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Results for "Alex K. Lew"

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Few-Shot Bayesian Imitation Learning with Logic over ProgramsApr 12 2019We describe an expressive class of policies that can be efficiently learned from a few demonstrations. Policies are represented as logical combinations of programs drawn from a small domain-specific language (DSL). We define a prior over policies with ... More
Spectral gaps of simplicial complexes without large missing facesJun 01 2017Let $X$ be a simplicial complex on $n$ vertices without missing faces of dimension larger than $d$. Let $L_{j}$ denote the $j$-Laplacian acting on real $j$-cochains of $X$ and let $\mu_{j}(X)$ denote its minimal eigenvalue. We study the connection between ... More
Collapsibility of simplicial complexes of hypergraphsOct 28 2018Let $\mathcal{H}$ be a hypergraph of rank $r$. We show that the simplicial complex whose simplices are the hypergraphs $\mathcal{F}\subset\mathcal{H}$ with covering number at most $p$ is $\left(\binom{r+p}{r}-1\right)$-collapsible, and the simplicial ... More
Spectral gaps, missing faces and minimal degreesJul 04 2018Let $X$ be a simplicial complex with $n$ vertices. A missing face of $X$ is a simplex $\sigma\notin X$ such that $\tau\in X$ for any $\tau\subsetneq \sigma$. For a $k$-dimensional simplex $\sigma$ in $X$, its degree in $X$ is the number of $(k+1)$-dimensional ... More
To P or not to P: on the evidential nature of P-values and their place in scientific inferenceNov 01 2013The customary use of P-values in scientific research has been attacked as being ill-conceived, and the utility of P-values has been derided. This paper reviews common misconceptions about P-values and their alleged deficits as indices of experimental ... More
Baryogenesis through Collapsing String Loops in Gauged Baryon and Lepton ModelsJun 30 1993A scenario for the generation of the baryon asymmetry in the early Universe is proposed in which cosmic string loops, predicted by theories where the baryon and/or lepton numbers are gauged symmetries, collapse during the friction dominated period of ... More
Precision in ground based solar polarimetry: Simulating the role of adaptive opticsNov 02 2012Accurate measurement of polarization in spectral lines is important for the reliable inference of magnetic fields on the Sun. For ground based observations, polarimetric precision is severely limited by the presence of Earth's atmosphere. Atmospheric ... More
The likelihood principle does not entail a `sure thing', `evil demon' or `determinist' hypothesisJul 30 2015Aug 24 2015The likelihood principle makes strong claims about the nature of statistical evidence but is controversial. Its claims are undermined by the existence of several examples that are assumed to show that it allows, with unity probability, domination of all ... More
Binary and nonbinary description of hypointensity in human brain MR imagesDec 31 2010Accumulating evidence has shown that iron is involved in the mechanism underlying many neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and Huntington's disease. Abnormal (higher) iron accumulation has been detected in the ... More
Static and Dynamic Properties of Type-II Composite Fermion Wigner CrystalsJun 10 2011The Wigner crystal of composite fermions is a strongly correlated state of complex emergent particles, and therefore its unambiguous detection would be of significant importance. Recent observation of optical resonances in the vicinity of filling factor ... More
Entropic Topological Invariants in Three DimensionsApr 11 2015We evaluate the entanglement entropy of exactly solvable Hamiltonians corresponding to general families of three-dimensional topological models. We show that the modification to the entropic area law due to three-dimensional topological properties is ... More
Galactic Outflows by Alfvénic Poynting Flux: Application to Fermi BubblesOct 11 2017Jan 19 2018We investigate roles of magnetic activity in the Galactic bulge region in driving large-scale outflows of size $\sim 10$ kpc. Magnetic buoyancy and breakups of channel flows formed by magnetorotational instability excite Poynting flux by the magnetic ... More
