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Glass Fiber-Reinforced Polymer (GFRP) Reinforced Concrete Corner Joints Subjected to Opening Moments
No full textConcrete corner joints are elements in structures that transfer forces between their adjoining members. In recent decades, glass fiber-reinforced polymer (GFRP) has been gaining popularity due to its corrosion resistance and light weight. However, its linear elastic properties and lack of practical bond slip theory make it challenging for engineers to properly detail GFRP reinforcement in corner joints. Previous studies on GFRP-reinforced concrete closing joints have been conducted at the University of Waterloo; however, no research has been conducted on GFRP-reinforced concrete opening joints.
The experimental program presented in this thesis consists of eight full scale corner joint specimens which were subjected to monotonic opening moments. The specimens are divided into two groups based on their tensile rebar geometry within the cantilever slab: Type A specimens with straight tensile bars, and Type B specimens with hooked tensile bars. Within each group, the specimens were constructed with one of the following: a) an unreinforced joint panel, b) bent bars perpendicular to the inner corner, c) confining stirrups within the joint panel, or d) both bent bars and confining stirrups. The aim of the study was to determine the effects of each design choice on corner joint behaviour.
Test results showed that increasing development length of GFRP using hooked bars reduced bond-slip and increased joint strength and deformability. When primary tensile cracks were constrained using bent bars or confining stirrups, the main influence of joint strength became the strength of the concrete. Joints that contained bent bars perpendicular to the inner corner exhibited more consistent post-peak responses and had higher joint deformability than their base specimens. Joints with confining stirrups saw reduced widths of shear cracks as well as reduced bond-slip of the bars they confined.
Further studies on GFRP-reinforced concrete joints must be conducted, including the study of the effect of different bent bar areas and sizes, different member geometries, as well as different GFRP development lengths/anchorage methods
Pre-treatment direct costs for people with tuberculosis during the COVID-19 pandemic in different healthcare settings in Bandung, Indonesia
No full text© 2025 Lestari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The tuberculosis (TB) program was massively disrupted due to the COVID-19 pandemic, which may have impacted on an increase in costs for people with TB (PWTB) and their households. We aimed to quantify the pre-treatment out-of-pocket costs and the factors associated with these costs from patients' perspective during the COVID-19 pandemic in Bandung, Indonesia. Adults with pulmonary TB were interviewed using a structured questionnaire for this cross-sectional study recruiting from 7 hospitals, 59 private practitioners, and 10 community health centers (CHCs) between July 2021 to February 2022. Costs in rupiah were converted into US dollars and presented as a median and interquartile range (IQR). Factors associated with costs were identified using quantile regression. A total of 252 participants were recruited. The median total pre-treatment cost was 54.51, IQR 29.48-98.47). The rapid antigen and PCR for SARS-CoV-2 emerged as additional medical costs among 26% of participants recruited in private hospitals. Visiting >-6 providers before diagnosis (26.20, p < 0.001), presenting first at a private hospital (34.97, p < 0.05), and being diagnosed in the private health sector (20.30, p < 0.05) were significantly associated with higher pre-treatment costs. PWTB experienced substantial out-of-pocket costs in the process of diagnosis during the COVID-19 pandemic despite free TB diagnosis and treatment. Early detection and identification play an important role in reducing pre-diagnostic TB costs.Bill & Melinda Gates Foundation, INV-022420
Understanding and Enforcing Precise Control in Generative Models via Graph‑Based Attention
No full textGenerative models have significantly advanced in recent years, enabling unprecedented capabilities for data generation, manipulation, and editing. However, their practical applicability depends heavily on their ability to disentangle the underlying factors of variation, allowing precise and controllable modifications. This thesis explores disentanglement from two complementary perspectives: latent-space disentanglement in Variational Autoencoders (VAEs) and spatial disentanglement in diffusion-based text-guided image editing.
