VictorJuiz/thesis huggingface dataset:
Changeable and Privacy Preserving Face Recognition

Traditional methods of identity recognition are based on the knowledge of a password or a PIN, or possession factors such as tokens and ID cards. Such strategies usually afford low level of security, and can not meet the requirements of applications with high security demands. Biometrics refer to the technology of recognizing or validating the identity of an individual based on his/her physiological and/or behavioral characteristics. It is superior to conventional methods in both security and convenience since biometric traits can not be lost, forgotten, or stolen as easily, and it is relatively difficult to circumvent. However, although biometrics based solutions provide various advantages, there exist some inherent concerns of the technology. In the first place, biometrics can not be easily changed or reissued if compromised due to the limited number of biometric traits that humans possess. Secondly, since biometric data reflect the user's physiological or behavioral characteristics, privacy issues arise if the stored biometric templates are obtained by an adversary. To that end, changeability and privacy protection of biometric templates are two important issues that need to be addressed for widespread deployment of biometric technology. This dissertation systematically investigates random transformation based methods for addressing the challenging problems of changeability and privacy protection in biometrics enabled recognition systems. A random projection based approach is first introduced. We present a detailed mathematical analysis on the similarity and privacy preserving properties of random projection, and introduce a vector translation technique to achieve strong changeability. To further enhance privacy protection as well as to improve the recognition accuracy, a sorted index number (SIN) approach is proposed such that only the index numbers of the sorted feature vectors are stored as templates. The SIN framework is then evaluated in conjunction with random additive transform, random multiplicative transform, and random projection, for producing reissuable and privacy preserving biometric templates. The feasibility of the introduced solutions is well supported by detailed theoretical analyses. Extensive experimentation on a face based biometric recognition problem demonstrates the effectiveness of the proposed methods.

Keywords: Biometrics
Changeability
Dimensionality reduction
Face recognition
Privacy
Random transformation
Template protection
Advisor: Hatzinakos, Dimitrios
Stationary Waves in the Stratosphere-troposphere Circulation

Stationary wave theory elucidates the dynamics of the time mean zonally asymmetric component of the atmospheric circulation and separates it from the dynamics of the zonal mean climatological flow. This thesis focuses on the dynamics of stationary wave nonlinearity and its applications in stationary wave modelling and the stationary wave response to climate change. Stationary wave nonlinearity describes the self-interaction of stationary waves and is important in maintaining the observed zonally asymmetric atmospheric general circulation. Stationary wave nonlinearity is examined in quasi-geostrophic barotropic dynamics in both the presence and absence of transient waves. Stationary wave nonlinearity is shown to account for most of the difference between the linear and full nonlinear stationary waves, particularly if the zonal-mean flow adjustment to the stationary waves is taken into account. Wave activity analysis shows that stationary wave nonlinearity in this setting is associated with Rossby wave critical layer reflection. A time-integration type nonlinear stationary wave modelling technique is tested in this simple barotropic setting and is shown to be able to predict stationary wave nonlinearity and capture the basic features of the full nonlinear stationary wave. A baroclinic nonlinear stationary wave model is then developed using this technique and is applied to the problem of the stationary wave response to climate change. Previous stationary wave modelling has largely focused on the tropospheric circulation, but the stationary wave field extends into the stratosphere and plays an important dynamical role there. This stationary wave model is able to represent the stratospheric stationary wave field and is used to analyze the Northern Hemisphere stationary wave response to climate change simulated by the Canadian Middle Atmosphere Model (CMAM). In the CMAM simulation changes to the zonal mean basic state alone can explain much of the stationary wave response, which is largely controlled by changes of the zonal mean circulation in the Northern Hemisphere subtropical upper troposphere. However, details of the stratospheric wave driving response are also sensitive to other aspects of the zonal-mean response and to the heating response. Many climate change related effects appear to contribute robustly to an increased wave activity flux into the stratosphere.

