VictorJuiz/thesis huggingface dataset:
On the role of explainability and uncertainty in ensuring safety of AI applications

Deep learning, and in particular neural networks (NNs), have seen a surge in popularity over the past decade. Their use has increased in, often safety-critical, decision-making systems such as self-driving, medical diagnosis and natural language processing. Thus, there is an urgent need for methodologies to aid the development of AI-based systems. In this thesis, we investigate the role that explainability and uncertainty can play in providing safety assurance for AI applications based on neural networks. Our first contribution, studied primarily for decisions based on neural network models, is a method to derive local explanations with provable robustness and optimality guarantees called Optimal Robust Explanations (OREs). OREs imply the model prediction and thus provide sufficient reason for the model decision. We develop an algorithm to extract OREs that uses a neural network verification tool Marabou or Neurify as a black-box solver. We demonstrate the usefulness of OREs in model development and safety assurance tasks such as model debugging, bias evaluation and repair of explanations provided by non-formal explainers such as Anchors. Our second contribution focuses on an autonomous driving scenario enabled by an end-to-end Bayesian neural network (BNN) controller trained on data from the Carla simulator. BNNs have the ability to capture the uncertainty within the learning model, while retaining the main advantages intrinsic to neural networks. We propose two methods to evaluate the safety of decisions of BNN controllers in the presence of uncertainty in offline and online settings. We develop techniques to approximate bounds on the safety of the entire system with respect to given criteria, with high probability and a priori statistical guarantees. Our final contribution a collection of methods that combine the uncertainty information available from Bayesian neural networks with local explanation methods. We show how to formulate Bayesian versions of existing feature scoring explanation methods, as well as a Bayesian version of our OREs, called Bayes-optimal robust explanations (B-OREs). We define a covering explanation, which condenses the information produced from a number of BNN posterior samples into a single explanation, with a probability of the likelihood that this explanation is an explanation of a random sample. In the case of Bayes-optimal robust covering explanations, we obtain a probability for how likely the explanation is to imply the prediction. We combine Bayesian covering explanations with a notion of feature uncertainty, to give an ordering of importance to each feature that appears in the covering explanation, and we show that feature uncertainty can be used to provide a global overview of the input features that the model most associates with each class.

Keywords: verification
neural networks
AI safety
explainability
Advisor: Kwiatkowska, M
Experimental validation of intergranular stress corrosion cracking predictive models

Intergranular Stress Corrosion Cracking (IGSCC) has been one of the most important challenges to nuclear power plant operation worldwide. The degradation of alloy 600 (Ni-based alloy) and its susceptibility to Stress Corrosion Cracking (SCC) when exposed to primary water environment in pressurized water reactors (PWRs) has been a topic of interest for many decades among the SCC community. However, the understanding or prediction of SCC mechanisms remains questionable. To address this, an IGSCC predictive model called ‘Local Model’ has been developed in the framework of EDF’s CSI project. The main focus of this research is to investigate IGSCC in alloy 600 and to experimentally validate a predictive model. Firstly, it is important to know whether stress corrosion cracking occurs in these materials, in the way presented in the existing experiments and models in the literature. These have shown a very large scattering for the needed for the crack initiation and crack propagation, indicating significant model uncertainties.
In this thesis, an experimental and modelling program has been developed for investigating SCC in alloy 600 for conditions simulating PWR conditions under constant load. The goal of the experiments was to find a reliable and quantitative determination of crack initiation and crack propagation for these conditions. For the modelling aspect, the aim was to determine the critical parameters of SCC by considering the phenomena in the local scale of grain boundaries and crack tips. The model requirements include the ability to predict the crack initiation and to model crack growth rate as a function of macroscopic and measurable parameters. This has been validated by experiment to ensure that the assumptions of the model are realistic enough to make sure of reliability for reactor safety applications. By doing this, the model allows for a better understanding of the underlying mechanisms of SCC. As such, it focuses on the phenomenological approach rather than the empirical approaches in other models.

Keywords: Stress Corrosion Cracking (SCC)
Transmission Kikuchi Diffraction
3D-Electron Back Scattered Diffraction (3D-EBSD)
Local Model
Alloy 600
Advisor: Lozano-Perez, S
Rheology of colloidal clay gels and their mixtures

