Faculty of Graduate Studies Online Theses

Permanent URI for this collectionhttps://hdl.handle.net/10222/11163

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Open Access
TOWARDS DEVELOPING STANDARDIZED PRECISION AGRICULTURE BOOM SPRAYER VIA HYBRID COMMUNICATION NETWORK FOR REAL-TIME SPOT APPLICATION
(2025-04-30) Motalab, Mozammel Bin; Not Applicable; Doctor of Philosophy; Faculty of Agriculture; Not Applicable; Viacheslav Adamchuk; Not Applicable; Alex Martynenko; Karama Al-Tamimi; Ahmad Al-Mallahi
The transition of boom spraying towards spot application under precision agriculture schemes faces challenges due to the large volume of data generated by a large number of sensing and actuation devices. This research focuses on developing a universal communication network for real-time spot application, using Controller Area Network (CAN) at its core, offering the advantages of potentially error-free communication and seamless integration of machine vision systems into different boom sprayers. To handle the narrow bandwidth characteristic of CAN, a novel electronic control unit (ECU) was developed to encapsulate pest detection results into CAN data frames based on detected pest locations in images received from one machine vision system consisting of multiple cameras. The machine vision data were transmitted through UART to identify the number of nozzles to be actuated via CAN. The ECU was designed to accommodate different machine vision systems with varying camera counts and image resolutions. For real-time control, the ECU extracted data every 40 ms and constructed CAN frames in two separate threads simultaneously. Field tests demonstrated that the ECU managed nozzle actuation for targets distributed across diverse scenarios, including spatial and temporal successions. Since the conditions on wide boom sprayers require multiple machine vision systems to actuate dozens of nozzles, an upgraded communication protocol was built at the interface of the machine vision with the ECU based on Ethernet. An application layer based on ISO 11783 was added to the CAN interface, widely used in agricultural machinery including sprayers. These upgrades allowed handling nozzle actuation at variable sprayer speeds up to 9.66 kph with a minimum spray length of 345 mm per detection, processing over 30 data frames every 40 ms. Finally, a new ISO 11783-compliant CAN bus with 60 nozzles was installed on a 36 m boom sprayer, used as a case study. This new bus featured two additional ECUs: one to communicate with other buses in the sprayer to import data like speed, and another to store pest detection and nozzle actuation data for further analysis. The case study demonstrated that a complete real-time spot application mechanism, including 30 cameras, would require an additional 4034 W for full functionality.
Open Access
VIRTUAL MENTAL HEALTH CARE FOR CHILDREN AND ADOLESCENTS: A SCOPING REVIEW OF THE LITERATURE AND EMPIRICAL EVIDENCE FROM CHILDREN AND ADOLESCENTS LIVING IN NOVA SCOTIA DURING THE COVID-19 PANDEMIC
(2025-04-30) Lang, Kaleigh; Not Applicable; Master of Science; Department of Community Health & Epidemiology; Not Applicable; n/a; Not Applicable; Dr. Debbie Emberly; Dr. Jill Hayden; Dr. Leslie Anne Campbell
This thesis aimed to identify factors influencing the implementation, delivery, and uptake of formal virtual mental health services for children and adolescents and related research gaps. A scoping review was conducted to map existing literature on virtual mental health care for children and adolescents with findings mapped using the Consolidated Framework for Implementation Research. As formal studies often exclude children and youth who do not access services, a secondary analysis was performed using data from a cross-sectional survey of youth and parents in Nova Scotia, collected between June 2021 and April 2022. Virtual care was widely implemented in response to the COVID-19 pandemic and may be a means of overcoming some barriers to care. Our findings highlight the importance of continued research to support effective and sustainable integration of virtual mental health services for children and adolescents.
