Results for "Rebecca L. Russell"

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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
Automated Vulnerability Detection in Source Code Using Deep Representation LearningJul 11 2018Nov 28 2018Increasing numbers of software vulnerabilities are discovered every year whether they are reported publicly or discovered internally in proprietary code. These vulnerabilities can pose serious risk of exploit and result in system compromise, information ... More
Ideological and Policy Origins of the Internet, 1957-1969Sep 24 2001Oct 25 2001This paper examines the ideological and policy consensus that shaped computing research funded by the Information Processing Techniques Office (IPTO) within the Department of Defense's Advanced Research Projects Agency (ARPA). This historical case study ... 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
On multiplicities of maximal weights of $\hat{sl}(n)$-modulesSep 19 2013We determine explicitly the maximal dominant weights for the integrable highest weight $\hat{sl}(n)$-modules $V((k-1)\Lambda_0 + \Lambda_s)$, $0 \leq s \leq n-1$, $ k \geq 2$. We give a conjecture for the number of maximal dominant weights of $V(k\Lambda_0)$ ... More
Snapshot fiber spectral imaging using speckle correlations and compressive sensingOct 24 2018Snapshot spectral imaging is rapidly gaining interest for remote sensing applications. Acquiring spatial and spectral data within one image promotes fast measurement times, and reduces the need for stabilized scanning imaging systems. Many current snapshot ... 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
Generic Misalignment Aberration Patterns and the Subspace of Benign MisalignmentJul 11 2012Q1: Why deploy N wavefront sensors on a three mirror anastigmat (TMA) and not N + 1? Q2: Why measure M Zernike coefficients and not M + 1? Q3: Why control L rigid body degrees of freedom (total) on the secondary and tertiary and not L + 1? The usual answer: ... 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
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
A new approach for detecting scientific specialties from raw cocitation networksJul 30 2008We use a technique recently developed by Blondel et al. (2008) in order to detect scientific specialties from author cocitation networks. This algorithm has distinct advantages over most of the previous methods used to obtain cocitation "clusters", since ... More
Automated software vulnerability detection with machine learningFeb 14 2018Aug 02 2018Thousands of security vulnerabilities are discovered in production software each year, either reported publicly to the Common Vulnerabilities and Exposures database or discovered internally in proprietary code. Vulnerabilities often manifest themselves ... More
On the Diagnostic Power of FIR/Sub-mm SED Fitting in Massive Galactic Molecular ClumpsOct 17 2018We used FIR and submillimeter continuum data from Herschel and the Atacama Pathfinder EXperiment (APEX) to fit pixel-by-pixel modified Planck SEDs to prestellar and protostellar clumps in the Census of High- and Medium-mass Protostars (CHaMP) ($280^{\circ}<\ell<300^{\circ}$, ... More
Deep Learning Enabled Real Time Speckle Recognition and Hyperspectral Imaging using a Multimode Fiber ArrayApr 07 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
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
SegICP-DSR: Dense Semantic Scene Reconstruction and RegistrationNov 06 2017To enable autonomous robotic manipulation in unstructured environments, we present SegICP-DSR, a real- time, dense, semantic scene reconstruction and pose estimation algorithm that achieves mm-level pose accuracy and standard deviation (7.9 mm, {\sigma}=7.6 ... More
Saltatory Relaxation of the Cosmological ConstantMay 30 2000Feb 28 2001We modify and extend an earlier proposal by Brown and Teitelboim to relax the effective cosmological term by nucleation of branes coupled to a three-index gauge potential. Microscopic considerations from string/M theory suggest two major innovations in ... More
Direct dialling of Haar random unitary matricesJun 20 2015Random unitary matrices find a number of applications in quantum information science, and are central to the recently defined boson sampling algorithm for photons in linear optics. We describe an operationally simple method to directly implement Haar ... 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
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
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
Approximate Dynamic Programming using Halfspace Queries and Multiscale Monge decompositionMar 25 2010Jul 03 2010Let $P=(P_1, P_2, \ldots, P_n)$, $P_i \in \field{R}$ for all $i$, be a signal and let $C$ be a constant. In this work our goal is to find a function $F:[n]\rightarrow \field{R}$ which optimizes the following objective function: $$ \min_{F} \sum_{i=1}^n ... 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
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
Twists and TwistabilityFeb 01 2018Metrically homogeneous graphs are connected graphs which, when endowed with the path metric, are homogeneous as metric spaces. In this paper we introduce the concept of twisted automorphisms, a notion of isomorphism up to a permutation of the language. ... 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.
