30921 research outputs found
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Advancing assembly sequence planning by genetic algorithm and Q-learning method
No full textAssembly sequence planning (ASP) determines the order of the assembling components of a product. Existing ASP methods have the limitation in planning complex products with high computational costs and inefficient optimization solutions. This thesis applies different variants of Genetic Algorithm (GA) as well as Q-Learning-based Genetic Algorithm (QLGA) to address these challenges. GA, like other metaheuristics, is problem-dependent and typically requires tuning for specific problems. By incorporating Q-learning capabilities into GA, the performance of GA can be enhanced, especially for solving NP-hard ASP problems. Different versions of GA and QLGA with various crossover operators and selection mechanisms are compared to evaluate the proposed approaches through case studies. The results show that QLGA outperforms traditional GA in terms of convergence rate and efficiency. ASP can be significantly improved when Q-learning techniques are combined with traditional GA methods, providing a versatile and efficient solution for product assembly planning.October 202
Bangladeshi English for Academic Purposes (EAP): novice and experienced teachers’ perspectives on written corrective feedback
No full textAbstract
This study aimed to identify the factors that shape novice and experienced teachers’ beliefs about written corrective feedback and the factors that influence teachers’ practices with students’ writing in the Bangladeshi context. The study intended to: 1) provide in-depth data on writing teachers’ perspectives of written corrective feedback (WCF) and how those perspectives evolved; 2) clarify writing teachers’ feedback preferences and the factors that determine how they approach those specific techniques; 3) show the challenges instructors encounter in practicing written corrective feedback on students’ writing; and 4) identify factors influencing teachers’ WCF practices.
The study’s findings demonstrate that teaching experience has a significant impact on shaping teachers’ beliefs about WCF practices because it gives instructors access to many additional influences, such as having attended more professional developments sessions and interacted with professionals within developed networks. Furthermore, teacher education programs and professional development sessions do not equally contribute to developing novice and experienced teachers’ beliefs, because new teachers have fewer professional development opportunities than experienced instructors. As students themselves, the experienced teachers received direct WCF on their papers—primarily on grammar problems—but they now provide indirect feedback on substance and structure to their own students. They adjusted their WCF practices over time as they gained teaching expertise. However, prior learning experience has a considerable impact on how new teachers form their attitudes about WCF. Institutional variables have a greater impact on new teachers’ WCF practices than on those of experienced ones. Moreover, the experienced group prefers to provide indirect WCF and focus on global issues of writing such as essay structure, whilst the novices prefer to provide direct feedback on local concerns such as sentence structure and spelling. Finally, instructional issues like class time and work pressure seem to be difficult for both beginner and experienced teachers, as they must balance class time and work pressure, though reluctance to provide adequate WCF has a divergent trend. However, institutional challenges are more prominent among new teachers. University administrators in Bangladesh, practicing writing instructors, and department heads of advanced teaching and learning centers may benefit from the outcomes of this study.I only received a research completion award.October 202
Electrochemical quantification of Ochratoxin A in canadian grain
No full textThe objective of this thesis is to quantitatively detect ochratoxin A (OTA) in Canadian grain by electrochemistry. To this end, two distinct sensing approaches were developed.
In the first approach, a simple label-free sensor was designed to detect OTA. The oxidation mechanism of OTA was investigated using cyclic voltammetry (CV), and the impact of pH on the sensor's response to OTA was explored. Experimental design techniques were employed to optimize the analytical signal. OTA was successfully detected in wheat extracts using differential pulse voltammetry (DPV). The calculated analytical limit of detection (LOD) and limit of quantification (LOQ) were 57.2 nM and 190.6 nM, respectively.
For the second approach, a gold electrode (GE) was modified with an OTA-specific aptamer to create a selective aptasensor. Methylene blue (MB) was linked to the aptamer, and the cathodic peak resulting from the reduction of MB at the aptasensor's surface was recorded as the analytical signal using square wave voltammetry (SWV). The surface packing density of the sensor was calculated to optimize the OTA aptamer concentration during sensor modification. The proposed aptasensor detected OTA in phosphate-buffered saline (PBS) media with a lowest measurable concentration (LMC) of 3.44 µM and a lowest quantifiable concentration (LQC) of 10.42 µM. The aptasensor demonstrated its capability to detect OTA in spiked wheat extracts with acceptable accuracy.
