Results for "Rebecca L. Russell"

total 107044took 0.14s
A 3D Probabilistic Deep Learning System for Detection and Diagnosis of Lung Cancer Using Low-Dose CT ScansFeb 08 2019Jun 18 2019We introduce a new computer aided detection and diagnosis system for lung cancer screening with low-dose CT scans that produces meaningful probability assessments. Our system is based entirely on 3D convolutional neural networks and achieves state-of-the-art ... More
Learning to Repair Software Vulnerabilities with Generative Adversarial NetworksMay 18 2018Oct 28 2018Motivated by the problem of automated repair of software vulnerabilities, we propose an adversarial learning approach that maps from one discrete source domain to another target domain without requiring paired labeled examples or source and target domains ... More
High-Precision Entropy Values for Spanning Trees in LatticesApr 29 2003Nov 06 2003Shrock and Wu have given numerical values for the exponential growth rate of the number of spanning trees in Euclidean lattices. We give a new technique for numerical evaluation that gives much more precise values, together with rigorous bounds on the ... More
Lattice Paths, Young Tableaux, and Weight MultiplicitiesAug 27 2015For $\ell \geq 1$ and $k \geq 2$, we consider certain admissible sequences of $k-1$ lattice paths in a colored $\ell \times \ell$ square. We show that the number of such admissible sequences of lattice paths is given by the sum of squares of the number ... More
Speckle-based hyperspectral imaging combining multiple scattering and compressive sensing in nanowire matsMay 08 2017Encoding of spectral information onto monochrome imaging cameras is of interest for wavelength multiplexing and hyperspectral imaging applications. Here, the complex spatio-spectral response of a disordered material is used to demonstrate retrieval of ... More
Real-Time Object Pose Estimation with Pose Interpreter NetworksAug 03 2018In this work, we introduce pose interpreter networks for 6-DoF object pose estimation. In contrast to other CNN-based approaches to pose estimation that require expensively annotated object pose data, our pose interpreter network is trained entirely on ... More
Discovery of a z = 7.452 High Equivalent Width Lyman-α Emitter from the Hubble Space Telescope Faint Infrared Grism SurveyDec 15 2017We present the results of an unbiased search for Ly{\alpha} emission from continuum-selected 6 < z < 8 galaxies. Our dataset consists of 160 orbits of G102 slitless grism spectroscopy obtained with the Hubble Space Telescope (HST) Wide Field Camera 3 ... More
Deep Learning Enabled Real Time Speckle Recognition and Hyperspectral Imaging using a Multimode Fiber ArrayApr 07 2019Jun 01 2019We demonstrate the use of deep learning for fast spectral deconstruction of speckle patterns. The artificial neural network can be effectively trained using numerically constructed multispectral datasets taken from a measured spectral transmission matrix. ... More
A Two-Dimensional Spectroscopic Study of Emission Line Galaxies in the Faint Infrared Grism Survey (FIGS) I: Detection Method and CatalogJun 05 2018Nov 09 2018We present the results from the application of a two-dimensional emission line detection method, EMission-line two-Dimensional (EM2D), to the near-infrared G102 grism observations obtained with the Wide-Field Camera 3 (WFC3) as part of the Cycle 22 {\em ... More
The Mass Distribution of the Unusual Merging Cluster Abell 2146 from Strong LensingSep 21 2016Abell 2146 consists of two galaxy clusters that have recently collided close to the plane of the sky, and it is unique in showing two large shocks on $\textit{Chandra X-ray Observatory}$ images. With an early stage merger, shortly after first core passage, ... More
Transport map accelerated adaptive importance sampling, and application to inverse problems arising from multiscale stochastic reaction networksJan 31 2019In many applications, Bayesian inverse problems can give rise to probability distributions which contain complexities due to the Hessian varying greatly across parameter space. This complexity often manifests itself as lower dimensional manifolds on which ... More
Efficient characterisation of large deviations using population dynamicsNov 14 2017May 09 2018We consider population dynamics as implemented by the cloning algorithm for analysis of large deviations of time-averaged quantities. Using the simple symmetric exclusion process as a prototypical example, we investigate the convergence of the results ... More
