Results for "Antonia Rowlinson"

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Evidence for a TDE origin of the radio transient Cygnus A-2Apr 12 2019In 2015, a radio transient named Cygnus A-2 was discovered in Cygnus A with the Very Large Array. Because of its radio brightness ($\nu F_{\nu} \approx 6 \times 10^{39}$ erg s$^{-1}$), this transient likely represents a secondary black hole in orbit around ... More
Studying the multi-wavelength signals from short GRBsAug 07 2013Since the first host galaxies and afterglows of short GRBs were identified, they have remained very difficult to study: their multiwavelenth afterglows are notoriously faint and host galaxy identification often relies upon minimalising a chance alignment ... More
Can magnetar spin-down power extended emission in some short GRBs?Feb 14 2013Extended emission gamma-ray bursts are a subset of the `short' class of burst which exhibit an early time rebrightening of gamma emission in their light curves. This extended emission arises just after the initial emission spike, and can persist for up ... More
On the Application of Link Analysis Algorithms for Ranking Bipartite GraphsJul 18 2015Recently bipartite graphs have been widely used to represent the relationship two sets of items for information retrieval applications. The Web offers a wide range of data which can be represented by bipartite graphs, such us movies and reviewers in recomender ... More
AARTFAAC Flux Density Calibration and Northern Hemisphere Catalogue at 60 MHzOct 15 2018We present a method for calibrating the flux density scale for images generated by the Amsterdam ASTRON Radio Transient Facility And Analysis Centre (AARTFAAC). AARTFAAC produces a stream of all-sky images at a rate of one second in order to survey the ... More
Identifying transient and variable sources in radio imagesAug 23 2018Mar 18 2019With the arrival of a number of wide-field snapshot image-plane radio transient surveys, there will be a huge influx of images in the coming years making it impossible to manually analyse the datasets. Automated pipelines to process the information stored ... More
Calculating transient rates from surveysNov 18 2016We have developed a method to determine the transient surface density and transient rate for any given survey, using Monte-Carlo simulations. This method allows us to determine the transient rate as a function of both the flux and the duration of the ... More
Constraining coherent low frequency radio flares from compact binary mergersMay 07 2019The presence and detectability of coherent radio emission from compact binary mergers (containing at least one neutron star) remains poorly constrained due to large uncertainties in the models. These compact binary mergers may initially be detected by ... More
The Lorentzian proper vertex amplitude: Classical analysis and quantum derivationFeb 16 2015May 31 2016Spin foam models, an approach to defining the dynamics of loop quantum gravity, make use of the Plebanski formulation of gravity, in which gravity is recovered from a topological field theory via certain constraints called simplicity constraints. However, ... More
A Swan-like TheoremJun 28 2004Aug 17 2004Richard G. Swan proved in 1962 that trinomials x^{8k} + x^m + 1 with 8k > m have an even number of irreducible factors, and so cannot be irreducible. In fact, he found the parity of the number of irreducible factors for any square-free trinomial in F_2[x]. ... More
Permutation properties of Dickson and Chebyshev polynomials and connections to number theoryJul 21 2017Jan 31 2018The $k$th Dickson polynomial of the first kind, $D_k(x) \in {\mathbb Z}[x]$, is determined by the formula: $D_k(u+1/u) = u^k + 1/u^k$, where $k \ge 0$ and $u$ is an indeterminate. These polynomials are closely related to Chebyshev polynomials and have ... More
Elementary background in elliptic curvesAug 22 1997This paper gives additional background in algebraic geometry as an accompaniment to the article, ``Formal Groups, Elliptic Curves, and some Theorems of Couveignes'' [arXiv:math.NT/9708215]. Section 1 discusses the addition law on elliptic curves, and ... More
Bounds on List Decoding Gabidulin CodesMay 02 2012An open question about Gabidulin codes is whether polynomial-time list decoding beyond half the minimum distance is possible or not. In this contribution, we give a lower and an upper bound on the list size, i.e., the number of codewords in a ball around ... More
Formal groups, elliptic curves, and some theorems of CouveignesAug 22 1997The formal group law of an elliptic curve has seen recent applications to computational algebraic geometry in the work of Couveignes to compute the order of an elliptic curve over finite fields of small characteristic. The purpose of this paper is to ... More
Advertising Competitions in Social NetworksAug 09 2016In the present work, we study the advertising competition of several marketing campaigns who need to determine how many resources to allocate to potential customers to advertise their products through direct marketing while taking into account that competing ... More
