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Reduced-complexity modelling of decadal-scale shoreline change
No full textRobust and reliable models are needed to understand how coastlines will evolve over the coming decades, driven by both natural variability and climate change. While many models of shoreline change have been developed for sandy coasts and are increasingly being used to generate forecasts to the end of the century, few studies have evaluated how these models perform over such multi-decadal timescales. This thesis evaluated the performance of six recently developed models against a high-quality 40-year dataset of monthly shoreline change at Narrabeen-Collaroy Beach in southeast Australia, one of very few such datasets globally. The six models selected were ‘reduced-complexity’ hybrid frameworks that each couple popular sub-models of cross-shore and longshore processes. This class of models has been identified by multiple recent reviews to be most promising for multi-decadal simulations. The complex cross-shore and longshore dynamics at Narrabeen-Collaroy Beach, varying both spatially alongshore and temporally at interannual timescales, provided a rigorous test for the coupled model frameworks.Modifications to the set-up of five of the six models were required to achieve a stable output at this site. Some models were found to be excessively sensitive to decadal-scale shifts in the wave climate, while others (using the popular ‘one-line’ approach as a sub-model to simulate longshore sediment transport) were very sensitive to small biases in nearshore wave direction. Following modifications, the six models showed similar performance across the embayment on average but with large variability between transects. Their performance was promising considering their simplicity and low computational cost, but likely not yet sufficient for routine applications to inform coastal management. In particular, the models appeared to aggregate key processes at this timescale into parameter values rather than capturing them directly, suggesting time-varying parameters and/or changes to model structure may be necessary for decadal-scale simulations. The results also highlighted the importance of site-specific calibration, validating performance against unseen data, and testing models across morphodynamically different sites.Subsequently, given the popularity of one-line models and the high sensitivity to wave direction bias observed in these results, a standalone one-line model was used to test three methods to correct for this issue. Two methods corrected the input wave conditions while the third corrected the output modelled shoreline positions. The methods provided different degrees of trade-off between computational expense and the resulting effectiveness of the correction. No solution was ‘optimal’, but different solutions may be best suited for different cases.Finally, recent advances in extracting shoreline positions from satellite imagery with sub-pixel accuracy have resulted in a transformative step forward for the field, providing an unprecedented global 35-year dataset of shoreline change. A simple comparison between two models calibrated with shorelines derived from field survey data, satellite imagery, and aerial photogrammetry illustrated that the error of satellite-derived shorelines appears to be within the error already inherent in reduced-complexity models and does not substantially affect their performance for ‘best-case scenario’ sites such as Narrabeen-Collaroy Beach. It is argued that utilising this data to achieve site-specific calibrations for individual beaches, and to test the performance of shoreline change models over a much broader range of morphodynamically diverse sites than previously possible, will be key to further advancing our ability to model shoreline change over multi-decadal timescales.</p
Adversarial Learning in Unmanned Aerial Vehicles-aided Intelligent Transportation Systems
No full textWith their inherent attributes such as mobility, flexibility, and adaptive altitude, Unmanned Aerial Vehicles (UAVs) can potentially enable Intelligent Transportation Systems (ITS) to be more efficient for data collection, data analysis, and communication networks. UAVs are equipped with machine learning and Deep Neural Network (DNN) models to enhance their capabilities for applications across various safety-critical domains, particularly traffic management in ITS. However, it has been demonstrated that these models are highly susceptible to adversarial attacks, which are defined as imperceptible changes to pixels of the actual input to statistically impact the decision of the machine learning and DNN models.In this thesis, we explore the potential contributions of UAVs to ITS and examine how UAVs can enhance various aspects of ITS, such as traffic monitoring, congestion management, and emergency response. Furthermore, we analyze the pivotal role that machine