Keywords: stationary wave
stationary wave modelling
general circulation
Rossby wave dynamics
stratospheric circulation
critical layer reflection
coupled chemistry model
Advisor: Kushner, Paul
Three Dimensional Radio Frequency Current Density Imaging

Biological tissues are generally conductive and knowing the current distribution in these tissues is of great importance in many biomedical applications. Radio frequency current density imaging (RF-CDI) is a technology that measures current density distributions at the Larmor frequency utilizing magnetic resonance imaging (MRI). RF-CDI computes the applied current density, J, from the non-invasively measured magnetic field, H, produced by J. The previously implemented RF-CDI techniques could only image a single slice at a time. The previous method for RF current density reconstruction only computed one component of J. Moreover, this reconstruction required an assumption about H, which may be easily violated. These technical constraints have limited the potential biomedical applications of RF-CDI. In this thesis, we address the limitations of RF-CDI mentioned above. First, we implement a multi-slice RF-CDI sequence with a clinical MRI system and characterize its sensitivity to MRI random noise. Second, we present a novel method to fully reconstruct all three components of J without relying on any assumption of H. The central idea of our approach is to rotate the sample by 180 degrees in the horizontal plane to collect adequate MR data from two opposite sample orientations to compute one component of J. Furthermore, this approach can be extended to reconstruct the other two components of J by adding one additional sample orientation in the horizontal plane. This method has been verified by simulations and electrolytic phantom experiments. We have therefore demonstrated for the first time the feasibility of imaging the magnitude and phase of all components of the RF current density vector. The work presented in this thesis is expected to significantly enhance RF-CDI to image biological subjects. The current density vector J or any component of J can be measured over multiple slices without the compromise of motions of organs and tissues caused by gravitational force, thanks to the method of horizontal rotations. In addition, the reconstruction of the complex conductivity of biological tissues becomes possible due to the current advance in RF-CDI presented here.

Keywords: Magnetic Resonance Imaging (MRI)
Current Density Imaging (CDI)
Radio Frequency CDI
Advisor: Joy, Michael
Nachman, Adrian
The Integration of Language and Content: Form-focused Instruction in a Content-based Language Program

Content-based language instruction has gained widespread acceptance as an effective approach in a range of educational settings for adults and children. It is premised on the belief that language and content are inextricably linked and that learning is enhanced through an integrated approach. Yet the nature of the relationship between content and language, and how integration can be achieved in the content-based language classroom, continue to be points of divergence for both researchers and practitioners. One approach to this question draws on research in form-focused instruction (FFI), which describes various instructional options that draw learners’ attention to form in primarily meaning and content-based classrooms. While widely accepted that FFI has a positive impact on language learning outcomes in a variety of contexts, FFI research in content-based language programs for adults has been limited. This study investigated the effect and effectiveness of FFI in a content-based language program designed to prepare adult newcomers to Canada for employment in a specific workplace sector. Two groups of adult learners participated in the study. One group of 16 adults received content-based instruction integrated with FFI while the other group of 20 adults received the same content-based instruction with a focus on meaning only. A quasi-experimental, pre-test/post-test/delayed post-test design was adopted for this comparative study in order to measure language and content outcomes. Language measures included an error correction task, a cloze task, and oral production tasks. Content outcomes were measured via content tests. In addition, a retrospective awareness protocol was designed to assess learners’ awareness of language and content in their instruction and to explore the relationship between this awareness and language development. ANOVA and ANCOVA results indicated that there was no advantage for the participants receiving form-focused instruction on language outcomes but a significant benefit on the content knowledge tests. Analysis of the retrospective report data indicated that the participants were able to identify the focus of the instruction they received. However, no relationship between awareness of language and language development was found. These findings are discussed in light of previous research and in terms of their implications for content-based language instruction.

Keywords: Form-focused instruction
Content-based language teaching
grammar instruction
meaning-based language teaching
professional language teaching
vocational language teaching
English for Specific Purposes
language awareness
form-focussed instruction
meaning-focussed language instruction
occupational language
Advisor: Spada, Nina
Symptomatology, Stress Responses and Coping Resources in School-age Romanian Adoptees