Clear sky atmosphere at cm-wavelengths from climatology dataMay 31 2015Oct 29 2015We utilise ground-based, balloon-borne and satellite climatology data to reconstruct site and season-dependent vertical profiles of precipitable water vapour (PWV). We use these profiles to solve radiative transfer through the atmosphere, and derive atmospheric ... More
Universal Meshes: A new paradigm for computing with nonconforming triangulationsJan 24 2012We describe a method for discretizing planar C2-regular domains immersed in non-conforming triangulations. The method consists in constructing mappings from triangles in a background mesh to curvilinear ones that conform exactly to the immersed domain. ... More
Analysis of a method to parameterize planar curves immersed in triangulationsSep 16 2011Feb 17 2013We prove that a planar $C^2$-regular boundary $\Gamma$ can always be parameterized with its closest point projection $\pi$ over a certain collection of edges $\Gamma_h$ in an ambient triangulation, by making simple assumptions on the background mesh. ... More
Finer-grained Locking in Concurrent Dynamic Planar Convex HullsFeb 09 2017The convex hull of a planar point set is the smallest convex polygon containing each point in the set. The dynamic convex hull problem concerns efficiently maintaining the convex hull of a set of points subject to additions and removals. One algorithm ... More
Reconstructing comptonization parameters using simulations of single frequency, dual-beam observations of galaxy clustersAug 11 2016Aug 12 2016Systematical effects in dual-beam, differential, radio observations of extended objects are discussed in the context of the One Centimeter Receiver Array (OCRA). We use simulated samples of Sunyaev--Zel'dovich (SZ) galaxy clusters at low ($z<0.4$) and ... More
Fundamental Limits on Measuring the Rotational Constraint of Single Molecules using Fluorescence MicroscopyNov 22 2018Optical fluorescence imaging is capable of measuring both the spatial and rotational dynamics of single molecules. However, unavoidable measurement noise will result in inaccurate estimates of rotational dynamics, causing a molecule to appear to be more ... More
Introducing interdisciplinary science to second year undergraduates in a Current Topics in Biophysics courseApr 24 2015We offer second year students the opportunity to explore Current Topics in Biophysics in a course co-taught by a physicist and a biologist. The interdisciplinary course allows university students to engage in analytical thinking that integrates physics ... More
Quark-Lepton SymmetryNov 20 1992Quark-lepton symmetric models are a class of gauge theories motivated by the similarities between the quarks and leptons. In these models the gauge group of the standard model is extended to include a ``color'' group for the leptons. Consequently, the ... More
Variational integrators for the dynamics of thermo-elastic solids with finite speed thermal wavesMar 15 2014This paper formulates variational integrators for finite element discretizations of deformable bodies with heat conduction in the form of finite speed thermal waves. The cornerstone of the construction consists in taking advantage of the fact that the ... More
A test of the Poincare dodecahedral space topology hypothesis with the WMAP CMB dataJan 09 2008Apr 24 2008It has been suggested by Roukema and coworkers (hereafter R04) that the topology of the Universe as probed by the ``matched circles'' method using the first year release of the WMAP CMB data, might be that of the Poincar\'e dodecahedral space (PDS) model. ... More
Dynamic Feature Description in Human Action RecognitionDec 31 2010This work aims to present novel description methods for human action recognition. Generally, a video sequence can be represented as a collection of spatial temporal words by detecting space-time interest points and describing the unique features around ... More
The route to high temperature superconductivity in transition metal oxidesOct 07 2010The discovery of high temperature superconductivity in cuprates was possible only through an intimate knowledge of perovskite oxides which have been synthesized and characterized for decades at the IBM in the Z\"urich laboratoty. Especially SrTiO3 and ... More
Algorithms for Replica Placement in High-Availability StorageMar 09 2015May 22 2015A new model of causal failure is presented and used to solve a novel replica placement problem in data centers. The model describes dependencies among system components as a directed graph. A replica placement is defined as a subset of vertices in such ... More
