14277 research outputs found
Sort by
Assessing climate change impacts on hydrology and agriculture in a boreal watershed: a combined hydrological modeling, machine learning, and efficiency analysis
No full textClimate change poses significant challenges to water resources and agriculture sustainability, particularly in boreal watersheds. Understanding hydrological dynamics and their response to climate variability is essential for effective water management and sustainable farming practices. This dissertation uses various models and a transdisciplinary approach to investigate the hydrological dynamics, climate change impacts, and agricultural sustainability in the Upper Humber River Watershed (UHRW) of western Newfoundland, Canada. Using the soil and water assessment tool (SWAT) model, the study evaluates watershed hydrology and identifies key parameters influencing streamflow, achieving favorable performance metrics during calibration and evaluation. Seasonal and monthly flow patterns, water balance components, and flow duration analyses validate the model's suitability for sustainable water management. Similarly, a Long Short-Term Memory (LSTM) machine learning model was developed for UHRW. The comparative analysis of the SWAT and LSTM models for streamflow prediction highlights the superior accuracy in capturing streamflow prediction. The LSTM model’s integration of real-time data demonstrates its potential for effective water management in cold climates. Furthermore, this dissertation explores climate change impacts on soil water availability (SWA) in UHRW using Coupled Model Intercomparison Project Phase 5 (CMIP5) projections and Representative Concentration Pathways (RCP) scenarios. Results reveal up to an 11% decline in SWA under RCP 8.5, driven by increased evapotranspiration and streamflow, despite rising precipitation. Lastly, agricultural sustainability is assessed through Data Envelopment Analysis (DEA), identifying high technical efficiency yet notable disparities in allocative, cost, scale, and environmental efficiencies. Sustainable practices, such as permaculture, no-dig farming, and resource optimization, enhance productivity while minimizing environmental impacts. This dissertation offers insights for water management, climate adaptation, and sustainable farming in boreal ecosystems
Enhanced methods for surface current estimation from X-band radar data
No full textEstimating ocean surface currents accurately is crucial for a wide range of applications,
including marine navigation, environmental monitoring, and coastal management. Traditional
methods for measuring surface currents face challenges such as limited spatial coverage
and sensitivity to environmental noise, making the development of more accurate and robust
techniques a pressing need in oceanography. This thesis focuses on improving the accuracy
and robustness of ocean surface current estimation using X-band radar image sequences by
introducing two novel algorithms.
In the first part of this thesis, a Symmetry of Doppler Shifts (SDS) method is introduced
for retrieving surface current information from radar images. The method focuses
on extracting the wave angular frequencies and corresponding wavenumbers from the radar
image sequences. Then, Doppler shifts are calculated based on wavevectors that exhibit
symmetry with respect to the origin in the wavenumber plane. These Doppler shifts are
used to estimate both the speed and direction of surface currents. Simulations with synthetic
data show that the SDS method achieves a root mean square error (RMSE) of 0.13
m/s for current speed and 1.4° for direction. The results indicate that the method performs
with accuracy comparable to existing techniques under simulated conditions.
The second part of this research builds on the SDS method by integrating it with an
enhanced Polar Current Shell (PCS) algorithm. The improvements include the application of
Kernel Density Estimation (KDE) for noise filtering, interquartile range filtering to remove
outliers, and symmetry-based noise reduction. The modified PCS method also employs
a single curve-fitting process, analyzing all wavenumbers in the PCS domain collectively
rather than individually. The improved algorithm was validated with both simulated data
and real-world radar data from a Decca radar (2008) and a Koden radar (2017). Results
show that the modified PCS method reduces the RMSE for speed by 0.06 m/s and direction
by 3.8° for the Decca radar, and by 0.02 m/s for speed and 4.6° for direction for the Koden
radar, compared to the original PCS method.Includes bibliographical references (pages 71-78
Evaluating the performance of ocean gliders’ technology to characterize ship-radiated underwater noise
No full textThis study uses passive acoustic monitoring techniques to investigate the potential
of Autonomous Underwater Gliders for assessing and localizing a controlled vessel
through underwater radiated noise. The propagation of noise was investigated through
an advanced propagation loss model utilizing oceanography data collected by the
glider. Comprehensive sea trials were conducted using a Slocum G3 glider equipped
with acoustic capabilities. These trials involved capturing the underwater radiated
noise from a specific vessel while simultaneously collecting oceanographic data. The
first step involved identifying the noise pattern of the target vessel and assessing the
individual noise sources in accordance with ISO standards. Subsequent trials involved
