Results for "Dino Novko"

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Broken adiabaticity induced by Lifshitz transition in MoS$_2$ and WS$_2$ single layersJul 10 2019The breakdown of the adiabatic Born-Oppenheimer approximation is striking dynamical phenomenon, however, it occurs only in a handful of layered materials. Here I show that adiabaticity breaks down in doped single-layer transition metal dichalcogenides ... More
Optical absorption and conductivity in quasi-two-dimensional crystals from first principles: Application to grapheneDec 12 2015This paper gives a theoretical formulation of the electromagnetic response of the quasi-two-dimensional (Q2D) crystals suitable for investigation of optical activity and polariton modes. The response to external electromagnetic field is described by current-current ... More
Nonadiabatic coupling effects in MgB$_2$ reexaminedJun 08 2018Jul 23 2018The unusual Raman spectrum of MgB$_2$ and its formidable temperature dependence are successfully reproduced by means of a parameter-free \emph{ab initio} nonadiabatic theory that accounts for the electron-hole pair scattering mechanisms with the system ... More
Dopant-induced plasmon decay in grapheneAug 15 2017Oct 05 2017Chemically doped graphene could support plasmon excitations up to telecommunication or even visible frequencies. Apart from that, the presence of dopant may influence electron scattering mechanisms in graphene and thus impact the plasmon decay rate. Here ... More
Metal surface induces strong acoustic plasmons in chemically doped grapheneJul 05 2019Recent theoretical considerations have demonstrated that freestanding graphene doped with alkali metals (AC x ) supports strong Dirac and weak acoustic plasmons. Here we show that when AC x is deposited on a metallic surface, the intense Coulomb screening ... More
Electron-mediated phonon-phonon coupling drives the vibrational relaxation of CO on Cu(100)Mar 16 2018We bring forth a consistent theory for the electron-mediated vibrational intermode coupling that clarifies the microscopic mechanism behind the vibrational relaxation of adsorbates on metal surfaces. Our analysis points out the inability of state-of-the-art ... More
Phonon-assisted damping of plasmons in three- and two-dimensional metalsMay 07 2018We investigate the effects of crystal lattice vibrations on the dispersion of plasmons. The loss function of the homogeneous electron gas (HEG) in two and three dimensions is evaluated numerically in presence of electronic coupling to an optical phonon ... More
Changing character of electronic transitions in graphene: From single particle excitations to plasmonsDec 15 2015In this paper we clarify the nature of $\pi$ and $\pi+\sigma$ electron excitations in pristine graphene. We clearly demonstrate the continuous transition from single particle to collective character of such excitations and how screening modifies their ... More
A practical algorithm to compute the geometric Picard lattice of K3 surfaces of degree $2$Aug 01 2018Oct 08 2018Let $k$ be either a number a field or a function field over $\mathbb{Q}$ with finitely many variables. We present a practical algorithm to compute the geometric Picard lattice of a K3 surface over $k$ of degree $2$, i.e., a double cover of the projective ... More
On functors enumerating structuresJun 19 2017Aug 10 2017We study a new notion of reduction between structures called enumerable functors related to the recently investigated notion of computable functors. Our main result shows that enumerable functors and effective interpretability with the equivalence relation ... More
Scaling between structural relaxation and caged dynamics in Ca_{0.4}K_0.6(NO_{3})_{1.4} and glycerol: free volume, time scales and implications for the pressure-energy correlationsJan 14 2011The scaling of the slow structural relaxation with the fast caged dynamics is evidenced in the molten salt Ca_{0.4}K_{0.6}(NO_{3}$)_{1.4} (CKN) over about thirteen decades of the structural relaxation time. Glycerol caling was analyzed in detail. In glycerol, ... More
The complexity of Scott sentences of scattered linear ordersOct 26 2018Feb 15 2019Given a countable scattered linear order $L$ of Hausdorff rank $\alpha < \omega_1$ we show that it has a $d\text{-}\Sigma_{2\alpha+1}$ Scott sentence. Ash calculated the back and forth relations for all countable well-orders. From this result we obtain ... More
Elastic modulus and yield strength of semicrystalline polymers with bond disorder are higher than in atomic crystalsNov 16 2018We perform thorough molecular-dynamics simulations to compare elasticity and yielding of atomic crystals and model semicrystalline polymers, the latter characterized by very similar positional ordering with respect to atomic crystals and considerable ... More