Crossover behavior in a mixed mode fiber bundle modelMay 19 2004Dec 06 2004We introduce a mixed-mode load sharing scheme in fiber bundle model. This model reduces exactly to equal load sharing (ELS) and local load sharing (LLS) models at the two extreme conditions of the load sharing rule. We identify two distinct regimes: a) ... More
Lexico-minimum Replica Placement in MultitreesSep 17 2017In this work, we consider the problem of placing replicas in a data center or storage area network, represented as a digraph, so as to lexico-minimize a previously proposed reliability measure which minimizes the impact of all failure events in the model ... More
Algorithms for Optimal Replica Placement Under Correlated Failure in Hierarchical Failure DomainsJan 06 2017Apr 20 2017In data centers, data replication is the primary method used to ensure availability of customer data. To avoid correlated failure, cloud storage infrastructure providers model hierarchical failure domains using a tree, and avoid placing a large number ... More
Pair-Starved Pulsar MagnetospheresOct 16 2008We propose a simple analytic model for the innermost (within the light cylinder of canonical radius) structure of open-magnetic-field lines of a rotating neutron star (NS) with relativistic outflow of charged particles (electrons/positrons) and arbitrary ... More
Particle Acceleration in Pair-Starved PulsarsAug 20 2004We investigate the physical situation above the pulsar polar cap (PC) where the accelerating primaries (electrons) are not capable of producing sufficient numbers of electron-positron pairs at low altitudes (within 1-2 stellar radii above the PC surface) ... More
Failure Processes in Elastic Fiber BundlesAug 09 2008Jul 17 2009The fiber bundle model describes a collection of elastic fibers under load. the fibers fail successively and for each failure, the load distribution among the surviving fibers change. Even though very simple, the model captures the essentials of failure ... More
A Framework for Real-Time Face and Facial Feature Tracking using Optical Flow Pre-estimation and Template TrackingDec 31 2010This work presents a framework for tracking head movements and capturing the movements of the mouth and both the eyebrows in real-time. We present a head tracker which is a combination of a optical flow and a template based tracker. The estimation of ... More
High-Order Finite Element Methods for Moving Boundary Problems with Prescribed Boundary EvolutionMay 08 2014We introduce a framework for the design of finite element methods for two-dimensional moving boundary problems with prescribed boundary evolution that have arbitrarily high order of accuracy, both in space and in time. At the core of our approach is the ... More
Supercloseness of Orthogonal Projections onto Nearby Finite Element SpacesAug 18 2014We derive upper bounds on the difference between the orthogonal projections of a smooth function $u$ onto two finite element spaces that are nearby, in the sense that the support of every shape function belonging to one but not both of the spaces is contained ... More
Spatial mapping of band bending in semiconductor devices using in-situ quantum sensorsSep 13 2018Band bending is a central concept in solid-state physics that arises from local variations in charge distribution especially near semiconductor interfaces and surfaces. Its precision measurement is vital in a variety of contexts from the optimisation ... More
Model for a Light Z' BosonJan 13 1994A model of a light $Z'$ boson is constructed and phenomenological bounds are derived. This $Z'$ boson arises from a very simple extension to the Standard Model, and it is constrained to be light because the vacuum expectation values which generate its ... More
Dynamics of a nanowire superlattice in an ac electric fieldSep 24 2005With a one-band envelope function theory, we investigate the dynamics of a finite nanowire superlattice driven by an ac electric field by solving numerically the time-dependent Schroedinger equation. We find that for an ac electric field resonant with ... More
Proof-graphs for Minimal Implicational LogicApr 01 2014It is well-known that the size of propositional classical proofs can be huge. Proof theoretical studies discovered exponential gaps between normal or cut free proofs and their respective non-normal proofs. The aim of this work is to study how to reduce ... More