using a glider, a hydrophone array, and a seabed-moored hydrophone to further analyze vessel noise signatures. The acoustic performance of the glider was compared to
that of other conventional stationary platforms. A study was conducted to evaluate
the self-noise produced by the glider in order to ensure the precision of the acoustic
data. Furthermore, sound propagation loss was studied using the gathered oceanic
data. Propagation loss models were developed in two distinct environmental conditions: 1) a shallow coastal inlet 80 m deep and 2) a deep bay up to 200 m deep during
summer and winter, both in the presence and absence of strong surface stratification. A range- and depth-dependent sound speed profile map was created to estimate
propagation loss inside the area covered by the glider. This led to the testing and
improvement of advanced sound propagation models compared to the ISO standard
17208 formulations. The findings demonstrate that the gliders can characterize and
measure ship-based URN and locate the direction of the source relative to the glider,
thereby improving the understanding of the spatial and temporal variability of ocean
sound sources. The study supports the use of AUGs in marine acoustic monitoring, which has implications for environmental policies and the development of quieter
vessels.Includes bibliographical references (pages 138-158
History and myth in genres of crisis: a comparative study of Hollywood Westerns and Chinese wuxia films
No full textAs iconic forms of popular culture in their respective countries, Hollywood Westerns and Chinese wuxia films serve not only as vehicles of international cultural exchange but, more significantly, as powerful mythmaking tools that shape and transmit historical memory and national mythologies, offering idealized or contested visions of the nation’s past. While existing scholarship has delved into the historical development, symbolism, and cinematic techniques of each genre individually, systematic comparative studies that explore their underlying ideologies in relation to their distinct national contexts remain limited. In response, this dissertation offers a detailed cultural-historical comparative study of the American Western and Chinese wuxia film genres. It approaches this comparison through three prominent directions of contemporary critical inquiry—frontier narrative and ethnic representation, gender formation, and the aesthetics of nature—while deliberately selecting underexplored perspectives within these broader categories. Specifically, it examines how Westerns and wuxia films represent their respective western frontier, ethnic minorities, gendered ideals of heroic violence, and aestheticized natural landscapes, to reveal the convergences and divergences between American and Chinese worldviews and their underlying conceptions of ethnicity, gender, and nature as expressed through these cinematic portrayals.
While striving to provide an overview of how both genres have evolved in their representations across these dimensions, this dissertation maintains a focused analysis of key works produced during the mature stages of the two film genres. The selection of American
Westerns spans from the postwar period to the 2000s, encompassing both classic films from the genre’s golden age and representative works from the revisionist movement. The selection of wuxia films covers three pivotal phases in the genre’s development: the golden age of Shaw Brothers’ productions in the 1960s and 1970s, the rise of Hong Kong–mainland China coproductions in the 1980s and 1990s, and the emergence of globally influential transnational wuxia films in the 2000s. By situating Hollywood Westerns and Chinese wuxia films within their respective sociopolitical contexts and cinematic-cultural traditions from the post–World War II era to the early 2000s, this comparative study foregrounds genre as a dynamic cultural form—one that negotiates shifting ideologies of identity, memory, and belonging rather than reaffirming fixed civilizational binaries.
This dissertation bridges a gap in cross-cultural genre studies and expands the scope of comparative film research, fostering intercultural awareness and encouraging critical reflection on the cultural narratives and assumptions that shape both cinematic traditions
The Café Concert Project: music programming for student engagement at Memorial University
No full textWith a deep respect for the student voice, this study explores the Café Concert Project, a music-based initiative designed to enhance student engagement and foster a sense of belonging within the university community. Situated within Canadian student affairs, the research examines how music programming can create meaningful connections and support students' emotional and social integration into university life. This study highlights the critical role of belonging and community in enhancing engagement outcomes by centring the student voice through collaborative autoethnography.
Grounded in student development theories that emphasise student involvement and the significance of social integration in student retention and informed by the practices of leading music-in-community researchers, this project investigates how music-making on campus bridges student affairs and community-building. Using individual narratives and a collective social lens, the study employs collaborative autoethnography as data to capture both personal and shared experiences.
