Miracle-dz/UniFAR-FTUs huggingface dataset:
A discontinuous Galerkin method for solving the fluid and magnetohydrodynamic equations in astrophysical simulations

A discontinuous Galerkin (DG) method suitable for large-scale astrophysical simulations on Cartesian meshes as well as arbitrary static and moving Voronoi meshes is presented. Most major astrophysical fluid dynamics codes use a finite volume (FV) approach. We demonstrate that the DG technique offers distinct advantages over FV formulations on both static and moving meshes. The DG method is also easily generalized to higher than second-order accuracy without requiring the use of extended stencils to estimate derivatives (thereby making the scheme highly parallelizable). We implement the technique in the AREPO code for solving the fluid and the magnetohydrodynamic (MHD) equations. By examining various test problems, we show that our new formulation provides improved accuracy over FV approaches of the same order, and reduces post-shock oscillations and artificial diffusion of angular momentum. In addition, the DG method makes it possible to represent magnetic fields in a locally divergence-free way, improving the stability of MHD simulations and moderating global divergence errors, and is a viable alternative for solving the MHD equations on meshes where Constrained-Transport (CT) cannot be applied. We find that the DG procedure on a moving mesh is more sensitive to the choice of slope limiter than is its FV method counterpart. Therefore, future work to improve the performance of the DG scheme even further will likely involve the design of optimal slope limiters. As presently constructed, our technique offers the potential of improved accuracy in astrophysical simulations using the moving mesh AREPO code as well as those employing adaptive mesh refinement (AMR).
A Study on The Crack Behavior of Baggase-Polyester Composites

The development of composite technology has begun to change nowadays, from composite fiber-synthesized to composite natural fiber fabrics. Natural baggase fiber has the opportunity to be developed as a strengthening medium in polymer resins. The purpose of this study were to know the effect of fiber orientation to maximum critical load for different initial crack lengths, to know elastic energy of composite material having fiber orientation varied at the time of loading and to know the effect of fiber orientation on fracture toughness for composite material. In this paper, it’s used 1.5mm diameter sugarcane fibers and the polyester matrix. The fraction volume of fiber and resin used is 5%: 95%. Fiber is given 20% NaOH treatment. Then the fiber is arranged with orientation 0/90o and 0/45o. While the bending test specimen is in accordance with ASTM-D5045 standard, the size of the specimen dimension is 125 mm long, 30 mm wide and 10 mm thick; with crack variations are 7mm, 9mm, 11mm, 13mm, and 15mm. It’s could be concluded that the critical load will decrease as the initial crack length increases. Composite material with 0/90o fiber orientation has elastic energy greater than composite with 45o fiber orientation. And crack propagation rate in composite material with fiber orientation 0/90o is faster than composite with 0/45o orientation.
Holographic Fluctuations from Unitary de Sitter Invariant Field Theory

We continue the study of inflationary fluctuations in Holographic Space Time models of inflation. We argue that the holographic theory of inflation provides a physical context for what is often called dS/CFT. The holographic theory is a quantum theory which, in the limit of a large number of e-foldings, gives rise to a field theory on $S^3$, which is the representation space for a unitary representation of SO(1,4). This is not a conventional CFT, and we do not know the detailed non-perturbative axioms for correlation functions. However, the two- and three-point functions are completely determined by symmetry, and coincide up to a few constants (really functions of the background FRW geometry) with those calculated in a single field slow-roll inflation model. The only significant deviation from slow roll is in the tensor fluctuations. We predict zero tensor tilt and roughly equal weight for all three conformally invariant tensor 3-point functions (unless parity is imposed as a symmetry). We discuss the relation between our results and those of Maldacena, McFadden, Skenderis, and others. Current data can be explained in terms of symmetries and a few general principles, and is consistent with a large class of models, including HST.
A Security Analysis of the WPA-TKIP and TLS Security Protocols

