Results for "Andrew Anderson"

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Vectorization of Multibyte Floating Point Data FormatsJan 26 2016Jul 22 2016We propose a scheme for reduced-precision representation of floating point data on a continuum between IEEE-754 floating point types. Our scheme enables the use of lower precision formats for a reduction in storage space requirements and data transfer ... More
Developing Knowledge States: Technology and the Enhancement of National Statistical CapacityFeb 26 2015National statistical systems are the enterprises tasked with collecting, validating and reporting societal attributes. These data serve many purposes - they allow governments to improve services, economic actors to traverse markets, and academics to assess ... More
Curvature-based Gauge-Invariant Perturbation Theory for Gravity: A New ParadigmJan 20 1998A new approach to gravitational gauge-invariant perturbation theory begins from the fourth-order Einstein-Ricci system, a hyperbolic formulation of gravity for arbitrary lapse and shift whose centerpiece is a wave equation for curvature. In the Minkowski ... More
A Taxonomy of Channel Pruning Signals in CNNsJun 11 2019Convolutional neural networks (CNNs) are widely used for classification problems. However, they often require large amounts of computation and memory which are not readily available in resource constrained systems. Pruning unimportant parameters from ... More
Hamiltonian dynamics of two same-sign point vorticesDec 09 2015Apr 14 2016We have studied numerically the Hamiltonian dynamics of two same-sign point vortices in an effectively two-dimensional, harmonically trapped Bose-Einstein condensate. We have found in the phase space of the system an impenetrable wall that divides the ... More
Limitless HTTP in an HTTPS World: Inferring the Semantics of the HTTPS Protocol without DecryptionMay 29 2018We present new analytic techniques for inferring HTTP semantics from passive observations of HTTPS that can infer the value of important fields including the status-code, Content-Type, and Server, and the presence or absence of several additional HTTP ... More
Error Analysis and Improving the Accuracy of Winograd Convolution for Deep Neural NetworksMar 29 2018May 01 2019Popular deep neural networks (DNNs) spend the majority of their execution time computing convolutions. The Winograd family of algorithms can greatly reduce the number of arithmetic operations required and is present in many DNN software frameworks. However, ... More
How the Experts Do It: Assessing and Explaining Agent Behaviors in Real-Time Strategy GamesNov 19 2017How should an AI-based explanation system explain an agent's complex behavior to ordinary end users who have no background in AI? Answering this question is an active research area, for if an AI-based explanation system could effectively explain intelligent ... More
Scalar Arithmetic Multiple Data: Customizable Precision for Deep Neural NetworksSep 27 2018Quantization of weights and activations in Deep Neural Networks (DNNs) is a powerful technique for network compression, and has enjoyed significant attention and success. However, much of the inference-time benefit of quantization is accessible only through ... More
Laser powder-bed fusion additive manufacturing: physics of complex melt flow and formation mechanisms of pores, spatter and denudation zonesDec 08 2015Jan 05 2016This study demonstrates the significant effect of the recoil pressure and Marangoni convection in laser powder bed fusion (L-PBF) of 316L stainless steel. A three-dimensional high fidelity powder-scale model reveals how the strong dynamical melt flow ... More
The Romulus Cosmological Simulations: A Physical Approach to the Formation, Dynamics and Accretion Models of SMBHsJul 07 2016We present a novel implementation of supermassive black hole (SMBH) formation, dynamics, and accretion in the massively parallel tree+SPH code, ChaNGa. This approach improves the modeling of SMBHs in fully cosmological simulations, allowing for a more ... More
