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New developments for addressing class imbalance issue in classification tasks
No full textImbalanced datasets pose a significant challenge in machine learning, often resulting in biased models that inadequately learn from minority class instances. The Synthetic Minority Over-sampling Technique (SMOTE) is a well-established method to address this issue by generating synthetic samples for underrepresented classes. This Ph.D. thesis introduces several novel extensions to SMOTE, including Distance ExtSMOTE, Dirichlet ExtSMOTE, FCRP SMOTE, BGMM SMOTE, and Deep ExtSMOTE, each designed to enhance performance and manage complexities in various applications. Class imbalance, compounded by abnormal instances and the curse of dimensionality, adversely impacts model accuracy and reliability. Many existing techniques, including SMOTE, are insufficient for effectively handling these complexities. Our research develops new methodologies to tackle these challenges. DistanceExtSMOTE, Dirichlet-ExtSMOTE, FCRP-SMOTE, and BGMM-SMOTE use sophisticated techniques to handle abnormal instances and improve the quality of synthetic samples by leveraging weighted averages of neighbouring data points. These methods effectively manage outliers and noisy data, enhancing the robustness of the classification models. Additionally, DeepExt-SMOTE integrates these methods with autoencoders to further enhance accuracy when dealing with high-dimensional data. Empirical studies validate the effectiveness of these extensions, demonstrating significant improvements in classification performance across a range of metrics, including F1 scores, PR-AUC, and MCC. These advancements are particularly relevant in real-world applications, such as medical diagnosis, fraud detection, churn prediction, and fault detection. Addressing class imbalance with abnormal instances through these methods leads to more accurate and reliable predictions, ultimately contributing to better decision-making and improved outcomes in these critical areas. This work offers valuable tools for researchers and practitioners by advancing methodologies for handling class imbalance, abnormal instances, and high-dimensional data. The proposed techniques provide enhanced capabilities for managing complex classification tasks and achieving impactful results across diverse application domains.February 202
Environmental and spatial influences on abundance and size-at-age of Lake Whitefish in Great Slave Lake, Northwest Territories, Canada
No full textEnvironment plays a central role in shaping population dynamics and life history. Abiotic variables can provide insight into resource availability and habitat selection. In this thesis, I identified environmental drivers behind the abundance and size-at-age of the main commercial species, Lake Whitefish, Coregonus clupeaformis, in Great Slave Lake (GSL), Northwest Territories using Gaussian spatial random fields (SRFs) applied within a Bayesian framework. In Chapter 2, I developed standardized indices for numbers and mean weight of Lake Whitefish in the commercially fished western basin, resulting in more precise measures for catch-per-unit-effort to identify temporal trends in abundance. I estimated model parameters for both responses using soak time, smoothed year, and the random effects of SRFs by design, and considered the effects of water temperature, turbidity, distance to the nearest shore, and distance to the southern shore. The model for numbers did not include any environmental variables, but the model for mean weight was influenced by water temperature, distance to the nearest shore, and distance to the southern shore. Ontogenetic shifts in habitat were seen with higher densities of smaller, younger fish near the mouth of the Hay River, extending centrally into the basin, and with larger, older fish diffusing out to northern regions of the western basin. In Chapter 3, I explored the impacts of the environment on Lake Whitefish fork length-at-age. Using models for immature and mature fish, I examined the effects of sex, smoothed age, and the random effects of SRFs and capture year by design and considered the effects of water temperature, turbidity, and site depth. Water temperature was important regardless of reproductive stage, while sex had no effect. The SRFs depicted similar spatial distributions of size-at-age, with hotspots of greater size-at-age attributed to local movement away from higher densities of smaller size-at-age associated with riverine inputs along the southern shore. Chapters 1 and 4 provide background and context to interpret the results. The results of this thesis highlight the importance of river-lake interactions in GSL, which have been identified as driving the life history and population dynamics of the commercially and ecologically valuable Lake Whitefish.University of Manitoba Faculty of Graduate Studies tri-council top-up award
University of Manitoba Faculty of Graduate Studies tri-council masters supplement award
Fisheries and Oceans Canada Technical Expertise in Stock Assessment graduate student scholarshipFebruary 202
Methodological reflections on using photovoice and photo elicitation: Family members assess their perception of spaces in long-term care units
No full textPhotovoice is frequently used to engage participants of all ages on a wide range of social and community-based issues, yet few studies to date employ photovoice for the purpose of research on older adults and long-term care. In this study, we used an adapted version of photovoice combined with photo elicitation to investigate family members’ perceptions of special care unit spaces for residents with advanced dementia, as part of a broader evaluation of these units. Findings
