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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.
1

Instructional Design and Performance Evaluation for Adaptive Learning of Decimal Division on SCORM2004 Compliant LMS

Hsu, Feng-Hsien 29 August 2005 (has links)
The main objective of this research is to adopt SCORM SSS (Simple Sequence Specification) standard to develop an adaptive learning system and to access its effectiveness for adaptive learning. The dependent variable of this research is the learners¡¦ learning outcomes, including three constructs that are the learning performance, satisfaction and learning efficiency. The subjects of this research are two classes with total of 61 students in the fifth grade of elementary school, the experiment group has 31 students, and the control group has 30 students. Experiment learning topic is decimal division in mathematics of primary school. The learning materials are designed by a professional teacher in the field of mathematics domain. The concept map and instructional flow chart were used to guide the content design. The result has found that the adaptive learning not only has the same level of learning performance, but also has a higher learning efficiency comparing with the traditional learning. The contributions of this research are; to provide an exemplification of how to design an adaptive learning course using SCORM SSS compliant LMS; to show the advantage that learners don¡¦t have to strict on a fixed learning path like in a traditional courses; and to demonstrate the potential for those competent students who can use less time to complete normal tasks and hence get chances to explore more in depth knowledge.
2

Active Flight Path Control for an Induced Spin Flight Termination System

Shukla, Poorva Jahnukumar 12 September 2017 (has links)
In this thesis, we describe a method for controlling the cycle-averaged velocity direction of a fixed-wing aircraft in an unpowered, helical descent. While the aircraft propulsion system is disabled, either intentionally or due to a failure, the aerodynamic control surfaces (aileron, elevator, and rudder) are assumed to be functional. Our approach involves two steps: (i) establishing a stable, steady, helical motion for which the control surfaces are not fully deflected and (ii) modulating the aircraft control surfaces about their nominal positions to ``slant'' the helical flight path in a desired direction relative to the atmosphere, whether to attain a desired impact location, to counter a steady wind, or both. The effectiveness of the control law was evaluated in numerical simulations of a general transport model (GTM). / Master of Science / When an unmanned aircraft is near an authorized airspace (a region of space where the aircraft is not authorized to fly) and experiences a failure such as loss of communication with the control tower,or failure of the GPS or propulsion system, then the aircraft is generally put into an aerodynamic flight termination. In this flight termination method, the aircraft propulsion system is switched off and the control surfaces (aileron, elevator and rudder) are fixed to induce a spin in the aircraft causing it to descend in a helical fashion. However, in the presence of external gusts the aircraft might drift into the unauthorized airspace; or once the aircraft is put into spin, one may want to be able to change the impact location to a safer place. To the best of our knowledge, there exist no control strategies to alter the impact location of the aircraft once it is put into spin and while is continues to spin. In this thesis we describe a method to do so. The aircraft impact location is altered by controlling the cycle-averaged velocity direction of a fixed-wing aircraft in an unpowered, helical descent. While the aircraft propulsion system is disabled, either intentionally or due to a failure, the aerodynamic control surfaces (aileron, elevator, and rudder) are assumed to be functional. Our approach involves two steps: (i) establishing a stable, steady, helical motion for which the control surfaces are not fully deflected and (ii) modulating the aircraft control surfaces about their nominal positions to “slant” the helical flight path in a desired direction relative to the atmosphere, whether to attain a desired impact location, to counter a steady wind, or both. The effectiveness of the control law was evaluated in numerical simulations of a general transport model (GTM).
3

Optimal air and fuel-path control of a diesel engine

Yang, Zhijia January 2014 (has links)
The work reported in this thesis explores innovative control structures and controller design for a heavy duty Caterpillar C6.6 diesel engine. The aim of the work is not only to demonstrate the optimisation of engine performance in terms of fuel consumption, NOx and soot emissions, but also to explore ways to reduce lengthy calibration time and its associated high costs. The test engine is equipped with high pressure exhaust gas recirculation (EGR) and a variable geometry turbocharger (VGT). Consequently, there are two principal inputs in the air-path: EGR valve position and VGT vane position. The fuel injection system is common rail, with injectors electrically actuated and includes a multi-pulse injection mode. With two-pulse injection mode, there are as many as five control variables in the fuel-path needing to be adjusted for different engine operating conditions.
4

