Results for "Jimmy Gonzalez Nunez"

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Dynamical BCS theory of a two-dimensional attractive Fermi gas: effective interactions from Quantum Monte Carlo calculationsMay 14 2019The primary work presented in this paper focuses on the calculation of density-density dynamical correlations in an attractive two dimensional Fermi gas in several physically interesting regimes, including the strongly correlated BEC-BCS crossover regime. ... More
A power series identity and Bessel-type integrals over unitary groupsJun 06 2018In 2008, Lehner, Wettig, Guhr and Wei conjectured a power series identity and showed that it implied a determinantal formula for a Bessel-type integral over the unitary supergroup. The integral is the supersymmetric extension of Bessel-type integrals ... More
Example of an order 16 non symplectic action on a K3 surfaceFeb 10 2015Aug 19 2015We exhibit an example of a K3 surface of Picard rank $14$ with a non-symplectic automorphism of order $16$ which fixes a rational curve and $10$ isolated points. This settles the existence problem for the last case of Al Tabbaa, Sarti and Taki's classification. ... More
The Simplest Thing That Can Possibly Work: Pseudo-Relevance Feedback Using Text ClassificationApr 18 2019Motivated by recent commentary that has questioned today's pursuit of ever-more complex models and mathematical formalisms in applied machine learning and whether meaningful empirical progress is actually being made, this paper tries to tackle the decades-old ... More
Bisymmetric and quasitrivial operations: characterizations and enumerationsDec 21 2017Jan 16 2018We investigate the class of bisymmetric and quasitrivial binary operations on a given set $X$ and provide various characterizations of this class as well as the subclass of bisymmetric, quasitrivial, and order-preserving binary operations. We also determine ... More
Statistical mechanics of neocortical interactions: High resolution path-integral calculation of short-term memoryJan 24 2000We present high-resolution path-integral calculations of a previously developed model of short-term memory in neocortex. These calculations, made possible with supercomputer resources, supplant similar calculations made in L. Ingber, Phys. Rev. E 49, ... More
Characterizations of biselective operationsJun 06 2018Jun 18 2018Let $X$ be a nonempty set and let $i,j \in \{1,2,3,4\}$. We say that a binary operation $F:X^2\to X$ is $(i,j)$-selective if $$ F(F(x_1,x_2),F(x_3,x_4))~=~F(x_i,x_j), $$ for all $x_1,x_2,x_3,x_4\in X$. In this paper we provide characterizations of the ... More
Metrics of constant scalar curvature on sphere bundlesJun 04 2015Mar 08 2016Let $G/H$ be a Riemannian homogeneous space. For an orthogonal representation $\phi$ of $H$ on the Euclidean space $\mathbb{R}^{k+1}$, there corresponds the vector bundle $E=G\times_{\phi}\mathbb{R}^{k+1} \to G/H$ with fiberwise inner product. Provided ... More
A special case of Postnikov-Shapiro conjectureJul 22 2013Feb 14 2014For a graph $G$, Postnikov-Shapiro \cite{PS04} construct two ideals $I_G$ and $J_G.$ $I_G$ is a monomial ideal and $J_G$ is generated by powers of linear forms. They proved the equality of their Hilbert series and conjectured that the graded Betti numbers ... More
The absolute continuity of convolution products of orbital measures in exceptional symmetric spacesNov 18 2015Let $G$ be a non-compact group, $K$ the compact subgroup fixed by a Cartan involution and assume $G/K$ is an exceptional, symmetric space, one of Cartan type $E,F $ or $G$. We find the minimal integer, $L(G),$ such that any convolution product of $L(G)$ ... More
Split Dimensional Regularization for the Coulomb GaugeJan 10 1996May 24 1996A new procedure for regularizing Feynman integrals in the noncovariant Coulomb gauge is proposed for Yang-Mills theory. The procedure is based on a variant of dimensional regularization, called split dimensional regularization, which leads to internally ... More
Honk: A PyTorch Reimplementation of Convolutional Neural Networks for Keyword SpottingOct 18 2017Nov 28 2017We describe Honk, an open-source PyTorch reimplementation of convolutional neural networks for keyword spotting that are included as examples in TensorFlow. These models are useful for recognizing "command triggers" in speech-based interfaces (e.g., "Hey ... More