Effect of non-specific interactions on formation and stability of specific complexesFeb 04 2016We introduce a simple model to describe the interplay between specific and non-specific interactions. We study the influence of various physical factors on the static and dynamic properties of the specific interactions of our model and show that contrary ... More
Linear feature detection algorithm for astronomical surveys - I. Algorithm descriptionDec 14 2016Jun 18 2017Computer vision algorithms are powerful tools in astronomical image analyses, especially when automation of object detection and extraction is required. Modern object detection algorithms in astronomy are oriented towards detection of stars and galaxies, ... More
Chemically Active Nanodroplets in a Multi-Component FluidApr 29 2019We introduce a model of chemically active particles of a multi-component fluid that can change their interactions with other particles depending on their state. Since such switching of interactions can only be maintained by the input of chemical energy, ... More
Reduction of points in the group of componentsMar 24 1999Let $K$ be a complete discrete valuation field with ring of integers $\co_K$. Let $X/K$ be a proper smooth curve and let $A/K$ denote its jacobian. Let $P$ and $Q$ belong to $X(K)$. The divisor $P - Q$ defines a $K$-rational point of $A/K$. In this article, ... More
Arithmetical properties of Laplacians of graphsMar 18 1999Let $M \in M_n (\mathbb Z)$ denote any matrix. Thinking of $M$ as a linear map $M:{\mathbb Z}^n \to {\mathbb Z}^n$, we denote by ${\Image}(M)$ the $\mathbb Z$-span of the column vectors of $M$. Let $e_1, ..., e_n,$ denote the standard basis of ${\mathbb ... More
Generalizing input-driven languages: theoretical and practical benefitsMay 02 2017Regular languages (RL) are the simplest family in Chomsky's hierarchy. Thanks to their simplicity they enjoy various nice algebraic and logic properties that have been successfully exploited in many application fields. Practically all of their related ... More
New Points on CurvesNov 09 2017Let K be a field and let L/K be a finite extension. Let X/K be a scheme of finite type. A point of X(L) is said to be new if it does not belong to the union of X(F), when F runs over all proper subextensions of L. Fix now an integer g>0 and a finite separable ... More
The cool potential of gluonsNov 09 2015We put forward the idea that the quark-gluon plasma might exist way below the usual confinement temperature $T_c$. Our argument rests on the possibility that the plasma produced in heavy-ion collisions could reach a transient quasi-equilibrium with `over-occupied' ... More
Note on Noisy Group Testing: Asymptotic Bounds and Belief Propagation ReconstructionOct 12 2010An information theoretic perspective on group testing problems has recently been proposed by Atia and Saligrama, in order to characterise the optimal number of tests. Their results hold in the noiseless case, where only false positives occur, and where ... More
Dynamics of Active Rouse ChainsAug 21 2016We consider how active forces modeled as non-thermal random noise affect the average dynamical properties of a Rouse polymer. As the power spectrum of the noise is not known we keep the analytical treatment as generic as possible and then present results ... More
Scalable Learning in Reproducing Kernel Krein SpacesSep 06 2018May 30 2019We provide the first mathematically complete derivation of the Nystr\"om method for low-rank approximation of indefinite kernels and propose an efficient method for finding an approximate eigendecomposition of such kernel matrices. Building on this result, ... More
Fingerprints of Ultrafast Hot Phonon Dynamics in MgB$_2$Apr 05 2019The zone-center $E_{2g}$ modes play a crucial role in MgB$_2$, controlling the scattering mechanisms in the normal state as well the superconducting pairing. In this Letter, we demonstrate via first-principles quantum-field theory calculations that, due ... More
Detecting Data Races on OpenCL Kernels with Symbolic ExecutionAug 14 2013We present an automatic analysis technique for checking data races on OpenCL kernels. Our method defines symbolic execution techniques based on separation logic with suitable abstractions to automatically detect non-benign racy behaviours on kernel
Boson Peak decouples from elasticity in glasses with low connectivityOct 24 2018We perform molecular-dynamics simulations of the vibrational and the elasto-plastic properties of polymeric glasses and crystals and corresponding atomic systems. We evidence that the elastic scaling of the density of states in the low-frequency boson ... More
Moderately ramified actions in positive characteristicApr 17 2019In characteristic two and dimension two, wild Z/2Z-actions on k[[u,v]] ramified precisely at the origin were classified by Artin, who showed in particular that they induce hypersurface singularities. We introduce in this article a new class of wild quotient ... More