GCM simulations of Titan's middle and lower atmosphere and comparison to observationsDec 26 2014Simulation results are presented from a new general circulation model (GCM) of Titan, the Titan Atmospheric Model (TAM), which couples the Flexible Modeling System (FMS) spectral dynamical core to a suite of external/sub-grid-scale physics. These include ... More
Silicate Emission in the TW Hydrae AssociationAug 01 2000The TW Hydrae Association is the nearest young stellar association. Among its members are HD 98800, HR 4796A, and TW Hydrae itself, the nearest known classical T Tauri star. We have observed these three stars spectroscopically between 3 and 13 microns. ... More
The mixed problem in Lipschitz domains with general decompositions of the boundaryNov 07 2011This paper continues the study of the mixed problem for the Laplacian. We consider a bounded Lipschitz domain $\Omega\subset \reals^n$, $n\geq2$, with boundary that is decomposed as $\partial\Omega=D\cup N$, $D$ and $N$ disjoint. We let $\Lambda$ denote ... More
Guidefill: GPU Accelerated, Artist Guided Geometric Inpainting for 3D ConversionNov 16 2016Jul 31 2017The conversion of traditional film into stereo 3D has become an important problem in the past decade. One of the main bottlenecks is a disocclusion step, which in commercial 3D conversion is usually done by teams of artists armed with a toolbox of inpainting ... More
A 3D Probabilistic Deep Learning System for Detection and Diagnosis of Lung Cancer Using Low-Dose CT ScansFeb 08 2019We introduce a new end-to-end computer aided detection and diagnosis system for lung cancer screening using low-dose CT scans. Our system is based on 3D convolutional neural networks and achieves state-of-the-art performance for both lung nodule detection ... More
Comparing algorithms for sorting with t stacks in seriesApr 08 2004Jun 18 2004We show that the left-greedy algorithm is a better algorithm than the right-greedy algorithm for sorting permutations using t stacks in series when t>1. We also supply a method for constructing some permutations that can be sorted by t stacks in series ... More
Promotion on Generalized Oscillating Tableaux and Web RotationSep 12 2017We introduce the notion of a generalized oscillating tableau and define a promotion operation on such tableaux that generalizes the classical promotion operation on standard Young tableaux. As our main application, we show that this promotion corresponds ... More
The Adjoints of the Schur FunctorJan 14 2016Jan 20 2016We show that the left and right adjoint of the Schur functor can be expressed in terms of the monoidal structure of strict polynomial functors. Using this result we give a necessary and sufficient condition for when the tensor product of two simple strict ... More
$p$-adic Hodge theory in rigid analytic familiesJun 24 2013Mar 08 2016We study the functors $\D_{\B_\ast}(V)$, where $\B_\ast$ is one of Fontaine's period rings and $V$ is a family of Galois representations with coefficients in an affinoid algebra $A$. We show that $\D_{\HT}(V)=\oplus_{i\in\Z}(\D_{\Sen}(V)\cdot t^i)^{\Gamma_K}$, ... More
The naked emergence of solar active regions observed with SDO/HMISep 19 2012We take advantage of the HMI/SDO instrument to study the naked emergence of active regions from the first imprints of the magnetic field on the solar surface. To this end, we followed the first 24 hours in the life of two rather isolated ARs that appeared ... More
Partizan Kayles and Misere InvertibilitySep 06 2013The impartial combinatorial game Kayles is played on a row of pins, with players taking turns removing either a single pin or two adjacent pins. A natural partizan variation is to allow one player to remove only a single pin and the other only a pair ... More
An Empirical Evaluation of Probabilistic Lexicalized Tree Insertion GrammarsAug 04 1998We present an empirical study of the applicability of Probabilistic Lexicalized Tree Insertion Grammars (PLTIG), a lexicalized counterpart to Probabilistic Context-Free Grammars (PCFG), to problems in stochastic natural-language processing. Comparing ... More
What is Schur positivity and how common is it?Sep 12 2018This is a short note about Schur positivity. We introduce Schur polynomials and explain how they appear in the representation theory of the general linear group. We end with a new result of the author with F. Bergeron and V. Reiner that gives the probability ... More
The genus of projective curves on complete intersection surfacesAug 15 2014Sep 03 2014We bound the genus of a projective curve lying on a complete intersection surface in terms of its degree and the degrees of the defining equations of the surface on which it lies.