learning techniques play in enabling this synergy. A thorough survey aiming to explore a quantitative understanding of widely used DNN models via a series of experiments and comparisons is presented. To investigate the influence of adversarial attacks on DNN-based aerial vehicle detection and traffic extraction from UAV videos, we propose a white-box adversarial threat model to periodically manipulate critical frames and pixels with the most impact on aerial vehicle detection and tracking. To protect UAV-based vehicle detection and tracking systems, we present adversarial detection and cleaning. To detect adversarial frames, multi-level temporal consistency analysis is utilised to capture both short-term and long-term dependencies in video sequences by detecting inconsistencies in frame predictions.</p
Understanding cybersecurity behaviour and attitudes of young adults in Saudi Arabia
No full textThe abstract for this item has not been populated.</p
Three-dimensional bioprinted in vitro glioma tumor constructs for synchrotron microbeam radiotherapy dosimetry and biological study using gelatin methacryloyl hydrogel
No full textSynchrotron microbeam radiotherapy (MRT) is an innovative cancer treatment that uses micron-sized of ultra-high dose rate spatially fractionated X-rays to effectively control cancer growth while reducing the damage to surrounding healthy tissue. However, the current pre-clinical experiments are commonly limited with the use of conventional two-dimensional cell cultures which cannot accurately model in vivo tissue environment. This study aims to propose a three-dimensional (3D) bioprinting gelatin methacryloyl (GelMA) hydrogel protocol and to characterize 3D bioprinted glioma relative to cell monolayer and spheroid models for experimental MRT using 9L rat gliosarcoma and U87 human glioma. Synchrotron broad-beam (SBB) and MRT beams were delivered to all cell models using 5, 10, and 20 Gy. 3D bioprinting enables the creation of 3D cell models that mimic in vivo conditions using bioinks, biomaterials, and cells. Synchrotron dosimetry, Monte Carlo simulation, in vitro cell viability, and fluorescence microscopy were performed to understand the relationship of the radiation dosimetry with the radiobiological response of different cancer models. Encapsulated gliomas were placed inside 3D printed human and rat phantoms to mimic scattering conditions. Results showed that MRT kills more gliomas relative to SBB for all cell models. The 3D bioprinted culture detected the spatial clustering of dead cells due to MRT high peak doses as seen in fluorescence imaging. The result of this study progresses MRT research by integrating 3D bioprinting techniques in radiobiological experiments. The study’s bioprinting protocol and results will help in reducing the use of animal experiments and possibly in clinical translation of MRT.</p
Development of a Point of Care 3D Bioprinting System for Wound Healing Applications
No full textIn the quest to improve both aesthetic and functional outcomes for patients, the clinical care of full-thickness cutaneous wounds has undergone significant development over the past decade. A shift from replacement to regeneration has prompted the development of skin substitute products, however, inaccurate replication of host tissue properties continues to stand in the way of realising the ultimate goal of scar-free healing. Advances in three-dimensional (3D) bioprinting and biomaterials used for tissue engineering have converged in recent years to present opportunities to progress this field. However, many of the proposed bioprinting strategies for wound healing involve lengthy in-vitro cell culture and construct maturation periods, employ complex deposition technologies, and lack credible point of care (POC) delivery methods. To survive the journey to bedside, printing protocols must be curated, and biomaterials/cells selected which minimise treatment time and facilitate rapid, single-stage wound closure.In this thesis, we present a novel approach to this clinical challenge by developing a fit-for-purpose in-situ extrusion bioprinting system for full-thickness wound treatment at POC. Our approach was to additively fabricate constructs laden with ReCell™; a clinically regulated autologous cell source which can be rapidly harvested at POC. We hypothesised that the heterogeneous mixture of uncultured dermal and epidermal skin cells would self-assemble in response to endogenous cues in-vivo, thereby facilitating full-thickness wound healing.In Chapter 3, bioprinting hardware components, including a custom colinear extrusion nozzle and handheld delivery device dubbed the ‘Dermifix’ were designed and developed. The colinear extrusion nozzle was characterised to confirm side-by-side ink deposition, competitive print resolution capabilities and flexibility to alter construct composition by modulating individual ink contributions. The ergonomic design of the