Viscous Flow and Jump Dynamics in Molecular Supercooled Liquids: II RotationsDec 10 1999The rotational dynamics of a supercooled molecular liquid is investigated by a molecular-dynamics numerical study. We detect rotational jumps with a waiting-time distribution which is well fitted by a truncated power law. At lower temperatures the rotational ... More
Bhabha Scattering and a special pencil of K3 surfacesSep 13 2018Oct 24 2018We study a pencil of K3 surfaces that appeared in the $2$-loop diagrams in Bhabha scattering. By analysing in detail the Picard lattice of the general and special members of the pencil, we identify the pencil with the celebrated Ap\'ery--Fermi pencil, ... More
Unirationality of del Pezzo surfaces of degree two over finite fieldsMay 05 2015We prove that every del Pezzo surface of degree two over a finite field is unirational, building on the work of Manin and an extension by Salgado, Testa, and V\'arilly-Alvarado, who had proved this for all but three surfaces. Over general fields of characteristic ... More
Viscous Flow and Jump Dynamics in Molecular Supercooled Liquids: I TranslationsDec 10 1999We study the transport and the relaxation properties of a molecular supercooled liquid by molecular-dynamics numerical simulations. The focus is on the translational motion. Jump motion is detected. At lower temperature the Stokes-Einstein law breaks ... More
Thue equations and the method of Coleman-ChabautyMay 18 2000In this paper, we prove that a Thue equation F(x,y) = h, where h is an integer and F is a polynomial of degree n with integer coefficients and without repeated roots, has at most 2n^3 - 2n - 3 solutions provided that the Mordell-Weil rank of the Jacboian ... More
Unirationality of del Pezzo surfaces of degree two over finite fields (extended version)Aug 01 2014May 05 2015We prove that every del Pezzo surface of degree two over a finite field is unirational, building on the work of Manin and an extension by Salgado, Testa, and V\'arilly-Alvarado, who had proved this for all but three surfaces. Over general fields, we state ... More
Hamiltonian Variational Auto-EncoderMay 29 2018Nov 23 2018Variational Auto-Encoders (VAEs) have become very popular techniques to perform inference and learning in latent variable models as they allow us to leverage the rich representational power of neural networks to obtain flexible approximations of the posterior ... More
Hyperspectral Image Classification with Support Vector Machines on Kernel Distribution EmbeddingsMay 30 2016We propose a novel approach for pixel classification in hyperspectral images, leveraging on both the spatial and spectral information in the data. The introduced method relies on a recently proposed framework for learning on distributions -- by representing ... More
Effective two-dimensional model for granular matter with phase separationApr 10 2018Granular systems confined in vertically vibrated shallow horizontal boxes (quasi two-dimensional geometry) present a liquid to solid phase transition when the frequency of the periodic forcing is increased. An effective model, where grains move and collide ... More
A Kernel Test for Three-Variable InteractionsJun 10 2013We introduce kernel nonparametric tests for Lancaster three-variable interaction and for total independence, using embeddings of signed measures into a reproducing kernel Hilbert space. The resulting test statistics are straightforward to compute, and ... More
Nonparametric Independence Testing for Right-Censored Data using Optimal TransportJun 10 2019We propose a nonparametric test of independence, termed OPT-HSIC, between a covariate and a right-censored lifetime. Because the presence of censoring creates a challenge in applying the standard permutation-based testing approaches, we use optimal transport ... More
Poisson intensity estimation with reproducing kernelsOct 27 2016Despite the fundamental nature of the inhomogeneous Poisson process in the theory and application of stochastic processes, and its attractive generalizations (e.g.~Cox process), few tractable nonparametric modeling approaches of intensity functions exist, ... More
Measuring the complexity of reductions between equivalence relationsJun 27 2018Computable reducibility is a well-established notion that allows to compare the complexity of various equivalence relations over the natural numbers. We generalize computable reducibility by introducing degree spectra of reducibility and bi-reducibility. ... More
Shear viscosity of a model for confined granular mediaSep 09 2014Dec 06 2014The shear viscosity in the dilute regime of a model for confined granular matter is studied by simulations and kinetic theory. The model consists on projecting into two dimensions the motion of vibrofluidized granular matter in shallow boxes by modifying ... More
Hydrodynamic modes in a confined granular fluidJan 17 2013Feb 14 2013Confined granular fluids, placed in a shallow box that is vibrated vertically, can achieve homogeneous stationary states thanks to energy injection mechanisms that take place throughout the system. These states can be stable even at high densities and ... More
