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Task Management Optimization in Vehicular Edge Computing
No full textVehicular Edge Computing (VEC) is a specialized extension of Mobile Edge Computing (MEC) designed to support real-time processing in intelligent transportation systems. It enables vehicles to offload computationally intensive tasks to nearby Roadside Unit (RSU)s equipped with MEC servers, reducing latency for time-critical applications such as autonomous driving, intelligent traffic control, and Vehicle-to-Everything (V2X) communication. However, the mobility of vehicles and the short coverage duration within an RSU’s range present significant challenges for task offloading and scheduling. The growing volume of tasks from multiple vehicles can cause congestion, delays, and task drops, undermining overall system performance. To establish a performance benchmark, we first employ deterministic algorithms, including First-Come, First-Served (FCFS) and Shortest Deadline First (SDF), which are simple and fast methods for real-time task offloading. To explore more efficient scheduling, we then apply a metaheuristic method called Particle Swarm Optimization (PSO). This optimization approach is first evaluated in a static scheduling environment, in which the algorithm is executed only once on all tasks, without considering their real-time arrivals, and schedules them all at once. FCFS executes tasks in arrival order without prioritization, while SDF improves performance by prioritizing tasks with shorter deadlines. PSO achieves the best performance in this static environment because execution time and additional waiting times caused by the static nature are ignored. This method is called Offline Static PSO (Off-Sta-PSO), and it provides the theoretical upper bound. By considering the real-time execution and waiting times introduced in this scenario, we also establish the lower bound case, called Online Static PSO (On-Sta-PSO), which yields the worst performance. Recognizing the limitations of task offloading, we also propose a task partitioning approach. Some portions of the tasks are offloaded to RSUs, while the remaining parts are processed locally by onboard vehicle processors, leading to reduced latency and fewer dropped tasks. Moving to real-time task offloading, while dynamic PSO enhances task scheduling, its high computational cost and long convergence times limit its real-time viability. To address this, we introduce Online Dynamic Cost-Driven Algorithm (On-Dyn-CDA), a novel real-time scheduling algorithm. Unlike PSO, it operates in milliseconds, adapts to vehicle mobility, congestion, and RSU load, and requires no pre-training. On-Dyn-CDA surpasses Dynamic PSO by 3.42% in task loss, reduces latency by 29.22%, and executes in just 0.05 seconds under the most complex scenario, compared to 1330.05 seconds required by Dynamic PSO. Finally, we compare online PSO with Deep Reinforcement Learning (DRL) methods like Deep Q-Network (DQN) and proximal policy optimization (PPO). Although Reinforcement Learning (RL) is grounded in the Markov Decision Process (MDP), which assumes a stationary environment, VEC systems are inherently dynamic due to vehicle mobility, changing task arrivals, and variable RSU associations. To address this mismatch, our framework introduces a decision window mechanism that segments incoming tasks into locally stable intervals, allowing the RL agent to operate under near-stationary conditions. Additionally, we design adaptive reward functions that guide the agent to minimize both task drops and end-to-end (E2E) latency, based on real-time task characteristics and server availability. The state space includes dynamic context such as MEC server availability and task deadlines, enabling informed and responsive decision-making. Our DQN and PPO models are trained on diverse mobility traces and evaluated in unseen environments, demonstrating strong generalization without retraining. Despite the non-stationarity of VEC, this design enables robust online scheduling, with DQN outperforming dynamic PSO in both latency and task reliability. DQN substantially reduces execution time, completing in only 10.62 seconds, lowers dropped tasks by 2.5%, and decreases E2E latency by 18.6%. Compared to PPO, DQN achieves a 57.1% reduction in execution time, along with a 5.7% decrease in E2E latency and a 1.7% reduction in dropped tasks. The results demonstrate the effectiveness of this research in addressing the core challenge of real-time task scheduling in VEC systems
The Effects of Cold Exposure and Energy Deficit on Energy Balance
No full textThe main objective of this thesis was to examine the effects of cold exposure (CE) on energy intake (EI), energy expenditure (EE), hunger, and body weight in individuals living with obesity and determine its feasibility as a weight loss tool. The first article reviewed the current state of the literature, highlighted the gaps in knowledge surrounding individuals living with obesity and EI in CE research, and identified the research questions to be addressed. The second article examined the effects of acute CE on energy balance, hunger, and thermoregulatory outcomes. CE caused both EI and EE to increase, but the magnitude of both changes was quite small while having no impact of appetite. Skin temperature, peptides, thermal comfort and thermal sensation all demonstrated that the CE stimulus was potent, but EE only increased by an average of 20.3±20.6 kcal over 90 minutes, a mere 12% of what lean individuals undergoing the same stimulus would
experience. The third article examined the effects of three 8-week weight loss interventions on energy balance, body weight and appetite: a dietary restriction of 30% (DIET), 28 cold sessions (CE), or both stimuli together (DIET+CE). CE alone did not result in weight loss or significantly improve weight loss outcomes when combined with a dietary restriction. EE increased for all three groups post intervention, thermal sensation improved post intervention for all groups, and subjective appetite changed between the three groups. EI and skin temperature did not change significantly post intervention. For the first time, CE was shown to not significantly improve weight loss outcomes alone or when used in
combination with a dietary restriction. High levels of thermal discomfort, minimal increases in heat production during CE, and high dropout rates highlight the challenges in feasibility of using CE as a weight loss adjunct
Data-Based Decision Making in Online Secondary Courses: A Multi-Level Examination of Practices, Determinants, and Needs.