CONTROL OF OVER-ACTUATED SYSTEMS WITH APPLICATION TO ADVANCED TURBOCHARGED DIESEL ENGINES

Zhou, Junqiang 14 May 2015 (has links)
No description available.
5

Distributed Model Predictive Control with Application to 48V Diesel Mild Hybrid Powertrains

LIU, YUXING 30 September 2019 (has links)
No description available.
6

Systematic Optimization and Control Design for Downsized Boosted Engines with Advanced Turbochargers

Liu, Yuxing 15 October 2014 (has links)
No description available.
7

[en] CONTROL STRATEGIES APPLIED TO GROUND VEHICLES HANDLING PROBLEM IN PRE-DEFINED CLOSED TRAJECTORIES / [pt] ESTRATÉGIAS DE CONTROLE APLICADAS AO PROBLEMA DE DIRIGIBILIDADE DE VEÍCULOS TERRESTRES EM TRAJETÓRIAS FECHADAS PRÉ-DEFINIDAS

FERNANDO HEY 09 October 2008 (has links)
[pt] Apresenta-se o uso das ferramentas lineares de Controle Clássico (Lugar Geométrico das Raízes) e Moderno (Realimentação de Estado e de Saída e Alocação de Pólos) para estabelecer os ajustes dos controladores adotados no problema de acompanhamento de trajetórias em traçados fechados por veículos terrestres, procurando reproduzir o comportamento do ser humano no comando deste tipo de sistema. Os modelos adotados para o veículo são lineares (funções de transferência e matrizes de estado e de entrada), porém a caracterização da trajetória fechada é geometricamente não-linear. Verifica-se deste modo como o projeto de um controle linear satisfaz as condições não lineares associadas. Os conceitos e ferramentas conhecidos são aplicados em diversos tipo de traçados, para diferentes condições do veículo - velocidade, limites de esterçamento, etc - e, a partir das simulações realizadas, são analisadas as características de comportamento do veículo - acelerações, estabilidade, etc - e comparadas as previsões dos projetos lineares com os resultados encontrados. É feita ainda uma breve introdução ao emprego do Controle Ótimo no problema de acompanhamento de traçados, utilizando um modelo bastante simplificado do veículo, e verificando as condições necessárias para se estabelecer a trajetória ótima em um traçado aberto, dado como critério o tempo mínimo para percorrê-lo. / [en] The use of classic and modern linear control tools (root locus and output regulation) is presented to determine the parameters of controllers used to follow a pre-defined closed path, in a way to approach the vehicle behavior and human actions when driving a car. The car is represented by linear models (transfer functions, state-space matrix), but the relation between the car and the closed path is non linear. It is verified how the project of a linear controller deals with the non linear characteristics of the closed loop. The concepts and tools of linear control are applied to some kinds of paths in different vehicle conditions (speed, steering angle limits, etc), and the results of simulations show the characteristics of the car, like accelerations, stability and position on the track. It`s also presented a little introduction to the problem of determine an optimal trajectory to run a corner, given the initial and final velocities and initial and final positions. In this case a very simple model is considered and the solution is based on open paths analysis.
8

