastructure adapted to the needs for long-distance electrified transportation. Therefore, different battery-electric truck solutions need to be evaluated to identify an economically, socially, and environmentally friendly way of operating. Consequently, the purpose of this master's thesis is the following:  From a carrier operation perspective, identify different solutions for electrified long-haul transportation and evaluate how cost competitive they are based on triple bottom line. To fulfill this purpose the study was divided into two steps, where the first one was to, through literature and interviews, identify different solutions for electric long-haul transportation and external parameters affecting these solutions. The parameters and solutions were then combined with different distances into focus cases. The second step consisted of identifying both internal and external cost drivers, which were used to create a cost model that considered environmental, economic, and social sustainability. The cost model was then used to evaluate the different focus cases to determine their competitiveness. The solutions were based on wire charging, a 300-, 450-, or 624 kWh battery, and were operated either through trailer swap or point-to-point. The external parameters that were the most important ones were battery degradation, the electricity market, and prerequisites for effective logistics. These were all combined into focus cases which were evaluated on the distances 300-, 400-, 500-, and 600 km. The cost model that was used included both internal and external costs to cover the economic, environmental, and social perspectives in the evaluation. To evaluate the focus cases and be able to compare it to a diesel solution the model considered the costs that differ between a battery electric truck and a diesel truck, which at an overall level was electricity cost, charging infrastructure, batteries, salary when charging, environmental, and social costs. For the distance of 300 km, the most competitive combination was wire charging, 300 kWh battery, and trailer swap. For the distances 400- and 500 km the best combination was wire charge, 450 kWh battery, and trailer swap. The best solution for 500 km was wire charge, 624 kWh battery, and trailer swap. The conclusion is, from a carrier operation perspective, that the most competitive solution to use is based on trailer swap, including a battery with a capacity that is adapted to the distance where the batteries can be charged through wire charging at a charger with a high utilization factor. Finally, for shorter distances, a battery electric truck is cost-competitive against a diesel truck. However, at longer distances a battery electric truck's competitiveness in comparison to a diesel truck gets worse, but at all distances the battery electric truck solution is both socially and environmentally beneficial in comparison to a diesel alternative.
12

Analysis and Comparison of System Performance Using Different Modulation Schemes for Long-Haul Optical Systems and Fiber-To-The-Home Passive Optical Networks

Zhu, Xianming 08 1900 (has links)
<p> Analytical expressions for the propagation impairments due to various noise sources in long-haul optical systems and fiber-to-the-home passive optical networks have been obtained. Extensive comparison has been made in this thesis for systems based on different modulation formats, and the advantage of one over the other is clearly stated.</p> <p> For long-haul fiber optical communication systems with inline amplifiers, we have studied the statistical properties of various noise sources in systems based on differential phase-shift keying (DPSK) such as the linear phase noise induced by the amplifier spontaneous emission (ASE) noise, the intra-channel four-wave mixing (IFWM) and the nonlinear phase noise induced by the interplay between ASE noise and fiber Kerr nonlinearity. The error probability of the system based on DPSK is evaluated semi-analytically. In addition, the error probability of the system based on on-off keying (OOK) is calculated taking into account the effects of ASE noise, and the intra-channel nonlinearities such as IFWM and intra-channel cross-phase modulation (IXPM). Comparison of the performance of systems based on DPSK and OOK is made thereafter.</p> <p> For fiber-to-the-home passive optical networks without inline active photonic devices, different modulation formats have been examined for the downstream and upstream data to enable full-duplex transmission. The statistical properties of Rayleigh backscattering in single-source bi-directional optical systems have been studied including the effects of the high speed external modulation signal and the laser phase noise for systems based on DPSK and OOK. The error probabilities for systems using OOK/OOK topology and DPSK/OOK topology for downstream/upstream transmission have been evaluated and compared.</p> <p> In addition, the interplay of the amplifier spontaneous emission noise, fiber nonlinearity and dispersion has been examined starting from the nonlinear Schrödinger equation on the receiver current fluctuation. The variance of the current noise has been evaluated analytically using the two dimensional perturbation theory.</p> / Thesis / Master of Applied Science (MASc)
13

