Results for "SeYoung Yun"

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Non-Stationary Streaming PCAFeb 08 2019We consider the problem of streaming principal component analysis (PCA) when the observations are noisy and generated in a non-stationary environment. Given $T$, $p$-dimensional noisy observations sampled from a non-stationary variant of the spiked covariance ... More
Convergence Rates of Gradient Descent and MM Algorithms for Generalized Bradley-Terry ModelsJan 01 2019We show tight convergence rate bounds for gradient descent and MM algorithms for maximum likelihood estimation and maximum aposteriori probability estimation of a popular Bayesian inference method for generalized Bradley-Terry models. This class of models ... More
Non-Stationary Streaming PCAFeb 08 2019Mar 30 2019We consider the problem of streaming principal component analysis (PCA) when the observations are noisy and generated in a non-stationary environment. Given $T$, $p$-dimensional noisy observations sampled from a non-stationary variant of the spiked covariance ... More
Spin-Polarized to Valley-Polarized Transition in Graphene Bilayers at $ν=0$ in High Magnetic FieldsFeb 01 2011Jul 04 2011We investigate the transverse electric field ($E$) dependence of the $\nu$=0 quantum Hall state (QHS) in dual-gated graphene bilayers in high magnetic fields. The longitudinal resistivity ($\rho_{xx}$) measured at $\nu$=0 shows an insulating behavior ... More
Modeling Waveform Shapes with Random Eects Segmental Hidden Markov ModelsJul 11 2012In this paper we describe a general probabilistic framework for modeling waveforms such as heartbeats from ECG data. The model is based on segmental hidden Markov models (as used in speech recognition) with the addition of random effects to the generative ... More
Dielectric Thickness Dependence of Carrier Mobility in Graphene with HfO2 Top DielectricOct 05 2010We investigate the carrier mobility in mono- and bi-layer graphene with a top HfO2 dielectric, as a function of the HfO2 film thickness and temperature. The results show that the carrier mobility decreases during the deposition of the first 2-4 nm of ... More
Attribute And-Or Grammar for Joint Parsing of Human Attributes, Part and PoseMay 06 2016Jul 07 2016This paper presents an attribute and-or grammar (A-AOG) model for jointly inferring human body pose and human attributes in a parse graph with attributes augmented to nodes in the hierarchical representation. In contrast to other popular methods in the ... More
Large-Scale Optimization Algorithms for Sparse Conditional Gaussian Graphical ModelsSep 15 2015Dec 26 2015This paper addresses the problem of scalable optimization for L1-regularized conditional Gaussian graphical models. Conditional Gaussian graphical models generalize the well-known Gaussian graphical models to conditional distributions to model the output ... More
Coulomb Drag and Magnetotransport in Graphene Double LayersJun 13 2012We review the fabrication and key transport properties of graphene double layers, consisting of two graphene monolayers placed in close proximity, independently contacted, and separated by an ultra-thin dielectric. We outline a simple band structure model ... More
Feature Selection via Block-Regularized RegressionJun 13 2012Identifying co-varying causal elements in very high dimensional feature space with internal structures, e.g., a space with as many as millions of linearly ordered features, as one typically encounters in problems such as whole genome association (WGA) ... More
Tree-guided group lasso for multi-response regression with structured sparsity, with an application to eQTL mappingSep 08 2009Sep 28 2012We consider the problem of estimating a sparse multi-response regression function, with an application to expression quantitative trait locus (eQTL) mapping, where the goal is to discover genetic variations that influence gene-expression levels. In particular, ... More
Conditional Ergodic Averages for Asymptotically Additive PotentialsMay 07 2014Using an asymptotically additive sequence of continuous functions as a restrictive condition, this paper studies the relations of several ergodic averages for asymptotically additive potentials. Basic properties of conditional maximum ergodic averages ... More
One New Blowup Criterion for the 2D Full Compressible Navier-Stokes SystemOct 24 2012Jan 30 2013We establish a blowup criterion for the two-dimensional (2D) full compressible Navier-Stokes system. The criterion is given in terms of the divergence of the velocity field only, and is independent of the temperature. It is almost the same as that of ... More
Small Quarkonium states in an anisotropic QCD plasmaMay 16 2008We determine the hard-loop resummed propagator in an anisotropic QCD plasma in general covariant gauges and define a potential between heavy quarks from the Fourier transform of its static limit. We find that the potential exhibits angular dependence ... More
