Miracle-dz/UniFAR-FTUs huggingface dataset:
On a class of discrete time renewal risk models

We consider a class of compound renewal (Sparre Andersen) risk process with claim waiting times having a discrete K m distribution, i.e., the probability generating function (p.g.f.) of the distribution function is a ratio of two polynomials of order . The classical compound binomial risk model is a special case when m=1. A recursive formula is derived for the expected discounted penalty (Gerber-Shiu) function, which can be used to analyze many quantities associated with the time of ruin, e.g., the surplus before ruin, the deficit at ruin, and the claim causing ruin. Detailed discussions are given in two special cases: claim sizes are rationally distributed, or the claim sizes distribution has a finite support.
Interfacial and annealing effects on magnetic properties of CoFeB thin films

The interfacial and annealing effects on magnetic properties of CoFeB thin films with Ta and Ru interfaces were investigated. It is found that the thickness of magnetically dead layer of as-deposited CoFeB film strongly depends on the interfaces. After annealing above 150°C boron atoms seem to diffuse out of CoFeB film and the effective saturation magnetization of CoFeB film increases with annealing temperature and annealing time. In addition, CoFeB film with Ta interfaces remains amorphous while that with Ru interfaces starts to crystallize during the annealing above 250°C. Furthermore, the annealing-induced anisotropy field of CoFeB film can be modified by using different seed and capping materials.
Approximations of Markov Chains and High-Dimensional Bayesian Inference

The Markov Chain Monte Carlo method is the dominant paradigm for posterior computation in Bayesian analysis. It has long been common to control computation time by making approximations to the Markov transition kernel. Comparatively little attention has been paid to convergence and estimation error in these approximating Markov Chains. We propose a framework for assessing when to use approximations in MCMC algorithms, and how much error in the transition kernel should be tolerated to obtain optimal estimation performance with respect to a specified loss function and computational budget. The results require only ergodicity of the exact kernel and control of the kernel approximation accuracy. The theoretical framework is applied to approximations based on random subsets of data, low-rank approximations of Gaussian processes, and a novel approximating Markov chain for discrete mixture models.
Stability and bifurcation of spatially coherent solutions of the damped-driven NLS equation

An analytical study is conducted of the structure, stability, and bifurcation of the spatially dependent time-periodic solutions of the damped-driven sine-Gordon equation in the nonlinear Schrodinger approximation. Locked states are found for which the spatial structure consists of coherent excitations localized about $x = 0$ or $L/2$. A bifurcation analysis reveals the relationship of these spatially localized solutions to the spatially independent ones and provides a cutoff wavenumber above which there are no spatially dependent solutions; this establishes an upper bound on the number of local excitations comprising the spatial pattern. A linear stability analysis shows that the spatially localized solutions undergo a Hopf bifurcation to temporal quasi-periodicity as the driver amplitude $\Gamma $ is increased. For sufficiently high driver frequencies, the temporally periodic solution regains its stability (via another Hopf bifurcation) in a $\Gamma $-window of finite width before undergoing a third Hop.
RustSmith A Randomized Program Generator for Rust

