title: Compressed Sensing of Block Sparse Signals with Application to Wideband Spectrum Sensing

abstract:
In many applications of compressed sensing, the signal is block sparse. Here, we propose a family of iterative algorithms for the recovery of block sparse signals, referred to as iterative reweighted $\ell_2/\ell_1$ minimization algorithms (IR-$\ell_2/\ell_1$).
As an example, we apply the proposed algorithms to wideband spectrum sensing (WSS). Our simulation and analytical results on the recovery of both ideally and approximately block sparse signals show that the proposed iterative algorithms have significant advantages in terms of accuracy and the number of required measurements over the existing methods.
We also propose a of reweighting scheme for the recovery block sparse signals with known borders to improve the performance of the so-called approximate message passing (AMP) algorithm.
For the case of unknown borders, we propose an iterative algorithm which combines a border detection scheme with a recovery algorithm for block sparse signals with known borders. Simulation results, both in noiseless and noisy scenarios, show a considerably better performance/complexity trade-off compared to other state-of-the-art recovery algorithms.
WSS is a significant challenge in cognitive radios (CRs) due to requiring very high-speed analog-to-digital converters (ADCs), operating at or above the Nyquist rate. Here, we first propose a very low-complexity zero-block detection scheme that can detect a large fraction of spectrum holes from the sub-Nyquist samples, even when the undersampling ratio is very small.
We then propose an iterative low-complexity scheme for the reliable detection of zero blocks in a block sparse signal.
This scheme is based on the application of verification based (VB) recovery algorithms in compressed sensing to block sparse signals. To apply both schemes to WSS, we devise a block sparse sensing matrix by designing a novel analog-to-information converter (AIC). The AIC, the sensing matrix and the VB algorithms can be optimized such that the largest number of zero blocks for a given number of measurements can be detected. These works introduce a paradigm in the recovery of block sparse signals, where one is interested in partial detection of the complement of the support set, reliably, rather than the full recovery of the signal or its support.


title: Ice island variability in polarimetric Synthetic Aperture Radar:  An exploratory analysis to improve detection and ice classification

abstract: Synthetic Aperture Radar (SAR) satellite imagery is often used to discriminate ice types and identify glacial ice hazards to marine operations. This 'data-mining' study examined 123 polarimetric SAR variables in 70 RADARSAT-2 images to assess their utility in separating ice islands (large tabular icebergs) from other ocean covers. Difference of means tests identified five SAR variables to separate each ocean cover. Further SAR variables were found using forward-selection in Redundancy Analysis (RDA). RDA also identified incidence angle, air temperature and wind speed as primary confounding factors for all assessed ocean covers. Support Vector Machine classification using five SAR variables was used to develop an ocean cover classification model. This technique competently distinguished open water, first- and multi-year ice, but could not discriminate ice islands. The selected SAR variables, many not previously investigated, warrant further study and the RDA approach showed promise to guide future development of remote sensing classifiers.


title: PGP Auth: Using Public Key Encryption for Authentication on the Web

abstract:
The majority of authentication systems use text passwords, as they provide a flexible method of authenticating on a wide variety of devices. Unfortunately, having suffi- ciently strong passwords does not protect users against phishing or offline guessing attacks. In this thesis, we present a new authentication mechanism that uses PGP.
We iteratively designed PGP Auth, implemented it, and conducted user testing. Users rated the software highly and indicated that they would be very likely to use the software. They also liked the idea of having a single password to access their accounts and appreciated the security of using PGP as an authentication system.
We believe that with a refined user interface, PGP Auth is a viable authentication mechanism that addresses many of the security vulnerabilities of traditional text password authentication. We also provide recommendations to aid in the development of future versions of PGP Auth based on our results.


title: Enhancing Rates In Relay Channels

abstract:
The main objective of this study is to investigate the structures and procedures which are promising to achieve higher rates and larger rate regions in the relay channels and the communication networks that contain relay nodes. In particular, the study places particular emphasis on the relaying techniques pertaining to compress-and-forward.
The thesis first examines a generalization of decode-and-forward (DF) and compress-and-forward (CF) in Gaussian channels. Although this generalization has been known for over thirty years, the result in this thesis is the first to illustrate the signal-to-noise ratio (SNR) regions in which the generalization reduces to constituent DF or CF schemes. In particular, the thesis demonstrates the existence of SNR regions in which the generalization is guaranteed to supersede both DF and CF, but with a gain of within 0.5 bits per channel use.
Having gained insight into the random binning in the CF scheme, this thesis argues that a new decoding procedure exploiting the N-to-1 mapping based on binning is able to relax the rate constraint on the relay transmission, and generalize the noisy network coding based schemes which are constrained to the 1-to-1 mapping. This thesis identifies two instances in which exploiting the N-to-1 mapping inherent in this generalization yields rate gains, even though it does not yield such a gain in other multimessage networks.
In the analysis of a secure communication problem, the thesis introduces the concept of “friendly” eavesdropper in a broadcast channel in the presence of a malicious Gaussian jammer. Taking advantage of the N-to-1 mapping, it is shown that the new decoding procedure enables CF to achieve the capacity of the channel.


title: Medicating the Crisis: Investigating the Links Between Precarious Employment, Mental Health Issues, and the Reliance on Antidepressants as Treatment

abstract: My research engages in literature that discusses the relationship between precarious employment conditions, declines in mental health, and the way mental health issues are treated with pharmaceutical technologies – namely antidepressant medication. In this dissertation, I aim to contribute to this discussion by a) situating the relationship between precarious labour conditions and mental health within a specifically capitalist society, and b) investigating the pharmaceutical treatment of individual illness experiences and mental health issues that can be linked back to broader social structures. In doing so I provide an analysis of the process of medicalization, which locates mental health aetiology as primarily biochemical and focuses on medical, commodity-based interventions, specifically antidepressants, in response to illness experiences – where dis-ease becomes disease. My primary method is a theoretical analysis of capitalist commodity production, the social process of medical knowledge production, medicalization, and development of pharmaceutical technologies. The goal of my theoretical analysis is to achieve new insight regarding my research questions by bringing together existing bodies of literature. A narrative analysis of stories gathered through in-depth interviews and autoethnographic accounts complement the main theoretical analysis, and are used to explore personal experiences of precarious social conditions related to mental health and work. I pay particular attention to systems of oppression enabled and fed through capitalism, such as gender, ability, and class relations. I argue that a reliance on antidepressant medication in response to the distress of working people and the unemployed poor plays an important role in enabling the continuation of dysfunctional social conditions. I argue that classifying mental health issues as purely medical erases social structural factors in the development of illness, and removes the serious consideration of such factors from diagnosis and treatment. This erasure also limits people’s capacity to act on pertinent questions they may have regarding their own emotional fulfillment and social wellbeing. Such disempowerment frustrates the radical imagination and pursuit of more sustainable and equitable ways of developing and maintaining genuine health.


title: Reclaiming the End(s) of Politics: Considerations on the Possibility of a Renewed Agonistic Understanding of the Post-Political

abstract: This thesis seeks to combine two concepts that are generally considered to be antithetical: agonistic democracy and the post-political. The starting place for the thesis is Chantal Mouffe`s understanding of the political, an account that links the construction of political identities, politics and radical democracy. Suggesting that Mouffe`s treatment offers a fertile ground for thinking about the future of democracy, this thesis develops a political approach where the post-political is placed at the forefront of democratic efforts, with the hope that it will counteract the interconnected problems of the securitization of politics and the devaluation of pluralism that plagues Mouffe`s political thought. Unearthing the conceptual connections between Alexandre Kojeve`s understanding of political subject formation and Mouffe`s empty signifier, this thesis investigates the possibility of articulating an understanding of the concept of the post-political that does not result in a totalitarian utopia as the Mouffean critique of the concept suggests.


title: An Assessment of Wheelchair Provision in the Majority World With a Focus on Uganda through Fieldwork

abstract: This research provides an assessment of wheelchair provision for people with disabilities in the majority world. The research was conducted through a series of questionnaires, interviews, and observations with multiple stakeholders to gain different perspectives on the same topic. It discusses the limitations of national small-scale wheelchair provision, the limitations of international large-scale wheelchair provision, and the state of wheelchair service-delivery in the majority world. The research with international large-scale wheelchair producers was conducted in Canada, while the research with the remaining stakeholders was done during fieldwork over a ten day period in Uganda. The results of the research provide several insights into wheelchair provision, including limitations to standardization, resources, business training, micro-logistics and reverse-logistics. While wheelchair service-delivery is present in Uganda, it is not regulated or consistent among national small-scale wheelchair producers and international large-scale wheelchair producers.


title: The effect of paternal dietary folic acid on male fertility and embryo development in Balb/c mice

abstract: In 1998, Canada fortified white flour with folic acid targeting women of childbearing age to reduce the incidence of neural tube defects. Resultantly, FA intake in men increased. This study investigated the effect of paternal FA intake on male fertility, embryo development, and methylation dependent gene expression in unexposed descendants of Balb/c mice. Folate deficiency resulted in a higher number of embryos with congenital anomalies and developmental delay, and a lower prevalence of ossification in bones of the skull. Placenta size was higher with higher FA intake. BiSulfite Amplicon Sequencing was used to characterize methylation changes in heritable epigenetically regulated genes for which hepatic expression was dependent on grand-paternal FA exposure during early development or post-weaning. CpG islands in promoters of three genes had subtle diet-induced methylation changes. This study highlights the importance of adequate paternal FA intake, emphasizing that fortification can directly impact embryo development and affect future generations.


