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MSpace is the University of Manitoba’s Institutional Repository. The purpose of MSpace is to acquire, preserve and provide access to the scholarly works of University faculty and students within an open access environment.

 

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Open Access
Circuit models and AMP algorithms for future-generation wireless communication systems
(2024-10-12) Akrout, Mohamed; Hossain, Ekram (Electrical and Computer Engineering); Yahampath, Pradeepa (Electrical and Computer Engineering); Heath, Robert W. (University of California San Diego); Mezghani, Amine; Bellili, Faouzi
Due to the significant increase in high data rate services and the demands of future wireless networks, researchers in the physical layer community are exploring new trends including i) integrating electromagnetic theory with communication theory, and ii) developing low-complexity digital signal processing (DSP) algorithms. This thesis aims to address gaps in the communication and DSP literatures. The first part of the thesis incorporates physical limitations of antennas, such as size and mutual coupling, into circuit models for near- and far-field communications. Traditionally, constraints like antenna size and bandwidth are not included in information-theoretic performance analysis. A key finding is that mutual coupling can widen the operational bandwidth of large-scale antenna arrays, revealing a "bandwidth gain" in massive multi-input-multi-output (MIMO) technology. The second part of the dissertation addresses recent developments in the approximate message passing (AMP) literature, where algorithms rely heavily on some assumptions (i.e., AWGN model, separable denoisers) which are not practical in many engineering applications. We extend the vector AMP approach, initially used for high-dimensional linear regression in compressive sensing, to handle arbitrary independent and identically distributed (i.i.d.) noise priors. Additionally, a bilinear generalized vector AMP algorithm is proposed, tracking the correlation matrices of the linear minimum mean square error (LMMSE) estimation. While this increases complexity, it allows the algorithm to outperform state-of-the-art solutions with discrete-valued priors. The thesis also introduces a non-separable denoiser for estimating permutation matrices, addressing the unlabeled sensing problem. Despite the computational intractability of estimating permutation matrices for even small problem sizes, the proposed unlabeled compressed sensing (UCS) approach approximates the intractable permutation denoiser using two connected assignment denoisers through a belief propagation procedure. Theoretical performance guarantees are provided through state evolution (SE) equations predicting empirical mean square error (MSE) in large systems. Simulations demonstrate the algorithm's effectiveness and superiority over existing methods. At the intersection of DSP, antenna, and communication theories, this thesis highlights the need to revisit information theoretic concepts from an electromagnetic perspective. It emphasizes the importance of circuit-based models for their ability to define and optimize the physical characteristics and constraints of communication components in an era dominated by data-driven approaches.
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Restoring Manoomin in Brokenhead Ojibway Nation through a community-led approach: implications on food security and the local economy
(2024-09-18) Nwankwo, Uche; Brewin, Derek (Agribusiness and Agricultural Economics); Bobiwash, Kyle (Entomology); Thompson, Shirley
Manoomin (Zizania palustris), also known as wild rice, is a culturally, spiritually, nutritionally, and ecologically important plant to the Ojibway people. Production and management of Manoomin are deeply rooted in Indigenous food system knowledge (IFSK), which was negatively affected by colonial legacies. This research asked whether Manoomin production can play a significant role in the Ojibway economy amid high food insecurity, structural barriers to traditional food access, and challenges to sustainable livelihoods. My mixed methodology research employed the need-based approach (NBA) in investigating a sustainable pathway to restoring Manoomin to Brokenhead Ojibway Nations (BON). Community members enrolled in the Kitigay pilot program, a project-based post-secondary education program, took the lead in restoring Manoomin in BON and transforming the abandoned weedy Bison Ranch farm for gardening and orchard planting. An initial 60 pounds of Manoomin was procured and planted in BON Rivers in October 2024, with community members' active participation. Later, a community café was organized in collaboration with community members. The community café’s impact resulted in the BON Chief and Council purchasing and planting an additional 2,000 pounds of Manoomin in 2023, applying IFSK. A community café, survey, and participatory action research undertaken in this study indicate that Manoomin is regarded as an essential component of the Ojibway people’s food chain, economy, and environment. Eighty-one percent of the 21 participants who completed the semi-structured survey indicated the likelihood of participating in future community-led Manoomin restoration projects. In ranked order (1 = not at all important to 5 = very important), the three most compelling reasons among ten variables for participating in the community café are transferring IFSK to the youth (90%), reviving IFSK (88%), and income and employment opportunities (86%). The Spearman’s correlation results suggest a strong positive correlation between reviving IFSK and transferring IFK to the youth (r =.67, n = 21, p < .001). A strong positive correlation exists between reviving IFSK and decolonizing IFSK (r =.57, n = 21, p < .007). The Manoomin restoration in BON presents a compelling argument for community-led participatory approaches to addressing food insecurity problems in Indigenous communities.
