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

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Design, Fabrication and Testing of Magnetic Composite Polymer Actuators Integrated With Microfluidic Devices and Systems

Author: 
Date created: 
2016-09-27
Abstract: 

Work presented in this thesis demonstrates methods of combining a newly developed magnetic composite polymer (M-CP) with other commonly used polymer microfluidics materials for the creation of complex all-polymer microfluidic systems. To achieve fully integrated microfluidic systems, new fabrication techniques for integration of M-CP structures are developed. Employing the new M-CP material and the novel fabrication techniques, three types of actuators are developed: cilia, flap, and hybrid M-CP/PDMS actuator. All three actuators employ compatible materials, fabrication techniques, and actuation mechanisms. The performance of each of these actuators is characterized for different applications: cilia-based mixers, flap-based valves, and hybrid M-CP/PDMS actuators for applying extracellular stimulation on cell monolayers. The actuators in each of these applications are driven via relatively small external magnetic fields. The M-CP used in these novel actuators is composed of rare-earth magnetic micro-particles (5–10 micrometer) that are embedded in polydimethylsiloxane. The M-CP is patterned into large force, large stroke actuators. The polymer matrix without magnetic particles is employed as the substrate material for passive parts, facilitating integration of the magnetic and non-magnetic materials. The compatible fabrication techniques include a modified soft-lithography technique for hybrid M-CP/PDMS actuators, screen printing via shadow masks for micro-patterning of thin layers of M-CP, and a novel fabrication technique using poly(ethylene glycol) (PEG) as a sacrificial material for the fabrication of ultra-high aspect-ratio and highly flexible M-CP cilia. Microfluidic devices using these actuators show improved performances in their respective fields when compared with existing designs. Microfluidic mixers with 8 cilia show a reduction in mixing time of up to 63 times over diffusion. Flap-based valve arrays effectively switch flows between two microfluidic channels using an array of two valves, and effectively perform as on-off switches for flow control. A valve with a 2.3 mm flap thickness, actuated under an 80 mT magnetic field, is capable of blocking liquid flow at a flow rate of 1 mL/min for pressures up to 9.65 kPa. Microfluidic platforms for stretching/compressing biological cells based on the hybrid M-CP/PDMS actuators achieve large and bi-directional surface deflections. Actuation can be applied cyclically, under both flow and no-flow conditions.

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

Implementation of the Functional Shape Cortical Brain Surface Analysis Pipeline on a High Performance Computing Environment

Date created: 
2016-08-08
Abstract: 

The main organ of the human central nervous system, the human brain, is one of the most complex organs in the human body. The causes of many brain diseases and disorders, such as Alzheimer’s disease, and their ideal treatments are still not fully understood with the current medical technology. With medical imaging techniques such as magnetic resonance imaging (MRI), magnetoencephalography (MEG), and electroencephalography (EEG), the data obtained from these techniques can be used to study and examine brain diseases and disorders. This project focuses on utilizing a surface registration method on multiple brain surfaces to obtain various geometric transformations for brain studies, and the implementation of the analysis pipeline on a high performance computing (HPC) environment. Due to the infeasibility on runtime for performing surface registration between one template brain surface and multiple target brain surfaces, an approach to perform sub-surface extraction on each brain surface and computation on a HPC environment has been employed. This has allowed a significant reduction in runtime and has also allowed the results to be obtained within reasonable time.

Document type: 
Graduating extended essay / Research project
File(s): 
Supervisor(s): 
Mirza Faisal Beg
Karteek Popuri
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Project) M.Eng.

Ion discharge cooling device

Author: 
Date created: 
2016-04-21
Abstract: 

This paper discusses ion wind based on corona discharge. Ion wind generated by corona discharge voltage and an electric field can be used as a cooling device to replace a ventilation fan. Like some prior works done by others, the device is mainly composed of thin wires and blunt brass bars. The wind velocity can reach a value of 1 m/s under 3000 volts. In this report, the relationships between velocity and many parameters have been determined.