title: ACH Walkthrough: Designing and Building a Web Application for Collaborative Sensemaking

abstract: This thesis describes the research and development of a prototype for a co-located collaborative intelligence analysis tool: ACH Walkthrough. The tool is a collaborative variation of an established structured analysis method called Analysis of Competing Hypotheses, originally developed for intelligence analysis. Recent changes to web application architectures offer important opportunities to produce visually rich applications that support co-located and remote collaborative decision making scenarios. We begin by reviewing the literature on sensemaking and development frameworks for surface applications. We explore architectural issues in using web frameworks for collaborative applications. We then present the design and implementation of ACH Walkthrough, our prototype design for team-based intelligence analysis, and the evaluation of the application's major architectural components. Finally, we document feedback on the tool and explore alternative designs and architectural approaches.


title: Evaluating the Effectiveness of Three Dimensional Geovisualization Tools in Communicating Climate Change Impacts, A PEI Case Study

abstract: Three-dimensional geographic visualization (3D geovisualization) tools have been praised as a solution to the challenge of communicating climate change impacts by capturing public interest, making the issues more personal, and motivating users to take action. However, evaluation methods are not standardized, especially with novice and expert users. Using a combination of workshop surveying and usability testing, I addressed this issue by studying the Coastal Impact Visualization Environment (CLIVE) tool, which allows users to visualize potential sea-level rise and coastal erosion scenarios on PEI (Prince Edward Island). I found that geovisualization tools have the capability to educate and engage users about potential climate change impacts, but generally fade from the users’ memories over time, leading to a lack of overall motivation to take climate change action. This has paved the way for the development of a pilot cybercartographic atlas to keep the discussion about climate change impacts accessible.


title: Interaction History Support for Web Applications

abstract:
All users of complex software make decisions that they may later wish to change. Many computer systems have tools to support this need for revision, such as the undo command. However, the common history tools (like undo) do not support exploratory, epistemic interaction well. And there are common, non-specialized tasks that are difficult in common computer systems, but would be much easier with improved support for managing interaction history. Desktop computing environments have well-established norms for how undo works, but there is room to explore this in newer computing environments, such as the Web and surface computing, as their design culture has not stabilized to the same extent. We argue that history tracking needs to be more accessible to users.
We developed a prototype JavaScript library for Web applications that lets users keep a history of all their interaction states, including those that would be discarded by using a traditional stack-model undo system. The history is presented to users in a tree structure similar to the model used in source control software. We ran a usability study of our system with two applications designed to encourage the kind of exploratory behaviour we wanted to support. We identified usability improvements that could be made, but the study suggests that this kind of system could be generally useful even in non-specialized fields.


title: Walk This Way: A Kinematic Point-Light Investigation of Victim Vulnerability

abstract: Research suggests that certain individuals exhibit vulnerability through their gait, and that observers select such individuals as those most vulnerable to victimization. It is currently assumed that the vulnerable gait pattern is an expression of one’s submissiveness. Study 1 utilized kinematic point-light display to record individuals walking. The findings suggested that victimization history was related to gait vulnerability. The results also indicated that, contrary to expectation, individuals with more vulnerable features in their gait were more likely to self-report dominant personality characteristics, rather than submissive characteristics. In Study 2, a sample of observers watched the point-light recordings and rated the walkers on their vulnerability to victimization. The results suggested that observers agreed on which walkers were easy targets; they were also accurate in that the walkers that they rated as most likely to experience victimization tended to exhibit vulnerable gait cues. Implications of the findings are discussed.


title: Reference and Grammar: Reasserting Wittgenstein's Picture

abstract: The aim of this essay is to present a novel line of argument in support of Ludwig Wittgenstein’s view of philosophy of language. It consists in three parts. First, it explores a family of referential theories of meaning belonging to the tradition of Millian semantics – a family dubbed ‘Millian externalism.’ Second, it draws on the work of both Wittgenstein and Noam Chomsky to undermine the tenability of Millian externalism, all the while generating insights into the nature of an adequate semantic theory as it proceeds. And third, from the fact that Millian externalism fails insofar as it purports to be a scientific theory of meaning, the essay concludes that philosophy of language must give in to a theory of meaning which endorses Wittgensteinian quietism. If it refuses, then it must conform to the methodology of linguistics.


title: Relationship, Particularism, and a Case Study of Africville: an Argument for Relational Principles

abstract: In this work, I argue that moral discourse should make use of relational moral principles. To do this, I examine feminist works in both care and relational theory that reject traditional western conceptions of the self and of principles. Through an examination of Jonathan Dancy’s particularism, I argue that a complete rejection of principle is not a viable option for feminists. Instead, contextually sensitive principles that have their grounding in the importance of relationship in human life can and should be formulated. I present examples of principles that operate in this way, and show their utility through applying them to the case study of the relocation of the community of Africville that was once on the edge of Halifax.


title: Tracking Evolutions in CMHC Policy (1965-2006) Using Bob Jessop's Strategic Relational State Theory

abstract: Sociologist Bob Jessop theorizes that the actions of the capitalist state involve it weighting competing class interests, some of which are invariably afforded greater relevance depending on given political economic circumstances. The favourable selection of certain class interests at the expense of others is a process, moreover, that is subject to influence by changing historical blocs. This thesis examines how the state, using the CMHC as its conduit, has over time managed the often conflicting class interests associated with affordable housing policies. My central argument is that Canada’s shift between the golden and globalization historical blocs saw housing policy shift away from Keynesian principles towards globalization, neoliberalism, and financialization. Whereas the golden era saw the state institute numerous publicly funded measures in an effort to solve housing issues, the globalization era compelled the state to withdraw its presence in housing, and more explicitly favour investors and the private sector generally.


title: Use of Entrepreneurial Marketing in Fostering Resellers’ Adoption of Smart Micro-Grid Technology

abstract: This thesis investigates how entrepreneurial marketing (EM) can foster suppliers' adoption of smart micro-grid (SMG) technology. Previous studies have emphasized the technical aspects of this new area of power systems industry. However, there is a need to understand the market adoption, especially that of resellers who act as intermediaries between suppliers and end-customers. An online survey based on the technology acceptance model (TAM) and EM literature was used to gather data from 99 resellers. The data were analyzed using the partial least squares method to validate a model of the relationships between resellers’ antecedents and intention to adopt SMG technology, and the role of suppliers' EM for the adoption. The results suggest that TAM can only partially be applied to the reseller context. Moreover, suppliers need to demonstrate EM, particularly entrepreneurial orientation, to increase resellers’ performance expectancy and to decrease effort expectancy to foster the diffusion of novel SMG technology.


title: Acoustic Imaging Using a 64-Node Microphone Array and Beamformer System

abstract: Acoustic imaging is difficult to achieve in noisy and reverberant environments. Microphone arrays offer an effective approach to obtaining a clean recording of desired acoustic signals in these environments. In this thesis, we have designed, implemented, and evaluated a 64-node microphone array system for acoustic imaging. We have applied a delay-and-sum beamforming algorithm for sound source amplification in a noisy environment, and have explored the uses of the array and beamformer by generating the sound intensity map to reconstruct the acoustic scene. Our experimental results show a mean error of 1.1 degrees for sound source localization, and a mean error of 13.1 degrees for source separation. In addition, we also used the system to image seven different materials with audible sound, and obtained their reconstructed acoustic maps as well as frequency response curves, from which we are able to detect the differences between textures based on their acoustic response powers.


title: Electrical Impedance Tomography in 3D: Characterization and Evaluation

abstract: Electrical Impedance Tomography (EIT) uses body surface electrical stimulation and measurements to create images of the conductivity of contrasting fluids. 3D EIT has a strong potential to image regional inhomogeneities in the lungs. This thesis seeks to characterize 3D measurement patterns, capture regional inhomogeneities in the lungs caused by gravitational effects due to change in posture, and to test the ability of 3D EIT to measure change in global lung volume. Results indicate that 3D EIT can provide meaningful measurement of lung volume change. Functional EIT image analysis shows that different postures will cause changes in regional lung behaviour from the standing postures to a declined posture. However, results are inconsistent. Planar and Zigzag Offset patterns are shown to successfully capture regional inhomogeneities in lung mechanics using certain inhalation features. Overall, this thesis presents analysis methodologies (simulation, phantom, and experimental) to characterize and optimize 3D EIT imaging.


title: Differences in methane production, storage and transport among plant community types during a wet summer at Mer Bleue bog, Ottawa

abstract: This study assessed indicators of methane (CH4) production, storage and transport among plant community types to investigate the spatial and temporal variability in CH4 dynamics during a wet summer at the Mer Bleue bog. Community type was largely differentiated by sedge (Eriophorum vaginatum) presence, which increased as the average water table depth approached the surface. Stable isotope analysis identified CO2 reduction as the dominant methanogenic pathway in all plots, but with more depleted source signatures as percent Eriophorum increased, possibly due to CH4 transport via aerenchymatous tissues. Increasing peat temperature contributed to increasing CH4 concentrations at 50 cm, near the long-term average water table, and dissolved organic carbon and total dissolved nitrogen at all depths, and a seasonal increase in chamber CH4 emissions. Plant community did not relate to spatial differences in pore water characteristics, but increasing percent Eriophorum was associated with greater CH4 emissions.