Open Access
Enhancing Sustainable Crop Production: Biostimulatory Effects of Fish Hydrolysate and Nano-Sized Fish Hydrolysate on Kale and Lettuce Growth, Yield, and Phytochemical Composition
(2025-04-30) Pradeep Kumar, Anagha; No; Master of Science; Faculty of Agriculture; Not Applicable; Dr Lakshman Galagedara; No; Dr Gurpreet Singh Selopal; Dr Mumtaz Cheema; Dr Lord Abbey; Dr Svetlana Yurgel
As global food demand increases, and environmental issues become more pressing, sustainable agriculture practices are essential for improving crop output while reducing ecological effects. This study investigated the efficacy of fish hydrolysate (FH) and nano-sized fish hydrolysate (nFH) as biostimulants to enhance the growth and development of kale (Brassica oleracea var. sabellica) and lettuce (Lactuca sativa L.). Kale seeds and seedlings were subjected to FH concentrations of 0% (control), 0.25%, 0.5%, 1%, and 2% during germination and seedling growth experiments, while both crops received nFH treatment at sonication durations of 0, 15, 20, 25, and 30 mins, administered via soil drench and foliar application methods. The germination study indicated that 0.25% FH significantly increased kale germination by 15% compared to the control, resulting in an increase in root surface area. Greenhouse findings demonstrated that 2% FH boosted kale fresh weight by 43.35%, along with an increase in leaf count and photosynthetic efficiency compared to the control. In nFH, the 25-min soil drench application optimized biomass in both species, with lettuce exhibiting a 30% greater rosette diameter than the foliar treatment. Soil drench applications consistently outperformed foliar sprays, ensuring sustained nutrient delivery. Analytical techniques, such as scanning electron microscopy, validated that sonication diminished particle sizes, hence improving nutrient availability, while mineral analysis indicated elevated concentrations of key minerals, including potassium (1610 mg/L) and calcium (1410 mg/L) in FH. This study revealed that FH and nFH, especially at optimal concentrations and sonication durations, significantly enhanced plant growth and resistance, providing a sustainable method for utilizing fish waste in agriculture.
Open Access
Innovative Time-Domain Approaches for High-Performance Readout Circuits
(2025-04-30) Zareie, Mahsa; Yes; Doctor of Philosophy; Department of Electrical & Computer Engineering; Not Applicable; Dr. Rashid Rashidzadeh; Yes; Dr. Hamed Aly; Dr. Ya-Jun Pan; Dr. Kamal El-Sankary; Dr. Ezz El-Masry
The scaling of Complementary Metal-Oxide Semiconductor (CMOS) technology presents challenges for low-power, low-frequency sensor readout interfaces, particularly in nonlinearity, noise, and power efficiency. This dissertation explores time-domain signal processing (TMSP) to overcome these limitations, introducing two key contributions: a linearized open-loop Voltage-Controlled-Oscillator (VCO) Analog-to-Digital Converter (ADC) and a time-domain Goertzel-based frequency analyzer for low-frequency applications. The first contribution presents an ultra-low-power open-loop VCO-ADC, designed for direct digitization of low-frequency signals. A pseudo-differential transconductance, (G_M), stage linearization technique effectively suppresses even-order and third-order harmonics distortion, enhancing linearity and Dynamic Range (DR). Fabricated in 180 nm CMOS, the design achieves an Spurious-Free Dynamic Range (SFDR) of 81.48 dB, Total Harmonic Distortion (THD) of -76.8 dB, and Signal-to-Noise-and-Distortion Ratio (SNDR) of 70.9 dB (equivalent to 11.48 Effective Number of Bits (ENOB)) over a 3.6 kHz Bandwidth (BW), with low flicker noise achieved through a chopper-based noise suppression technique. The ADC operates at 1 V, consuming only 20.3 μW, making it highly efficient for low-frequency sensor readout. The second contribution introduces a time-domain Goertzel-based frequency analyzer, implemented for the first time in the analog time domain. A set of proposed TMSP arithmetic circuits, including a single-step time-register (TR) and time-amplifier (TA), enables real-time magnitude and phase extraction with less than 5% error for input frequencies up to 400 Hz. The CMOS 180 nm implementation consumes less than 24 μW, demonstrating superior power efficiency compared to conventional ADC + FFT architectures. These findings establish time-domain architectures as a scalable, low-power alternative for low-frequency sensor interfaces.