Temporal Logic and Model Checking for Operator Precedence LanguagesSep 10 2018In the last decades much research effort has been devoted to extending the success of model checking from the traditional field of finite state machines and various versions of temporal logics to suitable subclasses of context-free languages and appropriate ... More
The index of an algebraic varietySep 13 2012Let K be the field of fractions of a Henselian discrete valuation ring O_K. Let X_K/K be a smooth proper geometrically connected scheme admitting a regular model X/O_K. We show that the index \delta(X_K/K) of X_K/K can be explicitly computed using data ... More
Classes of Terminating Logic ProgramsJun 25 2001Jul 22 2002Termination of logic programs depends critically on the selection rule, i.e. the rule that determines which atom is selected in each resolution step. In this article, we classify programs (and queries) according to the selection rules for which they terminate. ... More
Molecular layers in thin supported films exhibit the same scaling as the bulk between slow relaxation and vibrational dynamicsOct 24 2018We perform molecular dynamics simulations of a supported molecular thin film. By varying thickness and temperature, we observe anisotropic mobility as well as strong gradients of both the vibrational motion and the structural relaxation through film layers ... More
Inertially-induced secondary flow in microchannelsOct 18 2011We report a novel technique to passively create strong secondary flows at moderate to high flow rates in microchannels, accurately control them and finally, due to their deterministic nature, program them into microfluidic platforms. Based on the flow ... More
Parzen Filters for Spectral Decomposition of SignalsJun 23 2019We propose a novel family of band-pass filters for efficient spectral decomposition of signals. Previous work has already established the effectiveness of representations based on static band-pass filtering of speech signals (e.g., mel-frequency cepstral ... More
Thermal convection in fluidized granular systemsFeb 28 2000Thermal convection is observed in molecular dynamic simulation of a fluidized granular system of nearly elastic hard disks moving under gravity, inside a rectangular box. Boundaries introduce no shearing or time dependence, but the energy injection comes ... More
Modeling a vehicular traffic network. Part IOct 26 2016Oct 24 2017We propose three models for the traffic of vehicles within a network formed by sites (cities, car-rental agencies, parking lots, etc.) and connected by two-way arteries (roads, highways), that allow forecasting the vehicular flux in a sequence of $n$ ... More
Eta-photoproduction in a gauge-invariant chiral unitary frameworkAug 24 2011Sep 26 2011We analyse photoproduction of eta mesons off the proton in a gauge-invariant chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the leading order chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. ... More
Precedence Automata and LanguagesDec 10 2010Nov 30 2011Operator precedence grammars define a classical Boolean and deterministic context-free family (called Floyd languages or FLs). FLs have been shown to strictly include the well-known visibly pushdown languages, and enjoy the same nice closure properties. ... More
Bi-embeddability spectra and bases of spectraAug 16 2018We study degree spectra of structures relative to the bi-embeddability relation. The bi-embeddability spectrum of a structure is the family of Turing degrees of structures bi-embeddable with it. We introduce the notions of bi-embeddable triviality and ... More
Unbiased Bayes for Big Data: Paths of Partial PosteriorsJan 14 2015Feb 09 2015A key quantity of interest in Bayesian inference are expectations of functions with respect to a posterior distribution. Markov Chain Monte Carlo is a fundamental tool to consistently compute these expectations via averaging samples drawn from an approximate ... More
Bond disorder, frustration and polymorphism in the spontaneous crystallization of a polymer meltNov 16 2018The isothermal, isobaric spontaneous crystallization of a supercooled polymer melt is investigated by MD simulation of an ensemble of fully-flexible linear chains. Frustration is introduced via two incommensurate length scales set by the bond length and ... More
Extended event driven molecular dynamics for simulating dense granular matterDec 21 2010A new numerical method is presented to efficiently simulate the inelastic hard sphere (IHS) model for granular media, when fluid and frozen regions coexist in the presence of gravity. The IHS model is extended by allowing particles to change their dynamics ... More