Through examining student experiences in the Café Concert, this research provides valuable insights into how arts-based engagement initiatives can actively foster a sense of belonging and build inclusive communities on campus. The findings suggest that music-making strengthens students' social connectedness by creating shared experiences and serves as a meaningful support system that enhances their university journey. By creating a space where students feel connected and valued, the Café Concert Project demonstrates the potential of music programming to positively impact students' academic and personal lives, reinforcing their integration within the university's social fabric
One loop calculations of rare -decays beyond the standard model
No full textRare -meson decays provide a sensitive window into potential physics beyond the
Standard Model (SM), as they occur only through loop-level processes and are heavily
suppressed by the Glashow-Iliopoulos-Maiani (GIM) mechanism. These suppressed
transitions, such as the → processes, are particularly useful in the investigation of
new particles that may contribute through virtual effects. One compelling possibility
is the existence of vector-like quarks (VLQs), which can mix with Standard Model
quarks and modify flavor-changing neutral current (FCNC) processes.
VLQs, being singlets under the electroweak symmetry and not requiring symmetry
breaking for mass generation, can be much heavier than SM quarks. Although difficult
to detect directly at colliders, their effects may be observed indirectly through precise
measurements in rare decays. In this work, we explore the influence of down-type
iso-singlet VLQs on rare decays, focusing on decay ⁺ → ⁺̄, which is both
theoretically clean and sensitive to new physics. Recent results from the Belle-II
collaboration report a branching ratio of [2.3 ± 0.5 (stat)] × 10⁻⁵ [43], which provides
evidence at the 2.7σ level and lies significantly above the Standard Model prediction
of [0.45±0.7]×10⁻⁵ [72]. This discrepancy motivates the study of VLQ contributions
to this process.
To constrain the new physics parameter ₛᵦ, we also examine related decays such
as ₛ → μ⁺μ⁻ and → ₛμ⁺μ⁻. Using these constraints, we compute modified
Wilson coefficients (C₇, C₉, C₁₀ and CL) within an effective field theory framework,
incorporating VLQ contributions. These coefficients are then used to calculate the branching ratios for → ₛ̄ and → ̄.
Our analysis shows that the inclusion of VLQs can significantly enhance these
branching ratios. The resulting parameter space, illustrated by ᵪ² contour plots,
highlights VLQs as a viable and testable candidate to explain anomalies in rare
-meson decays
Design of efficient power converters for electric vehicle charging and vehicle-to-grid applications
No full textThis research presents the design and optimization of bidirectional Dual Active Bridge
(DAB) convertersfor electric vehicle battery charging applications, encompassing both
heavy and light electric vehicles. The core of the studies is a 5.6 kW DAB converter
that can seamlessly transition between 3.7 kW and 11.2 kW power outputs to
accommodate different vehicle requirements without the need for circuit component
changes. This flexibility is achieved through the novel integration of interleaved and
parallel operation capabilities, allowing for efficient operation across a broad power
range.
Key innovations include the design of a high-frequency transformer with dual
secondary outputs to facilitate power transfer at high currents up to 30 A, optimizing
thermal design and minimizing the stress on the circuit board. The use of next�generation power semiconductors and low-loss magnetic circuit elements has resulted
in an optimized single-stage bidirectional converter design that showcases enhanced
efficiency and competitiveness in the field. Furthermore, the converters design enables
easy reconfiguration to meet the desired power output, vehicle type, and application
needs, making it adaptable for future applications such as Vehicle-to-Grid (V2G)
systems.
The combination of these features, versatility in power output, efficient high-current
transfer, innovative use of power semiconductors, and adaptability for future
technologies—positions this DAB converter as a significant advancement in electric
vehicle charging technology, offering a scalable solution to meet the evolving demands
of electric mobility and renewable energy integration.Includes bibliographical references (pages 82-84
Building inclusive cities and mobility systems for immigrants in Atlantic Canada
No full textTraditionally, immigrant transit research in Canada has focused on the three largest census metropolitan areas (CMAs): Toronto, Montreal, and Vancouver (TMV). However, with the increase in immigration to small and mid-sized cities (SMCs), as seen in Atlantic Canada, the question of whether the transit systems in these SMCs will support the growing immigrant population remains. This question is particularly important as studies in large CMAs have shown that immigrants rely on public transit more than their Canadian-born counterparts. This thesis bridges the gap that exists in literature by examining immigrant transit experiences and policy responses in two mid-sized cities in Atlantic Canada: Halifax, Nova Scotia, and St. John’s Newfoundland and Labrador.