Quantification of spin accumulation causing spin-orbit torque in Pt/Co/Ta stackAug 04 2017Spin accumulation induced by spin-orbit coupling is experimentally quantified in stack with in-plane magnetic anisotropy via the contribution of spin accumulation to Hall resistances. Using a biasing direct current the spin accumulation within the structure ... More
Self-assembly of monodisperse clusters: Dependence on target geometryJul 28 2009We apply a simple model system of patchy particles to study monodisperse self-assembly, using the Platonic solids as target structures. We find marked differences between the assembly behaviours of the different systems. Tetrahedra, octahedra and icosahedra ... More
Multi-Task Time Series Analysis applied to Drug Response ModellingMar 21 2019Time series models such as dynamical systems are frequently fitted to a cohort of data, ignoring variation between individual entities such as patients. In this paper we show how these models can be personalised to an individual level while retaining ... More
Twistor variables for Anti-de Sitter (super)particlesAug 15 2016Starting from the classical action for a spin-zero particle in a (D + 1)-dimensional anti-Sitter spacetime, we recover the Breitenlohner-Freedman bound by quantization. We then find a twistor form of the action for D = 3, 4, 6 for which the SO(2, D) isometry ... More
Anti-de Sitter particles and manifest (super)isometriesAug 15 2016Oct 07 2016Starting from the classical action for a spin-zero particle in a D-dimensional anti-Sitter (AdS) spacetime, we recover the Breitenlohner-Freedman bound by quantization. For D=4,5,7 we find a simple bi-twistor form of the action; the AdS isometry group ... More
Mitigating Wordline Crosstalk using Adaptive Trees of CountersJun 07 2018High access frequency of certain rows in the DRAM may cause data loss in cells of physically adjacent rows due to crosstalk. The malicious exploit of this crosstalk by repeatedly accessing a row to induce this effect is known as row hammering. Additionally, ... More
Thermodynamics of statistical inference by cellsMay 15 2014Oct 06 2014The deep connection between thermodynamics, computation, and information is now well established both theoretically and experimentally. Here, we extend these ideas to show that thermodynamics also places fundamental constraints on statistical estimation ... More
Light propagation in biaxial crystalsFeb 24 2015May 19 2015We present a formalism able to predict the transformation of light beams passing through biaxial crystals. We use this formalism to show both theoretically and experimentally the transition from double refraction to conical refraction, which is found ... More
A Physical Model-based Correction for Charge Traps in the Hubble Space Telescope's Wide Field Camera 3 Near-IR Detector and Applications to Transiting Exoplanets and Brown DwarfsMar 03 2017Mar 16 2017The Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) near-IR channel is extensively used in time-resolved observations, especially for transiting exoplanet spectroscopy and brown dwarf and directly imaged exoplanet rotational phase mapping. The ... More
High-Energy Emission From Millisecond PulsarsNov 30 2004The X-ray and gamma-ray spectrum of rotation-powered millisecond pulsars is investigated in a model for acceleration and pair cascades on open field lines above the polar caps. Although these pulsars have low surface magnetic fields, their short periods ... More
Quantitative characterization of spin-orbit torques in Pt/Co/Pt /Co/Ta/BTO heterostructure on the magnetization azimuthal angle dependenceJun 06 2017Substantial understanding of spin-orbit interactions in heavy-metal (HM)/ferromagnet (FM) heterostructures is crucial in developing spin-orbit torque (SOT) spintronics devices utilizing spin Hall and Rashba effects. Though the study of SOT effective fields ... More
A First-Quantized Formalism for Cosmological Particle ProductionNov 19 2003May 12 2004We show that the amount of particle production in an arbitrary cosmological background can be determined using only the late-time positive-frequency modes. We don't refer to modes at early times, so there is no need for a Bogolubov transformation. We ... More