The Romulus Cosmological Simulations: A Physical Approach to the Formation, Dynamics and Accretion Models of SMBHsJul 07 2016Jun 27 2017We present a novel implementation of supermassive black hole (SMBH) formation, dynamics, and accretion in the massively parallel tree+SPH code, ChaNGa. This approach improves the modeling of SMBHs in fully cosmological simulations, allowing for a more ... More
Toward Foraging for Understanding of StarCraft Agents: An Empirical StudyNov 21 2017Dec 26 2017Assessing and understanding intelligent agents is a difficult task for users that lack an AI background. A relatively new area, called "Explainable AI," is emerging to help address this problem, but little is known about how users would forage through ... More
Explaining Reinforcement Learning to Mere Mortals: An Empirical StudyMar 22 2019Jun 18 2019We present a user study to investigate the impact of explanations on non-experts' understanding of reinforcement learning (RL) agents. We investigate both a common RL visualization, saliency maps (the focus of attention), and a more recent explanation ... More
Using negative-latency gravitational wave alerts to detect prompt radio bursts from binary neutron star mergers with the Murchison Widefield ArrayAug 23 2019We examine how fast radio burst (FRB)-like signals predicted to be generated during the merger of a binary neutron star (BNS) may be detected in low-frequency radio observations triggered by the aLIGO/Virgo gravitational wave detectors. The rapidity, ... More
Serendipitous Discovery of PSR J1431-6328 as a Highly-Polarized Point Source with the Australian SKA PathfinderAug 08 2019We identified a highly-polarized, steep-spectrum radio source in a deep image with the Australian Square Kilometre Array Pathfinder (ASKAP) telescope at 888 MHz. After considering and rejecting a stellar origin for this source, we discovered a new millisecond ... More
Variability-based AGN selection using image subtraction in the SDSS and LSST eraDec 17 2013With upcoming all sky surveys such as LSST poised to generate a deep digital movie of the optical sky, variability-based AGN selection will enable the construction of highly-complete catalogs with minimum contamination. In this study, we generate $g$-band ... More
Status of the UC-Berkeley SETI EffortsAug 16 2011Sep 07 2011We summarize radio and optical SETI programs based at the University of California, Berkeley. The SEVENDIP optical pulse search looks for ns time scale pulses at visible wavelengths using an automated 30 inch telescope. The ongoing SERENDIP V.v sky survey ... More
Quantum Canonical Transformations and Integrability: Beyond Unitary TransformationsFeb 15 1993Sep 06 1993Quantum canonical transformations are defined in analogy to classical canonical transformations as changes of the phase space variables which preserve the Dirac bracket structure. In themselves, they are neither unitary nor non-unitary. A definition of ... More
Evolving Constants of MotionJul 18 1995A critical presentation of Rovelli's ``evolving constants of motion'' is given. Previous criticisms by Kucha\v{r} concerning the role of factor ordering and the non-existence of observables are dealt with and shown to be unfounded. Kucha\v{r}'s criticisms ... More
Homotopy sphere representations for matroidsMar 16 2009For any rank $r$ oriented matroid $M$, a construction is given of a "topological representation" of $M$ by an arrangement of homotopy spheres in a simplicial complex which is homotopy equivalent to $S^{r-1}$. The construction is completely explicit and ... More
Excited quark production at a 100 TeV VLHCSep 03 2013Sep 05 2013I look for a dijet resonance produced by an excited quark q* in a simulated sample corresponding to 3 ab^{-1} of pp collisions at $\sqrt{s} = 100$ TeV. Using a cut and count analysis approach I demonstrate the potential to explore q* masses up to 50 TeV, ... More
The Hidden Internet of Iran: Private Address Allocations on a National NetworkSep 28 2012While funding agencies have provided substantial support for the developers and vendors of services that facilitate the unfettered flow of information through the Internet, little consolidated knowledge exists on the basic communications network infrastructure ... More
An elegant solution of the n-body Toda problemJul 19 1995The solution of the classical open-chain n-body Toda problem is derived from an ansatz and is found to have a highly symmetric form. The proof requires an unusual identity involving Vandermonde determinants. The explicit transformation to action-angle ... More
