Results for "Phil Kopel"

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Regularity Conditions for Convergence of Linear Statistics of GUEOct 10 2015Oct 13 2015We establish a central limit theorem for the unnormalized linear statistic of the Gaussian Unitary Ensemble under optimal conditions: the linear statistics converges if and only if the expression for the limiting variance is finite.
Linear Statistics of Non-Hermitian Matrices Matching the Real or Complex Ginibre Ensemble to Four MomentsOct 10 2015We prove that, for general test functions, the limiting behavior of the linear statistic of an independent entry random matrix is determined only by the first four moments of the entry distributions. This immediately generalizes the known central limit ... More
Random matrix products: Universality and least singular valuesFeb 08 2018We establish local universality of the $k$-point correlation functions associated with products of independent iid random matrices, as the sizes of the matrices tend to infinity, under a moment matching hypothesis. We also prove Gaussian limits for the ... More
NP in BQP with NonlinearityApr 09 1998Apr 27 1998If one modifies the laws of Quantum Mechanics to allow nonlinear evolution of quantum states, this paper shows that NP-complete problems would be efficiently solvable in polynomial time with bounded probability (NP in BQP). With that (admittedly very ... More
Quantum Statistical Mechanics as an Exact Classical Expansion with Results for Lennard-Jones HeliumSep 26 2016Nov 01 2016The quantum states representing classical phase space are given, and these are used to formulate quantum statistical mechanics as a formally exact double perturbation expansion about classical statistical mechanics. One series of quantum contributions ... More
Thermodynamic Stability of NanobubblesMar 15 2015The observed stability of nanobubbles contradicts the well-known result in classical nucleation theory, that the critical radius is both microscopic and thermodynamically unstable. Here nanoscopic stability is shown to be the combined result of two non-classical ... More
How to Measure Forces when the Atomic Force Microscope shows Non-Linear ComplianceDec 13 2012Jan 12 2013A spreadsheet algorithm is given for the atomic force microscope that accounts for non-linear behavior in the deflection of the cantilever and in the photo-diode response. In addition, the data analysis algorithm takes into account cantilever tilt, friction ... More
Quantum Statistical Mechanics. II. Stochastic Schrodinger EquationDec 18 2013Jun 02 2014The stochastic dissipative Schrodinger equation is derived for an open quantum system consisting of a sub-system able to exchange energy with a thermal reservoir. The resultant evolution of the wave function also gives the evolution of the density matrix, ... More
More Reliable Measurements of the Slip Length with the Atomic Force MicroscopeFeb 27 2013Mar 06 2013Further improvements are made to the non-linear data analysis algorithm for the atomic force microscope [P. Attard, arXiv:1212.3019v2 (2012)]. The algorithm is required when there is curvature in the compliance region due to photo-diode non-linearity. ... More
Design of Chemotaxis Devices Using Nano-MotorsSep 07 2012Several designs for micro-devices for chemotaxis based on nano-motors are proposed. The nano- or micro-motors are the conventional Janus rods or spheres that are powered by the catalytic reaction of fuels such as hydrogen peroxide. It is shown how these ... More
Quantum Statistical Mechanics as an Exact Classical Expansion with Results for Lennard-Jones HeliumSep 26 2016Oct 11 2016The quantum states representing classical phase space are given, and these are used to formulate quantum statistical mechanics as a formally exact double perturbation expansion about classical statistical mechanics. One series of quantum contributions ... More
Physical component analysis of galaxy cluster weak gravitational lensing dataNov 09 2005Oct 30 2007We present a novel approach for reconstructing the projected mass distribution of clusters of galaxies from sparse and noisy weak gravitational lensing shear data. The reconstructions are regularised using knowledge gained from numerical simulations of ... More
Direct Measurement of the Surface Tension of NanobubblesMay 09 2015It is shown that when the nanobubble contact line is pinned to a penetrating tip the interface behaves like a Hookean spring with spring constant proportional to the nanobubble surface tension. Atomic force microscope (AFM) data for several nanobubbles ... More
Quantum Statistical Mechanics. I. Decoherence, Wave Function Collapse, and the von Neumann Density MatrixNov 25 2013The probability operator is derived from first principles for an equilibrium quantum system. It is also shown that the superposition states collapse into a mixture of states giving the conventional von Neumann trace form for the quantum average. The mechanism ... More
Is the Information Entropy the Same as the Statistical Mechanical Entropy?Sep 25 2012It is shown that the standard expression for the information entropy, originally due to Shannon, is only valid for a particular set of states. For the general case of statistical mechanics, one needs to include an additional term in the expression for ... More