Integrability of generalised type II defects in affine Toda field theorySep 12 2017Sep 13 2017The Liouville integrability of the generalised type II defects is investigated. Full integrability is not considered, only the existence of an infinite number of conserved quantities associated with a system containing a defect. For defects in affine ... More
A Decreasing Stack and an Increasing Stack in SeriesJan 28 2013We study a sorting machine consisting of two stacks in series where the first stack has the added restriction such that entries in the stack must be in decreasing order from top to bottom. We give the basis of the class of permutations that are sortable ... More
Computing Higher Indicators for the Double of a Symmetric GroupJun 28 2012In this paper we explicitly determine all indicators for the Drinfel'd doubles of the symmetric group acting upon up to 10 objects. We explore when distinct characters give exactly the same indicators and when the indicators have a zero value. We find ... More
The Algebra of an Age for Metrically Homogeneous Graphs of Generic TypeJul 05 2019Metrically homogeneous graphs are connected graphs which, when endowed with the path metric, are homogeneous as metric spaces. Here we consider a class of countable metrically homogeneous graphs. The algebra of an age is a concept introduced by Cameron ... More
A New Method for Characterizing Very-Low-Mass Companions with Low Resolution Near-Infrared SpectroscopyApr 20 2015Apr 22 2015We present a new and computationally efficient method for characterizing very low mass companions using low resolution ($R\sim$30) near-infrared ($YJH$) spectra from high contrast imaging campaigns with integral field spectrograph (IFS) units. We conduct ... More
Thermal evolution of quasi-1D spin correlations within the anisotropic triangular lattice of $α$-NaMnO$_2$Oct 19 2018Magnetic order on the spatially anisotropic triangular lattice of $\alpha$-NaMnO$_2$ is studied via neutron diffraction measurements. The transition into a commensurate, collinear antiferromagnetic ground state with $\mathbf{k}=(0.5, 0.5, 0)$ was found ... More
On the Maximum Number of k-Hooks of Partitions of nDec 14 2012Let $\alpha_k(\lambda)$ denote the number of $k$-hooks in a partition $\lambda$ and let $b(n,k)$ be the maximum value of $\alpha_k(\lambda)$ among partitions of $n$. Amdeberhan posed a conjecture on the generating function of $b(n,1)$. We give a proof ... More
White Dwarf Pollution by Asteroids from Secular ResonancesJul 07 2018In the past few decades, observations have revealed signatures of metals polluting the atmospheres of white dwarfs. The diffusion timescale for metals to sink from the atmosphere of a white dwarf is of the order of days for a hydrogen-dominated atmosphere. ... More
Dynamical two electron states in a Hubbard-Davydov modelApr 30 2004We study a model in which a Hubbard Hamiltonian is coupled to the dispersive phonons in a classical nonlinear lattice. Our calculations are restricted to the case where we have only two quasi-particles of opposite spins, and we investigate the dynamics ... More
TETRA Observation of Gamma Rays at Ground Level Associated with Nearby ThunderstormsDec 19 2013Terrestrial Gamma ray Flashes (TGFs) -- very short, intense bursts of electrons, positrons, and energetic photons originating from terrestrial thunderstorms -- have been detected with satellite instruments. TETRA, an array of NaI(Tl) scintillators at ... More
Distance covariance in metric spacesJun 28 2011Oct 03 2013We extend the theory of distance (Brownian) covariance from Euclidean spaces, where it was introduced by Sz\'{e}kely, Rizzo and Bakirov, to general metric spaces. We show that for testing independence, it is necessary and sufficient that the metric space ... More
