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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

The Use of Positioning Systems for Look-Ahead Control in Vehicles / Användning av positioneringssystem för prediktiv reglering av fordon

Gustafsson, Niklas January 2006 (has links)
<p>The use of positioning systems in a vehicle is a research intensive field. In the first part of this thesis an increase in new applications is disclosed through a mapping of patent documents on how positioning systems can support adaptive cruise control, gear changing systems and engine control. Many ideas are presented and explained and the ideas are valued. Furthermore, a new method for selective catalytic reduction (SCR) control using a positioning system is introduced. It is concluded that look-ahead control, where the vehicle position in relation to the upcoming road section is utilized could give better fuel efficiency, lower emissions and less brake, transmission and engine wear.</p><p>In the second part of this thesis a real time test platform for predictive speed control algorithms has been developed and tested in a real truck. Previously such algorithms could</p><p>only be simulated. In this thesis an algorithm which utilizes model predictive control (MPC) and dynamic programming (DP) been implemented and evaluated. An initial comparative fuel test shows a reduction in fuel consumption when the MPC algorithm is used.</p>
12

Topography based fan control for heavy trucks / Topografibaserad kylfläktstyrning för tunga fordon

Lerede, Niclas January 2009 (has links)
This thesis is a study of how cooling fan control can be improved by using road topography information. Two such controllers are presented, one that uses information available in vehicles produced today, and one that combines GPS-information with digital topographic maps to use information about the road ahead of the vehicle. Simulations show that significant energy savings can be obtained, especially during warm conditions and hilly roads. Compared to conventional fan controllers, energy consumption can be cut by up to three quarters. Moreover, this is possible without any hardware redesign.
13

The Use of Positioning Systems for Look-Ahead Control in Vehicles / Användning av positioneringssystem för prediktiv reglering av fordon

Gustafsson, Niklas January 2006 (has links)
The use of positioning systems in a vehicle is a research intensive field. In the first part of this thesis an increase in new applications is disclosed through a mapping of patent documents on how positioning systems can support adaptive cruise control, gear changing systems and engine control. Many ideas are presented and explained and the ideas are valued. Furthermore, a new method for selective catalytic reduction (SCR) control using a positioning system is introduced. It is concluded that look-ahead control, where the vehicle position in relation to the upcoming road section is utilized could give better fuel efficiency, lower emissions and less brake, transmission and engine wear. In the second part of this thesis a real time test platform for predictive speed control algorithms has been developed and tested in a real truck. Previously such algorithms could only be simulated. In this thesis an algorithm which utilizes model predictive control (MPC) and dynamic programming (DP) been implemented and evaluated. An initial comparative fuel test shows a reduction in fuel consumption when the MPC algorithm is used.
14

A Low-power High-speed 8-bit Pipelining CLA Design Using Dual Threshold Voltage Domino Logic and Low-cost Digital I/Q Separator for DVB-T

Cheng, Tsai-Wen 10 July 2006 (has links)
This thesis includes two topics. One is a low-power high-speed 8-bit pipelining CLA design using dual threshold voltage (dual- Vth) domino logic. The other is a low-cost digital I/Q separator for DVB-T receivers. A high speed and low power 8-bit CLA using dual- Vth domino logic blocks arranged in a PLA-like style with pipelining is presented. According to parallely precharge and sequentially evaluate in a cascaded set of domino logic blocks, transistors in the precharge part and the evaluation part of dual- Vth domino logic are, respectively, replaced by high Vth transistors to reduce subthreshold leakage current through OFF transistors, and low Vth transistors. Moreover, an nMOS transistor is inserted in the precharge phase of the output inverter such that the two-phase dual- Vth domino logic can be properly applied in a pipeline structure. Consequently, the proposed design keeps the advantage of high speed while attaining the effect of low power dissipation. A low-cost digital I/Q separator is presented in the second part of this thesis. Using digital I/Q separator in place of the traditional analog I/Q separator guarantees the design conquer gain and phase mismatch problems between the I and Q channels. The proposed design can berealized by inverters and shifters such that the goal of low cost can be achieved.
15

Utilizing Look-Ahead Information to Minimize Fuel Consumption and NOx Emissions in Heavy Duty Vehicles