Exploring Model-based Planning with Policy NetworksJun 20 2019Model-based reinforcement learning (MBRL) with model-predictive control or online planning has shown great potential for locomotion control tasks in terms of both sample efficiency and asymptotic performance. Despite their initial successes, the existing ... More
Serverless Data Analytics with FlintMar 16 2018Oct 10 2018Serverless architectures organized around loosely-coupled function invocations represent an emerging design for many applications. Recent work mostly focuses on user-facing products and event-driven processing pipelines. In this paper, we explore a completely ... More
Bifurcation for the constant scalar curvature equation and harmonic Riemannian submersionsNov 21 2016Aug 16 2018We study bifurcation for the constant scalar curvature equation along a one-parameter family of Riemannian metrics on the total space of a harmonic Riemannian submersion. We provide an existence theorem for bifurcation points and a criterion to see that ... More
Isoparametric hypersurfaces and metrics of constant scalar curvatureMar 01 2011Sep 02 2013We showed the existence of non-radial solutions of the equation $\Delta u -\lambda u + \lambda u^q =0$ on the round sphere $S^m$, for $q<2m/(m-2)$, and study the number of such solutions in terms of $\lambda$. We show that for any isoparametric hypersurface ... More
Existence and regularity of Faber Krahn minimizers in a Riemannian manifoldJul 18 2019In this paper, we study the minimization of $\lambda_{1}(\Omega)$, the first Dirichlet eigenvalue of the Laplace-Beltrami operator, within the class of open sets $\Omega$ of fixed volume in a Riemmanian manifold $(M,g)$. In the Euclidian setting (when ... More
Neocortical Dynamics at Multiple Scales: EEG Standing Waves, Statistical Mechanics, and Physical AnalogsApr 25 2010The dynamic behavior of scalp potentials (EEG) is apparently due to some combination of global and local processes with important top-down and bottom-up interactions across spatial scales. In treating global mechanisms, we stress the importance of myelinated ... More
Relationship Detection Measures for Binary SoC DataMay 10 2019Jul 05 2019System-on-Chip (SoC) designs are used in every aspect of computing and their optimization is a difficult but essential task in today's competitive market. Data taken from SoCs to achieve this is often characterised by very long parallel streams of binary ... More
Efficient particle-based online smoothing in general hidden Markov models: the PaRIS algorithmDec 23 2014This paper presents a novel algorithm, the particle-based, rapid incremental smoother (PaRIS), for efficient online approximation of smoothed expectations of additive state functionals in general hidden Markov models. The algorithm, which has a linear ... More
Particle-based adaptive-lag online marginal smoothing in general state-space modelsDec 28 2018Jun 24 2019We present a novel algorithm, an adaptive-lag smoother, approximating efficiently, in an online fashion, sequences of expectations under the marginal smoothing distributions in general state-space models. The algorithm evolves recursively a bank of estimators, ... More
Fast, Incremental Inverted Indexing in Main Memory for Web-Scale CollectionsMay 03 2013For text retrieval systems, the assumption that all data structures reside in main memory is increasingly common. In this context, we present a novel incremental inverted indexing algorithm for web-scale collections that directly constructs compressed ... More
A Study of "Churn" in Tweets and Real-Time Search Queries (Extended Version)May 30 2012The real-time nature of Twitter means that term distributions in tweets and in search queries change rapidly: the most frequent terms in one hour may look very different from those in the next. Informally, we call this phenomenon "churn". Our interest ... More
Adaptive Pruning of Neural Language Models for Mobile DevicesSep 27 2018Neural language models (NLMs) exist in an accuracy-efficiency tradeoff space where better perplexity typically comes at the cost of greater computation complexity. In a software keyboard application on mobile devices, this translates into higher power ... More
