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Developing learning health system capabilities in the UK National Health Service - using asthma as an exemplar
Get PDFAsthma is a common condition responsible for substantial morbidity and societal impacts, much of which are potentially preventable. This condition, therefore, serve as useful exemplar to investigate the opportunities for developing health infrastructures that allow continuous cycles of improvement. The United Kingdom’s (UK’s) mature electronic health records infrastructure offers considerable opportunity to improve outcomes for people with asthma through the creation of a Learning Health System (LHS). The core idea in an LHS is to use the continuous streams of data emerging as a by-product of clinical care to inform and support policy decisions, organisation and delivery of healthcare and the personalisation of care. This was demonstrated during the recent COVID-19 pandemic when data from across the health ecosystem were harvested and analysed in near real-time to inform decision relating to public policy, public health and clinical care. In this thesis, I reflect on the progress made to advance capabilities to building LHS in the NHS for asthma and summarise outstanding challenges by critically considering eight papers that I first-authored between November 2014 and June 2024.
I begin this thesis with a brief overview of why asthma was used as an exemplar and how LHS has the potential to curb adverse outcomes of asthma and improve health in people with asthma. The concept of Learning Healthcare System had emanated from healthcare. Recognising that health is also shaped by wider determinants such as housing conditions and air pollution, Prof Aziz Sheikh proposed the term Learning Health System to encompass factors beyond healthcare alone. In this thesis, I adopt the definition of LHS as proposed by Prof Aziz Sheikh. Then I proceed to relevant epidemiological and health services research studies and LHS literature that predates and informs my own research and publications. Towards creating an LHS for asthma, I am guided by the four priority areas identified by Health Foundation and Health Data Research UK: i) learning from data, ii) harnessing technology, iii) learning communities and iv) implementing and evaluating improvements to services.
Next, I focus on my research, describing the studies I was involved in. In that chapter I describe three epidemiological and health services research studies and a qualitative study on health information systems I was involved in, which underpinned my submitted publications. For these four studies, I describe my involvement in the study, background to the study, the aims and objectives, design and methods used, implication of the findings and dissemination of findings.
My first paper provided the first evaluation of primary care clinical codes on asthma and allergies as was used in two million GP consultations in Scotland. My second paper is a protocol, which, for the first time, listed the routine and administrative datasets across the four nations of UK, for finding epidemiology and burden of asthma and the methods used to analyse these. In my third paper, I used those datasets to report the first comprehensive asthma burden estimates in the UK. In the absence of linked and longitudinal data, my fourth paper used cross-sectional data to create, for the first time, a population pyramid of asthma morbidity in Scotland. I found that a small proportion of people with asthma make disproportionate use of hospital-based asthma services. The fifth paper described, for the first time, profile of those admitted in paediatric intensive care in England for asthma, with patterns of healthcare utilisation and outcomes.
These exercises involved working with different data custodians across geography, data harmonisation issues and significant time lags between care provision and access to the data. Thus, to explore the barriers and facilitators in utilising electronic health records in near-real time across information systems, my sixth paper was a qualitative study based on interviews of stakeholders and data users in Scotland, which has rich data assets. The next study focused on creating LHS capability and investigating asthma modifiable factors so that targeted interventions could be provided in near-real time. The seventh paper was one of the first publications that analysed asthma modifiable factors that might explain the reduced risk of asthma hospitalisations during the COVID-19 pandemic. This PhD culminated in the development and deployment of a near-real time asthma dashboard designed for use in UK primary care. Using routinely collected data from the Oxford-RCGP RSC, the tool provides weekly feedback on asthma epidemiology, modifiable risk factors, and exacerbations at practice level, benchmarked against network averages. The dashboard operationalises key features of an LHS by enabling a timely, data-informed decision-making tool to support local quality improvement.