Florell, Christoffer January 2015 (has links)
Producing more fuel efficient vehicles as well as lowering emissions are of high importance among heavy duty vehicle manufactures. One functionality of lowering fuel consumption is to use a so called \emph{look-ahead control strategy}, which uses the GPS and topography data to determine the optimal velocity profile in the future. When driving downhill in slopes, no fuel is supplied to the engine which lowers the temperature in the aftertreatment system. This results in a reduced emission reduction capability of the aftertreatment system. This master thesis investigates the possibilities of using preheating look-ahead control actions to heat the aftertreatment system before entering a downhill slope, with the purpose of lowering fuel consumption and $NO_x$ emissions. A temperature model of a heavy duty aftertreatment system is produced, which is used to analyse the fuel consumption and $NO_x$ reduction performance of a Scania truck. A Dynamic Programming algorithm is also developed with the purpose of defining an optimal control trajectory for minimizing the fuel consumption and released $NO_x$ emissions. It is concluded that the Dynamic Programming optimization initiates preheating control actions with results of fuel consumption reduction as well as $NO_x$ emissions reductions. The best case for reducing the maximum amount of fuel consumption results in 0.14\% lower fuel consumption and 5.2\% lower $NO_x$ emissions.
16

Fuel Consumption Estimation for Vehicle Configuration Optimization / Bränsleförbrukningssimuleringar för optimering av fordonsspecifikationer

Söderstedt, Fredrik January 2014 (has links)
Fuel consumption is one of the factors that are considered when deciding a vehicle’s optimal specification. In order to swiftly estimate the fuel consumed during real world driving scenarios, a simulation tool has been developed that is well suited for vehicle configuration exploration applications. The simulation method described in this paper differs from the static calculation method currently in use at Scania cv since the dynamic translation of the vehicle is considered, yet the simulation time is kept low. By adopting a more dynamic approach, the estimation accuracy is increased and simulation of fuel saving technology, e.g. intelli- gent driver support system, is enabled. In this paper, the modeling and implementation process is described. Different approaches is discussed and the choices made during the development is presented. In order to achieve a low simulation time and obtain a good compatability with Scania’s current software application, some of the influencial factors have been omitted from the model or described using simple relations. The validation of the fuel consumption estimation indicates an accuracy within three percent for motorway driving. Utilizing the newly devised simulation tool, a look-ahead cruise controller has been implemented and simulated. Instead of continuously finding the optimal control signals during the driving scenario like most look-aheadcontrollers, a dynamic programming algorithm is used to find a fuel efficient speed profile for the entire route. The speed profile is used as the reference speed for a conventional cruise controller and comparison with another simulation tool indicates that this is a fast and accurate way to emulate a real look-ahead controller.
17

Método do look ahead modificado para estudos de colapso de tensão

Martins, Luís Fabiano Barone [UNESP] 23 February 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-23Bitstream added on 2014-06-13T20:09:48Z : No. of bitstreams: 1 martins_lfb_me_bauru.pdf: 963421 bytes, checksum: 7c1f9175f040c64a63fdf8db9f7a10a1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho foi feita uma análise comparativa entre diferentes escolhas dos pontos utilizados pelo método look ahead na estimação do ponto de máximo carregamento de um sistema elétrico de potência. O Fluxo de Cargo Continuado é utilizado na geração dos pontos de operação utilizados pelo método look ahead e para servir como referência na comparação entre os resultados previstos e o ponto de máximo carregamento real. Uma vez que a exatidão dessa estimativa é fortemente afetada pela escolha desses pontos, o FCC é modificado para fornecer pontos mais adequados para o bom funcionamento do método look ahead. A metodologia proposta é aplicada ao sistema IEEE de 300 barras, os resultados obtidos mostram o seu bom funcionamento / Here we did a comparative analysis between different choices of the points used by the look ahead method for estimating maximum loading point of a power system. The Continued Power Flow (CPF) is used in the generation of operating points used by the look ahead method and to serve as a reference in comparison between the predicted results and the real maximum loading point. Since the accurancy of this estimative is strongly affected by choicen of these points, the CPF is modified to provide the most appropriate for the proper functioning of the method look ahead. The proposed methodology system is applied to IEEE 300 buses, the results have shown its good functioning
18

Optimal Look-Ahead Stopping Rules for Simple Random Walk

Sharif Kazemi, Zohreh 08 1900 (has links)
In a stopping rule problem, a real-time player decides to stop or continue at stage n based on the observations up to that stage, but in a k-step look-ahead stopping rule problem, we suppose the player knows k steps ahead. The aim of this Ph.D. dissertation is to study this type of prophet problems for simple random walk, determine the optimal stopping rule and calculate the expected return for them. The optimal one-step look-ahead stopping rule for a finite simple random walk is determined in this work. We also study two infinite horizon stopping rule problems, sum with negative drift problems and discounted sum problems. The optimal one, two and three-step look-ahead stopping rules are introduced for the sum with negative drift problem for simple random walk. We also compare the maximum expected returns and calculate the upper bound for the advantage of the prophet over the decision maker. The last chapter of this dissertation concentrates on the discounted sum problem for simple random walk. Optimal one-step look-ahead stopping rule is defined and lastly we compare the optimal expected return for one-step look-ahead prophet with a real-time decision maker.
19