This dissertation analyzes the security of popular network protocols. First we investigate the Wi-Fi Protected Access Temporal Key Integrity Protocol (WPA-TKIP), and then we study the security of the RC4 stream cipher in both WPA-TKIP and the Transport Layer Security (TLS) protocol. We focus on these protocols because of their popularity. In particular, around November 2012, WPA-TKIP was used by two-thirds of encrypted Wi-Fi networks, and it is currently still used by more than half of all encrypted networks. Similarly, around 2013, RC4 was used in half of all TLS connections. Finally, with as goal to implement reliable proof-of-concepts for some of our attacks against WPA-TKIP, we also study physical layer security aspects of Wi-Fi. In the first part of this dissertation we focus on WPA-TKIP when used to protect unicast Wi-Fi traffic. Here we demonstrate how fragmentation of Wi-Fi frames can be used to inject an arbitrary number of packets, and we show how this attack can be applied in practice by performing a portscan on any client connected to the network. Then we propose a technique to decrypt arbitrary packets sent towards a client. Our technique first resets the internal state of the Michael algorithm, and abuses this to make victims forward packets to a server under control of the adversary, effectively decrypting the packets. We also present a novel Denial of Service (DoS) attack that requires the injection of only two frames every minute. Additionally, we discover that several network cards use flawed and insecure implementations of WPA-TKIP. In the second part of the dissertation, our goal is to attack WPA-TKIP when used to protect broadcast and multicast traffic, i.e., group traffic. This is important since, even in 2016, more than half of all encrypted Wi-Fi networks still protect group traffic using WPA-TKIP. To carry out our attack in a general setting, we must be able to reliably block certain packets from arriving at their destination, preferably using cheap commodity Wi-Fi devices. Hence we first study low-layer aspects of the Wi-Fi protocol. Surprisingly, we found that commodity devices allow us to violate several assumptions made by the Wi-Fi
Remembering to remember : how do children develop the skills necessary to organise their future behaviour?.

The successful organisation of future behaviour is a fundamental skill underpinning daily life. Each day we plan to perform multiple actions and activities ahead of time, and execute these planned actions at an appropriate time and place. The cognitive processes underlying such ‘future-oriented’ skills have been the recent focus of adult studies; surprisingly little research has investigated the development of these abilities in children. Adult research studies have successfully employed ‘multitasking paradigms’ to study these skills and have identified a number of cognitive processes that support the organisation of future behaviour. The focus of this research was to use multitasking as a methodology to assess the cognitive skills involved in organisation of future behaviour in childhood. We developed the Battersea Multitask Paradigm, a novel test to assess future organisation skills in children and adults. The paradigm also enabled us to investigate the cognitive processes that underlie the organisation of future action, including retrospective memory, prospective memory (memory for intentions), planning and executive functions. We tested groups of children aged 6, 8, 10, 12 and 14 years, and a group of young adults, and found significant developmental differences in multitask performance. These findings are interpreted as evidence that the ability to organise future behaviour develops from 6 years of age into young adulthood. We also examined the developmental trajectories of the cognitive processes underlying multitasking. Results indicate that children under 10 years old find it difficult to co-ordinate performance across multiple tasks, and their performance declines when they are asked to do so. This is likely to represent age-related differences in prospective memory and information processing capacity. In contrast, performance differences between older children and adults are attributable to developments in executive strategy use. The ability to organise future behaviour can be impaired in children with developmental disorders. We investigated multitasking in a group of boys with autism spectrum disorder. These boys had significant difficulties organising future activities in their day-to-day lives, and this was reflected in multitask performance decrements relative to typically developing controls. The Battersea Multitask Paradigm is a novel test with the unusual quality of being useable and challenging to 6 year olds as well as to adults and atypical populations, which can reveal the component parts of the cognitive processes underlying the organisation of future-oriented behaviour.
Complex G 2 and Associative Grassmannian