title: Structural Development of Hippocampal CA3 Pyramidal Neurons and Relation to the Development of Spatial Learning and Memory in Rats

abstract: The dentate gyrus-CA3 circuit in the hippocampus is highly plastic during development and morphologically responsive to various environmental outputs. The current study investigated the structural changes in CA3 pyramidal neurons during development (p18-p24) and the effect of AMPA receptor antagonism on spatial learning and memory. Exp.1 showed individual changes in the elements of CA3 pyramidal neurons. Some parts expanded with age and others retracted. Golgi analysis revealed a reduction in spine density and an increase in thorny excrescences (TE), suggesting a role for TE in spatial abilities that emerge at the same age. Exp.2 investigated the effect of AMPAr antagonism (NBQX) on spatial function and on CA3 pyramidal neuron structure. NBQX-injected rats showed impaired spatial abilities and individual remodeling in different components of CA3 pyramidal neurons including an increase in spines density and a decrease in TE. This suggest a role for TE in mediating spatial learning and memory.


title: Gendering Temporariness: Stratified Citizenship and Hierarchies of Skill in Canada's Temporary Foreign Worker Program

abstract: The number of workers admitted to Canada through the Temporary Foreign Worker Program (TFWP) has been increasing over time. By 2012, there were almost twice as many temporary residents as permanent residents in Canada (CIC 2013). With the introduction of the Canadian Experience Class, the Conservative government has prioritized the recruitment of high-skilled workers and facilitated their transition to permanence, while limiting the number of low-skill workers and providing them with no such access to permanence. This study considers evidence from parliamentary committees to prove that the government has consistently chosen to maintain the divide between temporary and permanent citizenship despite agreement among witnesses that all temporary migrant workers should have access to citizenship. The study also shows that the TFWP is based on gendered and racist categorizations of skill which places women and racialized workers in predominantly low-skilled categories, making them less able to access formal citizenship and rights.


title: Unsettling Miss Chief and Buffalo Boy: Interrupting Canada's Politics of Reconciliation

abstract: This project explores how the interruptive elements of queer Indigenous art shows reconciliatory processes as founded on desires for a unified national political community. I draw out how these processes centre on a myth of a self-enclosed sovereignty that maintains settler colonial violence. I specifically examine how the artwork of Canadian Two-Spirit artists Adrian Stimson and Kent Monkman is critical of Indigenous-settler relations and in what ways their criticisms speak to current practices of reconciliation. I argue that their artwork are examples of how queer Indigenous art presents alternative images of being that destabilize the conceptualization of sovereignty underpinning Canada’s framework of reconciliation. Such art interrupts by disrupting Canada’s image as a benevolent state and by opening up a space to imagine what political, social, and legal relations might look like with alternative conceptions of sovereignty.


title: Knots That Strain and Threads That Bind: NGO-Grassroots Dynamics in the Movement Web Challenging Canadian Resource Extractivism

abstract: The predominant NGOization thesis typically describes NGO grassroots relationships as disconnected, with the former engaging in hegemonic social formations, the apolitical delivery of services, and shifting accountability structures that alter agendas for social change. By utilizing a hermeneutic phenomenological approach, and in conducting nine in depth interviews with two NGOs and two grassroots groups working within this field, the objective of this thesis is to complicate theories of NGOization by magnifying the threads and knots that comprise the social movement web challenging Canadian resource extractivism. In light of five knots that create tensions and feelings of ambivalence between NGOs and grassroots groups, my findings suggest that they are bound together in this web through five main threads. This thesis asserts that studies on NGOization would benefit from the relational understanding of collective action provided by social movement studies, including the conceptual tools offered through resource mobilization and framing theories.


title: Where States Lie: A Historical Sociological Investigation into the Art of Cover Storying in a Secret Cold War Intelligence Operation

abstract: Secrecy and deception are integral components of ruling, yet remain under-researched and under-theorized sociologically. This thesis draws on two complimentary literatures with the goal of advancing a conceptual framework and agenda for the study of secrecy and deception in government: governmentality studies and dramaturgy. The usefulness of this framework is demonstrated by analyzing the cover storying practices of military officials in Cobra Mist, a secret radar intelligence station built in England in the late 1960s. Based on a theoretical understanding of cover storying, six interrelated themes are developed and substantiated empirically: i) scripting and rehearsing a suitable cover narrative; ii) going public via press release; iii) backstage struggles over cover storying and information leaks; iv) strategies for managing information leakage; v) secret site closure; and vi) the production of mystery. In conclusion this thesis reflects on the methodological limitations of research on government secrecy and offers four possible avenues for future research on cover storying.


title: Searching with Two-Speed Autonomous Mobile Robots

abstract:
We introduce and study various search problems using mobile robots. Specifically we study the problems of exploration and patrolling using a new two-speed model of robots, as well as studying the problems of rendezvous and evacuation using a more traditional one-speed model of robots. The problems are executed on a continuous finite domain by a swarm of n robots. For the two-speed model, each robot r_i has a walking speed w_i and a searching speed s_i, where s_i < w_i. At each moment a robot either moves through the domain with a speed w_i, or it searches the domain with speed s_i.
A search of an interval is completed when each of its points have been searched by at least one of the robots. We want to develop efficient mobility schedules (algorithms) for the robots which complete the search of the interval as quickly as possible. More exactly, we want to maximize the speed of the mobility schedule, defined as the ratio of the interval length compared to the time of completion of the schedule.
For patrolling, a unit interval is to be patrolled collectively by n two-speed robots. A robot patrols a portion of the domain by searching it. Each robot is allowed to patrol only in one of the two directions. We want to schedule the perpetual movements of the robots to minimize the idle time, defined as the maximal time interval any point is not visited by some patrolling robot.
We also study randomized rendezvous on a circle: Two one-speed robots begin at different locations on a circle and want to minimize the time required to find each other. The robots have different speeds, are unaware of their own speed, are equipped with identical chronometers, and each have access to one or more random bits.
Finally, we study the evacuation problem: Distributed on a unit circle are k exits; two identical one-speed robots are placed on the circle. The goal of the evacuation problem is to give an algorithm for the robots which minimizes the time required for both robots to reach an exit.


title: Conservation genetics and habitat characteristics of Few-flowered Club-rush (Trichophorum planifolium (Spreng.) Palla), an endangered woodland sedge in Canada

abstract: Trichophorum planifolium, like many Canadian species-at-risk, reaches the northern extent of its range in Canada, but is common farther south in the United States. Peripheral populations may be important sources of adaptive and evolutionary potential, possessing unique genetic diversity and/or adaptations to local conditions. However, such populations are typically small and isolated and may therefore be susceptible to extinction. Using microsatellite markers, we compared the level and spatial distribution of genetic diversity and environmental characteristics between the Canadian and American populations of T. planifolium. Overall, low diversity and high inbreeding were detected, with all populations exhibiting comparable levels. This suggests inbreeding depression is not limiting recruitment in the Canadian population, as previously hypothesized. We also found high differentiation between populations and unique environmental conditions at the northern range margin. Consequently, efforts to bolster genetic diversity in the Canadian population are not presently warranted and should be avoided in the future.


title: Autonomous UAV Control for Low-Altitude Flight in an Urban Gust Environment

abstract: With rapid advances in the unmanned aerial vehicle (UAV) field and their growing popularity in a wide range of civilian and commercial applications, UAV operation in urban areas is inevitable. For small size UAVs conducting low-level flight in an urban landscape, wind disturbances pose a significant challenge. Ensuring safety while flying in proximity to buildings and other obstacles requires a thorough understanding of the nature of these disturbances and the expected performance of an autopilot in their presence. This study focuses on the position control of a quadrotor UAV in an urban wind environment. A literature review provides an in-depth survey of the state of the art in quadrotor flight control. Urban wind conditions are modelled around a single building through a Computational Fluid Dynamics (CFD) analysis using Large Eddy Simulation (LES). Modelled transient wind flow velocities are applied to create a realistic simulation environment for a custom built quadrotor prototype named TARA. Four different control techniques are selected and implemented for the autonomous position control of TARA. A precise simulation methodology is employed to ensure consistent flight testing under diverse representative wind conditions. The results are evaluated under a carefully crafted set of criteria and selected performance metrics. Based on the analysis, a hybrid control scheme is proposed, with simulation and experimental data confirming its improved ability in dealing with realistic urban wind disturbances with an average position hold within a single body length.


title: Bare-Metal Kernels for DEVS Model Execution in Embedded Systems

abstract:
With the rising popularity of embedded systems came challenges due to new application demands, increasing complexity and widening productivity gap. To deal with these issues, model-driven development promotes a higher level of abstraction and uses models as the primary artifacts. In fact, the fundamental principle is to construct a model of a system and then transform it into the real system.
We focus on DEMES, a model-driven approach based on DEVS, and especially the transition from simulated platform to execution platform. We present real-time executives that allow DEVS models to be executed on a target platform without the need of an operating system. In addition to the real-time executives, we introduce a hardware abstract layer that supports several hardware peripheral libraries and fosters fast prototyping. We also illustrate the DEMES-driven development cycle with a particular case study. Our contributions have resulted in a reduced footprint, increased performance and platform portability.


title: The Hammam:  The Restoration and Revitalization of Teheran's Qibla Hamman (The Khanum Hammam)

abstract: In ancient Persian culture, water is considered the holiest natural element, signifying purity, brightness and cleanliness. The public bath hammam is one of the most enduring buildings that we find in Iran. It is a place to cleanse the body, but it also serves as a centre for socialization; a cultural hub in each district. This thesis explores the Iranian public baths and their connection to urban heritage. The dissertation first contextualizes the concept of the hammam within the Persian tradition as an interactive cultural forum. A proposed set of ideas and standards meet the contemporary needs of the public and indicate ways in which they can benefit from - and allow for – the continuity of public baths in the future. The design proposal involves the restoration and revitalization of the Qibla Hammam (also known as the Khanum Hammam) In Tehran, a public bath from the Safavid dynasty (1501–1736).