In the first part of the thesis, we investigate the mechanisms behind disentanglement in VAEs. By proposing a local non-linear approximation of the VAE decoder, we provide a rigorous theoretical analysis that reveals orthogonality of the decoder's Jacobian as a fundamental condition for disentanglement. To support this finding, we introduce a quantitative measure termed the Orthogonality Deviation Score (OD-Score) and empirically demonstrate across multiple benchmark datasets (dSprites, 3D Faces, 3D Shapes, and MPI3D) that increased orthogonality directly corresponds to improved disentanglement as measured by established metrics such as Mutual Information Gap (MIG) and MIG-Sup.
In the second part, we address the challenge of spatial disentanglement in text-guided image editing using diffusion models. Traditional diffusion-based methods rely primarily on cross-attention maps derived from textual prompts to determine regions for editing, often resulting in unintended alterations and compromised spatial coherence. To overcome this, we introduce LOCATEdit, a novel approach that refines attention maps using a graph-based regularization framework. LOCATEdit constructs a Cross and Self-Attention (CASA) graph, leveraging patch relationships derived from self-attention to promote spatial consistency and to constrain edits precisely within designated areas. Extensive evaluations on the PIE-Bench dataset illustrate that LOCATEdit achieves superior performance in localized editing tasks, substantially outperforming existing baselines in both semantic alignment and background preservation.
Together, these contributions offer a unified understanding of disentanglement in generative modeling, bridging theoretical insights from latent-space analysis with practical advancements in spatially coherent, text-guided image editing. Ultimately, this thesis provides a principled foundation for developing interpretable, reliable, and highly controllable generative systems
Workload Balancing for Airline Flight Dispatchers
No full textWe study the flight dispatcher scheduling problem with the objective of balancing workload. Flight dispatchers are responsible for flight planning and monitoring, and their duties are characterized by multi-tasking and uncertainty.
We propose novel models, solution methods and a detailed analysis.
First, we introduce and analyze the flight dispatcher workload balancing problem. We model dispatcher workload under two objectives: minimizing peak workload and minimizing absolute workload deviation. To manage large problem sizes, we decompose the problem using Lagrangian relaxation into tractable subproblems and derive a closed-form expression for the Lagrangian lower bound of the peak workload objective. We then propose a focus-search-improve genetic algorithm, which integrates genetic search with refinement heuristics. Numerical tests on real-world flight data show that the heuristic finds optimal or near-optimal solutions and outperforms commercial solvers. It is found that minimizing peak workload reduces workload spikes while minimizing absolute deviation distributes workload uniformly.
Second, we incorporate practical and operational constraints such as route-based flight grouping and assignment restrictions based on flight characteristics. We provide a multi-objective model and propose three solution approaches, the weighted-sum method, the epsilon-constraint method, and the non-dominated sorting genetic algorithm II, to capture the trade-off between workload balance and operational efficiency. Computational experiments show that non-dominated sorting genetic algorithm II generates clear Pareto fronts and provides solutions that are comparable to those found by exact methods.
Third, we focus on the absolute deviation workload balancing problem which achieves balanced schedules but is computationally challenging. We propose a neural network-assisted column generation algorithm that predicts negative reduced cost solutions of the Lagrangian subproblems. Preliminary results demonstrate the viability of the approach in speeding up the column generation algorithm
A Woven Divide: Cotton, Property and Partition in the Indus River Basin
No full textIn less than a hundred years of colonial occupation, almost all of South Asia’s cotton species were erased. Where previously native communities had cultivated thousands of localized subspecies to foster unique properties, the British Empire imposed a single species of American cotton to meet their insatiable demand for textiles. My M.Arch research thesis examines cotton, in the context of South Asia, as a vessel for colonial extraction, environmental transformation, exploitation, and erasure. The displacement of Indigenous ‘desi’ cotton and propagation of ‘American’ cotton gave way to large scale environmental transformation, most notably the construction of the world’s largest irrigation system, to date, across the Indus River Basin. As the irrigation network transformed the province of Punjab into an agricultural asset, colonial intervention erased its forest, wetland and pastural landscapes. Simultaneously, colonial processes of extraction and manufacturing rendered native cotton methods obsolete, resulting in the degradation of textile tradition and the disappearance of native spaces of production such as kharkhanas.