This is followed by my reflections in the next chapter, on the findings of my submitted papers, noting how individually and collectively, they contributed to the priority areas for creating an LHS. They have been presented under: i) learning from data: clinical codes, compiling and linking datasets for comprehensive understanding of the asthma burden, focusing on people with high health needs, children admitted to paediatric intensive care, potentially modifiable risk factors for asthma exacerbations, asthma dashboard as a quality improvement tool in asthma care, data fitness for research, data lifecycle approach, accessing data via single trusted research environment with metadata; ii) harnessing technology: overcoming technological roadblocks in real-time data, data integration across systems, modernising infrastructure, call for tech-savvy workforce, data virtualisation, asthma dashboard as an integrated visualisation; iii) learning communities: building collaboration to overcome data challenges, collaboration at national level; and iv) implementing and evaluating improvements to services through real-time monitoring.
After describing my contributions, I attempt an interpretation of my work in the context of the wider literature on asthma and LHS and identify alignments and distinctions. I discuss that by focusing on the role of LHS, my papers and review of the literature offer insights into how LHS capability could be built in the NHS to improve asthma outcomes.
I assess the strengths and limitations of my published work and implication of my findings for the existing literature on LHS. I conclude, that to improve asthma outcomes, an LHS approach is a potential solution. My contribution spans i) ‘practice to data’ cycle of LHS by listing the clinical codes and datasets on asthma in the UK nations, ii) ‘data to knowledge’ cycle by providing a) comprehensive estimates of asthma epidemiology, healthcare utilisation and outcomes at every UK-nation level and UK-wide, which can be used for baseline estimates for future studies, b) identification of potentially modifiable factors for asthma exacerbations, c) knowledge on barriers and facilitators that can enable real-time access to data; and iii) beginning of the ‘knowledge to practice’ cycle by deploying an asthma dashboard in RCGP RSC, which now needs promotion for regular usage and evaluation.
My reflections on my research journey involved navigating complex health data ecosystems to investigate how routine data can inform better asthma care. My early studies revealed limitations in coding and data quality, while later work identified modifiable risks and inequalities in asthma outcomes. The development of the asthma dashboard marked a turning point, shifting from knowledge generation to deployment in practice. Key lessons included the importance of data curation, stakeholder co-design, and the structural challenges of sustaining learning systems in real-world practice.
My call to action is to realise the potential of a national LHS for asthma - the NHS must move from data collection to action. This involves embedding real-time feedback tools like the Oxford-RCGP RSC asthma dashboard into clinical workflows, improving coding for treatable traits, investing in local quality improvement, and fostering collaborative learning communities. The UK's world-class data infrastructure can, and should, be harnessed to reduce variation and improve outcomes in asthma care
Dealing with complexity in responsive design: thematic mapping and visualization across varied devices
Get PDFLike most digital content, information visualizations and thematic maps are increasingly being accessed from a large variety of devices: different types of smartphones, smartwatches, tablets, laptops, desktop computers, and more. These come with different screen sizes, interaction modalities, and usage scenarios. Responsive design accounts for these various device and usage contexts and ensures that visualizations adapt to remain legible and usable. However, thematic maps pose specific challenges to responsive design, such as inflexible aspect ratios that do not easily adapt to varying screen dimensions, or densely clustered visual elements in urban areas becoming illegible at smaller scales. While recent work has proposed a variety of approaches and design strategies for responsive visualization, there is still a lack of techniques suitable for thematic maps and other visualization types with similarly complex layout constraints.
Building on prior work in responsive visualization and mobile mapping, this thesis uses a combination of qualitative research and research-through-design to explore, identify, and develop strategies and techniques for responsive thematic mapping and visualization. Based on expert interviews and design workshops with visualization practitioners, the thesis describes challenges and design solutions in responsive thematic mapping, as well as higher-level strategies followed by visualization designers. My studies reveal a strong preference for maintaining conventional thematic map designs across as many screen sizes as possible, and I identify a range of specific design solutions to support this. I then develop and demonstrate a novel technique for responsive thematic maps and other complex visualizations: constraint-based breakpoints allow visualization creators to effectively manage multiple versions of a responsive visualization. Through example visualizations, created using my prototype library and design toolkit, I demonstrate how constraint-based breakpoints offer designers fine-grained control over the displayed visualization design across a wide range of screen sizes. Finally, I examine differing approaches to responsive visualization design and development using Munzner's nested model for visualization design. Across the four levels of the model, I describe considerations in responsive design, highlight existing guidance and tools, and identify opportunities for future research.