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
Generalized Yang-Baxter Equations and Braiding Quantum GatesAug 26 2011Solutions to the Yang-Baxter equation - an important equation in mathematics and physics - and their afforded braid group representations have applications in fields such as knot theory, statistical mechanics, and, most recently, quantum information science. ... More
Reconstructing Merger Timelines Using Star Cluster Age Distributions: the Case of MCG+08-11-002Feb 02 2016We present near infrared imaging and integral field spectroscopy of the centre of the dusty luminous infrared galaxy merger MCG+08-11-002, taken using the Near InfraRed Camera 2 (NIRC2) and the OH-Suppressing InfraRed Imaging Spectrograph (OSIRIS) on ... 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
Evidence for Decay of Turbulence by MHD Shocks in Molecular Clouds via CO EmissionMay 04 2015We utilize observations of sub-millimeter rotational transitions of CO from a Herschel Cycle 2 open time program ("COPS", PI: J. Green) to identify previously predicted turbulent dissipation by magnetohydrodynamic (MHD) shocks in molecular clouds. We ... 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
A Comparison of Blocking Methods for Record LinkageJul 11 2014Record linkage seeks to merge databases and to remove duplicates when unique identifiers are not available. Most approaches use blocking techniques to reduce the computational complexity associated with record linkage. We review traditional blocking techniques, ... 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
Individuals, Institutions, and Innovation in the Debates of the French RevolutionOct 18 2017The French Revolution brought principles of "liberty, equality, and brotherhood" to bear on the day-to-day challenges of governing what was then the largest country in Europe. Its experiments provided a model for future revolutions and democracies across ... More
Relaxation volumes of microscopic and mesoscopic irradiation-induced defects in tungstenDec 17 2018The low energy structures of irradiation-induced defects have been studied in detail, as these determine the available modes by which a defect can diffuse or relax. As a result, there are many studies concerning the relative energies of possible defect ... More
Trouble With The Curve: Improving MLB Pitch ClassificationApr 05 2013The PITCHf/x database has allowed the statistical analysis of of Major League Baseball (MLB) to flourish since its introduction in late 2006. Using PITCHf/x, pitches have been classified by hand, requiring considerable effort, or using neural network ... More
Alignment of a circumbinary disc around an eccentric binary with application to KH 15DApr 01 2019We analyse the evolution of a mildly inclined circumbinary disc that orbits an eccentric orbit binary by means of smoother particle hydrodynamic (SPH) simulations and linear theory. We show that the alignment process of an initially misaligned circumbinary ... More
Line Emission in the Brightest Cluster Galaxies of the NOAO Fundamental Plane and Sloan Digital Sky SurveysApr 24 2007We examine the optical emission line properties of Brightest Cluster Galaxies (BCGs) selected from two large, homogeneous datasets. The first is the X-ray selected National Optical Astronomy Observatory Fundamental Plane Survey (NFPS), and the second ... 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
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.
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.
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.
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
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
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
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
Additive Separability, Optimization, and Trivial WebsJan 01 2009In this paper we show that two seemingly unrelated problems in economics, the hypothesis of integrability and the hypothesis of additive separability are linked by the absence of curvature of connections on webs naturally associated with each problem. ... More
Albanese varieties with modulus over a perfect fieldFeb 15 2009Oct 08 2013Let X be a smooth proper variety over a perfect field k of arbitrary characteristic. Let D be an effective divisor on X with multiplicity. We introduce an Albanese variety Alb(X, D) of X of modulus D as a higher dimensional analogon of the generalized ... More
A Simple Path to Biggins' Martingale Convergence for Branching Random WalkMar 23 1998We give a simple non-analytic proof of Biggins' theorem on martingale convergence for branching random walks.
