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Local search based approximation algorithm design and analysis
No full textWe study four {\em combinatorial optimization} problems from the perspective of approximation algorithms. All the problems are {\em NP-hard} and model many real-life applications. The main design technique is {\em local search} and the main performance analysis technique is {\em amortization}.
The first problem \MPCV{k} aims to cover the maximum number of {\em vertices} by a collection of vertex-disjoint -paths. We present the first -approximation algorithm for every and an improved -approximation algorithm for . Those algorithms consists of one or more local search operations and the approximation ratio is proved by amortized analysis. When , we improve the ratio to by constructing a feasible solution from a maximum matching. The second problem \MPCE{k} aims to cover the maximum number of {\em edges} by a collection of vertex-disjoint length -paths. We present the first algorithm for every achieving -approximation, which employs a valuable set to update the current solution.
For , we present another improved -approximation by modifying a maximum triangle-free path-cycle cover into a feasible solution.
The third problem PP aims to find a minimum collection of vertex-disjoint -paths such that each vertex is exactly on one of those paths. We present a -, and -approximation algorithm for , and , respectively. Our algorithms improve the previous best approximation ratios when .
The last problem -LRS aims to find a longest run subsequence in the input sequence where each symbol can appear at most times. We show an improved -approximation algorithm for and a -approximation algorithm for . We distinguish the bad symbols in the sequence and then, design two operations to minimize the number of bad symbols that only appear once in the current produced solution
Development and Optimization of Methods for Microplastic Analysis in Drinking Water: A Case Study of Glenmore Drinking Water Treatment Plant, Calgary
No full textIn recent years, the presence of microplastics (MPs) in drinking water has garnered increasing attention due to their potential impact on human health. MPs are plastic particles ranging from 1 µm to 5 mm and can have varying size, morphology, and chemical composition. Although their full impact on human health remains unclear, characterizing the MPs and understanding their fate throughout the drinking water production process is crucial to managing potential risks. This thesis investigates the presence of MPs larger than 10 µm in raw and treated water from the Glenmore drinking water treatment plant (G-DWTP), one of the two facilities supplying drinking water to the City of Calgary. To facilitate the study, a novel sample collection device was developed to collect large (~1000 L) sample volumes for analysis. Experiments were conducted to improve particle recoveries by evaluating the application of high-pressure flushing (HPF) and ultrasonic treatment. Additionally, the optimal magnification for Raman microspectroscopic analysis of different-sized particles was assessed. Monthly samples from April–September 2024 were collected from both raw and treated drinking water. After pretreatment, samples were stained with Nile Red and suspected MPs were identified by fluorescence microscopy and analyzed using Raman microscopy for identification of their polymer composition.
For sample pretreatment, the optimal procedure involved assembling the filter support and mesh together, followed by a one-minute ultrasonic treatment and HPF. This pretreatment method yielded differing recoveries across various size ranges: 76.7 ± 20.9% for 250-300 µm, 75.3 ± 7.8% for 106-125 µm, 64.6 ± 13.3% for 63-70 µm, and 26.3 ± 7.1% for 10-20 µm. The optimal magnification was 10x for particles larger than 90 µm and 50x for those smaller than 90 µm. The measured abundance of MPs in the raw water was 1.9 ± 2.8 MPs/m3, with a slight increase to 3.1 ± 3.1 MPs/m3 in the treated water. Among the detected MPs, particles in the size range of 1-80 µm accounted for 73%. Three morphological types of MPs were identified: fragments (89%), beads (8%), and fibers (3%). The predominant polymer types were polypropylene, polystyrene, polyethylene, and polyvinyl chloride. In terms of color, white and transparent MPs were the most common, comprising 54%, and 32% of the total, respectively. Overall, MP abundance at the G-DWTP was relatively low compared to other studies.