Thermodynamics for Non-equilibrium Pattern FormationFeb 10 2011Sep 10 2012The second entropy theory for non-equilibrium thermodynamics is used to show that the optimum structure or pattern of a time-dependent system corresponds to the maximum entropy. A formula for the total entropy of convective heat flow is derived. The Navier-Stokes ... More
BADREX: In situ expansion and coreference of biomedical abbreviations using dynamic regular expressionsJun 20 2012BADREX uses dynamically generated regular expressions to annotate term definition-term abbreviation pairs, and corefers unpaired acronyms and abbreviations back to their initial definition in the text. Against the Medstract corpus BADREX achieves precision ... More
Networks Unplugged: Towards A Model of Compatibility Regulation Between Information PlatformsSep 24 2001Networks Unplugged: Towards A Model of Compatibility Regulation Between Information Platforms This Article outlines a basic model for regulating interoperability between rival information platforms. In so doing, it insists that antitrust, intellectual ... More
Fermionic Vector Model Solitons in the Large N LimitMay 12 2005May 31 2005The large N limit of fermionic vectors models is studied using bilocal variables, in the framework of a collective field theory approach. The large N configuration is determined completely using only classical solutions of the model. Further, the Bethe-Salpeter ... More
Quantum Statistical Mechanics. IV. Non-Equilibrium Probability Operator and Stochastic, Dissipative Schrodinger EquationJun 20 2014Jun 23 2014The probability operator for a generic non-equilibrium quantum system is derived. The corresponding stochastic, dissipative Schr\"odinger equation is also given. The dissipative and stochastic propagators are linked by the fluctuation-dissipation theorem ... More
Quantum Statistical Mechanics. III. Equilibrium ProbabilityApr 10 2014Given are a first principles derivation and formulation of the probabilistic concepts that underly equilibrium quantum statistical mechanics. The transition to non-equilibrium probability is traversed briefly.
Simplified Derivation of the Non-Equilibrium Probability DistributionMay 06 2014A simple and transparent derivation of the formally exact probability distribution for classical non-equilibrium systems is given. The corresponding stochastic, dissipative equations of motion are also derived.
Expansion for Quantum Statistical Mechanics Based on Wave Function SymmetrizationMar 22 2016May 11 2016An expansion for quantum statistical mechanics is derived that gives classical statistical mechanics as the leading term. Each quantum correction comes from successively larger permutation loops, which arise from the factorization of the symmetrization ... More
Optimising Principle for Non-Equilibrium Phase Transitions and Pattern Formation with Results for Heat ConvectionAug 25 2012Spontaneous transitions between non-equilibrium patterns are characterised by hydrodynamic calculations of ideal straight roll steady state heat convection. The calculations are tested quantitatively against existing experimental data. It is shown that ... More
Quantum Statistical Mechanics in Classical Phase Space. III. Mean Field Approximation Benchmarked for Interacting Lennard-Jones ParticlesDec 10 2018A Monte Carlo computer simulation algorithm in classical phase space is given for the treatment of quantum systems. The non-commutativity of position and momentum is accounted for by a mean field approach and instantaneous effective harmonic oscillators. ... More
Quantum Statistical Mechanics as an Exact Classical Expansion with Results for Lennard-Jones HeliumSep 26 2016The quantum states representing classical phase space are given, and these are used to formulate quantum statistical mechanics as a formally exact double perturbation expansion about classical statistical mechanics. One series of quantum contributions ... More
Quantum Carry-Save ArithmeticAug 27 1998Aug 30 1998This paper shows how to design efficient arithmetic elements out of quantum gates using "carry-save" techniques borrowed from classical computer design. This allows bit-parallel evaluation of all the arithmetic elements required for Shor's algorithm, ... More
Using administrative data to improve the estimation of immigration to local areas in EnglandMar 03 2009Aug 24 2009International migration is now a significant driver of population change across Europe but the methods available to estimate its true impact upon sub-national areas remain inconsistent, constrained by inadequate systems of measurement and data capture. ... More
Spectroscopic Binaries in Globular Clusters. I. A Search for Ultra-Hard Binaries on the Main Sequence in M4May 02 1996A search for spectroscopic binaries on the main sequence of the nearby globular cluster M4 has been undertaken with Argus, the multi-object spectrograph on the CTIO 4.0m telescope. A pair of radial velocities (median precision $\simeq$ 2 km/s) separated ... More
Combined Reduced-Rank TransformApr 10 2006We propose and justify a new approach to constructing optimal nonlinear transforms of random vectors. We show that the proposed transform improves such characteristics of rank-reduced transforms as compression ratio, accuracy of decompression and reduces ... More
Event-Symmetric PhysicsMay 16 1995I examine various aspects of event-symmetric physics such as phase changes, symmetry breaking and duality by studying a number of simple toy-models.
