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Clinical vs. statistical significance: considerations for clinical laboratories
No full textAmongst the main perspectives when evaluating the results of medical studies are statistical significance (following formal statistical testing) and clinical significance. While statistical significance shows that a factor's observed effect on the study results is unlikely (for a given alpha) to be due to chance, effect size shows that the factor's effect is substantial enough to be clinically useful. The essence of statistical significance is "negative" - that the effect of a factor under study probably did not happen by chance. In contrast, effect size and clinical significance evaluate whether a clinically "positive" effect of a factor is effective and cost-effective. Medical diagnoses and treatments should never be based on the results of a single study. Results from numerous well-designed studies performed in different circumstances are needed, focusing on the magnitude of the effects observed and their relevance to the medical matters being studied rather than on the p-values. This paper discusses statistical inference and its relevance to clinical importance of quantitative testing in clinical laboratories. To achieve this, we first pose questions focusing on fundamental statistical concepts and their relationship to clinical significance. The paper also aims to provide examples of using the methodological approaches of superiority, equivalence, non-inferiority, and inferiority studies in clinical laboratories, which can be used in evidence-based decision-making processes for laboratory professionals.</p
Understanding the Genetics of the Outer Subventricular Zone as a Primer for Gyrification
No full textThe mechanisms that regulate gyrification in some species but not in others have been the subject of investigation for decades. To date, numerous theories and perspectives have been proposed to explain how the cerebral cortex acquires its characteristic folds. It is now generally accepted that cortical gyrification is driven by tightly regulatory mechanisms governing neural progenitor cell proliferation, differentiation, and neuronal migration. Although these developmental processes are broadly conserved between gyrencephalic and lissencephalic species, spatiotemporal differences in gene expression and the regulation of these processes result in striking differences to the topographical architecture of the cerebral cortex. The outer subventricular zone (oSVZ) is an expanded germinal layer in the brain that increases significantly in size at the onset of cortical folding. This layer is a hallmark of gyrencephalic development, rich in two populations of basal progenitor cells: basal radial glial cells (bRGCs) and basal intermediate progenitor cells (bIPCs). In the gyrencephalic brain, these basal progenitors have greater proliferative capacity. Through successive proliferative mitoses, they generate vast numbers of post-mitotic neurons that populate the cortical plate (CP) and promote cortical expansion. In contrast, the oSVZ is comparatively thinner in lissencephalic species, with sparse bRGCs and limited capacity for proliferative divisions. Understanding these mechanisms and differences is critical for elucidating how gyrification is regulated. Beyond identifying differential gene expression patterns, analysing the expression dynamics of key candidate genes offers a powerful approach to uncovering their functional roles during cortical development.The overall aim of this thesis was to determine the genetic and cellular mechanisms that drive cortical folding, with a particular focus on the role of bRGCs and their transcriptional regulation within the oSVZ. This thesis therefore sought to identify differentially expressed genes (DEGs) in the oSVZ correlating to the coronal gyrus (CG) and suprasylvian sulcus (SSS) at the onset and middle of gyrification, and to select candidate DEGs for follow up investigation, including a functional genetic manipulation in ferret neural progenitor cells.To investigate the genetic drivers of cortical folding, it is essential to determine differences in gene expression in the oSVZ niche, which includes bRGCs, and to understand these differences throughout cortical development and folding using clear and reproducible methods. In Chapter 2, SPIA paired-end RNA sequencing (RNA-Seq) was performed in the oSVZ beneath the CG and SSS at the onset (P5) and middle (P15) or cortical folding in the ferret. The data revealed several DEGs between the CG and SSS regions at the onset of folding. Additionally, several DEGs were identified in each region from the onset to the middle of cortical folding. Gene ontology and KEGG pathway analyses using DEG lists successfully identified novel biological processes and pathways enriched between the CG and SSS at the onset, and within each region during