Open Access
EXPLORING THE ROLE OF SEX, FRAILTY, OR NEUROPATHOLOGY IN THE ANTIDEPRESSANT-ALZHEIMER’S DISEASE ASSOCIATION: A SCOPING REVIEW AND A SECONDARY DATA ANALYSIS
(2025-04-30) Eum, Lucy; Not Applicable; Master of Science; Medical Research Graduate Program; Received; Ruth Ann Marrie; Not Applicable; Sanja Stanojevic; Sultan Darvesh; Ashley Drohan; Shanna Trenaman; Melissa K Andrew
Background: Depression is a modifiable risk factor of dementia. The antidepressant-dementia association among older adults remains inconsistent. Methods: Two separate studies — a scoping review and a retrospective study — were conducted. The scoping review assessed whether sex or frailty has been studied as an effect modifier (EM) or confounder of the antidepressant-dementia relationship. The retrospective study assessed whether sex, frailty, or neuropathology modifies the antidepressant-dementia relationship. Results: The scoping review found that frailty was not explored as a confounder or EM in the literature. Sex was not explored as an EM. Studies examining sex as a confounder differed widely in their methodologies. The retrospective study found an association between antidepressant use and clinical dementia (odds ratio 2.65, 95%CI: 1.99-3.54). Male sex, frailty, and neuropathologic burden tended to have weaker antidepressant-dementia association, but this was not statistically significant. Conclusion: More studies are needed to explore potential EMs of the antidepressant-dementia relationship.
Embargo
ENERGY TRANSITION IN SMALL COMMUNITIES UNDER UNCERTAINTY
(2025-04-30) Mostafavi Sani, Mostafa; No; Doctor of Philosophy; Department of Industrial Engineering; Not Applicable; Fuzhan Nasiri; No; Uday Venkatadri; Michelle Adams; Hamid Afshari; Ahmed Saif
Transitioning small and remote communities to renewable energy is critical for achieving global net-zero targets. These communities, reliant on costly and emission-intensive fossil fuel systems, require tailored renewable energy frameworks and robust planning strategies to ensure reliable, sustainable, and cost-effective energy solutions. This dissertation addresses these needs through two interconnected themes: designing renewable energy systems specifically suited to local conditions and strategically planning transitions to net zero under uncertainty. In the first theme, advanced optimization models are developed to assess hydrogen's potential as seasonal energy storage, aligning social, economic, and environmental objectives. Results demonstrate significant potential for hydrogen to enhance energy reliability, reduce fossil fuel dependence, and support sustainability. By 2050, strategic deployment of hydrogen and wind power is expected to double capacity, substantially decreasing reliance on external grid connections. Further analyses cluster remote Canadian communities based on resources, climate conditions, and energy demand patterns, revealing hydrogen storage's effectiveness in mitigating seasonal energy fluctuations. Acknowledging the critical role of uncertainties in renewable energy transitions, the second theme introduces multi-stage stochastic robust optimization techniques to handle short-term energy variability and long-term uncertainties such as technology cost developments and evolving carbon policies. The findings highlight that phased investment strategies considerably outperform single-phase transitions, enhancing economic and environmental outcomes. Additionally, assessing the feasibility of waste-to-energy technologies alongside other renewable energy systems is crucial for boosting overall system reliability. Specifically, pyrolysis emerges as an adaptable, cost-effective solution, significantly lowering hydrogen production costs and effectively integrating waste management with broader renewable energy strategies. The thesis delivers frameworks for informed, resilient, and efficient renewable energy transitions in small, remote communities.