With my research, I aim to create spatial documentation of cotton in undivided Punjab, from plant to fabric, as a means to explore how life in South Asia transformed through colonial processes. Through archival research, architectural documentation and tapestries, this thesis traces the processes of cotton cultivation and production across the Punjabi landscape from pre-colonial eighteenth century to British exodus in 1947. Specifically investigating the spatial operations executed by colonial forces in order to displace Indigenous methods of production, and the resistance which came as a response from native Punjabis. Through the obsolescence of these processes, native spaces of cultivation and production were changed forever, diminishing native people’s agency over their land, and altering the relationship between the built and ecological environment. By taking a multiscalar approach with every stage of cotton processing, this thesis disassembles the intertwined nature of imperial forces manifesting in scales from the river delta to the human body.
To expand beyond standardized drawing methods as a means of representation and challenge the epistemological truths upheld by these standards, I’m engaging with textile making in efforts to reconnect the work back to native practices and perspectives. The artifact crafted for this thesis was made by me as I uncovered knowledge of my grandmothers’ skills as textile artisans and connected their stories to the persistence of colonial forces in modern day nation-states which continue to diminish the agency and personhood of native communities in regards to land rights
Understanding the Dynamics of Human-Tiger Conflict in Chitwan National Park, Nepal
No full textThe forests of Chitwan National Park in the southern lowlands of Nepal provide habitat for more than 100 Bengal tigers. Recently, the tiger populations have increased in the region, which has increased the chances of conflict between tigers and people living in the vicinity of the park. In this study, the aim was to determine the dynamics of human-tiger conflicts and assess the perspectives of the local community towards tigers. Firstly, through desk research on human-tiger conflicts, the spatial and temporal variations of tiger attacks were assessed. Furthermore, clustering analysis was done to determine if the conflicts were uniformly distributed or not. Secondly, semi-structured interviews (n=54) were conducted with key informants and affected households across four municipalities of Chitwan district using targeted sampling. The results clearly revealed that there were hot spots of human-tiger conflicts, particularly concentrated in Bagai and Amaltari sectors. However, the presence of tigers was concentrated in the central core zone of the park. The findings from the interviews suggested that most of the tiger attacks are happening in the morning during collection of fodder in community forests, especially in a period between autumn and spring. The key informants (n=29) suggested that Madi, Meghauli and Kumroj are the areas more prone to attacks from ill and old tigers. The affected households (n=25) experienced tiger attacks within a kilometer from the core park boundaries. In general, people had a positive response towards tiger conservation, which could be attributed to the effective relief distribution scheme and public awareness. However, these affected households suggested that heavy dependency on forest resources compels them to visit community forests frequently despite the danger of the attacks. The coexistence between humans and tigers can be promoted by adopting conservation strategies such as ecotourism, which will uplift the livelihoods of the forest-dependent populations living along the boundaries of the park. Besides, timely identification and management of problem tigers is recommended, which may minimize the human-tiger conflicts
Dance/Movement Therapy for Dementia Caregiver Resilience: A Mixed-Methods Study
No full textAs Canada’s population continues to age, more individuals will be living with neurodegenerative conditions such as dementia and caring for loved ones with these conditions. The Government of Canada estimates that in 2022-2023, over 400,000 people were living with diagnosed dementia, and close to 99,000 were newly diagnosed that year (StatsCan, 2025). Most individuals living with dementia are taken care of by a family member (romantic partner/spouse or adult child). However, individuals who step in to take on this role often become burdened and distressed due to the grief associated with the losses their loved one is going through (relational, physical, cognitive) and the compounded strains of caregiving. Once dementia emerges and continues to progress, the negative impact on caregivers’ health and well-being is greater than on other caregiving groups (Kim & Schulz, 2008). Thus, it is imperative to explore how caregiver well-being can be maintained despite the ongoing losses with their loved one.
