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Discretization of mixed formulations of elliptic problems on polyhedral meshesOct 19 2016We review basic design principles underpinning the construction of mimetic finite difference and a few finite volume and finite element schemes for mixed formulations of elliptic problems. For a class of low-order mixed-hybrid schemes, we show connections ... More

The virtual element method for eigenvalue problems with potential terms on polytopal meshesMar 31 2018We extend the conforming virtual element method to the numerical resolution of eigenvalue problems with potential terms on a polytopal mesh. An important application is that of the Schrodinger equation with a pseudopotential term. This model is a fundamental ... More

Annotations on the virtual element method for second-order elliptic problemsDec 29 2016This document contains working annotations on the Virtual Element Method (VEM) for the approximate solution of diffusion problems with variable coefficients. To read this document you are assumed to have familiarity with concepts from the numerical discretization ... More

Convergence of spectral discretizations of the Vlasov-Poisson systemDec 23 2016May 02 2017We prove the convergence of a spectral discretization of the Vlasov-Poisson system. The velocity term of the Vlasov equation is discretized using either Hermite functions on the infinite domain or Legendre polynomials on a bounded domain. The spatial ... More

Arbitrary-order time-accurate semi-Lagrangian spectral approximations of the Vlasov-Poisson systemMar 25 2018Apr 05 2018The Vlasov-Poisson system, modeling the evolution of non-collisional plasmas in the electrostatic limit, is approx- imated by a Semi-Lagrangian technique. Spectral methods of periodic type are implemented through a collocation approach. Groups of particles ... More

A Semi-Lagrangian Spectral Method for the Vlasov-Poisson System based on Fourier, Legendre and Hermite PolynomialsJul 05 2018In this work, we apply a semi-Lagrangian spectral method for the Vlasov-Poisson system, previously designed for periodic Fourier discretizations, by implementing Legendre polynomials and Hermite functions in the approximation of the distribution function ... More

Conforming and nonconforming virtual element methods for elliptic problemsJul 13 2015We present in a unified framework new conforming and nonconforming Virtual Element Methods (VEM) for general second order elliptic problems in two and three dimensions. The differential operator is split into its symmetric and non-symmetric parts and ... More

The non-conforming virtual element method for the Stokes equationsAug 03 2016Sep 06 2016We present the non-conforming Virtual Element Method (VEM) for the numerical approximation of velocity and pressure in the steady Stokes problem. The pressure is approximated using discontinuous piecewise polynomials, while each component of the velocity ... More

The nonconforming virtual element method for eigenvalue problemsFeb 08 2018We analyse the nonconforming Virtual Element Method (VEM) for the approximation of elliptic eigenvalue problems. The nonconforming VEM allow to treat in the same formulation the two- and three-dimensional case.We present two possible formulations of the ... More

SUPG stabilization for the nonconforming virtual element method for advection-diffusion-reaction equationsJun 03 2018We present the design, convergence analysis and numerical investigations of the nonconforming virtual element method with Streamline Upwind/Petrov-Galerkin (VEM-SUPG) stabilization for the numerical resolution of convection-diffusion-reaction problems ... More

From H&M to Gap for Lightweight BWT MergingSep 15 2016Recently, Holt and McMillan [Bionformatics 2014, ACM-BCB 2014] have proposed a simple and elegant algorithm to merge the Burrows-Wheeler transforms of a family of strings. In this paper we show that the H&M algorithm can be improved so that, in addition ... More

On geodesic envelopes and causticsNov 19 2004Dec 09 2005We give a global description of envelopes of geodesic tangents of regular curves in (not necessarily convex) Riemannian surfaces. We prove that such an envelope is the union of the curve itself, its inflectional geodesics and its tangential caustics (formed ... More

Hecke algebra with respect to the pro-$p$-radical of a maximal compact open subgroup for $GL(n,F)$ and its inner formsMay 25 2016Let $G$ be a direct product of inner forms of general linear groups over non-archimedean locally compact fields of residue characteristic $p$ and let $K^1$ be the pro-$p$-radical of a maximal compact open subgroup of $G$. In this paper we describe the ... More

Further remarks on the Luo-Hou's ansatz for a self-similar solution to the 3D Euler equationsAug 31 2017It is shown that the self-similar ansatz proposed by T. Hou and G. Luo to describe a singular solution of the 3D axisymmetric Euler equations leads, without assuming any asymptotic condition on the self-similar profiles, to an over-determined system of ... More