The Degrees of Freedom of Compute-and-ForwardJan 11 2011Apr 20 2012We analyze the asymptotic behavior of compute-and-forward relay networks in the regime of high signal-to-noise ratios. We consider a section of such a network consisting of K transmitters and K relays. The aim of the relays is to reliably decode an invertible ... More
Language as a Latent Variable: Discrete Generative Models for Sentence CompressionSep 23 2016Oct 14 2016In this work we explore deep generative models of text in which the latent representation of a document is itself drawn from a discrete language model distribution. We formulate a variational auto-encoder for inference in this model and apply it to the ... More
Language as a Latent Variable: Discrete Generative Models for Sentence CompressionSep 23 2016In this work we explore deep generative models of text in which the latent representation of a document is itself drawn from a discrete language model distribution. We formulate a variational auto-encoder for inference in this model and apply it to the ... More
Stochastic Collapsed Variational Inference for Hidden Markov ModelsDec 05 2015Stochastic variational inference for collapsed models has recently been successfully applied to large scale topic modelling. In this paper, we propose a stochastic collapsed variational inference algorithm for hidden Markov models, in a sequential data ... More
Recurrent Convolutional Neural Networks for Discourse CompositionalityJun 15 2013The compositionality of meaning extends beyond the single sentence. Just as words combine to form the meaning of sentences, so do sentences combine to form the meaning of paragraphs, dialogues and general discourse. We introduce both a sentence model ... More
Canaries in a Coal Mine: Using Globular Clusters to Place Limits on Massive Black Holes in the Galactic HaloNov 23 1998We explore the possibility that massive black holes comprise a significant fraction of the dark matter of our galaxy by studying the dissolution of galactic globular clusters bombarded by them. In our simulations, we evolve the clusters along a sequence ... More
The Small Scale Structure of Space-Time: A Bibliographical ReviewJun 26 1995Jan 26 1996This essay is a tour around many of the lesser known pregeometric models of physics, as well as the mainstream approaches to quantum gravity, in search of common themes which may provide a glimpse of the final theory which must lie behind them.
Symmetry in the Topological Phase of String TheoryApr 28 1995Sep 22 1995I present arguments to the affect that the topological phase of string theory must be event-symmetric. This motivates a search for a universal string group for discrete strings in event-symmetric space-time which unifies space-time symmetry with internal ... More
Symmetric powers of elliptic curve L-functionsApr 05 2006Apr 17 2006The conjectures of Deligne, Be\u\i linson, and Bloch-Kato assert that there should be relations between the arithmetic of algebro-geometric objects and the special values of their $L$-functions. We make a numerical study for symmetric power $L$-functions ... More
Near Infrared Spectroscopy of the Ultracompact HII region G45.12+0.13Mar 21 1996We present complete, low resolution IJHK spectroscopy of the ultracompact HII region, G45.12+0.13. From the observed HI line strengths, we derive a near infrared extinction law that is slightly steeper than the average. After correction with this extinction ... More
Pragmatic Neural Language Modelling in Machine TranslationDec 22 2014Mar 20 2015This paper presents an in-depth investigation on integrating neural language models in translation systems. Scaling neural language models is a difficult task, but crucial for real-world applications. This paper evaluates the impact on end-to-end MT quality ... More
Fundamental Parameters of Low Mass X-ray Binaries II: X-Ray Persistent SystemsJun 24 2005The determination of fundamental parameters in X-ray luminous (persistent) X-ray binaries has been classically hampered by the large optical luminosity of the accretion disc. New methods, based on irradiation of the donor star and burst oscillations, ... More
Stochastic Collapsed Variational Inference for Sequential DataDec 05 2015Stochastic variational inference for collapsed models has recently been successfully applied to large scale topic modelling. In this paper, we propose a stochastic collapsed variational inference algorithm in the sequential data setting. Our algorithm ... More
A Bayesian Model for Generative Transition-based Dependency ParsingJun 13 2015Jun 28 2015We propose a simple, scalable, fully generative model for transition-based dependency parsing with high accuracy. The model, parameterized by Hierarchical Pitman-Yor Processes, overcomes the limitations of previous generative models by allowing fast and ... More