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Open Access
Knowledge Synthesis Research in the Rady Faculty of Health Sciences
(2024-08-29) Lê, Mê-Linh; Linton, Janice; Monnin, Caroline
Knowledge synthesis, which includes systematic reviews, scoping reviews, and rapid reviews, is an important form of research for the Rady of Faculty of Health Sciences. But how is this research completed, what services are available to support students and researchers doing this work, and what does published KS from the RFHS look like over the last six years? Librarians from the Neil John Maclean Health Sciences Library have collaborated with RFHS faculty, students, and researchers on hundreds of reviews, consulted on innumerable projects, answered thousands of knowledge synthesis questions, and provided hours of in-class and online instruction. Since 2018 we have also offered a multi-part workshop series that allows attendees to add it to their Experience Record. We also recently completed a research study that identified all published KS research produced by the RFHS community since 2017. This allowed us to conclusively identify trends in the overall increase in KS, the incredible growth of specific review types, and possible relationships between librarian collaboration on a KS and the journal impact factor of the published research. Pulling from these two information sources, this presentation will provide an overview of KS research output at RFHS and outline supports available to KS researchers. This session will be valuable for anyone involved in KS research within the RFHS – whether as summer research students or longtime KS investigators.
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Open Access
Trends in Evidence Synthesis and Growth in Librarian Involvement
(Library Evidence Synthesis Services Symposium (LESSS), 2024-06-27) Monnin, Caroline; Lê, Mê-Linh
This study examines the evolving role of librarians within evidence synthesis (ES) research at a mid-sized university after the introduction of a tiered service model. We identified all ES published by our institution and used content analysis to categorize the type of evidence synthesis (e.g., systematic reviews, scoping reviews), the disciplines represented (e.g., nursing, psychology), and the specific ways librarian contributions were credited or acknowledged (e.g., co-authorship, mentioned by name in the search methods). Findings highlight a significant increase in librarian co-authorship since the introduction of our tiered model in 2017, reflecting a growing recognition of librarian expertise in evidence synthesis methodologies and the possible impact of our tiered model. Additionally, our research reveals overall trends in output and disciplines publishing ES research. This presentation is valuable for librarians and administrators planning their own ES research service and those interested in learning how a tiered model can result in increased acknowledgement and co-authorship for librarians involved in evidence synthesis research. Slides were presented as part of the Library Evidence Synthesis Services Symposium (LESSS) which occurred June 24-27, 2024.
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Designing and testing a prototype stable-wing-support system to deploy, retrieve, and operate a horizontal river hydrokinetic turbine within the water column to achieve cost-effective power generation in cold climates
(2024-10-05) Aqdiam, Ibrahim; Wu, Nan (Mechanical Engineering); Mantilla, Ricardo (Civil Engineering); Bibeau, Eric
River hydrokinetic turbines harness renewable energy in river currents to contribute to microgrids. Despite many hydrokinetic turbine designs, systems still require reducing costs and operate effectively in cold climates. A stable-wing-support system is developed and tested to deploy, retrieve, and operate within the water column of a horizontal axis river turbine. The prototype design addresses identified stability problems using a fixed-wing design previously tested in a laboratory water tunnel and an energetic river. The stable-wing-support system prototype uses a NACA 0012 airfoil with 6°, 10°, and 15° dihedral angles designed using open-source Xflr5 software to optimize the lift, drag, and moment coefficients for angles of attack from -5° to +15°. The prototype also includes a winged tail to improve the turbine assembly's stability further. The stable-wing-support prototype designed using SolidWorks is 3-D printed. Tests are conducted to quantify the stability of the stable-wing-support prototype using a water tunnel at flow velocities varying from 0.5 to 1 m/s, resulting in Reynold’s numbers from 3.37x105 to 6.74x105. Stability data is recorded and analyzed using open-source Tracker software and then exported to MATLAB software for analysis. Results indicate that the stability of the stable-wing-support system with dihedral angles 6°, 10°, and 15° and a winged tail significantly improves the stability by 80%, 50%, and 40%, respectively, compared to a previous design for flow velocities up to 1 m/s, addressing the objectives of this research and contribute a design to maximizing power production in cold climates.
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Open Access
Detecting energy dissipation in modulated vs. non-modulated motion waveforms emanating from vibrating systems recorded in videos
(2024-10-04) Uswatta Liyanage, Tharaka; Hossain, Ekram (Electrical and Computer Engineering); Bartz, Jamie (Civil Engineering); Peters, James
The research investigates the dynamics of motion energy dissipation in modulated versus non-modulated motion waveforms derived from vibrating systems as recorded in video formats, utilizing Hilbert transforms for signal analysis. By defining the critical motion attributes through the Hilbert spectral analysis, the study quantifies the energy dissipation in both modulated and non-modulated states, capturing the intricate oscillatory behavior of these systems. The essence of modulation in this context is demonstrated through the localized concentration of energy, observable in systems ranging from mechanical to human motion. In contrast, non-modulated signals exhibit dispersed energy profiles, leading to different implications for energy efficiency and system performance. Through meticulous frame-by-frame analysis, the research delineates how specific energy patterns can lead to smoother motion waveforms as well as resulting a decrease in system vibrations.