The majority of caregiver support programs which have been developed and evaluated are based on stress-process models, aiming to mitigate impacts of illness-related stress through learning communication skills, coping skills, and information about dementia (Schulz et al., 2020). While some of these programs have shown reductions in caregiver depression, most have minimal effect sizes (Schulz et al., 2020) and focus on reducing dysfunction (e.g., burden), rather than promoting holistic resilience factors (Palacio et al., 2020). Resilience literature suggests that taking a strengths-based approach to caregiver support may offer meaningful pathways to caregiver well-being, by promoting malleable factors such as positive affect, self-efficacy, and ways of coping (Palacio et al., 2020). Despite evidence of how the creative-arts therapies (CATs) such as dance/movement therapy (DMT) can promote positive aspects of well-being such as mood and coping in other populations, they remain underexplored for caregivers in their own right (Irons et al., 2020). CAT programs which have been explored often include the caregiver as a co-facilitator of the activity, alongside their loved one with dementia, and thus they may experience burden rather than respite (Irons et al., 2020). Importantly, proposed therapeutic mechanisms of DMT inherently correspond to resilience factors for caregivers (Champagne, 2024), providing a rationale for how DMT may help caregivers to focus on their own needs and build resources. However, scant if any research has designed or evaluated the benefits of DMT for caregivers.
The purpose of this exploratory research was to design, facilitate, and evaluate the impact of a 6-session, theory-driven DMT program on resilience for dementia caregivers and to understand their experiences of this program. The objectives and activities in the DMT sessions were informed by resilience theories and previous work on DMT for resilience in other populations. A pretest-posttest convergent mixed-methods design was used. Outcome measures included caregiving burden, resilience, and psychological flourishing. Weekly quantitative measures of active creativity and DMT therapeutic factors were also distributed to consider therapeutic mechanisms of the program. Qualitative data was captured through post-session journal entries and semi-structured debrief interviews.
Online survey data was collected at two time points from 10 dementia caregivers (before and after the DMT program). Repeated-measures t-tests were used to examine the changes in caregiver burden and well-being from before to after the DMT program. Results indicated that caregiver burden was significantly reduced from baseline to follow-up, as expected. However, increases in benefit finding, resilience, and psychological flourishing were not statistically significant. Pearson correlations of key study variables indicated that higher resilience immediately following DMT caused significantly lower caregiver burden at follow-up and was significantly associated with higher resilience at follow-up. Additionally, experiencing more DMT therapeutic factors was negatively associated with burden at follow-up, and positively associated with resilience and psychological flourishing at follow-up, with a medium effect size, but these correlations did not reach statistical significance.
Thematic findings from qualitative interviews and post-session journals revealed that the DMT program offered participants experiences of holistic engagement, liberation, and meaningful connection with others, which led to benefits of enhanced coping. Participants described their caregiving experiences as exhausting and overwhelming. They reported feeling constrained and that it was hard to find time for self-care. Participants contrasted their experiences in DMT with preexisting caregiver programs and emphasized how creative movement elicited benefits such as feeling “lighter” and empowered, gaining an attitude of acceptance, and emotional regulation. These findings suggest that DMT programs should continue to be designed and offered on a continual basis for dementia caregivers, for the unique ways in which movement provided a needed “release” and “liberation” which promoted experiences of emotional expression and improved coping.