No full textData-based decision-making (DBDM) has become a cornerstone of educational policy and practice, aiming to enhance student learning through conducting informed instructional and pedagogical decisions (Curry et al., 2016; Hebbecker et al., 2022; Peters et al., 2021; van der Scheer et al., 2016). By leveraging various forms of student data, such as assessment results, engagement metrics, and learning analytics, educators are expected to tailor instruction, identify struggling students, and improve overall academic outcomes (Faber et al., 2018; Voithofer & Golan, 2019). However, despite its potential, the effective implementation of DBDM remains inconsistent, particularly in secondary and online education, where research is limited. This thesis, structured as a series of three articles, explores global trends in teacher engagement with DBDM, the factors shaping its use among Ontario secondary school teachers in online courses, and the professional learning opportunities needed to strengthen their DBDM practices.
The first article presents a scoping review of international research on teacher DBDM, which reveals geographical and temporal patterns and highlights gaps in secondary and online education, underscoring the need for more sustainable DBDM support. The second article is a mixed methods study that investigates Ontario secondary teachers’ engagement with DBDM in online courses and identifies key influencing factors such as collaboration, leadership, data quality, and teacher efficacy. The findings suggest that while collaboration and efficacy promote data use, concerns regarding data accessibility and DBDM-related anxiety pose barriers to effective DBDM use. The third article investigates Ontario secondary teachers’ needs to be able to use data effectively by examining gaps in their data competencies and proposes targeted professional learning opportunities. Findings emphasize the necessity of training in AI-driven analytics, subject-specific DBDM applications, and scenario-based learning to support teachers in effectively integrating data into their instructional practices.
Together, these studies contribute to a deeper understanding of teacher engagement with DBDM and offer empirical insights into the landscape that shape data use in education. By examining both enablers and barriers to data use within the online teaching environment, this research provides actionable recommendations for professional development, and future research to enhance data-informed teaching and improve student outcomes
Examining differences in exposure to digital marketing of unhealthy foods reported by Canadian children and adolescents in two policy environments
No full textAbstract Background There has been relatively little research on youth’s exposure to food marketing on digital media, which is important as new digital platforms emerge and youth spend more time online. Evidence evaluating different policy approaches to restricting digital food marketing to children is also limited. This study examined differences in self-reported exposure to digital food marketing between children and adolescents in different policy environments: Ontario (where food marketing is self-regulated) and Quebec (where advertising is government regulated). Methods An observational cross-sectional online survey was conducted in April 2023 among children (aged 10–12 years) and adolescents (13–17 years) from Ontario and Quebec, recruited by Leger Marketing. Participants self-reported their frequency of exposure to food marketing via various digital platforms and marketing techniques. Logistic regression and proportional odds models examined differences in exposure by province and age group, adjusting for sociodemographic characteristics and digital device usage. Results The odds of reporting more frequent exposure to marketing of sugary drinks (OR: 0.48; 95% CI: 0.33, 0.69), sugary cereals (OR: 0.59; 95% CI: 0.41, 0.86), salty/savoury snacks (OR: 0.67; 95% CI: 0.47, 0.96), fast food (OR: 0.65; 95% CI: 0.45, 0.92), and desserts/sweet treats (OR: 0.54; 95% CI: 0.37, 0.78) were lower among Quebec children than Ontario children. Quebec children were less likely than Ontario children (OR: 0.56; 95% CI: 0.38, 0.84), but more likely than Quebec adolescents (OR: 1.58; 95% CI: 1.04, 2.42), to report exposure to unhealthy food marketing on one or more gaming/TV/music streaming platform/website(s). Compared with Ontario children, Quebec children were less likely to report exposure to marketing featuring characters or child/teenage actors (OR: 0.51; 95% CI: 0.34, 0.76), child-appealing subjects, themes and language (OR: 0.59; 95% CI: 0.40, 0.89), and visual design, audio and special effects (OR: 0.64; 95% CI: 0.41, 0.99), and to report exposure to a greater number of marketing techniques (OR: 0.60; 95% CI: 0.43, 0.84). Conclusions Exposure to unhealthy food marketing on digital media is high for youth from Ontario and Quebec, particularly for Ontario children. These findings reinforce the need for federal regulations to protect Canadian youth from unhealthy food marketing on digital media
To Wield Education: An Analysis of the Liberation Front of Mozambique's Interpretation of Education (1962-1980's)
