VictorJuiz/thesis huggingface dataset:
Enabling human physiological sensing by leveraging intelligent head-worn wearable systems
Keywords: cyber-physical systems
human physilogical sensing
compressive sensing
wearable computers
embedded machine learning

This thesis explores the challenges of enabling human physiological sensing by leveraging head-worn wearable computer systems. In particular, we want to answer a fundamental question, i.e., could we leverage head-worn wearables to enable accurate and socially-acceptable solutions to improve human healthcare and prevent life-threatening conditions in our daily lives? To that end, we will study the techniques that utilise the unique advantages of wearable computers to (1) facilitate new sensing capabilities to capture various biosignals from the brain, the eyes, facial muscles, sweat glands, and blood vessels, (2) address motion artefacts and environmental noise in real-time with signal processing algorithms and hardware design techniques, and (3) enable long-term, high-fidelity biosignal monitoring with efficient on-chip intelligence and pattern-driven compressive sensing algorithms.
We first demonstrate the ability to capture the activities of the user's brain, eyes, facial muscles, and sweat glands by proposing WAKE, a novel behind-the-ear biosignal sensing wearable. By studying the human anatomy in the ear area, we propose a wearable design to capture brain waves (EEG), eye movements (EOG), facial muscle contractions (EMG), and sweat gland activities (EDA) with a minimal number of sensors. Furthermore, we introduce a Three-fold Cascaded Amplifying (3CA) technique and signal processing algorithms to tame the motion artefacts and environmental noises for capturing high-fidelity signals in real time. We devise a machine-learning model based on the captured signals to detect microsleep with a high temporal resolution.
Second, we will discuss our work on developing an efficient Pattern-dRiven Compressive Sensing framework (PROS) to enable long-term biosignal monitoring on low-power wearables. The system introduces tiny on-chip pattern recognition primitives (TinyPR) and a novel pattern-driven compressive sensing technique (PDCS) that exploits the sparsity of biosignals. They provide the ability to capture high-fidelity biosignals with an ultra-low power footprint. This development will unlock long-term healthcare applications on wearable computers, such as epileptic seizure monitoring, microsleep detection, etc. These applications were previously impractical on energy and resource-constrained wearable computers due to the limited battery lifetime, slow response rate, and inadequate biosignal quality.
Finally, we will further explore the possibility of capturing the activities of a blood vessel (i.e., superficial temporal artery) lying deep inside the user's ear using an ear-worn wearable computer. The captured optical pulse signals (PPG) are used to develop a frequent and comfortable blood pressure monitoring system called eBP. In contrast to existing devices, eBP introduces a novel in-ear wearable system design and algorithms to eliminate the need to block the blood flow inside the ear, alleviating the user's discomfort.
Logic and modality
Keywords: modality
logical necessity
necessity
modal logic
logical truth

In this thesis I consider and argue against various versions of the view that logical truth and necessity are identical. I criticise purely modalist accounts of logical consequence, according to which consequence is just necessary truth-preservation, and I also criticise views on which necessity is identified with some prior understanding of logical truth (as semantic validity, or substitutional validity, or as syntactic derivability). In the process I develop various systems of modal semantics in detail and investigate the logic of logical truth under various alternative hypotheses.
Understanding and mitigating metallic anode degradation in divalent battery systems
Keywords: anode degradation
metallic anode
calcium ion battery
zinc ion battery
aqueous zinc battery
liquid cell TEM

The work in this thesis focuses on the metallic anode in two of the divalent battery systems: aqueous zinc batteries and calcium-ion batteries. By performing systematic studies, we aim to provide a deep understanding of their anode degradation mechanisms:
In Chapter 3, I looked at the ageing-induced degradation in ZnSO4-based aqueous zinc batteries. It was found that ageing can lead to significant anode capacity loss, in some cases over 70% efficiency loss after only 24 hours. We assessed such loss with respect to various factors: ageing time, anode loading, cycling rates etc. and investigated the root causes of such ageing-induced capacity loss using in-situ Computed X-Ray Tomography. A paper based on this chapter, ‘Decoupling and Quantifying Aging-Induced Zn Anode Degradation Processes in Aqueous Zinc Batteries’ has been submitted to Joule and is now under review.
In Chapter 4, I explored a possible strategy to mitigate the dendrite problem in the ZnSO4-based aqueous zinc batteries. By using a single-crystal (002) Zn as an ideal model anode, I promoted planar Zn deposition and defect suppression, which largely resolved the dendrite problem and allowed excellent cell performance at high-rate and long-cycle conditions. A paper based on this chapter, ‘Achieving Ultra‐High Rate Planar and Dendrite‐Free Zinc Electroplating for Aqueous Zinc Battery Anodes’ has been published in Advanced Materials.
In Chapter 5, I systematically studied and visualized the plating and stripping process in the Ca(BH4)2-based calcium-ion battery electrolyte using in-situ TEM. I revealed that despite calcium deposition being mostly globular, calcium dendrite formation can still occur as a result of high current density. In addition, the inhomogeneous CaH2 layer formation can also lead to the formation of localized ‘hot spots’, which can induce unexpected dendrite formation at lower current densities. Two papers based on this chapter, ‘Liquid cell transmission electron microscopy and its applications’ and ‘Current-density-dependent electroplating in Ca electrolytes: From globules to dendrites’, has been published in Royal Society open science and ACS Energy Letters.
Electrochemical studies of the applications of novel carbon-based materials
Keywords: supercapacitor
carbon-based materials
energy storage