title: Intent-Gesture Relationships for Collaborative Information Visualization

abstract: In this study we look at the relationship between gestures and intents when pairs of participants are collaborating around a large display with a graph. We aimed to find out what gestures paired with which intents, which gestures participants would find suitable for intents, and how our findings could influence designing graphs for collaborative analysis. We studied 8 pairs of participants and found 10 frequent gestures and 11 frequent intents. An exploration of the relationship between gestures and intents found 15 frequent co-occurrences. We analyzed these findings and then proceeded to discuss design suggestions and future work in the field.


title: Development of a Safety-Oriented Interaction Strategy and Compliant Limb Sensor System for a Gait Rehabilitation Robot

abstract: Robots are expanding into new fields through human-robot interaction, however this has created safety concerns due to collisions. This research develops the Safety-Oriented Interaction Strategy (SOIS) that detects collisions by measuring deformation of a compliant limb sensor (CLS) and yields using a zero force controller that directly feeds back CLS deformation. Using a 1DoF LTI model, controller stability was proven and the reduction of impedance and CLS deformation was analyzed. The effect of nonlinearities on the controller was simulated. Stiction was found to generate oscillations that could be eliminated by thresholding CLS feedback. The proposed controller displayed similar deformation and force reduction as admittance control during experiments while remaining stable. Potentiometer and optical based planar CLSs were prototyped and the potentiometer based CLS was more accurate (average errors <1mm/0.5 degrees). However, the potentially lightweight optical based sensor can follow general motion, and with refinement can be used in future designs.


title: Freeze-Thaw Sludge Dewatering and Stabilisation using Ferrate(VI)

abstract:
The study examined the individual and combined effects of potassium ferrate(VI) additions and freeze-thaw conditioning for the stabilisation and dewatering of wastewater sludges. The purpose of the research was to develop a simple and effective sludge management approach for remote communities in cold climates. Freeze-thaw sludge dewatering with gravity meltwater drainage reduced the sludge volume by up to 88%, and resulted in approximately 2.4-log inactivation of fecal coliform. For many of the test samples, increasing the time frozen from 1 to 15 days increased the level of inactivation of fecal coliform. However, some samples demonstrated >3-log inactivation of fecal coliform after only 1 day frozen, which suggests that fecal coliform inactivation occurs primarily as a result of the freezing process. Similarly, the freezing temperature did not have a significant effect on the level of inactivation, and increasing the duration of time spent frozen from 1 to 15 days did not improve sludge drainability during thaw, which indicates that particle consolidation, leading to improved sludge dewaterability, occurs during the freezing process.
Potassium ferrate(VI) additions followed by a 15-minute reaction period oxidised sludge constituents, which inactivated fecal coliform, reduced the concentrations of odour causing compounds (ammonia and sulphide), and solubilised sludge solids, resulting in an increase in soluble chemical oxygen demand (sCOD), soluble proteins and soluble carbohydrates. Potassium ferrate(VI) additions as low as 1.0 g/L also reduced the concentrations of hormones in sludge.
Co-treatment of anaerobically digested sludge using 5.0 g/L of potassium ferrate(VI) followed by freeze-thaw with gravity meltwater drainage reduced fecal coliform to <100 colony forming units (CFU)/g dry solids (DS), and dewatered the sludge to >12% total solids (TS), representing an 85% reduction in sludge mass following a 12-hour thawing period. The sludge cake remaining was suitable for land application in terms of fecal coliform under the level 1 criteria for pathogens (CP1) (Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), 2013). Additionally, raw primary sludge was treated and dewatered to below CP2 limits using 5.1 g/L potassium ferrate(VI) followed by freeze-thaw with gravity meltwater drainage, and to below CP1 limits using <15 g/L pre-treatment followed by freeze-thaw.


title: On Relationality in Virtue Ethics: Accounting for Injustices in a Global Context

abstract: This thesis utilizes a virtue ethics framework to engage with the effects of global oppression and injustice on the selves of moral agents to provide an account of how to be virtuous in our non-ideal world. I outline several virtue ethics frameworks and highlight Lisa Tessman’s account in Burdened Virtues (2005). Her account analyzes the harms of oppression in new ways. I outline four criticisms of her account and respond to each by arguing for an enhanced virtue ethics framework that incorporates a relational conception of the self. Through the understanding of human beings as fundamentally relational and interdependent, I provide an account of virtue ethics that moves beyond Tessman’s. I argue for the sorts of virtues that emerge from this account, including the virtue of responsibility and an enhanced practical reasoning. These virtues assist agents to respond to others in morally appropriate ways and ensure collective well-being.


title: I Used to Speak in Tongues: Spirituality and Pentecostal Deconversion Narratives

abstract:
This dissertation examines Pentecostal deconversion narratives in memoirs by Kim Barnes and Dennis Covington, in novels and short stories by Lee Smith, and in promotional interviews with Katy Perry and Megan Fox. They feature protagonists who grow out of Pentecostalism. In most cases, they are young girls who are raised in Pentecostal homes and leave their homes and religions at the same time. In place of Pentecostalism, the protagonists adopt a spirituality that is either liberal or neoliberal. Liberal spirituality encourages experimentation and assimilation of various religious practices and beliefs as long as they complement classic liberal values like individualism, freedom, rationality, pluralism, etc. Neoliberal spirituality is very similar, but it redefines the classic liberal values with a market sensibility so that freedom becomes freedom in the market, and rationality becomes self-interested rationality based on cost/benefit analysis. In most cases, these protagonists’ spiritualties fall somewhere on a continuum between liberal and neoliberal extremes. The narratives privilege these spiritualties as more modern, more empowering, and more in keeping with contemporary American values. They also help position the authors as people who are educated, modern, and liberal in their approach to religion. By contrast, the conservative theology and ecstatic religious practices of Pentecostals are represented as oppressive, narrow minded, dogmatic, and most of all, irrational. By extension, Pentecostals themselves are underdeveloped, uneducated, and anachronistic. In fact, while conservative Protestants as a whole occupy an “othered” position in relation to both liberal and neoliberal spirituality, Pentecostalism becomes the epitome of “bad religion” because it embraces ecstatic experiences.
These narratives serve three compatible purposes: 1) they promote and celebrate liberal and neoliberal approaches to religion; 2) they help establish and solidify a religious/spiritual identity for the author, and by extension, membership within a religious/spiritual community (although it is an amorphous, undefined community); and 3) they provide access to a large “spiritual but not religious” audience, which embraces consumerism. To accomplish all three of these aims, the narratives use Pentecostalism and Pentecostals as a foil, a caricatured other onto which they project exaggerated negative traits.


title: Force Sensing Insole for a Balance Enhancement System

abstract: This thesis presents the design and evaluation of an insole for measurement of the complete ground reaction forces and center of pressure that can be integrated on a balance enhancement system. The insole was prototyped using rubber and a number of small force sensing elements. A calibration procedure was implemented for the sensors to calculate the vertical load and an artificial neural network model was implemented on training data to predict shear loads. Experiments with healthy subjects were conducted to evaluate the performance of the insole on both standing and walking conditions. The results show the insole is capable of measuring the vertical component of the ground reaction force with good accuracy compared to a force plate, and the neural network was able to produce an estimate of the shear forces. The insole is capable of measuring the variations of the center of pressure on different standing and walking conditions.


title: Development of economic and reliable tool for condition survey and middle management of asphalt pavement

abstract:
Rehabilitation and maintenance of pavement are well established and costly operations. One of the major challenges of these operations is determining the optimum maintenance and repair schedule. In any given city, there are hundreds of miles of pavement constructed at different times and are in different states of deterioration. It is the job of municipal engineers to establish a cost effective schedule that prioritizes the repair or even the reconstruction of different segments of the roads. The schedule is usually based on an overall Pavement Condition Index (PCI). Typically, inspectors are sent out to observe the pavement conditions and conduct accurate measurements to be used in computing the PCI; however the cost associated with such inspection missions is often high.
This thesis proposes a novel approach to estimate a cost effective Pavement Indicator (PI) for the entire city (or any area of interest). The proposed approach exploits newly available miniature cameras, GPS, wireless networking and Digital Signal Processing to automatically and continually collect visual information about different segments of the road, and combines these images to establish a live map of the city roads where different colours correspond to an approximate estimate of a pavement indicator (PI). The proposed technique is not a replacement of the traditional inspection, but rather it is a tool to identify the sections that are in greater need of repair. The technique involves taking pictures of various sections of the road network using cameras mounted on public vehicles and transmitting these images to a processing centre. Each image is processed using image filtering techniques to produce an initial estimate of PI. The cumulative effect of these estimates produces regional estimates that become more statistically accurate as time goes by, and the overall PI map is continually updated to maintain a global visual map of PI. The proposed pavement indicator (PI) map can then be linked to an optimization software package to determine the most cost effective road rehabilitation schedule.


title: The Usability of Captchas on Mobile Devices

abstract: Completely Automated Public Turing tests to tell Computers and Humans Apart (captcha) are challenge-response tests used on the web to distinguish human users from automated bots. Mobile devices such as smartphones and tablets have become a primary means of accessing online resources for many users, however most existing captchas do not properly fit mobile devices and may lead users to abandon tasks. Captchas have become sufficiently hard for users to solve that some web sites refrain deploying them and others are actively looking at alternatives. For users of smartphones, the reduced screen size can lead to typing mistakes and loss of position. In addition, environmental context and device orientation also have an impact on the user experience. In this thesis, our research revolves around three primary, inter-related questions: How can we effectively assess usability issues of captchas accessed on smartphones? What are the most prevalent usability issues of captchas accessed on smartphones? How can we improve captchas for smartphone usage? We conducted lab and heuris- tic evaluations on existing and prototype captcha schemes, and identified areas for improvement. We developed, refined and tested a set of domain specific heuristics to evaluate captcha schemes on smartphones. We designed and tested four captcha prototypes to assess the viability of different input methods. From the empirical work, we identified design strategies for the development of new captcha schemes for smartphones.