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Open Access
Dynamic phasor modelling and simulation of power networks with converter-tied renewable resources
(2024-10-03) Peiris, Paranagamage; Gole, Aniruddha (Electrical and Computer Engineering); Muthumuni, Dharshana (Electrical and Computer Engineering); Chen, Christine (University of British Columbia); Filizadeh, Shaahin
Due to the massive integration of renewable energy generation in modern power systems, the dynamic characteristics of the power grid are rapidly changing. Spurred by device limitations and the wide range of controls present in converter-based generation, the resulting reduction in system inertia and system strength warrant improved modelling methods that provide analytical insight into the operation of modern power systems. Conventional approaches for analysing transient and small-signal stability are being challenged due to the new, non-linear controls present in converter-based generation. Due to their inability to represent the network dynamics, conventional phasor-based methods are no longer suited for detailed studies in converter-based systems. Electromagnetic transient (EMT) based methods successfully capture the dynamic characteristics of such systems but are restricted in terms of their capability to provide analytical insight using formal means such as eigenvalues. This thesis proposes a modelling approach based on average-value, positive-sequence dynamic phasors, that can integrate transient simulation and small-signal studies into a singular modelling platform. A component based modular approach to develop the model of a large power system is presented and is benchmarked against EMT and conventional phasors demonstrating its accuracy on par with EMT simulations, while also providing analytical insight through eigenvalue analysis. The proposed modelling method is parallelized using graphics processing units (GPUs) providing significant performance gains over EMT simulations. A limitation of the proposed modeling method, which arises with networks with all inductor nodes, is addressed using a novel method that allows both transient responses and eigenvalue analyses with a significant reduction in model order. Finally, an example case is studied determining the operational parameters for grid-following and grid-forming converters for stable operation. Based on both eigenvalue analysis and transient responses, this is analysed for a single machine infinite bus (SMIB) system for a case with reducing short circuit strength and a case of network strengthening through series compensation.
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Open Access
Energy-aware and RIS-assisted communications in UAV-based wireless networks
(2024-09-26) Sekander, Silvia; McLeod, Robert D. (Electrical and Computer Engineering); Wang, Yang (Computer Science); Zhao, Lian (Toronto Metropolitan University); Hossain, Ekram
Unmanned aerial vehicles (UAVs) advance 5G and 6G networks with flexible deployment and enhanced coverage. However, their limited onboard energy poses challenges, requiring optimization through advanced energy harvesting, flight planning, and adaptive protocols. On the other hand, Reconfigurable Intelligent Surfaces (RISs) are emerging as a transformative technology for future wireless systems, particularly in the context of 6G for dynamically improving signal strength and coverage. Integrating RISs with UAVs addresses propagation issues, enhancing communication with RISs on buildings or UAVs. However, several critical research areas remain unexplored. These include understanding the complex radio wave propagation characteristics in aerial environments, optimizing the deployment of 3D RIS arrays to maximize their benefits in dynamic scenarios, and ensuring seamless integration of UAVs and RISs into existing and future wireless standards. Overcoming these challenges will be pivotal in harnessing the full potential of UAVs and RISs to meet the demanding requirements of 6G networks, thereby ushering in a new era of pervasive and high-performance wireless connectivity. This thesis addresses UAV-assisted communication challenges, focusing on energy harvesting and deployment optimization. It models solar, wind, and hybrid energy scenarios, deriving expressions for harvested power to evaluate outage probabilities using moment generating functions (MGF) and Gil-Pelaez inversion. It also explores distributed STAR-RIS networks versus multi-antenna UAV systems, optimizing multi-user scheduling, STAR-RIS shifts, and UAV beamforming using semi-definite programming, integer relaxation, and convex approximation, showing significant performance gains and enhancing UAV efficiency.
