VictorJuiz/thesis huggingface dataset:
Signal processing methods for heart rate variability

Heart rate variability (HRV), the changes in the beat-to-beat heart rate calculated from the electrocardiogram (ECG), is a key indicator of an individual's cardiovascular condition. Assessment of HRV has been shown to aid clinical diagnosis and intervention strategies. However, the variety of HRV estimation methods and contradictory reports in this field indicate that there is a need for a more rigorous investigation of these methods as aids to clinical evaluation. This thesis investigates the development of appropriate HRV signal processing techniques in the context of pilot studies in two fields of potential application, sleep and head-up tilting (HUT).
A novel method for characterising normality in the ECG using both timing information and morphological characteristics is presented. A neural network, used to learn the beat-to-beat variations in ECG waveform morphology, is shown to provide a highly sensitive technique for identifying normal beats.
Fast Fourier Transform (FFT) based frequency-domain HRV techniques, which require re-sampling of the inherently unevenly sampled heart beat time-series (RR tachogram) to produce an evenly sampled time series, are then explored using a new method for producing an artificial RR tachogram. Re-sampling is shown to produce a significant error in the estimation of an (entirely specified) artificial RR tachogram. The Lomb periodogram, a method which requires no re-sampling and is applicable to the unevenly sampled nature of the signal is investigated. Experiments demonstrate that the Lomb periodogram is superior to the FFT for evaluating HRV measured by the LF/HF-ratio, a ratio of the low to high frequency power in the RR tachogram within a specified band (0.04-0.4 Hz). The effect of adding artificial ectopic beats in the RR tachogram is then considered and it is shown that ectopic beats significantly alter the spectrum and therefore must be removed or replaced. Replacing ectopic beats by phantom beats is compared to the case of ectopic-realted RR interval removal for the FFT and Lomb methods for varying levels of ectopy. The Lomb periodogram is shown to provide a signficantly better estimate of the LF/HF- ratio under these conditions and is a robust method for measuring the LF/HF-ratio in the presence of (a possibly unknown number of) ectpoic beats or artefacts.
The Lomb peridogram and FFT-based techniques are applied to a database of sleep apnoeic and normal subjects. A new method of assessing HRV during sleep is proposed to minimise the confounding effects on HRV of changes due to changing mental activity. Estimation of LF/HF-ratio using the Lomb technique is shown to separate these two patient groups more effectively than with FFT-based techniques. Results are also presented for the application of these methods to controlled (HUT) studies on subjects with syncope, an autonomic nervous system problem, which indicate that the techniques developed in this thesis may provide a method for differentiating between sub-classes of syncope.

Keywords: signal processing
Fast Fourier Transform
heart rate variability
Lomb periodogram
Advisor: Tarassenko, L
Algebras for tree algorithms

This thesis presents an investigation into the properties of various algebras of trees. In particular, we study the influence that the structure of a tree algebra has on the solution of algorithmic problems about trees in that algebra. The investigation is conducted within the framework provided by the Bird-Meertens formalism, a calculus for the construction of programs by equational reasoning from their specifications.
We present three different tree algebras: two kinds of binary tree and a kind of general tree. One of the binary tree algebras, called "hip trees", is new. Instead of being built with a single ternary operator, hip trees are built with two binary operators which respectively add left and right children to trees which do not already have them; these operators enjoy a kind of associativity property.
Each of these algebras brings with it with a class of "structure-respecting" functions called catamorphisms; the definition of a catamorphism and a number of its properties come for free from the definition of the algebra, because the algebra is chosen to be initial in a class of algebras induced by a (cocontinuous) functor. Each algebra also brings with it, but not for free, classes of "structure-preserving" functions called accumulations. An accumulation is a function that preserves the shape of a structured object such as a tree, but replaces each element of that object with some catamorphism applied to some of the other elements. The two classes of accumulation that we study are the "upwards" and "downwards" accumulations, which pass information from the leaves of a tree towards the root and from the root towards the leaves, respectively.
Upwards and downwards accumulations turn out to be the key to the solution of many problems about trees. We derive accumulation-based algorithms for a number of problems; these include the parallel prefix algorithm for the prefix sums problem, algorithms for bracket matching and for drawing binary and general trees, and evaluators for decorating parse trees according to an attribute grammar.

