Engineering Science - Theses, Dissertations, and other Required Graduate Degree Essays

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A stand-alone adaptive corrosion protection system (ACPS) in various corrosive environments

Author: 
Date created: 
2019-07-26
Abstract: 

A novel approach to corrosion monitoring and protection is investigated in different corrosive environments. The standalone Adaptive Corrosion Protection System (ACPS) works in a feedback loop to monitor the corrosion status and protect the target metal. Experiments in different corrosive mediums are carried out using a new stand-alone ACPS unit. A comparative study of the ACPS with the standard Impressed Current Cathodic Protection (ICCP) is done in corrosive mediums at different temperatures and pH. Furthermore, a miniature transmission tower grillage structure buried in the soil is protected using the ACPS. The variations of the electrochemical parameters in different environments are studied and correlated with the macro-environment data. Dynamic ACPS can optimize power consumption by updating the protection parameters at a user-defined interval. Unlike the standard ICCP, the adaptive corrosion protection mechanism is a current-sourced system that effectively monitors and optimally protects the target structure.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Bozena Kaminska
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.

Applications of fireworks-based evolutionary algorithms for computationally challenging network problems

Author: 
Date created: 
2019-06-04
Abstract: 

This thesis covers two types of contributions: formulation of network optimization problems and algorithms to solve these optimization problems. We propose resource assignment problem in Internet of Things network (IoTN) with three nodes: IoT, core cluster node (CCN) and base station (BS). The assignment of resources, such as CPU and memory, from IoTs to CCNs, and CCNs to BSs is a challenging task. The objective of the problem is to minimize the weighted sum of computational power at CCNs and transmission power between IoTs-CCNs and CCNs-BSs radio connections. We also propose a broadband wireless network (BWN) wherein the planning of BSs, relay stations (RSs), and their connections to subscribers minimizes the overall (i.e., weighted sum of the hardware and operational) cost of the network and reformulate a virtual machine (VM) placement to minimize power consumption in a datacenter. The (re)formulated problems are integer programming problem and finding optimal solutions for these problems by using exhaustive search is not practical due to demand of high computing resources. The practical approach is to minimize power in IoT network and VM placement, and plan broadband wireless network using population-based heuristic algorithms. We propose swarm intelligence-based algorithms, that is, two versions of the discrete fireworks algorithm (DFWA) and its variants. The performance of these new algorithms is compared against the low-complexity Biogeography-based Optimization (LC-BBO) algorithm, the Discrete Artificial Bee Colony (DABC) algorithm, and the Genetic Algorithm (GA). Our simulation results and statistical test demonstrate that the proposed algorithm can comparatively find good-quality solutions with moderate computing resources.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Daniel C. Lee
Jiangchuan Liu
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Towards an assistive vestibular stimulation and brain monitoring using a two-channel in-ear EEG system for fine motor enhancement

Author: 
Date created: 
2019-06-03
Abstract: 

The thesis focused on the development of an assistive device employing a galvanic vestibular stimulation (GVS) and brain monitoring platform through in-ear electroencephalography (EEG) system that aims to improve the user’s fine motor skills. The effect of noisy GVS on fine motor skills in healthy subjects was investigated and results showed that simultaneous GVS delivery statistically improved the tracking performance and may be beneficial in improving sensorimotor performance during a fine motor task. A two-channel in-ear EEG system was used for user-state monitoring during performing such a task and results demonstrated the feasibility of using the ear-worn wearable for detecting mental workload induced through a visuomotor task. Future work requires integrating the two components together where electrical stimulation can be reliably delivered and triggered by monitoring user’s mental state through an in-ear EEG system so that the two subsystems work in a closed-loop manner coherently.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Carlo Menon
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.

Biological cell trap arrays with applications to extraordinary optical transmission based immunobiosensing assays

Author: 
Date created: 
2019-05-09
Abstract: 

This thesis’ work is part of a multi-disciplinary project developing a novel immunobiosensing (IBS) platform to monitor antibody (Ab) production by specific cells trapped in a micromachined slide. This platform consists of two subsystems, the micromachined slide featuring the cell traps and the IBS slide integrated with the traps to gauge the affinity with which Ab(s) secreted by specific trapped cells bind an immobilized target antigen (Ag). This thesis’ primary contributions involve the design, fabrication, and experimental testing of multiple cell trap generations—including their integration with co-designed IBS slides. Hydrodynamic flows and sedimentation under gravity are used to trap cells, as they are gentler and require fewer components than other methods. Hydrodynamic flows that guide cells into cup-based traps in enclosed microfluidic channels are investigated. However, their enclosed nature complicates removing extraneous untrapped cells, selectively retrieving trapped cells, and device cleaning between experiments. An open system involving arrays of microwell-(MW)-based traps are used for all subsequent traps. Multiple generations of MW traps and co-designed IBS slides are presented, with each generation refined to further streamline alignment and examination via optical microscopy. Statistical analyses of the observed distribution of trapped cells in the MWs confirm that sedimentation is Poisson distributed, and further suggest that a zero-inflated Poisson (ZIP) function serves as a superior model. This thesis shows that cells can be trapped into an open array of MW traps subsequently aligned with an IBS slide to gauge the affinity with which cell-secreted Ab(s) bind a target Ag. Further refinement to the Extraordinary Optical Transmission (EOT)-based IBS slide used in this thesis is required to achieve Ab-Ag binding detection at the desired single cell/trap level and to improve the IBS slide re-usability. Integration of the traps with a different IBS subsystem is also a possibility. As potential future work, it is proposed that a micropipette needle be used to obtain a revised single cell/trap distribution prior to IBS slide integration and to retrieve the cells of interest selectively.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Bonnie L. Gray
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Simulation of SFU Wi-Fi using Riverbed Modeler

