Results for "Sandra S. Y. Tan"

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Analysis of Optimization Algorithms via Sum-of-SquaresJun 11 2019In this work, we introduce a new framework for unifying and systematizing the performance analysis of first-order black-box optimization algorithms for unconstrained convex minimization over finite-dimensional Euclidean spaces. The low-cost iteration ... More
HBT Interferometry for Sonoluminescence BubbleDec 18 1996The two-photon correlation of the light pulse emitted from a sonoluminescence bubble is discussed. It is shown that several important information about the mechanism of light emission, such as the time-scale and the shape of the emission region could ... More
Wave Energy Amplification in a Metamaterial based Traveling Wave StructureMar 28 2010We consider the interaction between a particle beam and a propagating electromagnetic wave in the presence of a metamaterial. We show that the introduction of a metamaterial gives rise to a novel dispersion curve which determines a unique wave particle ... More
HBT Interferometry: Historical PerspectiveDec 27 2004Feb 17 2005I review the history of HBT interferometry, since its discovery in the mid 1950's, up to the recent developments and results from BNL/RHIC experiments. I focus the discussion on the contributions to the subject given by members of our Brazilian group. ... More
Phi-Phi Back-to-Back Correlations in Finite Expanding SystemsOct 20 2005Back-to-Back Correlations (BBC) of particle-antiparticle pairs are predicted to appear if hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. The BBC are related to in-medium mass-modification and squeezing of the quanta ... More
Multidimensional analysis of Bose-Einstein correlations in pp collisions at 2.76 and 7 TeV in CMSFeb 20 2015Multidimensional two-particle Bose-Einstein correlation functions of charged hadrons are reported for pp collisions at 2.76 and 7 TeV in terms of different components of the pair relative momentum, extending the previous one-dimensional (1-D) analyses ... More
Possible Origin of RHIC R_{out}/R_{sid} HBT ResultsSep 19 2002The effects of opacity of the nuclei together with a blackbody type of emission along the system history are considered as a means to explain the ratio $R_{out}/R_{sid}$ observed by STAR and PHENIX collaborations at RHIC. Within our model, no flow is ... More
Transport spectroscopy in a time-modulated open quantum dotOct 02 2002Jul 27 2005We have investigated the time-modulated coherent quantum transport phenomena in a ballistic open quantum dot. The conductance $G$ and the electron dwell time in the dots are calculated by a time-dependent mode-matching method. Under high-frequency modulation, ... More
Squeezed Fermions at Relativistic Heavy Ion CollidersJun 05 2000Mar 19 2001Large back-to-back correlations of observable fermion -- anti-fermion pairs are predicted to appear, if the mass of the fermions is modified in a thermalized medium. The back-to-back correlations of protons and anti-protons are experimentally observable ... More
Disappearance of Squeezed Back-to-Back Correlations - a new signal of hadron freeze-out from a supercooled Quark Gluon PlasmaJun 28 2007We briefly discuss four different possible types of transitions from quark to hadronic matter and their characteristic signatures in terms of correlations. We also highlight the effects arising from mass modification of hadrons in hot and dense hadronic ... More
R_{out}/R_{sid} and Opacity at RHICMay 08 2002Nov 18 2002One of the most dramatic results from the first RHIC run are the STAR results for pi+- pi+- interferometry. They showed that the ratio of the so-called R_{out} and R_{sid} radii seem to decrease below unity for increasing transverse momentum of the pair ... More
Back-to-Back Correlations for Finite Expanding FireballsDec 21 2005Back-to-Back Correlations of particle-antiparticle pairs are related to the in-medium mass-modification and squeezing of the quanta involved. They are predicted to appear when hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. ... More
Survival of Back-to-Back Correlations for Finite Expanding FireballsOct 20 2005Nov 04 2005Back-to-Back Correlations (BBC) of particle-antiparticle pairs are predicted to appear if hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. The BBC correlations are related to in-medium mass-modification and squeezing ... More
Constraining warm dark matter mass with cosmic reionization and gravitational waveJul 13 2016We constrain the warm dark matter (WDM) particle mass with the observations of cosmic reionization and CMB optical depth. We suggest that the GWs from stellar mass black holes (BHs) could give a further constraint on WDM particle mass for future observations. ... More