Analysis and Design of Long Haul Fiber-Optic Communication Systems

Yang, Dong 08 1900 (has links)
<p> This thesis deals with the limiting factors in the design of a long-haul fiber-optic communication system, and the techniques used to suppress their resulting impairments. These limiting factors include both linear and nonlinear effects, such as fiber chromatic dispersion and the Kerr nonlinearity, and the modulator-induced nonlinearity. </p> <p> In Chapter 3, the conditional probability density function (PDF) of the received elect rical signal given transmitted bit '1 '/'0' for a coherent fiber-optic transmission system based on binary phase shift keying (BPSK) is mathematically derived. Both amplified spontaneous emission (ASE) noise and fiber nonlinearity are taken into account . The results show that the conditional PDF of given bit '1' or '0' is asymmetric when intrachannel four-wave mixing (IFWM) is dominant, while it becomes nearly symmetric when the variance of ASE is much larger than that due to IFWM. The standard deviation of the received signal is calculated analytically. The system parameters, including optimum dispersion map and pre-compensation ratio, are optimized by analytically calculating variance of IFWM. Significant computation efforts can be saved using this approach as compared to full numerical simulations of the nonlinear Schrodinger equation, without losing much accuracy. </p> <p> In Chapter 4, an improved 4-f time-lens configuration is proposed. Fourier transform (FT) and inverse Fourier transform (IFT) can be realized using time lenses such that there is no need for time reversal at the end. A typical 4-f configuration consists of two 2-f systems and a temporal filter. The first 2-f system consisting of a time lens and two dispersive elements produces the Fourier transform (FT) of the input signal. The temporal filter modifies the spectrum. The next 2-f system produces the inverse Fourier transform (IFT). A wavelength division demultiplexer and a higher-order dispersion compensator based on 4-f configuration are numerical implemented. One of the advantages of the time-lens-based temporal filtering technique is that the transfer function of the temporal filter can be dynamically altered by changing the input voltage to the temporal filter (amplitude/phase modulator) and therefore, this technique could be used for dynamic switching and multiplexing in optical networks. </p> <p> In chapter 5, a direct-detection optical orthogonal frequency division multiplexing (DD-0-0FDM) is realized using time lenses. Typically, in OFDM systems, discrete Fourier transform (DFT) is used at the transmitter and inverse discrete Fourier transform (IDFT) is used at the receiver. In this chapter, it is proposed to use continuous Fourier transform (FT) and inverse Fourier transform (IFT) using time lenses that replace DFT and IDFT in the electrical domain. The third- and higher-order dispersive effects can be considerably reduced using the proposed DD-0-0FDM scheme. </p> <p> In Chapter 6, a coherent optical orthogonal frequency division multiplexing (OFDM) (C0-0-0FDM) scheme using time lenses is analyzed. The comparison of performance between the proposed scheme and the conventional optical OFDM scheme using fast Fourier transform (FFT) and inverse FFT in the electrical domain is made. Both the Mach-Zehnder modulator (MZM) induced and fiber induced nonlinearities are investigated. Results show that the time-lens-based C0-0-0FDM performs almost the same as the FFT-based C0-0-0FDM when the message signal launched to MZM is low so that MZM operates in the linear region. The nonlinearity of MZM degrades the performance of FFT-based C0-0-0FDM drastically when the power of message signal becomes sufficiently large, but only has negligible impact on the time-lens-based C0-0-0FDM. A periodical driving voltage has been proposed to set up the time lens such that the maximally required driving voltage level is kept low within the time frame. The advantages using the time-lens-based C0-0-0FDM are that (i) FT can be done in optical domain almost instantaneously, whereas the FFT in digital domain is slow and requires significant computational efforts, (ii) optical domain Fourier transform has a large bandwidth (~THz) and therefore, FT /IFT can be performed at a large symbol rate. </p> <p> In Chapter 7, the digital backward propagation (DBP) has been studied both in orthogonal frequency-division multiplexing ( OFDM) and single-carrier (SC) fiber-optic transmission systems. 16 quadrature amplitude modulation (QAM) is used for both systems with the bit rate of 100 Gbjs. The results show that OFDM and SC with Nyquist pulses (SC-Nyquist) have a superior performance as compared to SC with raisedcosine pulses (SC-NRZ) when the DBP is used. The impact of electrical filter bandwidth and nonlinear phase/amplitude noise has also been investigated. The performance of perfect-BP-based OFDM/SC initially improves when the electrical filter bandwidth increases at high signal-to-noise ratio (SNR). The comparison of the effects of nonlinear phase/amplitude noise among OFDM, SC-Nyquist and SC-NRZ systems is made and it is shown that SC-NRZ systems significantly suffer from the effects of nonlinear phase/amplitude noise, which explains the performance advantage of OFDM/SC-Nyquist over SC-NRZ when the DBP used. </p> / Thesis / Doctor of Philosophy (PhD)
14