New Wilson-like theorems arising from Dickson polynomialsJul 21 2017Nov 16 2017Wilson's Theorem states that the product of all nonzero elements of a finite field ${\mathbb F}_q$ is $-1$. In this article, we define some natural subsets $S \subset {\mathbb F}_q^\times$ and find formulas for the product of the elements of $S$, denoted ... More
Time-dependent configuration-interaction-singles calculation of the $5p$-subshell two-photon ionization cross section in xenonDec 21 2016The $5p$ two-photon ionization cross section of xenon in the photon-energy range below the one-photon ionization threshold is calculated within the time-dependent configuration-interaction-singles (TDCIS) method. The TDCIS calculations are compared to ... More
A new identity of Dickson polynomialsOct 19 2016We find a new polynomial identity in characteristic 2: $$\Pi_{w\in F_q^\times} (D_{q+1}(wX)-Y) = X^{q^2-1} + (\sum_{i=1}^{n} Y^{2^{n}-2^i}) X^{q-1} + Y^{q-1},$$ where $q = 2^n$ and $D_k$ is a Dickson polynomial, defined by $D_k(u+u^{-1})=u^k + u^{-k}$. ... More
A Reduced Basis Method for Parabolic Partial Differential Equations with Parameter Functions and Application to Option PricingAug 12 2014We consider the Heston model as an example of a parameterized parabolic partial differential equation. A space-time variational formulation is derived that allows for parameters in the coefficients (for calibration) as well as choosing the initial condition ... More
Linking covariant and canonical LQG II: Spin foam projectorJul 22 2013Nov 26 2013In a seminal paper, Kaminski, Kisielowski an Lewandowski for the first time extended the definition of spin foam models to arbitrary boundary graphs. This is a prerequisite in order to make contact to the canonical formulation of Loop Quantum Gravity ... More
Quantum Maupertuis PrincipleFeb 12 2011According to the Maupertuis principle, the movement of a classical particle in an external potential $V(x)$ can be understood as the movement in a curved space with the metric $g_{\mu\nu}(x)=2M[V(x)-E]\delta_{\mu\nu}$. We show that the principle can be ... More
On the relation between reduced quantisation and quantum reduction for spherical symmetry in loop quantum gravityDec 01 2015Jul 28 2016Building on a recent proposal for a quantum reduction to spherical symmetry from full loop quantum gravity, we investigate the relation between a quantisation of spherically symmetric general relativity and a reduction at the quantum level. To this end, ... More
QSL Squasher: A Fast Quasi-Separatrix Layer Map CalculatorSep 02 2016Quasi-Separatrix Layers (QSLs) are a useful proxy for the locations where current sheets can develop in the solar corona, and give valuable information about the connectivity in complicated magnetic field configurations. However, calculating QSL maps ... More
Stable coherent statesJun 29 2015We analyze the stability under time evolution of complexifier coherent states (CCS) in one-dimensional mechanical systems. A system of coherent states is called stable if it evolves into another coherent state. It turns out that a system can only poses ... More
Bounds on List Decoding of Rank-Metric CodesJan 20 2013Jul 18 2013So far, there is no polynomial-time list decoding algorithm (beyond half the minimum distance) for Gabidulin codes. These codes can be seen as the rank-metric equivalent of Reed--Solomon codes. In this paper, we provide bounds on the list size of rank-metric ... More
Gray-coding through nested setsFeb 09 2015Feb 11 2015We consider the following combinatorial question. Let $$ S_0 \subset S_1 \subset S_2 \subset ...\subset S_m $$ be nested sets, where #$(S_i) = i$. A move consists of altering one of the sets $S_i$, $1 \le i \le m-1$, in a manner so that the nested condition ... More
On existence of Budaghyan-Carlet APN hexanomialsAug 11 2012Aug 16 2012Budaghyan and Carlet constructed a family of almost perfect nonlinear (APN) hexanomials over a field with r^2 elements, and with terms of degrees r+1, s+1, rs+1, rs+r, rs+s, and r+s, where r = 2^m and s = 2^n with GCD(m,n)=1. The construction requires ... More
Green Base Station Placement for Microwave Backhaul LinksJul 18 2017Wireless mobile backhaul networks have been proposed as a substitute in cases in which wired alternatives are not available due to economical or geographical reasons. In this work, we study the location problem of base stations in a given region where ... More
States-conserving density of states for Altshuler-Aronov effect: Heuristic derivationJun 29 2018Altshuler and Aronov (AA) have shown that the electron-electron interaction in a weakly-disordered metal suppresses the single-particle density of states (DOS) in the vicinity of the Fermi level ($E_F$). According to the AA theory the suppressed DOS exhibits ... More
How Tall Can Be the Excursions of a Random Walk on a SpiderFeb 23 2014We consider a simple symmetric random walk on a spider, that is a collection of half lines (we call them legs) joined at the origin. Our main question is the following: if the walker makes $n$ steps how high can he go up on all legs. This problem is discussed ... More