Spectrally-accurate quadratures for evaluation of layer potentials close to the boundary for the 2D Stokes and Laplace equationsOct 08 2014Dense particulate flow simulations using integral equation methods demand accurate evaluation of Stokes layer potentials on arbitrarily close interfaces. In this paper, we generalize techniques for close evaluation of Laplace double-layer potentials in ... More
Keldysh technique and non-linear sigma-model: basic principles and applicationsJan 23 2009Apr 27 2009The purpose of this review is to provide a comprehensive pedagogical introduction into Keldysh technique for interacting out-of-equilibrium fermionic and bosonic systems. The emphasis is placed on a functional integral representation of underlying microscopic ... More
Universal Meshes for the Simulation of Brittle Fracture and Moving Boundary ProblemsOct 17 2015Universal meshes have recently appeared in the literature as a compu- tationally efficient and robust paradigm for the generation of conforming simpli- cial meshes for domains with evolving boundaries. The main idea behind a univer- sal mesh is to immerse ... More
A big-world network in ASD: Dynamical connectivity analysis reflects a deficit in long-range connections and an excess of short-range connectionsJul 30 2010Over the last years, increasing evidence has fuelled the hypothesis that Autism Spectrum Disorder (ASD) is a condition of altered brain functional connectivity. The great majority of these empirical studies rely on functional magnetic resonance imaging ... More
Moving NRQCD and B to K* gammaOct 16 2007The formulation of NRQCD discretized in a reference frame boosted relative to the B rest frame will enable calculation of B form factors over a larger range of momentum transfer. We have initiated a program to calculate form factors describing the rare ... More
An Electrochemical Potentiostat Interface for Mobile Devices: Enabling Remote Medical DiagnosticsSep 29 2015An electrochemical potentiostat interface for mobile devices has been designed and implemented. The interface consists of a potentiostat module, a microcontroller module, and a Bluetooth module. The potentiostat module performs electrochemical measurements ... More
Rare B decays with moving NRQCD and improved staggered quarksOct 06 2008We calculate form factors relevant for rare B decays using moving-NRQCD for the b quark and the AsqTad action for the light quarks. Moving NRQCD allows us to work directly with the physical b quark mass and go to higher recoil momentum compared to standard ... More
Learned Video CompressionNov 16 2018We present a new algorithm for video coding, learned end-to-end for the low-latency mode. In this setting, our approach outperforms all existing video codecs across nearly the entire bitrate range. To our knowledge, this is the first ML-based method to ... More
Strain-induced energy band gap opening in two-dimensional bilayered silicon filmSep 01 2015This work presents a theoretical study of the structural and electronic properties of bilayered silicon films under in-plane biaxial strain/stress using density functional theory. Atomic structures of the two-dimensional silicon films are optimized by ... More
The effect of topology on the structure and free energy landscape of DNA kissing complexesMar 15 2012We use a recently developed coarse-grained model for DNA to study kissing complexes formed by hybridization of complementary hairpin loops. The binding of the loops is topologically constrained because their linking number must remain constant. By studying ... More
The Impact of Galactic Disc Environment on Star-Forming CloudsDec 04 2017We explore the effect of different galactic disc environments on the properties of star-forming clouds through variations in the background potential in a set of isolated galaxy simulations. Rising, falling and flat rotation curves expected in halo dominated, ... More
Augmenting adaptive immunity: progress and challenges in the quantitative engineering and analysis of adaptive immune receptor repertoiresApr 08 2019Apr 09 2019The adaptive immune system is a natural diagnostic and therapeutic. It recognizes threats earlier than clinical symptoms manifest and neutralizes antigen with exquisite specificity. Recognition specificity and broad reactivity is enabled via adaptive ... More