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

Performance Comparison of H.264/AVC and HEVC Standards over LTE Networks

Author: 
Date created: 
2015-02-23
Abstract: 

Long Term Evolution (LTE) is a standard for wireless communication developed by the 3rd Generation Partnership Project (3GPP) with an aim to fulfill the requirements defined for the fourth generation (4G) wireless networks. With more than hundred service providers across the globe and around one billion subscribers predicted by the year 2016, LTE is set to become the first true global standard. With the high data rates supported by LTE, improvements like Content Distribution Network (CDN) and increase in router switching speeds, popularity of video streaming services over the mobile networks is set to touch a new high. This popularity provides opportunity to the network operators to increase their revenues, but it also challenges them to provide video streams with minimum desirable quality to their customers. This has led to the emergence of two popular single layer video coding standards namely, H.264/AVC and more recently H.265/High Efficiency Video Coding (HEVC). With LTE being projected as a candidate to fuel the future 4G services, it is desirable to evaluate the performance of these two video coding standards over the LTE networks. The first part of this project tries to evaluate the video quality offered by these two video coding standards over LTE network by studying the impact of delay, distance and number of users in the LTE cell. In the second part of this project we implement a frame dropping mechanism which drops low priority frames of the video encoded with hierarchical B-frame structure when the channel conditions are not ideal, thus providing graceful degradation to the single layer videos. This mechanism tries to exploit the fact that in a video that is encoded using a hierarchical structure, the loss of a frame that belongs to the higher indexed temporal layer of a video has less negative impact on the video quality in comparison to the loss of a frame in the lower indexed temporal layer.

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

Design of Hardware Accelerators with Configurable Pipeline

Author: 
Date created: 
2016-08-22
Abstract: 

In today’s world, people are widely using technology to make their lives more comfortable and better. The development of semiconductors technology is making Integrated Circuits(IC) smaller and smaller in size, thus allowing IC designer to include more and more functionalities in their products. This development of technology has allowed a large diffusion of semiconductor devices in all aspects of human life, leading to the concept of “embedded” computation, described as the practice of including the small processor devices in all spaces of our world, from our houses, to our cars, to even “wearable electronics” that we carry around as we move. In particular, floating point computation (FP) is a feature of computers that, at the price of significant additional hardware complexity and sometimes at the price of result accuracy, provides a much larger range of usable numbers, thus significantly enhancing the flexibility and usability of our computation. The additional hardware complexity imposed by FP units imposed a relevant price in Silicon Area (making the IC more expensive) and especially in terms of power consumption. In turn, energy consumption is a very severe issue in semiconductor technologies: first, it causes unreliability of the IC technology. Secondly, IC energy consumption leads to greenhouse gas emission. Finally, many IC systems are battery operated and high consumption may jeopardize the system usability and/or user experience. One very significant category of embedded processors is that of embedded sensors. Embedded sensors produce relevant quantities of raw data that needs to be adequately classified in order to provide significant information, and Machine Learning is often applied as a strategy for sensor data classification.This MENG project aims at exploring design strategies for low-power FP computation. In the following, we will introduce the design of a hardware FPU unit whose sub-blocks can be programmed to change dynamically the computational speed with the change in the voltage. This enables the FPU to adapt their consumption to the requirement of the environment, offering high performance (and high consumption) whenever needed by the environment, but adapting to low power, low speed mode whenever intensive processing is not necessary.