Response to "Concerning Thermal Tides on Hot Jupiters" (Goodman 2009; arXiv: 0901.3279)Dec 11 2009Dec 11 2009Motivated by the comments of Goodman (2009) on our paper concerning thermal tides (Arras and Socrates 2009a), we have studied an idealized problem to understand the global response of a completely fluid gas giant planet to thermal forcing at the surface ... More
Thermal Tides in Fluid Extrasolar PlanetsDec 11 2009Asynchronous rotation and orbital eccentricity lead to time-dependent irradiation of the close-in gas giant exoplanets -- the hot Jupiters. This time-dependent surface heating gives rise to fluid motions which propagate throughout the planet. We investigate ... More
A Review of Procedure to Evolve Quantum ProceduresAug 24 2007There exist quantum algorithms that are more efficient than their classical counterparts; such algorithms were invented by Shor in 1994 and then Grover in 1996. A lack of invention since Grover's algorithm has been commonly attributed to the non-intuitive ... More
Is String Theory in Knots?Oct 09 1995It is sometimes said that there may be a unique algebraic theory independent of space-time topologies which underlies superstring and p-brane theories. In this paper, I construct some algebras using knot relations within the framework of event-symmetric ... More
Multiplicity of the trivial representation in rank-selected homology of the partition latticeNov 16 2003We study the multiplicity $b_S(n)$ of the trivial representation in the symmetric group representations $\beta_S$ on the (top) homology of the rank-selected partition lattice $\Pi_n^S$. We break the possible rank sets $S$ into three cases: (1) $1\not\in ... More
A high resolution comparative study of the slowly contracting, starless cores, L694-2 and L1544Sep 17 2005Sep 20 2005We present interferometric observations of N2H+(1-0) in the starless, dense core L694-2 and compare them to previously published maps of L1544. Both cores are starless, centrally condensed, and show spectral signatures of rotation and collapse. We fit ... More
Boundaries of univalent Baker domainsNov 25 2014Let $f$ be a transcendental entire function and let $U$ be a univalent Baker domain of $f$. We prove a new result about the boundary behaviour of conformal maps and use this to show that the non-escaping boundary points of $U$ form a set of harmonic measure ... More
Thermal Tides in Short Period ExoplanetsJan 07 2009Time-dependent insolation in a planetary atmosphere induces a mass quadrupole upon which the stellar tidal acceleration can exert a force. This "thermal tide" force can give rise to secular torques on the planet and orbit as well as radial forces causing ... More
Regional Development in the Knowledge-Based Economy: The Construction of AdvantageNov 17 2009In this introduction the editors showcase the papers by way of a structured project and seek to clarify the two key concepts cited in the title. We consider the history of the idea that knowledge is an economic factor, and discuss the question of whether ... More
A Search for Wolf-Rayet Stars in the Small Magellanic CloudOct 20 2000Nov 27 2000We conducted an extensive search for Wolf-Rayet stars (W-Rs) in the SMC, using the same interference filter imaging techniques that have proved successful in finding W-Rs in more distant members of the Local Group. Photometry of some 1.6 million stellar ... More
String Partons and Multiple QuantisationSep 16 1996I consider an algebraic construction of creation and annihilation operators for superstring and p-brane parton models. The result can be interpreted as a realisation of multiple quantisation and suggests a relationship between quantisation and dimension. ... More
A Hodge decomposition for the complex of injective wordsNov 16 2003Reiner and Webb compute the $S_n$-module structure for the complex of injective words in [RW]. This paper refines their formula by providing a Hodge type decomposition. Along the way, this paper proves that the simplicial boundary map interacts in a nice ... More
Thermal Structure and Radius Evolution of Irradiated Gas Giant PlanetsJan 15 2006We consider the thermal structure and radii of strongly irradiated gas giant planets over a range in mass and irradiating flux. The cooling rate of the planet is sensitive to the surface boundary condition, which depends on the detailed manner in which ... More
Can Parity Violation in Neutrino Transport Lead to Pulsar Kicks?Jun 21 1998In magnetized proto-neutron stars, neutrino cross sections depend asymmetrically on the neutrino momenta due to parity violation. However, these asymmetric opacities do not induce any asymmetric flux in the bulk interior of the star where neutrinos are ... More
Is the Universe Uniquely Determined by Invariance Under Quantisation?Mar 25 1996In this sequel to my previous paper, "Is String Theory in Knots?" I explore ways of constructing symmetries through an algebraic stepping process using knotted graphs. The hope is that this may lead to an algebraic formulation of string theory. In the ... More