The thesis concludes by comparing the two developed methods and discussing future research opportunities to enhance the performance of the aptasensor.May 202
Win-Shield Combined Biometric and Chemical Sensor System
No full textThe Win-Shield combined biometric and chemical sensor system is a capstone and proof-of-concept project done by the Biosystems Engineering Students of the University of Manitoba over the course of 8 months. The project aims to enhance the safety of isolated industrial workers by providing simultaneous real-time monitoring of vital signs and exposure to hazardous chemicals to both the wearers and their supervisors. Currently, there are no commercially available products designed with these all of these functions for industrial purposes, as most are only intended for recreational or hospital purposes.
The system comprises of three subsystems, including a comfort pad with biometric sensors, a chemical sensor unit, and an ESP32ESP32 Devkit microcontroller to process data from the sensors. It can integrate seamlessly into a universal headband to be worn under a welding mask. Key features include:
• Having a light weight of 500 grams or under.
• Broad applicability fitting 85% of the Canadian population.
• Precise vital signs monitoring with temperature accuracy within 0.3°C and 2%.
• Heart rate and blood oxygenation accuracy exceeding 97% and 98.85% respectively (Sari et al. 2021).
• Alarming chemical exposure thresholds align with 15-minute short term exposure guidelines set by the Government of Manitoba.
The design has been verified by various tests resembling CSA standard verification procedures as much as possible under the constraints of time, budget, and resources. For the temperature sensor, immersion in an ice water bath alongside a high-accuracy thermometer assessed accuracy and response time. The heart rate and blood oxygenation sensor has been benchmarked against a smartwatch due to its biometric accuracy. Humidity sensor testing involved controlled environments using salt mixtures to establish fixed relative humidity. Gas sensors have undergone calibration, followed by simple bump testing and limited time response tests, in which they were exposed to triggering gas concentrations within known environments to evaluate response times.
The testing section of the report extends its focus to physical tests for the overall system. Environmental temperature, drop, and vibration tests were conducted to ascertain potential impacts on system operation. These tests collectively ensure a robust assessment of the sensor system's reliability and functionality in diverse conditions.
Lastly, the limitations that were found to have impacted the design process have been summarized, along with suggestions for potential solutions to these limitations. Additionally, potential next steps for developing this project have been included should the project continue into further design iterations
A qualitative evaluation of stakeholder perspectives on sustainable financing strategies for ‘priority’ adolescent sexual and reproductive health interventions in Ghana
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Background
Adolescent sexual and reproductive health (ASRH) interventions are underfunded in Ghana. We explored stakeholder perspectives on innovative and sustainable financing strategies for priority ASRH interventions in Ghana.
Methods
Using qualitative design, we interviewed 36 key informants to evaluate sustainable financing sources for ASRH interventions in Ghana. Thematic content analysis of primary data was performed. Study reporting followed the consolidated criteria for reporting qualitative research.
Results
Proposed conventional financing strategies included tax-based, need-based, policy-based, and implementation-based approaches. Unconventional financing strategies recommended involved getting religious groups to support ASRH interventions as done to mobilize resources for the Ghana COVID-19 Trust Fund during the global pandemic. Other recommendations included leveraging existing opportunities like fundraising through annual adolescent and youth sporting activities to support ASRH interventions. Nonetheless, some participants believed financial, material, and non-material resources must complement each other to sustain funding for priority ASRH interventions.