title: A Threat to Order: A Voegelinian Exploration of Modernity, Spiritual Crisis, and Resistance

abstract: The purpose of this thesis is to explore the spiritual crisis that arises because of a disjunct between the symbols that are of the highest concern to an individual society and the overarching Liberal symbols which inform broader narratives. Using Eric Voegelin’s theory of representation, this discussion will weigh the consequences of imposing dogmatic “gnostic” approaches against claims that adherence to a single set of symbols is the best way to mitigate conflict and avoid future insecurity. This discussion will analyze the spiritual crisis that arises from pressure to embrace a particular overarching metaphor and the possibility that this spiritual crisis may manifest in the form of a resistance identity, and, furthermore, conflict.


title: Can a Dynamic Risk Instrument Make Short-Term Predictions in "Real Time"? Developing a Framework for Testing Proximal Assessment of Offender Recidivism Risk During Re-entry

abstract: Correctional psychologists have classified risk factors for criminal recidivism into static (non-changing, non-improving) and dynamic (theoretically changeable) domains. By definition, a dynamic risk factor is a variable that can change across time, and as it changes, offenders’ likelihood of recidivism must logically change in the same direction. Thus, a measure that assesses dynamic risk factors repeatedly across time is hypothesized to provide evidence that more proximal re-assessments have greater predictive validity for short-term reoffending outcomes, compared to prior, more distal assessments. This dissertation develops and proposes a framework for testing the proximity hypothesis with longitudinal, multiple re-assessment re-entry data, and argues that Cox regression survival analysis with time-varying predictors is an appropriate statistical model for comparing the relative value of ratings taken later in the follow-up period, compared to baseline ratings taken at the time of release from incarceration. In this dissertation, the proposed three-step framework was applied to a large dataset of paroled offenders in New Zealand who were assessed by their supervision officers on a regular basis (N = 3694 offenders represented by N = 97,185 assessments on a measure of theoretically dynamic risk factors). Results demonstrated consistent support for the conclusion that re-assessment improves predictive validity, specifically by showing (a) incremental prediction of re-assessments over baseline scores, and (b) incremental prediction of the most proximal assessment compared to averages of earlier scores. Effect size indices (time-dependent area under the curve [AUC] statistics) temper the interpretation of these results by showing that predictive accuracy was only sometimes enhanced to a statistically significant degree when including re-assessments in the model. Still, the results encourage community supervision correctional agencies to consider employing repeated measurement of offender clients using a dynamic risk instrument. It is also recommended that researchers consider using the proposed framework as a logical approach to verifying the underlying assumption that purportedly dynamic risk factors are both dynamic, and accurate markers of fluctuations in individuals’ risk to re-offend.


title: Evolution of Pile Shaft Capacity over Time in Soft Clays (Case Study: Leda Clay)

abstract: This thesis presents a comprehensive experimental investigation to examine the evolution of pile shaft capacity over time. This phenomenon is observed in piles driven into soft clays, which referred to as pile set-up/freeze. The first phase investigates the behavior of pile-soil interface over time using a modified direct shear test at two loading rates of slow and fast. The second phase involved a series of pile load testing was performed on steel and concrete piles driven into Leda clay in a test site. The piles were tested immediately after driving to measure their initial bearing capacities, and were tested repeatedly over different elapsed time to study the change in pile shaft capacity. The excess pore water pressure around the pile was also monitored by a sensor. The average pile capacity measurements indicated that there is approximately 4.5-5.5 times increase in the pile capacity after 30 days from the initial day.


title: The Content, Contextualization, and Effectiveness of Writing-Assignment Instruction Documents

abstract: This study of writing-assignment instruction documents (WAIDs) uses concepts from Rhetorical Genre Studies to examine WAIDs as a rhetorical genre by exploring the information that WAIDs contain, their contextualization within the university classroom, and how they situate users within that context. Further, it compares instructor and student perceptions to infer how WAIDs can most effectively communicate instructors’ expectations for assignments and foster quality writing. My analysis of (a) WAIDs from 11 sophomore courses, (b) interviews with students and instructors from two sophomore courses, (c) WAIDs from those two courses, and (d) students’ assignments written with those WAIDs suggests the following: WAIDs contain up to twelve categories of information, reinforce classroom roles, and set boundaries for student action, and yet students may see WAIDs as supplementary to in-class discussion of instructors’ expectations for assignments. Also discussed are differences between the two sophomore classes in students’ recognition of expectations for writing assignments.


title: A Quasi-Thermal-Mechanical-Biological Model of the Ste-Sophie, QC Landfill

abstract: A landfill located in Ste-Sophie, QC was instrumented with sensors measuring temperature, oxygen concentration, and settlement. A quasi-thermal-mechanical-biological conceptual model was developed and a corresponding numerical model was set-up in COMSOL Multiphysics to simulate the temperatures within the vertical waste profile. Thermal conductivity was varied with depth and time in the waste profile. An aerobic heat generation model was proposed that related the aerobic heat generation rate to the oxygen concentration measured near the surface. An anaerobic heat generation model presented in the literature was included in the model. The heat generation rate was dependent on waste temperature and the total energy expended. Corresponding field data were collected and the simulated temperatures were in good agreement with measured field temperatures. A heat budget was computed showing that aerobic and anaerobic heat generation accounted for 36% and 64% of total heat generation, respectively, during the filling stages of landfill operation.


title: Tissue Plasminogen Activator (tPA) Promotes Postnatal Cortical Neuron Survival in Vitro Via JAK2- and mTOR-Dependent Mechanisms

abstract: Tissue plasminogen activator (tPA) is the only approved drug for ischemic stroke in Canada but is limited in its clinical efficacy due to its short therapeutic window. This study sought to determine the effect of tPA on postnatal primary cortical neuron viability and aimed to identify the relevant cellular signalling mechanisms underlying the tPA-mediated effects in vitro. The data revealed that tPA significantly increased the propensity for cell survival within a time latency window of up to 3 hours. tPA-induced neuroprotective effects were significantly dependent upon the mTOR and JAK/STAT signalling pathways, while the MEK and PKA signalling pathways were found to play a less critical role. Immunocytochemical staining showed a marked increase in p-S6 expression following treatment with tPA, substantiating the vital role of mTOR activation in tPA-mediated neuroprotection. These results suggest the possibility of targeting the defined mechanisms to expand the therapeutic window of tPA in stroke recovery.


title: Agonism and Antagonism: Past and Future Possibilites of Radical Democracy

abstract: Though radical democratic theory has become a mainstay in progressive political thought, it is clear that more work needs to be done in terms of establishing the empirical bases for its appearance and continuation. As such, through a comparative investigation and analysis of historical episodes of political contestation that reflect those encouraged by radical democratic theorists such as Chantal Mouffe, William Connolly, Bonnie Honig, and Jacques Rancière, this works looks to establish the circumstances in which such episodes are able to take an agonistic form. In establishing them and in analyzing their impact on the authors’ vision, suggestions for theoretical amendments are put forth for the purposes of strengthening the radical democratic project.


title: Evaluations of Rape: Investigations Using Implicit and Explicit Measures, Online Research Methodology, and Samples of Community Men

abstract:
Evaluations of rape theoretically play an important role in sexually aggressive behaviour (e.g., Nunes, Hermann, & Ratcliffe, 2013). The purpose of this dissertation was to explore the relationship between implicit and explicit evaluations of rape and sexually aggressive behaviour using a longitudinal research design online. Study 1 examined the use of a self-generated identification code (SGIC) to track participants anonymously online. Study 1A examined a six question SGIC in a sample of 168 students and found the SGICs produced unique identifiers, and a low, but acceptable, exact match rate across a one month period. Study 1B explored a 12 question SGIC with a sample of 30 students and 15 community participants. The 12 question SGIC also produced unique identifiers, and resulted in a low, but acceptable, exact match rate across a one week period. These results suggest the 12 question SGIC can be used in longitudinal research online.
Study 2 explored the cross-sectional relationships between implicit and explicit evaluations of rape and sexually aggressive behaviour using a sample of 150 male students and 378 community men. In both samples, explicit evaluations of rape had moderate to strong positive relationships with sexually aggressive behaviour. The same pattern of results was not observed for implicit evaluations of rape.
Study 3 examined the relationship between implicit and explicit evaluations of rape and sexually aggressive behaviour using a longitudinal research design. Study 3 Wave 1 replicated and expanded on Study 2 using a sample of 190 male students and 597 community men. Importantly, four different measures of implicit evaluations of rape were used. The same pattern of results as observed in Study 2 was found. Participants in Study 3 Wave 2 were 248 community men who had completed both Waves 1 and 2. Implicit and explicit evaluations of rape at Wave 1 significantly predicted self-reported sexually aggressive behaviour at Wave 2. These findings suggest that both implicit and explicit evaluations of rape may be relevant for sexually aggressive behaviour. If replicated, these results have important implications for theory, research, and correctional practice.


title: Scaffolding Democracy:  Democracy as the Impossible Project of Architecture?