Rust is a modern, popular programming language designed specifically with performance and reliability in mind, and is now being rapidly adopted both in industry and academia. Rust aims to guarantee memory safety through “a rich type system and ownership model” which enable developers using Rust to “eliminate many classes of bugs at compile-time” [1]. As such, ensuring Rust’s compiler (rustc) is reliable and bug-free is critical. This project presents RustSmith, a novel Rust compiler fuzzer which aims to test the Rust compiler by randomly generating valid, interesting and diverse Rust programs. RustSmith takes inspiration from previous successful techniques for compiler testing, and adapts them to the context of Rust. In addition, RustSmith utilizes novel techniques that enable it to effectively test Rust-specific features such as ownership, borrowing and lifetimes. RustSmith breaks new ground as the first fuzzer for the Rust programming language [2] capable of generating valid programs that exercise a number of Rust-specific concepts and features. RustSmith is capable of generating files that cover over half of the optimizations module in Rust’s compiler source code, along with successfully producing bug-inducing files that detect both historic and current bugs in the Rust compiler. Additionally, we find that RustSmith successfully covers “blind-spots” (which are areas the official test suite is unable to cover) in 9 different optimizations used by the Rust compiler. Acknowledgements I would like to thank my supervisor, Professor Alastair Donaldson, for their invaluable guidance, constant enthusiasm and insightful thoughts and ideas throughout the development of the project. I would also like to thank my second marker, Professor Cristian Cadar, for not only giving feedback for the interim report, but also teaching the Software Reliability course that provided me with the basis to complete this project. Finally, I would like to thank my friends and family for their immense support throughout the degree and this project, providing the support, encouragement and motivation I needed to complete this project.
Processing SPARQL TOP-k Queries Online with Web Preemption

Processing top- 𝑘 queries on public online SPARQL endpoints often runs into fair use policy quotas and does not complete. Indeed, existing endpoints mainly follow the traditional materialize-and-sort strategy. Although restricted SPARQL servers ensure the termination of top- 𝑘 queries without quotas enforcement, they follow the materialize-and-sort approach, resulting in high data transfer and poor performance. In this paper, we propose to extend the Web preemption model with a preemptable partial top- 𝑘 operator. This operator drastically reduces data transfer and significantly improves query execution time. Experimental results show a reduction in data transfer by a factor of 100 and a reduction of up to 39% in Wikidata query execution time.
Automated motion estimation from M-mode echocardiograms

New algorithms for motion estimation from sequential images are applied to M-mode echocardiograms. Motion is estimated by finding a transformation which relates an initial and final image. The transformation includes a 1D displacement field and modifications in image intensity. The displacements and intensity modifications are adjusted iteratively using the method of convex projections applied to linearized constraint equations. Preliminary results indicate that this method is effective in estimating motion from M-mode images. Computed velocity vectors are approximately tangent to the visible heart wall boundary trajectories. Motion computed from a single reference time appears to provide a means for tracking individual heart wall boundaries.
Membrane Contact Sites in Autophagy

Eukaryotes utilize different communication strategies to coordinate processes between different cellular compartments either indirectly, through vesicular transport, or directly, via membrane contact sites (MCSs). MCSs have been implicated in lipid metabolism, calcium signaling and the regulation of organelle biogenesis in various cell types. Several studies have shown that MCSs play a crucial role in the regulation of macroautophagy, an intracellular catabolic transport route that is characterized by the delivery of cargoes (proteins, protein complexes or aggregates, organelles and pathogens) to yeast and plant vacuoles or mammalian lysosomes, for their degradation and recycling into basic metabolites. Macroautophagy is characterized by the de novo formation of double-membrane vesicles called autophagosomes, and their biogenesis requires an enormous amount of lipids. MCSs appear to have a central role in this supply, as well as in the organization of the autophagy-related (ATG) machinery. In this review, we will summarize the evidence for the participation of specific MCSs in autophagosome formation, with a focus on the budding yeast and mammalian systems.
ALGORITHMIC DIFFERENTIATION FOR AN EFFICIENT CFD SOLVER

We illustrate the beneﬁts of Algorithmic Diﬀerentiation (AD) for the development of aerodynamic ﬂow simulation software. In reﬁning the architecture of the elsA CFD solver, developed jointly by ONERA and Safran, we consider AD as a key technology to cut development costs of some derivatives of interest, namely the tangent, adjoint, and Jacobian. We ﬁrst recall the mathematical background of CFD applications which involve these derivatives. Then, we brieﬂy present the software architecture of elsA (Cambier et al. [12]) and the design choices which give it its HPC capability while highlighting how these choices strongly constrain the applicability of AD. To meet our eﬃciency requirements, we select the Source-Transformation approach to AD through the Tapenade tool which is justiﬁed by a series of experiments and benchmarks. Finally, we present results on large scale conﬁgurations.
A Novel Model Using AAV9-Cre to Knockout Adult Leydig Cell Gene Expression Reveals a Physiological Role of Glucocorticoid Receptor Signalling in Leydig Cell Function