demonstrate the value of this methodology in the context of long-term care and design. The discussion reflects benefits and limitations, as well as making recommendations for next steps.MITAC
Exploratory study of Google Nest Hubs in the long-term care setting in Manitoba
No full textIn the winter of 2021, the Centre on Aging provided Google Nest Hub devices to 80 personal care homes/supportive housing residences as a method of communication and entertainment for the residents and staf. Following this, we conducted an online survey to evaluate the experiences in setting them up and using them
Modeling simple epithelium tissue using tensegrity structures
No full textThe mechanical contribution to tissue behaviour is an important part of tissue development, homeostasis, and disease. Mechanical models of tissues are used in many areas of study including simulations, tissue engineering and the development of replacement parts for the body, and Optical Coherence Elastography where models are used for verification. Discovering some of the behaviors of tissue due to the structure alone will give more insight into the mechanics and behavior tissues. Structures that have tension as a main component of their architecture are called tensegrities and have different behaviors from normal structures that are mainly built to withstand compression.
A model consisting of a single layer of three cells and their attachments was developed using simple tensegrities as a base structure. Tensegrities are formed of a truss structure of strings and bars where the tensioned strings hold the structure upright. Having only two base parameters of elasticity one for the strings and one for the bars make the model more efficient computationally. The model was made into three forms representing squamish tissue – short model, cuboidal tissue – medium sized model, and columnar tissue – tall model. These models were then tested using physiological ranges of size, force, attachments, and prestrains in both tension and compression. The resulting force-distance and stress-strain curves were evaluated and found to have both linear and non-linear slopes. The stress-strain curves were shown to model real tissue in tension and compression. The models developed were compared to data from tissue and found to closely match the data for the tissue. The factors that influence the mechanics of the tissue model are the cytoskeleton, the cell attachments, and the base attachments, and these are the known factors that influence the mechanics of cell sheets. The models are adjustable by modifying the values of the strings and bars of the tensegrity models and the test conditions.February 202
Anaphylaxis
No full textAbstract Anaphylaxis is an acute, potentially fatal systemic hypersensitivity reaction with varied mechanisms and clinical presentations. Although prompt recognition and treatment of anaphylaxis are imperative, both patients and healthcare professionals often fail to recognize and diagnose its early signs. Clinical manifestations vary widely, however, the most common signs are cutaneous symptoms, including urticaria and angioedema. Immediate intramuscular administration of epinephrine into the anterolateral thigh is first-line therapy, and is always safe even if the diagnosis is uncertain. The mainstays of long-term management include specialist assessment, allergen avoidance measures, and the provision of an epinephrine auto-injector with an individualized anaphylaxis emergency plan. This article provides an overview of the causes, clinical features, diagnosis, and acute as well as long-term management of anaphylaxis.Key take-home messages • Anaphylaxis is the most severe form of a hypersensitivity reaction that is rapid in onset and potentially fatal. • Prompt recognition and treatment are critical in anaphylaxis. • The diagnosis is based primarily on clinical signs and symptoms. • The most common clinical manifestations are cutaneous symptoms, including urticaria, facial/lip swelling, erythema, and pruritus. • Referral to an allergist or immunologist should be considered for all persons who have experienced a previous anaphylactic episode. • Epinephrine is the drug of choice for anaphylaxis and should be given immediately, even if the diagnosis is uncertain; intramuscular administration into the anterolateral thigh is recommended. • There are no absolute contraindications to the use of epinephrine. • Up to 15% of anaphylaxis cases will have a biphasic response, with a second wave of symptomatology. • The mainstays of long-term treatment include: specialist assessment, avoidance measures, the provision of an epinephrine auto-injector and an individualized anaphylaxis emergency plan
Grassroots actions for rural revitalization: documenting a Miao family’s efforts toward autonomous and sustainable futures through biocultural design
No full textThis study documented the efforts of a Miao (Hmong) family in Guizhou, China, to create autonomous and sustainable rural futures by developing diverse economic pathways rooted in local biocultural resources. Amidst the rapid sociocultural and economic changes in rural China over recent decades, this family from Queniao — a remote Miao village in the core of Leigong Mountain Nature Reserve — has undertaken a series of agritourism and conservation projects under the business entity Manyou Farm (慢友农场) since 2019, focusing on local agricultural and food practices, rural experiential activities, ecological tea, Miao heritage crafts, education, and advocacy.