Neutrino-Nucleon Interactions in Magnetized Neutron-Star Matter: The Effects of Parity ViolationNov 24 1998We study neutrino-nucleon scattering and absorption in a dense, magnetized nuclear medium. These are the most important sources of neutrino opacity governing the cooling of a proto-neutron star in the first tens of seconds after its formation. Because ... More
Modelling the Lexicon in Unsupervised Part of Speech InductionFeb 26 2014Automatically inducing the syntactic part-of-speech categories for words in text is a fundamental task in Computational Linguistics. While the performance of unsupervised tagging models has been slowly improving, current state-of-the-art systems make ... More
Multi-Wavelength Variability. Accretion and Ejection at the Fastest TimescalesJan 09 2015Multiwavelength variability data, combined with spectral-timing analysis techniques, provides information about the causal relationship between different physical components in accreting black holes. Using fast-timing data and long-term monitoring, we ... More
Extent of hydrogen coverage of Si(001) under chemical vapor deposition conditions from ab initio approachesMar 09 2016Mar 10 2016The extent of hydrogen coverage of the Si(001)c(4x2) surface in the presence of hydrogen gas has been studied with dispersion corrected density functional theory. Electronic energy contributions are well described using a hybrid functional. The temperature ... More
Cues and control in Expert-Client DialoguesApr 05 1995We conducted an empirical analysis into the relation between control and discourse structure. We applied control criteria to four dialogues and identified 3 levels of discourse structure. We investigated the mechanism for changing control between these ... More
Global Asymptotics of the Second Painlevé Equation in Okamoto's SpaceDec 08 2012We study the solutions of the second Painlev\'e equation in the space of initial conditions first constructed by Okamoto, in the limit as the independent variable, x, goes to infinity. Simultaneously, we study solutions of the related equation known as ... More
Higgsless W Unitarity from Decoupling DeconstructionJun 25 2004Aug 11 2004Recently there has been interest in electroweak models on a five dimensional interval that break the symmetry without a higgs boson. By warping the metric of the interval it may be possible to avoid experimental bounds on extra W bosons and delta rho. ... More
Poincaré Invariant Quantum Mechanics based on Euclidean Green functionsAug 31 2010We investigate a formulation of Poincar\'e invariant quantum mechanics where the dynamical input is Euclidean invariant Green functions or their generating functional. We argue that within this framework it is possible to calculate scattering observables, ... More
Phase-Resolved Spectroscopy of Type B Quasi-Periodic Oscillations in GX 339-4May 05 2016Jul 15 2016We present a new spectral-timing technique for phase-resolved spectroscopy and apply it to the low-frequency Type B quasi-periodic oscillation (QPO) from the black hole X-ray binary GX 339-4. We show that on the QPO time-scale the spectrum changes not ... More
Multilingual Models for Compositional Distributed SemanticsApr 17 2014We present a novel technique for learning semantic representations, which extends the distributional hypothesis to multilingual data and joint-space embeddings. Our models leverage parallel data and learn to strongly align the embeddings of semantically ... More
Global models of planetary system formation in radiatively-inefficient protoplanetary discsDec 13 2011(Abridged) We present the results of N-body simulations of planetary systems formation in radiatively-inefficient disc models, where positive corotation torques may counter the rapid inward migration of low mass planets driven by Lindblad torques. The ... More
Compositional Morphology for Word Representations and Language ModellingMay 16 2014This paper presents a scalable method for integrating compositional morphological representations into a vector-based probabilistic language model. Our approach is evaluated in the context of log-bilinear language models, rendered suitably efficient for ... More
Cartan's topological structureJan 30 2001A system of differential forms will establish a topology and a topological structure on a domain of independent variables such that is possible to determine which maps or processes acting on the system are continuous. Perhaps the most simple topology ... More
A Detailed Numerical Analysis of Asymmetrical Density Distribution in Saturn's F ring During an Encounter with PrometheusDec 20 2013Saturn's rings, reminiscent of an early Solar System present a unique opportunity to investigate experimentally some mechanisms thought to be responsible for planet and planetesimal formation in protoplanetary discs. Here we extended the comparison of ... More
The distribution of the non-prime numbers - A new SieveJan 19 2011We present a new sieve that allows us to find the prime numbers by using only regular patterns and, more importantly, avoiding any duplication of elements between them.
