Theses

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  • Time-Frequency Signal Synthesis and Its Application in Multimedia Watermark Detection
    Time-Frequency Signal Synthesis and Its Application in Multimedia Watermark Detection
    A novel approach is proposed in this thesis to synthesize the time domain chirp signal from the joint time-frequency distribution (TFD). The objective is to reconstruct the original signal from its corrupted version. The new signal synthesis technique is based on the Discrete Polynomial Phase Transform (DPPT) and the TFD of the signal to be synthesized. The TFD is used to separate the mono-component signals from a multi-component signal. The DPPT is then applied on the estimated mono-components to have a final synthesized version of the individual time domain signals. The candidate TFD to be used in the synthesis technique is chosen from a group of common TFDs based on their performance with different types of signals. The criteria for the comparison are joint time-frequency localization, low susceptibility to noise, cross-term suppression and the precision of the instantaneous frequency estimated from these distributions. Smoothed Psuedo Wigner-Ville Distribution is chosen as the processing TDFD in the proposed signal synthesis technique. The proposed chirp synthesis technique is applied to detect the presence of the chirp signal embedded as a watermark message in multimedia security applications. The technique can detect the presence of chirp signals from a corrupted chirp with a bit error rate up to signal synthesis is proved to be less than that of the detection method based on the Hough Radon Transform and the proposed signal synthesis technique may also be used as an error correction tool in other applications.
    Time-Varying Coefficient Models And The Kalman Filter : Applications To Hedge Funds
    Time-Varying Coefficient Models And The Kalman Filter : Applications To Hedge Funds
    There are various studies concerned with the estimation of stochastically varying coefficients for the hedge fund series but just [sic] few are available in the literature that study the model with time-varying coefficients and non-linear factor, or make a comparison of the series before and during the financial crisis. This work studies a model with linear and non-linear factors with stochastically varying coefficients to obtain better estimation of the exposure of the hedge fund and accuracy in the results. Better exposure estimates implies better hedging against negative changes in the market hence a reduction in the risk taken by the hedge fund manager. Besides, different techniques have been studied, implemented and applied in this thesis to estimate and analyze time varying exposures of different HFRX Index (an index that describes the hedge fund industry performance).The study shows that option-like models with time-varying coefficients perform the best for most of the HFRX indexes analyzed. It also shows that the Kalman Filter technique combined with the Maximum Likelihood Estimator is the best approach to estimate time-varying coefficients. In addition, we provide evidence that Kalman Filter is in a better position to capture changes in the exposure to the market conditions.
    Time-frequency analysis of spread spectrum based communication and audio watermarking systems
    Time-frequency analysis of spread spectrum based communication and audio watermarking systems
    In this study, we present novel applications of time-frequency analysis to spread spectrum based communication and audio watermarking systems. Our objective is to detect and estimate non-stationary signals, such as chirps, that are characterized by directional elements in the time-frequency plane. Towards this goal, we model non-stationary signals using the matching pursuit decomposition algorithm, generate a positive time-frequency representation of the signal model using the Wigner-Ville distribution and estimate the energy varying directional elements using a line detection algorithm based on the Hough-Radon transform.Spread spectrum communication systems frequently encounter nonstationary signalswith energy varying directional elements as hostile jamming signals. In this thesis, we develop a new interference excision algorithm for spread spectrum communication systems based on the directional element estimation algorithm. At the receiver, we first excise the interference from the spread spectrum signal before despreadingand data symbol detection. The new algorithm can excise single and multicomponent interferences such that the spread spectrum system can reliably detect the transmitted message symbols even, when the interference power exceeds the jammingmargin of the system. We verify the effectiveness of the interference excision algorithm using simulation studies.Watermarking is the process of embedding imperceptible data into the host signal for marking the copyright ownership. The embedded data should be extractable to prove ownership. Watermarking systems face problems similar to those in spreadspectrum communication systems, namely, intentional attacks by the adversaries. Inwatermarking, the adversaries try to obliterate the embedded watermark in order toprevent its detection by authorized parties. In this thesis, we develop a spread spectrum audio watermarking scheme, where we embed perceptually shaped linear chirps as watermark messages. The directional elements of the chirp signals represent different watermark messages. We extract the watermark by first detecting the transmittedmessage symbols in the spread spectrum signal. We then use the directional elementestimation algorithm based on the time-frequency analysis as a post-processing tool to minimize the effects of hostile attacks on the extractability of the embedded watermark. We demonstrate the robustness of the algorithm by extracting the watermarkcorrectly after common signal processing operations representing hostile attacks byadversaries.