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
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
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
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
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
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
Separating enhancement from loss: plasmonic nanocavities in the weak coupling regimeNov 01 2011By modifying the density of optical states at the location of an emitter, weak cavity-emitter coupling can enable a host of potential applications in quantum optics, from the development of low- threshold lasers to brighter single-photon sources for quantum ... More
Data Mining to Investigate the Meteorological Drivers for Extreme Ground Level Ozone EventsApr 30 2015Mar 11 2016This project aims to explore which combinations of meteorological conditions are associated with extreme ground level ozone conditions. Our approach focuses only on the tail by optimizing the tail dependence between the ozone response and functions of ... More
A new quadruple-image gravitational lens in an edge-on disk galaxy at z=0.0956Jun 18 2018We report the serendipitous discovery of a quadruply-lensed source behind the z=0.095 edge-on disk galaxy 2MASXJ13170000-1405187, based on public imaging survey data from Pan-STARRS PS1 and the VISTA Hemisphere Survey. Follow-up imaging from Magellan/LDSS3 ... More
Graham's Variety and Perverse Sheaves on the Nilpotent ConeNov 09 2011In recent work, Graham has constructed a variety with a map to the nilpotent cone which is similar in some ways to the Springer resolution. One aspect in which Graham's map differs is that it is not in general an isomorphism over the principal orbit, ... More
Comparing Graphs of Different SizesFeb 22 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
Fine-Grained Decision-Theoretic Search ControlMar 27 2013Decision-theoretic control of search has previously used as its basic unit. of computation the generation and evaluation of a complete set of successors. Although this simplifies analysis, it results in some lost opportunities for pruning and satisficing. ... 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
Szego limit theoremsMay 06 2002Sep 25 2002The first Szego limit theorem has been extended by Bump-Diaconis and Tracy-Widom to limits of other minors of Toeplitz matrices. We extend their results still further to allow more general measures and more general determinants. We also give a new extension ... More
Counting closed geodesics in a compact rank one locally CAT(0) spaceMar 18 2019Let $X$ be a compact, geodesically complete, locally CAT(0) space such that the universal cover admits a rank one axis. Assume $X$ is not homothetic to a metric graph with integer edge lengths. Let $P_t$ be the number of parallel classes of oriented closed ... 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
Ab initio Prediction of RNA Nucleotide Interactions with Backbone k-Tree ModelJul 26 2014Given the importance of non-coding RNAs to cellular regulatory functions and rapid growth of RNA transcripts, computational prediction of RNA tertiary structure remains highly demanded yet significantly challenging. Even for a short RNA sequence, the ... 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
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
Early-type galaxies in low-density environmentsJul 23 2002We describe the construction and study of an objectively-defined sample of early-type galaxies in low-density environments. The sample galaxies are selected from a recently-completed redshift survey using uniform and readily-quantified isolation criteria, ... More
Simulations of Titan's paleoclimateDec 26 2014We investigate the effects of varying Saturn's orbit on the atmospheric circulation and surface methane distribution of Titan. Using a new general circulation model of Titan's atmosphere, we simulate its climate under four characteristic configurations ... More
Online Data Thinning via Multi-Subspace TrackingSep 12 2016In an era of ubiquitous large-scale streaming data, the availability of data far exceeds the capacity of expert human analysts. In many settings, such data is either discarded or stored unprocessed in datacenters. This paper proposes a method of online ... More
Symmetry, Isotopy, and Irregular CoversSep 14 2013We say that a cover of surfaces S -> X has the Birman--Hilden property if the subgroup of the mapping class group of X consisting of mapping classes that have representatives that lift to S embeds in the mapping class group of S modulo the group of deck ... More
Regularized Non-Gaussian Image DenoisingAug 12 2015In image denoising problems, one widely-adopted approach is to minimize a regularized data-fit objective function, where the data-fit term is derived from a physical image acquisition model. Typically the regularizer is selected with two goals in mind: ... More
A stack and a pop stack in seriesMar 06 2013We study sorting machines consisting of a stack and a pop stack in series, with or without a queue between them. While there are, a priori, four such machines, only two are essentially different: a pop stack followed directly by a stack, and a pop stack ... More
Dual Filtered GraphsOct 28 2014May 02 2016We define a K-theoretic analogue of Fomin's dual graded graphs, which we call dual filtered graphs. The key formula in the definition is DU-UD= D + I. Our major examples are K-theoretic analogues of Young's lattice, of shifted Young's lattice, and of ... More
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
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.