Stable tangential families and singularities of their envelopesJun 28 2004We study tangential families, i.e. systems of rays emanating tangentially from given curves. We classify, up to Left-Right equivalence, stable singularities of tangential family germs (under deformations among tangential families) and we study their envelopes. ... More

Hecke algebra with respect to the pro-$p$-radical of a maximal compact open subgroup for $GL(n,F)$ and its inner formsMay 25 2016Jan 25 2017Let $G$ be a direct product of inner forms of general linear groups over non-archimedean locally compact fields of residue characteristic $p$ and let $K^1$ be the pro-$p$-radical of a maximal compact open subgroup of $G$. In this paper we describe the ... More

Discontinuous Skeletal Gradient Discretisation Methods on polytopal meshesJun 29 2017Dec 06 2017In this work we develop arbitrary-order Discontinuous Skeletal Gradient Discretisations (DSGD) on general polytopal meshes. Discontinuous Skeletal refers to the fact that the globally coupled unknowns are broken polynomial on the mesh skeleton. The key ... More

Cusp singularities of plane envelopesNov 21 2005We consider smooth 1-parameter families of plane curves tangent to a semicubic parabola, when the curvature radius of their curves at the tangency point vanishes at the cusp point. We find the $\A$-normal form of these families, their envelopes and local ... More

An alternative approach to heavy-traffic limits for finite-pool queuesNov 23 2018We consider a model for transitory queues in which only a finite number of customers can join. The queue thus operates over a finite time horizon. In this system, also known as the $\Delta_{(i)}/G/1$ queue, the customers decide independently when to join ... More

Simple tangential families and perestroikas of their envelopesSep 06 2004Tangential families are 1-parameter families of rays emanating tangentially from smooth curves. We classify tangential family germs up to Left-Right equivalence: we prove that there are two infinite series and four sporadic simple singularities of tangential ... More

Generic singularities of minimax solutions to Hamilton--Jacobi equationsJul 05 2004Minimax solutions are weak solutions to Cauchy problems involving Hamilton--Jacobi equations, constructed from generating families quadratic at infinity of their geometric solutions. We give a complete description of minimax solutions and we classify ... More

Higher dimensional holonomy map for ruled submanifolds in graded manifoldsJun 12 2019The deformability condition for submanifolds of fixed degree immersed in a graded manifold can be expressed as a system of first order PDEs. In the particular case of ruled submanifolds, we introduce a natural choice of coordinates, which allows to deeply ... More

Blocks of the category of smooth $\ell$-modular representations of $GL(n,F)$ and its inner forms: reduction to level-$0$May 15 2017Let $G$ be an inner form of a general linear group over a non-archimedean locally compact field of residue characteristic $p$, let $R$ be an algebraically closed field of characteristic different from $p$ and let $\mathscr{R}_R(G)$ be the category of ... More

Legendrian graphs generated by Tangential FamiliesSep 29 2004We construct a Legendrian version of Envelope theory. A tangential family is a 1-parameter family of rays emanating tangentially from a smooth plane curve. The Legendrian graph of the family is the union of the Legendrian lifts of the family curves in ... More

Toward a Succinct Index for Order-Preserving Pattern MatchingOct 10 2016Although introduced only a few years ago, the problem of order-preserving pattern matching has already attracted significant attention. In this paper we introduce the first index for this problem that uses sublinear space in addition to the data, which ... More

Compressing and Indexing Stock Market DataJun 18 2016Sep 13 2016We show how to build a compressed index for the offline Order Preserving Pattern Matching problem. Our solution is based on the new approach of decomposing the sequence to be indexed into an order component, containing ordering information, and a delta ... More

Lightweight merging of compressed indices based on BWT variantsMar 04 2019In this paper we propose a flexible and lightweight technique for merging compressed indices based on variants of Burrows-Wheeler transform (BWT), thus addressing the need for algorithms that compute compressed indices over large collections using a limited ... More

Perestroikas of vertex sets at umbilic pointsMar 14 2006Aug 14 2007Mark all vertices on a curve evolving under a family of curves obtained by intersecting a smooth surface M with the 1-parameter family of planes parallel to the tangent plane to M at a point p. Those vertices trace out a set, called the vertex set of ... More