gyrification. Furthermore, candidate genes identified through literature review were cross-referenced with the RNA-Seq data to determine their expression patterns in the analysed samples and ages. Consistent with the literature, several of these genes were also differentially expressed between the CG and SSS oSVZ at the onset of gyrification. Building on the results of Chapter 2, ten genes were selected for further mRNA and protein level validation: (1) SOX9, (2) FOXM1, (3) FOXC1, (4) GLI1, (5) PI4KB, (6) TUBA4A, (7) AJAP1, (8) PRUNE1, (9) SEMA3D, and (10) STAT3. In Chapter 3, quantitative reverse transcription polymerase chain reaction (RT-qPCR) was performed on remaining P5 and P15 RNA obtained in Chapter 2 to validate the RNA-Seq results for a subset of candidate genes. To further expand on these findings, immunofluorescence staining was performed on a subset of these targets (SOX9, FOXM1, FOXC1, GLI1, and pSTAT3) in the ferret at neurodevelopmental stages encompassing oSVZ genesis (E34), expansion (E38-P2), gyrification onset (P5), middle (P15), and advanced stages of gyrification (P25). The data revealed that most expression differences observed in Chapter 2 were consistent with the RT-qPCR results. Additionally, the data revealed that SOX9 and pSTAT3 were differentially expressed in the oSVZ as early as E34, potentially priming the cortex for gyral and sulcal formation. The results also indicated that FOXM1 was significantly upregulated in the CG oSVZ compared to the SSS at the onset of cortical folding. Based on these findings, FOXM1 was selected as a prime candidate for further experimentation. In Chapter 4, a bioinformatic investigation into FOXM1 focussed on a unique transcript variant comprising an exon proposed to regulate primate cortical folding. The aim was to determine whether this unique exon sequence was found in FOXM1 transcripts of other species, including both gyrencephalic and lissencephalic species, and to assess the conservation of the remaining coding sequence of FOXM1. Using protein, nucleotide, and translated nucleotide BLAST across three databases, it was found that human FOXM1 exon 9 was not present in all other primates, questioning its necessity for gyrification. Furthermore, a multiple sequence alignment of FOXM1 found that the remaining gene sequence was 99% conserved across multiple species, irrespective of gyrencephaly. Lastly, Chapter 5 aimed to generate and characterise a population of ferret neural progenitor cells for genetic manipulation and to perform a functional assessment of FOXM1 in these cells. A previous study showed that the inclusion of exon 9 in the lissencephalic mouse brain led to the formation of cortical folds, suggesting that FOXM1 containing exon 9 may act as a primate-specific cortical folding gene. However, given the findings in Chapter 4 - that exon 9 is not present in other gyrencephalic species – and contrasting literature suggesting that this transcript variant is transcriptionally inactive, further investigation was needed. This study found that exon 9 may influence mRNA and protein-level expression of key neurodevelopmental markers in ferret neural progenitor cells suggesting it may have a regulatory role in the processes involved in cortical folding. Overall, this thesis identified novel DEGs and pathways within the oSVZ that are associated with the location and development of the CG and SSS in the gyrencephalic ferret brain. Additionally, the functional investigation of the candidate gene FOXM1 highlighted the complexity and nuances of gene regulation during cortical development. Collectively, the findings support the notion that region-dependant differences in gene expression are fundamental to the development of the cerebral cortex and have generated a valuable database of DEGs that may act as early determinants or priming factors in the formation of gyri and sulci.</p
Feasibility Assessment of an Optically Powered Digital Retinal Prosthesis Architecture for Retinal Ganglion Cell Stimulation
No full textClinical trials previously demonstrated the notable capacity to elicit visual percepts in individuals with visual impairments caused by retinal diseases by electrically stimulating the remaining neurons on the retina. However, these implants restored very limited visual acuity and required transcutaneous cables traversing the eyeball, leading to reduced reliability and complex surgery with high postoperative infection risks. To overcome the limitations imposed by cables, a retinal implant architecture in which near-infrared illumination carries both power and data through the pupil to a digital stimulation controller is presented. A high efficiency multi-junction photovoltaic cell transduces the optical power to a CMOS stimulator capable of delivering flexible interleaved sequential stimulation through a diamond microelectrode array. To demonstrate the capacity to elicit a neural response with this approach while complying with the optical irradiance limit at the pupil, fluorescence imaging with a calcium indicator is used on a degenerate rat retina. The power delivered by the laser at the permissible irradiance of 4 mW/mm2 at 850 nm is shown to be sufficient to both power the stimulator ASIC and elicit a response in retinal ganglion cells (RGCs), with the ability to generate of up to 35 000 pulses per second at the average stimulation threshold. This confirms the feasibility of generating a response in RGCs with an infrared-powered digital architecture capable of delivering complex sequential stimulation patterns at high repetition rates, albeit with some limitations.</p