Open Access
Disrupting Carceral Pathways: Experiences of Anti-Youth Ageism and Criminalization in Canadian Child Welfare
(2025-04-30) Amirault, Bryn; Not Applicable; Master of Social Work; School of Social Work; Received; Dr. Brooke Richardson; No; Dr. Michael Ungar; Dr. Nancy Ross
The Canadian child welfare system currently faces a significant issue: youth in care are disproportionately represented in the criminal justice system, a phenomenon known as the care-to-prison pipeline. Quantitative macro-level factors have been well established. What remains underexplored are the micro-level dynamics within group care facilities that may facilitate anti-youth ageism and perpetuate criminalization. Using a qualitative phenomenological design and an intersectional feminist theoretical lens, this research draws on the lived experiences of five former youth in care. In particular, it examines whether anti-youth ageism is present, how intersecting identities impact experiences, and how these factors facilitate criminalization. Ultimately, this study provides a platform for the voices silenced by child welfare to tell their stories and share tactics to disrupt carceral pathways for youth in care.
Open Access
Effect of Hydrogen Absorbent Material in Conductive Coating ICCP System
(2025-04-29) Kashani, Kousha; Not Applicable; Master of Applied Science; Department of Mechanical Engineering; Not Applicable; Dr. Hany El Naggar; Not Applicable; Dr. Zoheir Farhat; Dr. George Jarjoura
Although cathodic protection is widely used for corrosion mitigation, it faces limitations, particularly in protecting parts intermittently exposed to water or shielded from anodes. In complex structures like marine vessels or steel frameworks, traditional systems often fail to protect submerged, buried, or elevated areas effectively. Conductive Coating ICCP (Impressed Current Cathodic Protection) systems address these issues by applying an anode directly onto the substrate surface, reducing power demands, minimizing stray current corrosion, and lowering installation costs. However, overprotection in such systems can cause hydrogen gas evolution at the cathode, leading to blistering and filiform corrosion. This research aims to mitigate hydrogen-related damage by identifying a suitable hydrogen absorbent material and compatible catalyst, optimizing their proportions, and incorporating them into the coating. Performance is evaluated through controlled hydrogen absorption tests, with the ultimate goal of enhancing the long-term durability and effectiveness of Conductive Coating ICCP systems.
Embargo
Exploring the Application of Plasmonic Group IV Transition Metal Nitrides via Surface Modification Strategies
(2025-04-30) Shea, Dreenan Anne; Yes; Doctor of Philosophy; Department of Chemistry; Not Applicable; Dr. Christa Brosseau; Not Applicable; Dr. Peng Zhang; Dr. Norman Schepp; Dr. Ghada Koleilat; Dr. Mita Dasog
The interest in plasmonic transition metal nitrides (TMNs) has expanded recently due to the chemical and thermal stability of their bulk counterparts. While their popularity has grown, the chemical properties of nano-sized TMNs have remained unexplored. As chemical properties such as stability dictate the feasibility of TMNs, this doctoral work first analyzes pH and oxidative stability of these nanomaterials. Amongst investigation via UV-Vis spectroscopy, TiN experienced complete oxidation in 60 days, while ZrN and HfN remained relatively stable. However, all three TMNs showed stable pH ranges of 2-3, observed via zeta potential measurements. Dispersibility studies of TMN nanoparticles showed water as the only functional solvent. The focus of this thesis is stability enhancement of group 4 TMNs (TiN, ZrN and HfN) using surface modification techniques. For surface functionalization studies, multiple silanes (APTES, dimethyldichlorosilane, mPEG-silane) were used as coupling agents due to their reactivity with hydroxy-terminated oxide shells on TMN surfaces.
Open Access
Framing Community Responses to Environmental Disasters: A Case Study of Media Coverage of the Wakashio oil spill in Mauritius
(2025-04-29) Nombro, Emily; Not Applicable; Master of Arts; Department of International Development Studies; Received; n/a; Not Applicable; Dr. John Cameron; Dr. Theresa Ulicki; Dr. Matthew Schnurr
On July 25th, 2020, the MV Wakashio ran aground on the southeastern coral reefs of Mauritius, spilling around one thousand metric tonnes of oil into the sea. The disaster received widespread local and international media coverage, covering both government and civil society response efforts. News media play a significant role in shaping narratives during disasters through frames, influencing public perception of the different response actors. Previous research has demonstrated that both local and international news media can frame the same disaster differently, often reinforcing dominant Western narratives. This thesis uses the Wakashio oil spill to investigate how local versus international news agencies framed the government and civil society responses. Findings show that the local news agencies offered more detailed commentary and critique, particularly of the government response, and, contrary to the literature, the international coverage of the disasters was positive. Finally, implications for future disaster policy and planning are discussed.