Participants suggested that future iterations of the program should have more sessions, longer sessions to enable more deep processing and debriefing, and more social time. Together, the quantitative and qualitative findings suggest preliminary evidence of the potential for DMT to foster resilience factors and benefit caregiver well-being and coping. Participants in the present study emphasized their own surprise at how useful the modality of DMT was for their needs and urged for more DMT programs to be accessible to them
Developing tools to support older adults during climate-related emergencies
No full textWhat makes a person more likely to experience adverse health outcomes caused by extreme weather events? Can we identify those individuals at high risk before an extreme event happens? Natural hazards can lead to death and physical injury, as well as non-specific psychological distress, post-traumatic stress disorder, depression, and anxiety. By now, we have a good understanding of the main outcomes and some group-level risk factors associated with these events, such as low socioeconomic status, certain health conditions, and older age. These risk-factors are often used to develop vulnerability indices that can identify people at risk of adverse outcomes during an extreme event. However, these indices can be highly inefficient because not all individuals within each group live with the same vulnerability. Thus, it is essential that we use real-time, clinical, and demographic information to identify individuals at risk before an extreme weather event happens instead of relying on general group membership. The goals of this thesis are a) to understand the risk and protective factors that place older adults at higher risk of adverse health outcomes caused by natural hazards, and b) to develop indices to identify those individuals at highest risk. To achieve these goals, the thesis uses clinical assessments and focuses on acute, short-term health complications often a result of heat-related events and wildfire smokes. The thesis is divided in 3 studies and all studies used data from the interRAI Home Care and interRAI Contact Assessment instruments, which are comprehensive assessments to evaluate the person’s health needs and strengths.
Study 1 is an empirical investigation of the risk factors that place older adults at odds of living in homes with inadequate heating or cooling. The study uses longitudinal data and generalized estimating equations to explore risk factors such as demographic and social-economic characteristics as well as availability and quality of informal caregiver support for older adults with complex medical needs in Canada. These factors were used to identify geographic locations in Ontario with high percentages of home care clients living with inadequate heating or cooling at home. This is the first study that addresses the risks and protective factors associated with the thermal environment in home care clients, which is a population at high risk of adverse health outcomes during heat waves and cold spells.
Study 2 presents a new index to identify individuals that could be at risk of health complications during extreme weather events. The Brief Risk Index (BRI) was derived from data elements present in a screener that supports home care intake from community and hospital. It focuses on items indicating that individuals receiving home care services would have difficulty evacuating their homes during a time of crisis (e.g., cognitive impairment and difficulty performing activities of daily living). When compared with another tool that has been used in real-life situations, the BRI showed similar performance but with less items. This is the first index that targets the whole home care population in Canada, not only those receiving long-term services. Therefore, the BRI can be a game changing in emergency preparedness because of its efficiency and large target population.
Study 3 uses a similar approach as in Study 2 but focuses on home care clients at high risk of health complications caused by poor air quality. While the BRI is a more general tool, the Cardiorespiratory Vulnerability index (CRV) contains 16 items from a standardized assessment for home care clients and includes clinical characteristics often associated with negative health outcomes caused by poor air quality, such respiratory and heart diseases. This is the first index related to risks associated with air quality available in vulnerable populations in Canada, and one of the few worldwide. The study makes an important contribution to public health because climate change is accelerating the conditions under which wildfires and their adverse effects on air quality are more likely to happen.
Identifying individuals at high risk before an extreme weather event happens is a pressing problem in our society. This is particularly important today because of our aging population combined with the increase of the frequency, duration, and severity of extreme weather events caused by climate change. This thesis advances our knowledge of the risk and protective factors associated with extreme weather events and provides ready-to-use predictive tools to identify individuals that are more likely to experience health complications. The indices developed here can also be used to identify regions (neighborhoods) with higher concentration of people at risk, meaning that long-term, climate adaptation programs can be applied not only for individuals but also for geographic regions. Thus, the results from the three studies in this thesis represent a unique perspective in how our public health system could prepare for climate change, avoid negative outcome to vulnerable populations and show new directions for research
Resource Allocation for Reconfigurable Intelligent Surface assisted Wireless Communications
No full textReconfigurable intelligent surfaces (RIS) offer a promising solution to meet the growing demand for connectivity while ensuring stringent quality-of-service (QoS) requirements. An RIS consists of a 2D array of nearly passive reflecting elements, which can be configured to dynamically shape incident electromagnetic waves, thereby engineering the channel between a transmitter and a receiver. An RIS, which typically lacks active components (e.g., RF chains), provides a cost-effective, nearly passive solution for smart radio environments. However, its inability to perform advanced digital signal processing presents challenges, requiring channel state information (CSI) acquisition and RIS configuration optimization to be handled at the transmitter or receiver side, with control signals fed back to the RIS. Thus, efficient channel estimation and optimization of RIS reflection coefficients are essential for practical integration into existing communications systems. Subsequently, this research focuses on addressing these challenges by investigating resource allocation problems in RIS-assisted systems and developing efficient RIS configuration schemes for various practical scenarios.