Using a case study approach complemented by ethnographic methods, this study explored the emergence, organization, and impact of these agritourism and conservation projects and the embedded meanings, values, knowledge, and skills. It also identified the drivers and constraints of these projects. The concepts of autonomy, biocultural design, and sustainability transitions were engaged to interpret the family’s motivations, encapsulate Manyou Farm’s projects, and contextualize the success and significance of these efforts.
The findings and implications fall into three dimensions. First, Manyou Farm’s projects offer the family significant security and well-being from local ways of life while maintaining integration with mainstream economic systems and cultural life. This highlights the inadequacy of hierarchical developmental discourses and the agency and strategism of communities in pursuing their own paths to desired futures. Second, Manyou Farm is identified as a sustainability-driven, autonomy-centered, and dynamically organized enterprise, whose distinctiveness has contributed to its positive, multidimensional impact, underscoring the benefits for rural developmental projects to support multi-actor, innovative processes. Third, Manyou Farm’s case highlights the role of state and regional developmental schemes in enabling grassroots tourism initiatives and the yearnings among urban residents for environmental and food quality, community connections, and cultural authenticity. Three emerging values, processes, and relations of sustainability — slow, urban-rural integration, and multifunctionality — are derived from this case study.University of Manitoba Graduate Student Entrance Scholarship
Berkes Graduate Scholarship in Community-Based ResearchFebruary 202
Partnering for community development: an interactive relationship framework for assessing higher education institution impact in the local community
Get PDFThe involvement of higher education institutions (HEIs) in the local community is a conflicted topic. Deeply connected to notions of “public good,” touted as drivers for economic prosperity and societal progress, yet subject to suspicions of irrelevance and exploitation, HEIs have a complex relationship with the communities in which they are embedded. Through the lenses of place building theory, social field theory, and community development theory, this study uses an interdisciplinary conceptual framework to examine the complex topics of community-HEI relationships and their impact on systemic structural change at the local level. A mixed methods research design utilizes document analysis, surveys, and semi-structured interviews to collect data relevant to the goals, actions, expected outcomes, and observed impacts of a single HEI case study and its cooperation within the local community. Collected data for the case institution, located in Winnipeg, Canada, is compared with the city’s community development goals, which are derived from the United Nations Sustainable Development Goals (UN SDGs) to determine areas of alignment and divergence. Relationship qualities and agency to reduce systemic barriers are noted through the interactions between university faculty members, university administrators, members of City Council, and community organization members and examined through the conceptual frameworks to arrive at a new understanding of the institution’s community development impact. Results show that despite the aspirational tone of university documents to be a transformative force in the community, members of the community are largely unaware of its social impact, with some suggesting that it increases systemic barriers rather than removing them. While the case-specific data is unique to the institution, the conceptual framework provides an adaptable evaluation approach that may be used by other institutions in their various contexts, creating a new way for institutions and their communities to assess higher education’s impact in relation to local community development and localized SDG attainment.February 202
“I think of it as planting seeds”: challenging patient-provider discussions about COVID-19 vaccination: a qualitative study
Get PDFBackground: Vaccination has been essential in mitigating the worst effects of the COVID-19 pandemic in Canada. Healthcare providers can play a crucial role in promoting COVID-19 vaccination by discussing immunization, addressing patients’ questions, and providing them with relevant information. However, some segments of the public remained hesitant towards COVID-19 vaccination during the pandemic, reflecting an information environment crowded with misinformation and political polarization. This study examines challenging clinical discussions that healthcare providers had with patients hesitant about COVID-19 vaccines. It focuses on obstacles to fruitful conversations and strategies to overcome them, which can extend into ongoing vaccine-related conversations outside a pandemic context.