No full textThis thesis examines how the Liberation Front of Mozambique (Frelimo), the ruling party of independent Mozambique, perceived education as a political tool used to challenge colonial myths and bolster support for the party. During the Liberation War (1964-1974) Frelimo created educational programs for African youth; these programs were the inspiration for the post- independence educational school system, utilized to promote a shared sense of national identity tied to the party. Frelimo understood education as a tool to promote and police identities, frequently encouraging youth and adults alike to prioritize education within their daily lives. Through a national education system, Frelimo aimed to maintain and strengthen the leadership they achieved upon independence.
Education is often associated with building and supporting national identities; however, historians have often analyzed the political use of education through the examination of educational policies. This thesis offers an alternative lens, focusing on Frelimo’s discourse towards education, centering on how Frelimo situated education within their wider political agenda. Simultaneously, addressing how Frelimo intended for people to engage with education to inform their identity and relationship with the state. By taking a political and cultural historical approach, this thesis sets out to identify how Frelimo approached education as a tool to strengthen their political leadership and used exclusionary processes that enforce a singular perspective of citizenship
Physiological Insights Into a Novel Anaerobic Hg(II) Reduction Pathway in Anoxygenic Phototrophs
No full textMercury (Hg) is a pollutant of global concern and a potent neurotoxin that bioaccumulates and biomagnifies in terrestrial and aquatic food webs as methylmercury (MeHg). Though now heavily regulated, over a century of legacy anthropogenic emissions and releases of Hg into the environment still affect us today. Anaerobic microorganisms are principally responsible for producing MeHg from new and legacy pollution, a process which depends on the bioavailability of inorganic Hg. Hg redox reactions, such as HgII reduction to gaseous elemental Hg0, play a key role in determining the availability of Hg in the environment. In anoxic environments, certain anaerobic and phototrophic microbes can catalyze the reduction of HgII and may compete for other vital resources and nutrients with Hg methylators. Currently, the physiological mechanisms driving this anaerobic redox reaction are poorly understood. The main objective of my thesis is to uncover physiological and environmental controls of anaerobic and phototrophic HgII reduction pathways. I used a combination of microbial physiology, molecular biology, and trace Hg analytical techniques to study HgII reduction by anoxygenic phototrophs and fermenters from the Heliobacteria family. In Chapter 2, I discovered a novel HgII-reducing Heliobacteria from rice paddies. The magnitude of HgII reduced was enhanced by assimilating reduced sulphur sources, leading us to propose that anabolic pathways that consume reducing power can influence HgII reduction. In Chapter 3, I investigated the influence of nitrogen availability and metabolism on the magnitude of HgII reduction. Here, contrary to sulphur assimilation, nitrogen did not influence the magnitude of HgII reduced. In Chapter 4, I demonstrated how the ability to reduce HgII is tied to phototrophic and fermentative reducing power-generating machinery. In Chapter 5, I showed that HgII reduction depends on interactions between Hg and cellular thiols. Lastly, in Chapter 6, I explored the possibility of HgII reduction in phylogenetically distant anoxygenic phototrophs from the Chloroflexota phylum. At its core, my thesis underscores the relationships between HgII reduction and cellular pathways that produce or consume reducing power. Though still unresolved, my thesis significantly contributes to uncovering the cellular mechanism catalyzing anaerobic HgII reduction
Explorer le sentiment d’appartenance à la culture franco-ontarienne chez des élèves immigrants fréquentant les écoles francophones
No full textL’immigration contribue significativement à la croissance démographique et à la diversité culturelle du Canada. Le ministère de l’Éducation de l’Ontario, pour soutenir les élèves immigrants dans les écoles francophones, propose des programmes de francisation. Toutefois, on remarque que les politiques valorisant la francophonie visent surtout la culture franco-ontarienne. Cette thèse, via l’approche écosystémique de Bronfenbrenner et la collaboration école-famille-communauté, cherche s’il est possible pour les élèves immigrants et leur famille fréquentant ces écoles de développer un sentiment d’appartenance à la culture franco-ontarienne. Réalisée dans une école primaire d’Ottawa, notre recherche qualificative à posture descriptive a utilisé un échantillon (n=6) aléatoire d’élèves de la 4e à la 6e année pour remplir un questionnaire autoadministré en ligne et participer à un groupe de discussion semi-dirigé. Nos résultats suggèrent que les élèves développent un sentiment d’appartenance, mais il faut valoriser leur bagage culturel, inclure les parents à l’école, et collaborer avec les associations communautaires
Characterization and Vaccine Strategy Development for Circulating and Emerging Respiratory Viruses