Solar and Extrasolar Planet TaxonomyAug 02 2013Oct 11 2014A mass-based definition for planets is proposed with dynamical circumstances and compositional characteristics used to define types of planets. Dynamical planet classes include Principal planets, Belt planets, Moons, and Rogue planets. Compositional classes ... More
Abelianized fundamental group of the affine space over a finite field and big Witt vectors in several variablesSep 06 2015Let $X$ be a normal proper variety over a perfect field $k$. We describe abelian coverings of X in terms of the functor $\underline{\rm HDiv}_X$ of principal relative Cartier divisors on $X$. If the base field $k$ is finite, the geometric Galois group ... More
Strong Negative Type in SpheresMay 08 2019May 09 2019It is known that spheres have negative type, but only subsets with at most one pair of antipodal points have strict negative type. These are conditions on the (angular) distances within any finite subset of points. We show that subsets with at most one ... More
From Hierarchical to Relative HyperbolicityMay 29 2019Jul 15 2019We provide a simple, combinatorial criteria for a hierarchically hyperbolic space to be relatively hyperbolic by proving a new formulation of relative hyperbolicity in terms of hierarchy structures. In the case of clean hierarchically hyperbolic groups, ... More
Description of generalized Albanese varieties by curvesJun 15 2011Let X be a projective variety over an algebraically closed base field, possibly singular. The aim of this paper is to show that the generalized Albanese variety of Esnault-Srinivas-Viehweg can be computed from one general curve C in X, if the base field ... More
The Spread of Evidence-Poor Medicine via Flawed Social-Network AnalysisJul 16 2010May 05 2011The chronic widespread misuse of statistics is usually inadvertent, not intentional. We find cautionary examples in a series of recent papers by Christakis and Fowler that advance statistical arguments for the transmission via social networks of various ... More
Flat strips, Bowen-Margulis measures, and mixing of the geodesic flow for rank one CAT(0) spacesOct 15 2014Oct 06 2017Let $X$ be a proper, geodesically complete CAT(0) space under a proper, non-elementary, isometric action by a group $\Gamma$ with a rank one element. We construct a generalized Bowen-Margulis measure on the space of unit-speed parametrized geodesics of ... More
Hardness as randomness: a survey of universal derandomizationApr 28 2003We survey recent developments in the study of probabilistic complexity classes. While the evidence seems to support the conjecture that probabilism can be deterministically simulated with relatively low overhead, i.e., that $P=BPP$, it also indicates ... More
Hyperbolic Space Has Strong Negative TypeAug 12 2014Feb 27 2015It is known that hyperbolic spaces have strict negative type, a condition on the distances of any finite subset of points. We show that they have strong negative type, a condition on every probability distribution of points (with integrable distance to ... More
Factors of IID on TreesJan 16 2014Sep 04 2016Classical ergodic theory for integer-group actions uses entropy as a complete invariant for isomorphism of IID (independent, identically distributed) processes (a.k.a. product measures). This theory holds for amenable groups as well. Despite recent spectacular ... More
Phase Transitions on Nonamenable GraphsAug 31 1999Jun 16 2000We survey known results about phase transitions in various models of statistical physics when the underlying space is a nonamenable graph. Most attention is devoted to transitive graphs and trees.
Singularity of Some Random Continued FractionsSep 16 1999We prove singularity of some distributions of random continued fractions that correspond to iterated function systems with overlap and a parabolic point. These arose while studying the conductance of Galton-Watson trees.