The use of exp(iS[x]) in the sum over historiesAug 17 1993The use of $\sum \exp(iS[x])$ as the generic form for a sum over histories in configuration space is discussed critically and placed in its proper context. The standard derivation of the sum over paths by discretizing the paths is reviewed, and it is ... More
Unitary Equivalence of the Metric and Holonomy Formulations of 2+1 Dimensional Quantum Gravity on the TorusOct 13 1992Dec 31 1992Recent work on canonical transformations in quantum mechanics is applied to transform between the Moncrief metric formulation and the Witten-Carlip holonomy formulation of 2+1-dimensional quantum gravity on the torus. A non-polynomial factor ordering ... More
Quantum Backreaction on ``Classical'' VariablesJun 28 1994Nov 17 1994A mathematically consistent procedure for coupling quasiclassical and quantum variables through coupled Hamilton-Heisenberg equations of motion is derived from a variational principle. During evolution, the quasiclassical variables become entangled with ... More
Special functions from quantum canonical transformationsOct 26 1993Jun 01 1994Quantum canonical transformations are used to derive the integral representations and Kummer solutions of the confluent hypergeometric and hypergeometric equations. Integral representations of the solutions of the non-periodic three body Toda equation ... More
K-theoretic Chern class formulas for vexillary degeneracy lociDec 31 2016Jun 04 2019Using raising operators and geometric arguments, we establish formulas for the K-theory classes of degeneracy loci in classical types. We also find new determinantal and Pfaffian expressions for classical cases considered by Giambelli: the loci where ... More
Gravitational waveforms from the evaporating ACO cosmic string loopMar 28 2009The linearly polarized gravitational waveforms from a certain type of rotating, evaporating cosmic string - the Allen-Casper-Ottewill loop - are constructed and plotted over the lifetime of the loop. The formulas for the waveforms are simple and exact, ... More
A Local Resolution of the Problem of Time. VII. Constraint ClosureJun 09 2019Jul 09 2019We now set up Constraint Closure in a manner consistent with Temporal and Configurational Relationalism. This requires modifying the Dirac Algorithm - which addresses the Constraint Closure Problem facet of the Problem of Time piecemeal - to the TRi-Dirac ... More
A Local Resolution of the Problem of Time. III. The other classical facets piecemealMay 15 2019Jul 08 2019We introduce seven further local facets of the classical Problem of Time, and underlying Background Independence aspects, the previous two Articles having covered one further facet-and-aspect each for a total of nine. I.e. Constraint Closure, Assignment ... More
Shape DerivativesOct 23 2018Shape Theory, together with Shape-and-Scale Theory, comprise Relational Theory. This consists of $N$-point models on a manifold $M$, for which some geometrical automorphism group $G$ is regarded as meaningless and is thus quotiented out from the $N$-point ... More
Spaces of Observables from Solving PDEs. I. Translation-Invariant TheorySep 20 2018Oct 07 2018Finding classical canonical observables consists of taking a function space over phase space. For constrained theories, these functions must form zero brackets with a closed algebraic structure of first-class constraints. This brackets condition can moreover ... More
Maximal Angle Flow on the Shape Sphere of TrianglesDec 18 2017There has been recent work using Shape Theory to answer the longstanding and conceptually interesting problem of what is the probability that a triangle is obtuse. This is resolved by three kissing cap-circles of rightness being realized on the shape ... More
Configuration Spaces in Fundamental PhysicsMar 05 2015Apr 19 2016I consider configuration spaces for $N$-body problems, gauge theories and for GR in both geometrodynamical and Ashtekar variables forms, including minisuperspace and inhomogeneous perturbations thereabout in the former case. These examples include many ... More
