Browsing by Author "Pauchard, Yves"

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    Compensation of metallic implant related artifcats in magnetic resonance imaging
    (2004) Pauchard, Yves; Mintchev, Martin P.; Smith, Michael Richard
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    Design, Development, and Usability Testing of Robin’s Nest Platform Supporting the SENSE Program for Addressing Moral Injury in Nurses and Social Workers
    (2025-01-29) Savalanpour, Majid; Moshirpour, Mohammad; Duffett-Leger, Linda; Drew, Steve; Pauchard, Yves
    The COVID-19 pandemic has exacerbated mental health challenges for nurses and social workers, exposing them to increased risks of stress, moral injury, and psychological disorders such as anxiety and Post-Traumatic Stress Disorder (PTSD). To address this critical need, with the generous funding support from the Government of Alberta, our interdisciplinary team of researchers in Nursing, Social Work, Electrical and Software Engineering, and Kinesiology initiated the design, development, and usability evaluation of the Robin’s Nest telehealth platform. This platform hosts the Supporting Emotional wellness in Nurses and Social workers E-mental health (SENSE) program and was developed using a User-Centered Design (UCD) approach, co-designed with participants. This innovative e-health intervention integrates virtual Cognitive Behavioral Therapy (CBT), stress monitoring using wearable technology, and real-time feedback to provide personalized mental health support. Usability evaluation, as a key element of the UCD approach, plays a pivotal role in assessing the platform's effectiveness. This research employs a multi-method usability evaluation approach, combining quantitative assessments using the mHealth App Usability Questionnaire (MAUQ), qualitative insights from focus group interviews, and Heuristic Testing. The findings demonstrate that the platform successfully meets users’ needs, achieving high usability scores and user satisfaction (median responses: 4 out of 5). Thematic analysis conducted during the usability evaluation highlights the platform’s effectiveness and high usability. Recommendations for improving usability, identified through this analysis, include enhancing communication features, resolving learning management system login issues, and refining the video conferencing interface design. This research underscores the importance of usability in e-health interventions and offers actionable insights for future advancements in digital mental health solutions.
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    Expedited Load Tests for CI/CD Microservice Applications
    (2024-09-06) Cooper, Quinn; Krishnamurthy, Diwakar; Amannejad, Yasaman; Pauchard, Yves; Drew, Steve
    In recent years, microservices have become a dominant architecture in software development, offering scalability, modularity, and agility to development processes. However, ensuring optimal performance before deployment poses a significant challenge, particularly in the fast-paced environments of Continuous Integration/Continuous Deployment (CI/CD) pipelines. Traditional performance testing methods, which rely on synthetic scenarios and lengthy testing processes, can be difficult to adopt in environments where testing needs to be both realistic and quick. To address the need for accurate and responsive testing, my work proposes and implements an innovative framework that uses real-world usage traces to identify and execute a small yet essential set of performance tests. This approach aims to seamlessly integrate with CI/CD workflows, providing developers with quick feedback on performance issues and scalability constraints that may arise from changes to one or more microservices. Through a series of empirical evaluations, I compare the effectiveness of six techniques using 12 real-world traces chosen based on their timeseries characteristics. My work aims to identify a set of performance tests that can capture historically observed system behaviour and be executed within a specified time budget. In this work, I present and test 6 different techniques for load test generation. Of the 6 techniques tested, Interval Sampling (IS) was the most reliably accurate for all traces tested. Using this technique, I was able to replicate the response time distribution of a 24-hour test on our custom testbench within just a five-minute test, achieving a mean relative percent error of only 1.12% and 2.73% at the 90th and 95th percentiles. This considerable decrease in time and resources necessary for load testing and response time modelling demonstrates the efficiency and effectiveness of my approach.
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    In vivo monitoring of longitudinal changes in bone micro-architecture using high-resolution peripheral computed tomography
    (2012) Pauchard, Yves; Vigmond, Edward J.; Boyd, Steven
    Osteoporosis is a disease characterized by low bone quality and increased risk of fracture. In order to improve osteoporosis treatment, it is essential to monitor bone quality and its changes over time in healthy, diseased and treated bones. V/ith the recent development of in vivo high-resolution peripheral quantitative computed tomography (HR-pQCT) it became possible to capture bone micro-architecture, an important determinant of bone quality, in humans. The aim of this dissertation was to propose new ways to analyze the resulting time series of three-dimensional (3D) image data to gain novel insight into bone behaviour. In a first step. a novel method for tracking and predicting micro-architectural changes using deformable image registration was validated. Applied to an osteoporotic and healthy pre-clinical model, this study demonstrated successful prediction of 3D archi­tecture based on a time series of images without knowledge of disease state. Prior to extending the monitoring of changes to human bone, the problem of subject motion artifacts in HR-pQCT imaging was addressed. An automatic, fast and objective method was developed to quantify three separate components of subject motion using projection data. \i\Tith this tool, guidelines for image quality management in the pres­ence of subject motion were established. Understanding and managing these artifacts is pivotal for guaranteeing consistent image quality in large multi-centre studies. In ad­dition to motion quantification, a novel method for compensating movement artifacts was developed. The proposed method for motion compensation paves the way for future research into improving image quality, potentially increasing viable data benefiting drug trials and studies of rare diseases with small sample sizes. Lastly, in order to monitor bone micro-architecture changes in humans, an automated registration methodology was devised to align 3D HR-pQCT images and techniques to visualize local architectural changes were developed. It was possible to visualize local changes due to normal bone remodelling, and in response to osteoporosis treatment, aiding interpretation of changes in traditional bone quality parameters. The developed methods form the foundation for tracking bone adaptation over time, ultimately further­ing our understanding of bone mechanisms in humans.