Testing 5d-6d dualities with fractional D-branesJul 26 20166d SCFTs compactified on a circle can often be studied from nonperturbative 5d super-Yang-Mills theories, using instanton solitons. However, the 5d Yang-Mills theories with 6d UV fixed points frequently have too many hypermultiplet matters, which makes ... More
Two types of electric field enhancements by infinitely many circular conductors arranged closely in two parallel lineDec 14 2016Apr 16 2017In this paper, we consider very high concentration of electric field in between infinitely many circular perfect conductors arranged closely in two rows. In stiff fiber-reinforced composite, shear stress concentrations occur in between neighboring fibers, ... More
Using Logistic Regression to Analyze the Balance of a Game: The Case of StarCraft IIMay 04 2011Recently, the market size of online game has been increasing astonishingly fast, and so does the importance of good game design. In online games, usually a human user competes with others, so the fairness of the game system to all users is of great importance ... More
Toroidal AdS Charged Branes and Toda EquationsOct 15 2009In this note, we consider the equations of motion for charged branes in AdS space and show that they can be cast into one-dimensional coupled Toda type. Then we solve the equations of motion to construct static charged AdS brane solutions which are invariant ... More
Brane Solutions with TensionMay 27 2009Nov 09 2009In this note, we apply a special metric ansatz to simplify the equations of motion for gravitational systems. Then we construct charged brane solutions in $D=n+p+2$ dimensions which have spherical symmetry of $S^n$ and translational symmetry along $p$ ... More
Non-Supersymmetric Unattractors in Born-Infeld Black HolesJun 14 2007We investigate unattractor behavior in non-extremal black holes in Einstein-Born-Infeld-Dilaton theory of gravity in four-dimensional asymptotically flat spacetime. We obtain solutions which are non-singular near the horizon and dependent on the value ... More
Orbital integrals and Dedekind zeta functionsMar 11 2013Mar 12 2013Let F be a local non-archimedean field. We prove a formula relating orbital integrals in GL(n,F) (for the unit Hecke function) and the generating series counting ideals of a certain ring. Using this formula, we give an explicit estimate for such orbital ... More
Motives with exceptional Galois groups and the inverse Galois problemDec 12 2011We construct motivic $\ell$-adic representations of $\GQ$ into exceptional groups of type $E_7,E_8$ and $G_2$ whose image is Zariski dense. This answers a question of Serre. The construction is uniform for these groups and uses the Langlands correspondence ... More
Higher-order Alexander Invariants of Hypersurface ComplementsOct 12 2015We define the higher-order Alexander modules $A_{n,i}(\mathcal{U})$ and higher-order degrees $\delta_{n,i}(\mathcal{U})$ which are invariants of a complex hypersurface complement $\mathcal{U}$. These invariants come from the module structure of the homology ... More
Observational approaches to understanding dark energyDec 01 2007Illuminating the nature of dark energy is one of the most important challenges in cosmology today. In this review I discuss several promising observational approaches to understanding dark energy, in the context of the recommendations by the U.S. Dark ... More
Differentiating dark energy and modified gravity with galaxy redshift surveysOct 21 2007Apr 28 2008The observed cosmic acceleration today could be due to an unknown energy component (dark energy), or a modification to general relativity (modified gravity). If dark energy models and modified gravity models are required to predict the same cosmic expansion ... More
Modeling galaxy clustering on small scales to tighten constraints on dark energy and modified gravityJun 26 2016Oct 10 2016We present a new approach to measuring cosmic expansion history and growth rate of large scale structure using the anisotropic two dimensional galaxy correlation function (2DCF) measured from data; it makes use of the empirical modeling of small-scale ... More
Lectures on Springer theories and orbital integralsFeb 03 2016These are the expanded lecture notes from the author's mini-course during the graduate summer school of the Park City Math Institute in 2015. The main topics covered are: geometry of Springer fibers, affine Springer fibers and Hitchin fibers; representations ... More
Parallelism-Aware Memory Interference Delay Analysis for COTS Multicore SystemsJul 25 2014In modern Commercial Off-The-Shelf (COTS) multicore systems, each core can generate many parallel memory requests at a time. The processing of these parallel requests in the DRAM controller greatly affects the memory interference delay experienced by ... More