Two-Loop Quark Self-Energy in a New Formalism (II): Renormalization of the Quark Propagator in the Light-Cone GaugeNov 25 1999The complete two-loop correction to the quark propagator, consisting of the spider, rainbow, gluon bubble and quark bubble diagrams, is evaluated in the noncovariant light-cone gauge (lcg). (The overlapping self-energy diagram had already been computed.) ... More
Afterburner: The Case for In-Browser AnalyticsMay 13 2016This paper explores the novel and unconventional idea of implementing an analytical RDBMS in pure JavaScript so that it runs completely inside a browser with no external dependencies. Our prototype, called Afterburner, generates compiled query plans that ... More
On the Yamabe constants of $S^2 \times \re^3$ and $S^3 \times \re^2$Feb 06 2012May 02 2012We compare the isoperimetric profiles of $S^2 \times \re^3$ and of $S^3 \times \re^2$ with that of a round 5-sphere (of appropriate radius). Then we use this comparison to obtain lower bounds for the Yamabe constants of $S^2 \times \re^3$ and $S^3 \times ... More
ICT, Community Memory and Technological AppropriationJun 06 2008The core mission of universities and higher education institutions is to make public the results of their work and to preserve the collective memory of the institution. This includes the effective use of information and communication technologies (ICT) ... More
Pressure variation of Luttinger liquids parameters in single wall carbon nanotubes networksJul 17 2006We measure electrical transport on networks of single wall nanotube of different origin as a function of temperature T, voltage V and pressure P . We observe Luttinger liquid (LL) behavior, a conductance T^alpha and a dynamic conductance V^alpha . We ... More
The Pioneer AnomalyJul 07 2008Analysis of the radio-metric data from Pioneer 10 and 11 spacecrafts has indicated the presence of an unmodeled acceleration starting at 20 AU, which has become known as the Pioneer anomaly. The nature of this acceleration is uncertain. In this paper ... More
Gravitational and electromagnetic signatures of accretion into a charged black holeDec 22 2016We present the derivation and the solutions to the coupled electromagnetic and gravitational perturbations with sources in a charged black hole background. We work in the so called ghost gauge and consider as source of the perturbations the infall of ... More
Variable Eddington Factor and Radiating Slowly Rotating Bodies in General RelativityMar 20 2005Aug 05 2006We present an extension to a previous work to study the collapse of a radiating, slow-rotating self-gravitating relativistic configuration. In order to simulate dissipation effects due to the transfer of photons and/or neutrinos within the matter configuration, ... More
NScale: Neighborhood-centric Large-Scale Graph Analytics in the CloudMay 07 2014Sep 30 2015There is an increasing interest in executing complex analyses over large graphs, many of which require processing a large number of multi-hop neighborhoods or subgraphs. Examples include ego network analysis, motif counting, personalized recommendations, ... More
Strong Baselines for Simple Question Answering over Knowledge Graphs with and without Neural NetworksDec 05 2017Jun 05 2018We examine the problem of question answering over knowledge graphs, focusing on simple questions that can be answered by the lookup of a single fact. Adopting a straightforward decomposition of the problem into entity detection, entity linking, relation ... More
Dynamic Memory Allocation Policies for Postings in Real-Time Twitter SearchFeb 21 2013We explore a real-time Twitter search application where tweets are arriving at a rate of several thousands per second. Real-time search demands that they be indexed and searchable immediately, which leads to a number of implementation challenges. In this ... More
New results on cut-off effects in spectroscopy with the fixed point actionNov 24 2004Dec 21 2004Our study on the cut-off effects in quenched light hadron spectroscopy and pion scattering length with the fixed point action is extended by results obtained at a lattice spacing a=0.102 fm in a box of size L=1.8 fm. The cut-off effects are small, but ... More
Bayesian learning of weakly structural Markov graph laws using sequential Monte Carlo methodsMay 31 2018Jul 23 2019We present a sequential sampling methodology for weakly structural Markov laws, arising naturally in a Bayesian structure learning context for decomposable graphical models. As a key component of our suggested approach, we show that the problem of graph ... More