Applications of the Defect of a Finitely Presented FunctorOct 31 2012Jun 01 2016For an abelian category $\mathcal{A}$, the defect sequence $$0\longrightarrow F_0\longrightarrow F\overset{\varphi}{\longrightarrow} \big(w(F),\hspace{0.05cm}\underline{\ \ }\hspace{0.1cm} \big)\longrightarrow F_1\longrightarrow 0$$ of a finitely presented ... More
Efficient Search for Diverse Coherent ExplanationsJan 02 2019This paper proposes new search algorithms for counterfactual explanations based upon mixed integer programming. We are concerned with complex data in which variables may take any value from a contiguous range or an additional set of discrete states. We ... More
Baire category theory and Hilbert's Tenth Problem inside $\mathbb{Q}$Feb 10 2016For a ring R, Hilbert's Tenth Problem HTP(R) is the set of polynomial equations over R, in several variables, with solutions in R. We consider computability of this set for subrings R of the rationals. Applying Baire category theory to these subrings, ... More
Exit Boundaries of Multidimensional SDEsFeb 12 2019We show that solutions to multidimensional SDEs with Lipschitz coefficients and driven by Brownian motion never reach the set where all coefficients vanish unless the initial position belongs to that set.
Geometric class field theory with bounded ramification for surfacesNov 05 2012Jul 08 2015Let X be a smooth projective geometrically irreducible variety over a perfect field k and D an effective divisor on X. We consider a relative Chow group of modulus D, the Albanese variety of X of modulus D and the Abel-Jacobi map with modulus. For X a ... More
Determinantal Probability: Basic Properties and ConjecturesJun 10 2014We describe the fundamental constructions and properties of determinantal probability measures and point processes, giving streamlined proofs. We illustrate these with some important examples. We pose several general questions and conjectures.
Monotonicity of average return probabilities for random walks in random environmentsMay 21 2017We extend a result of Lyons (2016) from fractional tiling of finite graphs to a version for infinite random graphs. The most general result is as follows. Let $\bf P$ be a unimodular probability measure on rooted networks $(G, o)$ with positive weights ... More
Generalized Albanese and its dualJun 10 2006May 25 2009We consider categories of rational maps to algebraic groups and study existence and construction of universal objects for such categories, using the duality theory of Laumon 1-motives. In particular, we obtain functorial descriptions of the Albanese of ... More
A Note on Tail Triviality for Determinantal Point ProcessesJul 17 2018Oct 03 2018We give a very short proof that determinantal point processes have a trivial tail $\sigma$-field. This conjecture of the author has been proved by Osada and Osada as well as by Bufetov, Qiu, and Shamov. The former set of authors relied on the earlier ... More
Effectivizing Lusin's TheoremAug 17 2019Lusin's Theorem states that, for every Borel-measurable function $\bf{f}$ on $\mathbb R$ and every $\epsilon>0$, there exists a continuous function $\bf{g}$ on $\mathbb R$ which is equal to $\bf{f}$ except on a set of measure $<\epsilon$. We give a proof ... More
From Hierarchical to Relative HyperbolicityMay 29 2019We provide a simple, combinatorial criteria for a hierarchically hyperbolic space to be relatively hyperbolic by proving a new formulation of relative hyperbolicity in terms of hierarchy structures. In the case of clean hierarchically hyperbolic groups, ... More
Planar CAT(k) SubspacesJan 14 2010Let M_k be the complete, simply connected, Riemannian 2-manifold of constant curvature k \le 0. Let E be a closed, simply connected subspace of M_k with the property that every two points in E are connected by a rectifiable path in E. We show that E is ... More
Alignment CorrespondencesNov 24 2000We study correspondences of zero-dimensional subschemes of a smooth variety X "aligned" in the same way in inside the appropriate product of Hilbert schemes. We show that such correspondences have etale covering by other such correspondences that are ... More