Controle de trajetória baseado em visão computacional utilizando o Framework ROS

Oliveira, Leandro Luiz Rezende de 11 November 2013 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-26T12:41:45Z No. of bitstreams: 1 leandroluizrezendedeoliveira.pdf: 11529978 bytes, checksum: 0d088d792c8861423c02cd09cfcdc538 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-26T13:54:24Z (GMT) No. of bitstreams: 1 leandroluizrezendedeoliveira.pdf: 11529978 bytes, checksum: 0d088d792c8861423c02cd09cfcdc538 (MD5) / Made available in DSpace on 2017-04-26T13:54:24Z (GMT). No. of bitstreams: 1 leandroluizrezendedeoliveira.pdf: 11529978 bytes, checksum: 0d088d792c8861423c02cd09cfcdc538 (MD5) Previous issue date: 2013-11-11 / O objetivo do presente trabalho é apresentar o desenvolvimento de um controle de trajetória para robôs móveis baseado em visão computacional, implementado no Framework ROS (Robotic Operating System). O ambiente do futebol de robôs foi utilizado como plataforma de teste da metodologia proposta. Para executar essa tarefa foi desenvolvido um algoritmo para o sistema de visão robótica, capaz de executar a calibração do sistema de captura de imagens e a identificação dos robôs no campo de acordo com a forma e a cor das etiquetas de identificação através da biblioteca OpenCV, a qual é integrada na estrutura fornecida pelo ROS. Os algoritmos elaborados de visão computacional, controle de alto nível e controle de baixo nível foram estruturados conforme as diretrizes do ROS, sendo assim denominados de nós. Os algoritmos de alto nível responsáveis pelo controle de trajetória, tratamento de imagem e controle são executados em um computador desktop ou notebook, ao passo que o algoritmo de baixo nível para controle é executado em uma plataforma Arduino embarcada no robô. O computador ou notebook e a plataforma Arduino embarcadas nos robôs trocam informações entre si de forma distribuída utilizando tópicos que interligam os nós e transmitem mensagens utilizando o padrão Publisher/Subscriber. Ainda é abordado o desenvolvimento do robô diferencial proposto, com seus dispositivos de controle, comunicação e tração. / The goal of this work is to present the development of a path control for mobile robots based on computer vision, implemented in ROS (Robotic Operating System) Framework. The robot soccer environment was used as test platform for the proposed methodology. To accomplish this task was developed an algorithm to the robotic vision system, able to perform the calibration of image capture system and the identification of robots in the field according to the shape and color identification labels through the OpenCV library, which is integrated into the structure provided by ROS. The algorithms developed for computer vision, high-level control and low-level control were structured according to the guidelines of the ROS, therefore called nodes. The algorithms responsible for the high-level path control, image processing and control are performed on a desktop computer or notebook, while the algorithm for low-level control is running on a platforms Arduino embedded in the robots. The computer or notebook and embedded platform Arduino exchange informations among themselves in a distributed manner using topics, interconnecting nodes and transmit messages using the Publisher/Subscriber default. Also is addresses the development of a differential robot proposed, with their control devices, communications and traction.
9

A comparative analysis of Cisco Performance Routing (PfR) and other performance enhancing techniques - Cisco QoS and Path Control

Younas, Muhammad January 2011 (has links)
Eleven years ago Cisco introduced three types of applications on the same converged network and named it AVVID (Architecture for Voice, Video and Integrated Data). In spite of the initial interest and hype surrounding AVVID, the feature was and still is unable to confront problems such as: data priority, load balancing and network congestion. The work in this report addressed these issues within the network. Different Cisco Internetwork Operating System (IOS) methods: routing protocols, Cisco IOS QoS (including LLQ, LFI and Header Compression), Path Control and Cisco Performance Routing (PfR) were all tested to see which feature would work best at enhancing network performance. A practical network was created in which these features were carefully implemented one after another. In every step, the results were observed and recorded and if necessary repeated in order to check their validity. The results for RTT (Round Trip Time) and MOS (Mean Opinion Score) showed that in comparison to Path Control and Cisco IOS QoS (Quality of Service) mechanisms, Cisco PfR was able to generate routes on the fly during times of network congestion. This cannot be achieved with the use of Cisco QoS and Path Control which makes Cisco Performance Routing a far more superior feature. Although the focus of the work was VoIP (Voice over Internet Protocol) data, it is possible to construct a network with any application as Cisco PfR is able to reroute data. Cisco PfR is an easily accessible IOS feature which, once implemented, requires very little updating and maintenance.

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