The LOFAR Transients PipelineMar 05 2015Current and future astronomical survey facilities provide a remarkably rich opportunity for transient astronomy, combining unprecedented fields of view with high sensitivity and the ability to access previously unexplored wavelength regimes. This is particularly ... More
Codes for Partially Stuck-at Memory CellsMay 13 2015In this work, we study a new model of defect memory cells, called partially stuck-at memory cells, which is motivated by the behavior of multi-level cells in non-volatile memories such as flash memories and phase change memories. If a cell can store the ... More
Inverting The Generator Of A Generative Adversarial NetworkNov 17 2016Generative adversarial networks (GANs) learn to synthesise new samples from a high-dimensional distribution by passing samples drawn from a latent space through a generative network. When the high-dimensional distribution describes images of a particular ... More
Optimal Ferrers Diagram Rank-Metric CodesMay 08 2014May 25 2014Optimal rank-metric codes in Ferrers diagrams are considered. Such codes consist of matrices having zeros at certain fixed positions and can be used to construct good codes in the projective space. Four techniques and constructions of Ferrers diagram ... More
Defensive Resource Allocation in Social NetworksJul 30 2015In this work, we are interested on the analysis of competing marketing campaigns between an incumbent who dominates the market and a challenger who wants to enter the market. We are interested in (a) the simultaneous decision of how many resources to ... More
Information Spreading on Almost Torus NetworksDec 27 2013Epidemic modeling has been extensively used in the last years in the field of telecommunications and computer networks. We consider the popular Susceptible-Infected-Susceptible spreading model as the metric for information spreading. In this work, we ... More
List Decoding of Locally Repairable CodesJan 12 2018May 08 2018We show that locally repairable codes (LRCs) can be list decoded efficiently beyond the Johnson radius for a large range of parameters by utilizing the local error correction capabilities. The new decoding radius is derived and the asymptotic behavior ... More
QuasiresonanceMay 19 2005The concept of quasiresonance was introduced in connection with inelastic collisions between one atom and a vibro-rotationally excited diatomic molecule. In its original form, the collisions induce {\sl quasiresonant} transfer of energy between the internal ... More
Strategic Resource Allocation for Competitive Influence in Social NetworksFeb 21 2014One of the main objectives of data mining is to help companies determine to which potential customers to market and how many resources to allocate to these potential customers. Most previous works on competitive influence in social networks focus on the ... More
Some Gabidulin Codes cannot be List Decoded Efficiently at any RadiusJan 18 2015Oct 14 2016Gabidulin codes can be seen as the rank-metric equivalent of Reed-Solomon codes. It was recently proven, using subspace polynomials, that Gabidulin codes cannot be list decoded beyond the so-called Johnson radius. In another result, cyclic subspace codes ... More
Sub-Quadratic Decoding of Gabidulin CodesJan 23 2016Apr 13 2016This paper shows how to decode errors and erasures with Gabidulin codes in sub-quadratic time in the code length, improving previous algorithms which had at least quadratic complexity. The complexity reduction is achieved by accelerating operations on ... More
Adversarial Training For Sketch RetrievalJul 10 2016Aug 23 2016Generative Adversarial Networks (GAN) are able to learn excellent representations for unlabelled data which can be applied to image generation and scene classification. Representations learned by GANs have not yet been applied to retrieval. In this paper, ... More
Denoising Adversarial AutoencodersMar 03 2017Jan 04 2018Unsupervised learning is of growing interest because it unlocks the potential held in vast amounts of unlabelled data to learn useful representations for inference. Autoencoders, a form of generative model, may be trained by learning to reconstruct unlabelled ... More
A classification of locally homogeneous affine connections on compact surfacesApr 21 2014We classify the affine connections on compact orientable surfaces for which the pseudogroup of local isometries acts transitively. We prove that such a connection is either torsion-free and flat, the Levi-Civita connection of a Riemannian metric of constant ... More
Fast Operations on Linearized Polynomials and their Applications in Coding TheoryDec 21 2015This paper considers fast algorithms for operations on linearized polynomials. Among these results are fast algorithms for division of linearized polynomials, $q$-transform, multi-point evaluation, computing minimal subspace polynomials and interpolation. ... More