An Aesthetic of Matters of Concern
No full textA phenomenological video exploring the aesthetic of the urban traffic in Ho Chi Minh CityMost traffic research focuses on the technological and physical infrastructure of urban traffic systems, which is only a partial picture of the dimensions that make up a traffic system. Other important dimensions, such as human feelings, human values and emotions, belief systems, future goals, past events and more are important fundamental elements in traffic. Traffic users often subconsciously react to such felt atmospheric and affective dimensions, making these aspects at least as important as the physical components, and perhaps even more so. Atmosphere and affect – present in all traffic systems, but especially in Vietnam’s traffic systems – are fundamental to how we navigate our way through these landscapes, but because these dimensions are ‘fuzzy,’ and difficult to measure or quantify using traditional quantitative research methods, they are often overlooked in place of the myth of accuracy that comes with quantifiable numbers.This video aims to create a sensory and affective experience reflective of the aesthetic nature of the HCMC traffic system, bringing to the forefront the rhythmic interplay, the relationalities, and the atmospheric conditions that are uniquely characteristic of the HCMC urban traffic experience. This phenomenological approach to the study of traffic attempts to approach the phenomenon on its own terms and using its own unique language.</p
Portfolio of live radio interviews with politicians ahead of the 2025 Australian federal election
No full textBackground: The broadcast political interview has long been considered core to journalism’s role in democracy (Feldman, 2022; McNair, 2000). However, its effectiveness in holding politicians to account has waned in the digital age (Jewell, 2018). Community radio – which remains a popular source of news for many Australians – offers a space for experimenting with an approach to political interviewing that contributes to an informed citizenry, but avoids some of the tropes of political journalism that deters audiences (Ben-Porath, 2010). This portfolio, comprising four live long-form radio interviews with 2025 Australian election candidates, seeks to fill a gap in understanding about the democratic value of Australian community radio (van Vuuren, 2006). It responds to the question: “How can political interviews on community radio best serve listeners and contribute to an informed citizenry?” Contribution: ‘Meet the candidates’ is a series of interviews with politicians ahead of the 2025 Australian federal election, broadcast live on Melbourne radio station Triple R between February-May, 2025. Informed by my 11 years broadcasting experience, it aimed to engage politicians through hybrid interviews (Hutchby, 2017) involving both pointed policy questions and those of a more personal nature. It also involved live interactions with a text line, with listeners invited to pose questions to the interviewees, and one of the interviews took the form of a community forum recorded in front of a live audience. This added to the interviews’ democratic value by involving community radio’s ‘listening publics’ (Lacey, 2013) in policy discussions. Significance: Triple R is Australia’s largest community radio station, with approximately one million monthly listeners (McNair, 2019) Triple R’s Programming Coordinator Bec Hornsby endorsed the interviews and provided feedback (peer review) on each of them. Hornsby attests to the interviews’ significance for Triple R’s election coverage, and to the quality and popularity of my radio show (Appendix B). Community radio can struggle to be recognised for quality political journalism, so it was significant that I managed to interview and extract new information from high-profile politicians. Endorsements from individual listeners and civil society groups such as Save Our Arts (Appendix A, C) further attests to the interviews’ role in the public sphere.</p
Changes in Attention Levels While Driving a Car Estimated Using Modelling Techniques with Features of Oculo-Motors