JavaScript Convolutional Neural Networks for Keyword Spotting in the Browser: An Experimental AnalysisOct 30 2018Used for simple commands recognition on devices from smart routers to mobile phones, keyword spotting systems are everywhere. Ubiquitous as well are web applications, which have grown in popularity and complexity over the last decade with significant ... More
On the auxiliary particle filterSep 21 2007In this article we study asymptotic properties of weighted samples produced by the auxiliary particle filter (APF) proposed by pitt and shephard (1999). Besides establishing a central limit theorem (CLT) for smoothed particle estimates, we also derive ... More
Ginzburg-Landau Expansion in Non-Fermi Liquid Superconductors: Effect of the Mass Renormalization FactorAug 08 2002We reconsider the Ginzburg-Landau expansion for the case of a non-Fermi liquid superconductor. We obtain analytical results for the Ginzburg-Landau functional in the critical region around the superconducting phase transition, T <= T_c, in two special ... More
An extension theory for partial groups and localitiesJul 15 2015Sep 02 2015A partial group is a generalization of the concept of group recently introduced by A. Chermak. By considering partial groups as simplicial sets, we propose an extension theory for partial groups using the concept of (simplicial) fibre bundle. This way, ... More
Heavy quarkonia description from an energy dependent quark-antiquark potentialJan 11 2013Jul 09 2015We model the spectral effect of open flavor meson-meson thresholds in heavy quarkonia. The proposed energy dependent quark-antiquark static potential tries to incorporate in a quark model scheme the results from unquenched lattice calculations. A good ... More
On the Bohnenblust-Hille inequality and a variant of Littlewood's 4/3 inequalityMar 14 2012Oct 01 2012The search for sharp constants for inequalities of the type Littlewood's 4/3 and Bohnenblust-Hille, besides its pure mathematical interest, has shown unexpected applications in many different fields, such as Analytic Number Theory, Quantum Information ... More
Cosmological nonlinear structure formation in full general relativitySep 28 2014Nov 26 2014We perform numerical evolutions of cosmological scenarios using a standard general relativistic code in spherical symmetry. We concentrate on two different situations: initial matter distributions that are homogeneous and isotropic, and perturbations ... More
Cracking and instability of isotropic and anisotropic relativistic spheresOct 28 2014Using the concept of cracking, we have explored the influence of density fluctuations on the stability of isotropic and anisotropic matter configurations in General Relativity with "barotropic" equations of state, $P = P(\rho)$ and $P_{\perp}= P_{\perp}(\rho)$. ... More
HD 65949: The Highest Known Mercury Excess Of Any CP Star?Jun 29 2006ESO spectra of HD 65949 show it to be unlike any of the well-known types within its temperature range $\approx$ 13600K. It is neither a silicon, nor a mercury-manganese star, though it has a huge Hg II line at $\lambda$3984. We estimate $\log({\rm Hg/H}) ... More
Cracking isotropic and anisotropic relativistic spheresOct 28 2014Nov 15 2016We explore the influence of density fluctuations on isotropic and anisotropic configurations, extending the concept of cracking for general relativistic fluid spheres. This concept, conceived to describe the behaviour of anisotropic matter distributions ... More
Relation between Poisson and Schrödinger equation in one dimensionDec 08 2011Sep 21 2012The relation between the Poisson and Schr\"odinger equation in one dimension is obtained through a simple transformation. It is pointed out that this analogy between both equations can be only applied for potentials that involve a combination of attractive ... More
The Chemical Compositions of Stars with Planets: A ReviewSep 29 2006A number of trends among the properties of exoplanets have become evident in the years since the first one was announced in 1995. One particularly interesting trend began to emerge in 1997 -- the incidence of giant planets correlates with the metallicity ... More