Vector Network Coding Based on Subspace Codes Outperforms Scalar Linear Network CodingDec 20 2015May 15 2016This paper considers vector network coding solutions based on rank-metric codes and subspace codes. The main result of this paper is that vector solutions can significantly reduce the required field size compared to the optimal scalar linear solution ... More
Modelling supernova line profile asymmetries to determine ejecta dust masses: SN 1987A from days 714 to 3604Sep 02 2015Nov 27 2015The late time optical and near-IR line profiles of many core-collapse supernovae exhibit a red-blue asymmetry as a result of greater extinction by internal dust of radiation emitted from the receding parts of the supernova ejecta. We present here a new ... More
Task Specific Adversarial Cost FunctionSep 27 2016The cost function used to train a generative model should fit the purpose of the model. If the model is intended for tasks such as generating perceptually correct samples, it is beneficial to maximise the likelihood of a sample drawn from the model, Q, ... More
List and Unique Error-Erasure Decoding of Interleaved Gabidulin Codes with Interpolation TechniquesApr 24 2014A new interpolation-based decoding principle for interleaved Gabidulin codes is presented. The approach consists of two steps: First, a multi-variate linearized polynomial is constructed which interpolates the coefficients of the received word and second, ... More
Vector Network Coding Based on Subspace Codes Outperforms Scalar Linear Network CodingApr 12 2016May 13 2016This paper considers vector network coding based on rank-metric codes and subspace codes. Our main result is that vector network coding can significantly reduce the required field size compared to scalar linear network coding in the same multicast network. ... More
Efficient Interpolation-Based Decoding of Interleaved Subspace and Gabidulin CodesAug 06 2014An interpolation-based decoding scheme for interleaved subspace codes is presented. The scheme can be used as a (not necessarily polynomial-time) list decoder as well as a probabilistic unique decoder. Both interpretations allow to decode interleaved ... More
Fast Operations on Linearized Polynomials and their Applications in Coding TheoryDec 21 2015Jul 11 2017This paper considers fast algorithms for operations on linearized polynomials. We propose a new multiplication algorithm for skew polynomials (a generalization of linearized polynomials) which has sub-quadratic complexity in the polynomial degree $s$, ... More
Inverting The Generator Of A Generative Adversarial Network (II)Feb 15 2018Generative adversarial networks (GANs) learn a deep generative model that is able to synthesise novel, high-dimensional data samples. New data samples are synthesised by passing latent samples, drawn from a chosen prior distribution, through the generative ... More
The AARTFAAC All Sky Monitor: System Design and ImplementationSep 14 2016The Amsterdam-ASTRON Radio Transients Facility And Analysis Center (AARTFAAC) all sky monitor is a sensitive, real time transient detector based on the Low Frequency Array (LOFAR). It generates images of the low frequency radio sky with spatial resolution ... More
Efficient Decoding of Partial Unit Memory Codes of Arbitrary RateFeb 08 2012Partial Unit Memory (PUM) codes are a special class of convolutional codes, which are often constructed by means of block codes. Decoding of PUM codes may take advantage of existing decoders for the block code. The Dettmar--Sorger algorithm is an efficient ... More
Wave refraction in left-handed materialsOct 24 2008We examine the response of a plane wave incident on a flat surface of a medium characterized by simultaneously negative electric and magnetic susceptibilities by solving Maxwell's equations explicitly and without making any assumptions on the way. In ... More
Decoding Cyclic Codes up to a New Bound on the Minimum DistanceMay 10 2011Mar 12 2012A new lower bound on the minimum distance of q-ary cyclic codes is proposed. This bound improves upon the Bose-Chaudhuri-Hocquenghem (BCH) bound and, for some codes, upon the Hartmann-Tzeng (HT) bound. Several Boston bounds are special cases of our bound. ... More
The spectral energy distribution of protoplanetary diss around Massive Young Stellar ObjectsOct 19 2012We investigate the effect of ionising radiation from Massive Young Stellar Objects impinging on their emerging spectral energy distribution. By means of detailed radiative transfer calculations including both the gaseous and dust phase of their surrounding ... More
Decoding High-Order Interleaved Rank-Metric CodesApr 18 2019This paper presents an algorithm for decoding homogeneous interleaved codes of high interleaving order in the rank metric. The new decoder is an adaption of the Hamming-metric decoder by Metzner and Kapturowski (1990) and guarantees to correct all rank ... More
Unparticle Casimir effectNov 27 2013Jul 17 2017In this paper we present the un-Casimir effect, namely the study of the Casimir energy in the presence of an unparticle component in addition to the electromagnetic field contribution. The distinctive feature of the un-Casimir effect is a fractalization ... More