In this thesis, the electrochemical behaviour of novel carbon-based materials is investigated in respect of supercapacitor applications. The first chapter explains the concern over climate change, potential for renewable energy, and significance of energy storage. Much emphasis is placed on the mechanism (e.g., electric double-layer capacitance and pseudocapacitance) and electrode materials (e.g., carbon and metal oxides) for supercapacitors. The second chapter introduces the basic principles of electrochemistry as well as electrochemical methods and characterisation techniques used in this work.
In the first project, the electrochemical oxidation of Mn2+ ions to manganese dioxides is carried out on boron-doped diamond electrodes via cyclic voltammetry. A composite electrode is fabricated by potentiostatic deposition of MnO2 on boron doped diamond, and its electrochemical performance is then measured. The motivation of this work is to illustrate that MnO2, a cheap material with pseudocapacitance, can improve the overall performance of carbon-based composite electrodes for supercapacitor applications.
The second work exploits carbonised seaweed paper, which is a biomass-derived carbon material. MnO2 is deposited on seaweed paper-derived carbon potentiostatically to form a composite for electrochemical measurements and characterisation. Seaweed paper after carbonisation benefits from electric double-layer capacitance, whilst incorporation of the pseudocapacitive MnO2 further extends the potential window and specific capacitance of the hybrid electrode materials as supercapacitors.
The third study investigates nickel treated filter paper for supercapacitor applications. Carbon derived from filter paper is produced at low carbonisation temperature with in situ nickel treatment. Its electrochemical behaviour is researched by removing or keeping the nickel particles. Particularly, faradaic battery-type characteristics is observed electrochemically on account of conversion of nickel into electroactive nickel hydroxide in aqueous alkaline media. Nickel treated filter paper acts as a promising supercapacitor material which is economical and environmentally friendly.
The fourth research involves a number of carbon materials derived from biomass and biowaste with bimetallic cobalt/manganese metal-organic frameworks (MOFs) modification. The composite materials take advantage of the electric double-layer capacitance from the biomass-derived carbon and faradaic battery-type contributions from the pyrolysed MOFs in alkaline electrolytes. In particular, the bulk carbon-based electrode material bears favourable comparison with its powdery counterpart in supercapacitor applications.
Overall, this thesis reports the electrochemical studies of novel carbon-based materials for supercapacitor applications in regard to renewable energy and energy storage.
Defining empirical management of acute febrile illness in Myanmar
Keywords: primary care
Myanmar
fever
melioidosis
Burkholderia pseudomallei
antibiotic prescription
antimicrobial resistance