Tight Bounds on the Weighted Sum of MMSEs with Applications in Distributed EstimationFeb 20 2019In this paper, tight upper and lower bounds are derived on the weighted sum of minimum mean-squared errors for additive Gaussian noise channels. The bounds are obtained by constraining the input distribution to be close to a Gaussian reference distribution ... More
Wide optical spectrum range, sub-volt, compact modulator based on electro-optic polymer refilled silicon slot photonic crystal waveguideMar 01 2014We design and demonstrate a compact and low-power band-engineered electro-optic (EO) polymer refilled silicon slot photonic crystal waveguide (PCW) modulator. The EO polymer is engineered for large EO activity and near-infrared transparency. A PCW step ... More
Emerging from The Cloud: A Bibliometric Analysis of Cloud Forensics StudiesJul 27 2018The emergence of cloud computing technologies has changed the way we store, retrieve, and archive our data. With the promise of unlimited, reliable and always-available storage, a lot of private and confidential data are now stored on different cloud ... More
Augmenting adaptive immunity: progress and challenges in the quantitative engineering and analysis of adaptive immune receptor repertoiresApr 08 2019The adaptive immune system is a natural diagnostic and therapeutic. It recognizes threats earlier than clinical symptoms manifest and neutralizes antigen with exquisite specificity. Recognition specificity and broad reactivity is enabled via adaptive ... More
Robust Neighbor Discovery in Multi-Hop Multi-Channel Heterogeneous Wireless NetworksMay 01 2015Mar 02 2016An important first step when deploying a wireless ad hoc network is neighbor discovery in which every node attempts to determine the set of nodes it can communicate with in one wireless hop. In the recent years, cognitive radio (CR) technology has gained ... More
Capacity Lower Bounds of the Noncentral Chi-Channel with Applications to Soliton Amplitude ModulationSep 08 2016Feb 16 2018The channel law for amplitude-modulated solitons transmitted through a nonlinear optical fibre with ideal distributed amplification and a receiver based on the nonlinear Fourier transform is a noncentral chi-distribution with $2n$ degrees of freedom, ... More
A Lower Bound on the per Soliton Capacity of the Nonlinear Optical Fibre ChannelAug 19 2015Aug 21 2015A closed-form expression for a lower bound on the per soliton capacity of the nonlinear optical fibre channel in the presence of (optical) amplifier spontaneous emission (ASE) noise is derived. This bound is based on a non-Gaussian conditional probability ... More
Direct observation of surface state thermal oscillation in SmB6 oscillatorsDec 17 2017SmB6 is a mixed valence Kondo insulator that exhibits a sharp increase in resistance following an activated behavior that levels off and saturates below 4K. This behavior can be explained by the proposal of SmB6 representing a new state of matter, a Topological ... More
Performance and Stability of the Chelonia Storage CloudFeb 03 2010In this paper we present the Chelonia storage cloud middleware. It was designed to fill the requirements gap between those of large, sophisticated scientific collaborations which have adopted the grid paradigm for their distributed storage needs, and ... More
Topological Brain Network DistancesSep 09 2018Existing brain network distances are often based on matrix norms. The element-wise differences in the existing matrix norms may fail to capture underlying topological differences. Further, matrix norms are sensitive to outliers. A major disadvantage to ... More
Exotic Bilayer Crystals in a Strong Magnetic FieldMar 23 2018Jun 27 2018Electron bilayers in a strong magnetic field exhibit insulating behavior for a wide range of interlayer separation $d$ for total Landau level fillings $\nu\leq 1/2$, which has been interpreted in terms of a pinned crystal. We study theoretically the competition ... More
Miniaturized Low-power Electro-optic Modulator Based on Silicon Integrated Nanophotonics and Organic PolymersDec 08 2014We design and demonstrate a compact, low-power, low-dispersion and broadband optical modulator based on electro-optic (EO) polymer refilled silicon slot photonic crystal waveguide (PCW). The EO polymer is engineered for large EO activity and near-infrared ... More
What Makes Social Search EfficientApr 13 2019The idea of the small world first put forth by Milgram in the 1960's shows empirically how people knowing reliably only connections to their direct contacts can leverage their knowledge to perform an efficient global search, referred to as social search, ... More