Quantum Cosmology will need to become a Numerical SubjectJun 24 2013Jun 26 2013The inhomogeneous fluctuations that underlie structure formation - galaxies and CMB hotspots - might have been seeded by quantum cosmological fluctuations, as magnified by some inflationary mechanism. The Halliwell-Hawking model for these, as a lower-energy ... More
Relational Quadrilateralland. I. The Classical TheoryFeb 19 2012Nov 25 2013Relational particle mechanics models bolster the relational side of the absolute versus relational motion debate, and are additionally toy models for the dynamical formulation of General Relativity and its Problem of Time. They cover two aspects that ... More
Shape Space Methods for Quantum Cosmological TrianglelandSep 13 2009Oct 18 2010With toy modelling of conceptual aspects of quantum cosmology and the problem of time in quantum gravity in mind, I study the classical and quantum dynamics of the pure-shape (i.e. scale-free) triangle formed by 3 particles in 2-d. I do so by importing ... More
Problem of Time: Temporal Relationalism Compatibility of Other Local Classical Facets CompletedJun 11 2015Temporal Relationalism (TR) is that there is no time for the universe as a whole at the primary level. Time emerges rather at a secondary level; one compelling idea for this is Mach's `time is to be abstracted from change'. TR leads to, and better explains, ... More
Minisuperspace model of Machian Resolution of Problem of Time. I. Isotropic CaseJul 07 2013Feb 22 2014A local resolution to the Problem of Time that is Machian and was previously demonstrated for various relational mechanics models is here shown to work for a more widely studied quantum cosmological model. Namely, closed isotropic minisuperspace GR with ... More
Problem of Time in Quantum GravityJun 11 2012Aug 16 2012The Problem of Time occurs because the `time' of GR and of ordinary Quantum Theory are mutually incompatible notions. This is problematic in trying to replace these two branches of physics with a single framework in situations in which the conditions ... More
Does relationalism alone control geometrodynamics with sources?Nov 02 2007This paper concerns relational first principles from which the Dirac procedure exhaustively picks out the geometrodynamics corresponding to general relativity as one of a handful of consistent theories. This was accompanied by a number of results and ... More
Records TheorySep 12 2007Sep 23 2009In quantum gravity, one seeks to combine quantum mechanics and general relativity. In such attempts, one comes across the `problem of time' impasse: the notion of time is conceptually different in each of these theories. In this paper, I consider the ... More
Emergent Semiclassical Time in Quantum Gravity. I. Mechanical ModelsNov 01 2006Nov 04 2007Strategies intended to resolve the problem of time in quantum gravity by means of emergent or hidden timefunctions are considered in the arena of relational particle toy models. In situations with `heavy' and `light' degrees of freedom, two notions of ... More
On the recovery of geometrodynamics from two different sets of first principlesNov 14 2005Aug 12 2006The conventional spacetime formulation of general relativity may be recast as a dynamics of spatial 3-geometries (geometrodynamics). Furthermore, geometrodynamics can be derived from first principles. I investigate two distinct sets of these: (i) Hojman, ... More
Relational Quadrilateralland. Analogues of Isospin and HyperchargeFeb 19 2012Aug 07 2013I consider the momenta and conserved quantities for CP^2 interpreted as the space of quadrilaterals. This builds on seminar I and II's kinematics via making use of MacFarlane's work considering the SU(3)-like (and thus particle physics-like) conserved ... More
Foundations of Relational Particle DynamicsJun 26 2007Nov 08 2009Relational particle dynamics include the dynamics of pure shape and cases in which absolute scale or absolute rotation are additionally meaningful. These are interesting as regards the absolute versus relative motion debate as well as discussion of conceptual ... More
Geometry, EFE's and Foundations for Brane CosmologyFeb 02 2004I argue that GR Cauchy and Initial Value Problem mathematics is a valuable source of ideas for braneworlds based on higher-dimensional Einstein field equations.