Keywords: tree algebras
Advisor: Bird, R
Ultrasound-triggered drug release from liposomes using nanoscale cavitation nuclei

Side effects of current chemotherapeutics limit their use in cancer therapy. Although many current drugs are highly toxic and potent, the effects they have on non-cancerous tissue are unbearable for patients. Targeting these drugs may provide a means to restrict their toxic effects to only cancer tissue while leaving healthy tissue unaffected. This approach requires that the drug is only available in cancer tissue, which has been achieved here by encapsulating drugs into liposomal nano-capsules which are capable of passively accumulating in cancerous tissue via the enhanced permeability and retention effect (EPR). In addition to localisation, a threshold dose must be achieved to deliver the desired toxic effect to the target tumour tissue. Previous strategies have relied on passive 'leaching' of the drug from liposomes, however this 'leaching' does not necessarily achieve the threshold dose required. In the present work, a new generation of liposomes has been developed whereby release is solely achieved in the presence of ultrasound triggered cavitation.
Instigation of such cavitation events would normally require the target tissue be exposed to high and possibly damaging ultrasound pressures. To remove the need for these high pressures, cavitation nuclei have been developed to lower the cavitation threshold of surrounding media. To allow for improved co-localisation and treatment deeper into cancer tissue, cavitation nuclei were developed to be in the nanoscale size range. Two types of novel cavitation nuclei were produced, a rough surfaced carbon nanoparticle (CNP, ~180 nm) and smooth shaped polymeric nano-cup particle (NC, ~150, 470, or 770 nm). Both types of particle are solid nanoparticles with gas entrapped on their surface which was capable of cavitating in response to ultrasound without greatly affecting the particle itself. These particles are classified as cavicatalytic nanoparticles due to their ability to reduce the cavitation threshold of their surrounding media without being destroyed themselves. Finally, an entirely nanoscale release system was developed and tested in vitro and in vivo. The drug carrier (the liposome) and effector agent (the cavicatalytic nanoparticle) were used to demonstrate ultrasound triggered drug release, specifically in response to the generation of cavitation events. These cavitation events could be non-invasively monitored and characterised, adding to the potential clinical utility of the technologies developed and described here.

Keywords: HIFU
Nanotechnology
Chemotherapeutic
Ultrasound
Cancer
Liposomes
Nanoparticles
Advisor: Coussios, C
Carlisle, R
Solid acid zeolite catalysts for benzene/ ethylene alkylation reactions

Alkylation of benzene with ethylene to ethylbenzene is widely used in the petrochemical industry. Ethylbenzene is an important raw material in the petrochemical industry. It is used as feedstock for the production of styrene, an important material for plastic and rubber production.
The conventional catalyst for this alkylation process is AlCl₃, which accounted for 24% of the worldwide ethylbenzene production in 2009.
As utilization of this catalyst involves problems with separation, handling, safety and corrosion, immense efforts have been devoted to the development of new catalysts for ethylbenzene production.
Compared with AlCl₃, zeolites possess advantages in easy separation, low corrosion, high surface area as well as uniform microporous structure coupled to shape selectivity, and thus they are better acidic catalysts when applied in petrochemical industry.
In this thesis, zeolite catalysts based on Y, ZSM-5 and HBeta were prepared and characterized by several techniques (XRD, MAS NMR, BET and SEM). The catalytic performance of these zeolite catalysts has been studied in the benzene/ethylene alkylation reaction in the gas phase using a fixed bed reactor at reaction temperature of 250ºC and a 5 bar pressure with a 0.5 h-1 ethylene space velocity (WHSV) and different benzene to ethylene feed ratios. The products were identified by GC/MS and quantified by gas chromatography.
These studies highlight the importance of ion-exchange with rare earth cations as a powerful method to control the local structural and catalytic properties of zeolites, and also to enhance the acid properties upon rare earth exchange.
Most notable is the significant enhancement in product selectivity – viz. ethylbenzene selectivity- for La and Ce ion-exchanged HZSM-5 zeolite catalysts, showing a 30% + increase in selectivity for the alkylation reaction after rare-earth ion exchange.
This work done at KACST-Oxford Petrochemical Research Center (KOPRC) in the Inorganic Chemistry Laboratory, Oxford University.