Open Access
Easyfeed: A Persuasive Breastfeeding Application for Nigerian Women
(2025-04-27) Chimamaka , Eneze; Not Applicable; Master of Computer Science; Faculty of Computer Science; Received; N/A; Not Applicable; Bonnie MacKay; Oladapo Oyebode; Rita Orji
Persuasive Technologies (PTs) are widely used as applications for promoting healthy behavior changes. They are applied in and tailored to many domains, including maternity and childcare. PTs incorporate different strategies capable of promoting this behavior change, including self-monitoring. Most current breastfeeding applications focus on Western culture, with little consideration for the cultural nuances and unique experiences of Nigerian breastfeeding mothers. Thus, this thesis seeks to address this gap by developing a breastfeeding application that is culturally relevant and tailored to the Nigerian community. We present the design, development, and evaluation of the Easyfeed application, a mobile health (mHealth) application for promoting breastfeeding practices among Nigerian mothers. Through exploratory research, combining user-centered design (UCD) and persuasive systems design approaches, we designed the application and conducted a two-phase study (Easyfeed Phase 1 and Easyfeed Phase 2) to evaluate: the effectiveness of different persuasive strategies employed, usability, impact on breastfeeding mothers' motivation, attitudes, self-efficacy, and Nigerian mothers’ health belief inclinations. Prior to Phase 1, we identified three design goals (DG) from reviewing gaps in existing literature on mHealth applications for breastfeeding mothers: DG1 – Enhancing cultural relevance through shared design for Nigerian mothers and the inclusion of cultural music, DG2 – Implementing evidence-based persuasive strategies to encourage continued breastfeeding, and DG3 – Incorporating breast milk pumping to motivate breastfeeding. In Phase 1, we developed a medium-fidelity prototype of the Easyfeed application addressing DGs 1-3 while incorporating three persuasive strategies (self-monitoring, reminder, and reward), that were selected based on existing applications, aligning with our design goals. We surveyed 154 participants to gather feedback on the prototype's usability, effectiveness, motivation to breastfeed, and its cultural relevance. The results from this survey helped to identify areas for improvement and informed the next phase of development, ensuring that the application was more tailored to users' needs and preferences. Subsequently, we invited our participants to take part in a voluntary interview session where 14 Nigerian women were interviewed to understand their overall perceptions about the application. Our analysis revealed several features that needed to be refined for Easyfeed Phase 2, including music and journaling. Finally, in Phase 2, we refined the Easyfeed application based on feedback from Phase 1 and developed a high-fidelity prototype, incorporating additional persuasive strategies (competition and emotional appeal). The Phase 2 evaluation (N = 75) in the wild for 10 days, followed by an optional one-on-one interview with 15 participants, showed that the Easyfeed application was perceived as highly motivational, persuasive, useful, and supportive of their breastfeeding journey.
Open Access
Staffing Models for Blood Donation Centres: A Model-Driven Approach
(2025-04-29) Leeshanok, Emma; Not Applicable; Master of Applied Science; Department of Industrial Engineering; Not Applicable; N/A; Not Applicable; Peter Vanberkel; Leslie Ann Campbell; John Blake
Building on the work conducted by Blake & Shimla (2014), the model presented by this project generates staff schedules based on the minimum staffing requirements for donation clinics operated by Canadian Blood Services (CBS). The proposed design is comprised of two integer programming models and uses a simplified column generation algorithm. Based on the targets set by the user, the first model selects an optimal configuration of clinic length and bed count. These values are then fed into the second model, which assigns shifts based on the calculated requirements. When compared to schedules generated by the client, the model was able to produce solutions of similar or higher quality while also minimizing the operational costs of the clinics. Beyond optimizing clinic scheduling for CBS, this framework can be adapted and applied to other areas within the healthcare industry.