A note on quantum products of Schubert classes in a GrassmannianAug 22 2006Given two Schubert classes $\sigma_{\lambda}$ and $\sigma_{\mu}$ in the quantum cohomology of a Grassmannian, we construct a partition $\nu$, depending on $\lambda$ and $\mu$, such that $\sigma_{\nu}$ appears with coefficient 1 in the lowest (or highest) ... More
Alternative versions of the Johnson homomorphisms and the LMO functorFeb 26 2019Sep 11 2019Let $\Sigma$ be a compact connected oriented surface with one boundary component and let $\mathcal{M}$ denote the mapping class group of $\Sigma$. By considering the action of $\mathcal{M}$ on the fundamental group of $\Sigma$ it is possible to define ... More
A survey of food recommendersSep 08 2018Sep 15 2018Everyone eats. However, people do not always know what to eat. They need a little help and inspiration. Consequently, a number of apps, services, and programs have developed recommenders around food. These cover food, meal, recipe, and restaurant recommendations, ... More
Nijenhuis-type variants of Local Theory of Background IndependenceAug 01 2019A local resolution of the Problem of Time has recently been given, alongside reformulation as a local theory of Background Independence. The classical part of this can be viewed as requiring just Lie's Mathematics, albeit entrenched in subsequent Topology ... More
Specific PDEs for Preserved Quantities in Geometry. III. 1-d Projective Transformations and SubgroupsSep 06 2018Sep 24 2018We extend finding geometrically-significant preserved quantities by solving specific PDEs to 1-$d$ projective transformations and subgroups. This can be viewed not only as a purely geometrical problem but also as a subcase of finding physical observables, ... More
A Local Resolution of the Problem of TimeSep 06 2018Sep 24 2018We here announce and outline a solution of this major and longstanding foundational problem, dealing with all seven of its heavily-interrelated local facets.
Absolute versus Relational Debate: a Modern Global VersionMay 24 2018Suppose one seeks to free oneself from a symmetric absolute space by quotienting out its symmetry group. This in general however fails to erase all memory of this absolute space's symmetry properties. Stratification is one major reason for this, which ... More
Shape (In)dependent Inequalities for Triangleland's Jacobi and Democratic-Linear Ellipticity QuantititiesDec 12 2017Sides and medians are both Jacobi coordinate magnitudes, moreover then equably entering the spherical coordinates on Kendall's shape sphere and the Hopf coordinates. This motivates treating medians on the same footing as sides in triangle geometry and ... More
Alice in Triangleland: Lewis Carroll's Pillow Problem and Variants Solved on Shape Space of TrianglesNov 30 2017We provide a natural answer to Lewis Carroll's pillow problem of what is the probability that a triangle is obtuse, Prob(Obtuse). This arises by straightforward combination of a) Kendall's Theorem - that the space of all triangles is a sphere - and b) ... More
Problem of Time: Facets and Machian StrategyJun 25 2013Jul 15 2014The Problem of Time is that `time' in each of ordinary quantum theory and general relativity are mutually incompatible notions. This causes difficulties in trying to put these two theories together to form a theory of Quantum Gravity. The Problem of Time ... More
New interpretation of variational principles for gauge theories. I. Cyclic coordinate alternative to ADM splitNov 02 2007I show how there is an ambiguity in how one treats auxiliary variables in gauge theories including general relativity cast as 3 + 1 geometrodynamics. Auxiliary variables may be treated pre-variationally as multiplier coordinates or as the velocities corresponding ... More
Relational mechanics of shape and scaleJan 07 2010Feb 15 2010Relational particle mechanics models (RPM's) are useful models for the problem of time in quantum gravity and other foundational issues in quantum cosmology. Some concrete examples of scalefree RPM's have already been studied, but it is the case with ... More
Variations on the Seventh Route to RelativityFeb 10 2003Nov 03 2003As motivated in the full abstract, this paper further investigates Barbour, Foster and O Murchadha (BFO)'s 3-space formulation of GR. This is based on best-matched lapse-eliminated actions and gives rise to several theories including GR and a conformal ... More