High-Dimensional Gaussian Graphical Model Selection: Walk Summability and Local Separation CriterionJul 06 2011Mar 04 2012We consider the problem of high-dimensional Gaussian graphical model selection. We identify a set of graphs for which an efficient estimation algorithm exists, and this algorithm is based on thresholding of empirical conditional covariances. Under a set ... More
Learning Gaussian Tree Models: Analysis of Error Exponents and Extremal StructuresSep 28 2009Jan 05 2010The problem of learning tree-structured Gaussian graphical models from independent and identically distributed (i.i.d.) samples is considered. The influence of the tree structure and the parameters of the Gaussian distribution on the learning rate as ... More
Learning High-Dimensional Markov Forest Distributions: Analysis of Error RatesMay 05 2010Feb 13 2011The problem of learning forest-structured discrete graphical models from i.i.d. samples is considered. An algorithm based on pruning of the Chow-Liu tree through adaptive thresholding is proposed. It is shown that this algorithm is both structurally consistent ... More
Hilbert Statistics of Vorticity Scaling in Two-Dimensional TurbulenceJan 16 2014In this paper, the scaling property of the inverse energy cascade and forward enstrophy cascade of the vorticity filed $\omega(x,y)$ in two-dimensional (2D) turbulence is analyzed. This is accomplished by applying a Hilbert-based technique, namely Hilbert-Huang ... More
Dust Depletion and Extinction in a Gamma-Ray Burst AfterglowJun 21 2004Sep 01 2004We put stringent constraints for the first time on the dust properties in the circumburst medium of a gamma-ray burst (GRB) afterglow. This is based on the optical spectrum of GRB 020813 (z=1.255), obtained with Keck I LRIS 4.65 h after the burst. From ... More
Resolving Power of 2-D Pion InterferometryJan 30 1995A $\chi^2$ analysis is performed to test the resolving power of two-dimensional pion interferometry using for illustration the preliminary E802 data on $Si+Au$ at 14.6 AGeV/c. We find that the resolving power to distinguish two decoupling geometries of ... More
A Formula for the Capacity of the General Gel'fand-Pinsker ChannelOct 03 2012Apr 16 2014We consider the Gel'fand-Pinsker problem in which the channel and state are general, i.e., possibly non-stationary, non-memoryless and non-ergodic. Using the information spectrum method and a non-trivial modification of the piggyback coding lemma by Wyner, ... More
On Dispersions of Discrete Memoryless Channels with Noncausal State Information at the EncoderApr 02 2012Nov 12 2013In this paper, we study the finite blocklength limits of state-dependent discrete memoryless channels where the discrete memoryless state is known noncausally at the encoder. For the point-to-point case, this is known as the Gel'fand-Pinsker channel model. ... More
Error and Erasure Exponents for the Broadcast Channel with Degraded Message SetsJan 27 2015Error and erasure exponents for the broadcast channel with degraded message sets are analyzed. The focus of our error probability analysis is on the main receiver where, nominally, both messages are to be decoded. A two-step decoding algorithm is proposed ... More
On the Reliability Function of the Discrete Memoryless Relay ChannelApr 12 2013Dec 23 2014Bounds on the reliability function for the discrete memoryless relay channel are derived using the method of types. Two achievable error exponents are derived based on partial decode-forward and compress-forward which are well-known superposition block-Markov ... More
Moderate-Deviations of Lossy Source Coding for Discrete and Gaussian SourcesNov 09 2011May 10 2012We study the moderate-deviations (MD) setting for lossy source coding of stationary memoryless sources. More specifically, we derive fundamental compression limits of source codes whose rates are $R(D) \pm \epsilon_n$, where $R(D)$ is the rate-distortion ... More
Asymptotic Estimates in Information Theory with Non-Vanishing Error ProbabilitiesApr 10 2015This monograph presents a unified treatment of single- and multi-user problems in Shannon's information theory where we depart from the requirement that the error probability decays asymptotically in the blocklength. Instead, the error probabilities for ... More
Structure, Magnetic Properties and Spin-glass Behavior in La$sub{0.9}Tesub{0.1}MnOsub{3}$Jan 21 2003In this study we report the structure, magnetic and electrical transport properties of pervoskite oxide La$sub{0.9}Tesub{0.1}MnOsub{3}$. This is a novel material with the space group R-3c, which shows the spin-glass-like feature at low temperature and ... More
Resonant interaction between an ultrashort pulse train and a two-level system: frequency domain analysisJun 17 2013We investigate the problem of two-level atoms driven by an ultrashort pulse train in the frequency domain. At low intensity regime, we obtain a perturbative analytical solution that allows us to discuss the role of the mode number of the frequency comb ... More