Conclusion
There are various sustainable financing strategies to close the funding gap for ASRH interventions in Ghana, but judicious management of financial, material, and non-material resources is needed to sustain priority ASRH interventions in Ghana
Adaptive designs in clinical trials: a systematic review-part I
Get PDFAbstract Background Adaptive designs (ADs) are intended to make clinical trials more flexible, offering efficiency and potentially cost-saving benefits. Despite a large number of statistical methods in the literature on different adaptations to trials, the characteristics, advantages and limitations of such designs remain unfamiliar to large parts of the clinical and research community. This systematic review provides an overview of the use of ADs in published clinical trials (Part I). A follow-up (Part II) will compare the application of AD in trials in adult and pediatric studies, to provide real-world examples and recommendations for the child health community. Methods Published studies from 2010 to April 2020 were searched in the following databases: MEDLINE (Ovid), Embase (Ovid), and International Pharmaceutical Abstracts (Ovid). Clinical trial protocols, reports, and a secondary analyses using AD were included. We excluded trial registrations and interventions other than drugs or vaccines to align with regulatory guidance. Data from the published literature on study characteristics, types of adaptations, statistical analysis, stopping boundaries, logistical challenges, operational considerations and ethical considerations were extracted and summarized herein. Results Out of 23,886 retrieved studies, 317 publications of adaptive trials, 267 (84.2%) trial reports, and 50 (15.8%) study protocols), were included. The most frequent disease was oncology (168/317, 53%). Most trials included only adult participants (265, 83.9%),16 trials (5.4%) were limited to only children and 28 (8.9%) were for both children and adults, 8 trials did not report the ages of the included populations. Some studies reported using more than one adaptation (there were 390 reported adaptations in 317 clinical trial reports). Most trials were early in drug development (phase I, II (276/317, 87%). Dose-finding designs were used in the highest proportion of the included trials (121/317, 38.2 %). Adaptive randomization (53/317, 16.7%), with drop-the-losers (or pick-the-winner) designs specifically reported in 29 trials (9.1%) and seamless phase 2-3 design was reported in 27 trials (8.5%). Continual reassessment methods (60/317, 18.9%) and group sequential design (47/317, 14.8%) were also reported. Approximately two-thirds of trials used frequentist statistical methods (203/309, 64%), while Bayesian methods were reported in 24% (75/309) of included trials. Conclusion This review provides a comprehensive report of methodological features in adaptive clinical trials reported between 2010 and 2020. Adaptation details were not uniformly reported, creating limitations in interpretation and generalizability. Nevertheless, implementation of existing reporting guidelines on ADs and the development of novel educational strategies that address the scientific, operational challenges and ethical considerations can help in the clinical trial community to decide on when and how to implement ADs in clinical trials. Study protocol registration https://doi.org/10.1186/s13063-018-2934-7
Neural network thermodynamics
Get PDFIn this work, the variational Monte Carlo (VMC) method using the restricted Boltzmann machine (RBM), a feed-forward neural network, is investigated to allow for the computation of finite-temperature results of quantum spin models in one and two dimensions. To accomplish this task, there are, at least, three different approaches possible that are discussed and compared for the Heisenberg model in one dimension before they are deployed to the Heisenberg and the - model in two dimensions. In the latter case, the correct detection of the presumed finite-temperature phase transition is studied. The three different types of methods studied in a variational setting are comprised by the purification method, the sampling method, and the use of variational thermal pure quantum states and thus the notion of quantum typicality. In the proceeding of this study, the reason for choosing the RBM as the predestined variational ansatz is motivated by general (artificial) neural network theory and investigations and findings related to the ground state optimization method. In the purification and the sampling method, finite temperature correlation functions for the one-dimensional Heisenberg model are computed successfully and even the free energy is attainable. Unfortunately, the idea of using quantum typicality in a combined variational ansatz, using the RBM and a pair-product ansatz, is shown to lead to inaccurate results at low temperatures due to the high entanglement entropy of those variational states. The issue seems to be persistent for any variational ansatz wave function and renders the applicability of quantum typicality in a variational setting highly problematic. To complete this investigation, the real-time evolution at infinite temperature is studied and the unfavourable scaling of the number of hidden units documented. Finally, the purification and the sampling method are applied to the - model on the square lattice. Unfortunately, the computation of accurate results for very low temperatures is difficult due to an increase in the rejection probability, an issue related to the Monte Carlo sampling and known as critical slowing down.October 202
Brain Injury in Manitoba (BIMb; 2022-2024) project: Project phase 1 stakeholder report & recommendations
No full textAcquired brain injury (ABI) is one of the largest diagnostic groups and leading causes of disability around the world, including in Manitoba. Brain injury can affect any area of a person’s functioning, including cognitive/thinking, emotional/mental health, physical, immunological, and behavioral functioning. Due to the widespread effects, ABI can also then change any area of life including family life, housing, employment, leisure transportation, and community participation, with changes often lasting a long time and for many are lifelong changes. These long-term challenges are strongly associated with many detrimental consequences, especially when needs are not met. This includes high rates of homelessness and secondary health concerns. Thus, changes after ABI can create challenging situations for not only the person but also for their families, close others, and communities. Of concern to all citizens, these unmet needs after ABI are costly and have negative effects not just on those directly impacted by ABI, but to all society.