Thresholds for hanger slackening and cable shortening in the Melan equation for suspension bridgesAug 31 2017The Melan equation for suspension bridges is derived by assuming small displacements of the deck and inextensible hangers. We determine the thresholds for the validity of the Melan equation when the hangers slacken, thereby violating the inextensibility ... More

Compressed Spaced Suffix ArraysDec 12 2013Mar 09 2014Spaced seeds are important tools for similarity search in bioinformatics, and using several seeds together often significantly improves their performance. With existing approaches, however, for each seed we keep a separate linear-size data structure, ... More

Space-efficient merging of succinct de Bruijn graphsFeb 07 2019Mar 06 2019We propose a new algorithm for merging succinct representations of de Bruijn graphs introduced in [Bowe et al. WABI 2012]. Our algorithm is based on the lightweight BWT merging approach by Holt and McMillan [Bionformatics 2014, ACM-BCB 2014]. Our algorithm ... More

The Wigner-Poisson-Fokker-Planck system: global-in-time solution and dispersive estimatesMay 18 2005This paper is concerned with the Wigner-Poisson-Fokker-Planck system, a kinetic evolution equation for an open quantum system with a non-linear Hartree potential. Existence, uniqueness and regularity of global solutions to the Cauchy problem in 3 dimensions ... More

Space-efficient merging of succinct de Bruijn graphsFeb 07 2019We propose a new algorithm for merging succinct representations of de Bruijn graphs introduced in [Bowe et al. WABI 2012]. Our algorithm is inspired by the approach introduced by Holt and McMillan [Bionformatics 2014, ACM-BCB 2014] for merging Burrow-Wheeler ... More

Space-efficient merging of succinct de Bruijn graphsFeb 07 2019May 30 2019We propose a new algorithm for merging succinct representations of de Bruijn graphs introduced in [Bowe et al. WABI 2012]. Our algorithm is based on the lightweight BWT merging approach by Holt and McMillan [Bionformatics 2014, ACM-BCB 2014]. Our algorithm ... More

The fully nonconforming virtual element method for biharmonic problemsNov 26 2016In this paper we address the numerical approximation of linear fourth-order elliptic problems on polygonal meshes. In particular, we present a novel nonconforming virtual element discretization of arbitrary order of accuracy for biharmonic problems. The ... More

Lightweight Data Indexing and Compression in External MemorySep 24 2009In this paper we describe algorithms for computing the BWT and for building (compressed) indexes in external memory. The innovative feature of our algorithms is that they are lightweight in the sense that, for an input of size $n$, they use only ${n}$ ... More

Theoretical study of an adaptive cubic regularization method with dynamic inexact Hessian informationAug 19 2018We consider the Adaptive Regularization with Cubics approach for solving nonconvex optimization problems and propose a new variant based on inexact Hessian information chosen dynamically. The theoretical analysis of the proposed procedure is given. The ... More

Analysis of Energy and QUadratic Invariant Preserving (EQUIP) methodsMay 15 2017Nov 29 2017In this paper we are concerned with the analysis of a class of geometric integrators, at first devised in [14, 18], which can be regarded as an energy-conserving variant of Gauss collocation methods. With these latter they share the property of conserving ... More

Online wheel speed filtering for periodic disturbance reduction: a strategy for an advanced bicycle applicationOct 04 2016Oct 05 2016Due to geometrical errors and possible misalignment of the sensors, wheel speed measurements provided by incremental encoders in road vehicles are usually affected by significant periodic noises. This paper presents an online wheel speed filtering procedure, ... More

Spectrally Accurate Energy-preserving Methods for the Numerical Solution of the "Good" Boussinesq EquationJul 13 2018In this paper we study the geometric solution of the so called "good" Boussinesq equation. This goal is achieved by using a convenient space semi-discretization, able to preserve the corresponding Hamiltonian structure, then using energy-conserving Runge-Kutta ... More

Variational formulas for curves of fixed degreeFeb 11 2019We consider a length functional for $C^1$ curves of fixed degree in graded manifolds equipped with a Riemannian metric. The first variation of this length functional can be computed only if the curve can be deformed in a suitable sense, and this condition ... More

ssMousetrack: Analysing computerized tracking data via Bayesian state-space models in {R}Apr 23 2019Recent technological advances have provided new settings to enhance individual-based data collection and computerized-tracking data have became common in many behavioral and social research. By adopting instantaneous tracking devices such as computer-mouse, ... More