Dynamics of a generalized Beverton-Holt competition model subject to Allee effectsMay 21 2015We propose and study {a generalized Beverton-Holt competition model} subject to Allee effects to obtain insights on how the interplay of Allee effects and contest competition affects the persistence and the extinction of two competing species. By using ... More
Galois representations attached to moments of Kloosterman sums and conjectures of EvansAug 19 2013Sep 07 2013Kloosterman sums for a finite field arise as Frobenius trace functions of certain local systems defined over $\Gm$. The moments of Kloosterman sums calculate the Frobenius traces on the cohomology of tensor powers (or symmetric powers, exterior powers, ... More
The spherical part of the local and global Springer actionsJun 11 2011The affine Weyl group acts on the cohomology (with compact support) of affine Springer fibers (local Springer theory) and of parabolic Hitchin fibers (global Springer theory). In this paper, we show that in both situations, the action of the center of ... More
Towards a Global Springer Theory I: The affine Weyl group actionOct 13 2008Apr 22 2009We propose a generalization of Springer representations to the context of groups over a global function field. The global counterpart of the Grothendieck simultaneous resolution is the parabolic Hitchin fibration. We construct an action of the affine ... More
125 GeV Higgs bosons in two-Higgs-doublet modelsMay 14 2013Moriond 2013 ALTAS data at 125 GeV state appears to exhibit a substantial excess in the di-photon final state and in the ZZ decaying to four lepton channel, whereas which are more or less SM-like rate observed by CMS MVA analysis. We examine the maximum ... More
Matrix Models for Deconfinement and Their Perturbative CorrectionsSep 23 2014Nov 27 2014Matrix models for the deconfining phase transition in $SU(N)$ gauge theories have been developed in recent years. With a few parameters, these models are able to reproduce the lattice results of the thermodynamic quantities in the semi-quark gluon plasma(QGP) ... More
Observational Probes of Dark EnergyJan 10 2012Jan 12 2012The cause for the observed acceleration in the expansion of the universe is unknown, and referred to as "dark energy" for convenience. Dark energy could be an unknown energy component, or a modification of Einstein's general relativity. This dictates ... More
Gluon Propagator and Heavy Quark Potential in an Anisotropic QCD PlasmaSep 23 2008The hard-loop resummed propagator in an anisotropic QCD plasma in general linear gauges are computed. We get the explicit expressions of the gluon propagator in covariant gauge, Coulomb gauge and temporal axial gauge. Considering one gluon exchange, the ... More
Many worlds interpretation for double slit experimentMay 29 2014As is well known, the double slit experiment contains every key concepts of quantum mechanics such as phase effect, probability wave, quantum interference, quantum superposition. In this article, I will clarify the meaning of quantum superposition in ... More
Path integral approach on Schrodinger's catOct 30 2013Jan 24 2014From the following thought experiments, it is demonstrated that the collapse of wave function of an isolated system is possible without external observer. It will be shown that the analysis by Feynman path integral method supports this conclusion. The ... More
An optimal estimate for electric fields on the shortest line segment between two spherical insulators in three dimensionsApr 28 2015Dec 13 2015We consider a gradient estimate for a conductivity problem whose inclusions are two neighboring insulators in three dimensions. When inclusions with an extreme conductivity (insulators or perfect conductors) are closely located, the gradient can be concentrated ... More
Domain Walls in AdS-Einstein-scalar GravityDec 19 2010Apr 26 2011In this note, we will show that the supergravity theory which is dual to ABJM field theory can be consistently reduced to scalar-coupled AdS-Einstein gravity and then consider the reflection symmetric domain wall and its small fluctuation. This domain ... More
Epipelagic representations and rigid local systemsJan 29 2014We construct automorphic representations for quasi-split groups $G$ over the function field $F=k(t)$ one of whose local components is an epipelagic representation in the sense of Reeder and Yu. We also construct the attached Galois representations under ... More
Higher signs for Coxeter groupsAug 10 2019We define and study cocycles on a Coxeter group in each degree generalizing the sign function. When the Coxeter group is a Weyl group, we explain how the degree three cocycle arises naturally from geometry representation theory.