Glucocorticoids are steroids involved in key physiological processes such as development, metabolism, inflammatory and stress responses and are mostly used exogenously as medications to treat various inflammation-based conditions. They act via the glucocorticoid receptor (GR) expressed in most cells. Exogenous glucocorticoids can negatively impact the function of the Leydig cells in the testis, leading to decreased androgen production. However, endogenous glucocorticoids are produced by the adrenal and within the testis, but whether their action on GR in Leydig cells regulates steroidogenesis is unknown. This study aimed to define the role of endogenous GR signalling in adult Leydig cells. We developed and compared two models; an inducible Cre transgene driven by expression of the Cyp17a1 steroidogenic gene (Cyp17-iCre) that depletes GR during development and a viral vector-driven Cre (AAV9-Cre) to deplete GR in adulthood. The delivery of AAV9-Cre ablated GR in adult mouse Leydig cells depleted Leydig cell GR more efficiently than the Cyp17-iCre model. Importantly, adult depletion of GR in Leydig cells caused reduced expression of luteinising hormone receptor (Lhcgr) and of steroidogenic enzymes required for normal androgen production. These findings reveal that Leydig cell GR signalling plays a physiological role in the testis and highlight that a normal balance of glucocorticoid activity in the testis is important for steroidogenesis.
Synoptic‐scale precursors of the East Asia/Pacific teleconnection pattern responsible for persistent extreme precipitation in the Yangtze River Valley

Synoptic‐scale precursors of the typical East Asia/Pacific (EAP) teleconnection pattern responsible for persistent extreme precipitation events (PEPEs) in the Yangtze River Valley (YRV) are investigated, based on a composite analysis. The results reveal that, about one week prior to PEPEs, a blocking high develops near the Sea of Okhotsk owing to an eastward energy dispersion and further strengthens markedly due to poleward energy dispersion from low latitudes. Subsequently, a meridional tripole structure of the typical EAP pattern becomes well established by this blocking, along with a westward‐migrated strong negative anomaly at midlatitudes/positive anomaly at lower latitudes. In the lower troposphere, a westward‐progressive anomalous anticyclone–cyclone pair can be identified up to about a week prior to PEPEs, contributing to greatly enhanced moisture transport towards the YRV with a magnitude anomaly over three standard deviations above normal. A midlatitude anomalous cyclone associated with the EAP pattern evolution and the eastward‐extended South Asia High combine to provide favourable upper‐level divergence. Correspondingly, strong ascent of low‐level warm/moist air along a quasi‐stationary front leads to PEPEs in the YRV. A contrastive analysis between evolution of typical wet and dry EAP regimes indicates that EAP‐induced PEPEs are more likely to occur in the YRV, with the ridge of the western Pacific subtropical high typically staying around the northeastern quadrant of the South China Sea. This contrasting analysis also highlights the importance of the upstream pre‐existing ridge to early strengthening of the Okhotsk blocking.
Endogenous Macrodynamics in Algorithmic Recourse

Existing work on Counterfactual Explanations (CE) and Algorithmic Recourse (AR) has largely focused on single individuals in a static environment: given some estimated model, the goal is to find valid counterfactuals for an individual instance that fulfill various desiderata. The ability of such counterfactuals to handle dynamics like data and model drift remains a largely unexplored research challenge. There has also been surprisingly little work on the related question of how the actual implementation of recourse by one individual may affect other individuals. Through this work, we aim to close that gap. We first show that many of the existing methodologies can be collectively described by a generalized framework. We then argue that the existing framework does not account for a hidden external cost of recourse, that only reveals itself when studying the endogenous dynamics of recourse at the group level. Through simulation experiments involving various state-of-the-art counterfactual generators and several benchmark datasets, we generate large numbers of counterfactuals and study the resulting domain and model shifts. We find that the induced shifts are substantial enough to likely impede the applicability of Algorithmic Recourse in some situations. Fortunately, we find various strategies to mitigate these concerns. Our simulation framework for studying recourse dynamics is fast and open-sourced.
An Auditable Confidentiality Protocol for Blockchain Transactions