Education Resource Guide: Jeff Kinney’s ‘The Long Haul’

Lyons, Reneé C. 01 January 2017 (has links) (PDF)
This Education Resource Guide includes discussion questions, as well as activities regarding the following three topics related to Diary of a Wimpy Kid: The Long Haul.
15

Advanced Signal Processing for Fiber-Optic Communication Systems Scaling Capacity Beyond 100 Tb/s / 光ファイバ通信システムの100 Tb/s容量限界の克服へ向けた信号処理技術

Shibahara, Kohki 25 September 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第20740号 / 情博第654号 / 新制||情||113(附属図書館) / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 守倉 正博, 教授 大木 英司, 教授 梅野 健 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
16

TRUE UNMANNED TELEMETRY COLLECTION USING OC-12 NETWORK DATA FORWARDING

Bullers, Bill 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The cost of telemetry collection is significantly reduced by unmanned store and forward systems made possible using 622MHz OC-12 networks. Networks are readily available to telemetry system architects. The in-band control of remote unmanned collection platforms is handled through a Java browser interface. Data from many telemetry channels are collected and temporarily stored on a digital disk system designed around the OC-12 network. The I/O, storage, and network components are configured, set, and initialized remotely. Recordings are started and stopped on command and can be made round-the-clock. Files of stored, time stamped data are delivered at the rate of OC-12 to a distribution center.
17

Alocação dinâmica de recursos: aplicação ao transporte rodoviário de cargas em longa distância. / Dynamic resource allocation: application to long haul freight transportation.

Lima Filho, Antonio Martins 13 May 2011 (has links)
O planejamento operacional de um sistema de transporte de longa distância implica resolver um problema de otimização de rede dinâmica, visando a efetuar, de forma eficaz e eficiente, o atendimento às demandas de cargas, utilizando a capacidade de transporte disponível. A metodologia de solução proposta utiliza a abordagem de Rede de Filas Logísticas, a qual substitui o processo de otimização global da rede (usualmente utilizando Programação Linear Inteira) por um modelo de Programação Dinâmica Estocástica, Aproximada e Adaptativa, que permite a resolução de uma série de subproblemas delimitados no tempo, reduzindo sensivelmente a quantidade de variáveis envolvidas. Este método permite a utilização de modelos matemáticos mais realistas em horizontes de planejamento mais amplos. O presente trabalho estende os modelos encontrados na Literatura, aplicando o método a problemas de maior complexidade, incluindo a consideração de frotas heterogêneas de veículos, janelas de início de atendimento, utilização de terceiros transportadores e penalidades pelo não atendimento das demandas. São apresentados exemplos de problemas experimentais submetidos com sucesso à técnica desenvolvida. O trabalho inclui ainda o delineamento de um Sistema de Apoio à Decisão incorporando a metodologia proposta. / Operational planning of a long haul transportation system implies to solve a dynamic network optimization problem, aiming to perform the freight movements in an efficient and effective way, while utilizing the available transportation capacity. The proposed solution methodology utilizes the Logistic Queueing Network approach, replacing the network global optimization process through Integer Linear Programming by a model of Stochastic, Approximate and Adaptive Dynamic Programming, which allows the resolution of a sequence of sub- problems delimited in time, strongly reducing the quantity of variables involved. This method allows the utilization of more realistic mathematical models in a broader planning horizon. The research extends models found in the literature to solve more complex problems, including the consideration of heterogeneous fleet of vehicles, time windows, third party vehicles and penalties for not attendance of demands. Experimental problems solved successfully with the developed technique are presented. The work also presents the delineation of a Decision Support System incorporating the proposed methodology.
18

Frontiers of optical networking technologies: millimeter-wave radio-over-fiber and 100g transport system for next-generation high-data-rate applications