No full textThe ongoing evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the emergence of highly transmissible variants of this virus have significantly impacted the effectiveness of vaccines against infection, COVID-19 disease outcomes, and transmission. The decline in vaccine efficacy can be attributed to several factors, including immune evasion by new variants, waning immunity over time post-vaccination or infection-acquired immunity, and inadequate induction of protective mucosal immunity. While booster vaccinations have notably enhanced protection against severe disease, the continuous evolution of the virus necessitates a re-evaluation of current vaccine strategies due to their inherent limitations to prevent new infections.
To address these challenges effectively, it is crucial to consider the viral life cycle, accurately characterize viral phenotypes, and understand the interactions between the virus and the host, as well as the resulting immunological responses. This thesis explores virus-host interactions by characterizing viral phenotypes using flow virometry techniques and investigates viral kinetics, alongside the modulation of the host's immune response following viral infection. By analyzing these interactions, we aim to refine vaccine design and delivery, advancing the development of next-generation vaccines against SARS-CoV-2 and other respiratory viruses.
This doctoral thesis examines different immunization regimens and vaccine formulations, characterizing the humoral responses across various anatomical and immunological compartments. My research identifies immunogenic targets for intranasal vaccine design against SARS-CoV-2 and explores the impact of different vaccine formulations on induced humoral responses, providing insight into the development of a universal vaccine platform. Robust and durable mucosal immunity is crucial for neutralizing viruses and limiting infection at the point of entry. Lastly, a plant-based expression platform for producing vaccine antigen candidates was evaluated, highlighting plant-produced proteins as advantageous candidates for use in protein subunit vaccines. Our data supports that the mucosal humoral response to SARS-CoV-2 intranasal vaccination is relevant to the development of more effective next-generation vaccine strategies to combat SARS-CoV-2 and other respiratory pathogens
Master of Thy Fate? : The Role of Prior Success in Shaping Children's Illusory Control and Reliance on Informants in Novel Situations
No full textWith increased access to information, children are required to filter information more frequently than ever. Although previous research has examined how children use the characteristics of others (e.g., such as confidence) to selectively learn, little is known about the role of children's own characteristics in selective learning. My thesis examines individual differences in children's illusory control, or overconfidence in their abilities, and its influence on their decision to engage in social learning. The Pilot Study aimed to develop a task to manipulate children's illusory control and assess its subsequent impact on their help requests towards an accurate informant. Based on pilot results, methodological changes were made for the next two studies. In Study 1, 5-year-olds first experienced success or failure at locating objects to manipulate their illusory control. Next, they chose whether to answer novel questions by themselves or with the help of a knowledgeable informant. In Study 2, 7- and 8-year-olds experienced the same manipulation and then answered novel questions, endorsing or omitting a teacher and search engine answers. Afterward, more novel questions were presented where children chose to answer on their own or with the help of one of the informants. Results revealed that children's prior success influenced their decision to trust the informants but only in the same domain as when they experienced their success or failure. On average, younger and older children requested help for half the questions. Overall, children did not demonstrate a preference for the teacher or the search engine; however, their choice was influenced by the success manipulation, the types of questions asked, and their levels of confidence. Other measures such as children's level of confidence in their learning skills and a parental measure of children's confidence and leadership attributes correlated with children's trust towards informants, indicating that individual factors might play an important role in children's decision to trust others and should be further explored. Overall, these studies emphasize the need for further investigation into individual differences, such as illusory control, in children's decisions to engage in social learning when presented with various types of informants
Numerical Modeling of Fluvial Urban Floods: Implications for Flood Mitigation Strategies
No full textFluvial urban floods, also known as riverine urban floods, occur when water levels in urban streams or rivers rise rapidly due to heavy rainfall, snowmelt, or dam releases. Climate change significantly affects the severity, frequency, and predictability of floods, presenting new challenges to the relevant studies. In this thesis, numerical modeling is used to investigate the morphodynamic and inundation processes of fluvial urban floods and to explore engineering solutions to the associated problems.