    Time-mode signal processing and application in ΔΣ ADC design
    Time-mode signal processing and application in ΔΣ ADC design
    An all-digitally implemented 1st order and a 2nd order time-mode ΔΣ ADCs are proposed and presented in this dissertation. Each proposed ΔΣ ADC consists of a voltage-to- time integration converter, a seven-stage gated ring oscillator functioning as a 3-bit quantizer, and a 7-stage digital differentiator that provides noise-shaping and frequency feedback. The 2nd order architecture differs from the 1st order by cascading two digital differentiators. The 2nd order design improves noise-shaping characteristic and SNDR. However it does not effectively suppress the harmonic tones due to the non-linear effect of the circuit components. Thus a detailed analysis of the nonlinear characteristics of the modulator is conducted. Designed in IBM 130 nm 1.2 V CMOS technology and with a 100 kHz 100 mV input, the 1st order time-mode ΔΣ ADC exhibits an SNDR of 45.5 dB over 0.4 MHz bandwidth with power dissipation of 1.1mW. In comparison, the 2nd order ADC provides 54.8 dB SNDR, which equivalently offers an ENOB of 8.8 and it consumes 1.45 mW RMS power. The figure- of-merit of the 2nd order time-mode ΔΣ ADC is 407 pJ/step. Since the order of the system cannot be increased by simply cascading more differentiator stages, a time-mode ΔΣ ADC architecture employing a time-mode loop filter is suggested in the last chapter. Several key building blocks including a time amplifier, time register and time adder for implementing such a loop filter are presented. The time amplifier has an input dynamic range of 50ps and provides a gain of 20. The implemented time register has a dynamic range of 5ns and a peak error of 2% over the 5ns full scale. The time adder remains high accuracy as long as the input time difference is no greater than 1:6ns.
    Tissue characterization of prostate cancer using quantitative analysis of low frequency ultrasound
    Tissue characterization of prostate cancer using quantitative analysis of low frequency ultrasound
    Current accepted methodologies used for detection of the prostate rumor involve measurements of prostate specific antigen (PSA) levels, patient age followed by ultrasound guided biopsies leaving a lot to desire in the ability to correctly identify lesions. Also PSA level test has been shown to produce a high number of false positives leading to unnecessary invasive biopsies. The goal of this thesis is to investigate the use of trans-rectal conventional low frequency (1-10MHz) ultrasound as a non-invasive imaging modality for the detection of prostate tumors. Currently we are investigating the use of multiparameter spectroscopic analysis of the ultrasound radio frequency signal in combination with ultrasound elastrographic imaging of the prostate and correlating the results with whole-mount histopathology from radical prostatectomy. Ten patients with prostate cancer prior to surgery were subjected to trans-rectal conventional low frequency ultrasound scans. Parametric maps are generated for each individual spectral parameter. Ratios of disease area versus normal prostatic tissue are identified using low frequency ultrasound and compared with the equivalent ratios obtained from whole-mount histopathology. Preliminary results show that areas of suspected disease identified by spectral parameters correlate with areas of disease presence in the corresponding whole-mount sections. An initial software platform performing visualization of areas of disease based on parametric maps generated from spectral analysis methods was developed.
    Tool accessibility with path and motion planning for robotic drilling and riveting
    Tool accessibility with path and motion planning for robotic drilling and riveting
    Robotic applications in aerospace manufacturing and aircraft assembly today are limited. This is because most of the aircraft parts are relatively small or have complex shapes that make tasks like robotic drilling and riveting more challenging. These challenges include tool accessibility, path planning, and motion planning. In this thesis, a process methodology was developed to overcome the tool accessibility challenges facing robotic drilling and riveting for aircraft parts. The tool accessibility was analyzed based on the Global Accessibility Area and the Global Accessibility Volume to determine the accessible boundaries for parts with zero, one and two surfaces curvatures. The path planning was optimized based on the shortest distance, least number of steps, and minimal tool orientation change. The motion planning was optimized based on the s-curve using the robot’s maximum velocity and acceleration for minimum cycle time and maximum production rate. A software application was developed to simulate the tasks.
    Top Marks for Quality Parks
    Top Marks for Quality Parks
    As the City of Toronto and the Greater Golden Horseshoe continue to become more densely populated resulting from the Provincial Growth Plan, increased stresses on existing parks spaces will occur due to overuse. The focus of this research is to evaluate Toronto’s effectiveness in maintaining quality park spaces according to the Park’s Plan (2013-2017) in the City through the trial of a Park Report Card that focuses on basic amenities in parks in the densest wards. The methodology was adapted from New York City’s Park Report Card which involved the definition of basic amenities and a scoring scale for their functionality. The observed parks did not meet quality park standards according to the Parks Plan and a series of recommendations to improve the level of quality were provided.