abstract:
This thesis will address forms of citizenship and political expression – their architectural and urban implications - as possible outcomes of democratic manifestations. In the context of austerity measures and their corresponding movements of resistance, spatial agency will be evaluated for the potential to design spaces that accommodate conflict and discussion.
Beginning with a study of the theories touching on democracy, activism and spatial justice, the argument will then be framed through notions such as dissensus, agonism, property, surveillance and citizenship, which will be evaluated against the context of Neoliberalism’s crisis in the contemporary city.
The outcome will be a project proposal for Montreal's underground network, which could legitimize dissent and offer a socially driven architectural platform for urban action and expression. Can architecture promote civic engagement? Is democracy the impossible project of architecture? These are the critical questions this thesis will address.


title: The Anxiety of Architecture: Design Uncertainty in a Subjective World

abstract:
In the Post-Modern era of divisive critical discourse where theory is no longer willing to pursue the goal of absolute truth, architecture is uncertain. Without the certainty of absolute knowledge, the hope for any objective understanding of architecture is gone. In its place lies a turbulent realm of subjective experience.
This thesis undertakes an exploration of that uncertainty in architecture. Through a reading of Graham Harman’s Object Oriented Ontology, this thesis considers how the philosophy of realism can inform the architect on understanding and working within the bounds of a world where subjective experience rules. This understanding is then challenged through a reflection on the task of designing a contemporary building sympathetic the character of the Centretown Heritage Conservation District of Ottawa, Ontario. Out of the exploration of that task the thesis’s project of a mixed-use infill development is arrived at.


title: Preclinical Evaluations of the Blend Extract of Souroubea Sympetala and Platanus Occidentalis in Rats: Proposal of a Potential Novel Treatment for Post-Traumatic Stress Disorder

abstract: Post traumatic stress disorder (PTSD) is characterized by an inability to extinguish fear memories. If left untreated, PTSD typically follows a chronic, unremitting course culminating in significant impairments of psychological and emotional functioning. Current treatment approaches for PTSD generally yield only symptomatic improvement, thus other avenues must be explored. This thesis was aimed at investigating the use of a blend extract of a 1:1 Souroubea sympetala and Platanus occidentalis (Sycamore tree) as a potential novel treatment for PTSD, which may act by blocking the reconsolidation of fear memories. During reconsolidation, formed memories are rendered labile during reactivation, providing a window of opportunity for pharmacologically manipulating formed fear memories. In the present thesis, the efficacy of reconsolidation blockade of short-term (4h) as well as long term (24h and 9 days) fear memories through treatment with the blend extract (7mg/kg), diazepam (1mg/kg) and vehicle was measured through the Fear Potentiated Startle paradigm.


title: Evolutionary Neural Network-Based Obstacle Avoidance for a Planetary Exploration Rover

abstract: During space missions, a planetary exploration rover is subject to two main communication issues being the distance and orbital difference between Earth and the target planet, the communication transmission delay and the limited transmission window. The proposed autonomous path planning system presents a set of genetically evolved neural network controllers for local path planning of a mobile robot. Each evolved network is adopted to direct the rover travelling in one category of partitioned environments achieving a sequence of targets with obstacle avoidance. With a set of pre-learned networks, the rover would be adaptable to traverse in new environments of specific category. Genetic algorithm is used to obtain the evolved network by developing behavior strategies through evolutionary iterations. Simulation results indicate that evolved neural controller can adapt to novel environments and generate satisfying path for the rover in a computationally economic manner.


title: Does the Lake Huron Shoreline Influence Distributions, Altitudes, and Flight Directions of Nocturnally Migrating Birds?

abstract: Increasing numbers of wind turbines are being installed around the Great Lakes, but it is not known whether placement of turbines near shorelines might increase collision risks to passing bird migrants. I assessed numbers of nocturnal migrant birds and their flight behaviour using five marine radars at various distances from Lake Huron between April 18th and May 31st 2014. The numbers of birds detected varied greatly among nights ranging from a few thousands to hundreds of thousands per night. There were small differences in the numbers of birds detected among sites, but no consistent differences between shoreline and inland sites. The flight altitude and flight direction of birds detected also varied among nights but there was again no strong indication that they are influenced by the shoreline. Overall, I did not find evidence that locating wind turbines along shorelines would increase the risk of collisions to passing migrants.


title: Characterization of Cement Paste in Fresh State Using Electrical Resistivity Technique

abstract: The impedance spectroscopy technique was used to monitor the electrical resistivity of various cement paste mixtures during first 2 hours after mixing before the setting time. The conductivity and pH of the pore solutions extracted from fresh cement paste mixtures was also determined. The conductivity of pore solution extracted from select hardened paste mixtures cured in sealed moisture condition was also obtained. These data were used to investigate the various influential parameters such as (1) the effect of time on the electrical resistivity, (2) the effect of supplementary cementitious materials and chemical admixtures on the electrical resistivity, (3) the effect of w/c ratio on the electrical resistivity, (4) tortuosity and the relationship between electrical resistivity of paste and pore solution and (5) correlation between the pH and electrical conductivity of pore solution. In addition, a numerical model was proposed to estimate the conductivity of pore solution in fresh state.


title: Simulation and Modeling of Underwater Acoustic Communication Channels With Wide Band Attenuation and Ambient Noise

abstract: Underwater acoustic communication uses acoustic waves to transmit and receive data under the water. Simulation of underwater acoustic communication is challenging due to impairments, including attenuation, multipath propagation, noise and Doppler spread. In this thesis, several solutions are proposed and compared considering multipath attenuation and ambient noise. These solutions are divided into two groups. One group is in the time domain and the other is in the frequency domain. The approaches in the time domain and frequency domain all take into account the attenuation calculation along with white and colored noise. Not only incoherent but also coherent attenuation are implemented. The bit error rate versus energy per bit to noise power spectral density ratio (Eb/N0) is applied for evaluation. The main conclusion of this work is that the coherent models with colored noise in frequency domain are more similar to the situation of real environment.


title: Taxing Away Citizenship: Do American-Canadian Dual Citizens Consider Their Status to be an Inconvenience?

abstract: Despite growing tolerance of dual citizenship in an era of globalization, this status continues to be problematized by the governments of both the United States and Canada. This is evident in recent changes to Canadian Bill C-24, in which new grounds have been established to revoke the Canadian citizenship of ‘dual citizens,’ and by recent political discourse, which depicts dual citizens as Canadians of ‘convenience’ with ‘thin’ attachments to the nation. This thesis explores how dual citizenship may instead be ‘inconvenient’ for particular citizen subjects, namely ‘American-Canadians.’ To demonstrate this, twenty-three narratives of current and former ‘American-Canadian’ dual citizens were analyzed. It would seem paradoxical to suggest that an individual with a robust citizenship on each end of the hyphen could experience inconveniences. Nonetheless, I will demonstrate how the citizenship-based tax laws of the United States create insecurities for this population and lead to impulses to renounce this ‘robust’ citizenship.


title: Development and Evaluation of Anti-corrosion and Anti-bacterial Polymer Coatings for Circulation Coins

abstract: This thesis is about developing and evaluation a protection coating for circulation coins that has anti-corrosion and anti-bacterial functions. Five candidate materials are selected, and only advanced liquid glass and polyurethane are ideal for both quarters and loonies. Among the two, only advanced liquid glass has anti-bacterial function. In this case, it is the most ideal material to protect the coins.


title: Edge-Preserving Image Upsampling and Image Warping

abstract: The goal of this thesis is to produce sharp and stylized upsampled images. We present cumulative range geodesic filter and bilateral roundup filter, with the former excels at edge sharpening and the latter finds a better balance between edge sharpening and fine-detail preservation. Moreover, we propose a pixel migration idea that relocates pixels in the image plane. We implemented pixel migration using a mass-spring physics simulation. In the context of image upsampling, we assign short rest lengths to pixels along edges, thus the gaps between those pixels are closed, and edge sharpness is recovered. Applying pixel migration on the original image plane, we propose a two-stage approach to painterly rendering of photographs, where the image plane is first warped to produce a distorted or caricatured effect and then the resulting image is rendered with a painterly effect. This work on image warping is published in Expressive, 2015.


title: Effects of farmland heterogeneity on pollination potential of agricultural landscapes in Eastern Ontario

abstract: Increasing farmland heterogeneity (spatial heterogeneity of crop cover) may enhance the pollination potential of agricultural landscapes, without taking arable land out of production. We tested the predictions that increasing the compositional heterogeneity of crop cover (measured as increasing crop diversity) and/or increasing the configurational heterogeneity of crop cover (measured as decreasing mean field sizes) will increase pollination potential of agricultural landscapes. We deployed flowering, self-incompatible plant species in landscapes selected to minimize the correlation between crop diversity and mean field size, and used their reproductive success as a metric for the pollination potential. We did not find any support for the prediction that increasing crop diversity and/or decreasing mean field size increased pollination potential of agricultural landscapes. Based on our results, we suggest that policies aimed at increasing farmland heterogeneity may not enhance pollination services in agricultural landscapes.


title: Effects of Farmland Heterogeneity on Bat Species Richness and Abundance in Agricultural Eastern Ontario

abstract: Within agricultural landscapes higher amounts of semi-natural habitat and fragmentation of forest appear to have positive effects on bat species richness and activity, however the way crops are arranged (configurational heterogeneity) or their diversity (compositional heterogeneity) may also have a role. Smaller field sizes should increase both the accessibility and quality of foraging habitat. The diversity of crop types may also benefit bat communities by creating more diverse, abundant, and temporally stable communities of prey insects. We conducted acoustic surveys in agricultural landscapes in Eastern Ontario to test the predictions that bat species richness and activity should increase with increasing compositional and configurational heterogeneity of crops. Field size appeared to have mixed effects on bat activity levels. Total bat activity and activity of several species was higher in landscapes with higher diversity of crops. We hypothesize this is because diverse crops create more temporally stable prey communities.