Author: 
Date created: 
2019-04-24
Abstract: 

Pervasive in the workplace, the home, educational institutions, café, airports, and street corners, wireless networks are now one of the most important access network technologies on the Internet today. The IEEE has standardized the 802.11 protocol for wireless local area networks. This project involves the study of the SFU wireless LAN to understand the problem of the slow wireless network (e.g. problems with top hat quizzes, congestion of devices, etc.).The wireless profile in the academic quadrangle area in various classrooms(AQ3181, AQ3182) and hallways will be studied. The Xirrus WiFi inspector and WirelessMon will be used to check the Wi-Fi network and to gather information about the wireless access point(signal strength, data rate, sent rate, etc.). The scenario of the lecture halls with a high-density network will be simulated in the Riverbed modeler to find out the network issues and the solution for the same.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Ash M Parameswaran
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Project) M.Eng.

Integrated voltage current converter and current source inverter drive system for three phase AC machines

Author: 
Date created: 
2019-04-11
Abstract: 

This project is focused on developing a current source inverter (CSI) motor drive system that can be used for a variety of electrical vehicle applications. Voltage source inverters (VSIs) were the primary option for most inverter applications. Generally, VSIs have a number of issues such as larger inverter dimensions, shorter lifetime, and higher cost. A VSI requires a large and costly DC bus capacitor, which also contributes to inverter reliability issues. CSIs are the possible solutions to eliminate the aforementioned problems as they do not need a large DC bus capacitor. Instead, they utilize three small AC filter capacitors and one energy storage component (inductor). In addition to the reduced cost and size, CSIs have several other significant advantages compared to VSIs, including increased reliability and dependability, higher and more stable power suitable for changes in the AC motor speed, and greater motor efficiency and lifespan. This report discusses two of the main components in developing a state-of-the-art CSI drive system. First, the design of the voltage-current (V-I) converter or the controlled current source is presented. Second, the development of a three-phase DC/AC CSI inverter is explained. The V-I converter and the CSI were developed separately, they were integrated and tested for motor or generator operations. Both components of the inverter system are designed and developed using the Matlab/Simulink environment. The system includes a motor or generator load, a three-phase inverter incorporating the space-vector Pulse Width Modulation algorithm. All simulation results are analyzed based on the three phase output voltage and current waveforms.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Craig Scratchley
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Project) M.Eng.

Vapochromic coordination polymer immobilization techniques for ammonia sensors with applications to power transformers

Author: 
Date created: 
2019-04-16
Abstract: 

Ammonia detection is important for many applications in the biomedicine, agriculture, and automotive industries. Sensing of ammonia is also crucial in determining the health of power transformers as the presence of ammonia indicates a breakdown in a transformer’s insulating materials. Current methods of gas analysis for detecting ammonia in such applications are costly, complicated, and time consuming. This thesis is concerned with the use of vapochromic coordination polymers (VCPs), which are in this case fluorescence-based gas sensitive polymers, whose emission spectrum changes upon the binding of target gases, e.g., ammonia. VCP materials have shown great promise in ammonia detection due to their superior fluorescence response and selectivity to ammonia but require immobilization to enable their use as a sensor surface. The work presented in this thesis examines several different immobilization techniques for VCPs to create a new class of ammonia sensors. The first immobilization technique explored involves creating a sheet of post arrays in polydimethylsiloxane (PDMS) to trap and adhere the VCPs to the sensing surface. We show that as the shape of the top of the post arrays is changed (e.g. from simple post to mushroom-shaped caps), the sensitivity of the sensing surface changes. Ammonia detection in the amount of 5 ppm is possible with the most pronounced mushroom shaped posts. The second immobilization method involves dissolved polylactic acid (PLA) mixed with VCPs that are deposited on a PLA substrate, resulting in nanoporous membranes (NPMs) that immobilize the VCP. This technique results in ammonia detection of 5 ppm based on available gas concentrations and reveals that a mix ratio of PLA to VCP of 12% wt. to 88% wt. results in a sensor surface with the highest degree of reversibility. This second immobilization technique also makes a sensor surface that is able to directly detect ammonia dissolved in fluids. Because of the ability of multi-phase gas detection with this immobilization technique we determine that it is the more promising of the two immobilization methods. We explore the application of both immobilization methods in the creation of a sealed micro-fluidic ammonia sensor. Our prototypes use a 3D printed cyclic olefin copolymer (COC) micro-fluidic cell, where COC is employed due to its exceptional optical properties and chemical inertness. These sensor cells detect ammonia both in gas and dissolved in fluids (transformer oil) but are limited in a detection of 1,000 ppm using available gas concentrations for testing.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Bonnie Gray
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.