We obtain defining equations of the smooth equivariant compactification of the Grassmannian of the complex associative 3-planes in C, which is the parametrizing variety of all quaternionic subalgebras of the algebra of complex octonions O ∼= C. By studying the torus fixed points, we compute the Poincaré polynomial of the compactification.
Iron Kα line of boson stars

The present paper is a sequel to our previous work [1] in which we studied the iron Kα line expected in the reflection spectrum of Kerr black holes with scalar hair. These metrics are solutions of Einstein's gravity minimally coupled to a massive, complex scalar field. They form a continuous bridge between a subset of Kerr black holes and a family of rotating boson stars depending on one extra parameter, the dimensionless scalar hair parameter q, ranging from 0 (Kerr black holes) to 1 (boson stars). Here we study the limiting case q = 1, corresponding to rotating boson stars. For comparison, spherical boson stars are also considered. We simulate observations with XIS/Suzaku. Using the fact that current observations are well fit by the Kerr solution and thus requiring that acceptable alternative compact objects must be compatible with a Kerr fit, we find that some boson star solutions are relatively easy to rule out as potential candidates to explain astrophysical black holes, while other solutions, which are neither too dilute nor too compact are more elusive and we argue that they cannot be distinguished from Kerr black holes by the analysis of the iron line with current X-ray facilities.
Local Patch Similarity Ranked Voxelwise STAPLE on Magnetic Resonance Image Hippocampus Segmentation

The segmentation and labeling of sub-cortical structures of interest are important tasks for the assessment of morphometric features in quantitative magnetic resonance (MR) image analysis. Recently, multi-atlas segmentation methods with statistical fusion strategy have demonstrated high accuracy in hippocampus segmentation. While, most of the segmentations rarely consider spatially variant model and reserve all segmentations. In this study, we propose a novel local patch-based and ranking strategy for voxelwise atlas selection to extend the original Simultaneous Truth and Performance Level Estimation (STAPLE) algorithm. The local ranking strategy is based on the metric of normalized cross correlation (NCC). Unlike its predecessors, this method estimates the fusion of each voxel patch-by-patch and makes use of gray image features as a prior. Validation results on 33 pairs of hippocampus MR images show good performance on the segmentation of hippocampus.
Doc2EDAG: An End-to-End Document-level Framework for Chinese Financial Event Extraction

Most existing event extraction (EE) methods merely extract event arguments within the sentence scope. However, such sentence-level EE methods struggle to handle soaring amounts of documents from emerging applications, such as finance, legislation, health, etc., where event arguments always scatter across different sentences, and even multiple such event mentions frequently co-exist in the same document. To address these challenges, we propose a novel end-to-end model, Doc2EDAG, which can generate an entity-based directed acyclic graph to fulfill the document-level EE (DEE) effectively. Moreover, we reformalize a DEE task with the no-trigger-words design to ease the document-level event labeling. To demonstrate the effectiveness of Doc2EDAG, we build a large-scale real-world dataset consisting of Chinese financial announcements with the challenges mentioned above. Extensive experiments with comprehensive analyses illustrate the superiority of Doc2EDAG over state-of-the-art methods. Data and codes can be found at https://github.com/dolphin-zs/Doc2EDAG.
Collision-free Optimal Trajectory Planning in a Multiple Robot System

We address the problem of motion planning and cooperative control in a multiple robot system. We study the problem of cooperative planning in order to simulate the algorithm for concurrent assignment and planning of trajectories (CAPT) for a team of robots. CAPT algorithm addresses two challenges: a. finding a fitting allotment of robots to a given goal locations, and b. generation of collision-free, time parametrized trajectories for every robot. There exists two variations of the CAPT problem. c-CAPT is a complete, centralized algorithm with collision-free optimal solution to a distributed problem in an obstacle-free environment. D-CAPT is a decentralized algorithm that provides suboptimal results in an obstacle-free environment. We extend this to an obstacle-course environment. For this, we propose a complete algorithm: Goal Assignment and Planning (GAP) that computes the optimal trajectories and assignments of robots to goals with complex vehicle dynamics and cost functions. The computational complexity of this algorithm is shown to be cubic, substantially better than the expected exponential complexity associated with planning in the joint state space and assignment of goals to robots. Finally, we illustrate the algorithms and resulting performance through simulation. Keywords—Multi-robot trajectory planning, Role assignment.
Evolving heterogeneous neural networks for classification problems