No full textChanges in attention levels while driving a car were estimated using a modelling technique involving pupillary changes and the frequency of saccades of 11 drivers. The driving route used in the experiment consisted of 19 sections of road divided into 5 groups: university campus, left turn, straight, right turn, and roundabout. The sections of road with posted speed limits were divided into 6 conditional states, and model parameters were estimated by assuming transitions across the states. The estimated model parameters were used to examine changes in the level of attention resources used during each section of driving. The results of a comparison of attention resources by section showed a significant decrease, in the following order: straight and roundabout, within campus, left turn and right turn. In addition, the relationship between NASA-TLX was evaluated after driving and attention resources were examined, and a significant correlation with the factor for “difficulty” was confirm ed. The relationship between the confidence interval of the change in attention resources and the factor for “mental demand” was also confirmed.</p
Mapping the Fashion Entrepreneurship Ecosystem in Saudi Arabia: Impacts on Entrepreneurial Orientation and Business Performance of Micro, Small, and Medium Enterprises
No full textThis study investigates the influence of the fashion entrepreneurship ecosystem (FEE) on entrepreneurial orientation (EO) and business performance (BP) within fashion micro, small, and medium enterprises (MSMEs) in Saudi Arabia. Drawing on the Resource-Based View (RBV) theory (Barney, 1991), EO, defined through innovativeness, proactiveness, and risk-taking (Lumpkin & Dess, 2015), is treated as a core intangible resource that mediates the relationship between external ecosystem elements and firm success (Sarsiti, 2024). The FEE is conceptualised as a dynamic interplay of domains, including finance, education, policy, market, culture, and support (Isenberg, 2011), each contributing to entrepreneurial development in line with Saudi Arabia’s Vision 2030 (Nurunnabi, 2017). While prior studies have explored these domains separately or in different sectors (Spigel, 2017), no research has integrated them in the specific context of Saudi fashion MSMEs.Saudi fashion enterprises represent a growing but under-researched segment within the creative economy, with the sector projected to grow by 11.6% annually and reach a value of USD 7.57 billion by 2029 (Statista, 2024). These businesses are often led by women and face unique challenges, including limited access to finance, weak entrepreneurial education, and global market barriers (Alshibani et al., 2024; Maghrabi & Abalkail, 2024). This study addresses this critical gap by offering a context-specific analysis of how FEE factors impact EO and BP, thereby supporting policy efforts to diversify the economy and strengthen the creative sector (Almuzel & Anderson, 2020).This thesis comprises two sequentially linked studies using a mixed-methods explanatory design (Creswell, 2017). Study 1 employed quantitative analysis (PLS-SEM) to test the direct and mediating effects of FEE on EO and BP. Study 2 involved thematic qualitative interviews with fashion entrepreneurs and ecosystem stakeholders to explain and contextualise these quantitative findings. This integration enables a comprehensive understanding of how systemic factors influence entrepreneurial success, particularly when outcomes diverge from expectations (Dionysus & Arifin, 2020). The findings offer theoretical contributions to the entrepreneurship literature and practical insights into policy reform, ecosystem development, and educational innovation in Saudi Arabia.Study 1ParticipantsThe participants in this study included 223 fashion MSMEs operating in Saudi Arabia. The sample primarily consisted of female participants (91%), with 67.3% holding a bachelor’s degree. Most participants (50.7%) studied fashion, while 36.3% attended business courses. Approximately 44.4% of businesses were established between 2017 and 2020. Most businesses (94.2%) were microenterprises in size.MethodsThe survey instrument measured FEE, EO, and BP using validated frameworks. FEE was assessed using the Global Entrepreneurship Monitor (GEM) National Expert Survey (NES), which evaluates core ecosystem factors: finance, policy, market, culture, social norms, entrepreneurial education, talent, and support. EO was measured using Covin and Slevin's (1989) three core components: innovativeness, proactiveness, and risk-taking. BP was assessed using five key indicators: ROI, sales increase, customer satisfaction, employee satisfaction, and overall firm performance. This approach aligns with prior research on performance evaluations (Murphy et al., 1996; Hult et al., 2008). Financial and non-financial metrics provide a comprehensive view of business success (Harter et al., 2002; Wong & Low, 2013).Participants were contacted via email and invited to participate in the study. After