Hsueh, Yu-Ting 04 April 2012 (has links)
The enabling technologies and the issues of next-generation millimeter-wave wireless access network and 100G long-haul optical transport network were developed and identified. To develop a simple and cost-effective millimeter-wave optical-wireless system, all-round research on the technical challenges of optical millimeter-wave generation, transmission impairments compensation, and simple base station design were discussed. Several radio-over-fiber systems were designed to simultaneously deliver multi-band wireless services on a single optical infrastructure, enabling converged system control and quality maintenance in central office. For the 100G optical transport network, the issues related to successful implementations of transmitter, fiber link, and receiver of a 112-Gb/s polarization-division multiplexing-quadrature phase shift keying (PDM-QPSK) system were comprehensively explored. The experimental results based on the constructed 112-Gb/s testbed indicated that careful dispersion management can effectively increase nonlinearity tolerance. Furthermore, the special emphasis on the two impairments of the 100G network with reconfigurable optical add-drop multiplexers: passband narrowing and in-band crosstalk, was studied. The results demonstrated that these impairments can be readily predicted with proper experimental and simulation efforts.
19

Alocação dinâmica de recursos: aplicação ao transporte rodoviário de cargas em longa distância. / Dynamic resource allocation: application to long haul freight transportation.

Antonio Martins Lima Filho 13 May 2011 (has links)
O planejamento operacional de um sistema de transporte de longa distância implica resolver um problema de otimização de rede dinâmica, visando a efetuar, de forma eficaz e eficiente, o atendimento às demandas de cargas, utilizando a capacidade de transporte disponível. A metodologia de solução proposta utiliza a abordagem de Rede de Filas Logísticas, a qual substitui o processo de otimização global da rede (usualmente utilizando Programação Linear Inteira) por um modelo de Programação Dinâmica Estocástica, Aproximada e Adaptativa, que permite a resolução de uma série de subproblemas delimitados no tempo, reduzindo sensivelmente a quantidade de variáveis envolvidas. Este método permite a utilização de modelos matemáticos mais realistas em horizontes de planejamento mais amplos. O presente trabalho estende os modelos encontrados na Literatura, aplicando o método a problemas de maior complexidade, incluindo a consideração de frotas heterogêneas de veículos, janelas de início de atendimento, utilização de terceiros transportadores e penalidades pelo não atendimento das demandas. São apresentados exemplos de problemas experimentais submetidos com sucesso à técnica desenvolvida. O trabalho inclui ainda o delineamento de um Sistema de Apoio à Decisão incorporando a metodologia proposta. / Operational planning of a long haul transportation system implies to solve a dynamic network optimization problem, aiming to perform the freight movements in an efficient and effective way, while utilizing the available transportation capacity. The proposed solution methodology utilizes the Logistic Queueing Network approach, replacing the network global optimization process through Integer Linear Programming by a model of Stochastic, Approximate and Adaptive Dynamic Programming, which allows the resolution of a sequence of sub- problems delimited in time, strongly reducing the quantity of variables involved. This method allows the utilization of more realistic mathematical models in a broader planning horizon. The research extends models found in the literature to solve more complex problems, including the consideration of heterogeneous fleet of vehicles, time windows, third party vehicles and penalties for not attendance of demands. Experimental problems solved successfully with the developed technique are presented. The work also presents the delineation of a Decision Support System incorporating the proposed methodology.
20

Surf the roads? : An interview study aiming to investigate truck driver’s needs for a web browser in the truck cab

Johansson, Regina January 2011 (has links)
Long haul drivers spend a lot of time in their trucks which consequently serves as both a work place and a second home. The Internet, and communication and information technology can be used for both personal uses by the drivers, and lead to major savings for the haulage firms and provide high level service to the customers. This study investigates what needs long haul drivers have for using the Internet in their trucks, and which devise that best would suit their needs. A questionnaire study was held including 35 drivers, and an interview study including 30 drivers. The results show that almost all drivers want to perform work related tasks through the Internet, and several of them also want to use personal applications online. Work tasks online needs to be performed during the day, whereas private use of the Internet mostly would take place at nights. Several drivers are positive to an integrated system for using the Internet in the truck, and the study presents a possible concept for such a system, and discusses the results related to present research and applicable theories.

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