Aplicación de last planner en edificaciones multifamiliares

Hinostroza Gutiérrez, Diego Alberto, Manosalva Montesinos, Oscar Omar January 2015 (has links)
A través del programa Maestro (programación macro), se analizará el proceso de planificación Intermedia o Look ahead Planning, sucedido por el plan de trabajo semanal y diario. La planificación intermedia (proceso Look ahead) es una expansión del programa maestro, que genera un programa de trabajo que, pensamos, puede ser ejecutado usando información del estado actual del proyecto y pronósticos sobre la disponibilidad de recursos. Como se sabe, el programa Maestro cubre todas las actividades del proyecto, desde el comienzo hasta el término del mismo. En cambio, la planificación Look ahead abarca intervalos de sólo 4 a 8 semanas, según la complejidad del proyecto, en el futuro con relación a la fecha de la planificación porque la incertidumbre sobre lo que vendrá después deja sin sentido un mayor detalle. El plan de trabajo semanal es la planificación que presenta el mayor nivel de detalle antes de realizar una actividad. Escoger qué trabajo será ejecutado en la próxima semana desde lo que sabemos puede ser hecho, recibe el nombre de asignaciones de calidad. Sólo asignaciones de calidad pueden entrar en un inventario de trabajo ejecutable y posteriormente al plan de trabajo semanal, lo que protege el flujo de producción de incertidumbres, lo que apunta a crear un flujo confiable de trabajo. Para ello se tomó como estudio el edificio multifamiliar las Dalias, donde se explica detalladamente la aplicación de look ahead de la semana 19 donde se realizó el vaciado de losa del sótano 2 y se detalla el análisis de programación semanal con sus posibles restricciones y recursos para poder resolverlas, demostrando con ello que aplicando el Last Planner se maximiza la producción y se minimizan los costos. Through the Master program (macro programming), the mid-term planning or Look ahead Planning, succeeded by the weekly plan and daily work will be analyzed. The intermediate planning (Look ahead process) is an expansion of master program, which generates a work program that we think can be executed using information of the current project status and forecasts on the availability of resources. As is known, the Master program covers all activities of the project from the beginning to the end of it. However, planning ahead Look intervals covers only 4-8 weeks, depending on the complexity of the project in the future in relation to the planning date because uncertainty about what comes next makes it meaningless greater detail. The weekly work plan is the planning that has the highest level of detail before an activity. Choose what work will be executed in the next week from what we know can be done, is called quality assignments. Only quality assignments can enter an inventory of executable work and then to plan weekly work, protecting the flow of production uncertainties, which aims to create a reliable workflow. For this study was taken as the multifamily building Dahlias, which explains in detail the implementation of look ahead to week 19 where the drain basement slab 2 was performed and analysis of weekly programming with the possible restrictions and resources for detailed to resolve them, demonstrating that applying the Last Planner maximizing production and minimizing cost.
20

Método do look ahead modificado para estudos de colapso de tensão /

Martins, Luís Fabiano Barone. January 2011 (has links)
Orientador: André Christovão Pio Martins / Banca: Newton Geraldo Bretas / Banca: Andre Nunes de Souza / Resumo: Neste trabalho foi feita uma análise comparativa entre diferentes escolhas dos pontos utilizados pelo método look ahead na estimação do ponto de máximo carregamento de um sistema elétrico de potência. O Fluxo de Cargo Continuado é utilizado na geração dos pontos de operação utilizados pelo método look ahead e para servir como referência na comparação entre os resultados previstos e o ponto de máximo carregamento real. Uma vez que a exatidão dessa estimativa é fortemente afetada pela escolha desses pontos, o FCC é modificado para fornecer pontos mais adequados para o bom funcionamento do método look ahead. A metodologia proposta é aplicada ao sistema IEEE de 300 barras, os resultados obtidos mostram o seu bom funcionamento / Abstract: Here we did a comparative analysis between different choices of the points used by the look ahead method for estimating maximum loading point of a power system. The Continued Power Flow (CPF) is used in the generation of operating points used by the look ahead method and to serve as a reference in comparison between the predicted results and the real maximum loading point. Since the accurancy of this estimative is strongly affected by choicen of these points, the CPF is modified to provide the most appropriate for the proper functioning of the method look ahead. The proposed methodology system is applied to IEEE 300 buses, the results have shown its good functioning / Mestre

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