Theses

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  • Vapour Diffusion Open Arctic Wall: A Comparison of Moisture Accumulation Potential Versus Other Cellulose Superinsulation Strategies
    Vapour Diffusion Open Arctic Wall: A Comparison of Moisture Accumulation Potential Versus Other Cellulose Superinsulation Strategies
    Superinsulation is becoming increasingly attractive in the construction of energy efficient new homes or energy retrofit projects. By increasing the thermal insulation inside walls, new possible unforeseen building durability issues arise that were otherwise not present during standard 2”x6” construction, as there is less potential for drying. The reduced drying is often attributed to using low permeance materials in the building enclosure. One method to combat the reduced drying potential is to use the highest permeable vapour diffusion open materials for all building enclosure components such as the “Arctic Wall”. The purpose of this study is to determine how the Arctic Wall performs in Fairbanks, Alaska in addition to other climates, and how it also compares with other common vapour diffusion open methods.The results of experimental simulation using WUFI 5.2 hygrothermal software have shown that all vapour diffusion open walls have a potential for condensation that is most dominated by the heating load across the climates that were tested. The Arctic Wall was found to be safe to use in all climates using the tested methods, but still poses a potential risk due to potential condensation due to air leakage. The results of this study have shown that the Arctic Wall performed on par with other vapour diffusion open strategies.
    Variable Length K-SVD: A New Dictionary Learning Approach and Multi-Stage OMP Method for Sparse Representation
    Variable Length K-SVD: A New Dictionary Learning Approach and Multi-Stage OMP Method for Sparse Representation
    The Sparse representation research field and applications have been rapidly growing during the past 15 years. The use of overcomplete dictionaries in sparse representation has gathered extensive attraction. Sparse representation was followed by the concept of adapting dictionaries to the input data (dictionary learning). The K-SVD is a well-known dictionary learning approach and is widely used in different applications. In this thesis, a novel enhancement to the K-SVD algorithm is proposed which creates a learnt dictionary with a specific number of atoms adapted for the input data set. To increase the efficiency of the orthogonal matching pursuit (OMP) method, a new sparse representation method is proposed which applies a multi-stage strategy to reduce computational cost. A new phase included DCT (PI-DCT) dictionary is also proposed which significantly reduces the blocking artifact problem of using the conventional DCT. The accuracy and efficiency of the proposed methods are then compared with recent approaches that demonstrate the promising performance of the methods proposed in this thesis.
    Variable geometry wing-box: toward a robotic morphing wing.
    Variable geometry wing-box: toward a robotic morphing wing.
    The ability to vary the geometry of a wing to adapt to different flight conditions can significantly improve the performance of an aircraft. However, the realization of any morphing concept will typically be accompanied by major challenges. Specifically, the geometrical constraints that are imposed by the shape of the wing and the magnitude of the air and inertia loads make the usage of conventional mechanisms inefficient for morphing applications. Such restrictions have served as inspirations for the design of a modular morphing concept, referred to as the Variable Geometry Wing-box (VGW). The design for the VGW is based on a novel class of reconfigurable robots referred to as Parallel Robots with Enhanced Stiffness (PRES) which are presented in this dissertation. The underlying feature of these robots is the efficient exploitation of redundancies in parallel manipulators. There have been three categories identified in the literature to classify redundancies in parallel manipulators: 1) actuation redundancy, 2) kinematic redundancy, and 3) sensor redundancy. A fourth category is introduced here, referred to as 4) static redundancy. The latter entails several advantages traditionally associated only with actuation redundancy, most significant of which is enhanced stiffness and static characteristics, without any form of actuation redundancy. Additionally, the PRES uses the available redundancies to 1) control more Degrees of Freedom (DOFs) than there are actuators in the system, that is, under-actuate, and 2) provide multiple degrees of fault tolerance. Although the majority of the presented work has been tailored to accommodate the VGW, it can be applied to any comparable system, where enhanced stiffness or static characteristics may be desired without actuation redundancy. In addition to the kinematic and the kinetostatic analyses of the PRES, which are developed and presented in this dissertation along with several case-studies, an optimal motion control algorithm for minimum energy actuation is proposed. Furthermore, the optimal configuration design for the VGW is studied. The optimal configuration design problem is posed in two parts: 1) the optimal limb configuration, and 2) the optimal topological configuration. The former seeks the optimal design of the kinematic joints and links, while the latter seeks the minimal compliance solution to their placement within the design space. In addition to the static and kinematic criteria required for reconfigurability, practical design considerations such as fail-safe requirements and design for minimal aeroelastic impact have been included as constraints in the optimization process. The effectiveness of the proposed design, analysis, and optimization is demonstrated through simulation and a multi-module reconfigurable prototype.