Blockchain exposes all users’ transaction data to the public, including account balances, asset holdings, trading history, etc. Such data exposure leads to potential security and personal privacy risks that restrict blockchain from broader adoption. Although some existing projects focus on single-chain confidential payment, no existing cross-chain system supports private transactions yet, which is incompatible with privacy regulations such as GDPR. Also, current confidential payment systems require users to pay high extra fees. However, a private and anonymous protocol encrypting all transaction data raises concerns about malicious and illegal activities since the protocol is difficult to audit. We need to balance privacy and auditability in blockchain. We propose an auditable and affordable protocol for cross-chain and single-chain transactions. This protocol leverages zero-knowledge proofs to encrypt transactions and perform validation without disclosing sensitive users’ data. To meet regulations, each auditor from an auditing committee will have an encrypted secret share of the transaction data. Auditors may view the private transaction data only if a majority of the committee agrees to decrypt the data. We employ a ZK-rollup scheme by processing multiple transactions in batches, which reduces private transaction costs to 90% lower compared with solutions without ZK-rollup. We implemented the proposed scheme using Zokrates and Solidity and evaluated the protocol on the Ethereum test network, and the total one-to-one private transactions cost only 5 seconds. We also proved the security of the protocol utilizing the standard real/ideal world paradigm.
Design of Reservoirs Enabling Stress-Induced Sequential Release Systems

Mechanical stress is recognized as a principle for opening enclosed compartments through compression, stretching, or shear, eventually resulting in the onset of a diffusion-controlled release. Here, we hypothesized that the geometrical design of cavities (cut-outs) introduced as containers in elastic polymer substrates and sealed with a brittle coating layer would enable a pre-defined release of different compounds by stress concentration phenomena. Design criteria such as cut-out shapes, orientations, and depths were initially assessed for suitably different stress concentrations in computational models. In substrates fabricated from polydimethylsiloxane by photolithographic techniques, the local strains at horizontal rectangular, circular, and vertical rhombus-shaped cut-outs systematically increased under horizontal stretching as proposed. When filled with model compounds and coated with poly(n-butyl cyanoacrylate), a pre-defined induced breakage of the coating and compound release was confirmed upon continuous uniaxial stretching. This proof of concept demonstrates how device design and functions interlink and may motivate further exploration in technology and medicine for deformation-induced on-demand dosage applications.
Local Attraction of Substrates and Co-Substrates Enhances Weak Acid and Base Transmembrane Transport

The transmembrane transport of weak acid and base metabolites depends on the local pH conditions that affect the protonation status of the substrates and the availability of co-substrates, typically protons. Different protein designs ensure the attraction of substrates and co-substrates to the transporter entry sites. These include electrostatic surface charges on the transport proteins and complexation with seemingly transport-unrelated proteins that provide substrate and/or proton antenna, or enzymatically generate substrates in place. Such protein assemblies affect transport rates and directionality. The lipid membrane surface also collects and transfers protons. The complexity in the various systems enables adjustability and regulation in a given physiological or pathophysiological situation. This review describes experimentally shown principles in the attraction and facilitation of weak acid and base transport substrates, including monocarboxylates, ammonium, bicarbonate, and arsenite, plus protons as a co-substrate.
Role of worker ﬂows in the relationship between job oﬀers and employment