Embargo
THE METABOLIC DISORDER OF ALZHEIMER’S DISEASE IN THE 5XFAD MOUSE MODEL AND HOW INSULIN AND GHRELIN CAN BE USED AS THERAPEUTICS
(2025-04-29) Gendron, William; Yes; Doctor of Philosophy; Department of Psychology and Neuroscience; Received; Dr. Alfonso Abizaid; Yes; Dr. tara Perrot; Dr. Shelley Adamo; Dr. Richard E. Brown; Dr. Younes Anini
A subset of patients with Alzheimer’s disease exhibit involuntary age-related weight loss not related to failure to eat. This weight loss can reduce the quality of life, increase frailty, and mortality. The 5xFAD mouse model of AD also exhibits this phenotype. Consequently, we evaluated the metabolic factors underlying age-related weight loss in the 5xFAD mouse model. Male and female 5xFAD mice tested in metabolic cages (Experiment 1) at 12 months of age showed metabolic abnormalities compared to WT mice (B6SJLF2/J) that were sex specific. Both male and female 5xFAD mice exhibited weight loss, fat loss, and lean mass loss, and in males this was driven by a hypermetabolic system. However, in females this weight loss was driven by a hypometabolic system that impaired activity, feeding behaviour, and fat production. To attenuate this loss in weight and body fat we injected the 5xFAD mice with the orexigenic hormone ghrelin (Experiment 2). Ghrelin attenuated weight loss and increased food intake in all mice with the exception of male 5xFAD mice. Ghrelin also improved spatial memory in all mice except the 5xFAD males. An increase in fat storage did not occur after ghrelin injections. Rather, ghrelin administration reduced WAT amounts. Along with metabolic impairments in the body, both AD patients and 5xFAD mice exhibit metabolic impairments in the brain such as reduced glucose metabolism. We therefore infused insulin intransally as a means to enhance insulin signalling via enhancing the activation of the PI3K-Akt pathway (Experiment 3). Insulin infusions increased Akt activation, improved spatial memory, muscle strength, and reduced frailty without inducing hypoglycemia. Both insulin and ghrelin injections reduced freezing behaviour in the 5xFAD mice suggesting that these hormones may have anxiolytic properties. The results of these studies indicate that the 5xFAD mice exhibit metabolic impairments in the brain and body and the nature of this metabolic impairment is dependent on sex. While ghrelin administration attenuated weight loss it did not increase adiposity suggesting that a different route of injection, e.g. intranasal, or drug, e.g. corticosteroids, may be an effective way to induce fat storage. Intra-nasal insulin enhanced the activation of the PI3K-Akt pathway thereby improving spatial memory and reducing frailty. These studies support the hypothesis that AD is a metabolic disorder of the brain and body and indicate that the symptoms of this disorder may be partially reversed by hormones such as insulin and ghrelin that enhance Akt signalling and prevent weight loss.
Open Access
What’s that Smell?: Thermally Modulated Machine Olfaction by Joule Heating to Detect And Identify Odourant Molecules
(2025-04-28) Murdoch, Lynne; Yes; Master of Science; Department of Chemistry; Not Applicable; NA; No; Heather Andreas; Khaled Benis; Michael Freund
The olfactory sense is one of the first evolved by early life. Mimicking olfaction through artificial systems provides a crucial understanding of the world and surroundings. The field of machine olfaction aims to achieve just this goal. In this work, the use of a thermally modulated, chemically diverse carbon black-polymer composite sensor array is shown to be able to identify and quantify a variety of odourant analytes. As mammalian olfaction relies on sniffing to maintain a constant response within the brain, so too does thermal modulation provide a drift-resistant peak-to-peak response. Through the sorption and desorption of analyte, the connectivity within the composite will change, causing percolation network-driven changes in resistance, allowing for quantification. The degree of resistive change between exposures of various analytes is unique, providing a fingerprint-like response from an array of sensors. This work demonstrates that both analyte concentration and identity are captured by modulated signal amplitude.