Fever is a common presenting symptom in primary care in low- and middle- income countries (LMICs). Non-malaria pathogens are now responsible in most cases after a decline of malaria in previously malaria endemic regions of Myanmar. It is important to provide appropriate treatment to those patients after malaria is ruled out by rapid tests or microscopy.
The overall aim of this thesis is to improve management of acute non-malaria febrile illness in Myanmar. Empirical treatment strategies with selected antibiotics were devised and their cost-effectiveness was evaluated using a decision tree modelling approach.
A systematic review on infectious neglected tropical diseases (NTDs) was conducted to collate all reports of NTDs in Myanmar (Chapter 2). The review identified diseases (rickettsial infection and leptospirosis) commonly associated with acute fever and this finding partly informed selection of antibiotics for empirical treatment. A cost- effectiveness analysis of empirical treatment showed empirical treatments being cost- saving and C-reactive protein (CRP) guided empirical treatments being highly cost- effective compared to current practice of care in rural Myanmar (Chapter 3). Alongside this, antibiotic use for acute febrile illness was also explored from the prescriber’s perspective by secondary analysis of the data derived from a clinical trial (Chapter 4) and the user’s perspective by public engagement activities (Chapter 6). The secondary data analysis found a substantial variation of antibiotic prescription among primary care doctors for acute febrile illness and the variation remained after accounting for patients’ clinical presentations and CRP test results. Widespread environmental distribution of Burkholderia pseudomallei, the causal organism of melioidosis, which commonly presents as community acquired pneumonia and sepsis, was confirmed by a large nationwide study (Chapter 5).
In conclusion, this thesis uses a multifaceted approach to improve management of acute febrile illness in Myanmar. Findings from this thesis point towards an empirical antibiotic treatment strategy as a potential approach for management of non-malaria febrile illness in rural Myanmar which could be evaluated in field trials.
Investigating infectious diseases using genetic data
Keywords: GWAS
coevolution
infectious disease
virus evolution
human genetics

Infectious diseases have been a major cause of mortality and morbidity throughout human history. The dramatic advances in technology, especially in genome sequencing, have opened a new avenue to study infectious diseases and changed the landscape of public health and medical science. Compared to non-communicable human diseases where human genetics is the sole focus of genetic studies, infectious diseases add another layer of complexity due to the host-pathogen dynamic. Since infection can be seen as the result of the complex interplay of host and pathogen and the environment, a comprehensive understanding requires the incorporation of all these factors.
In this thesis, I explore the different applications of genetic data in studying infectious diseases through the lens of host-pathogen dynamics and their clinical or public health implication. I first used virus whole genome data to rebuild the epidemiological history of Hepatitis C virus subtype 3a (HCV-3a). I showed how World War II had likely led to the spread of HCV-3a from South Asia and becoming a global epidemic. Notably, I also incorporated host genetic data into the analysis and showed how it helped us identify and address the confounding factor of human migration when conducting an evolutionary analysis on HCV-3a. I then integrated previously published methods to investigate protein residue covariation to investigate the signals co-evolution within the Hepatitis B virus (HBV). I built a co-evolution profile for HBV and link them to previous studies to demonstrate how drug resistance is one of the major driving forces of protein residue co-evolution in HBV. Lastly, I explored the potential of integration of national-scale databases that collect pathogen (Second Generation Surveillance System) and host data (UK Biobank) respectively and conducted multiple genome-wide association studies (GWASs) and lay out how such integration can help improve our understanding of human genetic risk factors for infectious diseases. To conclude, I discuss the importance of host-pathogen data integration as well as the need for developing statistical models that can account for both the data volume as well as complexity resulted from such integration.
Projective fibrations in weighted scrolls
Keywords: projective fibrations
rational double points
multi-graded C-algebras
scrolls
degenerations
relative key varieties

This thesis studies classification problems of codimension 1 and codimension 2 threefold families

f : X → P^1 , X ⊂ F_A

fibred in low-degree K3 surfaces over P^1 and embedded in weighted scrolls F_A , where A is an integer matrix defining weights and twists. We classify X such as K3 surfaces with rational double points, Calabi–Yau 3-folds with isolated singularities which extend results of Mullet, K3 surfaces and Calabi–Yau 3-folds with at most Gorenstein singularities. Further, the thesis revisits degeneration of quartic K3 fibred Calabi–Yau threefolds studied some time ago by Gross and Ruan.
The thesis also sets the stage for a general study of fibrations embedded in weighted scrolls

( f : X → B) ,→ (π : F_ A → P^{k−1}[c i ])

over any nonsingular base B ⊂ P^{k−1}[c i ] by proposing a multi-graded C-algebra geometry method for constructing them. We initiate the study of fibrations embedded in families of key varieties such as weighted Grassmannians fibrations, leaving detailed investigations for later work.
Lifetime performance of wind turbines and wind farms
Keywords: wind energy
degradation
lifetime performance
wind turbine
performance decline
blade roughness
wind farm