Ultimately, this thesis demonstrates that it is both necessary and possible to take a more expansive approach to responsive visualization: the techniques, strategies, and prototypes I present show that responsiveness can be achieved for geographic and other complex visualizations across many different sizes beyond desktop and mobile
The elephant will return to the veldt: narratives of nostalgia and self-continuity in the work of Murakami Haruki
Get PDFScholarship on Haruki Murakami’s oeuvre has noted, with some scepticism,
the prominent role of nostalgia in his narratives of self-discovery in postmodern
Japan. This criticism rests on two assumptions: that nostalgia is a negative
psychological state, and that Murakami’s use of it in his work is therefore
flawed. This thesis, however, argues for a more constructive evaluation of
nostalgia and shows how in the past two decades, Murakami’s use of nostalgia
has evolved into a pivotal mechanism for protagonists to reconstruct their
self-identity and continuity. In his three most recent full-length novels – Colorless Tsukuru Tazaki and His Years of Pilgrimage (2013), Killing
Commendatore (2017), and The City and Its Uncertain Walls (2023) –
nostalgic narratives encourage individuals to reflect on their past with
appreciation, channelling renewed confidence into the present, and facilitating
the rewriting of new self-narratives necessary to address contemporary
existential dilemmas and uncertainties. Driven by nostalgia, this narrative
process not only enables individual self-reconstruction but may also serve as a
reflection on Japan’s postwar tendency to sanitize and obscure war memories
while suppressing individual voices in the pursuit of modernization. As such
this thesis argues that rather than a critical weakness of Murakami’s work, nostalgia, and the identity narratives it produces could be crucial tools for
critically engaging with the legacies of post-war Japan
Branding the nation through Beijing 2022: a semiotic analysis of Olympic sponsorship, national identity, and gender ideologies in Chinese advertising culture
Get PDFThis study investigates how Olympic sponsorships in China serve not only commercial but also ideological functions by constructing national identity and gender ideologies through advertising. While existing literature has extensively addressed the commercial value of sponsorships, there is limited research on how such campaigns symbolically produce meaning, especially in non-Western contexts. Focusing on the 2022 Beijing Winter Olympic Games, this research examines how Chinese consumers interpret Olympic sponsorship advertisements through culturally embedded signs, and how these campaigns construct meanings related to nationalism and gender. Olympic advertising is therefore positioned as a cultural text that can reinforce or challenge dominant ideological narratives.
With a social constructivist paradigm, this qualitative case study combines semiotic textual analysis with focus group interviews. Specifically, the study first conducts a semiotic analysis of two Olympic-themed advertisement videos by Chinese dairy brands Yili and Mengniu. Then, a semiotic analysis was applied to interpret data from focus group discussions, where participants reflected on Beijing 2022, Olympic sponsorship, and related advertising content.
The findings reveal how Olympic sponsorships in China operate as ideological sites. Consumers interpret advertisements through nationalistic and gendered lenses, often reinforcing collective identity or questioning representational norms. Olympic advertising tends to embed official national and cultural symbols to foster patriotic sentiment. Visual narratives commonly include national flags, traditional aesthetics, and iconic athletes, reinforcing a shared imaginary of unity and pride. Participants frequently used pronouns such as “we” and “our”, demonstrating an internalised sense of national belonging. Gender representations in media and ads also followed normative ideals: women were typically associated with beauty and were infantilized, while men symbolised strength and performance. These portrayals were largely accepted but occasionally contested, reflecting tensions between patriarchal norms and emerging feminist perspectives. Media and ads related to Olympic sponsorship emerges as a space where gender and national ideas are both shaped and questioned.