Structure and equation of state of interaction site models for disc-shaped lamellar colloidsDec 17 2004We apply RISM (Reference Interaction Site Model) and PRISM (polymer-RISM) theories to calculate the site-site pair structure and the osmotic equation of state of suspensions of circular or hexagonal platelets (lamellar colloids) over a range of ratios ... More
K2-ABC: Approximate Bayesian Computation with Kernel EmbeddingsFeb 09 2015Dec 26 2015Complicated generative models often result in a situation where computing the likelihood of observed data is intractable, while simulating from the conditional density given a parameter value is relatively easy. Approximate Bayesian Computation (ABC) ... More
Corrigendum to Néron models, Lie algebras, and reduction of curves of genus one [LLR1] and The Brauer group of a surface [LLR2]Apr 30 2018Jun 09 2018Let X be a proper smooth and connected surface over a finite field. We proved in [LLR2] that the order of the Brauer group Br(X) of X is a perfect square if it is finite. Our proof is based in part on a result of Gordon [Gor], which we used in [LLR1] ... More
Logic Characterization of Floyd LanguagesApr 20 2012Floyd languages (FL), alias Operator Precedence Languages, have recently received renewed attention thanks to their closure properties and local parsability which allow one to apply automatic verification techniques (e.g. model checking) and parallel ... More
A Classification for Community Discovery Methods in Complex NetworksJun 15 2012In the last few years many real-world networks have been found to show a so-called community structure organization. Much effort has been devoted in the literature to develop methods and algorithms that can efficiently highlight this hidden structure ... More
Approximate Message Passing under Finite Alphabet ConstraintsJan 24 2012In this paper we consider Basis Pursuit De-Noising (BPDN) problems in which the sparse original signal is drawn from a finite alphabet. To solve this problem we propose an iterative message passing algorithm, which capitalises not only on the sparsity ... More
DR-ABC: Approximate Bayesian Computation with Kernel-Based Distribution RegressionFeb 15 2016Performing exact posterior inference in complex generative models is often difficult or impossible due to an expensive to evaluate or intractable likelihood function. Approximate Bayesian computation (ABC) is an inference framework that constructs an ... More
Intercities traffic flow: linear and nonlinear modelsOct 26 2016We simulate the traffic of vehicles circulating within a network formed by sites (cities, car-rental agencies, etc.) connected by two-way roads or highways, to which we shall refer generically as intercity traffic. Our aim is to forecast the flux of the ... More
Bi-embeddability spectra and bases of spectraAug 16 2018Apr 02 2019We study degree spectra of structures with respect to the bi-embeddability relation. The bi-embeddability spectrum of a structure is the family of Turing degrees of its bi-embeddable copies. To facilitate our study we introduce the notions of bi-embeddable ... More
A Wild Bootstrap for Degenerate Kernel TestsAug 23 2014Sep 27 2016A wild bootstrap method for nonparametric hypothesis tests based on kernel distribution embeddings is proposed. This bootstrap method is used to construct provably consistent tests that apply to random processes, for which the naive permutation-based ... More
Effect of the vibration profile on shallow granular systemsMar 02 2016We describe the collective behavior of a system of many inelastic spherical particles inside a box which is being periodically vibrated. The box is shallow, with large horizontal dimensions, while the height is less than two particle diameters. The vibrations ... More
Hypersurfaces in projective schemes and a moving lemmaApr 22 2014Let X/S be a quasi-projective morphism over an affine base. We develop in this article a technique for proving the existence of closed subschemes H/S of X/S with various favorable properties. We offer several applications of this technique, including ... More
Cooling of relativistic electron beams in chirped laser pulsesMay 18 2015The next few years will see next-generation high-power laser facilities (such as the Extreme Light Infrastructure) become operational, for which it is important to understand how interaction with intense laser pulses affects the bulk properties of a relativistic ... More
Shape-design for stabilizing micro-particles in inertial microfluidic flowsFeb 15 2019Design of microparticles which stabilize at the centerline of a channel flow when part of a dilute suspension is examined numerically for moderate Reynolds numbers ($10 \le Re \le 80$). Stability metrics for particles with arbitrary shapes are formulated ... More
Land Cover Classification via Multi-temporal Spatial Data by Recurrent Neural NetworksApr 13 2017Nowadays, modern earth observation programs produce huge volumes of satellite images time series (SITS) that can be useful to monitor geographical areas through time. How to efficiently analyze such kind of information is still an open question in the ... More