A Local Resolution of the Problem of Time. IV. Quantum outline and piecemeal ConclusionMay 15 2019Jun 09 2019In this final preliminary piecemeal treatment of local Problem of Time facets, and underlying Background Independence aspects, we first reconsider the nine local facets and aspects considered so far at the quantum level. This is essential both to appreciate ... More
Geometry from Brackets ConsistencyNov 01 2018We argue for Brackets Consistency to be a `Pillar of Geometry', i.e.\ a foundational approach, other Pillars being 1) Euclid's constructive approach, 2) the algebraic approach, 3) the projective approach, and 4) the geometrical automorphism groups `Erlangen' ... More
Specific PDEs for Preserved Quantities in Geometry. I. Similarities and SubgroupsSep 06 2018Sep 24 2018We provide specific PDEs for preserved quantities $Q$ in Geometry, as well as a bridge between this and specific PDEs for observables $O$ in Physics. We furthermore prove versions of four other theorems either side of this bridge: the below enumerated ... More
Machian Classical and Semiclassical Emergent TimeMay 21 2013Nov 25 2013Classical and semiclassical schemes are presented that are timeless at the primary level and recover time from Mach's `time is to be abstracted from change' principle at the emergent secondary level. The semiclassical scheme is a Machian variant of the ... More
On the Semiclassical Approach to Quantum CosmologyJan 25 2011The emergent semiclassical time approach to resolving the problem of time in quantum gravity involves heavy slow degrees of freedom providing via an approximately Hamilton-Jacobi equation an approximate timestandard with respect to which the quantum mechanics ... More
Smallest Relational Mechanics Model of Quantum CosmologyAug 13 2009Relational particle mechanics are models in which there is, overall, no time, position, orientation (nor, sometimes, scale). They are useful for whole-universe modelling - the setting for quantum cosmology. This note concerns 3 particles in 1d in shape-scale ... More
A Local Resolution of the Problem of Time. XIV. Grounding on Lie's MathematicsJul 31 2019In a major advance and simplification of this field, we show that A Local Resolution of the Problem of Time - also viewable as A Local Theory of Background Independence - can at the classical level be described solely by of Lie's Mathematics. This comprises ... More
Properties of Norms on SetsNov 06 2018We investigate the norms appearing in the forcing from combinatorial point of view. We make first steps towards building a catalog of the norms appearing in multiple settings and sources, reviewing four norms from Bartoszy\'nski and Judah [1], Ros{\l}anowski ... More
Parallel Multi Channel Convolution using General Matrix MultiplicationApr 06 2017Jul 03 2017Convolutional neural networks (CNNs) have emerged as one of the most successful machine learning technologies for image and video processing. The most computationally intensive parts of CNNs are the convolutional layers, which convolve multi-channel images ... More
Statistical properties of paired fixed fieldsJun 05 2018The initial conditions of cosmological simulations are commonly drawn from a Gaussian ensemble. The limited number of modes inside a simulation volume gives rise to statistical fluctuations known as \textit{sample variance}, limiting the accuracy of simulation ... More
Error Analysis and Improving the Accuracy of Winograd Convolution for Deep Neural NetworksMar 29 2018Sep 22 2018Modern deep neural networks (DNNs) spend a large amount of their execution time computing convolutions. Winograd's minimal algorithm for small convolutions can greatly reduce the number of arithmetic operations. However, a large reduction in floating ... More
The NASA-UC Eta-Earth Program: III. A Super-Earth orbiting HD 97658 and a Neptune-mass planet orbiting Gl 785Nov 01 2010We report the discovery of planets orbiting two bright, nearby early K dwarf stars, HD 97658 and Gl 785. These planets were detected by Keplerian modelling of radial velocities measured with Keck-HIRES for the NASA-UC Eta-Earth Survey. HD 97658 b is a ... More
Colors of c-type RR Lyrae Stars and Interstellar ReddeningOct 02 2013RR Lyrae stars pulsating in the fundamental mode have long been used to measure interstellar reddening, based on their observed uniformity of $B-V$ color at minimum light after small corrections for metallicity and period are applied. However, little ... More