Dermifix was showcased through proof-of-concept manual extrusion and precise multi-layer deposition in-vitro. Additionally, hardware components for the spray delivery of an exogenous crosslinking solution were characterised, highlighting the ability of the ReCell™ kit nozzle to deliver crosslinkers in a controlled manner in-situ using optimised operating pressure settings.The bioprinting hardware developed in Chapter 3 was then employed in Chapter 4 to fabricate multi-material constructs using a novel colinear extrusion method. Ink formulations were optimised to enable the controlled fabrication of multi-layer cross-hatched constructs laden with macropores and rich in cell attachment sites, serving to facilitate the retention of cells and their subsequent migration during self-assembly. A ReCell™ mimic cell suspension containing human dermal fibroblasts (HDFs) and human epidermal keratinocytes (HKs) was developed and subsequently incorporated into the printing process to show that bioprinted constructs supported the survival, attachment and proliferation of both cell types in-vitro.Finally, in Chapter 5, the proposed handheld bioprinting system was evaluated in-vivo for the treatment of full-thickness porcine wounds at POC. During this investigation, the effect of utilising an autologous ReCell™ suspension in place of the ReCell™ mimic developed in Chapter 4 was highlighted. Specifically, it was shown that residual enzyme molecules in the ReCell™ suspension acted to prematurely degrade the carrier bioink formulation, in turn, diminishing its printability. This challenge was addressed in a follow-up in-vivo experiment by supplementing the bioink formulation with human platelet lysate (HPL). In-situ bioprinted constructs were shown to accelerate wound re-epithelialisation compared to a popular POC treatment method (Integra®). The incorporation of ReCell™ to the bioink formulation did not have a significant impact on the wound healing outcomes assessed, nor did we observe the hypothesised self-assembly of ReCell™ in-vivo. Nevertheless, feasibility of the system at POC was demonstrated for the timely treatment of wounds up to 4 cm2 in size.Taken together, the proposed 3D bioprinting system holds significant promise as a tool for POC full-thickness wound treatment. The data presented in this thesis establishes a foundation for the further refinement of hardware and ink compositions, aiming to realise improved patient outcomes in the future.</p
Longitudinal Associations Between Movement Behaviours and Development Among Infants Using Compositional Data Analysis
No full textBackground: The study examined the longitudinal associations of sleep time, restrained time, back time and tummy time with development in a sample of infants using compositional data analysis. Methods: Participants were a subsample of 93 parent–infant dyads from the Early Movers project in Edmonton, Canada. Parents completed a 3-day time-use diary at 2, 4 and 6 months of age. Time spent in four mutually exclusive movement behaviours were calculated representing sleep (i.e., sleep time), sedentary behaviour (i.e., restrained time and back time) and physical activity (i.e., tummy time). Communication, fine motor, gross motor, personal-social, problem solving and total development were measured at 2, 4 and 6 months of age with the Ages and Stages Questionnaire (ASQ-3). Gross motor development was also measured by a physiotherapist using the Alberta Infant Motor Scale (AIMS) at 6 months. The age six major gross motor milestones (i.e., independent sitting, crawling, assisted standing, assisted walking, independent standing, independent walking) were achieved according to World Health Organization criteria, in the first 18 months of life, were calculated. Results: The composition of movement behaviours across time points was significantly associated with: ASQ-3 gross motor, problem solving and total development scores over time, total and percentile AIMS scores at 6 months and independent standing and walking milestones (ilr model p-value: </p
Merging Asynchronous Sounds into Synchronous Voices: Articulating an ethics of practice through the making of the <i>Adow ne Domaget 2020 KKK</i> radio program in the time of pandemic