In Manitoba people living with ABI, their families, and their close others have many unmet needs directly related to ABI. Brain injury supports and services are chronically underfunded to meet the immediate and long-term needs of ABI-survivors (those living with brain injury), and since the COIVD-19 pandemic ABI supports and services have declines. Of great concern, there lacks a strategy in Manitoba of how to meet the needs of people affected by ABI. While in Canada a bill is progressing through the federal government (i.e., Bill C-277: A national strategy on brain injury), we do not have information on what an effective strategy for brain injury in Manitoba should be.
Therefore, we developed the Brain Injury in Manitoba (BIMb) project, and to do this project we formed a diverse and multi-disciplinary project team of people with lived, work, and research-related ABI experience. The goal of the BIMb project is to develop a unified understanding, focus, and recommendations for innovative action, research, advocacy, and policy change that will improve the supports, services, and the quality of life of Manitobans living with ABI. We have addressed our project goal in the Winnipeg region, which was Phase 1 of the BIMb project and is the focus of this report.March of Dimes Canada (Manitoba Region); University of Manitoba (Lisa Engel Research Startup funds
Application of multispectral remote sensing to monitoring water quality of urban stormwater retention ponds
No full textStormwater retention ponds are used to reduce the burden on storm sewer systems during heavy rain events and filter pollutants, although they are prone to eutrophication and cyanobacterial blooms. Two nearby ponds with contrasting designs (traditional vs. naturalized) in Winnipeg, Manitoba, were regularly sampled from late spring to early fall for two years using a boat and tested for a suite of water quality parameters in order to compare them. Near-surface measurements of water reflectance were also collected via remote sensing using a handheld spectroradiometer.
A drone equipped with a multispectral sensor was deployed prior to sampling to collect imagery of the ponds in order to evaluate the utility of airborne remote sensing for monitoring water quality. Compared to established remote sensing methods such as satellites and handheld spectroradiometers, drones are a relatively new technology that have potential to fill a niche for monitoring small water bodies or areas of interest at high spatial and temporal resolutions. Cloud-free skies with low wind were considered ideal flight conditions, however, data were also collected under suboptimal conditions.
Results showed that the naturalized retention pond typically had lower concentrations of chlorophyll-a and total suspended solids at its surface layer and was dominated by green algae and diatoms as opposed to cyanobacteria at the traditional pond. Water quality tended to decline throughout the sampling season at both ponds, but the traditional pond experienced an intense cyanobacterial bloom in 2021. At the naturalized pond, the timing of water quality decline coincided with the senescence of green algae and pondweed along its surface layer.
Results of linear regressions between select waveband ratios and chlorophyll-a or total suspended solids demonstrated that while the near-surface method was typically stronger, airborne remote sensing was viable and even outperformed it under certain conditions. The influence of suboptimal conditions on regression strength varied, as did the performance of wavebands among ponds, however, at least one option performed moderately well in all cases, and under ideal circumstances R2 values were exceptional. Three key waveband ratios performed well under numerous circumstances: red-edge to red, red-edge to green, and near-infrared to red.October 202
Arctic whale mortality: understanding modern population losses for the future
No full textThe remote, ice-covered habitat and reclusive nature of Arctic cetaceans have led to a gap in
knowledge about species ecology. In rare instances where Arctic cetaceans can be spotted,
information about their population structure and biology can be gleaned through observation;
however, direct observations are difficult in high ice cover. Ice entrapments, where cetaceans are
crowded under increasing ice cover until escape or drowning, have given insight into cetacean
populations since the 18th century, and today new genetic analyses can allow us to reexamine the
population structure of these Arctic species and add to previous research on ice entrapments and
narwhal social structure. In this thesis’ second chapter, I first review 138 cetacean ice entrapment
occurrences globally and show that ice entrapments are a significant source of mortality for
cetaceans, killing more than 18,500 individuals in 13 different species since 1900. In the third
chapter, I use population genetics to study the social structure of the Canadian Arctic narwhal
(Monodon monoceros) from a 2008 ice entrapment. Through pair-wise relatedness and cluster
analysis, I determined that within an ice-entrapped herd (n=245), there were 8 genetically related
clusters with an average size of 30.6, indicating that the species may follow a fission-fusion
social structure like other smaller, social cetaceans. This work may contribute to species
management decisions and be valuable for emergency management of ice entrapments.May 202