Variational formulas for submanifolds of fixed degreeMay 13 2019We consider in this paper an area functional defined on submanifolds of fixed degree immersed into a graded manifold equipped with a Riemannian metric. Since the expression of this area depends on the degree, not all variations are admissible. It turns ... More

External memory BWT and LCP computation for sequence collections with applicationsMay 17 2018We propose an external memory algorithm for the computation of the BWT and LCP array for a collection of sequences. Our algorithm takes the amount of available memory as an input parameter, and tries to make the best use of it by splitting the input collection ... More

Reusing an FM-indexApr 18 2014May 09 2014Intuitively, if two strings $S_1$ and $S_2$ are sufficiently similar and we already have an FM-index for $S_1$ then, by storing a little extra information, we should be able to reuse parts of that index in an FM-index for $S_2$. We formalize this intuition ... More

Relative SelectJun 10 2015Motivated by the problem of storing coloured de Bruijn graphs, we show how, if we can already support fast select queries on one string, then we can store a little extra information and support fairly fast select queries on a similar string.

Black is to Criminal as Caucasian is to Police: Detecting and Removing Multiclass Bias in Word EmbeddingsApr 03 2019May 13 2019Online texts -- across genres, registers, domains, and styles -- are riddled with human stereotypes, expressed in overt or subtle ways. Word embeddings, trained on these texts, perpetuate and amplify these stereotypes, and propagate biases to machine ... More

Efficient and Compact Representations of Some Non-Canonical Prefix-Free CodesMay 21 2016For many kinds of prefix-free codes there are efficient and compact alternatives to the traditional tree-based representation. Since these put the codes into canonical form, however, they can only be used when we can choose the order in which codewords ... More

Efficient and Compact Representations of Some Non-Canonical Prefix-Free CodesMay 21 2016Dec 14 2016For many kinds of prefix-free codes there are efficient and compact alternatives to the traditional tree-based representation. Since these put the codes into canonical form, however, they can only be used when we can choose the order in which codewords ... More

A random telegraph signal of Mittag-Leffler typeAug 19 2008A general method is presented to explicitly compute autocovariance functions for non-Poisson dichotomous noise based on renewal theory. The method is specialized to a random telegraph signal of Mittag-Leffler type. Analytical predictions are compared ... More

Black is to Criminal as Caucasian is to Police:Detecting and Removing Multiclass Bias in Word EmbeddingsApr 03 2019Online texts -- across genres, registers, domains, and styles -- are riddled with human stereotypes, expressed in overt or subtle ways. Word embeddings, trained on these texts, perpetuate and amplify these stereotypes, and propagate biases to machine ... More

A Legendre-Fourier spectral method with exact conservation laws for the Vlasov-Poisson systemSep 30 2016We present the design and implementation of an L2-stable spectral method for the discretization of the Vlasov- Poisson model of a collisionless plasma in one space and velocity dimension. The velocity and space dependence of the Vlasov equation are resolved ... More

Convergence analysis of the mimetic finite difference method for elliptic problems with staggered discretization of the diffusion coefficientsDec 06 2016We study the convergence of the new family of mimetic finite difference schemes for linear diffusion problems recently proposed in [38]. In contrast to the conventional approach, the diffusion coefficient enters both the primary mimetic operator, i.e., ... More

The nonconforming virtual element methodMay 15 2014May 16 2014We introduce the nonconforming Virtual Element Method (VEM) for the approximation of second order elliptic problems. We present the construction of the new element in two and three dimensions, highlighting the main differences with the conforming VEM ... More

A posteriori error estimation and adaptivity in $hp$ virtual elementsApr 21 2018An explicit and computable error estimator for the $hp$ version of the virtual element method (VEM), together with lower and upper bounds with respect to the exact energy error, is presented. Such error estimator is employed to provide $hp$ adaptive mesh ... More

On the calculation of potential of mean force between atomistic nanoparticlesMar 07 2018We study the potential of mean force (PMF) between atomistic silica and gold nanoparticles in the vacuum by using molecular dynamics simulations. Such an investigation is devised in order to fully characterize the effective interactions between atomistic ... More

The Effect of Collective Attention on Controversial Debates on Social MediaMay 16 2017We study the evolution of long-lived controversial debates as manifested on Twitter from 2011 to 2016. Specifically, we explore how the structure of interactions and content of discussion varies with the level of collective attention, as evidenced by ... More