No full textWhen the COVID-19 pandemic halted the world in March 2020, it exacerbated the “falling away” of strongholds and support systems in society and revealed the precarious conditions entrenched in capital accumulation. Attributed to the creative desire for innovation in finding new ways to make sense of our world, creating new connections, and carving a space for the performative body to “appear” and “occupy” amidst isolation and distancing, artists and creatives have been among the first to respond to the vulnerabilities that the pandemic exposed and amplified in our lives.The present work emerges from this unique context of disruption and production.This PhD manuscript consists of two components: First, a creative project presented here with an audio-visual documentation, entitled Adow ne Domaget 2020 KKK: Kuwento, Kultura, at Kalusugan sa Katutubong Komunidad (Dumagat Day 2020 KKK: Stories, Culture, and Health in Indigenous Communities). This was a radio program made in collaboration with the Dumagat Indigenous Peoples community in Dingalan, Aurora, Philippines, and the Aurora Collective of Aurora Artist Residency Program and Space (AARPS), and it was broadcasted from May to June 2020 on the community radio station Radyo Kaedup in Dingalan, Aurora Province, Philippines and the Adow ne Domaget and AARPS YouTube Channels. The second component is a reflexive and experiential exegesis that provides a detailed account of the concept, creation, and analysis of the creative and curatorial process for the radio program. An audio-visual documentation of this PhD project can be accessed here: https://rosellepineda.wixsite.com/rpinedaphdThe production of the radio program amidst the COVID-19 pandemic involved making critical ethical decisions concerning collaborative community-based work that was conducted remotely and asynchronously. This incited deep reflections on the concepts of voice, relationships, and gathering in creative practices that are anchored on community engagement and collective making. From these ruminations, I ask the following questions: how might we reconsider an “ethics of practice” in creative engagements centred on community work? How can “ethical response” be shaped in creative pursuits that are constantly evolving, continuous, and enduring? How can an “ethics of relations” be understood in creative pursuits that are grounded in collaborative and collective work? And how can stories, story construction or storying, and storytelling aid in elucidating, materialising, and demonstrating this reconsidered ethics of practice?Presented as practice-led research, this PhD work utilises three modes of critical reflection to explore the research questions at hand: critical storying, critical conversations, and critical storytelling. Critical storying centres on tracing the author’s personal experiences and previous creative works that informed the making of both the radio program and this exegetical writing. Critical conversation incorporates the voice of the Aurora Collective in analysing the process, ethical considerations, and community implications of making the radio program. Finally, critical storytelling focuses on the modes of narration, particularly experimental storytelling, in presenting the complex ethical considerations and responses that arise in collaborative and collective making settings, especially in times of crises.Using the aforementioned method, this work explores an onto-epistemology of ethical engagement and relations that is based on fluidity, care, response-ability, and responsibility, in creative practices involving collaborative making with communities and collectives.The proposals presented in this work are deemed to have significant implications for the advancement of knowledge and practice in the fields of community arts, cultural work, and community engagement, as well as for the broader discourse on ethics.</p
Developing High-Performance Sodium Metal Batteries by Advanced Interface Engineering
No full textThe abstract for this item has not been populated.</p
Proceedings of the 2025 Resource Operators Conference
No full textProceedings of the 2025 Resource Operators Conference. All papers in these proceedings are peer reviewed. ISBN (ebook): 978-1-74128-409-6 ISBN (paperback): 978-1-74128-410-2.</p
The Effects of Conformational Sampling and QM Region Size in QM/MM Simulations: An Adaptive QM/MM Study With Model Systems
No full textMolecular properties in combined quantum mechanics and molecular mechanics (QM/MM) simulations have been shown to be dependent on the size of the quantum mechanical (QM) region and the amount of conformational sampling. Previous studies have largely focused on enzymatic systems, which have made it difficult to distinguish the effects of QM region size and conformational sampling from other factors including QM-MM boundary artifacts and the boundary effects. This study uses the difference-based adaptive solvation QM/MM method to investigate the tautomerization reactions of alanine and aspartate in explicit solvent. The choice of computationally tractable systems enables the decoupling of QM region size effects from other factors and a direct comparison of free energy surfaces with potential energy surfaces (PESs). The results show that (1) it is crucial to properly account for thermal fluctuations along the reaction pathways, and (2) free energy surfaces converge rapidly with increasing QM region size, whereas charge transfer requires a slightly larger QM region to achieve convergence. These findings are expected to guide future studies of enzymatic systems and other complex systems where QM/MM methods are applied.</p