A Hint of Poincaré Dodecahedral Topology in the WMAP First Year Sky MapFeb 25 2004Jun 03 2004Luminet et al. (2003) suggested that WMAP data are better matched by a Poincar\'e dodecahedral FLRW model of global geometry, rather than by an infinite flat model. The analysis by Cornish et al. (2003) for angular radii 25-90 degrees failed to support ... More
A Lower Bound on the Capacity of the Noncentral Chi Channel with Applications to Soliton Amplitude ModulationSep 08 2016The channel law for amplitude-modulated solitons transmitted through a nonlinear optical fibre with ideal distributed amplification and a receiver based on the nonlinear Fourier transform is a noncentral chi distribution with $2n$ degrees of freedom, ... More
Quantum control of population transfer between vibrational states in an optical latticeOct 30 2015We study quantum control techniques, specifically Adiabatic Rapid Passage (ARP) and Gradient Ascent Pulse Engineering (GRAPE), for transferring atoms trapped in an optical lattice between different vibrational states. We compare them with each other and ... More
Dense Super-Resolution Imaging of Molecular Orientation via Joint Sparse Basis Deconvolution and Spatial PoolingJan 12 2019In single-molecule super-resolution microscopy, engineered point-spread functions (PSFs) are designed to efficiently encode new molecular properties, such as 3D orientation, into complex spatial features captured by a camera. To fully benefit from their ... More
Computing stress intensity factors for curvilinear cracksJan 14 2015The use of the interaction integral to compute stress intensity factors around a crack tip requires selecting an auxiliary field and a material variation field. We formulate a family of these fields accounting for the curvilinear nature of cracks that, ... More
Ensemble of Convolutional Neural Networks for Automatic Grading of Diabetic Retinopathy and Macular EdemaSep 12 2018In this manuscript, we automate the procedure of grading of diabetic retinopathy and macular edema from fundus images using an ensemble of convolutional neural networks. The availability of limited amount of labeled data to perform supervised learning ... More
Portfolio Optimization Under UncertaintyAug 11 2009Sep 21 2009Classical mean-variance portfolio theory tells us how to construct a portfolio of assets which has the greatest expected return for a given level of return volatility. Utility theory then allows an investor to choose the point along this efficient frontier ... More
Ł-Axiomatizability in intermediate and normal modal logicsJul 22 2014A set $F$ of formulas is complete relative to a given class of logics, if every logic from this class can be axiomatized by formulas from $F$. A set of formulas $F$ is {\L}-complete relative to a given class of logics, if every logic of this class can ... More
Sequence Transduction with Recurrent Neural NetworksNov 14 2012Many machine learning tasks can be expressed as the transformation---or \emph{transduction}---of input sequences into output sequences: speech recognition, machine translation, protein secondary structure prediction and text-to-speech to name but a few. ... More
Transition-Based Dependency Parsing With Pluggable ClassifiersNov 01 2012In principle, the design of transition-based dependency parsers makes it possible to experiment with any general-purpose classifier without other changes to the parsing algorithm. In practice, however, it often takes substantial software engineering to ... More
There are no noncommutative soft mapsFeb 02 2011It is shown that for a map $f \colon X \to Y$ of compact spaces the unital $\ast$-homomorphism $C(f) \colon C(Y) \to C(X)$ is projective in the category $\operatorname{Mor}({\mathcal C}^{1})$ precisely when $X$ is a dendrite and $f$ is either homeomorphism ... More
Effective Action of the Baryonic Branch in String Theory Flux ThroatsMay 07 2014Sep 12 2014We discuss consistent truncations of type IIB supergravity on resolved warped deformed conifolds with fluxes. These actions represent the gravitational duals to the baryonic branch deformation of the Klebanov-Strassler cascading gauge theory. As an application, ... More