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    Probabilistic Causal Data Modeling of Barriers to Accessibility for Persons with Disabilities in Canada
    (2024-12-02) Zakir, Mouri; Yanushkevich, Svetlana; Yanushkevich, Svetlana; Pauchard, Yves; Fast, Victoria Veronica
    This thesis addresses the pressing social issue of accessibility for persons with disabilities by creating AI models using the national survey data, with a methodological two step process. The contributions of this thesis include (a) a causal reasoning framework aiming to provide an understanding of the prevalence of barriers and challenges faced by persons with disabilities when accessing federal services and facilities; and (b) network-based approach that utilizes empirical data to provide a holistic assessment of the causality among demographic features (e.g. age, gender, type of disability) and accessibility. The statistical method utilizes Structural Equation Modeling supported by Exploratory Factor Analysis. For causal probabilistic modeling, Bayesian Networks are employed as a straightforward and compact way to interpret knowledge representation. This causal reasoning approach analyzes the nature and frequency of encountering barriers based on data to understand the risk factors contributing to pressing accessibility issues. Furthermore, to evaluate the network performance and overcome data limitation, synthetic data generation techniques are applied to create and validate artificial data built on real-world knowledge. The proposed framework aims to provide reasoning to understand the prevalence of physical, social, communication or technological barriers encountered by persons with disabilities in their daily lives. This thesis contributes to identifying areas for prioritization in facilitating accessibility regulation and practices to build an inclusive society.
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    The utility of multi-stack alignment and 3D longitudinal image registration to assess bone remodeling in rheumatoid arthritis patients from second generation HR-pQCT scans
    (2020-04-07) Brunet, Scott C; Kuczynski, Michael T; Bhatla, Jennifer L; Lemay, Sophie; Pauchard, Yves; Salat, Peter; Barnabe, Cheryl; Manske, Sarah L
    Abstract Background Medical imaging plays an important role in determining the progression of joint damage in rheumatoid arthritis (RA). High resolution peripheral quantitative computed tomography (HR-pQCT) is a sensitive tool capable of evaluating bone microarchitecture and erosions, and 3D rigid image registration can be used to visualize and quantify bone remodeling over time. However, patient motion during image acquisition can cause a “stack shift” artifact resulting in loss of information and reducing the number of erosions that can be analyzed using HR-pQCT. The purpose of this study was to use image registration to improve the number of useable HR-pQCT scans and to apply image-based bone remodeling assessment to the metacarpophalangeal (MCP) joints of RA patients. Methods Ten participants with RA completed HR-pQCT scans of the 2nd and 3rd MCP joints at enrolment to the study and at a 6-month follow-up interval. At 6-months, an additional repeat scan was acquired to evaluate reliability. HR-pQCT images were acquired in three individual 1 cm acquisitions (stacks) with a 25% overlap. We completed analysis first using standard evaluation methods, and second with multi-stack registration. We assessed whether additional erosions could be evaluated after multi-stack registration. Bone remodeling analysis was completed using registration and transformation of baseline and follow-up images. We calculated the bone formation and resorption volume fractions with 6-month follow-up, and same-day repositioning as a negative control. Results 13/57 (23%) of erosions could not be analyzed from raw images due to a stack shift artifact. All erosions could be volumetrically assessed after multi-stack registration. We observed that there was a median bone formation fraction of 2.1% and resorption fraction of 3.8% in RA patients over the course of 6 months. In contrast to the same-day rescan negative control, we observed median bone formation and resorption fractions of 0%. Conclusions Multi-stack image registration is a useful tool to improve the number of useable scans when analyzing erosions using HR-pQCT. Further, image registration can be used to longitudinally assess bone remodeling. These methods could be implemented in future studies to provide important pathophysiological information on the progression of bone damage.