Asymptotic Enumeration of Spanning TreesDec 11 2002Jul 15 2005We give new general formulas for the asymptotics of the number of spanning trees of a large graph. A special case answers a question of McKay (1983) for regular graphs. The general answer involves a quantity for infinite graphs that we call "tree entropy", ... More
Isomorphism and classification for countable structuresJul 09 2017Jul 19 2018We introduce a topology on the space of all isomorphism types represented in a given class of countable models, and use this topology as an aid in classifying the isomorphism types. This mixes ideas from effective descriptive set theory and computable ... More
Comparing Graphs of Different SizesFeb 22 2016Oct 18 2016We consider two notions describing how one finite graph may be larger than another. Using them, we prove several theorems for such pairs that compare the number of spanning trees, the return probabilities of random walks, and the number of independent ... More
Checkerboard Julia Sets for Rational MapsMar 19 2011Jun 20 2011In this paper, we consider the family of rational maps $$\F(z) = z^n + \frac{\la}{z^d},$$ where $n \geq 2$, $d\geq 1$, and$\la \in \bbC$. We consider the case where $\la$ lies in the main cardioid of one of the $n-1$ principal Mandelbrot sets in these ... More
Implosion of coronal loops during the impulsive phase of a solar flareSep 26 2013We study the relationship between implosive motions in a solar flare, and the energy redistribution in the form of oscillatory structures and particle acceleration. The flare SOL2012-03-09T03:53 (M6.4) shows clear evidence for an irreversible (stepwise) ... More
Discovery of Rapidly Moving Partial X-ray Absorbers within gamma CassiopeiaeAug 03 2016Gamma Cassiopeiae is an enigmatic Be star with unusually strong hard X-ray emission. The Suzaku observatory detected six rapid X-ray spectral hardening events called "softness dips" in a ~100 ksec duration observation in 2011. All the softness dip events ... More
3 - 14 Micron Spectroscopy of Comets C/2002 O4 (Honig), C/2002 V1 (NEAT), C/2002 X5 (Kudo-Fujikawa), C/2002 Y1 (Juels-Holvorcem), 69P/Taylor, and the Relationships among Grain Temperature, Silicate Band Strength and Structure among Comet FamiliesApr 19 2004We report 3 - 13 micron spectroscopy of 4 comets observed between August 2002 and February 2003: C/2002 O4 (Honig) on August 1, 2002, C/2002 V1 (NEAT) on Jan. 9 and 10, 2003, C/2002 X5 (Kudo-Fujikawa) on Jan. 9 and 10, 2003, and C/2002 Y1 (Juels-Holvorcem) ... More
Cometary Dust in the Debris Disks of HD 31648 and HD 163296: Two ``Baby'' beta PicsJul 22 1998The debris disks surrounding the pre-main sequence stars HD 31648 and HD 163296 were observed spectroscopically between 3 and 14 microns. Both possess a silicate emission feature at 10 microns which resembles that of the star beta Pictoris and those observed ... More
Cognitive Model Priors for Predicting Human DecisionsMay 22 2019Human decision-making underlies all economic behavior. For the past four decades, human decision-making under uncertainty has continued to be explained by theoretical models based on prospect theory, a framework that was awarded the Nobel Prize in Economic ... More
Tracking plumbing system dynamics at the Campi Flegrei caldera, Italy: High-resolution trace element mapping of the Astroni crystal cargoDec 28 2018The Campi Flegrei caldera (southern Italy) is one of the most hazardous volcanic systems on Earth, having produced >60 eruptions in the past 15 ka. The caldera remains active and its potential for future eruptions is high, posing a danger to the dense ... More
Cognitive Control in the Controllable ConnectomeJun 29 2016Cognition is supported by neurophysiological processes that occur both in local anatomical neighborhoods and in distributed large-scale circuits. Recent evidence from network control theory suggests that white matter pathways linking large-scale brain ... More
Quantum-enhanced tomography of unitary processesFeb 12 2014A fundamental task in photonics is to characterise an unknown optical process, defined by properties such as birefringence, spectral response, thickness and flatness. Amongst many ways to achieve this, single-photon probes can be used in a method called ... More
Amplitude mode in the planar triangular antiferromagnet Na$_{0.9}$MnO$_2$Oct 22 2018Amplitude modes arising from symmetry breaking in materials are of broad interest in condensed matter physics. These modes reflect an oscillation in the amplitude of a complex order parameter, yet are typically unstable and decay into oscillations of ... More