Confining and repulsive potentials from effective non-Abelian gauge fields in graphene bilayersSep 16 2016We investigate the effect of shear and strain in graphene bilayers, under conditions where the distortion of the lattice gives rise to a smooth one-dimensional modulation in the stacking sequence of the bilayer. We show that strain and shear produce characteristic ... More
Generalized screened potential modelJun 19 2014A new non relativistic quark model to calculate the spectrum of heavy quark mesons is developed. The model is based on an interquark potential interaction that implicitly incorporates screening effects from meson-meson configurations. An analysis of the ... More
Long-distance behavior of the quark-antiquark static potential. Application to light-quark mesons and heavy quarkoniaSep 07 2009Screening effects from sea pairs on the quark-antiquark static potential are analyzed phenomenologically from the light-quark to the heavy-quark meson spectra. From the high excited light-quark meson spectrum a universal form for the screened static potential ... More
Symmetric topological complexity as the first obstruction in Goodwillie's Euclidean embedding tower for real projective spacesNov 05 2009Aug 27 2010As a first goal, it is explained why Goodwillie-Weiss calculus of embeddings offers new information about the Euclidean embedding dimension of P^m only for m < 16. Concrete scenarios are described in these low-dimensional cases, pinpointing where to look ... More
Mutagenesis and Background Neutron RadiationJun 25 2014Jun 27 2014We suggest a possible correlation between the ionization events caused by the background neutron radiation and the experimental data on mutations with damage in the DNA repair mechanism, coming from the Long Term Evolution Experiment in E. Coli populations. ... More
Mechanical interpretation of existence theorems in a nonlinear Dirichlet problemJan 29 1997The existence of radial solutions of a nonlinear Dirichlet problem in a ball is translated to the language of Mechanics, i.e. to requirements on the time of motion of a particle in an external potential and under the action of a viscosity force. This ... More
N electrons in a quantum dot: Two-point Pade approximantsNov 19 1996We present analytic estimates for the energy levels of N electrons (N = 2 - 5) in a two-dimensional parabolic quantum dot. A magnetic field is applied perpendicularly to the confinement plane. The relevant scaled energy is shown to be a smooth function ... More
Exact Partition Function for the Random Walk of an Electrostatic FieldAug 07 2016The partition function for the random walk of an electrostatic field produced by several static parallel infinite charged planes in which the charge distribution could be either $\pm\sigma$ is obtained. We find the electrostatic energy of the system and ... More
Variability Among Stars in the M 67 Field from Kepler/K2-Campaign-5 Light CurvesMar 21 2016We examine the photometric variability of stars in the M 67 field using Kepler/K2-Campaign-5 light curves. Variabilities and periods were determined for 639 stars. The mean photometric period of 28 single Sun-like members stars in M 67 is 23.4 +/- 1.2 ... More
Dynamics of small perturbations against a stationary polariton distributionOct 06 2008May 05 2009The dynamics of small perturbations against the stationary density matrix of a pumped polariton system with only one photon polarization is studied. Depending on the way the system is pumped and probed, decay times ranging from 30 to 5000 ps are found. ... More
The effect of trap anharmonicity on the critical temperature for Bose-Einstein condensationDec 24 2003The anharmonicity of a magnetic atomic trap at long distances from its center (forty times the radius of the first atomic orbit along the elongated axis, i.e. hundreds of microns) is shown to increase up to 45 % the temperature for Bose-Einstein condensation. ... More
Modular Curves Of Genus 2May 28 2001We prove that there is only a finite number of genus 2 curves C defined over Q such that there exists a nonconstant morphism pi:X_1(N) --->C defined over Q and the jacobian of C, J(C), is a Q-factor of the new part of the jacobian of X_1(N), J_1(N)^{new}. ... More
Trends in Processor ArchitectureJan 16 2018This paper presents an overview of the main trends in processor architecture. It starts with an analysis of the past evolution of processors and the main driving forces behind it, and then it focuses on a description of the main architectural features ... More