    Variable time domain discretization methodology for molecular dynamics simulation of metallic compounds
    Variable time domain discretization methodology for molecular dynamics simulation of metallic compounds
    The present work proposes a methodology to improve the computational requirements of molecular dynamics simulations while maintaining or improving the fidelity of the obtained results. The most common method of molecular dynamics simulation at present is the multi-force, constant time-step, explicit computation, which advances a single time step at a time to determine the next state of the system. The present work proposes a variable time-step strategy, where a single large simulation is subdivided into multiple time domains which redistribute computational resources where they are needed the most: in areas of higher than average potential or kinetic energy or highly dynamic areas around impurity clusters, void formations and crack propagations. The research focuses on the simulation of metallic compounds, as these form the basis of most common molecular dynamics simulations, and have been very thoroughly investigated over the years, thus providing a very extensive body of work for the purpose of comparison and validation of the proposed methodology. The novel methodology presented in this work allows to alleviate some of the limitations associated with the molecular dynamics methodologies and go beyond traditional scales of simulation. The proposed method has been observed to deliver 5 to 20 percent increase in simulation size domain while maintaining or improving the accuracy and computational cycle time. The benefits were observed to be greater for large simulations with one or more areas of higher than average kinetic or potential energy levels, such as those found during crack initiation and propagation, coating-substrate interface, localized pressure application or large thermal gradient. The large difference allows for very clear prioritization of computational resources for high energy areas and as a result provides for faster and more accurate simulation even with increased domain size. Conversely, this method has been observed to provide little to no benefit when simulating stable systems that are undergoing very slow change, such as (relatively) slow change in ambient temperature or pressure, or otherwise homogeneous internal and external boundary conditions. However, for the majority of applications described above, including coating deposition and additive manufacturing, the proposed methodology will yield substantial increase in both simulation size and accuracy, since in the aforementioned processes kinetic and potential energy gradients across the simulation are typically very significant
    Vehicle Position Tracking Using Kalman Filter And CWLS Optimization
    Vehicle Position Tracking Using Kalman Filter And CWLS Optimization
    Vehicle position estimation for wireless network has been studied in many fields since it has the ability to provide a variety of services, such as detecting oncoming collisions and providing warning signals to alert the driver. The services provided are often based on collaboration among vehicles that are equipped with relatively simple motion sensors and GPS units. Awareness of its precise position is vital to every vehicle, so that it can provide accurate data to its peers. Currently, typical positioning techniques integrate GPS receiver data and measurements of the vehicles motion. However, when the vehicle passes through an environment that creates multipath effect, these techniques fail to produce high position accuracy that they attain in open environments. Unfortunately, vehicles often travel in environments that cause multipath effect, such as areas with high buildings, trees, or tunnels. The goal of this research is to minimize the multipath effect with respect to the position accuracy of vehicles.The proposed technique first detects whether there is disturbance in the vehicle position estimate that is caused by the multipath effect using hypothesis test. This technique integrates all information with the vehicle's own data and the Constrained Weighted Least Squares (CWLS) optimization approach with time difference of arrival (TDOA) technique and minimizes the position estimate error of the vehicle. Kalman filter is used for smoothing range data and mitigating the NLOS errors. The positioning problem is formulated in a state-space framework and the constraints on system states are considered explicitly.The proposed recursive positioning algorithm will be comparatively more robust to measurement errors because it updates the technique that feeds the position corrections back to the Kalman Filter as compared with a Kalman tracking algorithm that estimates the target track directly from the TDOA measurements. It compensates the GPS data and decreases random error influence to the position precision.The new techniques presented in this thesis decrease the error in the position estimate. Simulation results show that the proposed tracking algorithm can improve the accuracy significantly.
    Ventricular fibrillation detection algorithm for automated external defibrillators
    Ventricular fibrillation detection algorithm for automated external defibrillators
    The automatic external defibrillator (AED) is a lifesaving device, which processes and analyzes the electrocardiogram (ECG) and prompts a defibrillation shock if ventricular fibrillation is determined. This project investigates the possibility of developing a Ventricular Fibrillation (VF) detection algorithm based on Autoregressive Modeling (AR Modeling) and dominant poles for the use in AEDs. In particular, the ECG segment is modeled using AR modeling and the dominant poles are extracted from the model transfer function. The dominant pole frequencies were then used in classification based on the distance measure. The potential use of this method to distinguish between VF and Normal sinus rhythm (NSR) is discussed. The method was tested with ECG records from the widely recognized databases of American Heart Association (AHA) and the Creighton University (CU). Sensitivity and specificity for the new VF detection method were calculated to be 66% and 94% respectively. The proposed method has some advantages over other existing VF detection algorithms; it has a high detection accuracy, it is computationally inexpensive and can be easily implemented in hardware.