Methods: Researchers conducted individual interviews with ten healthcare providers during the pandemic (January-May 2022) in the province of Manitoba, Canada. Participants were recruited using invitations distributed via professional organizations and networks. The recruited sample included primary care physicians, nurse practitioners, and a specialist provider who had recently discussed the COVID-19 vaccine with patients. Study participants were asked about their challenging conversations regarding the COVID-19 vaccine with patients and how they navigated these experiences. The resulting data were analyzed using NVivo12 to capture and organize salient themes.
Results: Healthcare providers reported that COVID-19 vaccines have prompted new forms of vaccine hesitancy and resistance compared to existing vaccines, particularly due to concerns about the integrity of the vaccine (e.g., vaccine novelty, ingredients) or related public policy (i.e., vaccine mandates). Providers reported a significant rise in hostility from patients who were staunchly hesitant and experienced moral injury, burnout, and an emotional toll from witnessing disregard for public health. Participants indicated that they attempted to employ motivational interviewing strategies and shared decision-making and voiced desires for further training in such approaches. Some participants found mixed success with using decision aids or used improvised strategies to facilitate discussions.
Conclusion: Motivational interviewing and shared decision-making strategies proved valuable to healthcare providers in navigating challenging discussions, addressing/acknowledging patient concerns, and preserving relationships. Healthcare providers need to be better supported with training in these strategies and in navigating the moral/emotional/physical consequences of experiencing a global health crisis in clinical settings
Effect of seed composition and growth pressure on Au-assisted TiO2 nanowire growth
Get PDFThis thesis investigates the vapor–adsorbate–solid (VAdS) growth of TiO₂ nanowires and demonstrates how pressure and seed composition govern nanowire formation and morphology. Unlike previously reported open-flow systems, the closed, no-flow geometry used here enabled growth across a broad sealing pressure range, from near atmospheric pressure down to 0.4 Pa. The most favorable growth was observed between 10 and 1000 Pa, likely due to an optimal oxygen partial pressure that promotes TiO₂ substrate evaporation. Beyond pressure, seed composition emerged as a key parameter for tailoring nanowire morphology. In our previous work, pure Au seeds produced bead-like nanowires oriented along [110]TiO₂, while incorporating Ag into the Au seed led to the formation of Ag-rich segregation domains, shifting the morphology toward prismatic TiO₂ nanowires and underscoring the influence of seed chemistry. Building on this finding, the present study further explores the effect of seed composition by examining the incorporation of Ni and Ag into Au seeds. In Au–Ni seeds, the addition of Ni promoted endotaxial embedding of Au nanoparticles, altering the Au–TiO₂ interface and producing new orientation relationships. These embedded nanoparticles exhibited irregular shapes in bead-like [110]-oriented nanowires, while well-faceted nanoparticles bounded by low-index planes formed in prismatic -oriented nanowires, underscoring the role of crystallographic factors in addition to growth oscillations. In Au–Ag seeds, local compositional heterogeneity was shown to dictate nanowire morphology, as Ag-rich regions at the junction of {101 ̅} and {11 ̅0}TiO₂ facets promoted site-specific nucleation and enabled the transition from bead-like TiO₂ nanowires to prismatic TiO₂ nanowires. Spectroscopic analyses revealed evidence of Ag–O interactions, confirming Ag’s stronger affinity for oxygen and its role in stabilizing prismatic growth fronts. Overall, this work establishes a framework for tailoring oxide nanowires through controlled VAdS growth and seed-induced interfacial engineering, offering pathways for the rational design of nanostructures with applications in electronics, photonics, and catalysis.University of Manitoba
Mitacs AccelerateFebruary 202