Large-scale tidal fields on primordial density perturbations ?Feb 17 1997We calculate the strength of the tidal field produced by the large-scale density field acting on primordial density perturbations in power law models. By analysing changes in the orientation of the deformation tensor, resulted from smoothing the density ... More
Tidal Shear on Density Perturbations and Galaxy FormationJun 05 1995The strenth of the tidal shear produced by the large-scale density field acting on primordial density perturbations is calculated in power law models. It is shown that the large-scale tidal field could, strongly affect the morphology, orientation and ... More
Limiting noises in gravitational wave detectors: guidance from their statistical propertiesApr 29 2003It is expected that interferometric gravitational wave detectors such as LIGO \cite{Barish99} will be eventually limited by fundamental noise sources like shot noise and Brownian motion, as well as by seismic noise. In the commissioning process, other ... More
On the numbers and division rates of stem cells in human tissuesAug 08 2017Both the fraction of stem over differentiated cell numbers, $N_s$ / $N_d$, and the cell division rate, $m_s$, experience relatively large variations (three decades) when different human tissues are considered. However, in a two-dimensional plot points ... More
The long-tail distribution function of mutations in bacteriaJul 24 2015Levy flights in the space of mutations model time evolution of bacterial DNA. Parameters in the model are adjusted in order to fit observations coming from the Long Time Evolution Experiment with E. Coli.
Estimating the number of tissue resident macrophagesMar 28 2016I provide a simple estimation for the number of macrophages in a tissue, arising from the hypothesis that they should keep infections below a certain threshold, above which neutrophils are recruited from blood circulation. The estimation reads Nm=a Ncel^{\alpha}/Nmax, ... More
Jet Physics at HERANov 26 2002Analyses of jet production at HERA have become precise enough to perform QCD studies which are both competitive and complementary to those at e+e- and p-pbar colliders. This report summarises some of the latest results on jet physics from the H1 and ZEUS ... More
Classifying semi-free Hamiltonian $S^1$-manifoldsFeb 16 2005May 10 2010In this paper we describe a method to establish when a symplectic manifold $M$ with semi-free Hamiltonian $S^{1}$-action is unique up to isomorphism (equivariant symplectomorphism). This will rely on a study of the symplectic topology of the reduced spaces. ... More
NEWS: the near-infrared Echelle for wideband spectroscopySep 22 2016We present an updated optical and mechanical design of NEWS: the Near-infrared Echelle for Wide-band Spectroscopy (formerly called HiJaK: the High-resolution J, H and K spectrometer), a compact, high-resolution, near-infrared spectrometer for 5-meter ... More
Properties of optimizers of the principal eigenvalue with indefinite weight and Robin conditionsMay 20 2016Nov 14 2016In this paper, we are interested in the analysis of a well-known free boundary/shape optimization problem motivated by some issues arising in population dynamics. The question is to determine optimal spatial arrangements of favorable and unfavorable regions ... More
Regularity for the optimal compliance problem with length penalizationDec 30 2015Apr 15 2016We prove some regularity results for a connected set S in the planar domain O, which minimizes the compliance of its complement O\S, plus its length. This problem, interpreted as to find the best location for attaching a membrane subject to a given external ... More
Fast Data in the Era of Big Data: Twitter's Real-Time Related Query Suggestion ArchitectureOct 27 2012We present the architecture behind Twitter's real-time related query suggestion and spelling correction service. Although these tasks have received much attention in the web search literature, the Twitter context introduces a real-time "twist": after ... More
Document Expansion by Query PredictionApr 17 2019One technique to improve the retrieval effectiveness of a search engine is to expand documents with terms that are related or representative of the documents' content. From the perspective of a question answering system, a useful representation of a document ... More