Figure of Merit for Dark Energy Constraints from Current Observational DataMar 31 2008Choosing the appropriate figure of merit (FoM) for dark energy (DE) constraints is key in comparing different DE experiments. Here we show that for a set of DE parameters {f_i}, it is most intuitive to define FoM = 1/\sqrt{Cov(f1,f2,f3,...)}, where Cov(f1,f2,f3,...) ... More
Model-Independent Distance Measurements from Gamma-Ray Bursts and Constraints on Dark EnergySep 03 2008Dec 16 2008Gamma-Ray Bursts (GRB) are the most energetic events in the Universe, and provide a complementary probe of dark energy by allowing the measurement of cosmic expansion history that extends to redshifts greater than 6. Unlike Type Ia supernovae (SNe Ia), ... More
Reducts of the random bipartite graphJan 10 2011Aug 18 2011Let $\Gamma$ be the random bipartite graph, a countable graph with two infinite sides, edges randomly distributed between the sides, but no edges within a side. In this paper, we investigate the reducts of $\Gamma$ that preserve sides. We classify the ... More
Model-Independent Measurements of Cosmic Expansion and Growth at z=0.57 Using the Anisotropic Clustering of CMASS Galaxies From the Sloan Digital Sky Survey Data Release 9Apr 21 2014Jul 07 2014We analyze the anisotropic two dimensional galaxy correlation function (2DCF) of the CMASS galaxy sample from the Sloan Digital Sky Survey Data Release 9 (DR9) of the Baryon Oscillation Spectroscopic Survey (BOSS) data. Modeling the 2DCF fully including ... More
A Tale Of Two Amplitudes In High Energy PhysicsMay 27 2013(abbreviated) I will describe my work on proton Compton scattering in a Unified Proton-Delta theory and on the computation of scattering amplitudes in Yang-Mills theory. We study proton Compton scattering in the first resonance region in an effective ... More
The Frenet-Serret formulas of a discrete centroaffine curveJan 25 2016In this paper, we build the fundamental theory of a discrete centroaffine curve. For a discrete plane curve, we define its first and second centroaffine curvatures which are invariant under the affine transformation. Using the centroaffine curvatures, ... More
Space time symmetry in quantum mechanicsFeb 26 2014Mar 12 2014New prescription to treat position and time equally in quantum mechanics is presented. Using this prescription, we could successfully derive some interesting formulae such as time-of-arrival for a free particle and quantum tunneling formula. The physical ... More
The effects of Zn Impurity on the Properties of Doped Cuprates in the Normal StateMay 14 2004We study the interplay of quantum impurity, and collective spinon and holon dynamics in Zn doped high-T$_c$ cuprates in the normal state. The two-dimensional t-t$^{\prime}$-J models with one and a small amount of Zn impurity are investigated within a ... More
Moving frame and integrable system of the discrete centroaffine curves in R^3Jan 25 2016Nov 27 2016Any two equivalent discrete curves must have the same invariants at the corresponding points under an affine transformation. In this paper, we construct the moving frame and invariants for the discrete centroaffine curves, which could be used to discriminate ... More
Permanence of a general discrete-time two-species-interaction model with non-monotonic per capita growth ratesFeb 28 2011Combined with all density-dependent factors, the per capita growth rate of a species may be non-monotonic. One important consequence is that species may suffer from weak Allee effects or strong Allee effects. In this paper, we study the permanence of ... More
Towards a Global Springer Theory II: the double affine actionApr 22 2009We construct an action of the graded double affine Hecke algebra (DAHA) on the parabolic Hitchin complex, extending the affine Weyl group action constructed in \cite{GSI}. In particular, we get representations of the degenerate DAHA on the cohomology ... More