Prometheus Induced Vorticity In Saturns F RingSep 05 2016Saturns rings are known to show remarkable real time variability in their structure. Many of which can be associated to interactions with nearby moons and moonlets. Possibly the most interesting and dynamic place in the rings, probably in the whole Solar ... More
Multilingual Distributed Representations without Word AlignmentDec 20 2013Mar 20 2014Distributed representations of meaning are a natural way to encode covariance relationships between words and phrases in NLP. By overcoming data sparsity problems, as well as providing information about semantic relatedness which is not available in discrete ... More
On the Number of Iterations for Dantzig-Wolfe Optimization and Packing-Covering Approximation AlgorithmsMay 19 2002Nov 19 2015We give a lower bound on the iteration complexity of a natural class of Lagrangean-relaxation algorithms for approximately solving packing/covering linear programs. We show that, given an input with $m$ random 0/1-constraints on $n$ variables, with high ... More
Fundamental parameters of FR II radio galaxies and their impact on groups and clusters' environmentsOct 30 2012Radio galaxies are among the largest and most powerful single objects known and are found at variety of redshifts, hence they are believed to have had a significant impact on the evolving Universe. Their relativistic jets inject considerable amounts of ... More
Spectroscopic Constraints on the Stellar Population of Elliptical Galaxies in the Coma ClusterFeb 26 2000Near-IR spectra for a sample of 31 elliptical galaxies in the Coma cluster are obtained. The galaxies are selected to be ellipticals (no lenticulars), with a large spatial distribution, covering both the core and outskirt of the cluster (ie. corresponding ... More
Vacuum polarization for lukewarm black holesAug 28 2007Dec 20 2007We compute the renormalized expectation value of the square of a quantum scalar field on a Reissner-Nordstrom-de Sitter black hole in which the temperatures of the event and cosmological horizons are equal (`lukewarm' black hole). Our numerical calculations ... More
Axisymmetric Simulations of Hot Jupiter-Stellar Wind Hydrodynamic InteractionJan 20 2016Gas giant exoplanets orbiting at close distances to the parent star are subjected to large radiation and stellar wind fluxes. In this paper, hydrodynamic simulations of the planetary upper atmosphere and its interaction with the stellar wind are carried ... More
Timing the warm absorber in NGC 4051Jul 04 2016We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results on the extensive ~ 600 ks of XMM-Newton archival observations of the bright ... More
Electron-Vibron Coupling at Metal-Organic Interfaces from Theory and ExperimentMar 15 2015Feb 10 2016We study the significance and characteristics of interfacial dynamical charge transfer at metal-organic interfaces for the organic semiconductor model system 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) on Ag(111) quantitatively. We combine ... More
Discovery of kpc-scale line emission in barred galaxies, not linked to AGN or star formationApr 15 2015We present an analysis of the optical line emission from nearby barred galaxies, and in particular look at the radial range occupied by the bar. In many cases this region is marked by what we term a 'star formation desert', with a marked deficit of HII ... More
Virtualizing Lifemapper Software Infrastructure for Biodiversity ExpeditionSep 22 2015One of the activities of the Pacific Rim Applications and Grid Middleware Assembly (PRAGMA) is fostering Virtual Biodiversity Expeditions (VBEs) by bringing domain scientists and cyber infrastructure specialists together as a team. Over the past few years ... More
Bolometric Corrections for optical light curves of Core-collapse SupernovaeNov 08 2013Through the creation of spectral energy distributions for well-observed literature core-collapse supernovae (CCSNe), we present corrections to transform optical light curves to full bolometric light curves. These corrections take the form of parabolic ... More