Advances in slot element and array design

Author: 
Date created: 
2019-03-27
Abstract: 

The slot antenna is one of the simplest types of antennas, being the complement of the most fundamental element, the dipole. Its use, particularly in array configurations, remains an active area of research. The reduced electric current density, relative to the dipole, makes it an extremely efficient element at higher frequencies where the ohmic loss, in even the best conducting metals, becomes important. The slot is naturally suited to cavity or hollow waveguide excitation making an array with an inherent low-loss feed for low-loss elements, and capable of high aperture efficiency. On the practical side, the cavity- or waveguide- slot array can be conveniently realized on a robust all-metal sandwich structure. All these advantages make it one of the best array antenna concepts, and the best for high-frequency applications. Newer generations of wireless communication systems continue to move to higher frequencies for physically smaller antennas, and to electrically larger arrays for adaptive beamforming. At the time of writing, frequencies of particular interest are from 6GHz in present systems to mm-wave (30GHz to 300GHz) in emerging systems. These frequencies typically mean high ohmic losses in the antennas and their feeds. Slot antennas are therefore an obvious candidate design for future systems. This dissertation presents advances in the design of waveguide slot arrays, ranging from a new crossed slot element for dual polarization to new on-chip array concepts. In particular, a new design for a dual-band, dual-polarized, shared-aperture slot array is developed for synthetic aperture radar, but the design also has applications in communications. The triangle waveguide is a simpler structure than the usual rectangular shape, and new slot arrays, requiring new solutions to the triangular waveguide, are also developed. A major motivation is their suitability for on-chip deployment using a MEMs self-assembly technique.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Rodney G. Vaughan
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Adaptive corrosion protection system for smart-grid applications

Date created: 
2018-12-13
Abstract: 

Being one of the popular methods over decades, the utilization of the cathodic protection system is proven to be cost-effective in some cases but demands constant observation and monitoring of the corrosion status. Therefore, adaptive corrosion protection system (ACPS) performs better since It always monitors the corrosion status at user-defined intervals and the ACPS adapts the changes of the target metal structure to provide protection against corrosion. In this project, my role is to understand the theoretical concept and a practical case study of the protection system behaviour including the analysis and improvement of the experimental performances. The project works are evolved around three different sections of the ACPS which are firmware, interface and hardware. The optimum goal is to validate the protection system to be more robust, energy efficient and compatible for any kind of future integration.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Bozena Kaminska
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Project) M.Eng.

Constructions of high-performance face recognition pipeline and embedded deep learning framework

Author: 
Date created: 
2018-06-28
Abstract: 

Face recognition has been very popular in many research and commercial studies. Due to the uniqueness of human faces, a robust face recognition system can be an alternative to biometrics such as the fingerprint or eye iris recognition in security systems. Recent development in deep learning contributed to many of the success in solving difficult computer vision tasks, including face recognition. In this thesis, a thorough study is presented to walk through the construction of a robust face recognition pipeline and to evaluate the components in each stage of the pipeline. The pipeline consists of four components, face detection module, face alignment module, metric space face feature extraction module, and feature identification module. Different implementations of each module are presented and compared. The performance of each implementation of the system is evaluated on multiple datasets. The combination of a coarse-to-fine convolutional neural network (CNN) based face detection, geometric-based face alignment and discriminative features learning with additive angular margin method are found to achieve the highest accuracies in all datasets. One drawback of this face recognition pipeline is that it consumes a lot of computational resources, making it hard to be deployed on embedded hardware. It would be beneficial to develop a method that allows advanced deep learning algorithms to be run on resource-limited hardware, such that many of the existing devices can become intelligent with low cost. In this thesis, a novel lapped CNN (LCNN) architecture that is suitable for resource-limited embedded systems is developed. The LCNN uses a divide-and-conquer approach to apply convolution to a high-resolution image on embedded hardware. The LCNN first applies convolution to sub-patches of the image, then merges the resulting outputs to form the actual convolution. The resulting output is identical to that of applying a larger-scale convolution to the entire high-resolution image, except that the convolution operations on the sub-patches can be processed sequentially or parallelly by resource-limited hardware.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Jie Liang
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) M.A.Sc.