A note on the birefringence angle estimation in CMB data analysisApr 18 2016Apr 26 2016Parity violating physics beyond the standard model of particle physics induces a rotation of the linear polarization of photons. This effect, also known as cosmological birefringence (CB), can be tested with the observations of the cosmic microwave background ... More

The Ebb and Flow of Controversial Debates on Social MediaMar 17 2017We explore how the polarization around controversial topics evolves on Twitter - over a long period of time (2011 to 2016), and also as a response to major external events that lead to increased related activity. We find that increased activity is typically ... More

A Maximum Entropy Procedure to Solve Likelihood EquationsApr 22 2019Jun 13 2019In this article we provide initial findings regarding the problem of solving likelihood equations by means of a maximum entropy approach. Unlike standard procedures that require equating at zero the score function of the maximum-likelihood problem, we ... More

Quantifying Controversy in Social MediaJul 18 2015Jun 07 2016Which topics spark the most heated debates on social media? Identifying those topics is not only interesting from a societal point of view, but also allows the filtering and aggregation of social media content for disseminating news stories. In this paper, ... More

Scalable Online Betweenness Centrality in Evolving GraphsJan 27 2014Apr 28 2015Betweenness centrality is a classic measure that quantifies the importance of a graph element (vertex or edge) according to the fraction of shortest paths passing through it. This measure is notoriously expensive to compute, and the best known algorithm ... More

A Maximum Entropy Procedure to Solve Likelihood EquationsApr 22 2019May 20 2019In this article we provide initial findings regarding the problem of solving likelihood equations by means of a maximum entropy approach. Unlike standard procedures that require equating at zero the score function of the maximum-likelihood problem, we ... More

Says who? Automatic Text-Based Content Analysis of Television NewsJul 18 2013Aug 29 2013We perform an automatic analysis of television news programs, based on the closed captions that accompany them. Specifically, we collect all the news broadcasted in over 140 television channels in the US during a period of six months. We start by segmenting, ... More

Line Integral Solution of Hamiltonian Systems with Holonomic ConstraintsApr 26 2017Dec 18 2017In this paper, we propose a second-order energy-conserving approximation procedure for Hamiltonian systems with holonomic constraints. The derivation of the procedure relies on the use of the so-called line integral framework. We provide numerical experiments ... More

Balancing Opposing Views to Reduce ControversyNov 01 2016Society is often polarized by controversial issues, that split the population into groups of opposing views. When such issues emerge on social media, we often observe the creation of 'echo chambers', i.e., situations where like-minded people reinforce ... More

Self-assembly in a model colloidal mixture of dimers and spherical particlesFeb 23 2017We investigate the structure of a dilute mixture of amphiphilic dimers and spherical particles, a model relevant to the problem of encapsulating globular "guest" molecules in a dispersion. Dimers and spheres are taken to be hard particles, with an additional ... More

Structure and phase behavior of colloidal dumbbells with tunable attractive interactionsOct 16 2013We investigate thermodynamic and structural properties of colloidal dumbbells in the framework provided by the Reference Interaction Site Model (RISM) theory of molecular fluids and Monte Carlo simulations. We consider two different models: in the first ... More

The microarchitecture of a multi-threaded RISC-V compliant processing core family for IoT end-nodesDec 13 2017Internet-of-Things end-nodes demand low power processing platforms characterized by heterogeneous dedicated units, controlled by a processor core running concurrent control threads. Such architecture scheme fits one of the main target application domain ... More

Non-modal analysis of spectral element methods: Towards accurate and robust large-eddy simulationsApr 25 2018We introduce a \textit{non-modal} analysis technique that characterizes the diffusion properties of spectral element methods for linear convection-diffusion systems. While strictly speaking only valid for linear problems, the analysis is devised so that ... More

Super resolution imaging through the human skullNov 26 2018High resolution transcranial ultrasound imaging in humans has been a persistent challenge for ultrasound due to the imaging degradation effects from aberration and reverberation. These mechanisms depend strongly on skull morphology and they have high ... More

VHT: Vertical Hoeffding TreeJul 28 2016IoT Big Data requires new machine learning methods able to scale to large size of data arriving at high speed. Decision trees are popular machine learning models since they are very effective, yet easy to interpret and visualize. In the literature, we ... More