providing consent, participants accessed the online survey through Qualtrics. The survey questions were compulsory, ensuring that no data points were lost. Data analysis involved several key steps using IBM SPSS and SmartPLS software. Measurement reliability and validity were assessed using Cronbach’s alpha, composite reliability (CR), and average variance extracted (AVE) values. The measurement model was evaluated for internal consistency (Cronbach’s alpha > 0.70), composite reliability (CR > 0.70), and discriminant validity using the Fornell-Larcker criterion and the heterotrait-monotrait (HTMT) ratio. Structural equation modelling was used to assess the direct and indirect effects. Path coefficients, R-squared (R²) values, and bootstrapping methods were used to confirm the significance and model fit.ResultsDirect Impact of FEE on EO: Path analysis revealed a significant positive effect of FEE on EO (β = 0.308, t = 4.145, p Direct Impact of FEE on BP: A significant but smaller positive effect of FEE on BP was observed (β = 0.149, t = 2.113, p = 0.035). The R² value for BP was 0.286, indicating that FEE explained 28.6% of the variance in BP. This suggests that the entrepreneurial ecosystem supports business growth and performance, although other factors may also contribute.Direct Impact of EO on BP: EO had a strong positive influence on BP (β = 0.469, t = 8.078, p Mediating Role of EO: EO partially mediated the relationship between FEE and BP. The direct effect of FEE on BP was β = 0.149 (p Model Fit and Predictive Relevance: The model demonstrated moderate predictive relevance for BP (Q² = 0.176) and weak predictive relevance for EO (Q² = 0.045). All constructs demonstrated high factor loadings (>0.70), satisfactory composite reliability (>0.70), and discriminant validity. Path analysis confirmed that the model fit the data well..Study 2This qualitative study is based on 15 interviews with key stakeholders in the Saudi fashion industry. It focuses on mapping and exploring the current landscape of the Saudi FEE and how each domain influences EO and BP. Based on inductive thematic analysis, Study 2 revealed several influential ecosystem factors shaping EO and BP: most fashion entrepreneurs relied on informal sources, such as personal savings or family loans, due to limited access to venture capital or incubator funding. The Social Development Bank was a key source of accessible loans, but procedural complexities, limited financial literacy, and cultural/institutional biases especially against women restricted access to broader financial support. Access to finance directly enhances innovation, sustainability practices, and risk-taking (Alshibani et al., 2024; Alsaiari, 2022; Adam, 2024).While entrepreneurship is culturally encouraged in Saudi Arabia, fashion as a profession faces lingering stigma, particularly tailoring, which is viewed as a low-status profession. Regional and religious values shape design preferences and business models, and fear of failure discourages risk-taking, especially among women, due to societal pressure and a preference for government jobs (Alzahrani et al., 2015, Fridhi, 2020, Elshaer & Sobaih, 2022). The study found a significant mismatch between the available incubators and the specific needs of fashion startups. Most support structures are designed for tech startups and offer irrelevant services, such as software mentorship. Consultants are often competitors, creating trust issues. Entrepreneurs in rural areas also face geographic barriers to support access (Braun & Suoranta, 2024; Kazhenov, 2023; Nana et al., 2021).While the government has expanded fashion programs and scholarships, participants reported limited institutional support for starting businesses. Overseas universities offer stronger entrepreneurship support. Local institutions lack practical, fashion-specific business training, structured entrepreneurial curricula, and access to industry professionals (Alshebami, 2022; Raju & Singh, 2023; Lang & Liu, 2019). The evidence from this study supports the idea that variations in entrepreneurial performance in the Saudi fashion sector depend not only on access to resources but also on the entrepreneur's ability to transform these assets into a competitive edge. This transformation aligns with the RBV’s focus on resource deployment as strategic behaviour (Wernerfelt, 1984) and is supported by research highlighting EO as a critical mediator of resource effectiveness (Dionysus & Arifin, 2020; Ferreira et al., 2011).</p
Formalising the Informal? Investigating the Potential of Repurposed Public Space as Intangible Cultural Heritage