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

Optimizing the Forces of Climbing Robots

Author: 
Date created: 
2016-07-12
Abstract: 

Climbing robots have the potential to be used in diverse applications, such as cleaning sky scrapers, maintaining of maritime structures, and conducting search and rescues. The focus of this thesis is on optimizing the forces of a climbing robot loitering on vertical surfaces. The optimization is primarily achieved through on minimizing the maximum normal adhesion force on the tips of the legs of a six-legged climbing robot as well as the maximum torque experienced by the joints. In this theses, the model of a six legged robot is simplified into a two dimensional structure with three legs. Furthermore, this simplified robotic model was validated by the use of biomimicry; in which the stance of the ants is analyzed using the same model and verified that their posture indeed minimizes the maximum adhesion on the tips of their legs. The optimal normal adhesion force for a climbing robot is calculated using a closed form solution. For robots with position controlled legs, the effects of different geometrical parameters and the stiffness of the materials, used to build the structure of the robot are investigated with a focus on maximum normal adhesion. Calculation of the forces on the structure uses the Finite Element Method (FEM). For robots with force/torque controlled legs, the effect of geometric parameters, specifically the height and, the length of the robot and the position of the middle leg, are also investigated with emphasis on maximum normal adhesion. The effects of the investigated parameters are summarized and presented as guidelines for the design of climbing robots. Also, the non-linear and non-differentiable problem of minimizing the maximum torque on the joints of the robot, that uses the optimal normal adhesion force on the tips of their legs, is addressed only for robots with force/torque controlled legs. Finally, a transformation that converts the problem into a linear form is presented. The proposed method was found to outperform three other widely used algorithms in terms of speed and accuracy.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Carlo Menon
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Visual-Inertial Sensor Fusion for Tracking in Ambulatory Environments

Date created: 
2016-08-22
Abstract: 

Tracking a high-velocity object through a cluttered environment is daunting for even the human-observer. Vision-based trackers will frequently lose their lock on the object as features on the object become distorted or faded as a result of motion-blurring imparted by the high-velocity of the object. Moreover, the frequent occlusions as the object passes through clutter only serves to compound the issue. To boot, the usual difficulties associated with most vision-based trackers still apply such as: nonuniform illumination, object rotation, object scale changes, etc... Inertial-based trackers provide useful complementary data to aid the vision-based systems. The higher sampling rates of the inertial measurements gives invaluable information to be able to track high-speed objects. With the IMU attached to the object, the inertial measurements are immune to occlusions unlike their visual counterparts. Efficient combination of visual as well as inertial sensors into a unified framework is coined visual-inertial sensor fusion. Visual-inertial sensor fusion is a powerful tool for many industries: it allows the medical practitioners to better understand and diagnose illnesses; it allows the engineer to design more flexible and immersive virtual reality environments; and it allows the film-director to fully capture motion in a scene. The complementary nature of visual and inertial sensors is well-toted throughout these industries, the faster sampling rate of the inertial sensors fits lock-and-key with the higher accuracy of the visual sensor to unlock the potential for algorithms capable of tracking high-velocity objects through cluttered environments. Inevitably, sensor fusion is accompanied by higher algorithmic complexity and requires careful understanding of the components involved. For this reason, the approach taken in this thesis is a ground-up approach towards a complete visual-inertial system: from camera calibration all the way to handling of asynchronous sensor measurements for sensor-fusion.

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

Transmission of JPEG2000 Images over Cognitive Radio Networks

Author: 
Date created: 
2016-08-12
Abstract: 

Cognitive Radio (CR) is an efficient way of spectrum utilization, because secondary users (SUs) with bandwidth-demanding applications such as multimedia can get access to licensed frequency resources opportunistically and resolve their bandwidth limitations. Among all multimedia formats, JPEG2000 is a suitable candidate for cognitive radio networks thanks to its unique features. In conventional resource allocations for CR systems, all data bits are assumed equally important. However, different parts of the JPEG2000 bit stream have different contributions to the quality of the received image. Therefore, in this thesis, an unequal power allocation method is used to allocate the available power to the coded bits based on their importance in the image quality. Furthermore, bits with higher significance are further protected by using sub-channels with better channel quality. Thus, the likelihood of significant bits being received correctly is increased. The optimal solution is obtained by minimizing the image distortion without violating the interference requirement of the primary users (PU). The performance of the proposed method is demonstrated by simulation results.