Large-Scale Learning from Data Streams with Apache SAMOAMay 26 2018Apache SAMOA (Scalable Advanced Massive Online Analysis) is an open-source platform for mining big data streams. Big data is defined as datasets whose size is beyond the ability of typical software tools to capture, store, manage, and analyze, due to ... More

Sharp Strichartz inequalities for fractional and higher order Schrödinger equationsApr 30 2018Jul 11 2018We investigate a class of sharp Fourier extension inequalities on the planar curves $s=|y|^p$, $p>1$. We identify the mechanism responsible for the possible loss of compactness of nonnegative extremizing sequences, and prove that extremizers exist if ... More

Rpair: Rescaling RePair with RsyncJun 03 2019Data compression is a powerful tool for managing massive but repetitive datasets, especially schemes such as grammar-based compression that support computation over the data without decompressing it. In the best case such a scheme takes a dataset so big ... More

Inducing the Lyndon ArrayMay 30 2019In this paper we propose a variant of the induced suffix sorting algorithm by Nong (TOIS, 2013) that computes simultaneously the Lyndon array and the suffix array of a text in $O(n)$ time using $\sigma + O(1)$ words of working space, where $n$ is the ... More

Lyndon Array Construction during Burrows-Wheeler InversionOct 27 2017In this paper we present an algorithm to compute the Lyndon array of a string $T$ of length $n$ as a byproduct of the inversion of the Burrows-Wheeler transform of $T$. Our algorithm runs in linear time using only a stack in addition to the data structures ... More

Comet McNaught (260P/2012 K2): spin axis orientation and rotation periodMar 22 2014Extensive observations of comet 260P (McNaught) were carried out between August 2012 and January 2013. The images obtained were used to analyze the inner coma morphology of the comet at resolutions ranging from 250 to about 1000 km/pixel. A deep investigation ... More

Efficient Construction of a Complete Index for Pan-Genomics Read AlignmentNov 16 2018While short read aligners, which predominantly use the FM-index, are able to easily index one or a few human genomes, they do not scale well to indexing databases containing thousands of genomes. To understand why, it helps to examine the main components ... More

Prefix-Free Parsing for Building Big BWTsMar 29 2018Nov 16 2018High-throughput sequencing technologies have led to explosive growth of genomic databases; one of which will soon reach hundreds of terabytes. For many applications we want to build and store indexes of these databases but constructing such indexes is ... More

The Power of Both Choices: Practical Load Balancing for Distributed Stream Processing EnginesApr 03 2015We study the problem of load balancing in distributed stream processing engines, which is exacerbated in the presence of skew. We introduce Partial Key Grouping (PKG), a new stream partitioning scheme that adapts the classical "power of two choices" to ... More

Reference Interaction Site Model and Optimized Perturbation theories of colloidal dumbbells with increasing anisotropyMay 26 2015We investigate thermodynamic properties of anisotropic colloidal dumbbells in the frameworks provided by the Reference Interaction Site Model (RISM) theory and an Optimized Perturbation Theory (OPT), this latter based on a fourth-order high-temperature ... More

Partial Key Grouping: Load-Balanced Partitioning of Distributed StreamsOct 26 2015We study the problem of load balancing in distributed stream processing engines, which is exacerbated in the presence of skew. We introduce Partial Key Grouping (PKG), a new stream partitioning scheme that adapts the classical "power of two choices" to ... More

Mining Frequent Patterns in Evolving GraphsSep 02 2018Sep 10 2018Given a labeled graph, the frequent-subgraph mining (FSM) problem asks to find all the $k$-vertex subgraphs that appear with frequency greater than a given threshold. FSM has numerous applications ranging from biology to network science, as it provides ... More

When Two Choices Are not Enough: Balancing at Scale in Distributed Stream ProcessingOct 19 2015Jan 27 2016Carefully balancing load in distributed stream processing systems has a fundamental impact on execution latency and throughput. Load balancing is challenging because real-world workloads are skewed: some tuples in the stream are associated to keys which ... More

Unsupervised Data Selection for Supervised LearningOct 29 2018Dec 19 2018Recent research put a big effort in the development of deep learning architectures and optimizers obtaining impressive results in areas ranging from vision to language processing. However little attention has been addressed to the need of a methodological ... More