This thesis represents the first assessment of MPs in the G-DWTP. While it provides baseline information, establishing a monitoring plan is important to adequately assess MP risks. Finally, acceptable particle recoveries achieved through the design of the sampling equipment and methods development offer valuable reference points for MPs monitoring activities at other DWTPs in Calgary
Intersection Rules Impact on Haul Truck Productivity in Mining Operations: An Analysis Using HaulSim
No full textMaterial loading and hauling are foundational processes in the mining industry, accounting for over 50-60% of a mine’s total operational costs. The truck-shovel system, central to haulage operations, has been extensively researched to optimize fleet management and improve cost efficiency in open-pit mines. Fleet management systems (FMS) are widely implemented to maximize productivity and reduce costs by refining truck allocation and dispatching. However, operational challenges persist, particularly those arising from truck operator behaviors, such as excessive brake use, inefficient road design, and unnecessary stops at intersections. These factors, often difficult to quantify, add to travel times and production efficiency, highlighting a need for targeted intersection management solutions.
This study addresses these challenges by evaluating intersection-passing rules to assess traditional methods, specifically the Loaded Truck First (LTF), Give Way, and 4-way Stop models, which have been used extensively in mining operations. These methods are evaluated for their effectiveness in maintaining truck flow, reducing idle time, and minimizing delays at intersections. Utilizing Haulsim simulation software, the research replicates real-world mining conditions in open-pit operations to evaluate the algorithm’s performance against existing methods, focusing on productivity metrics such as cycle time and overall production efficiency.
The results revealed that the LTF algorithm consistently delivered superior productivity, especially when applied to smaller truck units, by prioritizing ore-loaded and empty trucks and selectively delaying waste trucks. The Give Way model also showed strong performance, reducing idle time and fuel consumption while enabling smooth traffic flow for larger truck units. Conversely, the 4-Way Stop strategy led to increased operational delays, fuel use, and carbon emissions due to frequent stopping, making it the least efficient of the three.
Through this comparative analysis, the study investigates how different intersection control protocols influence the efficiency of haul trucks and overall productivity. Results are expected to reveal the benefits of optimized intersection management, demonstrating reductions in operational bottlenecks, improved flow of trucks at intersections, and a decrease in idle times at loading and unloading points. By providing a robust framework for assessing and optimizing haulage cycles, this research offers actionable insights for both operational strategies and long-term productivity planning in open-pit mining. The findings aim to advance the understanding of intersection dynamics in mining haulage, contributing to mine planning and fleet management optimization
“I like going into town and eating food”: analyzing the discursive construction of rural youth food environments in Canada
No full textRurality is an under-researched dimension of youths’ food environments. This qualitative study engaged youth (aged 13–18) in two rural settings in western Canada to examine the discourses shaping their experiences of their food environments. Data were generated through individual and group interviews during cooking sessions. Using discourse analysis, we identified three discourses: moralizing eating practices; moving beyond food and nutrition binaries; and valuing food and nutrition knowledge and skills. These discourses reflect both hegemonic and counter-hegemonic discourses of food and nutrition. Study findings have implications for developing and implementing health-promoting nutrition interventions for youth in rural communities
Field and Dispersion Engineering in Cylindrical Metallic Waveguides using Cascaded Metasurface Liners
No full textThis work presents a comprehensive method for analyzing the dispersion characteristics and electromagnetic field distributions in cylindrical metallic waveguides lined with cascaded MTS and dielectric layers using the matrix approach. Analytical equations are derived to predict the dispersion relation and electromagnetic fields within a metallic waveguide for a given MTS liner configuration. By designing the metasurface layers, the waveguide’s dispersion and field distribution properties can be tailored and controlled. To this end, a root-finding algorithm based on the Particle Swarm Optimization (PSO) method is developed to optimize the surface parameters of the layers for different electromagnetic functionalities, such as controlling the polarization, field properties, and propagation of different modes. Design examples, validated through simulations in ANSYS HFSS, demonstrate the accuracy and practicality of the method. In conclusion, this study provides valuable insights and tools for engineering the dispersion and field distribution properties of cylindrical waveguides. These findings have potential applications in systems requiring control of electromagnetic wave behavior
Leadership in Kenyan Public Universities: Structural Forces and Transformative Futures
No full textThe paper employs a qualitative desktop research approach and adopts Baldridge’s Political model framework, drawing on the regulatory framework established by the University’s Act No. 42 of 2012 to examine how structural forces, such as political interference, shape university leadership and governance.