On the Co-existence of TD-LTE and Radar over 3.5 GHz Band: An Experimental StudyMay 03 2016This paper presents a pioneering study based on a series of experiments on the operation of commercial Time-Division Long-Term Evolution (TD-LTE) systems in the presence of pulsed interfering signals in the 3550-3650 MHz band. TD-LTE operations were carried ... More
Quantum computing by color-code lattice surgeryJul 18 2014We demonstrate how to use lattice surgery to enact a universal set of fault-tolerant quantum operations with color codes. Along the way, we also improve existing surface-code lattice-surgery methods. Lattice-surgery methods use fewer qubits and the same ... More
A First Look at White Dwarf - M Dwarf Pairs in the Sloan Digital Sky Survey (SDSS)Feb 19 2003We have identified 109 White Dwarf (WD) - M dwarf pairs in the Sloan Digital Sky Survey (SDSS) with g < 20th magnitude. For each system we determined the temperature of the WD primary and the spectral type of the M dwarf secondary. Using H-alpha emission ... More
The Allen Telescope Array Search for Electrostatic Discharges on MarsNov 02 2011The Allen Telescope Array was used to monitor Mars between 9 March and 2 June 2010, over a total of approximately 30 hours, for radio emission indicative of electrostatic discharge. The search was motivated by the report from Ruf et al. (2009) of the ... More
The SDSS-2MASS-WISE Ten Dimensional Stellar Color LocusMar 07 2014We present the fiducial main sequence stellar locus traced by 10 photometric colors observed by SDSS, 2MASS, and WISE. Median colors are determined using 1,052,793 stars with r-band extinction less than 0.125. We use this locus to measure the dust extinction ... More
Fault-tolerant quantum computing with color codesAug 29 2011We present and analyze protocols for fault-tolerant quantum computing using color codes. We present circuit-level schemes for extracting the error syndrome of these codes fault-tolerantly. We further present an integer-program-based decoding algorithm ... More
The LOFAR Magnetism Key Science ProjectMar 12 2012Mar 30 2012Measuring radio waves at low frequencies offers a new window to study cosmic magnetism, and LOFAR is the ideal radio telescope to open this window widely. The LOFAR Magnetism Key Science Project (MKSP) draws together expertise from multiple fields of ... More
A Description of Quasar Variability Measured Using Repeated SDSS and POSS ImagingDec 03 2011May 04 2012We provide a quantitative description and statistical interpretation of the optical continuum variability of quasars. The Sloan Digital Sky Survey (SDSS) has obtained repeated imaging in five UV-to-IR photometric bands for 33,881 spectroscopically confirmed ... More
Cataclysmic Variables from SDSS VII. The Seventh Year (2006)Jan 21 2009Coordinates, magnitudes and spectra are presented for 39 cataclysmic variables found in Sloan Digital Sky Survey spectra that were primarily obtained in 2006. Of these, 12 were CVs identified prior to the SDSS spectra (GY Cnc, GO Com, ST LMi, NY Ser, ... More
The Impact of the Astro2010 Recommendations on Variable Star ScienceFeb 23 2009The next decade of survey astronomy has the potential to transform our knowledge of variable stars. Stellar variability underpins our knowledge of the cosmological distance ladder, and provides direct tests of stellar formation and evolution theory. Variable ... More
The NASA-UC Eta-Earth Program: I. A Super-Earth Orbiting HD 7924Jan 28 2009We report the discovery of the first low-mass planet to emerge from the NASA-UC Eta-Earth Program, a super-Earth orbiting the K0 dwarf HD 7924. Keplerian modeling of precise Doppler radial velocities reveals a planet with minimum mass M_P sin i = 9.26 ... More
Low-memory GEMM-based convolution algorithms for deep neural networksSep 08 2017Deep neural networks (DNNs) require very large amounts of computation both for training and for inference when deployed in the field. A common approach to implementing DNNs is to recast the most computationally expensive operations as general matrix multiplication ... More