Random Spherical TrianglesSep 27 2010Dec 21 2015Let Delta be a random spherical triangle (meaning that vertices are independent and uniform on the unit sphere). A closed-form expression for the area density of Delta has been known since 1867; a complicated integral expression for the perimeter density ... More
On the universality of thermodynamics and $η/s$ ratio for the charged Lovelock black branesFeb 17 2016Feb 24 2016We investigate general features of charged Lovelock black branes by giving a detailed description of geometrical, thermodynamic and holographic properties of charged Gauss-Bonnet (GB) black branes in five dimensions. We show that when expressed in terms ... More
Locality in Crisscross Error CorrectionJun 19 2018Sep 04 2018The cover metric is suitable for describing the resilience against correlated errors in arrays, in particular crisscross errors, which makes it interesting for applications such as distributed data storage (DDS). In this work, we consider codes designed ... More
Improving Sampling from Generative Autoencoders with Markov ChainsOct 28 2016Jan 12 2017We focus on generative autoencoders, such as variational or adversarial autoencoders, which jointly learn a generative model alongside an inference model. Generative autoencoders are those which are trained to softly enforce a prior on the latent distribution ... More
LatentPoison - Adversarial Attacks On The Latent SpaceNov 08 2017Robustness and security of machine learning (ML) systems are intertwined, wherein a non-robust ML system (classifiers, regressors, etc.) can be subject to attacks using a wide variety of exploits. With the advent of scalable deep learning methodologies, ... More
Local Commutators and Deformations in Conformal Chiral Quantum Field TheoriesMay 15 2011We study the general form of M"obius covariant local commutation relations in conformal chiral quantum field theories and show that they are intrinsically determined up to structure constants, which are subject to an infinite system of constraints. The ... More
Adiabaticity and diabaticity in strong-field ionizationApr 22 2013If the photon energy is much less than the electron binding energy, ionization of an atom by a strong optical field is often described in terms of electron tunneling through the potential barrier resulting from the superposition of the atomic potential ... More
The Lorentzian proper vertex amplitude: AsymptoticsMay 25 2015May 31 2016In previous work, the Lorentzian proper vertex amplitude for a spin-foam model of quantum gravity was derived. In the present work, the asymptotics of this amplitude are studied in the semi-classical limit. The starting point of the analysis is an expression ... More
Convolutional Codes in Rank Metric with Application to Random Network CodingApr 29 2014Jan 19 2015Random network coding recently attracts attention as a technique to disseminate information in a network. This paper considers a non-coherent multi-shot network, where the unknown and time-variant network is used several times. In order to create dependencies ... More
Finite size effects on liquid-solid phase coexistence and the estimation of crystal nucleation barriersJan 07 2015A fluid in equilibrium in a finite volume $V$ with particle number $N$ at a density $\rho = N/V$ exceeding the onset density $\rho_f $ of freezing may exhibit phase coexistence between a crystalline nucleus and surrounding fluid. Using a method suitable ... More
Matrix Elements of Lorentzian Hamiltonian Constraint in LQGJun 04 2013Jul 18 2013The Hamiltonian constraint is the key element of the canonical formulation of LQG coding its dynamics. In Ashtekar-Barbero variables it naturally splits into the so called Euclidean and Lorentzian parts. However, due to the high complexity of this operator, ... More
Linking covariant and canonical LQG: new solutions to the Euclidean Scalar ConstraintSep 06 2011It is often emphasized that spin-foam models could realize a projection on the physical Hilbert space of canonical Loop Quantum Gravity (LQG). As a first test we analyze the one-vertex expansion of a simple Euclidean spin-foam. We find that for fixed ... More
Bounds on Codes Correcting Tandem and Palindromic DuplicationsJun 30 2017Jan 16 2018In this work, we derive upper bounds on the cardinality of tandem duplication and palindromic deletion correcting codes by deriving the generalized sphere packing bound for these error types. We first prove that an upper bound for tandem deletions is ... More
Escape of photons from two fixed extreme Reissner-Nordström black holesJan 09 2007Nov 20 2008We study the scattering of light (null geodesics) by two fixed extreme Reissner-Nordstr\"om black holes, in which the gravitational attraction of their masses is exactly balanced with the electrostatic repulsion of their charges, allowing a static spacetime. ... More