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

A Context-Aware Model for Dynamic Adaptability of Software for Embedded Systems

Date created: 
2016-08-08
Abstract: 

The scientific contributions of this thesis are three-fold. Firstly, a novel specialized embedded systems software architecture for contextawareness is presented. This architecture is developed for use on a resource constrained hardware platform and is low latency. For firmware applications with many sources of context, a specialized architecture is important to achieve code readability, modularity, extensibility and maintainability. Context in embedded systems firmware development is defined as changeable and characterizing information such as sensor data (IR - infrared, GPS, accelerometer) or profile attributes (user, vehicle, device, etc.). A second focus was on dynamic architecture adaptability in the form of a cognitive engine which processes real-time updates to its user-configurable module. Dynamic adaptability improves the application software's flexibility and responsiveness according to different user requirements or varying operational conditions. Adaptability is defined as system changes according to changes in context and in terms of the four W's - why are there changes, what remains unchanged, when do the changes occur and who manages these changes. Thirdly, the concept of context-aware map logic (CAML) is introduced. Cognitive engine updates are performed using these logic maps which are derived from/inspired by fuzzy cognitive maps (FCM) and GPS (global positioning system) coverage maps. The logic maps feature phi, delta, timer, complement, latched and momentary operands. The logic maps were specifically designed for resource constrained hardware. No previous work has been done on the use of fuzzy cognitive maps specifically with linguistic weights for enabling dynamic, resource constrained firmware adaptability. Fuzzy cognitive maps are at the intersection of fuzzy logic and neural networks. A resource constrained hardware platform is defined as a single-processor microcontroller with low processing power and limited memory space as compared against large memory, multi-core, multi-media processors e.g. cell-phones. The targeted hardware platform could be a legacy processor or a low power processor typically found in wireless sensor networks or energy-aware or cost-aware solutions. Context-awareness is an important topic in the wireless sensor networks research field. Wireless sensor networks comprise wirelessly enabled embedded systems for data acquisition and control for a wide array of applications. In this thesis context is defined as changeable and characterizing information such as sensor data, profile attributes or explicitly provided user information. The embedded systems software architecture is a layered model with context and cognitive planes which focus on dynamic adaptability. The context plane features a microarchitecture, which includes context collectors, context controllers and a context task based coordinator. The cognitive plane is responsible for dynamic adaptable logic reconfiguration inspired by fuzzy cognitive maps. Proof-of-concept firmware was developed for a wireless physiological sensor showing context collector implementation. An ATE (automatic test equipment) test architecture was also developed for the sensor highlighting architecture development and providing the groundwork for the context controller development. The lead-up to the cognitive engine is explored in an introduction to fuzzy cognitive maps, its implementations and applications to current research. An industrial application, Novax's Accessible Pedestrian System (APS) and simulations using the Rapita suite of tools are presented.

Document type: 
Thesis
File(s): 
Supervisor(s): 
Bozena Kaminska
Department: 
Applied Sciences: School of Engineering Science
Thesis type: 
(Thesis) Ph.D.

Enhanced Digital Imager Defect Analysis with Smaller Pixel Sizes

Date created: 
2016-08-03
Abstract: 

Digital imager pixels are shrinking resulting in an increased rate of pixel defects. These defects are known as “Hot Pixels” that are permanent in nature and develop in-field. The number of hot pixels in a given digital imager increases over time. This research experimentally measures defect rates for pixels from 7 μm to those in the cellphone camera range, as low as 1μm. New software algorithms and techniques have been developed to compensate for increasing noise levels in the 2 to 1 μm range. This has allowed the creation of an empirical model that provides accurate projections of defect rates as pixel size decreases and sensitivity increases. Results show that the hot pixel rate increases by 8.9 times as pixels shrink by a factor of 2. Additionally, digital imagers allow us to explore soft errors (known as single event upsets) in a way that can’t be done in traditional ICs.

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