This research contributes to sports marketing, semiotics, and cultural studies by offering an integrated framework for analysing brand communication in ideological contexts. It also highlights the active role of audiences in constructing and negotiating media meaning. Ultimately, the study provides insight into how Olympic sponsorship operates as both corporate branding and socio-political messaging in contemporary China
Multi-omics provide insights into the regulatory network for human germline development
Get PDFPrimordial germ cells (PGCs), the precursors of the human germline, are specified during early embryonic development and will ultimately give rise to sperm and eggs. Recent studies have revealed that humans employ different mechanisms for PGC specification compared with model organisms such as mice. For example, humans uniquely require the transcription factor SOX17 for PGC induction, while mice rely on a different transcription factor Sox2. Despite these species-specific differences and the importance of PGCs for fertility, the regulatory machinery of human PGC remains largely unexplored due to the inaccessibility of early human embryos. To address this knowledge gap, our study leverages a comprehensive multi-omics strategy to systematically characterize the regulatory network guiding human PGC development.
To capture this dynamic process, we curated and integrated an extensive multi- omics dataset encompassing both in vitro PGC-like cell models and in vivo embryonic PGCs. This dataset includes samples of 581 bulk transcriptomes (RNA-seq), 54 chromatin accessibility profiles (ATAC-seq), 45 histone modification profiles (ChIP-seq), and 69 single-cell transcriptomes (scRNA- seq), covering key developmental stages from pluripotent stem cells to migrating PGCs. All data were uniformly processed and assembled into a specialized database, hPGCdb, which serves as a comprehensive atlas of human PGC development. This resource recapitulates the precisely controlled and stepwise transitions of germ cell specification and enables systematic dissection of both intrinsic gene regulation and extrinsic signaling cues underlying the establishment of the germline.
By analyzing this integrated atlas, we identified the key gene expression programs and transcription factors (TFs) that drive human PGC fate at each stage. Expected key regulators such as PRDM1 (BLIMP1), TFAP2C, and SOX17 were prominent, validating our approach, but importantly we also uncovered novel TF candidates. Many of these novel TFs human PGC-specific upregulation accompanied by increased chromatin accessibility, suggesting roles in activating the germ cell program. Integrating the epigenomic data revealed clear evidence of epigenetic priming: even before germline genes are expressed, their promoters and enhancers in pluripotent stem cells are already in an open chromatin state (often with binding of pioneer factors), preparing these loci for rapid activation upon germ cell fate induction. This coordinated
transcriptional activation and chromatin remodeling appears to underlie the initiation of the human germline lineage.
To determine the functional importance of newly identified regulators, we performed loss-of-function experiments using a CRISPR interference (CRISPRi) approach. Among the top novel TF candidates identified from our analysis, SOX4 and TEAD4 were selected for knockdown during the in vitro differentiation of human embryonic stem cells into PGC-like cells. Suppression of either TF led to a significant impairment of PGC formation. These results provide direct evidence that SOX4 and TEAD4 are critical drivers of human germ cell specification, validating the predictive power of our integrative multi- omics strategy in uncovering previously unrecognized germline regulators.
To further elucidate the regulatory network underlying each developmental transition, we leveraged single-cell transcriptomics and advanced gene regulatory network (GRN) modeling. Using the single-cell RNA-seq data, we constructed co-expression networks (via single-cell WGCNA) to identify gene modules associated with germline commitment, and we applied an integrative GRN framework (Dictys) that combines chromatin accessibility with gene expression profiles. These approaches identified not only the known germline regulators but also novel contributors to PGC development, including RNA- binding proteins and signaling pathway components that may modulate post- transcriptional regulation and cell-cell interactions. The resulting networks offer a systems-level view of the gene regulatory hierarchy in hPGC development, revealing how transcription factors, co-factors, and dynamic chromatin states coordinate to control the stepwise differentiation process of the germline lineage.
In addition to intrinsic regulators, we examined the interactions between PGCs and their somatic microenvironment, describing a soma-germline communication network in both in vitro and in vivo contexts. Ligand-receptor analysis discovered that both Syndecan-2 (SDC2) and Laminin A4 (LAMA4) are highly expressed in human PGCs. SDC2 acts as a key receptor, while LAMA4 functions as a critical ligand. Together, they mediate supportive niche signals for PGC specification. Knocking down SDC2 or LAMA4 caused an ~50% reduction in PGC-like cells induction efficiency, confirming their essential roles. Furthermore, we found that NOTCH2 signaling from somatic cells plays a vital role in promoting the later-stage hPGC maturation. Late-hPGCs (which express marker DDX4) uniquely receive NOTCH2 signals from their environment, and
experimentally inducing NOTCH2 activity in early PGC-like cells promoted these cells toward a more advanced, DDX4-positive state. These findings demonstrate that extrinsic cues from the cellular niche fundamentally shape PGC development to ensure proper germline progression in both the early and late stage.