Sapphire: Querying RDF Data Made SimpleMay 29 2018Sep 13 2018RDF data in the linked open data (LOD) cloud is very valuable for many different applications. In order to unlock the full value of this data, users should be able to issue complex queries on the RDF datasets in the LOD cloud. SPARQL can express such ... More
Multi-Perspective Relevance Matching with Hierarchical ConvNets for Social Media SearchMay 21 2018Jun 22 2019Despite substantial interest in applications of neural networks to information retrieval, neural ranking models have only been applied to standard ad hoc retrieval tasks over web pages and newswire documents. This paper proposes MP-HCNN (Multi-Perspective ... More
An Experimental Analysis of the Power Consumption of Convolutional Neural Networks for Keyword SpottingOct 30 2017Sep 21 2018Nearly all previous work on small-footprint keyword spotting with neural networks quantify model footprint in terms of the number of parameters and multiply operations for a feedforward inference pass. These values are, however, proxy measures since empirical ... More
Identifying Duplicate and Contradictory Information in WikipediaJun 04 2014Our study identifies sentences in Wikipedia articles that are either identical or highly similar by applying techniques for near-duplicate detection of web pages. This is accomplished with a MapReduce implementation of minhash to identify clusters of ... More
An Unsupervised Feature Learning Approach to Improve Automatic Incident DetectionOct 29 2013Sophisticated automatic incident detection (AID) technology plays a key role in contemporary transportation systems. Though many papers were devoted to study incident classification algorithms, few study investigated how to enhance feature representation ... More
Optimal Control Theory in Intelligent Transportation Systems Research - A ReviewApr 13 2013Continuous motorization and urbanization around the globe leads to an expansion of population in major cities. Therefore, ever-growing pressure imposed on the existing mass transit systems calls for a better technology, Intelligent Transportation Systems ... More
Flipout: Efficient Pseudo-Independent Weight Perturbations on Mini-BatchesMar 12 2018Apr 02 2018Stochastic neural net weights are used in a variety of contexts, including regularization, Bayesian neural nets, exploration in reinforcement learning, and evolution strategies. Unfortunately, due to the large number of weights, all the examples in a ... More
Neural Graph Evolution: Towards Efficient Automatic Robot DesignJun 12 2019Despite the recent successes in robotic locomotion control, the design of robot relies heavily on human engineering. Automatic robot design has been a long studied subject, but the recent progress has been slowed due to the large combinatorial search ... More
The Unified Logging Infrastructure for Data Analytics at TwitterAug 21 2012In recent years, there has been a substantial amount of work on large-scale data analytics using Hadoop-based platforms running on large clusters of commodity machines. A less-explored topic is how those data, dominated by application logs, are collected ... More
Critically Examining the "Neural Hype": Weak Baselines and the Additivity of Effectiveness Gains from Neural Ranking ModelsApr 19 2019Is neural IR mostly hype? In a recent SIGIR Forum article, Lin expressed skepticism that neural ranking models were actually improving ad hoc retrieval effectiveness in limited data scenarios. He provided anecdotal evidence that authors of neural IR papers ... More
Matching Entities Across Different Knowledge Graphs with Graph EmbeddingsMar 15 2019This paper explores the problem of matching entities across different knowledge graphs. Given a query entity in one knowledge graph, we wish to find the corresponding real-world entity in another knowledge graph. We formalize this problem and present ... More
The Effects of Latency Penalties in Evaluating Push Notification SystemsJun 09 2016We examine the effects of different latency penalties in the evaluation of push notification systems, as operationalized in the TREC 2015 Microblog track evaluation. The purpose of this study is to inform the design of metrics for the TREC 2016 Real-Time ... More