This study investigates the mechanism determining changes in job offers and analyzes the role of worker flows in the relationship between job offers and employment. It applies a queueing system to dynamic general equilibrium models and analyzes economic fluctuations. The queueing system helps in considering the relationship between job offers and employment and changes in job offers in response to shocks. The numerical simulations indicate that worker flows influence changes in job offers in response to a productivity shock. Although employment fluctuations remain constant, changes in job offers amplify when fewer workers join and/or more workers leave the firm, whereas they decrease when more workers join and/or fewer workers leave. The shock responses of other variables in each model are in line with the reactions of the standard dynamic general equilibrium models. These findings provide important insights into labor market dynamics.
Modern Canonical Quantum General Relativity: Refined algebraic quantisation (RAQ) and direct integral decomposition (DID)

This is an introduction to the by now fifteen years old research field of canonical quantum general relativity, sometimes called "loop quantum gravity". The term "modern" in the title refers to the fact that the quantum theory is based on formulating classical general relativity as a theory of connections rather than metrics as compared to in original version due to Arnowitt, Deser and Misner. Canonical quantum general relativity is an attempt to define a mathematically rigorous, non-perturbative, background independent theory of Lorentzian quantum gravity in four spacetime dimensions in the continuum. The approach is minimal in that one simply analyzes the logical consequences of combining the principles of general relativity with the principles of quantum mechanics. The requirement to preserve background independence has lead to new, fascinating mathematical structures which one does not see in perturbative approaches, e.g. a fundamental discreteness of spacetime seems to be a prediction of the theory providing a first substantial evidence for a theory in which the gravitational field acts as a natural UV cut-off. An effort has been made to provide a self-contained exposition of a restricted amount of material at the appropriate level of rigour which at the same time is accessible to graduate students with only basic knowledge of general relativity and quantum field theory on Minkowski space.
Three-point temperature anisotropies in WMAP: Limits on CMB non-Gaussianities and nonlinearities

We present a study of the 3-pt angular correlation function w_3= of (adimensional) temperature anisotropies measured by the Wilkinson Microwave Anisotropy Probe (WMAP). Results can be normalized to the 2-point function w_2 = in terms of the hierarchical: q_3 ~ w_3/w_2^2 or dimensionless: d_3 ~ w_2/w_2^{3/2}$ amplitudes. Strongly non-Gaussian models are generically expected to show d_3 > 1 or q_3 > 10^3 d_3. Unfortunately, this is comparable to the cosmic variance on large angular scales. For Gaussian primordial models, q_3 gives a direct measure of the non-linear corrections to temperature anisotropies in the sky: delta = delta_L + f_{NLT} (delta_L^2 - ) with f_{NLT} = q_3/2 for the leading order term in w_2^2. We find good agreement with the Gaussian hypothesis d_3 ~ 0 within the cosmic variance of LCDM simulations (with or without a low quadrupole). The strongest constraints on q_3 come from scales smaller than 1 degree. We find q_3 =19 +/-141 for (pseudo) collapsed configurations and an average of q_3 = 336 +/-218 for non-collapsed triangles. The corresponding non-linear coupling parameter, f_{NL}, for curvature perturbations Phi, in the Sachs-Wolfe (SW) regime is: f_{NL}^{SW} = q_3/6, while on degree scales, the extra power in acoustic oscillations produces f_{NL} ~ q_3/30 in the LCM model. Errors are dominated by cosmic variance, but for the first time they begin to be small enough to constrain the leading order non-linear effects with coupling of order unity.
Progress in carbon nanotube based nanoelectromechanical systems synthesis

We present a revised process flow for the integration of individual single‐walled carbon nanotubes into microelectromechanical systems. The revision consists in a re‐ordered process sequence which consider‐ably increases the device yield. Thermal catalytic chemical vapor deposition of single‐walled carbon nanotubes is performed conjunctly with annealing as the very last process step. Maskless catalyst deposition is demonstrated to produce individual single‐walled carbon nanotubes with good location and orientation control by shaping the catalyst support. Straining experiments showed that the mechanical anchoring between the tube and the support can be sufficient. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)