No full textThis thesis examines how informal, embodied adaptations of public space shape urban culture, focusing on Melbourne’s Flinders Precinct. Through everyday acts of spatial appropriation – such as gathering, resting, or socialising on steps, ledges, bollards, and edges – people continuously negotiate, contest, and redefine urban spaces, contributing to the city’s public culture. These socio-spatial negotiations, ranging from mundane to intentional, influence how public spaces function and are imagined. Through this process, individuals assert spatial rights and reassign cultural meaning to the public realm. However, these adaptive practices do not occur in isolation; they emerge in response to the built environment and its governance, which manifests through both physical form and spatial controls such as policy, regulation, and securitisation. This interplay reveals the generative tensions between formal governance and the lived realities of urban public life.This research critically explores how these adaptive spatial negotiations shape the Flinders Precinct, while also examining how municipal governance frameworks value and manage this form of public culture. It considers the role of heritage as an actor in these processes – an institutional framework often critiqued for its rigid delineation between tangible and intangible culture. In doing so, this thesis contributes to the conceptual expansion of heritage discourse, arguing for an approach that moves beyond preservationist frameworks to engage with the embodied, everyday practices of public space as a form of lived, urban culture. Findings reveal a governance paradox: while informal spatial practices contribute to the urban imaginary and socio-spatial justice, their ephemeral nature often leaves them vulnerable to competing policy agendas. However, any effort to formally recognise these practices needs to be cautious not to undermine their adaptive, fluid and even, ordinary nature.This study employs a cultural mapping methodology, integrating qualitative, mixed-methods research – including ethnographic participant observation, interviews, and policy analysis – to ‘map’ the public culture of the Flinders Precinct. This approach captures the lived experience of informal spatial adaptation and examines how these practices intersect with heritage management frameworks. Melbourne provides a rich and dynamic urban landscape in which to explore these questions, as a city globally recognised for its cultural vibrancy yet constrained by governance frameworks that struggle to account for embodied spatial practices. The Flinders Precinct in particular, serves as a key site of study due to its civic and cultural significance: it contains Flinders Street Station, where the station steps function as a grandstand overlooking the city’s busiest intersection; Federation Square, Melbourne’s main public square, which operates under a contested public-private management model; and Hosier Lane, a prominent street-art destination embedded within the city’s tourism identity. These three locations within the precinct serve as my case study sites, along with the interstitial spaces between them that make up the precinct.This research makes three key contributions. Theoretically, it advances the integration of spatial and affective perspectives into heritage discourse, arguing for an expanded framework that embraces embodied cultural practices as central to urban identity. Empirically, it provides an in-depth case study of Melbourne’s Flinders Precinct, documenting the interplay between public space adaptation and heritage governance. Methodologically, it introduces a cultural mapping approach that highlights the limitations of conventional heritage inventories in capturing embodied urban cultural practices.</p
Topology Optimisation for Enhanced Buckling Resistance in Continuum Structures
No full textTopology optimisation has gained significant attention due to its ability to design efficient structures with minimal material usage. Buckling is a critical factor that should be considered in optimisation algorithms to guarantee the stability of designed structures. However, topology optimisation that incorporates buckling resistance has remained challenging in recent decades, primarily due to issues related to inaccuracies in buckling analysis and the phenomenon of mode switching. This thesis systematically addresses these challenges through a comprehensive investigation into their underlying mechanisms and the development of robust algorithms for the topology optimisation of structures designed to resist buckling.First, a topology optimisation approach that integrates buckling constraints into the bi-directional evolutionary structural optimisation (BESO) method is proposed. Compared to density-based topology optimisation algorithms, which often encounter pseudo buckling modes in intermediate-density elements, the proposed method offers an advantage by using only two discrete states for design variables, thereby effectively alleviating the numerical issues associated with these pseudo modes. The Kreisselmeier-Steinhauser aggregation function (KS function) is introduced to aggregate multiple buckling constraints into a