A new fast radio burst in the datasets containing the Lorimer burstFeb 15 2019We report the discovery of a new fast radio burst (FRB), FRB~010312, in archival data from a 1.4\,GHz survey of the Magellanic Clouds using the multibeam receiver on the Parkes 64\,m-diameter radio telescope. These data sets include the Lorimer burst ... More
Mid-Infrared Ethane Emission on Neptune and UranusFeb 24 2006We report 8- to 13-micron spectral observations of Neptune and Uranus from the NASA Infrared Telescope Facility spanning more than a decade. The spectroscopic data indicate a steady increase in Neptune's mean atmospheric 12-micron ethane emission from ... More
Lifting of Characters for Nonlinear Simply Laced GroupsSep 05 2008One aspect of the Langlands program for linear groups is lifting of characters, which relates virtual representations on a group $G$ with those on an endoscopic group for $G$. The goal of this paper is to extend this theory to nonlinear two-fold covers ... More
K-theoretic Poirier-Reutenauer bialgebraApr 16 2014We use the K-Knuth equivalence of Buch and Samuel to define a K-theoretic analogue of the Poirier-Reutenauer Hopf algebra. As an application, we rederive the K-theoretic Littlewood-Richardson rules of Thomas and Yong and of Buch and Samuel.
Lagrangian-type submanifolds of Spin(7) manifolds and their deformationsJan 27 2016In an earlier paper we showed that the space of deformations of a smooth, compact, orientable Harvey-Lawson submanifold HL in a G2 manifold M can be identified with the direct sum of the space of smooth functions and closed 2-forms on HL. In that paper, ... More
Trend Detection based Regret Minimization for Bandit ProblemsSep 15 2017We study a variation of the classical multi-armed bandits problem. In this problem, the learner has to make a sequence of decisions, picking from a fixed set of choices. In each round, she receives as feedback only the loss incurred from the chosen action. ... More
Chiral RKKY interaction in Pr2Ir2O7Jan 04 2013Motivated by the potential chiral spin liquid in the metallic spin ice Pr2Ir2O7, we consider how such a chiral state might be selected from the spin ice manifold. We propose that chiral fluctuations of the conducting Ir moments promote ferro-chiral couplings ... More
Load Balancing in Mobility-on-Demand Systems: Reallocation Via Parametric Control Using Concurrent EstimationApr 07 2019Jul 09 2019Mobility-on-Demand (MoD) systems require load balancing to maintain consistent service across regions with uneven demand subject to time-varying traffic conditions. The load-balancing objective is to jointly minimize the fraction of lost customer requests ... More
Missing Data in Sparse Transition Matrix Estimation for Sub-Gaussian Vector Autoregressive ProcessesFeb 26 2018High-dimensional time series data exist in numerous areas such as finance, genomics, healthcare, and neuroscience. An unavoidable aspect of all such datasets is missing data, and dealing with this issue has been an important focus in statistics, control, ... More
The concept of "character" in Dirichlet's theorem on primes in an arithmetic progressionSep 17 2012Jun 26 2013In 1837, Dirichlet proved that there are infinitely many primes in any arithmetic progression in which the terms do not all share a common factor. We survey implicit and explicit uses of Dirichlet characters in presentations of Dirichlet's proof in the ... More
Tandem Pairing in Heavy Fermion SuperconductorsDec 11 2009May 07 2010We examine the internal structure of the heavy fermion condensate, showing that it necessarily involves a d-wave pair of quasiparticles on neighboring lattice sites, condensed in tandem with a composite pair of electrons bound to a local moment, within ... More
Supermassive Black Hole Demographics: Evading $M - σ$May 31 2019We consider black hole - galaxy coevolution using simple analytic arguments. We focus on the fact that several supermassive black holes are known with masses significantly larger than suggested by the $M - {\sigma}$ relation, sometimes also with rather ... More