Price Trackers Inspired by Immune MemoryApr 22 2010In this paper we outline initial concepts for an immune inspired algorithm to evaluate price time series data. The proposed solution evolves a short term pool of trackers dynamically through a process of proliferation and mutation, with each member attempting ... More
Online Segment to Segment Neural TransductionSep 26 2016We introduce an online neural sequence to sequence model that learns to alternate between encoding and decoding segments of the input as it is read. By independently tracking the encoding and decoding representations our algorithm permits exact polynomial ... More
On the Stability of the 421-day Periodicity in A0538-66Nov 01 2002In this paper we analyse 70 years of archival Harvard and Schmidt plate data of the 16.6 d Be X-ray binary A0538-66 in order to search for the presence of the long-term period of 420.82 +/- 0.79 d found in MACHO photometry (Alcock et al. 2001). We find ... More
WZ Sagittae as a DQ Herculis starJan 21 1999We argue that quiescent WZ Sge is a rapidly spinning magnetic rotator in which most of the matter transfered from the secondary is ejected from the system. Assuming that the observed 27.87 s oscillation period is due to the spinning white dwarf we propose ... More
A Free, Fast, Simple and Efficient TVD MHD CodeMay 06 2003We describe a numerical method to solve the magnetohydrodynamic (MHD) equations. The fluid variables are updated along each direction using the flux conservative, 2nd order, total variation diminishing (TVD), upwind scheme of Jin and Xin. The magnetic ... More
Continuity properties of transport coefficients in simple mapsJan 16 2008We consider families of dynamics that can be described in terms of Perron-Frobenius operators with exponential mixing properties. For piecewise C^2 expanding interval maps we rigorously prove continuity properties of the drift J(l) and of the diffusion ... More
A Convolutional Neural Network for Modelling SentencesApr 08 2014The ability to accurately represent sentences is central to language understanding. We describe a convolutional architecture dubbed the Dynamic Convolutional Neural Network (DCNN) that we adopt for the semantic modelling of sentences. The network uses ... More
Dynamics of Chromospheric Upflows and Underlying Magnetic FieldsMar 19 2013We used \ha-0.1 nm and magnetic field (at 1.56$\mu$) data obtained with the New Solar Telescope to study the origin of the disk counterparts to type II spicules, so-called rapid blueshifted excursions (RBEs). The high time cadence of our chromospheric ... More
The Stability of Massive Main Sequence Stars as a Function of MetallicityApr 20 2012We investigate the pulsational stability of massive (M >~ 120 Msun) main sequence stars of a range of metallicities, including primordial, Population III stars. We include a formulation of convective damping motivated by numerical simulations of the interaction ... More
Diffusive Nuclear Burning of Helium on Neutron StarsAug 11 2010Diffusive nuclear burning of H by an underlying material capable of capturing protons can readily consume H from the surface of neutron stars (NSs) during their early cooling history. In the absence of subsequent accretion, it will be depleted from the ... More
Optimizing Performance of Recurrent Neural Networks on GPUsApr 07 2016As recurrent neural networks become larger and deeper, training times for single networks are rising into weeks or even months. As such there is a significant incentive to improve the performance and scalability of these networks. While GPUs have become ... More
Quasi-Periodic Oscillations from Magnetorotational TurbulenceFeb 13 2006Quasi-periodic oscillations (QPOs) in the X-ray lightcurves of accreting neutron star and black hole binaries have been widely interpreted as being due to standing wave modes in accretion disks. These disks are thought to be highly turbulent due to the ... More
Magnetic Field Evolution in Neutron Star Crusts due to the Hall Effect and Ohmic DecayFeb 17 2004We present calculations of magnetic field evolution by the Hall effect and Ohmic decay in neutron star crusts. We first discuss when and for which neutron stars the Hall effect is important relative to Ohmic decay. We compute the evolution of an initial ... More