Twisted Gabidulin Codes in the GPT CryptosystemJun 26 2018Aug 14 2018In this paper, we investigate twisted Gabidulin codes in the GPT code-based public-key cryptosystem. We show that Overbeck's attack is not feasible for a subfamily of twisted Gabidulin codes. The resulting key sizes are significantly lower than in the ... More
Duplication-Correcting CodesDec 24 2017In this work, we propose constructions that correct duplications of multiple consecutive symbols. These errors are known as tandem duplications, where a sequence of symbols is repeated; respectively as palindromic duplications, where a sequence is repeated ... More
Improving Sampling from Generative Autoencoders with Markov ChainsOct 28 2016We focus on generative autoencoders, such as variational or adversarial autoencoders, which jointly learn a generative model alongside an inference model. We define generative autoencoders as autoencoders which are trained to softly enforce a prior on ... More
Network MIMO with Linear Zero-Forcing Beamforming: Large System Analysis, Impact of Channel Estimation and Reduced-Complexity SchedulingDec 15 2010Sep 12 2011We consider the downlink of a multi-cell system with multi-antenna base stations and single-antenna user terminals, arbitrary base station cooperation clusters, distance-dependent propagation pathloss, and general "fairness" requirements. Base stations ... More
A Basis for all Solutions of the Key Equation for Gabidulin CodesJun 09 2010We present and prove the correctness of an efficient algorithm that provides a basis for all solutions of a key equation in order to decode Gabidulin (G-) codes up to a given radius tau. This algorithm is based on a symbolic equivalent of the Euclidean ... More
Crystal nuclei in melts: A Monte Carlo simulation of a model for attractive colloidsApr 02 2015May 06 2015As a model for a suspension of hard-sphere like colloidal particles where small nonadsorbing dissolved polymers create a depletion attraction, we introduce an effective colloid-colloid potential closely related to the Asakura-Oosawa model but that does ... More
Constraints on the pMSSM from searches for squarks and gluinos by ATLASFeb 28 2012We study the impact of the jets and missing transverse momentum SUSY analyses of the ATLAS experiment on the phenomenological MSSM (pMSSM). We investigate sets of SUSY models with a flat and logarithmic prior in the SUSY mass scale and a mass range up ... More
Un-Casimir effectNov 27 2013Mar 04 2014In this paper we present the un-Casimir effect, namely the study of the Casimir energy related to the presence of an un-particle component in addition to the electromagnetic field contribution. We derive this result by considering modifications of the ... More
Spin foam propagator: A new perspective to include a cosmological constantNov 30 2017May 01 2018In recent years, the calculation of the first non-vanishing order of the metric 2-point function or graviton propagator in a semiclassical limit has evolved as a standard test for the credibility of a proposed spin foam model. The existing results of ... More
Possible persistent current in a ring made of the perfect crystalline insulatorDec 06 2007A mesoscopic conducting ring pierced by magnetic flux is known to support the persistent electron current. Here we propose possibility of the persistent current in the ring made of the perfect crystalline insulator. We consider a ring-shaped lattice of ... More
On a Rank-Metric Code-Based Cryptosystem with Small Key SizeDec 12 2018A repair of the Faure-Loidreau (FL) public-key code-based cryptosystem is proposed. The FL cryptosystem is based on the hardness of list decoding Gabidulin codes which are special rank-metric codes. We prove that the recent structural attack on the system ... More
Geometric model of black hole quantum $N$-portrait, extradimensions and thermodynamicsApr 12 2016May 19 2016Recently a short scale modified black hole metric, known as holographic metric, has been proposed in order to capture the self-complete character of gravity. In this paper we show that such a metric can reproduce some geometric features expected from ... More
On Error Decoding of Locally Repairable and Partial MDS CodesApr 11 2019We consider error decoding of locally repairable codes (LRC) and partial MDS (PMDS) codes through interleaved decoding. For a specific class of LRCs we investigate the success probability of interleaved decoding. For PMDS codes we show that there is a ... More
On denoising autoencoders trained to minimise binary cross-entropyAug 28 2017Oct 09 2017Denoising autoencoders (DAEs) are powerful deep learning models used for feature extraction, data generation and network pre-training. DAEs consist of an encoder and decoder which may be trained simultaneously to minimise a loss (function) between an ... More
About the distance between random walkers on some graphsApr 27 2016Jul 26 2016We consider two or more simple symmetric walks on some graphs, e.g. the real line, the plane or the two dimensional comb lattice, and investigate the properties of the distance among the walkers.