On jet quenching parameters in strongly coupled non-conformal gauge theoriesMay 18 2006Aug 02 2006Recently Liu, Rajagopal and Wiedemann (LRW) [hep-ph/0605178] proposed a first principle, nonperturbative quantum field theoretic definition of ``jet quenching parameter'' \hat{q} used in models of medium-induced radiative parton energy loss in nucleus-nucleus ... More
Higher derivative corrections to near-extremal black holes in type IIB supergravityApr 24 2006Jun 08 2006We discuss string theory alpha' corrections to charged near-extremal black 3-branes/black holes in type IIB supergravity. We find that supersymmetric global AdS_5 x S^5 geometry is not corrected to leading order in alpha', while charged or non-extremal ... More
Inflation on the resolved warped deformed conifoldJan 01 2006Aug 10 2006Braneworld inflation on the resolved warped deformed conifold is represented by the dynamics of a D3-brane probe with the world volume of a brane spanning the large dimensions of the observable Universe. This model was recently proposed as a string theory ... More
Coarse-graining 1/2 BPS geometries of type IIB supergravitySep 26 2004Recently Lin, Lunin and Maldacena (LLM) (hep-th/0409174) explicitly mapped 1/2 BPS excitations of type IIB supergravity on AdS_5 x S^5 into free fermion configurations. We discuss thermal coarse-gaining of LLM geometries by explicitly mapping the corresponding ... More
Gauge/gravity correspondence in accelerating universeMar 06 2002Apr 16 2002We discuss time-dependent backgrounds of type IIB supergravity realizing gravitation duals of gauge theories formulated in de Sitter space-time as a tool of embedding de Sitter in a supergravity. We show that only the gravitational duals to non-conformal ... More
Instantons and singularities in the Yang-Mills flowFeb 13 2014Oct 11 2016Several results on existence and convergence of the Yang-Mills flow in dimension four are given. We show that a singularity modeled on an instanton cannot form within finite time. Given low initial self-dual energy, we then study convergence of the flow ... More
Continuous homomorphisms of Arens-Michael algebrasAug 15 1999Feb 19 2000It is shown that every continuous homomorphism of Arens-Michael algebras can be obtained as the limit of a morphism of certain projective systems consisting of Fr\'{e}chet algebras. Based on this we prove that a complemented subalgebra of an uncountable ... More
The Automorphisms group of \bar{M}_{g,n}Oct 07 2011Let \bar{\mathcal{M}}_{g,n}$ be the moduli stack parametrizing Deligne-Mumford stable n-pointed genus g curves and let \bar{M}_{g,n} be its coarse moduli space: the Deligne-Mumford compactification of the moduli space of n-pointed genus g smooth curves. ... More
Linear Time Average Consensus on Fixed Graphs and Implications for Decentralized Optimization and Multi-Agent ControlNov 15 2014May 23 2016We describe a protocol for the average consensus problem on any fixed undirected graph whose convergence time scales linearly in the total number nodes $n$. The protocol is completely distributed, with the exception of requiring all nodes to know the ... More
Magnetization suppression of Type-II Superconductors by external alternating magnetic fieldDec 27 2004The effect of suppression of static magnetization of an anisotropic hard superconductor by alternating magnetic field is analyzed theoretically. The magnetic moment suppression dynamics is described with respect to the magnetization loop of the superconductor. ... More
Recent Results From CLEO-cMay 23 2005This paper describes recent preliminary results from the CLEO-c experiment using an initial ~60 pb^-1 sample of data collected in e^+e^- collisions at a center of mass energy around the mass of the psi(3770). A first measurement of the branching fraction ... More
Orbit equivalence rigidityNov 01 1999Consider a countable group Gamma acting ergodically by measure preserving transformations on a probability space (X,mu), and let R_Gamma be the corresponding orbit equivalence relation on X. The following rigidity phenomenon is shown: there exist group ... More
A multivariate CLT in Wasserstein distance with near optimal convergence rateFeb 17 2016Let $X_1, \ldots , X_n$ be i.i.d. random vectors in $\mathbb{R}^d$ with $\|X_1\| \le \beta$. Then, we show that $\frac{1}{\sqrt{n}}(X_1 + \ldots + X_n)$ converges to a Gaussian in Wasserstein-2 distance at a rate of $O\left(\frac{\sqrt{d} \beta \log n}{\sqrt{n}} ... More