Keywords: ethylbenzene
alkylation
zeolite
Advisor: Edwards, P
Four Middle English Charlemagne romances: a revaluation of the non-cyclic verse texts and the holograph Sir Ferumbras

Four Middle English Charlemagne Romances are examined with the intention of disproving conventional claims that English romances of the 'Matter of France' are typically undistinguished.
The manuscript of the Ashmole Sir Ferumbras is a holograph; preserved with it, on sheets which originally formed the binding, is a portion of the poem's rough draft. Comparison of the draft with the fair copy reveals something of the romancer's translational and compositional method, and illustrates well his enthusiasm for, and ability occasionally to improve upon, his French source.
The fragment of The Song of Roland displays some sensitivity to the heroic essence of its famous French model. The poem also displays, however, a free, sensitive, sometimes eloquent and technically complex, adaptation of notable features of that model.
The Sege of Melayne has been recognized for its energy; but extensive studies of the poem appear to have been prevented by an inability to account for the poem's lack of known sources and its use of extraordinary episodes and unusual narrative techniques. Analogues and possible influences do, however, exist; and most reveal the poem's remarkable affinity with propagandistic crusading literature. This affinity goes some way toward explaining, and allowing us to appreciate, the poem's unusual features.
Rauf Coilyear is unusually described as a competent and straightforwardly humorous tale similar in spirit to its analogues. A closer look, however, shows the humour to be complicated by the seriousness of a social critique; at times the hero's experiences is far from laughable. There is, in fact, some similarity, both of incident and theme, with the best poems of the 'Gawain-group'. That a comparison with such poems (and, indeed, with 'serious' elements in the other Charlemagne romances) can convincingly be made suggests that our expectations of the poem's literary significance should be revised accordingly.

Keywords: The Sege of Melayne
English Charlemagne romances
Song of Roland
The Taill of Rauf Coilyear
Sir Firumbras
Middle English
poems
Advisor: Gray, D
Behaviour of footings for offshore structures under combined loads

The lack of knowledge about the behaviour of footings for jack-up rigs under storm loads poses a design problem which can be tackled by model testing. The areas of prime concern are the ultimate loads on footings under combined loading, which affects the safety of the rig, and the rotational stiffness, which affects the interaction between the foundation and the structure. A programme of loading tests was performed on model footings on clay, and was divided into two stages: monotonic loading and cyclic loading. The clay samples were obtained by consolidating Speswhite kaolin slurry in cylindrical tanks 450mm in diameter. The strength and compressibility characteristics of the samples were verified by means of standard laboratory tests. The model footings were 50mm and 100mm in diameter and several shapes were tested: circular flat plate, cones of various angles and model spud-cans. Loads and displacements were monitored using appropriate instrumentation and a data logger. A series of central vertical loading tests provided data for comparison with existing bearing capacity theories. Combined loading tests were performed applying a displacement controlled horizontal load at a fixed height above the footing which was also subjected to a fixed vertical load. The main series of tests involved a parametric study of the relevant variables. Special tests allowed the assessment of the effect of embedment of the footing and the interaction of a flexible leg with the foundation. Cyclic loading tests were carried out using a load controlled system which applied a sinusoidal load simulating wave action. Effects of currents were investigated by introducing an offset to the loading cycle. The influence of amplitude and period of loading as well as the influence of vertical load were also investigated. Special tests were carried out to cover some peculiarities of real loading conditions. Fitting of a three-parameter hyperbola to the test results provided a systematic and accurate method of analysis of monotonic loading tests, leading to valuable information involving stiffness and ultimate loads. Analysis of cyclic loading tests yielded useful qualitative information regarding the progress of settlement and the variation of rotational stiffness and damping ratio with the number of cycles.

Keywords: offshore
foundation
clay
jack-up
Advisor: Houlsby, G
Fragments of Piscataway: a preliminary description

The goal of the present project is to provide a preliminary descriptive analysis of the language found in a short manuscript in the Special Collections of the Georgetown University Library. The manuscript is a five-page Catholic catechism written in an Eastern Algonquian language. It is the only extant record of the language which is presumed to be Piscataway (also called Conoy). The identification of the language is based on the attribution of authorship to Father Andrew White, a seventeenth-century English Jesuit missionary. By providing as much of a description as possible through morphological and phonological analysis of the data, I hope to recover some knowledge about this extinct language and add to the sparse data on Eastern Algonquian languages. Because the goal of the project is to uncover the data in the manuscript, no theoretical viewpoint has been adopted regarding morphological entities or processes.

Keywords: Comparative Philology
General Linguistics
Phonetics
Advisor: Cameron, D
Long-distance trade and the exploitation of arid landscapes in the Roman imperial period (1st – 3rd centuries AD)