Degrees of bi-embeddable categoricity of equivalence structuresOct 30 2017We study the algorithmic complexity of embeddings between bi-embeddable equivalence structures. We define the notions of computable bi-embeddable categoricity, (relative) $\Delta^0_\alpha$ bi-embeddable categoricity, and degrees of bi-embeddable categoricity. ... More
Noise Contrastive Meta-Learning for Conditional Density Estimation using Kernel Mean EmbeddingsJun 05 2019Current meta-learning approaches focus on learning functional representations of relationships between variables, i.e. on estimating conditional expectations in regression. In many applications, however, we are faced with conditional distributions which ... More
Effect of nematic ordering on the elasticity and yielding in disordered polymeric solidsNov 16 2018The relation between elasticity and yielding is investigated in a model polymer solid by Molecular-Dynamics simulations. By changing the bending stiffness of the chain and the bond length, semicrystalline and disordered glassy polymers - both with bond ... More
Cherenkov radiation from the quantum vacuumOct 11 2018Mar 21 2019A charged particle moving through a medium emits Cherenkov radiation when its velocity exceeds the phase velocity of light in that medium. Under the influence of a strong electromagnetic field, quantum fluctuations can become polarized, imbuing the vacuum ... More
Detecting causal associations in large nonlinear time series datasetsFeb 22 2017Jun 28 2018Identifying causal relationships from observational time series data is a key problem in disciplines such as climate science or neuroscience, where experiments are often not possible. Data-driven causal inference is challenging since datasets are often ... More
Runtime Verification Based on Register AutomataSep 24 2012Jan 20 2015We propose TOPL automata as a new method for runtime verification of systems with unbounded resource generation. Paradigmatic such systems are object-oriented programs which can dynamically generate an unbounded number of fresh object identities during ... More
Exotic Spinorial Structure and Black Holes in General RelativityOct 16 2018We explore different (and complementary) views of spinors and their exotic counterparts, linking the very existence of the later to the presence of black holes. Moreover, we investigate the effects of the exotic term in the Hawking radiation emission ... More
Hydrodynamic theory for granular gasesJan 18 2000Jan 19 2000A granular gas subjected to a permanent injection of energy is described by means of hydrodynamic equations derived from a moment expansion method. The method uses as reference function not a Maxwellian distribution $f_{\sf M}$ but a distribution $f_0 ... More
Fast Two-Sample Testing with Analytic Representations of Probability MeasuresJun 15 2015We propose a class of nonparametric two-sample tests with a cost linear in the sample size. Two tests are given, both based on an ensemble of distances between analytic functions representing each of the distributions. The first test uses smoothed empirical ... More
DuPLO: A DUal view Point deep Learning architecture for time series classificatiOnSep 20 2018Nowadays, modern Earth Observation systems continuously generate huge amounts of data. A notable example is represented by the Sentinel-2 mission, which provides images at high spatial resolution (up to 10m) with high temporal revisit period (every 5 ... More
Operator Precedence ω-languagesJan 11 2013Jul 02 2013\omega-languages are becoming more and more relevant nowadays when most applications are 'ever-running'. Recent literature, mainly under the motivation of widening the application of model checking techniques, extended the analysis of these languages ... More
DEMON: a Local-First Discovery Method for Overlapping CommunitiesJun 04 2012Community discovery in complex networks is an interesting problem with a number of applications, especially in the knowledge extraction task in social and information networks. However, many large networks often lack a particular community organization ... More
Kernel Sequential Monte CarloOct 11 2015Feb 16 2016Bayesian posterior inference with Monte Carlo methods has a fundamental role in statistics and probabilistic machine learning. Target posterior distributions arising in increasingly complex models often exhibit high degrees of nonlinearity and multimodality ... More
Deep learning is a good steganalysis tool when embedding key is reused for different images, even if there is a cover source-mismatchNov 16 2015Jan 12 2018Since the BOSS competition, in 2010, most steganalysis approaches use a learning methodology involving two steps: feature extraction, such as the Rich Models (RM), for the image representation, and use of the Ensemble Classifier (EC) for the learning ... More