Horseshoes for $\mathcal{C}^{1+α}$ mappings with hyperbolic measuresNov 25 2014We present here a construction of horseshoes for any $\mathcal{C}^{1+\alpha}$ mapping $f$ preserving an ergodic hyperbolic measure $\mu$ with $h_{\mu}(f)>0$ and then deduce that the exponential growth rate of the number of periodic points for any $\mathcal{C}^{1+\alpha}$ ... More
Towards a Global Springer Theory III: Endoscopy and Langlands dualityApr 22 2009We prove three new results about the global Springer action defined in \cite{GSI}. The first one determines the support of the perverse cohomology sheaves of the parabolic Hitchin complex, which serves as a technical tool for the next results. The second ... More
The fundamental lemma of Jacquet-Rallis in positive characteristicsJan 07 2009Oct 28 2009We prove both the group version and the Lie algebra version of the Fundamental Lemma appearing in a relative trace formula of Jacquet-Rallis in the function field case when the characteristic is greater than the rank of the relevant groups.
Weights of mixed tilting sheaves and geometric Ringel dualityMay 10 2008Nov 22 2008We describe several general methods for calculating weights of mixed tilting sheaves. We introduce a notion called "non-cancellation property" which implies a strong uniqueness of mixed tilting sheaves and enables one to calculate their weights effectively. ... More
Orientation data for local P2Sep 06 2018In this note, we show that the canonical orientation data on the quiver hearts are compatible under the autoequivalence $\_\otimes\pi^*O(1)$, and hence glue to give an orientation data for the stack of coherent sheaves on local P2.
Meaning of delayed choice experiment and quantum uncertaintyApr 22 2014By slight modifying of the delayed-choice experiment, it is argued that the quantum wave function must be interpreted as real physical entity; With this interpretation in mind, multiple least action paths due to uncertainty leads us to new perspective ... More
Robust constraints on dark energy and gravity from galaxy clustering dataFeb 23 2012Apr 24 2012Galaxy clustering data provide a powerful probe of dark energy. We examine how the constraints on the scaled expansion history of the universe, x_h(z)=H(z)s (with s denoting the sound horizon at the drag epoch), and the scaled angular diameter distance, ... More
Reducts of the Generalized Random Bipartite GraphJul 20 2011Let \Gamma be the generalized random bipartite graph that has two sides Rl and Rr with edges for every pair of vertices between R1 and Rr but no edges within each side, where all the edges are randomly colored by three colors P1; P2; P3. In this paper, ... More
Distance Measurements from Supernovae and Dark Energy ConstraintsOct 14 2009Nov 10 2009Constraints on dark energy from current observational data are sensitive to how distances are measured from Type Ia supernova (SN Ia) data. We find that flux-averaging of SNe Ia can be used to test the presence of unknown systematic uncertainties, and ... More
Clarifying Forecasts of Dark Energy Constraints from Baryon Acoustic OscillationsApr 14 2009Dec 03 2009The measurement of baryon acoustic oscillations (BAO) from a galaxy redshift survey provides one of the most promising methods for probing dark energy. In this paper, we clarify the assumptions that go into the forecasts of dark energy constraints from ... More
On the Hessian of Shape Matching EnergyApr 08 2016Apr 13 2016In this technical report we derive the analytic form of the Hessian matrix for shape matching energy. Shape matching is a useful technique for meshless deformation, which can be easily combined with multiple techniques in real-time dynamics. Nevertheless, ... More
Discrete Time Harness ProcessesJun 06 2015Jun 09 2015We study the invariant measures and fluctuation limits of discrete-time harness processes in one spatial dimension. We construct one essential ergodic (under spatial shifts) invariant measure of the increment process derived from harness process, and ... More