Combining policy analysis, 12 key-informant interviews, 267 online surveys, and 20 ride-along interviews, this research identifies the barriers immigrants face when interacting with the transit space in these Canadian SMCs and the policy responses from the municipalities. The findings underscore that immigrants have varied, unique experiences that impact how they interact with the transit system in their destination cities. Some of these include navigating the unfamiliar landscape, navigating transit systems in winter, the stigma associated with transit use and car-centric culture, and mobility experiences across borders. More specifically, this project explores how to incorporate immigrant needs into transit planning, highlighting the importance of partnerships and engagement, fostering a culture of transit use, and reflecting community diversity in transit operations and workforce. Since the transit systems in Atlantic provinces have long struggled with adequate riders to justify investment in transit, recognizing immigrants as guaranteed riders will play a key role in the transit system being a tool for immigrant inclusion and retention
Energy-Conscious and Regulation-Ready Security Protocol for Wearable Medical Devices: From Formal Proofs to Deployment
No full textPublishedThis paper introduces a formally verified, lightweight security protocol
tailored for energy-constrained wearable medical devices
operating in regulated healthcare environments. Designed to satisfy
emerging cybersecurity mandates from HIPAA, GDPR, and
Health Canada, the protocol incorporates Ed25519-based mutual authentication,
ephemeral Curve25519 key exchange, and ChaCha20-
Poly1305 authenticated encryption, providing in-transit protection
across heterogeneous nodes with minimal computational and energy
overhead. Formal verification through ProVerif and Scyther
confirms strong resilience against key compromise, replay, and
session confusion, with verified guarantees of end-to-end authentication,
forward secrecy, nonce protection, and key integrity across
multi-node interactions. To ensure practical feasibility, the protocol
was validated through a dual-phase evaluation strategy. A
Python-based simulation testbed enabled controlled symbolic testing,
adversarial fault injection, and modular verification of cryptographic
behavior and session dynamics. This was followed by
real-world deployment on an STM32L431-powered ECG wearable,
relayed through an Android node to a cloud server. Energy profiling
with Nordic PPK2 measured only 7.91mWh of daily security
overhead, under 16% of system budget, supporting 30+ days
of secure operation per charge. The total system consumption
( 58mWh/day) remains lower than many reported BLE-ECG designs
[1, 35] that lack full-stack security, demonstrating that strong
cryptographic guarantees can be achieved without exceeding typical
power budgets. These results affirm that regulatory-compliant,
secure communication is feasible in embedded MedTech systems
without compromising runtime efficiency, offering a reproducible
model for future IoMT protocol research and deployment
Overcoming limited field of view challenges in whole-body CT scans: a GAN approach for imputing truncated tissues
No full textOne of the significant challenges in medical imaging is the limited field of view
(FOV) in computed tomography (CT) scans, which often results in truncated tissues.
This limitation can hinder accurate diagnosis and affect subsequent medical decisions,
as it can lead to incorrect body composition (BC) measurements. While existing AI
methods for FOV extension have shown promise in recovering truncated parts, they
are limited to two-dimensional (2D) CT images. This thesis presents a two-stage
method for extending the FOV in whole-body three-dimensional (3D) CT scans to
address tissue truncation caused by limited FOV. In the first stage, a bounding box
predicts the full body extent, allowing the FOV to be symmetrically extended. The
second stage uses an image completion model (Recurrent Feature Reasoning Network
(RFR-Net)) to fill in the missing tissue in truncated regions. To effectively train the
model, we generated synthetic FOV truncation patterns from complete CT slices.
The method was rigorously evaluated by comparing BC metrics, such as skeletal
muscle and fat, before and after truncation correction. Our results demonstrate that
the model successfully restores missing anatomical structures and significantly reduces
errors in BC measurements. Specifically, the Mean Absolute Percentage Error
(MAPE) for skeletal muscle volume was reduced from 39.28% to 6.56%, for fat volume
from 44.55% to 7.35%, and for bone volume from 32.23% to 7.68%. Furthermore,
the pixel-wise hounsfield unit (HU) performance metrics showed promising results,
with an overall Structural Similarity Index (SSIM) of 0.9871. This approach offers
a practical solution for enhancing CT scan quality in cases of limited FOV, thereby
improving clinical assessments and diagnostics in medical imaging applications.Includes bibliographical references (pages 56-67)