The analysis suggests that leadership challenges are mainly driven by deep-rooted systemic factors such as ongoing political interference in appointments of key leaders, overlapping regulatory roles, university chronic underfunding by government, and uneven digital infrastructure. These dynamics undermine institutional independence, weaken leadership and governance, and make conflict a standard aspect of university operations.
The paper recommends transparent and merit-based appointment processes, streamlined regulatory coordination among key oversight institutions, sustainable public funding of universities, and enhanced digital governance capacities. Additionally, it advocates for adoption of ethical, and adaptive leadership practices to advance gender equity, digital justice, and socially responsive university leadership and governance
Yuting (Cindy) Sun - Abstract 31 - Innovate Conference 2025
No full textThe COVID-19 pandemic escalated concerns about high nurse turnover and shortages in Canadian intensive care units (ICUs). Several studies highlight frequent changes in nursing demands, moral distress, and interprofessional conflicts as contributing factors to nurses leaving their jobs. However, there remains a gap in research exploring nurse turnover intentions in critical care settings.
Objective: This study aims to understand factors influencing ICU nurses across Alberta to stay in or leave their positions following the pandemic
Build up the Kingdom: Water and Power in the American West, 1100-2025
No full textThis paper employs a narrative-based historical approach to assess the relationship between water and power in three connected cases in the American West. This was done through the lens of Karl Wittfogel9s Oriental Despotism, while equally relying on Stephen Lukes9 view of power as expressed in Power: A Radical View to further break down the kinds of power used in each case. The first chapter is an analysis of the early Mormon settlement and Mormon hydraulic management, which is an understudied topic in discussions of water in the American West. The second chapter concludes the narrative with the Mormon settlement in Alberta and a discussion of the modern Albertan irrigation system and both its future potential and challenges. Lastly, a brief epilogue paints the broad sketches of a possible future using the trends highlighted in the three discussion chapters. There is also an appendix which discusses in substantial detail the current evidence for pre-Columbian hydraulic regimes
The Aesthetic Experiments of Preservice Teachers: Towards the Possibility of a Livable Life in the Teaching Profession
No full textBuilding Inclusion Capacity in Early Childcare Settings: Replication of the Pyramid Model in Alberta
No full textThis thesis examines a community-based replication of the Pyramid Model (PM) for promoting young children’s social–emotional competence in Alberta’s early learning and childcare (ELCC) sector through the Access, Support, and Participation (ASaP) initiative. Addressing the limited Canadian evidence base, the study evaluates implementation fidelity at both ELCC educator and program levels and explores how practice-based coaching (PBC) and leadership supports relate to change over time. A quantitative, longitudinal design was used. Fidelity data were collected between March 2022 and March 2024 using the Teaching Pyramid Observation Tool (TPOT; educator practice), Program-Wide Implementation Benchmarks of Quality (PWI-BoQ; program supports), and structured coaching logs. The analytic sample included 11 centres with complete multi-wave fidelity data and coaching records. Analyses included descriptive statistics, repeated-measures ANOVA, and correlations linking coaching exposure, program fidelity, and classroom practice. ELCC programs participated in ASaP for an average of 21 months. Educator fidelity rose from 40% at baseline to 74% at the fourth observation, with significant linear gains across most domains. PM program implementation supports increased from 28% to 72% across three waves. Time in ASaP correlated positively with stronger educator practices at mid- and late implementation (r = .741 at Time 2; r = .801 at Time 4). Greater leadership consultation was linked to higher TPOT scores at Time 4 (r = .544). The relationship between program implementation supports and educator practices strengthened over time, reaching significance at Time 3 (r = .773) and Time 4 (r = .900). With four educators achieving high-fidelity PM practices and five ELCC programs reaching program-wide implementation fidelity (80% across domains), this study offers preliminary evidence of the strength of the ASaP program in their delivery of the PM framework in a Canadian context. Findings suggest that ASaP’s blended supports—including professional learning, sustained coaching, and leadership consultation—are linked to meaningful, time-ordered improvements in PM fidelity within Canadian ELCC settings. Practically, systems may benefit from planning for 18–24 months of support and maintaining stability in coaching, leadership, and program monitoring data routines. Limitations include the small sample and absence of a comparison group. Future research should employ comparative designs, link fidelity to child outcomes, assess sustainment, and examine cost-effectiveness for provincial scaling