title: Influence of male mating history on female mate choice in the Trinidadian guppy

abstract: The phenotype linked fertility hypothesis proposes that sexual selection should favour females who can accurately assess the fertilization potential of available mates and preferentially avoid mating with males who may be sperm depleted so as to minimize the risks associated with reproduction. I investigated experimentally whether females of the Trinidadian guppy are able to assess male functional fertility using a wide range of sensory cues and choose to avoid mating with males who may be sperm limited. On average, females avoided males that were apparently previously mated or actually sperm depleted, while exhibiting a strong preference for the other non sperm depleted male. Both visual and chemical cues from males appear to reveal their potential functional fertility and such cues were used by females to discriminate between sperm depleted and non sperm depleted males. My novel results are important as they support the above stated hypithesis.


title: Oxytocin and Social Sensitivity: Implications for Vulnerability to Stress and Depressive Symptoms

abstract: Oxytocin is a neuropeptide that has been implicated in several prosocial behaviors, such as trust, empathy and social affiliation, and might contribute to mental health disorders marked by social disturbances. Indeed, Chapter 1 indicated that the accumulated evidence points to interactions between oxytocin, and various neuroendocrine, neurotransmitter, and inflammatory processes in the emergence of depressive disorders. However, the perspective was discussed that oxytocin does not uniformly enhance prosocial behaviors, but instead increases the salience of social cues, so that positive and negative events might elicit exaggerated responses that influence affective states. The current studies examined the role of oxytocin in relation to various stressors and mental health outcomes. In Study 1 (N = 288), it was determined that a genetic variant on the oxytocin receptor gene (OXTR) moderated the influence of early-life events in relation to later depressive symptoms. In the absence of this polymorphism individuals who experienced early-life maltreatment displayed high levels of depressive symptoms, but this was not evident in the presence of this polymorphism. In essence, in the absence of the polymorphism, prosocial behaviors are present, but so is social sensitivity, potentially rendering individuals more vulnerable to the effects of early-life adversity. Study 2 (N = 128) revealed that individuals carrying the same ‘prosocial’ genetic variant on the OXTR were more emotionally sensitive and biologically reactive to social ostracism, further supporting the social sensitivity view. Consistent with this, in Study 3 (N = 243), individuals carrying a genetic variant on a gene that controls for oxytocin release (CD38 gene), which had previously been viewed as a ‘protective’ variant, displayed poorer peer and parental relationships and enhanced suicidal ideation. Finally, Study 4 (N = 67) revealed that although oxytocin was inversely related to distrust scores and baseline cortisol levels, this hormone was unaffected by a stressor or the presence of social support. These studies highlight the role of oxytocin in stressor responses, social sensitivity and, in turn, vulnerability to mental health outcomes. At the same time, the data also suggest that interpreting the findings solely on the basis of a prosocial framework may be too narrow.


title: Being Irish on the Prairies:  Repertoire, Performance, and Environment in Oral History Narratives of Winnipeg Irish Canadians

abstract: This thesis applies Diana Taylor’s concept of repertoire to oral history interviews with ten first generation Irish Canadians living in Winnipeg who emigrated between 1957 and 2012. It argues that traditional performances, such as music and dance, have acquired a provenance with particular histories. This has made them both meaningful and politically contentious expressions of Irish identity. Memory tensions emerged when the performances were integrated into a new repertoire in Canada. Taylor’s concept is modified and applied to embodied encounters with landscape and weather. As experiences of a new place are incorporated into a spatial repertoire, they become infused with emotional significance, and emigrants’ stories about visiting Ireland, surviving Manitoban winters, or driving across flat prairie spaces, communicate feelings of displacement and belonging. Accompanying this thesis is a website which further explores emotional memories in these interviews through an audio exhibit (www.beingirishontheprairies.ca).


title: PostureChair: A Real-Time, As-Needed Feedback System for Improving the Sitting Posture of Office Workers

abstract: Computer users spend the vast majority of their time sitting, and poor posture in the workplace is an endemic issue. This work presents PostureChair, a posture detection system that uses contextual digital feedback to persuade users to improve their sitting posture. Two types of digital feedback, with varying amounts of information, were compared through a repeated measures study to determine how much information is necessary to improve posture and to appeal to the user. The results of the study showed participants’ sitting posture improved significantly with both feedback types when compared to their posture with feedback disabled. Participants overwhelmingly preferred the more detailed feedback even though it did not clearly improve users’ sitting posture beyond the simpler feedback. The PostureChair system was well received and demonstrates that contextual posture improvement is an effective and much-needed addition to the workplace.


title: Biologically-Active Secondary Metabolites of Foliar Endophytes of Conifers and the Understory Species Rhododendron Groenlandicum from the Acadian Forest

abstract: Cronartium ribicola, the causative agent of white pine blister rust is damaging to all five-needle pine species. Existing methods of treatment are largely ineffective, resulting in the need of more innovative approaches. Studies have shown that some conifer endophytes produce compounds that display potent antifungal activity, including towards haploid cultures of C. ribicola. Three conifer endophyte species were studied here. Compounds 1 – 4, (1’Z)-dechloromycorrhizin A (1), mycorrhizin A (2), chloromycorrhizin A (3) and the new natural product 3-chloro-4-[(1Z)-1’-chloroprop-1’-en-1’-yl]-9-hydroxy-8,8-dimethyl-9,4,5,8-tetrahydro-2H-1-benzopyran-5,2-dione (4) were isolated from L. papyraceum. Compounds 5 and 6 were produced by D. celastrina and were both identified as phomosolide A and a stable pyrone moiety of phomopsolide A respectively. The remaining compounds 2-(7-methoxy-2,5,6-trimethyl-4-oxo-4 H-benzo[d][1,3]dioxin-2-yl)propanoic acid (7), (E)-6-((3’-carboxybut-2’-en-2’-yl)oxy)-4-methoxy-2,3-dimethylbenzoic acid (8) and 2-(6-(hydroxymethyl)-7-methoxy-2,5-dimethyl-4-oxo-4H-benzo[d][1,3]dioxin-2-yl)propanoic acid (9) were isolated from S. foliicola and are novel metabolites. All compounds possessed antimicrobial activity in B. subtilis, E. coli, S. cerevisiae and M. violaceum assays.


title: Dose-Response Modeling for Ordinal Outcome Data

abstract: We consider the characterization of a dose-response relationship when the response variable is ordinal in nature. Initially, we review the existing models for describing such a relationship, and propose an extension that allows for the possibility of non-zero probabilities of response for the different categories of the ordinal outcome variable associated with the control group. We illustrate via a simulation study the difficulties that can be encountered in model fitting when significant background responses are not acknowledged. In order to further enlarge the spectrum of dose-response relationships that can be accurately modeled, we introduce splines into the existing models for ordinal outcome data; demonstrating in a simulation that such models can provide a superior fit relative to existing ones. We also propose an alternative reference dose measure for ordinal responses. Specifically, we propose an alternative method for defining the benchmark dose, BMD, for ordinal outcome data. The approach yields an estimator that is robust to the number of ordinal categories into which we divide the response. In addition, the estimator is consistent with currently accepted definitions of the BMD for quantal and continuous data when the number of categories for the ordinal response is two, or become extremely large, respectively. We suggest two methods for determining an interval reflecting the lower confidence limit of the BMD; one based on the delta method, the other on a likelihood ratio approach. We show via a simulation study that intervals based on the latter approach are able to achieve the nominal level of coverage.


title: A Toxicogenomics Study of the Hepatocarcinogen Furan

abstract: A major goal in human health risk assessment is the identification and management of chemicals that may cause cancer in human populations. The current gold-standard for assessing chemical carcinogenicity is the two-year rodent cancer bioassay, which is animal, time, and resource intensive. The use of toxicogenomics for chemical risk assessment was first proposed over 15 years ago because of its potential to produce toxicologically relevant data more quickly, using fewer animals, and at a lower cost than the two-year cancer bioassay. While the two-year cancer bioassay produces a detailed inventory of chemical-dependent lesions, toxicogenomics analyzes chemical-dependent changes to global gene expression. Moreover, toxicogenomics provides comprehensive mechanistic data that are not obtained using standard tests. In this thesis quantitative, predictive, and mechanistic approaches were applied to a toxicogenomic case study of the rodent hepatocarcinogen furan. Female B3C6F1 mice were exposed for three weeks to non-carcinogenic or carcinogenic doses of furan. The dose response of a variety of transcriptional endpoints produced benchmark doses (BMDs) similar to the furan-dependent cancer BMDs. Bioinformatic analysis of disease datasets showed strong similarity between global gene expression changes induced by furan and those associated with the appropriate hepatic pathologies. The molecular pathways that were enriched in the liver following furan exposure facilitated the development of a molecular mode of action (MoA) for furan-induced liver cancer. Finally, transcriptional changes in formalin-fixed and paraffin embedded (FFPE) samples were compared to high quality frozen samples in order to evaluate whether archival samples are a viable option for toxicogenomic studies. The advantage of using FFPE tissues is that they are very well characterized (phenotypically); the disadvantage is that formalin degrades biomacromolecules, including RNA. FFPE samples as old as three decades were shown to be feasible for toxicogenomics studies using a ribo-depletion RNA-seq protocol. Taken together, this case study demonstrates the utility of toxicogenomics data in human health risk assessment and the potential of archival FFPE tissue samples, and identifies viable strategies toward the reduction of animal usage in chemical testing.