The Chow ring of the classifying space $BSO(2n,{\mathbb C})$Nov 19 2004We compute the Chow ring of the classifying space $BSO(2n,\C)$ in the sense of Totaro using the fibration $Gl(2n)/SO(2n) \to BSO(2n) \to BGl(2n)$ and a computation of the Chow ring of $Gl(2n)/SO(2n)$ in a previous paper. We find this Chow ring is generated ... More
Two-stack-sorting with pop stacksJan 15 2018Feb 01 2019We consider the set of permutations that are sorted after two passes through a pop stack. We characterize these permutations in terms of forbidden patterns (classical and barred) and enumerate them according to the ascent statistic. Then we show these ... More
Momentum conserving defects in affine Toda field theoriesDec 09 2016May 19 2017Type II integrable defects with more than one degree of freedom at the defect are investigated. A condition on the form of the Lagrangian for such defects is found which ensures the existence of a conserved momentum in the presence of the defect. In addition ... More
Wach modules, regulator maps, and epsilon-isomorphisms in familiesOct 31 2016Oct 23 2017We prove the local epsilon-isomorphism conjecture of Fukaya and Kato [FK06] for certain crystalline families of G_Qp-representations. This conjecture can be regarded as a local analogue of the Iwasawa main conjecture for families. Our work extends earlier ... More
The monoidal structure on strict polynomial functorsMar 17 2015The category of strict polynomial functors inherits an internal tensor product from the category of divided powers. To investigate this monoidal structure, we consider the category of representations of the symmetric group which admits a tensor product ... More
Lattice Designs in Standard and Simple Implicit Multi-linear RegressionMar 25 2016Statisticians generally use ordinary least squares to minimize the random error in a subject response with respect to independent explanatory variable. However, Wooten shows illustrates how ordinary least squares can be used to minimize the random error ... More
Cross-Newell equations for hexagons and trianglesOct 16 1999The Cross-Newell equations for hexagons and triangles are derived for general real gradient systems, and are found to be in flux-divergence form. Specific examples of complex governing equations that give rise to hexagons and triangles and which have ... More
Search strategies for developing characterizations of graphs without small wheel subdivisionsNov 04 2013Practical algorithms for solving the Subgraph Homeomorphism Problem are known for only a few small pattern graphs: among these are the wheel graphs with four, five, six, and seven spokes. The length and difficulty of the proofs leading to these algorithms ... More
The Warped Disc of NGC 4258Apr 07 2008We consider the properties of the warped accretion disc in NGC 4258 which is delineated by maser emission. We use our analytical models to consider whether the disc could be warped by Lense-Thirring precession. We show that such models fit the shape of ... More
An Improved Deterministic Rescaling for Linear Programming AlgorithmsDec 14 2016The perceptron algorithm for linear programming, arising from machine learning, has been around since the 1950s. While not a polynomial-time algorithm, it is useful in practice due to its simplicity and robustness. In 2004, Dunagan and Vempala showed ... More
Weighted hyperprojective spaces and homotopy invariance in orbifold cohomologyAug 16 2007We show that Chen-Ruan cohomology is a homotopy invariant in certain cases. We introduce the notion of a T-representation homotopy, which is a stringent form of homotopy under which Chen-Ruan cohomology is invariant. We show that while hyperkahler quotients ... More
Generalized twistor spaces for hyperkähler manifoldsSep 18 2013Let M be a hyperk\"ahler manifold. The S^2-family of complex structures compatible with the hyperk\"ahler metric can be assembled into a single complex structure on Z=MxS^2; the resulting complex manifold is known as the twistor space of M. We describe ... More
Targeted Syntactic Evaluation of Language ModelsAug 27 2018We present a dataset for evaluating the grammaticality of the predictions of a language model. We automatically construct a large number of minimally different pairs of English sentences, each consisting of a grammatical and an ungrammatical sentence. ... More