Rigidity in automorphic representations and local systemsMay 13 2014We introduce the notion of rigidity for automorphic representations of groups over global function fields. We construct the Langlands parameters of rigid automorphic representations explicitly as local systems over open curves. We expect these local systems ... More
Hitchin type moduli stacks in automorphic representation theorySep 06 2018In the study of automorphic representations over a function field, Hitchin moduli stack and its variants naturally appear and their geometry helps the comparison of trace formulae. We give a survey on applications of this observation to a relative fundamental ... More
Livšic Measurable Rigidity Theorem for \mathcal{C}^1 Generic Volume-preserving SystemsOct 31 2014In this paper, we prove that for $\mathcal{C}^1$ generic volume-preserving Anosov diffeomorphisms of a compact Riemannian manifold, Liv\v{s}ic measurable rigidity theorem holds. We also prove that for $\mathcal{C}^1$ generic volume-preserving Anosov flows ... More
Non-separable covariance models for spatio-temporal data, with applications to neural encoding analysisMay 15 2017Neural encoding studies explore the relationships between measurements of neural activity and measurements of a behavior that is viewed as a response to that activity. The coupling between neural and behavioral measurements is typically imperfect and ... More
Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper FoilsMay 11 2009May 13 2009Graphene has been attracting great interest because of its distinctive band structure and physical properties. Today, graphene is limited to small sizes because it is produced mostly by exfoliating graphite. We grew large-area graphene films of the order ... More
Equivalence and Strong Equivalence between Sparsest and Least $\ell_1$-Norm Nonnegative Solutions of Linear Systems and Their ApplicationDec 15 2013Many practical problems can be formulated as l0-minimization problems with nonnegativity constraints, which seek the sparsest nonnegative solutions to underdetermined linear systems. Recent study indicates that l1-minimization is efficient for solving ... More
Ward Identity Implies Recursion Relation at Tree and Loop LevelJul 15 2012Feb 09 2013In this article, we use Ward identity to calculate tree and one loop level off shell amplitudes in pure Yang-Mills theory with a pair of external lines complexified. We explicitly prove Ward identity at tree and one loop level using Feynman rules, and ... More
Galaxy cluster angular size data constraints on dark energyMay 27 2011Jul 20 2011We use angular size versus redshift data for galaxy clusters from Bonamente et al. (2006) to place constraints on model parameters of constant and time-evolving dark energy cosmological models. These constraints are compatible with those from other recent ... More
Instability of a Kerr black hole in f(R) gravitySep 13 2013Nov 05 2013We study the stability of a rotating (Kerr) black hole in the viable $f(R)$ gravity. The linearized-Ricci scalar equation shows the superradiant instability, leading to the instability of the Kerr black hole in $f(R)$ gravity.
Modulation of electron carrier density at the n-type LaAlO3/SrTiO3 interface by water adsorptionMar 18 2013We investigate energetic stability and dissociation dynamics of water adsorption at the LaAlO3 surface of the n-type LaAlO3/SrTiO3 (LAO/STO) interface and its effect on electronic properties of the interface by carrying out first-principles electronic ... More
Van Dam-Veltman-Zakharov discontinuity in topologically new massive gravityDec 31 2012We study van Dam-Veltman-Zakharov discontinuity in the topologically new massive gravity (TNMG). The reduction from 2 degrees of freedom to one is interpreted as van Dam-Veltman-Zakharov discontinuity appeared when going from anti-de Sitter spacetime ... More
Area spectrum of slowly rotating black holesMar 18 2010Mar 24 2010We investigate the area spectrum for rotating black holes which are Kerr and BTZ black holes. For slowly rotating black holes, we use the Maggiore's idea combined with Kunstatter's method to derive their area spectra, which are equally spaced.