Altogether, this work provides an exceptional multi-omics framework for understanding how human germline fate is established, encompassing both the internal gene regulatory programs and the external signaling interactions that drive PGC development. The comprehensive insights gained highlight a distinct divergence between human and mouse PGC regulatory networks, cautioning against direct inference from animal models. By identifying novel germline regulators and intercellular signals, we not only advance the fundamental understanding of human developmental biology but also create a foundation for translational research. The data and resources generated (including hPGCdb) will facilitate future studies in reproductive biology and regenerative medicine
Power quality detection, testing, and harmonic stability enhancement methods for power electronic-dominated systems
No full textPower electronic devices, which play a pivotal role in energy conversion within renewable
energy systems, have also introduced significant challenges to power quality
and system stability, such as harmonics, voltage sags and resonance instability. For
example, the high switching frequencies of converters generate harmonic distortion,
while their limited fault current contribution hinders effective voltage recovery during
faults, resulting in deeper and more prolonged voltage sags. Furthermore, the
harmonics produced by these devices can trigger resonances and interactions
between the converter and grid, potentially escalating into system-wide instability.
These issues negatively affect the reliability of system operation. Power quality and
system stability issues can significantly disrupt the operation of equipment within
the power system. For instance, voltage sags may lead to equipment malfunctions
or interruptions, adversely affecting industrial processes. Additionally, waveform
distortion caused by harmonics can interfere with the performance of controllers
in low-power and low-cost applications, and the discharge behaviour of capacitors
within converters. This is particularly critical as some controllers rely on zero-crossing
detection for operation, while variations in peak values can influence the voltage ripple
and stress imposed on capacitors, further compromising system reliability.
Therefore, it is essential to investigate the power quality detection, testing and
resonance/harmonic stability analysis to ensure the system operation safety and
reliability. One of the important topics investigated in this thesis is enhancing and
evaluating power quality detection methods, as they play a critical role in ensuring
the effective operation of equipment such as uninterruptible power supplies (UPS)
and reactive power compensators. Additionally, investigating the impact of power
quality issues on equipment performance through fault tolerance testing is crucial
for understanding the vulnerabilities of equipment under varying conditions. Finally,
to better maintain the resonance stability, designing power converters with a high
stability margin, particularly for operation in weak grid environments, is vital from a
power electronics perspective to ensure overall system stability.
In this thesis, an evaluation approach for power quality detection methods is
proposed, incorporating both frequency and time-domain analyses. The results
demonstrate that comparing only the frequency, magnitude, and phase angle that
each detection method extracted is insufficient for a comprehensive assessment. This
integrated framework allows for a more robust comparison of detection techniques,
revealing their respective strengths and limitations. Additionally, a new wavelet is
developed for wavelet transform-based methods, significantly improving the accuracy
of harmonic detection in multi-scale analysis.
Additionally, the malfunction conditions of end-user equipment are investigated
through a comprehensive tolerance test that combines AC voltage sag testing with
excessive DC ripple assessment. The results offer valuable insights into equipment
vulnerability under various disturbance scenarios. Building on this understanding,
a generalised and optimised sensitivity testing method is proposed, based on DC
link voltage prediction. This method significantly reduces the need for repetitive
testing while maintaining high accuracy in reconstructing tolerance curves. Owing
to its time efficiency, the proposed approach can be applied to a wide range of sag
conditions and equipment operating scenarios. It also enables automated generation
of equipment tolerance curves, accounting for various harmonic combinations and
different DC link capacitor sizes in power supply designs. Additionally, the derived
tolerance curves can support the optimal selection of DC link capacitors to meet
specific ripple and ride-through performance requirements.