    Toronto the Good? The Access T.O. Policy - Making Toronto a Sanctuary City
    Toronto the Good? The Access T.O. Policy - Making Toronto a Sanctuary City
    This paper examines Toronto's Access T.O. policy, a policy created to transform Toronto into a sanctuary city. I argue that the Access T.O. policy has made progress towards turning Toronto into a practicable sanctuary city. However, I also highlight areas where the policy needs improvement and further expansion. I also show how the City of Toronto's Access T.O. policy offers an alternative approach to migration and settlement policies found at the level of the Canadian federal state and illustrate how these policies diverge and contradict. The Access T.O. policy, like other sanctuary cities, is shown to provide an alternative understanding and implementation of citizenship, belonging, rights, ethics and morality, human agency, security and borders to that found in federal state policies. The paper provides background information on sanctuary cities prior to entering this aforementioned discussion and concludes with considerations for Access T.O.'s continued expansion and implementation.
    Toronto’s apartment tower renewal initiative: infusing value into surplus lands for community development
    Toronto’s apartment tower renewal initiative: infusing value into surplus lands for community development
    Toronto is home to over 1,189 apartment towers built between 1945 and 1984, following LeCorbusier’s “tower in the park” model. Today, many apartment towers communities are fraught with issues that demand immediate and focused attention. Several towers are now approaching 50 years of age, and are beginning to show signs of decay, neglect, and decline, presenting concerns surrounding their physical condition, environmental impacts, and access to essential amenities within close proximity. The former Mayor of Toronto David Miller responded by initiating a study to identify solutions to growing concerns, and financing strategies to achieve it. Notwithstanding these issues, tower neighbourhoods have access to an exorbitant amounts of surplus lands that could accommodate infill activities, and spur investments in these neighbourhoods. The goal of this paper is to assess if surplus lands can be leveraged as the primary funding source to finance the goals and objectives of Toronto’s tower renewal initiative.
    Toronto’s new social housing waiting list: putting the choice-based rental model into local context
    Toronto’s new social housing waiting list: putting the choice-based rental model into local context
    Choice-based rental models are under consideration in Ontario for their ability to provide more clientcentric service while increasing efficiency and cost-effectiveness for housing providers. They are compelling because of their potential for empowerment and provision of housing choice, though it remains unclear how exactly it achieves these outcomes. This paper asks how a choice-based rental model can help achieve improvements to affordable housing policy, reallocate scarce resources, and improve neighborhood planning in Toronto. Implementation issues and successes associated with the model are discussed through a review of literature and a case study of Toronto Community Housing’s ‘My Choice Rental’ pilot program. Recommendations for the model’s use in a growing urban centre like Toronto, Ontario include data collection and preference tracking to inform housing policy updates, using technology to improve the user experience, and conducting and participating in research to determine whether the model is performing as intended.
    Toward A New Tectonic
    Toward A New Tectonic
    Architecture’s role as the mediator between the environment and occupant has been discarded, handing off the roles of structure and environment to engineering, and leaving itself spatial planning and aesthetics. Simultaneously, standardization has further reduced the expressiveness of architecture. The tectonic traditions of architecture have been cast aside in favour of a pan-global style, and remain marginalized with the current trend toward the overly formalist design of the first digital era. In opposition to the generic, thin architecture that has been produced through the use of climate control - digital simulation of environmental forces, materials, and construction, can allow for the generation of a thick architecture of specificity, tuned and expressive of its place through an expanded sense of the tectonic material basis of form. This associative architecture, formed by physical forces, with a basis of ‘necessity’ will allow for an attempt to reassert a more substantial architecture through digital means.
    Toward a corporal architecture building about the body
    Toward a corporal architecture building about the body
    Throughout history the human body has formed the subject, defined the scale and proportion, and inspired the tectonic and symbolic language of architecture. While modern methods sought to codify the body for the purposes of standardized measurement, ergonomics, and the development of building codes, the implications derived from this approach have resulted in limited and standardized procedures for designing space in relation to the body. Recent advances in materials science, portable computing, and sensing technologies have opened up several possibilities for a deeper level of engagement and interaction between the body and its environment. As wireless communications continue to blur the boundaries between personal and global space, new dialogues are emerging that implicate both intimate material interfaces and wider organizational frameworks. Introducing the notion of ‘wearable space’, parallels between fashion and architecture are drawn as a means of re-examining the relationship between the body, clothing and architecture; the first, second and third skin of the body respectively.