Entropic force in the presence of black holeFeb 04 2010We derive the entropic force in the presence of the Schwarzschild black hole by using the local equipartition rule and holographic principle. On the other hand, when using the Tolman temperature, one does not arrive at the Newtonian force law.
Logarithmic corrections to entropy for black holes with hyperbolic horizonAug 01 2008Jan 29 2009We compute logarithmic corrections to entropy for black holes with hyperbolic horizon. For this purpose, we introduce the topological black hole and MTZ black holes in four dimensions, while in five dimensions, the topological black holes and Gauss-Bonnet ... More
Lifshitz black holes in the Hořava-Lifshitz gravityFeb 24 2010Jun 03 2010We investigate the Lifshitz black holes from the Ho\v{r}ava-Lifshitz gravity by comparing with the Lifshitz black hole from the 3D new massive gravity. We note that these solutions all have single horizons. These black holes are very similar to each other ... More
Generalized uncertainty principle, quantum gravity and Hořava-Lifshitz gravitySep 11 2009Sep 29 2009We investigate a close connection between generalized uncertainty principle (GUP) and deformed Ho\v{r}ava-Lifshitz (HL) gravity. The GUP commutation relations correspond to the UV-quantum theory, while the canonical commutation relations represent the ... More
Phase transition between non-extremal and extremal Reissner-Nordström black holesOct 12 2007Mar 11 2008We discuss the phase transition between non-extremal and extremal Reissner-Nordstr\"om black holes. This transition is considered as the $T \to 0$ limit of the transition between the non-extremal and near-extremal black holes. We show that an evaporating ... More
Adiabatic Spectra During Slowly EvolvingDec 13 2010Jun 23 2011In general, for single field, the scale invariant spectrum of curvature perturbation can be given by either its constant mode or its increasing mode. We show that during slowly expanding or contracting, the spectrum of curvature perturbation given by ... More
On Primordial Density Perturbation and Decaying Speed of SoundJul 21 2008Mar 28 2009The decaying speed of sound can lead to the emergence of the primordial density perturbation in any expanding phase, even if the expansion is decelerated. Recently, some proposals have been given to implement this mechanism, in which it was found that ... More
Possible Explanation to Low CMB QuadrupoleFeb 17 2005Apr 26 2005The universe might experience many cycles with different vacua. The slow-roll inflation may be preceded by kinetic-dominated contraction occurring in "adjacent" vacua during some cycles. In this report we briefly show this phenomenon may lead to a cutoff ... More
Non-Gaussianity in Island CosmologyJul 24 2008Apr 24 2009In this paper we fully calculate the non-Gaussianity of primordial curvature perturbation of island universe by using the second order perturbation equation. We find that for the spectral index $n_s\simeq 0.96$, which is favored by current observations, ... More
Nearly Divergence of Correlation Length and Perturbation Spectrum in String Gas CosmologyFeb 02 2007Feb 08 2007Recently, it has been shown in Ref.[1] that the string thermodynamic fluctuation may lead to a scale invariant spectrum of scalar metric perturbation. However, its realization is still in study. In this note we suppose that the correlation length of metric ... More
Uncorrelated Measurements of the Cosmic Expansion History and Dark Energy from SupernovaeJan 18 2005May 13 2005We present a method for measuring the cosmic expansion history H(z) in uncorrelated redshift bins, and apply it to current and simulated type Ia supernova data assuming spatial flatness. If the matter density parameter Omega_m can be accurately measured ... More
New dark energy constraints from supernovae, microwave background and galaxy clusteringMar 11 2004Apr 23 2004Using the spectacular new high redshift supernova observations from the HST/GOODS program and previous supernova, CMB and galaxy clustering data, we make the most accurate measurements to date of the dark energy density rho_X as a function of cosmic time, ... More