This paper describes research investigating the behavior of feedforward neural networks with different neuron types when applied to classification problems. For this purpose, a hierarchical evolutionary technique (HCGA) was employed towards the automatic design of heterogeneous neural nets. In an upper level, a genetic algorithm keeps in charge of building the net topology by choosing its hidden layer neurons (possibly with distinct features). Neural nets compete against each other across the GA generations. In a bottom level, a coevolutionary approach was selected in order to train the network by adjusting both the activation function parameters of the hidden neurons and its incoming input weights. This tuning is done by means of a cooperative process where the neurons receive their fitnesses according to the average fitness of the networks in which they participate.
Explicit travelling waves and invariant algebraic curves

We introduce a precise definition of algebraic travelling wave solution of n-th order partial differential equations and prove that the only algebraic travelling waves solutions for the celebrated Fisher–Kolmogorov equation are the ones found in 1979 by Ablowitz and Zeppetella. This question is equivalent to study when an associated one-parameter family of planar ordinary differential systems has invariant algebraic curves.
Building versatile bipartite probes for quantum metrology

We consider bipartite systems as versatile probes for the estimation of transformations acting locally on one of the subsystems. We investigate what resources are required for the probes to offer a guaranteed level of metrological performance, when the latter is averaged over specific sets of local transformations. We quantify such a performance via the average skew information (AvSk), a convex quantity which we compute in closed form for bipartite states of arbitrary dimensions, and which is shown to be strongly dependent on the degree of local purity of the probes. Our analysis contrasts and complements the recent series of studies focused on the minimum, rather than the average, performance of bipartite probes in local estimation tasks, which was instead determined by quantum correlations other than entanglement. We provide explicit prescriptions to characterize the most reliable states maximizing the AvSk, and elucidate the role of state purity, separability and correlations in the classification of optimal probes. Our results can help in the identification of useful resources for sensing, estimation and discrimination applications when complete knowledge of the interaction mechanism realizing the local transformation is unavailable, and access to pure entangled probes is technologically limited.
Witnessing entanglement in phase space using inefficient detectors

We propose a scheme for witnessing entanglement in phase space by significantly inefficient detectors. The implementation of this scheme does not require any additional process for correcting errors, in contrast to previous proposals. Moreover, it allows us to detect entanglement without full a priori knowledge of the detection efficiency. It is shown that entanglement in single-photon entangled and two-mode squeezed states can be witnessed with detection efficiency as low as 40%. Our approach enhances the possibility of witnessing entanglement in various physical systems using current detection technologies.
Capital In ows and the US Housing Boom

We estimate an open-economy VAR model to study the e¤ect of capital-inow shocks on the US housing market. We look at di¤erent external shocks which generate capital inows to the US, in particular savings glut shocks and foreign monetary policy expansions. The shocks are identi ed with theoretically-robust sign restrictions derived from a standard Dynamic Stochastic General Equilibrium model. Our results suggest that capital-inow shocks driven by savings glutshocks have a positive and persistent e¤ect on real house prices and real residential investment. Key words: house prices, capital inows JEL Classi cation: F3, F4 The authors wish to thank Andrea Ferrero for sharing his codes and giving useful advice. Martin Brooke, Phil Evans, Linda Goldberg, Glenn Hoggarth, Nobuhiro Kiyotaki, Gary Koop, Haroon Mumtaz, Adrian Pagan, Ugo Panizza, Matthias Paustian, Hashem Pesaran and Cédric Tille also made helpful suggestions. Andreas Baumann and Richard Edghill provided excellent assistance with the data. yKings College London; IZA. E-mail: lipa.sa@kcl.ac. uk. zBank of England. Email: Tomasz.Wieladek@bankofengland.co.uk.
Odtwarzanie prędkości PMSM z wykorzystaniem obserwatora