The objective of this study was to examine symptomatology; stress responses for everyday academic and social stressors; and cognitive coping resources among 11-year-old children adopted from Romanian orphanages. Two groups were established by the amount of time spent within the institutional system. Early adoptees (EAs, n=25) spent less than 6 months while late adoptees (LAs, n=14) endured 6 months or more of institutionalization. A comparison group of non adopted, same-age peers (Canadian Born (CBs), n=25) was included. The first goal was to investigate whether there were differences between EAs and LAs in ratings of symptomatology and stress responses. The second goal was to compare all Romanian adoptees (RAs) to CBs on the same set of factors. The third goal was to identify predictors of symptomatology and predictors of stress responses for RAs only. The main findings were as follows. EAs and LAs did not differ in any symptom ratings or stress responses, showing a lack of evidence for duration of deprivation as a grouping factor. Significant differences were detected by adoption status. Ratings were higher for RAs than CBs in parent-rated symptomatology, including the rate of RAs who exceeded the borderline clinical cut-off. RAs reported less secondary control coping for social stressors than CBs. Models to predict symptoms from stress responses were not supported, with one exception. More disengagement coping for social stress and less involuntary disengagement for academic stress predicted less externalizing and generalized symptoms by teacher report. Models to predict stress responses from cognitive coping resources were significant except for disengagement coping. One of the main findings was that predictors of secondary control coping varied by stressor domain. In conclusion, the findings were important in demonstrating that duration of deprivation does not differentiate between post-institutionalized preadolescents in aspects of psychosocial adjustment. Adoption status is a significant factor. Stress responses do not contribute to models of symptoms. The cognitive coping resources of perceived academic competency and social-support contribute to models of stress responses, yet with room to improve the predictive power of the models. Implications of the findings are discussed along with limitations and directions for future research.

Keywords: Romanian
School-age children
Stress responses
Symptomatology
Post-institutionalized
Adopted
Advisor: Manassis, Katharina
The Influence of Perceived Fairness and Relational Leadership on Nursing Safety Climate and Work Environment

Canadian statistics on patient safety in acute care hospitals are alarming. Hospital safety concerns are not isolated to patient safety. Occupational safety is also important. With increasing shortages of nurses, stress in the work place is growing. Nurses report high levels of absenteeism of 14.5 days per year. The importance of a just and fair culture and the role of nurse leaders have been emphasized in safety literature. Although deemed important, studies of nurse leaders and patient outcomes are limited. The influence of interactional justice in the workplace on nurse and patient safety has not been studied. The purpose of this study was to test and refine a model developed from the literature which explains the impact of perceived interactional justice, relational leadership, and quality of nurse manager – clinical nurse relationships on the nursing work environment and ultimately patient and nurse safety outcomes. The model was tested on a random sample of 266 Ontario acute care registered nurses. Findings indicated the model reasonably fit the observed data, however could benefit from further refinement. The addition of 2 pathways (span of control to nurses’ intent to leave and number of medication errors to nurse emotional exhaustion) and trimming of the insignificant paths improved the overall model fit. The resulting model indicates that resonant leadership style and interactional justice improves the quality of nurse leader-nurse relationships which in turn improves quality of the nurses’ work environment and safety climate. A positive safety climate led to a decrease in the number medication errors and nurses’ intentions to leave their unit. A higher quality work environment predicted lower nurse emotional exhaustion. Additionally, higher numbers of medication errors led to an increase in nurse emotional exhaustion. This suggests that distress may be associated with making a medication error or fear of consequences. As well, larger manager spans were associated with less nurse intent to leave. As the span increased, the number of support personnel also increased. Contrary to other research findings, this result suggests that supportive personnel may mitigate the effect of large manager spans of control on nurses’ intent to leave their units.

Keywords: safety climate
nursing
work environment
relational leadership
interactional justice
emotional exhaustion
medication errors
intent to leave
Advisor: Tourangeau, Ann
Can the Assembly of First Nations Education Action Plan Succeed? Colonialism’s Effect on Traditional Knowledge in Two Communities.

have altered the context and practices of the First Nations culture and by so doing, compromised their will and capacity to implement traditional education policies, a situation that must be linked to realization of the Education Action Plan’s goals. The goal of the study was to assist policy makers, community leaders, and educators in recognizing the attitudes, social norms, and practices that are interwoven with post-colonial trust issues at the community level and to focus on the viability of preservation of First Nations heritage and culture. The inquiry documented and analyzed, in a case study approach, the dynamics of colonialism on two First Nations communities. Interviews and questionnaires, utilized in communities, were based on a matrix that directed comments to areas associated with traditional knowledge, remnants of colonialism and areas of will and capacity. The focus of the inquires referred to curriculum content, funding, school and community structure, as well as traditional knowledge, communication, participation, and the role of members in shaping the community values and school curricula. In all, 32 people were formally interviewed including teachers, Elders, education council members, principals, and community leaders. The study comprised 14 interviews and 17 questionnaires in Two Rivers, and 18 interviews and 8 questionnaires in Round Rock. The study intended to establish whether colonialism would play out in the implementation of the traditional knowledge aspect of the Education Action Plan and if so, in what areas and in what manner. Through research, it was