Finally, the harmonic/resonance stability of megawatt-scale grid-tied inverters in
weak grids is analysed using impedance modeling, with a particular focus on the
impact of the significantly increased practical converter switching frequencies that
are achievable by SiC MOSFETs compared to Si IGBTs. This analysis is crucial
for understanding the influence of power converter designs—including controllers
and LCL filters—on overall system stability, especially as SiC MOSFETs have
the high potential to significantly reduce switching losses, enabling achievable
switching frequencies of 20 kHz or higher for megawatt-scale power converters
in the future. Passive (hardware-based) and active (controller-based) methods for
enhancing harmonic stability are systematically compared. To aid decision-making,
a comprehensive summary table is presented, assessing various converter designs
and their corresponding stability enhancement methods based on key criteria such
as stability improvement effectiveness, power losses, and component costs. This
serves as a practical guide for selecting optimised trade-offs tailored to the specific
requirements of different applications
Fault current injection from power-electronic converters
Get PDFThe increasing integration of renewable energy into modern power grids has led to a significant rise in the use of power-electronic converters in transmission systems. Unlike traditional synchronous generators, these converters provide precise control over fault current characteristics. Their response during grid faults depends largely on the implemented control strategy and the limitations of the power-semiconductor devices within the converter. This thesis investigates various control strategies and methods for power-electronic converters, analysing their impact on fault current injection, and subsequently evaluating their effects on system protection and system stability, supporting the transition toward a more resilient and sustainable power system
This thesis starts by analysing three prominent current reference calculation methods for Voltage Source Converters (VSCs): positive sequence only current injection as the conventional standard approach; unbalanced current injection to suppress active power oscillations, which reduces the sizing requirement of the DC-bus capacitor; and flexible positive-negative sequence control, enabling balanced regulation of phase voltage and suppression of negative sequence voltage. Analytical comparisons are conducted based on precise grid voltage dip variations and varying active and reactive power set-points, aligned with grid codes and semiconductor current limitations. The methods are validated through simulations, providing insights into their performance in different fault scenarios.
The thesis then further investigates the fault ride-through (FRT) and fast fault current injection (FFCI) capabilities of grid-forming (GFM) converters, which are increasingly favoured for grid stability compared to grid-following (GFL) converters. Existing GFM control strategies under fault conditions are categorized into two approaches: Switched Operation to GFL (SOGFL) mode during faults and Auxiliary Current-Limiting (ACL) control loops. SOGFL provides flexible fault current injection but faces challenges such as increased system complexity and longer recovery times due to mode switching. ACL, while simpler and less sensitive to fault detection inaccuracies, has limited flexibility in addressing diverse grid requirements. Through transient response analysis under both balanced and unbalanced fault scenarios, the advantages and limitations of these methods are thoroughly examined.
To address the fault current injection limitations of existing strategies, this thesis then proposes a novel Fast Fault Current Injection-Virtual Converter System (FFCI-VCS) for GFL converters. This scheme integrates a virtual converter with a virtual impedance network to enable sub-cycle fault current injection and ensure stable operation even under weak grid conditions. By avoiding dependence on phase-locked loop bandwidth adjustments, the FFCI-VCS minimizes stability compromises while achieving rapid fault current response and flexible steady-state tracking of current references. The approach also enhances the efficacy of protection mechanisms such as distance relays. Validation through simulations and experiments demonstrates its effectiveness in reshaping fault current responses and improving FRT and FFCI performance.