Realization of the N(odd)-dimensional Quantum Euclidean Space by Differential OperatorsNov 03 2003The quantum Euclidean space R_{q}^{N} is a kind of noncommutative space which is obtained from ordinary Euclidean space R^{N} by deformation with parameter q. When N is odd, the structure of this space is similar to R_{q}^{3}. Motivated by realization ... More
Parabolic Constructions of Asymptotically Flat 3-metrics of Prescribed Scalar CurvatureDec 04 2012In 1993, Bartnik introduced a quasi-spherical construction of metrics of prescribed scalar curvature on 3-manifolds. Under quasi-spherical ansatz, the problem is converted into the initial value problem for a semi-linear parabolic equation of the lapse ... More
Robust designs to model uncertainty with high estimation and prediction efficiencyApr 13 2016Alphabetic optimality criteria, such as the $D$, $A$, and $I$ criteria, require specifying a model to select optimal designs. They are not model free and the optimal designs selected by them are not robust to model uncertainty. Recently, many extensions ... More
Connectionist Temporal Localization for Sound Event Detection with Sequential LabelingOct 22 2018Oct 27 2018Research on sound event detection (SED) with weak labeling has mostly focused on presence/absence labeling, which provides no temporal information at all about the event occurrences. In this paper, we consider SED with sequential labeling, which specifies ... More
Two-loop QCD effective potential in a constant background fieldOct 31 2018In this paper, we compute the QCD effective potential in a constant (classical) background $A^{{\rm cl}}_0$ up to two-loop order with finite quark mass and chemical potential. We present the explicit calculation by using the double line notation and analytical ... More
A quantized Tits-Kantor-Koecher algebraAug 22 2008We propose a quantum analogue of a Tits-Kantor-Koecher algebra with a Jordan torus as an coordinated algebra by looking at the vertex operator construction over a Fock space.
Model-Independent Constraints on Dark Energy Density from Flux-averaging Analysis of Type Ia Supernova DataDec 08 2003Jan 26 2004We reconstruct the dark energy density $\rho_X(z)$ as a free function from current type Ia supernova (SN Ia) data (Tonry et al. 2003; Barris et al. 2003; Knop et al. 2003), together with the Cosmic Microwave Background (CMB) shift parameter from CMB data ... More
Hanson-Wright inequality in Hilbert spaces with application to $K$-means clustering for non-Euclidean dataOct 26 2018We derive a dimensional-free Hanson-Wright inequality for quadratic forms of independent sub-gaussian random variables in a separable Hilbert space. Our inequality is an infinite-dimensional generalization of the classical Hanson-Wright inequality for ... More
The Vlasov-Maxwell-Boltzmann System for Weakly Inhomogeneous DataOct 13 2011May 06 2012This paper is devoted to the study of the dynamics of charged particles in a weakly inhomogeneous dilute gas. More precisely, we consider the existence of unique global in time classical solutions for the Vlasov-MaxwellBoltzmann system and its asymptotic ... More
Realizations of BC_r graded intersection matrix algebras with grading subalgebras of type B_r, $r \geq 3$Apr 16 2009Jan 10 2010We study intersection matrix algebras im(A^d) that arise from affinizing a Cartan matrix A of type B_r with d arbitrary long roots in the root system $\Delta_{B_r}$, where $r \geq 3$. We show that im(A^d) is isomorphic to the universal covering algebra ... More
Band-aid for information loss from black holesSep 04 2010Dec 20 2010We summarize, simplify and extend recent work showing that small deviations from exact thermality in Hawking radiation, first uncovered by Kraus and Wilczek, have the capacity to carry off the maximum information content of a black hole. This goes a considerable ... More