Keywords: First Nations
First Nations Communities
First Nations Schools
First Nations Communitiy Curriculum
Traditional Knowledge
Traditional Knowledge and Colonialism
Colinialism and First Nations
Colonialism and Curriculum in First Nations Schools
Advisor: Bascia, Nina
Regulatory Effects of the Actin-binding Proteins Moesin and MyosinII on Synaptic Activity at the Drosophila Neuromuscular Junction

The nervous system is made up of specialized cells which receive and respond to environmental stimuli. Intercellular communication in the nervous system is achieved predominantly through chemical synaptic transmission. Within the chemical synapse, the actin cytoskeleton plays a major role in regulating synaptic activities, although the extent and clarity in our understanding of these processes is still limited. Using the genetically pliable model, Drosophila melanogaster, this thesis begins to unravel contributions of actin binding proteins to synaptic development and physiology at the larval neuromuscular junction (NMJ). Two actin binding proteins, Moesin and Nonmuscle Myosin II (NMMII) were selected for study based on previous studies implicating them in synaptic development. Combining genetics, fluorescent imaging and electrophysiological recordings this thesis unveils previously unidentified functions for Moesin and NMMII in morphology and physiology of the Drosophila NMJ. Moesin was found to help restrain synaptic growth but did not affect synaptic physiology. By correlating morphological and electrophysiological measurements in Moesin mutants, it was determined that physiology and morphology can be independently regulated at the NMJ. NMMII was used to investigate a role for actin binding proteins in physiology at the Drosophila NMJ. By using the fluorescent imaging technique, FRAP, this becomes the first research to implicate NMMII in unstimulated synaptic vesicle mobility. FRAP indicated that vesicle mobility was highly dependent on the expression level of NMMII. Electrophysiological analysis of NMMII indicated distinct mechanisms for spontaneous and evoked vesicle release. NMMII expression exhibited a positive correlation with basal synaptic transmission and was important in mobilizing vesicles for synaptic potentiation. In addition, NMMII was found to be involved in a high frequency dependent low frequency depression. This work begins to identify how vesicles traverse within boutons and suggests differential mechanisms of synaptic release, both of which are partially dependent of NMMII expression. Studying Moesin and NMMII have revealed a complex interplay between the actin cytoskeleton and synaptic function and together this research furthers our understanding of how the actin cytoskeleton regulates synaptic activity.

Keywords: Drosophila
neuroscience
Moesin
Myosin
neuromuscular junction
physiology
neuron
synaptic transmission
potentiation
high frequency
N-ethylmaleimide sensitive factor
morphology
FRAP
electrophysiology
vesicle
low frequency depression
development
actin
cytoskeleton
growth
neural
nervous
Advisor: Stewart, Bryan
Characterization of the Motion and Mixing of Droplets in Electrowetting on Dielectric Devices

The physical mechanism responsible for droplet manipulation in electrowetting on dielectric (EWOD) devices is not yet fully understood. This investigation will examine the role of capillary forces on droplet manipulation to further the physical understanding of these devices. An analytical model for the capillary force acting on a confined droplet at equilibrium is developed here. Model predictions were validated using optical measurements of the droplet interface in the vertical plane. It was found that the capillary force and interface shape predicted by the equilibrium model were over an order of magnitude more accurate than predictions from the model commonly used in EWOD investigations. The equilibrium model was adapted to droplets with arbitrary shapes to predict droplet dynamics in EWOD devices. It was found that droplet motion could be described using the driving capillary force and frictional forces from wall shear, the contact line, and contact angle hysteresis. Comparison with experimental data shows that this model accurately predicts the effects of applied voltage and droplet aspect ratio on the transient position and velocity of droplets. This model can be used to design EWOD devices and predict the simultaneous manipulation of droplets required to meet the high throughput demands of practical applications. A robust system for droplet monitoring must be automated before EWOD devices can be used reliably in practical applications. Although capacitance measurements have been used to automate droplet detection in EWOD devices, manual optical measurements are generally used to monitor droplet mixing. This may not be possible in high throughput applications with multiple droplets and limited optical access. Here, capacitance measurements are shown to be an accurate and repeatable means of monitoring droplet composition and real time mixing. Experiments were performed with this technique to show that mixing efficiency is better characterized by the number of translations required for full mixing, not mixing time.

Keywords: Electrowetting
Microfluidics
Advisor: Mrad, Ridha Ben
Sullivan, Pierre E.