Six Challenges for Neural Machine TranslationJun 12 2017We explore six challenges for neural machine translation: domain mismatch, amount of training data, rare words, long sentences, word alignment, and beam search. We show both deficiencies and improvements over the quality of phrase-based statistical machine ... 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
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
Load Balancing in Mobility-on-Demand Systems: Reallocation Via Parametric Control Using Concurrent EstimationApr 07 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
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
Emergent Ising degrees of freedom above double-stripe magnetismAug 14 2017Aug 22 2017Double-stripe magnetism $[\mathbf{Q}=(\pi/2, \pi/2)]$ has been proposed as the magnetic ground state for both the iron-telluride and BaTi$_2$Sb$_2$O families of superconductors. Double-stripe order is captured within a $J_1-J_2-J_3$ Heisenberg model in ... More
Pattern avoidance in permutations and their squaresDec 31 2018We study permutations $p$ so that both $p$ and $p^2$ avoid a given pattern $q$.
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
Word-Sense Disambiguation Using Decomposable ModelsJun 01 1994Most probabilistic classifiers used for word-sense disambiguation have either been based on only one contextual feature or have used a model that is simply assumed to characterize the interdependencies among multiple contextual features. In this paper, ... More
Principal Component Analysis: Resources for an Essential Application of Linear AlgebraApr 15 2016Principal Component Analysis (PCA) is a highly useful topic within an introductory Linear Algebra course, especially since it can be used to incorporate a number of applied projects. This method represents an essential application and extension of the ... More
Deformations of Lagrangian Type Submanifolds inside G2 manifoldsMar 10 20153-dimensional Harvey Lawson submanifolds were introduced in an earlier paper by Akbulut-Salur, as examples of Lagrangian-type manifolds inside G2 manifold. In this paper, we first show that the space of deformations of a smooth, compact, orientable Harvey-Lawson ... More
Analytic PSF Correction for Gravitational Flexion StudiesAug 28 2013May 23 2014Given a galaxy image, one cannot simply measure its flexion. An image's spin one and three shape properties, typically associated with F- and G-flexion, are actually complicated functions of the galaxy's intrinsic shape and the telescope's PSF, in addition ... More
An Involution on Involutions and a Generalization of Layered PermutationsMay 19 2016Apr 03 2019Taking transposes of Standard Young Tableaux defines a natural involution on the set $I(n)$ of involutions of length $n$ via the the Robinson-Schensted correspondence. In some cases, this involution can be defined without resorting to the Robinson-Schensted ... More
Orbifold cohomology of hypertoric varietiesJul 18 2006Oct 14 2007Hypertoric varieties are hyperk\"ahler analogues of toric varieties, and are constructed as abelian hyperk\"ahler quotients of a quaternionic affine space. Just as symplectic toric orbifolds are determined by labelled polytopes, orbifold hypertoric varieties ... More
Survival of a recessive allele in a Mendelian diploid modelMay 08 2015Aug 23 2016In this paper we analyse the genetic evolution of a diploid hermaphroditic population, which is modelled by a three-type nonlinear birth-and-death process with competition and Mendelian reproduction. In a recent paper, Collet et al., 2013 have shown that, ... More
Transitive permutation groups with trivial four point stabilizersNov 27 2014In this paper we analyze the structure of transitive permutation groups that have trivial four point stabilizers, but some nontrivial three point stabilizer. In particular we give a complete, detailed classification when the group is simple or quasisimple. ... More
Greene--Kleitman invariants for Sulzgruber insertionAug 31 2017R. Sulzgruber's rim hook insertion and the Hillman-Grassl correspondence are two distinct bijections between the reverse plane partitions of a fixed partition shape and multisets of rim-hooks of the same partition shape. It is known that Hillman-Grassl ... More
An Involution on Involutions and a Generalization of Layered PermutationsMay 19 2016Taking transposes of Standard Young Tableaux defines a natural involution on the set $I(n)$ of involutions of length $n$ via the the Robinson-Schensted correspondence. In some cases, this involution can be defined without resorting to the Robinson-Schensted ... More
Bridgeland stability conditions on surfaces with curves of negative self-intersectionFeb 21 2017Aug 27 2018Let $X$ be a smooth complex projective variety. In 2002, Bridgeland defined a notion of stability for the objects in $D^b(X)$, the bounded derived category of coherent sheaves on $X$, which generalized the notion of slope stability for vector bundles ... More