D4M 2.0 Schema: A General Purpose High Performance Schema for the Accumulo DatabaseJul 15 2014Non-traditional, relaxed consistency, triple store databases are the backbone of many web companies (e.g., Google Big Table, Amazon Dynamo, and Facebook Cassandra). The Apache Accumulo database is a high performance open source relaxed consistency database ... More
Probing spin-phonon interactions in silicon carbide with Gaussian acousticsApr 29 2018Aug 04 2018Hybrid spin-mechanical systems provide a platform for integrating quantum registers and transducers. Efficient creation and control of such systems require a comprehensive understanding of the individual spin and mechanical components as well as their ... More
Characterizing the Optical Variability of Bright Blazars: Variability-Based Selection of Fermi AGNSep 17 2012We investigate the use of optical photometric variability to select and identify blazars in large-scale time-domain surveys, in part to aid in the identification of blazar counterparts to the ~30% of gamma-ray sources in the Fermi 2FGL catalog still lacking ... More
WASP-8b: a retrograde transiting planet in a multiple systemJun 26 2010We report the discovery of WASP-8, a transiting planet of 2.25+-0.08 M_Jup on a strongly inclined eccentric 8.15-day orbit, moving in a retrograde direction to the rotation of its late-G host star. Evidence is found that the star is in a multiple stellar ... More
Efficient Threshold Aggregation of Moving ObjectsNov 07 2006May 01 2007Calculating aggregation operators of moving point objects, using time as a continuous variable, presents unique problems when querying for congestion in a moving and changing (or dynamic) query space. We present a set of congestion query operators, based ... More
The trouble with twisting (2,0) theoryNov 13 2013Jan 28 2014We consider a twisted version of the abelian $(2,0)$ theory placed upon a Lorenzian six-manifold with a product structure, $M_6=C \times M_4 $. This is done by an investigation of the free tensor multiplet on the level of equations of motion, where the ... More
Foundations for a theory of complex matroidsMay 19 2010Jun 28 2012We explore a combinatorial theory of linear dependency in complex space, "complex matroids", with foundations analogous to those for oriented matroids. We give multiple equivalent axiomatizations of complex matroids, showing that this theory captures ... More
Abeliants and their application to an elementary construction of JacobiansDec 05 2001The {\em abeliant} is a polynomial rule for producing an $n$ by $n$ matrix with entries in a given ring from an $n$ by $n$ by $n+2$ array of elements of that ring. The theory of abeliants, first introduced in an earlier paper of the author, is redeveloped ... More
Convergence of the largest singular value of a polynomial in independent Wigner matricesMar 24 2011Jul 08 2013For polynomials in independent Wigner matrices, we prove convergence of the largest singular value to the operator norm of the corresponding polynomial in free semicircular variables, under fourth moment hypotheses. We actually prove a more general result ... More
A double complex for computing the sign-cohomology of the universal ordinary distributionOct 21 1997We give a new method for solving a problem originally solved about 20 years ago by Sinnott and Kubert, namely that of computing the cohomology of the universal ordinary distribution with respect to the action of the two-element group generated by complex ... More
MWStat: A Modulated Web-Based Statistical SystemApr 29 2016In this paper we present the development of a modulated web based statistical system, hereafter MWStat, which shifts the statistical paradigm of analyzing data into a real time structure. The MWStat system is useful for both online storage data and questionnaires ... More
Sp(3,R) Monge geometries in dimension 8Jun 28 2016We study a geometry associated with rank 3 distributions in dimension 8, whose symbol algebra is constant and has a simple Lie algebra sp(3,R) as Tanaka prolongation. We restrict our considerations to only those distributions that are defined in terms ... More
Scalar curvature, metric degenerations and the static vacuum Einstein equations on 3-manifolds, IDec 20 1999We study Yamabe metrics, and the moduli space of Yamabe metrics, on an arbitrary closed 3-manifold M. The main focus is on the boundary behavior of the moduli space, i.e. the behavior of degenerating sequences of unit volume Yamabe metrics on M. It is ... More