differentiable form. An augmented Lagrangian multiplier method is developed to integrate buckling constraints into the objective function, ensuring computational stability. Furthermore, a modified design variable update scheme enables precise control of the evolutionary rate after reaching the target volume fraction. The effectiveness of the buckling-constrained BESO method is validated by four topology optimisation design examples, demonstrating enhanced structural stability with only a modest compliance increment.Second, while the discrete optimisation algorithm can mitigate the occurrence of pseudo buckling modes, achieving their complete elimination remains a challenge. The mechanism underlying pseudo buckling modes is comprehensively investigated. The research reveals that these modes stem from stress singularities in the finite element analysis of multi-density elements. To facilitate the implementation of stress relaxation functions that avoid singularities, a linear material interpolation scheme is introduced to the buckling optimisation problem. This linear material model offers several advantages: it eliminates the need for penalisation schemes and penalty values, and enables straightforward sensitivity analysis. The buckling optimisation algorithm is subsequently developed based on the floating projection topology optimisation (FPTO) method, effectively driving intermediate elements towards definitive 0/1 solutions. By employing the developed method, the objective of maximising the critical buckling load factor (BLF) is successfully achieved, with four design examples demonstrating significant improvements over existing algorithms.Third, the proposed optimisation approach is further developed to address the issues of incorrect buckling analyses and high dependency on parameter variations. This study delves into the underexplored phenomenon of ‘spurious localised buckling modes’, which can occur across all densities, including solid elements. A novel local stress relief strategy is developed to eliminate these spurious modes. Additionally, an innovative problem reformulation is introduced for buckling-constrained optimisation, which decouples the critical BLF from the aggregation function. This reformulation effectively prevents the influence of aggregation parameters on the accuracy of the critical BLF approximation and enhances optimisation stability by avoiding mode switching. The effectiveness of the proposed algorithm is validated through both BLF maximisation and buckling-constrained problems. A series of 2D and 3D examples demonstrate that the proposed algorithm requires minimal parameter tuning across various challenging cases. It ensures stable convergence and attains satisfactory objective values, while accurately fulfilling the constraints.Finally, the buckling optimisation algorithm is extended to accommodate design-dependent problems. A mixed formulation is employed to handle three different types of elements: incompressible hydrostatic fluid, elastic solid, and air. A straightforward implementation method is proposed to identify the exchangeable domains for these three element types. The buckling analysis within the mixed formulation is systematically investigated, and the corresponding sensitivities are derived. The proposed algorithm allows for a large bulk modulus value in fluid simulation without compromising numerical stability. The proposed algorithm is tested across a variety of cases, demonstrating its ability to design underwater structures with enhanced buckling resistance.This thesis makes significant theoretical contributions to the field of topology optimisation by systematically resolving fundamental challenges, including the mechanisms behind pseudo buckling modes, spurious localised modes, mode switching, and numerical instability. These theoretical advancements have paved the way for the development of robust algorithms with strong potential for practical applications, ranging from traditional solid mechanics structures to specialised underwater designs.</p
1.76 Million Down Under
No full textFarm dams are the major source of water for livestock and crop irrigation in agricultural landscapes around Australia. With increasing global demand for reliable freshwater supplies, farm dams are expanding rapidly often dominating the cumulative surface area of continental waters. Further, well-managed farm dams are pivotal assets for water management, food security, and ecological sustainability. Yet, overlooked for centuries, these ecosystems remain unmanaged releasing large amounts of GHG like carbon dioxide and methane. This research explores how farm dams can be transformed to rewarding ecosystems by adopting nature-based solutions. Looking ahead, as the climate change intensifies and agricultural water needs rise, the sustainable management of farm dams will become increasingly vital for a resilient and productive future.</p