    Verification of a control systems design for a series resonant converter based on a small-signal model
    Verification of a control systems design for a series resonant converter based on a small-signal model
    The project verifies the performance of a control system designed for a Series Resonant Converter (SRC). A discrete small-signal model of an SRC was derived and used to design the control system. An accurate control system was designed in the frequency domain to eliminate the need for trail-and-error [sic] methods or other time domain methods. A PSPICE simulation of a regulated SRC circuit was used to test the control system. A prototype of the regulated SRC was developed to verify the simulated results. The tests performed demonstrated that the control system design provides a quick response. The tests determined that when a step input is applied to the reference input the control system adjusts the SRC's output voltage to the new reference input value. Also, the control system is able to regulate output load voltage in the presence of sudden load changes.
    Vertical phosphorus migration in biosolids-amended soils : concentrations in soils and leachates.
    Vertical phosphorus migration in biosolids-amended soils : concentrations in soils and leachates.
    The impacts of biosolids land application on soil phosphorus and subsequent transfer to aquatic ecosystems in the condition of the minimal slope were assessed. Soil, representing typical "Non response" Ontario soil, was amended with anaerobically digested biosolids at a rate of 8 tonnes/ha. Over five months, soil samples from two different depths were sequentially fractionated to determine various inorganic and organic phosphorus pools in order to evaluate phosphorus vertical migration within a soil profile. Soil leachate was analyzed for soluble reactive phosphorus and added to the aquariums mimicking receiving surface waters. Water from aquariums was tested for the presence of eutrophication. The results indicated that biosolids application did not significantly affect phosphorus concentrations in soil and did not cause phosphorus vertical migration. The concentrations of soluble reactive phosphorus also were not affected by biosolids. No signs of eutrophication were observed in receiving waters.
    Vertiginous pleasures
    Vertiginous pleasures
    In the opening lines to his unique collection of cinematic art, Italian Movie Posters, Dave Kehr reminds us that "in the final analysis, movie posters are advertisements-in other words, promises made to be broken. But what glorious promises they make" (9)1 In large part this text is dedicated to exploring these very promises, not so much to celebrate the grandeur and bombast of the film poster but to understand the complex processes of interaction that exist between a film, its posters, and their audiences. Of course, the promises that Kehr is referring to are the more or less straightforward ones posters make when they implicitly offer us the chance at experiencing the films they promote as glamorous, adventurous, terrifying, and seductive. In this respect, film posters, like all forms of advertising, seek to create audiences by attaching a fixed social identity to a product that is by its nature polysemic, representing too many things to too many people to be completely represented by any single combination of text and image. Unlike most consumer products however, films are ephemeral in nature, disappearing from view the minute they have been consumed, and like dreams they are only half-remembered by those who have consumed them. Consequently, the relationship between the film and its poster is not quite the same as the relationship between a tangible consumer product and the advertising imagery that sells it. The intangibility of films, in that they are seen only temporarily in the dark and quiet confines of the theatre and our living rooms, make them especially in need of a body, a corporeal vehicle with which they can circulate in the world. In a consumerist culture such as ours, where social relations are structured through the fetishization of commodities, ephemeral products such as films leave consumers needing a tangible emblem, either because they crave owning a piece of what they love or simply to see for themselves whether or not a film is in fact "my kind of movie."
    Vestibular rehabilitation using a virtual environment for driver safety
    Vestibular rehabilitation using a virtual environment for driver safety
    Driving is a necessity of life, and it requires multi-sensory input and processing. Often vestibular impaired patients suffer from dysfunctional sensory input that impairs their driving. Therefore, driver's attention, and egocentric navigation skills are investigated in this project through the use of a spaceball driving simulator.This thesis clarly demonstrates and specifies the steps of implementation of a driving simulator into the spaceball. Driver attention was tested through the use of computer and audio reflex time and was used to analyze the improvement in reaction time. Seat perturbation reflex time test was used to analyze the driver egomotion awareness on the simulator.The experimental results illustrate the improvement in the driving rehabilitation field of reaction time which leads to the conclusion that the visual-proprioceptive virtual driving simulator could provide treatment to the vestibular impaired patients.
    ViC : virtual cadaver - a prototype extendible system for building photorealistic interactive visualizations of human anatomy using game development technology
    ViC : virtual cadaver - a prototype extendible system for building photorealistic interactive visualizations of human anatomy using game development technology
    This thesis presents a Virtual Cadaver system, ViC, which allows users to interactively “cut open” and visualize a highly realistic representation of 3D human anatomy, including skin, muscles, bones, arteries and many other anatomical systems and structures. ViC’s interaction and visualization functionality, coupled with a multi-touch interface, provide real-time cutaway operations using simple and familiar gestures.To support the cutaway feature, ViC’s 3D human anatomy dataset is preprocessed, breaking up the large anatomy system data meshes into smaller, more manageable mesh “fragments”. The shape of each fragment is crafted to support semantically meaningful cutaways while the “granularity” of the fragments supports interaction efficiency. ViC uses game technology to enable highly realistic rendering of human anatomy. Furthermore, ViC’s performance and cutaway capabilities were evaluated on consumer-grade hardware to confirm that real-time interaction and visualization with highly-responsive multi-touch input actions can be achieved.