Open Access
A Framework for Detecting and Mitigating DDoS Attacks in Software-Defined IoT Networks
(2025-04-29) Sun, Pengxiang; Not Applicable; Master of Computer Science; Faculty of Computer Science; Not Applicable; NA; Not Applicable; Dr.Yujie Tang; Dr.Darshana Upadhyay; Dr.Srinivas Sampalli
The integration of Internet of Things (IoT) technology and Software-Defined Networking (SDN) into Software-Defined IoT (SD-IoT) creates new opportunities while introducing significant security challenges. An emerging area of research is the detection and mitigation of DDoS attack on SD-IoT networks. Many existing DDoS intrusion detection methods rely on outdated datasets. This thesis presents a framework for DDoS detection and mitigation in SD-IoT. A novel approach is introduced for extracting informative features from network traffic and generating datasets. In the detection phase, generated datasets are used to train machine learning models for DDoS detection. For mitigation, a strategy combining micro-segmentation with Attribute-Based Access Control (ABAC) is proposed, enabling effective attack containment and establishing a robust defense-in-depth framework. The results demonstrate the importance of the extracted features in training machine learning models for DDoS detection. A use case further illustrates the efficiency of the proposed micro-segmentation method in mitigating DDoS attacks.
Open Access
DISTRIBUTION OF MICROCOLEUS AND ANATOXINS IN KJI-QOSPEM, SHUBENACADIE GRAND LAKE
(2024-04-28) Morris, Hannah; Not Applicable; Master of Applied Science; Department of Civil and Resource Engineering; Not Applicable; Janice Lawrence; Not Applicable; Barret Kurylyk; Rob Jamieson; Daniel Beach
In the spring of 2021, two dogs died after ingesting suspected benthic cyanobacterial mats along the shoreline of Kji-Qospem lake, commonly known as Shubenacadie-Grand, a large oligotrophic lake, in Nova Scotia. Toxin producing Microcoleus spp. were identified as the cause, and initial studies indicated the mats originated from a highly impacted tributary. The central objective of this thesis was to assess how widely distributed Microcoleus is throughout the lake system using a variety of analysis. Results from a two-year sampling program revealed that toxin-producing Microcoleus was present at several locations throughout the lake, although distinct cyanobacterial mats were only observed within the stream and lakeshore area where the dog deaths occurred. These findings add to a growing body of evidence demonstrating the wide distribution of Microcoleus within Atlantic Canadian surface waters.
Open Access
Analyzing and Ranking Player Behaviours in RoboCup Soccer Simulation 2D Using Machine Learning Approaches
(2025-04-29) Amini, Omid; Not Applicable; Master of Computer Science; Faculty of Computer Science; Not Applicable; n/a; Not Applicable; Dr. Vlado Keselj; Dr. Garnett Wilson; Dr. Malcolm Heywood
This thesis investigates how advanced machine-learning techniques can rank and compare player behaviours in RoboCup Soccer Simulation 2D (SS2D), surpassing traditional metrics such as goals and assists. We fused official RoboCup logs with large-scale simulated matches to build robust data sets. Then, we used Variational Auto-Encoders and Transformers to compress high-dimensional state–action sequences into low-dimensional embeddings that preserve essential spatio-temporal patterns. We applied Maximum-Entropy Inverse Reinforcement Learning to uncover each player’s reward function, producing context-aware scores that capture both on-ball and off-ball actions. A complementary win-probability learner (“WinGain”) linked individual actions to match success. We tested framework robustness across various match conditions (communication bans, player swaps and formation changes). Our framework uncovers effective behaviours overlooked by raw statistics, enables objective cross-player rankings, and provides a data-centric foundation for optimizing strategies in SS2D and other complex multi-agent sports domains, which can aid coaches, scouts and AI researchers in evidence-based decision-making.