Wind energy is rapidly expanding as the demand for a low-emissions electricity grid increases. Acknowledging this, and the intermittent nature of the wind resource, both short-term (circa hours) and long-term (circa years) planning must be implemented. To do this accurately, the performance degradation of wind farms must be quantified and accounted for in electricity systems and financial models. This thesis is concerned with quantifying aerodynamic performance decline of wind turbines and wind farms to better understand changes in lifetime performance and more accurately predict wind farm power output.
Wind turbine aerodynamic performance losses are investigated by analysing the effect of roughness on airfoil performance (lift and drag). One of the challenges in quantifying wind turbine performance decline due to roughness is the lack of roughness airfoil data available. A ‘roughness evolution parameter’ is therefore parameterised based on publicly available roughened airfoil experimental tables, which enables roughened airfoil data to be estimated from clean airfoil data. The calculation of the parameter is proposed as a framework, with room for further refinement when more experimental data comes available.
Blade element momentum theory is used to analyse the impact of blade roughness on wind turbine performance. Exemplar wind turbine rotors are designed and the impact of roughness on annual energy production is quantified to be in the range of 2.9–8.6% for realistic levels of roughness. A novel control method is proposed to mitigate losses due to roughness and 0.1–1.0% of annual energy production is recovered.
To account for the long-term variability in wind speed, wind farm performance decline is quantified using long-term corrected capacity factor data from wind farms in the UK, US and Australia – 0.26, 0.72 and 0.43 capacity factor percentage points per year respectively. To do so, power output data is combined with reanalysis wind speed data to correct for variability and biases in the data, allowing the underlying performance trend to be realised. To address shortcomings in the data (e.g. undetected downtime or reanalysis errors) a novel long-term correction approach is used which reduces variability in the results.
Reanalysis wind speed data and wind farm datasets are utilised for a supervised machine learning performance prediction model. Due to the inclusion of additional metadata, this model is able to predict wind farm capacity factor output with a 56–90% improvement in mean absolute error value when compared to predicting power output using a wind farm power curve.
Continuous touchscreen biometrics: authentication and privacy concerns
Keywords: authentication
privacy
mobile authentication
secuirty
biometrics
touchscreen biometrics

In the age of instant communication, smartphones have become an integral part of our daily lives, with a significant portion of the population using them for a variety of tasks such as messaging, banking, and even recording sensitive health information. However, the increasing reliance on smartphones has also made them a prime target for cybercriminals, who can use various tactics to gain access to our sensitive data. In light of this, it is crucial that individuals and organisations prioritise the security of their smartphones to protect against the abundance of threats around us. While there are dozens of methods to verify the identity of users before granting them access to a device, many of them lack effectiveness in terms of usability and potential vulnerabilities.
In this thesis, we aim to advance the field of touchscreen biometrics which promises to alleviate some of the recurring issues. This area of research deals with the use of touch interactions, such as gestures and finger movements, as a means of identifying or authenticating individuals. First, we provide a detailed explanation of the common procedure for evaluating touch-based authentication systems and examine the potential pitfalls and concerns that can arise during this process. The impact of the pitfalls is evaluated and quantified on a newly collected large-scale dataset. We also discuss the prevalence of these issues in the related literature and provide recommendations for best practices when developing continuous touch-based authentication systems. Then we provide a comprehensive overview of the techniques that are commonly used for modelling touch-based authentication, including the various features, classifiers, and aggregation methods that are employed in this field. We compare the approaches under controlled, fair conditions in order to determine the top-performing techniques. Based on our findings, we introduce methods that outperform the current state-of-the-art.
Finally, as a conclusion to our advancements in the development of touchscreen authentication technology, we explore any negative effects our work may cause to an ordinary user of mobile websites and applications. In particular, we look into any threats that can affect the privacy of the user, such as tracking them and revealing their personal information based on their behaviour on smartphones.
The performed Dao: understanding the Zhuangzi with the literary form approach
Keywords: Zhuangzi
textual performance
irony
paradox
literary form
Daoism
narrative

This thesis adopts the literary form approach to the analysis of the Zhuangzi. I argue that the literary forms deployed in the Zhuangzi are not neutral and empty but philosophically meaningful. The leading question dealt in the thesis is how form and content are connected in the Zhuangzi. On the macro level, I provide a characterisation for the methodology to which I refer as the relaxed literary form approach. It is a modified version of the past literary form approach. On the micro level, I study the forms—including narrative, irony, and paradox—in detail, showing how these forms contribute to the meaning construction of the Zhuangzi. I argue that the form of narrative is to construct the “constellation of perspectives”; the form of irony is to bring about the experience of uncertainty and not-knowing; the form of paradox is to put the text in an ever-drifting dynamic. This investigation leads to a fundamental reconceptualisation of the Zhuangzi and the dao: instead of being represented the dao is performed in the text, and thus the Zhuangzi is a dao-performance.