title: Development of a Graphical User Interface Presenting Turbulent Airflow Over A Flight-Deck For Improved Situational Awareness For Helicopter Pilots in Challenging Wind Conditions

abstract:
The intent of this study is to provide the helicopter operators a presentation of the airflow over the flight deck prior to the approach Phase Of Flight (POF). This capability has the potential to influence the decision making associated with the approach. Turbulent airflow visualization designs were created focusing on user centered design principles and usability heuristics. The designs were presented to experienced helicopter pilots and subjectively evaluated by the same pilots. Based on the evaluation results, a dynamic three dimensional (3D) design was selected for development of a Shear-Stress Transport (SST) turbulence model using the Simplifed Frigate Shape 2 (SFSll) geometry. The 3D model was created for further testing in a simulator.
The findings show interest exists within the helicopter pilot community for a capability to have identified where hazardous airflow is located over the flight deck and a more in-depth awareness of what the airflow is doing is desired.


title: Evaluating trivalent chromium (CRIII) toxicity on wild terrestrial plants

abstract: Elevated chromium levels in soil from mining can impact the environment, including plants. Extensive chromite-ore deposits have been discovered in the Ring of Fire region, thus mining may increase. Chromium toxicity on wild plants is poorly understood. Concentration-response experiments were conducted to evaluate the effects of chromium on terrestrial plants. Using artificial soil, seeds of 32 species were exposed to chromium (CrIII) at concentrations (0-1000 mg/kg) simulating contamination levels. Many plants were not affected at low concentrations, yet higher concentrations were harmful to all species. Secondly, seedbank soils were collected in four habitats near the Ring of Fire and were exposed to chromium at equivalent concentrations as before. More seeds germinated from the lakeshore, with reductions in species/seedlings numbers as chromium increased. This was similar for the upland. This study represents the first step in understanding effects of chromium on plants and could form the basis for risk assessments.


title: Math Anxiety: Not Just a Numbers Game

abstract: Math anxiety can influence career choices, result in difficulties in everyday situations involving numbers (e.g., financial decision making) and has been linked with performance deficits on a variety of mathematical tasks. The roles of the classroom environment, societal stereotypes and negative math attitudes have all been associated with math anxiety. Current research suggests that children are developing math-related anxiety at a very young age, leading some researchers to propose that foundational number skills may be related to the development of anxiety about math. The goal of the present study was to develop a clearer, more integrated understanding of the cognitive influences (i.e. attentional, spatial and quantity skills) on math anxiety and math performance. The results showed that math anxiety in adults is not related to deficits in the foundational number skills. Instead, both quantity skills and math anxiety uniquely contributed to variance in math performance.


title: Pearl Harbor and American Intelligence Culture: Cultural Symbols in American Intelligence Discourse Communities, Meta-Theoretical Lenses and Multi-Perspective Approaches

abstract: Ideas of the world persist long beyond the contexts that gave rise to them. In intelligence, as in strategic culture, these persisting ideas form a culture which shapes the intelligence system. Persisting ideas can come to form part of a national culture that ultimately shapes the actors, interests, and decision-making of intelligence stakeholders. This thesis illuminates how specific American cultural symbols influence and reflect U.S. intelligence ideas, discourses, policies, and practices, thereby contributing to a distinctly “U.S. intelligence culture.” As a result, this dissertation demonstrates that national cultural symbols are not epiphenomenal: These symbols tangibly influence the thought and action of diverse audiences both within and outside the formal U.S. intelligence community. Through an analysis of national and institutional definitions, norms, narratives, and warrants, the contours of a uniquely American intelligence culture emerge. A test case of how Pearl Harbor functions as a powerful cultural symbol among intelligence discourse communities illustrates national culture’s influence vis-à-vis policy decisions, intelligence reform, institutional openness, and intelligence education. Ultimately, this dissertation’s meta-theoretical lens and multi-perspective approach productively bring together conceptual resources from the fields of Intelligence Studies, Strategic Studies, and International Relations contributing to the development of “intelligence culture” as a theoretically sound and useful approach to studying intelligence-related phenomena.


title: Observation of Singly Charged Barium Ions in a Buffer Gas:  Towards a Functional Barium-Tagging System for Use in the Enriched Xenon Observatory

abstract: The observation of the rare neutrinoless-double-beta-decay will have major implications for both neutrino physics and particle physics on a whole. A positive observation will confirm the Majorana nature of the neutrino and demonstrate that lepton number is not strictly conserved. Furthermore, a measurement of the decay half-life will lend itself to a measurement of the absolute mass scale of the neutrino. The sensitivity to observing the neutrinoless-double-beta-decay of 136Xe is analyzed for the EXO experiment and the benefits of inclusion of a barium-tagging system in a future tonne-scale detector are demonstrated. Additionally, the sensitivity to single barium ion identification is analyzed for two different methods of observation – continuous excitation and intermodulation. The intermodulation technique was determined to be more sensitive as single barium ions were observed with a high signal-to-noise ratio of ~4 for a one second observation time. Single ions were not observed using the continuous excitation technique.


title: Self-Reference Elicits Slower Recall for Personality Congruent Adjectives: An Item-Specific Processing Effect

abstract: The fact that people remember more personality trait adjectives in a memory test after making self-reference judgments, relative to other types of judgments (e.g., other-reference and semantics), has been attributed to greater elaborative (i.e., item-specific) and organizational (i.e., relational) processing. The present research asked whether personality self-concept renders more item-specific processing when the self-referenced materials are personality congruent. Previous attempts to address this question were equivocal, as brief recall tests were used and amount recalled was the indicator of item-specific processing. Research shows that item-specific processing produces slower recall than does relational processing, whereas the latter protects against item loss on a second recall test. The present studies therefore tracked recall across two consecutive tests. Results demonstrated an uncrossed double dissociation in self-reference recall speed, wherein self-reported orderliness was associated with slower recall only when the adjectives described orderliness (Study 1; N = 98), and self-reported openness was associated with slower recall only when the adjectives described openness (Study 2; N = 92). In Study 3 (N = 163), participants who viewed their friend as highly orderly recalled orderliness adjectives encoded in an other-reference task more slowly, indicating that tapping the self-concept was not necessary to observe the association. However, the openness-recall speed relationship of Study 2 failed to replicate. In all studies, item loss was not related to personality or recall speed, suggesting relational processing differences were not responsible for the findings. Likewise, demand characteristics were likely not responsible either because personality measures in Study 2 were taken during mass testing. Recall speed was not associated with an indirect personality measure (i.e., Implicit Association Test), suggesting item-specific information was propositional, not associative. Theoretical considerations were centered on whether item-specific information rendered multiple memory traces, which is consistent with the slowing of recall predicted by a random search model of memory and cue-overload theory. Overall, convergent validity was fairly weak and predictive validity was poor, but methodological issues were identified and statistical refinements were suggested. The present studies nevertheless successfully linked individual differences in personality as represented in memory to the item-specific processing that occurred during self- and other-reference encoding.


title: The effect of male-male fight observation on female choice and offspring quality in Gryllus assimilis

abstract: Theory suggests that behaviours previously thought only to play a role in intrasexual selection can also be co-opted to serve in as honest indicators of male quality. In Gryllus assimilis, males fight more aggressively in front of a female audience; their elevated aggression may serve as a mate attraction signal. I investigated how observing a fight influenced various measures of reproductive success. I had two treatments: (1) females observed a fight between two males or (2) females observed two non-interacting males. I then assessed female preference using dichotomous and no-choice tests. After mating, I allowed females to lay eggs and raised a subset their offspring to adulthood. Females were more likely to mount dominant males, regardless of whether they had watched the fight, but dominant males did not have increased fecundity, viability, or offspring size. Audience effects in this species may not have evolved due to eavesdropping.


title: Extra-Cardiac Interference in Myocardial Perfusion Imaging with Rubidium-82 and Positron Emission Tomography

abstract: Interpretation of myocardial perfusion images, produced with blood flow tracer rubidium-82 chloride (82Rb) and positron emission tomography (PET), can be affected when high tracer uptake in extra-cardiac organs adjacent to the heart (stomach) interferes with the myocardium. Since extra-cardiac organs are physically spatially distinct from the myocardium, extra-cardiac interference (ECI) in 82Rb PET images arises from limited spatial resolution, and cardiac and respiratory motion. This thesis aims to provide automated methods that detect and correct ECI. Three algorithms were developed to fulfill these aims: the first detects and ranks severity of ECI, the second attempts ECI correction based on factor analysis of dynamic image series, and the third corrects ECI with a 1D convolution-based method. All algorithms were developed, implemented and evaluated based on sets of clinical images. The detection and severity classification (DSC) algorithm was developed based on concordance of a 200 image dataset with clinical interpretation. It detected ECI with high accuracy (97% sensitivity and 82% specificity), low failure rate (<1%) and short execution time (<7s). The algorithm was used to estimate prevalence of ECI in a 4920- image dataset and to determine if simple modifications to image processing protocols could reduce ECI prevalence and/or severity. While reduced filtering showed the most promise, none of the available modifications eliminated ECI in the majority of images. Factor analysis of dynamic image series uses differences in the temporal behaviour of tracer uptake in the myocardium compared to that in the extra-cardiac organ to separate the two structures. Variations of this approach, applied to 82Rb PET images, were not able to simultaneously correct images with ECI of all severities and avoid reducing myocardial intensity in images without interference prior to correction. The 1D convolution-based correction algorithm modeled the image point spread function, including the effects of motion, as a 1D Gaussian and the underlying myocardial and stomach tracer uptake as simple 1D rectangular functions. This algorithm corrected images with ECI of all severities without reducing myocardial intensity in ECI-free images and >90% of scans examined showed visually acceptable correction. The convolution-based correction algorithm shows promise as a softwarebased ECI correction.