We studied the use of Laponite EP, an organically surface coated laponite, as an alternative of xanthan in product formulation. Its combination with bentonite in agrochemical formulation showed similar rheological behaviour as the commonly used xanthan - bentonite combination. Laponite EP and bentonite display some synergism: analogous rheological properties could not be achieved using each clay alone or using a non-coated laponite RD - bentonite blend. The microstructure suggested two networks cooperating. The results highlighted the effect of the coating on the rheology of the clay and the product. Although the surface coating did not impact the surface charge of the clay, it may have prevented the adsorption of other components on its surface. The rheological behaviour of the gel Laponite EP - bentonite under diverse conditions was modelled using a mixture design approach. We varied the amount of salt (MgCl2) and surfactant (Tween 20) in the solution as well as the pH (from 4 to 9). We focused on modelling the storage modulus G′, the loss modulus G′′ and the critical stress σc. The models obtained underlined some complex interactions with antagonistic effects between the components.
The ageing of attapulgite, bentonite gels and their mixture was examined using rheology (oscillatory and creep tests) and microscopy (HPF Cryo-SEM and X-Ray tomography). The rheological results showed that the gels became stronger and more viscous with time. For bentonite, this could be explained by the rearrangement of the platelets over time and an increase in their connections. Regarding attapulgite, the strengthening of the gel was delayed compared to the other gels due to a change in the long range structure of the network getting more large pores. The rheological trend followed by the clay blend is similar to the one found for bentonite which determines its rheology. However, the evolution of the microstructure formed by the platelets in the mixture differs. The pore size distribution of the blend was analogous to the one found for attapulgite. Microscopic images suggested the formation of two networks interacting. Akin to bentonite, the long range structure of the gel did not show any drastic change with time. Therefore, the time effect on the rheology of the composite may have been due to stronger interactions between the needles and the platelets at a short range.

Keywords: Microscopy
Ageing
Rheology
Clay
Mixture Design
Gel
Advisor: Formstone, C
Aarts, D
Characteristics and analysis of an Open-loop Ground Source Heating System

Open-loop ground source heating systems (GSHS) provide cooling and heating to a space with several positive sustainable and economical factors over fossil-fuel-based alternatives. The worldwide number of GSHS is increasing but they remain relatively rare compared to alternatives. Therefore the overall GSHS industry might still be considered young in its GSHS-specific experience of testing, design and modelling practises. Characterisation and analysis of an operational system, in light of past design assumptions, modelling and testing practices, remains a novel opportunity to provide key insights and learnings. Several studies have been conducted into the testing and operational performance of an open-loop GSHS. Historical operational data showed thermal fluctuations at an abstraction well in advance of predicted thermal breakthrough times. An explanation of these occurrences was sought by evaluating prior testing and modelling assumptions. Models were constructed to evaluate pump and tracer testing data, calibrating hydraulic and solute-transport properties of the host aquifer. Calibration of the thermal transport properties, not previously conducted, was pursued through isolating an early thermal event and several years of operational data. Work identified differing hydraulic and transport properties to those previously assumed in design. The significance and sensitivity of free parameters in each model variant was evaluated. Re-calibrated properties yielded inconclusive results; attributing thermal fluctuations to either regional groundwater temperature fluctuations (reinforcing earlier predictions that thermal breakthrough was not yet expected) and/or earlier than expected thermal breakthrough. Calibration efforts highlighted the importance of comprehensive testing and instrumentation to support design and modelling efforts --- namely, careful consideration and increased density of sensor placement, along with geophysical investigation of down-hole well properties. Modelling of open-loop GSHS operational strategies (unidirectional and seasonally reversed) was conducted to provide quantitative support to the naive intuitive benefits of the latter. A seasonally reversed strategy was found to outperform unidirectional modes considering varying injection temperature, peak energy loads and seasonal imbalances in operation. Furthermore, the superior performance in both energy efficiency and predicted design life was observed without permitting the system to be responsive to detected thermal stores. A responsive seasonally reversed system is expected to further outperform its unidirectional counterpart.

Keywords: seasonally reversed
well tests / pump tests
ground source heating system
unidirectional
open-loop
well doublet
thermal tracer test
geothermal
tracer test
transport in porous media
Advisor: MacMinn, C
Victims and survivors of rape in late medieval France and Burgundy


This thesis examines victim/survivor experiences of rape and other sexual violations in late medieval France and Burgundy. Though scholars have studied rape in medieval France, few have considered what it was like for the women who endured rape, and none have explored how victims/survivors thought about their own consent. This thesis addresses that gap in the scholarship, proposes new methods for how we might examine victim/survivor experience in medieval documents, and argues that the only ethical study of rape is one that foregrounds such experiences. When rape was violent, women often resisted violently, and understood their ability to consent as something worth physically defending. The discourse of consent had great rhetorical power, and it was used to justify the victim’s/survivor’s violent actions in the face of rape, reinscribing them with personhood. But other, non-violent sex acts could also be harmful, such as marital promises used to coerce women into sex. Women in medieval France understood that their husbands might perpetrate sexual abuse against them, and that these acts were violative, even if they were not termed rapes. Victim/survivor experience was shaped by the community they lived in, and how others responded to the rape. Dijon was a community with a culture of rape and a culture of resistance. Its rape culture was characterized by physical violence, gang rapes, and the victimization of marginalized and/or vulnerable women. The culture of resistance was characterized by the anger and fear that victims/survivors felt and the defence they mounted against the rapists, but also by the community support they received in the form of testimony and direct intervention. Sex workers were extremely vulnerable to rape due to the nature of their employment, their social status, and the manner in which men tended to treat them. But despite this vulnerability they too had community ties and access to the courts.