If as argued the Mediterranean consisted in Antiquity of a unity determined by similar environmental factors and crises which were mitigated through established networks of trade and exchange, the border regions of the Roman Mediterranean, particularly to the South and East, were characterised by a radically different environment. This thesis focuses on the development of three of the arid regions bordering the ancient Mediterranean, namely the Fazzan oases in the Libyan Sahara, the Eastern Desert of Egypt and the region of Palmyra in Syria. These arid regions have received considerable archaeological attention in recent years, and a review of them will highlight the factors which enabled these regions to interact with the Roman Empire through trading dynamics, but also through the development of local resources. Central questions within this thesis concern the extent to which the environment would have tailored the potential of these regions, and if the existence of trade routes and social networks both affected and were affected by settlement and exploitation patterns in the region. Trade was created by geographically much broader social requirements for foreign or exotic goods, yet was restricted by the possibility to pass through these regions. Developments were conditioned by the constant need for balance between the state as a power enforcing and representing peace and security and local entities, and what the local social organisation had to offer in term of rent and stability to the state as an institution.
After an introduction (Chapter 1) delineating the aims of the thesis, Chapter 2 defines influential theories and models that will be considered for this thesis, namely environmental factors, social networks and institutional economics. The archaeological evidence is then discussed in each relevant chapter: Chapter 3: The Libyan Sahara; Chapter 4: The Eastern Desert of Egypt; Chapter 5: Palmyra.
Chapter 6 discusses major factors that may work as explanations for the development of agriculture, the exploitation mineral resources, and trade in these regions. The choice of regions both inside and outside the Roman Empire also allows a discussion on the rise of economic activities linked to the imperial economy. As such, the thesis moves away from a romano-centric perspective and proposes to look instead for internal factors, such as the development of complex societies with organisational frameworks and social networks which enable them to overcome the challenges of their geo-climatic settings.
This study concludes that the developments identified in each chapter were not a factor of environmental changes but human agency. The state, or private individuals or communities successfully organised the resources necessary to integrate the regions into wider networks of intense trade in the imperial period. These concerned both physical infrastructure, and the development of far-reaching social networks.

Keywords: Roman Archaeology
Egypt
Libya
Syria
Advisor: Robinson, D
Development and application of asymmetric C-N bond formation

A synthetic investigation on the chemistry of cyclotryptamine derived natural products, with a particular focus on the synthesis of the trimeric-alkaloid, hodgkinsine. Methodology has been developed to tackle this complex natural product which utilises a desymmetrization approach; this strategy hinges on the development and applications of asymmetric C-N bond forming reactions.
Chapter one examines elements of symmetry in natural products, looking in particular at the synthesis of compounds which contain cyclotryptamine functionality. Chapter two contains a brief review of enantioselective desymmetrization paying attention, if possible, on its application in the synthesis of natural products. In the remaining chapters we discuss our own progress and results in our pursuit of an efficient enantioselective total synthesis of hodgkinsine.

Keywords: hodgkinsine
total synthesis
desymmetrization
Advisor: Willis, M
Cross-lingual interation online: blogging the 2010 Haitian earthquake

This research analyzes linguistic barriers and cross-lingual interaction in the blogosphere. The Internet is often thought to democratize access to information; however linguistic barriers remain prevalent. This study seeks to determine the extent to which information about recent world events flows between languages within the blogosphere using blogs discussing the 2010 Haitian earthquake in English, Spanish, and Japanese as a case study.
This study represents a new approach to Internet-language research. Previous studies of language online have either sought to determine the number of pages in different languages or have been relatively small and qualitatively focused. This research, in contrast, constructs a dataset of over 100,000 blogs, examines this set with hyperlink analysis, and qualitatively codes the cross-lingual links. The relationship between two blogs sharing a cross-lingual hyperlink as well as the type of author writing each blog is coded.
Results from this analysis show that in this dataset: 1) English-language blogs are significantly less likely to link cross-lingually than either Spanish or Japanese blogs; 2) Awareness of foreign language content increases among bloggers over time; 3) Most cross-lingual links are created on personal blogs and link to (primarily English-language) media; 4) Most cross-lingual links signal a citation or reference relationship, while a smaller, although not insignificant, number of cross-lingual links signal a translation of blog content.
While the dataset does not show the naive ideal of global discourse, the dataset does reveal a surprising level of human translation in the blogosphere. Such human translation has a superior potential to machine translation in that it can translate cultural meaning in addition to linguistic meaning. Ultimately, some combination of machine translation, human translation, and social encouragement through sites like Global Voices might best increase cross-lingual communication online.

Keywords: Social Network Analysis
Language
Sociolinguistics
Knowledge
Advisor: Meyer, E
Default Forecasting in KMV

In this dissertation, we present the basic ideals and structrues of the KMV in the framework of both Merton and Vasicek and Kealhofer Models, and also explain some conditions before implementing these two models. Moreover, we extend the Merton's model to a special case in KMV. We use the real data to examine the default probability of the several rms which have different financial conditions in three industries, and find out some implications among the parameters we input and derive.