To determine the position of the motor shaft the permanent magnet synchronous, in the case of non-zero speed, for example, you can use the method based on estimation instantaneous value of electromotive force. On their basis, the shaft position is determined. Calculating the velocity directly from the position, typically forces the use of filters in the speed control loop, which introduces an additional delay, resulting in the decreasing of the drive dynamics. The paper presents a method of determining a speed, which do not have that drawback. (Speed estimation of the PMSM using back EMF observer). Słowa kluczowe: PMSM, sterowanie bezczujnikowe, obserwator.
Trends in automating physical database design

A database administrator (DBA) must make many decisions about what is the best decision for a database and its users - including what is the best physical DB design decision. The DBA must determine what auxiliary data structures to create - such as indexes and materialized views - as well as the optimal way to partition each table in a shared-nothing partitioned system, to maximize workload performance while minimizing any increase in disk space or maintenance costs. Given the number of possible configurations, the possible interactions between each choice, and the associated constraints on the decision, the problem of selecting an optimal design is daunting for even the most skilled DBA. It has long been recognized that DBAs need tools to help them make these complex decisions, but until recently little progress was made. We present our vision for the future of automating physical DB design, and contrast it with previous attempts at solving this problem.
Achieving adaptable behaviour in intelligent rooms using curious supervised learning agents

Multiple devices, both hardware and software, may come and go at any time in a given room. Software controlling the behaviour of these devices must be able to adapt to encompass new devices or the removal of existing devices. This paper presents a model for curious, supervised learning agents that address the issue of adaptability at a behavioural level in an intelligent room. Curious, supervised learning agents comprise a curiosity module and a supervised learning algorithm. The curiosity module identifies interesting devices on which to focus the agent’s learning. The supervised learning component realises behaviours by observing, modelling and mimicking human actions. Our framework is demonstrated in a virtual meeting room in Second Life. We show that the curious learning agent can adapt its behaviour to identify new learning goals in response to new devices and activities.
Design and Synthesis of a Highly Simplified Pateamine Analogue

Pateamine (1) is a natural product from the marine sponge Mycale hentscheli that exhibits potent anticancer properties, and has potential as an antiviral agent, and in preventing the muscle wasting disorder cachexia. This biological activity of pateamine is due to its ability to inhibit the eukaryotic initiation factor eIF4A, which leads to the formation of stress granules, the inhibition of protein synthesis, and ultimately cell death. Unfortunately, pateamine is obtained in very small amounts from Mycale hentscheli; thus, it is necessary to synthesise pateamine and novel structural analogues in the laboratory. Previously a separate binding and scaffolding domain of pateamine was proposed, which led to the synthesis of a simplified des-methyl des- amino analogue that reduced the number of synthetic steps compared to pateamine while retaining its biological activity. This was followed by the synthesis of a simplified triazole- containing analogue 9 6 ; unfortunately, this exhibited substantially reduced bioactivity compared to pateamine, and it is therefore necessary to determine if the reduction in bioactivity was due to the replacement of the thiazole ring with a triazole ring, or due to the removal of key methyl groups of pateamine. Thus, the thiazole-containing analogue of 96 is deemed to be an important synthetic target. In this Master’s project a highly simplified side chain-free analogue 130 was synthesised, which laid the groundwork for future synthesis of a thiazole-containing analogue of 96. The synthesis of 130 was achieved through a convergent synthesis with one commercially available and two prepared fragments. Particular attention was paid to the development of an efficient thiazole formation methodology, as well as optimising fragment synthesis and coupling reactions. Determination of the binding of analogue 130 with eIF4A using a competitive bioactivity assay in the presence of pateamine was then undertaken, which showed that either 130 does not bind to eIF4A or that it binds non-covalently and is then displaced by pateamine.