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Open Access
Quantization of random orthonormal matrices with application to adaptive transform coding
(2024-09-23) Boragolla, B. N. Weerasinghe Mudiyanselage Rashmi Amadini; Sherif, Sherif (Electrical and Computer Engineering); Ashraf, Ahmed (Electrical and Computer Engineering); Bajić, Ivan (Simon Fraser University); Yahampath, Pradeepa
This thesis explores the quantization of orthonormal random matrices, an important component in the adaptive transform coding of images and video. While vector quantization in Euclidean space has been extensively studied, applying these methods to orthonormal matrices is challenging due to the inherent orthogonality constraints. Directly solving the constrained optimization problem in Euclidean space is difficult. Therefore, this research investigates several novel constructive approaches to the quantization of orthonormal random matrices, specifically for application in video and image compression. These matrices serve as approximations to the Karhunen-Loève Transforms (KLTs) of pixel blocks in images. The main objective of this thesis is to design an optimal codebook of transform matrices that can be utilized in adaptive transform coding, thereby enhancing compression efficiency. This thesis first investigates solving the constrained optimization problem in Euclidean space as an unconstrained optimization problem on the orthonormal matrix manifold. The primary goal is to minimize the mean square error (MSE) of transform coding, and this thesis derives an objective function for minimization based on high-rate analysis. Since the minimization problem lacks a closed-form solution, this thesis proposes a coordinate descent algorithm, which is guaranteed to converge to a local minimum. The proposed algorithm can be used to design both separable and non-separable transforms from sample image data. Experimental results demonstrate that adaptive transform coding using codebooks designed by the proposed algorithm outperforms both non-adaptive coding based on the widely used two-dimensional discrete cosine transform (2D-DCT) and adaptive coding using transform codebooks designed by various recently reported methods. This thesis further investigates a model-based approach to transform matrix codebook learning by modeling natural image blocks as finite lattice non-causal homogeneous Gauss Markov random fields (GMRFs) with Neumann boundary conditions. The proposed method involves the estimation of GMRF parameters. While the standard approach for GMRF parameter estimation is maximum likelihood, this thesis introduces a novel method based on high-rate analysis of transform coding, which focuses on minimizing the MSE of transform coding. In the proposed codebook design approach, the quantization of an orthonormal matrix is carried out in the parameter space of GMRF, transforming the complex task of quantizing a large matrix with orthonormality constraints into a much simpler task of vector quantization in a reduced-dimensional space. A very important advantage of the proposed method is that it can be easily used to design transforms for variable block-size adaptive transform coding. Experimental results are presented for adaptive transform coding of still images which compares the proposed approach against various other alternatives recently reported in the literature. Finally, this thesis addresses the problem of predictive quantization of a random orthonormal matrix process. While predictive quantization is commonly used to quantize correlated processes in Euclidean space, these methods are not directly applicable to processes on a manifold. The approach proposed in this thesis views the prediction problem as one of tracking KLT matrices on the orthonormal matrix manifold. A definition for matrix prediction error on the manifold is proposed. Numerical results demonstrate the effectiveness of utilizing predictive quantization of transform matrices to improve transform coding gain.
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Open Access
Environmental assessment and impact of air, water and noise levels near a cement factory in Ewekoro, Ogun State, Nigeria
(2024-09-15) Awos, Alaba; Zvomuya, Francis (Soil Science); Zhang, Qiang (Biosystems Engineering); Oludare, Adedeji (Federal University of Agriculture, Abeokuta Nigeria); Thompson, Shirley
The air, water and noise were assessed for respirable particulate matter (PM2.5 and PM10) and heavy metals (lead, chromium, nickel, cadmium, zinc and copper) and noise levels around a cement factory in Ewekoro. Air was sampled using a cassette sampler and was taken at Ewekoro and neighbouring communities (Papalantoro, Lapeleko and Itori) in Nigeria’s Ogun State. An atomic absorption spectrometer (AAS) measured heavy metals in the water, and a sound level meter was used to monitor the noise levels. Comparing levels with the World Health Organization (WHO), National Environmental Standard and Regulation Enforcement Agency guideline (NESREA, Nigeria) and Canadian Ambient Air Quality Standards (CAAQS) show some standards were exceeded. The mean concentrations of Cadmium (Cd), Chromium (Cr) and Nickel (Ni) in the air of the cement factory area and the impacted neighbourhoods were higher than the WHO/EU permissible limits. Chromium's hazard quotient (HQ) was above the WHO/EU safe level in adults and children through ingestion, inhalation and dermal contact in all areas monitored. Also, the HQ for Ni and Cd were higher than the safe levels in the cement factory area and Papalantoro but not in other areas, while Zinc (Zn) was determined to be at safe levels. All heavy metals monitored in the river water, except Zn, exceeded the WHO permissible limit. The heavy metal sources cannot be pinpointed to the cement factor as other points and non-point contamination sources exist. The hazard index (HI) was greater than one in all the rivers monitored in children and adults, signifying an unacceptable health risk for non-carcinogenic effects. The HI for children in all the rivers sampled was higher than that for adults, indicating that children will experience more non-carcinogenic health risks than adults. The sum of Incremental lifetime cancer risk (∑ILCR) of both adults and children was higher than the acceptable level. The highest daily noise level result at the cement factory was below the NESREA regulatory standard, while the result at the residential area was slightly higher than the standard.