Embargo
Advancing Air Pollution Monitoring Assessment in Eastern Canada with Emerging Methods
(2025-04-28) Tsz Kin, Siu; Not Applicable; Master of Science; Department of Earth and Environmental Sciences; Not Applicable; Dr. Amanda Giang; Yes; Dr. Rachel Chang; Dr. Christopher Greene; Dr. Kelvin Fong; Dr. Daniel Rainham
Surface air pollution monitoring networks in eastern Canada, including Ontario, Quebec, and the Atlantic provinces, have limited coverage and high deployment and maintenance costs. The Quebec City-Windsor corridor is Canada’s most densely populated region with the highest traffic and industrial activities, while the Atlantic provinces have high population proportions of vulnerable people. Without adequate monitoring, the exposure and population health risk assessment of air pollution lacks precision. New measurement technologies and methods enable high-resolution monitoring in under-monitored communities. Low-cost air quality sensors enhance the density of surface monitoring. This study assessed the spatial distributions of low-cost sensors and regulatory monitoring stations for fine particulate matter (PM2.5) in eastern Canada with locally adaptive kernel density estimation (KDE), and found persistent monitoring gaps and disparities in monitoring coverage in communities with social deprivation. A new remote sensing satellite instrument, Tropospheric Emissions: Monitoring of Pollution (TEMPO), provides raster observations of tropospheric column nitrogen dioxide (NO2) on a daytime hourly basis. Examining its high spatiotemporal resolution data, this study identified previously unrecognized NO2 hotspots, monitoring gaps in eight highly polluted and densely populated municipalities, and variations in temporal NO2 patterns. Linking the remote sensing to in-situ surface-level observations, with ancillary data of meteorology, land use, land cover, and urban environment, this study applied land use regression and hotspot mapping for air pollution monitoring gap assessment in a hyperlocal context. Saint John, New Brunswick, an industrial city with sulphur dioxide (SO2) pollution, was selected as a case study for intra-urban pollutant modelling. In summary, this thesis highlights current air pollution monitoring gaps in eastern Canada and informs future policy planning in monitoring expansion, resource management, and health surveillance in under-monitored communities. It also demonstrates the use of novel geospatial data and methods in studying air pollution and motivates future research.
Embargo
Ligand Design and Reactivity of Pnictogen Pincer Complexes
(2025-04-24) Kirsch, Tamina; Yes; Master of Science; Department of Chemistry; Not Applicable; n/a; Yes; Charles Macdonald; Alex Veinot; Saurabh S. Chitnis
This thesis discusses the design of ligands as a tool to modify the reactivity of planar pnictogen pincer complexes. Computational and experimental methods were explored with the goal of deepening our understanding of the unique interplay of the ligand and the central pnictogen. A theoretical study of 64 different pnictogen pincer complexes explored the impact of the ligand framework on the steric and electronic properties of pincer complexes and revealed trends which help explain the reactivity of pnictogen-based pincer ligands. A new class of sterically demanding NCN pincer ligands featuring benzylic methyl groups was developed which provides valuable insights into the properties of such bulky ligand systems. The findings of this thesis deepen our understanding of pnictogen pincer complexes. They help not only to explain the reactivity of known compounds, but also to predict reactivity of unknown complexes, thus identifying potential complexes as future targets.
Open Access
Improved Validation of Earth System Models
(2025-04-28) O'Connell, Ethan; Not Applicable; Master of Science; Department of Mathematics & Statistics - Statistics Division; Not Applicable; n/a; Not Applicable; Orla Murphy; Bruce Smith; Mike Dowd
Earth system models are numerical models that simulate the physical dynamics of the atmosphere and the oceans, as well as other chemical and biological processes. With increases in computational power and model complexity, there is an increased need for performance assessment to better inform decision making. In this thesis, we provide an overview of common statistical methods and develop new approaches for the validation of Earth system models, with a focus on application-specific validation metrics. We apply these methods to the simulation of nearshore ocean temperatures along the Atlantic coast of Nova Scotia, emphasizing techniques for the evaluation of short-term variability and extremes. To assess the effectiveness of these approaches across various types of numerical models, we compare two iterations of a regional FVCOM model, the GLORYS12v1 reanalysis dataset, and a representative CMIP6 model against temperature observations at two nearshore study sites.