Flux measurement of fast neutrons in the Gran Sasso underground laboratoryMay 14 2019The neutron energy spectrum for energies between 5 and 15 MeV has been measured in the INFN Laboratori Nazionali del Gran Sasso in Italy, by using a $1.5~m^3$ stainless-steel tank filled with 1.2 ton Gd-doped liquid scintillator. A two-pulse signature, ... More

Fully Dynamic Algorithm for Top-$k$ Densest SubgraphsOct 19 2016Aug 29 2017Given a large graph, the densest-subgraph problem asks to find a subgraph with maximum average degree. When considering the top-$k$ version of this problem, a na\"ive solution is to iteratively find the densest subgraph and remove it in each iteration. ... More

Cluster formation and phase separation in heteronuclear Janus dumbbellsDec 04 2014We have recently investigated the phase behaviour of model colloidal dumbbells constituted by two identical tangent hard spheres, with the first one being surrounded by an attractive square-well interaction (Janus dumbbells, Muna\`o G et al 2014 Soft ... More

Training of a Skull-Stripping Neural Network with efficient data augmentationOct 25 2018Skull-stripping methods aim to remove the non-brain tissue from acquisition of brain scans in magnetic resonance (MR) imaging. Although several methods sharing this common purpose have been presented in literature, they all suffer from the great variability ... More

Density and structural anomalies in soft-repulsive dimeric fluidsMar 07 2016We report Monte Carlo results for the fluid structure of a system of dimeric particles interacting via a core-softened potential. More specifically, dimers interact through a repulsive pair potential of inverse-power form, modified in such a way that ... More

Heavy-traffic analysis through uniform acceleration of queues with diminishing populationsDec 17 2014Nov 30 2015We consider a single server queue that serves a finite population of $n$ customers that will enter the queue (require service) only once, also known as the $\Delta_{(i)}/G/1$ queue. This paper presents a method for analyzing heavy-traffic behavior by ... More

Big jobs arrive early: From critical queues to random graphsApr 11 2017We consider a queue to which only a finite pool of $n$ customers can arrive, at times depending on their service requirement. A customer with stochastic service requirement $S$ arrives to the queue after an exponentially distributed time with mean $S^{-\alpha}$ ... More

Top-k densest subgraphs in sliding-window graph streamsOct 19 2016Given a large graph, the densest-subgraph problem asks to find a subgraph with maximum average degree. When considering the top-k version of this problem, a naive solution is to iteratively find the densest subgraph and remove it in each iteration. However, ... More

Integral equation study of soft-repulsive dimeric fluidsDec 15 2016We study fluid structure and water-like anomalies of a system constituted by dimeric particles interacting via a purely repulsive core-softened potential by means of integral equation theories. In our model, dimers interact through a repulsive pair potential ... More

Minimum-Variance Importance-Sampling Bernoulli Estimator for Fast Simulation of Linear Block Codes over Binary Symmetric ChannelsNov 06 2013In this paper the choice of the Bernoulli distribution as biased distribution for importance sampling (IS) Monte-Carlo (MC) simulation of linear block codes over binary symmetric channels (BSCs) is studied. Based on the analytical derivation of the optimal ... More

Weil representations and metaplectic groups over an integral domainSep 20 2013Given F a locally compact, non-discrete, non-archimedean field of characteristic different from 2 and R an integral domain such that a non-trivial smooth F-character with values in the multiplicative group of R exists, we construct the (reduced) metaplectic ... More

Convolutional Neural Networks for the segmentation of microcalcification in Mammography ImagingSep 11 2018Cluster of microcalcifications can be an early sign of breast cancer. In this paper we propose a novel approach based on convolutional neural networks for the detection and segmentation of microcalcification clusters. In this work we used 283 mammograms ... More

Finite-pool queues with heavy-tailed servicesMay 20 2016We consider the $\Delta_{(i)}/G/1$ queue, in which a a total of $n$ customers independently demand service after an exponential time. We focus on the case of heavy-tailed service times, and assume that the tail of the service time distribution decays ... More

Molecular Structure and Multi-Body Potential of Mean Force in Silica-Polystyrene NanocompositesSep 17 2018We perform a systematic application of the hybrid particle-field molecular dynamics technique [Milano et al, J. Chem. Phys. 2009, 130, 214106] to study interfacial properties and potential of mean force (PMF) for separating nanoparticles (NPs) in a melt. ... More