Finally, a comprehensive impedance modeling framework is developed to evaluate the stability of VSCs employing FFCI-VCS. Using impedance bode plots, the interactions between converter impedance and grid impedance are analysed, offering clear criteria for system stability under varying short-circuit ratios and control parameters. The analysis demonstrates that while FFCI-VCS enhances fault current injection performance, it also modifies system impedance, necessitating careful tuning of control parameters to maintain stability. The results, validated through both analytical modeling and simulation using the black-box sweep frequency method, offer valuable insights into optimizing the trade-offs between rapid fault response and system stability, ensuring robust performance across a wide range of operating conditions
LLM Geo-Chat Interfaces: Designing A Retrieval Augmented Generation (RAG) Model to Improve Large Language Model (LLM) Geographical Understanding, Answer Spatial Queries and Create Scottish Maps
Get PDFThis research explores how RAG Models can improve the Scottish geographical queries of Large Language Models (LLMs). Specifically, how the main created RAG Model GeoBot, which utilises OpenAI’s LLM GPT-4, effectively incorporates geographical data from the Gazetteer for Scotland, improving OpenAI’s ability to identify local landmarks and Scottish locations. This is supported by GeoBot’s superior Cosine Similarity and ROUGE scores compared to default GPT-4 and the created comparative no code RAG model Botsonic. However, there are still weaknesses with this approach as GeoBot performs poorly in response clarity and readability, indicating that further improvement is needed to create the strongest RAG Model methodology. GeoBot also demonstrates the viability of map generation in a RAG Model, although again some improvement could still be made to this. These results highlight the potential application of GeoBot for geospatial applications.
GeoBot can be accessed through this website: https://www.geos.ed.ac.uk/dev/geobot/main. Password is ‘GIS2025!’. If this does not connect the website is now offline. The full code can be seen in the Technical Report Appendices
Equitable Urban Cycleway Routing using Multi-Criteria Analysis: A Case Study of Inner South London
Get PDFFrequent cycling offers both personal benefits like disease risk reduction and wider city
scale benefits like improved air quality and reduced traffic casualties. While this
emphasises the importance of active-travel modal shift, perceptions of unsafety limits
cycling rates.
Segregated cycleways improve perceived safety, encouraging active travel, with
cycleway placement and orientation being important in influencing cycling rates.
However, demand-orientated routing disproportionately favours demographic groups
already overrepresented among cyclists. To meet Transport for London’s (TFL) goal of
increasing cycling participation across the wider population it is essential that cycleway
alignment considers the needs of underrepresented groups.
This dissertation uses Multi-Criteria Evaluation (MCE) to locate routes which expand
Inner South London’s cycleway network while considering the needs of
underrepresented groups to equitably spread cycleway benefits. The study area is
underserved by both public transport and cycle infrastructure. Network Analysis is used
to find appropriate routes with road segments weighted to consider locational attributes
that reflect inclusivity orientated cycling route choice parameters.
The analysis finds several contiguous North-South routes in densely populated areas of
South London have high suitability. Routes are characterised by their location along
commercial streets with high service density and route connectivity. Analysis also
identifies the value of creating a contiguous network by linking adjacent commercial
corridors using residential often public park adjacent side-streets to create accessible,
secure alignments. When altering impedance weights to favour high street-lighting and
cycle path routing is largely consistent suggesting alignment along commercial streets
is an inclusive practice
Multidimensional Analysis of Fault Slip and River Displacement along the Haiyuan Fault Zone Based on High-Resolution LiDAR DEM
No full textCoseismic displacement magnitudes and event numbers are critical for estimating paleo-earthquake sizes and recurrence intervals. Traditional approaches such as cumulative offset probability distributions (COPD) often suffer from distortion due to rupture complexity and slip variability. This study introduces a machine learning–based workflow that incorporates river channel width as a geomorphic proxy and applies a two-step clustering method combining Bayesian Gaussian Mixture Models and hierarchical clustering. Using 1 m-resolution LiDAR data from a 70 km segment of the Haiyuan Fault, we identified four slip events with average displacements and coefficients of variation (CoV) of 9.92 ± 0.61 m, 3.52 ± 0.71 m, 9.89 ± 1.60 m, and 11.08 ± 2.68 m, respectively. In addition, comparison with one-dimensional offset-only clustering further confirms the effectiveness of incorporating width as a geomorphic time proxy, significantly improving the resolution of paleo-earthquake identification. These results demonstrate the effectiveness of combining geomorphic proxies with data-driven clustering for paleo-earthquake slip reconstruction. This approach offers a promising path forward for improving the resolution of seismic event detection and contributing to more accurate seismic hazard assessments
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