First, we focus on RIS design in multi-user frequency-division-duplexing (FDD) and time-division-duplexing (TDD) systems, proposing a joint uplink-downlink RIS design where the same configuration supports both transmissions. In FDD, this is essential as uplink (UL) and downlink (DL) occur simultaneously, requiring a joint configuration. In TDD, while not strictly necessary, a joint design reduces feedback overhead, power consumption, and configuration periods associated with updating the RIS. To compute the trade-off between uplink and downlink rates achieved by a joint design, a weighted-sum problem is formulated and optimized using a developed block-coordinate descent (BCD) algorithm. The resulting uplink-downlink trade-off regions are investigated by numerical simulation to gain insights into different scenarios. For many considered scenarios, the proposed joint design is shown to bring significant improvements over the fixed-uplink (fixed-downlink) heuristic of using the RIS configuration optimized for uplink(downlink) to assist downlink (uplink) transmissions. Moreover, the proposed joint design substantially bridges the gap to the individual design upper bound of allowing different RIS configurations in uplink and downlink.
In the second part, we develop a learning-based framework that directly exploits noisy pilots to optimize a multi-user RIS system while accommodating different service priorities and fairness via user weights. Towards this goal, an adaptive beamforming configuration problem is formulated to generate the RIS system’s beamforming configurations that optimize the weighted sum-rate (WSR). Under mild regularity conditions, this problem is shown to attain a maximum. To learn approximate solutions, a novel hypernetwork-based beamforming (HNB) framework is proposed. Particularly, a beamforming network (BFN) exploits available information, including noisy pilots, to generate optimized beamforming configurations. Rather than learning one BFN, a hypernetwork is trained to dynamically generate BFN learning parameters from an input conditioning vector. When the conditioning vector is chosen as the user weights, the trained HNB can tune the BFN to the user weights without the need for retraining. Numerical experiments demonstrate that tuning allows the proposed HNB to perform close to a block-coordinate descent with perfect CSI benchmark and significantly outperform static learning where a BFN is directly trained to optimize beamforming configurations. Additionally, employing the HNB to also tune the BFN to location information considerably reduces the pilots needed to generate optimized beamforming configurations.
In the third part, to enable RIS implementation with diverse technologies, we develop RIS configuration schemes under relaxed hardware constraints. Particularly, we consider the case where an RIS is configured with discrete phase shifts and the amplitude response associated with an RIS element is non-linearly dependent on the phase shift introduced by the element. This RIS configuration problem is formulated as a constrained virtual-channel selection problem. Subsequently, it is demonstrated that the configuration problem, when restricted to subsets of the virtual channels where the maximum phase-variation is θmax < π, can be bounded between monotone upper bound (UB) and lower bound (LB) matroid-constrained problems. We illustrate discrete RIS configuration problems whose optimal solution satisfy this maximum phase-variation property. Moreover, under the maximum phase-variation property, performance guarantees are obtained using a low-complexity configuration scheme. Motivated by this, a practical low-complexity configuration framework is proposed to optimize general discrete RIS problems. Numerical experiments demonstrate the efficacy of the proposed RIS configuration scheme
The Use of Physical Exercise in the Hippocratic Corpus
No full textThis thesis sets out to prove that the Hippocratic Corpus uses exercise prescriptions for
the treatment of various pathologies, showing concordance with modern EIM (‘exercise is
medicine’) principles. I provide an analysis of both the Hippocratic views on exercise and the
prescriptions themselves from the following texts: Regimen, Internal Affections, and Regimen in
Acute Diseases. The fundamental purpose of this research project is to study the origins of
exercise therapy as a medical practice in the ancient world