Non-parametric change-point detection using string matching algorithmsJun 28 2011Jul 28 2011Given the output of a data source taking values in a finite alphabet, we wish to detect change-points, that is times when the statistical properties of the source change. Motivated by ideas of match lengths in information theory, we introduce a novel ... More
On the arithmetic of a family of degree-two K3 surfacesMar 06 2017Feb 25 2018Let $\mathbb{P}$ denote the weighted projective space with weights $(1,1,1,3)$ over the rationals, with coordinates $x,y,z,$ and $w$; let $\mathcal{X}$ be the generic element of the family of surfaces in $\mathbb{P}$ given by \begin{equation*} X\colon ... More
Direct Measurement of Particle Inertial Migration in Rectangular MicrochannelsSep 05 2015Jul 05 2017Particles traveling at high velocities through microfluidic channels migrate from their starting streamlines due to inertial lift forces. Theories predict different scaling laws for these forces and there is little experimental evidence by which to validate ... More
Gaussian Processes and Kernel Methods: A Review on Connections and EquivalencesJul 06 2018This paper is an attempt to bridge the conceptual gaps between researchers working on the two widely used approaches based on positive definite kernels: Bayesian learning or inference using Gaussian processes on the one side, and frequentist kernel methods ... More
Algorithmic bias amplifies opinion polarization: A bounded confidence modelMar 06 2018The flow of information reaching us via the online media platforms is optimized not by the information content or relevance but by popularity and proximity to the target. This is typically performed in order to maximise platform usage. As a side effect, ... More
Linear feature detection algorithm for astronomical surveys - II. Defocusing effects on meteor tracksJul 22 2017Given the current limited knowledge of meteor plasma micro-physics and its interaction with the surrounding atmosphere and ionosphere, meteors are a highly interesting observational target for high-resolution wide-field astronomical surveys. Such surveys ... More
Gradient-free Hamiltonian Monte Carlo with Efficient Kernel Exponential FamiliesJun 08 2015Nov 24 2015We propose Kernel Hamiltonian Monte Carlo (KMC), a gradient-free adaptive MCMC algorithm based on Hamiltonian Monte Carlo (HMC). On target densities where classical HMC is not an option due to intractable gradients, KMC adaptively learns the target's ... More
Equivalence of distance-based and RKHS-based statistics in hypothesis testingJul 25 2012Nov 12 2013We provide a unifying framework linking two classes of statistics used in two-sample and independence testing: on the one hand, the energy distances and distance covariances from the statistics literature; on the other, maximum mean discrepancies (MMD), ... More
Longitudinal and transverse cooling of relativistic electron beams in intense laser pulsesApr 14 2015May 18 2015With the emergence in the next few years of a new breed of high power laser facilities, it is becoming increasingly important to understand how interacting with intense laser pulses affects the bulk properties of a relativistic electron beam. A detailed ... More
Semi-classical beam cooling in an intense laser pulseOct 07 2014We present a novel technique for studying the evolution of a particle distribution using single particle dynamics such that the distribution can be accurately reconstructed using fewer particles than existing approaches. To demonstrate this, the Landau-Lifshiftz ... More
Direct Measurement of Particle Inertial Migration in Rectangular MicrochannelsSep 05 2015Particles traveling at high velocities through microfluidic channels migrate across streamlines due to inertial lift forces. There are contradictory theories predicting how the inertial lift force depends on flow parameters, but little experimental evidence ... More
Deep Learning for steganalysis is better than a Rich Model with an Ensemble Classifier, and is natively robust to the cover source-mismatchNov 16 2015Since the BOSS competition, in 2010, most steganalysis approaches use a learning methodology involving two steps: feature extraction, such as the Rich Models (RM), for the image representation, and use of the Ensemble Classifier (EC) for the learning ... More
Node-centric community detection in multilayer networks with layer-coverage diversification biasApr 11 2017The problem of node-centric, or local, community detection in information networks refers to the identification of a community for a given input node, having limited information about the network topology. Existing methods for solving this problem, however, ... More
Modeling Time in Computing: A Taxonomy and a Comparative SurveyJul 25 2008Oct 11 2010The increasing relevance of areas such as real-time and embedded systems, pervasive computing, hybrid systems control, and biological and social systems modeling is bringing a growing attention to the temporal aspects of computing, not only in the computer ... More