Keywords: middle ages
medieval france
medieval women
medieval gender
medieval consent
sexual assault
rape
medieval rape
medieval
sexual violence
consent
Advisor: Skoda, H
Forrest, I
Blow-ups in non-reductive GIT and moduli spaces of unstable vector bundles over curves

We use non-reductive geometric invariant theory (NRGIT) to study a moduli problem involving pure sheaves of fixed Harder-Narasimhan type. The construction of moduli spaces for such sheaves can be reduced to the construction of NRGIT quotients of subschemes of Quot schemes. Hitherto NRGIT has been developed only for actions on varieties, whereas Quot schemes are not varieties.
So first we put the NRGIT developed by Bérczi et al ([Bér+18b], [Bér+16]) into a scheme-theoretic framework. Linear actions of ˆU := U ⋊λ Gm are considered, where U is a unipotent group graded by λ : Gm → Aut(U ). The condition “semistability coincides with stability” (or “ss=s”) required by Bérczi et al is enhanced scheme-theoretically for an ample ˆU -linearisation on a projective scheme X. With “ss=s”, we show that an open subscheme of X has a geometric quotient X// ˆU , which is not necessarily reduced. When “ss=s” fails but a weaker condition holds, a blow-up of X satisfies “ss=s”. For reduced X, our results are close to those of Bérczi et al, except we need only one blow-up.
Next we apply our NRGIT to the moduli problem. Besides the Harder- Narasimhan type τ , we fix the vector δ representing dimensions of spaces of unipotent endomorphisms. We extend the notion of (τ, δ)-stable sheaves considered by Hoskins and Jackson ([Jac21], [HJ21]) to (τ, δ)-stable families, and define a moduli functor M′τ,δ classifying (τ, δ)-families. A coarse moduli space for M′τ,δ can be constructed as a NRGIT quotient. Hoskins and Jackson considered the reduced version of this NRGIT problem. Now we study it scheme-theoretically. When τ has length 2, we can perform the blow-up and apply our NRGIT. For general lengths, we need additional hypotheses on τ to satisfy the condition for blow-ups.

Keywords: nonreductive geometric invariant theory
moduli of sheaves of length 2
Advisor: Kirwan, F
Financing the fight: The economics of French resistance during World War II

The financing of French resistance is one of the least studied aspects pertaining to France’s complex role in the Second World War. By understanding how, and by whom, French resistance forces were funded, both within and without France’s metropolitan borders, a fundamental reappraisal of the existing historiography of French resistance becomes possible.
This work argues that, without concerted efforts by the British and U.S. governments and the Free French, this financing would not have been possible and, due to a lack of funds, nascent resistance activity would have been monetarily hampered, if not extinguished entirely. However, the development of these funding lines was convoluted and rendered difficult due to the transportation of agents and funds behind enemy lines. They were heavily impacted by political machinations and operational security protocols but, through the efforts of financial administrators, including intermediaries from the Bank of England, resistance activity in France was successfully supported by external funding from 1941. It has been established that many who participated in fundraising were not French nationals and money was transferred across the planet which eventually arrived in France through clandestine landings and airdrops.
The thesis takes a transnational approach. By using digital humanities techniques, including social network analysis (S.N.A.) and geographic information systems (G.I.S.), alongside forensic accountancy of the Free French and Special Operations Executive (S.O.E.) accounts, the thesis seeks to ‘follow the money’ across the planet, from donor to end-recipient. Those receiving the funds included Maquis forces and British- and French-run networks in France.
Having made use of a range of primary and secondary sources from France, Britain, the U.S.A. and Australia, this work builds upon the very limited existing historiography. Its primary sources include a 2017 interview with the late Daniel Cordier, the wartime secretary of Jean Moulin.