Improving Sampling from Generative Autoencoders with Markov ChainsOct 28 2016Nov 07 2016We focus on generative autoencoders, such as variational or adversarial autoencoders, which jointly learn a generative model alongside an inference model. Generative autoencoders are those which are trained to softly enforce a prior on the latent distribution ... More
Relaxation Phenomena in a System of Two Harmonic OscillatorsMay 21 2007Mar 07 2008We study the process by which quantum correlations are created when an interaction Hamiltonian is repeatedly applied to a system of two harmonic oscillators for some characteristic time interval. We show that, for the case where the oscillator frequencies ... More
Quantum correlations and energy currents across finite harmonic chainsMar 31 2015We present a study that addresses both the stationary properties of the energy current and quantum correlations in a three-mode chain subjected to Ohmic and super-Ohmic dissipa- tions. An extensive numerical analysis shows that the mean value and the ... More
Emergent 4-dimensional linearized gravity from spin foam modelDec 05 2018Spin Foam Models (SFMs) are covariant formulations of Loop Quantum Gravity (LQG) in 4 dimensions. This work studies the perturbations of SFMs on a flat background. It demonstrates for the first time that smooth curved spacetime geometries satisfying Einstein ... More
Wave-packet propagation based calculation of above-threshold ionization in the x-ray regimeFeb 19 2015We investigate the multi-photon process of above-threshold ionization for the light elements hydrogen, carbon, nitrogen and oxygen in the hard x-ray regime. Numerical challenges are discussed and by comparing Hartree-Fock-Slater calculations to configuration-interaction-singles ... More
Repairing the Faure-Loidreau Public-Key CryptosystemJan 11 2018May 07 2018A repair of the Faure-Loidreau (FL) public-key code-based cryptosystem is proposed. The FL cryptosystem is based on the hardness of list decoding Gabidulin codes which are special rank-metric codes. We prove that the recent structural attack on the system ... More
Interleaving Loidreau's Rank-Metric CryptosystemJan 29 2019We propose and analyze an interleaved variant of Loidreau's rank-metric cryptosystem based on rank multipliers. It can be seen as the rank-metric analog of a recent proposal based on interleaved Goppa codes by Elleuch et al.. We analyze and adapt several ... More
Denoising Adversarial Autoencoders: Classifying Skin Lesions Using Limited Labelled Training DataJan 02 2018We propose a novel deep learning model for classifying medical images in the setting where there is a large amount of unlabelled medical data available, but labelled data is in limited supply. We consider the specific case of classifying skin lesions ... More
Improved Decoding and Error Floor Analysis of Staircase CodesApr 06 2017Dec 03 2018Staircase codes play an important role as error-correcting codes in optical communications. In this paper, a low-complexity method for resolving stall patterns when decoding staircase codes is described. Stall patterns are the dominating contributor to ... More
Dust masses for SN 1980K, SN1993J and Cassiopeia A from red-blue emission line asymmetriesNov 15 2016We present Monte Carlo line transfer models that investigate the effects of dust on the very late time emission line spectra of the core collapse supernovae SN 1980K and SN 1993J and the young core collapse supernova remnant Cassiopeia A. Their blue-shifted ... More
Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observationsJan 12 2016Geomagnetically-aligned density structures with a range of sizes exist in the near-Earth plasma environment, including 10-100 km-wide VLF/HF wave-ducting structures. Their small diameters and modest density enhancements make them difficult to observe, ... More