Temperature dependent surface relaxation for Al(110) and Mg(10-10) studied by orbital free ab initio molecular dynamicsJun 06 2006We have performed orbital free ab initio molecular dynamics simulations in order to study the thermal behaviour of two open surfaces of solid metallic systems, namely the (110) face of fcc Al and the (10-10) face of hcp Mg. Our results reproduce qualitatively ... More
A study of the electronic properties of liquid alkali metals. A self--consistent approachAug 06 2002We study the electronic properties (density of states, conductivity and thermopower) of some nearly--free--electron systems: the liquid alkali metals and two liquid alloys, Li-Na and Na-K. The study has been performed within the self-consistent second ... More
Ab initio study of the atomic motion in liquid metal surfaces: comparison with Lennard-Jones systemsJun 07 2006It is established that liquid metals exhibit surface layering at the liquid-vapor interface, while dielectric simple systems, like those interacting through Lennard-Jones potentials, show a monotonic decay from the liquid density to that of the vapor. ... More
An indicator of journal impact that is based on calculating a journal's percentage of highly cited publicationsOct 13 2015The two most used citation impact indicators in the assessment of scientific journals are, nowadays, the impact factor and the h-index. However, both indicators are not field normalized (vary heavily depending on the scientific category) which makes them ... More
Vortex-antivortex pairs induced by curvatureOct 13 2016We show that the curvature of nanomagnets can be used to induce chiral textures in the magnetization field. Among the phenomena related to the interplay between geometry and magnetic behavior at nanomagnets, an effective curvature-induced Dzyaloshinskii-Moriya ... More
Pressure effects in the triangular layered cobaltites NaxCoO2Oct 23 2007We have measured transport properties as a function of temperature and pressure up to 30GPa in the NaxCoO2 system. For the x=0.5 sample the transition temperature at 53K increases with pressure, while paradoxically the sample passes from an insulating ... More
On the security defects of an image encryption schemeOct 08 2016This paper studies the security of a recently-proposed chaos-based image encryption scheme, and points out the following problems: 1) there exist a number of invalid keys and weak keys, and some keys are partially equivalent for encryption/decryption; ... More
Coulomb screening and electronic instabilities of small-diameter (5,0) nanotubesJun 24 2005Jul 15 2005We investigate the instabilities that may lead to the breakdown of the Luttinger liquid in the small-diameter (5,0) nanotubes, paying attention to the competition between the effective interaction mediated by phonon-exchange and the Coulomb interaction. ... More
Electronic instabilities in 3D arrays of small-diameter (3,3) carbon nanotubesOct 21 2005We investigate the electronic instabilities of the small-diameter (3,3) carbon nanotubes by studying the low-energy perturbations of the normal Luttinger liquid regime. The bosonization approach is adopted to deal exactly with the interactions in the ... More
On the Nature of Nonperturbative Effects in Stabilized 2D Quantum GravitySep 27 1993We remark that the weak coupling regime of the stochastic stabilization of 2D quantum gravity has a unique perturbative vacuum, which does not support instanton configurations. By means of Monte Carlo simulations we show that the nonperturbative vacuum ... More
Belokurov-Usyukina loop reduction in non-integer dimensionJun 21 2012Belokurov-Usyukina loop reduction method has been proposed in 1983 to reduce a number of rungs in triangle ladder-like diagram by one. The disadvantage of the method is that it works in d=4 dimensions only and it cannot be used for calculation of amplitudes ... More
Parent Stars of Extrasolar Planets. VIII. Chemical Abundances for 18 Elements in 31 StarsApr 17 2007We present the results of detailed spectroscopic abundance analyses for 18 elements in 31 nearby stars with planets. The resulting abundances are combined with other similar studies of nearby stars with planets and compared to a sample of nearby stars ... More
A Re-evaluation of the Super Li-rich Star in NGC 6633Jun 09 2003We present a new abundance analysis of the super Li-rich star J37 and a comparison star in NGC 6633. We confirm the result of Deliyannis et al. that J37 has a Li abundance well above the meteoritic value, and we also confirm that Al, S, Si, Ca, Fe and ... More