Keywords: Social Network Analysis (SNA)
Military History
Geographic Information Systems (GIS)
French Resistance
Modern European History
Military Logistics
French History
Economic History
Second World War
Digital Humanities
World War 2
Advisor: Gildea, R
Algebraic solutions to the dynamics of dissipative many-body quantum systems

From the motion of hurricanes to the cooling of a cup of tea, dissipative dynamics are ubiquitous in nature. Unfortunately, when studying lattice-based strongly correlated quantum systems, a common focus of experiments and highly relevant for material science, the curse of dimensionality prevents us from directly solving the exact equations describing the dissipative motion. We instead often use approximations and numerical analysis, as few analytical techniques currently exist which can provide useful insights.
This thesis studies the constraints that non-abelian algebraic structures place on the dynamics of such non-equilibrium many-body quantum systems. In doing so, we develop novel algebraic methods that provide previously absent analytic insight into a range of problems. We apply these new techniques to study dynamical phases of quantum matter that are of both theoretical and experimental interest.
We study how simple algebraic structures imply persistent non-stationarity in dissipative many-body quantum systems. These results enable us to develop a theory of quantum synchronisation based on symmetries and to explore a novel class of time crystals where order is induced by noise. These dynamical phases of matter have been gaining recent interest for their insights into thermalisation and their potential application in quantum technologies. We therefore use our results to explore experimentally realisable models.
We also use the general principles of prethermalisation to propose a new theory to potentially explain recent experiments studying light-induced superconductivity in terms of eta-pairing and approximate symmetries. We discuss the merits and weaknesses of our proposal in relation to the experimental evidence. We also indicate techniques that, within our theory, stabilise superconducting states by harnessing the quantum Zeno effect
For certain systems, known as integrable, there are enough symmetries to allow for exact solutions using the Bethe ansatz. We demonstrate that Bethe ansatz techniques can be extended and applied to non-equilibrium problems. As an example, we use this method to analytically study the dynamical phase transitions of an XXZ spin chain with boundary loss.

Keywords: Quantum
dissipation
dynamics
algebraic
Advisor: Jaksch, D
Buca, B
“Floating with the words”: Year 2 children’s perspectives on reading in the UK

This case study investigates 6- to 7-year-old children’s (n=14) attitudes towards reading and learning to read, and their definitions of a reader and reading in order to identify ways of increasing children’s motivation to read for pleasure which will be beneficial to their language skills and learning across the curriculum (Clark & Rumbold, 2006; Castles et al., 2018). This study’s aim is threefold. Firstly, to investigate the reading lives and attitudes of children at a British Ofsted rated Outstanding school which prides itself in fostering reading for pleasure (RfP). Secondly, this study aims to promote children’s voices by exploring their perspectives on reading in their own words. Thirdly, this research intends to ascertain whether the ‘Rivers of Reading’ (RoR) exercise may be usefully adapted to help younger participants talk about their experiences of learning to read and their attitudes towards reading. Participants offered insights into their attitudes towards pedagogical practices in literacy instruction and from this, it was possible to extrapolate practices that increase or decrease reading motivation by linking it to the literature on reading motivation and RfP pedagogical principles. These findings could be usefully implemented in other schools in the UK and add to the theoretical debate about the process of reading and learning to read. Furthermore, the successful adaptation of the RoR exercise, combined with in-depth qualitative interviews, offers a model for innovative rights-based research that places value on what children have to say.

Keywords: Reading attitudes
Literacy
Children's voices
Reading motivation
Year 2
River's of Reading
Reading for Pleasure
Reading engagement
Advisor: Faitaki, F
The effect of English videos with different types of subtitles and glosses on vocabulary learning of Chinese ESL learners

There is growing interest in research focusing on the effect of subtitled videos on second language (L2) vocabulary learning. While a large number of studies have investigated the benefits of L2 subtitles, few studies have examined L1 subtitles and dual subtitles and compared the effects of the subtitles in different languages. What’s more, glosses in subtitles are paid more attention to, because they stimulate learners’ attention to the novel words and provide the meaning of the words to scaffold acquisition of form-meaning links. The present study investigated the effects of five different types of subtitles (L2 subtitles, L1 subtitles, dual subtitles, L2 subtitles + L2 glosses, and L2 subtitles + L1 glosses). A total of 314 Chinese middle school students who are beginner learners of English as a second language (ESL) were randomly assigned to one of the five conditions and watched two videos with different types of subtitles. For each video, 10 target words were included, and there were 20 target words in total. An unexpected post-test measuring the participants’ word form and word meaning learning was administered immediately after the participants watched each video. Results show that the group with L2 subtitles and L1 glosses significantly outperformed the L1 subtitles group in the word form tests, while there was no significant difference between any other groups. For word meaning learning, it was found that both the L1 subtitles group and the dual subtitles group significantly outperformed the L2 subtitles group. What’s more, the group with L2 subtitles and L1 glosses significantly outperformed every other group in the word meaning test. However, the group with L2 subtitles and L2 glosses had no significant difference from the L2 subtitles group without glosses. This interventional study contributes to the literature by providing evidence which suggests that L1 subtitles may benefit word meaning learning, and that glosses can draw learners’ attention to the target words and scaffolds word form learning. Pedagogical implications on the use of subtitles and glosses in L2 learning videos are provided.

Keywords: caption
subtitle
incidental vocabulary learning
second language video
gloss
Advisor: Booton, S