The first study employed Delft-3D to develop a numerical model for examining the morphodynamic processes of the 2013 Bow River flood in Calgary, Canada. The model was calibrated using velocimetry data and validated with post-flood bathymetry data. The temporal and spatial distributions of the modeled flow and morphodynamic data were presented and analyzed. Results indicate that the timing of morphological changes during the flood varies among different morphodynamic units (MUs) but remains consistent within similar MUs. It was demonstrated that, given the same flood peak and duration, a regulated flood event with a brief rising period, as opposed to a prolonged rising period, might result in reduced bank erosion and bar growth. Additionally, bedload transport rates were found to be more sensitive to flow velocities than to bed sediment sizes in the Bow River case, due to the greater spatial and temporal variation of velocities during the flood.
Another issue arising from the 2013 Bow River flood was the flood-induced bar growth, which constricted the river channel and increased future flood risk. The second study focused on exploring the optimal bar management solution for the Bow River. Using the developed morphodynamic model, we compared the effectiveness of a traditional bar removal plan with a novel bar realignment plan. Results indicate that while appropriate bar realignment can protect aquatic habitats and provide river recreation opportunities, bar removal is more effective in reducing future flood peak levels. The findings also suggest that manipulating instream bars has minimal morphological impact on downstream reaches. This study also highlights that creating a less obstructed channel is a fundamental strategy for flood mitigation.
The third study emerged from surface image velocimetry analysis of the flow field in a large-scale physical model of flood mitigation strategies for the Bow River. We developed a new post-processing algorithm called Time Frequency Analysis (TiFA) to address challenges in Large Scale Particle Image Velocimetry (LSPIV) under unfavorable tracer conditions. TiFA involves three steps: (1) plotting the temporal frequency distribution of PIV-recognized velocities at a specific location; (2) fitting a bimodal Gaussian distribution model to the plot to identify the “most likely” velocity at that location; and (3) repeating these steps at all locations to generate a spatially distributed velocity map. We evaluated the performance of TiFA, the traditional temporal-averaging method, and the ensemble correlation method using the scaled physical model surface imagery. Results showed that TiFA produced lower errors compared to the temporal-averaging method and was at least 40% faster than the ensemble correlation method, demonstrating the great potential of TiFA in LSPIV post-processing.
While the flow characteristics of open channel confluences have been extensively studied, the inundation dynamics of urban confluence floods remain unexplored. The fourth study aims to fill this research gap by investigating a 100-year flood event at the Ottawa-Gatineau (OG) confluence in Canada, utilizing in-situ measurements, remote sensing, and a two-dimensional (2D) hydrodynamic model. A flow rating curve was first developed at the confluence outlet, showing that the total discharge and water level follow a power-law function, with minimal influence from confluence discharge ratio. The developed rating curve also showed a distinct segmentation behavior, where water level increases faster with total flow discharge in the overbank flow stage than that in the in-channel flow stage, probably due to the combined effects of the change of roughness and friction slope. Then, we employed MIKE+ to develop a two dimensional (2D) unsteady hydrodynamic model to study the confluence flood dynamics. The developed 2D model reproduced well the measured inland floodwater velocity and urban flood inundation extent, demonstrating its reliability in simulating large-scale urban confluence floods. Model results show that confluence flood inundation extent is mainly a function of total flow discharge, with minimal impact from discharge ratio or flow unsteadiness. Therefore, using steady-state models may be appropriate in future modeling of urban confluence floods