Doppler broadening thermometry based on cavity ring-down spectroscopyFeb 05 2015Jul 22 2015A Doppler broadening thermometry (DBT) instrument is built based on cavity ring-down spectroscopy (CRDS) for precise determination of the Boltzmann constant. Compared with conventional direct absorption methods, the high-sensitivity of CRDS allows to ... More
Perfect charge compensation in WTe2 for the extraordinary magnetoresistance: From bulk to monolayerDec 29 2014The electronic structure of WTe2 bulk and layers are investigated by using the first principles calculations. The perfect electron-hole (n-p) charge compensation and high carrier mobilities are found in WTe2 bulk, which may result in the large and non-saturating ... More
Small size boundary effects on two-pion interferometryOct 13 1999Apr 20 2000The Bose-Einstein correlations of two identically charged pions are derived when these particles, the most abundantly produced in relativistic heavy ion collisions, are confined in finite volumes. Boundary effects on single pion spectrum are also studied. ... More
Testing the Resolving Power of 2-D K^+ K^+ InterferometryJan 19 1998Adopting a procedure previously proposed to quantitatively study two-dimensional pion interferometry, an equivalent 2-D chi^2 analysis was performed to test the resolving power of that method when applied to less favorable conditions, i.e., if no significant ... More
Value of Information in Feedback ControlDec 18 2018In this article, we investigate the impact of information on networked control systems, and illustrate how to quantify a fundamental property of stochastic processes that can enrich our understanding about such systems. To that end, we develop a theoretical ... More
An Overview of the New Test Stand for H- Ion Sources at FNALNov 05 2015A new test stand at FNAL is being constructed to carry out experiments to develop and upgrade the present magnetron-type sources of H- ions of up to 80 mA at 35 keV in the context of the Proton Improvement Plan (PIP). The aim of this plan is to provide ... More
The FNAL injector upgradeAug 15 2012The present FNAL H- injector has been operational since the 1970s and consists of two magnetron H- sources and two 750 keV Cockcroft-Walton Accelerators. In the upgrade, both slit-type magnetron sources will be replaced with circular aperture sources, ... More
Bucket Shaking Stops Bunch Oscillations In The TevatronNov 02 2011Bunches in the Tevatron are known to exhibit longitudinal oscillations which persist indefinitely. These oscillations are colloquially called "dancing bunches". Although the dancing bunches do not cause single bunch emittance growth or beam loss at injection, ... More
Bucket shaking stops bunch dancing in TevatronAug 17 2012Bunches in Tevatron are known to be longitudinally unstable: their collective oscillations, also called "dancing bunches," persist without any signs of decay. Typically, a damper is used to stop these oscillations, but recently, it was theoretically predicted ... More
A data acquisition system for longitudinal beam properties in a rapid cycling synchrotronAug 17 2012A longitudinal beam properties, data acquisition system has been commissioned to operate in the Fermilab booster ring. This system captures real time information including beam synchronous phase, bunch length, and coupled bunch instability amplitudes ... More
Generalized thermalization in quenched free Fermionic modelsAug 23 2018We investigate generalized thermalization in an isolated free Fermionic chain evolving from an out of equilibrium initial state through a sudden quench. We consider the quench where a Fermionic chain is broken into two disjoint chains. We focus on the ... More
Static Magnetization Properties Of AL800 Garnet MaterialSep 20 2017A second harmonic tunable RF cavity is being developed for the Fermilab Booster. This device, which promises reduction of the particle beam loss at the injection, transition, and extraction stages, employs perpendicularly biased garnet material for frequency ... More
A Large-Deviation Analysis of the Maximum-Likelihood Learning of Markov Tree StructuresMay 07 2009Nov 21 2010The problem of maximum-likelihood (ML) estimation of discrete tree-structured distributions is considered. Chow and Liu established that ML-estimation reduces to the construction of a maximum-weight spanning tree using the empirical mutual information ... More
Learning Latent Tree Graphical ModelsSep 14 2010We study the problem of learning a latent tree graphical model where samples are available only from a subset of variables. We propose two consistent and computationally efficient algorithms for learning minimal latent trees, that is, trees without any ... More
Improvements on the Stability and Operation of a Magnetron H- Ion SourceJan 06 2017The magnetron H- ion sources developed in the 1970s currently in operation at Fermilab provide beam to the rest of the accelerator complex. A series of modifications to these sources have been tested in a dedicated offline test stand with the aim of improving ... More
Continuously Guided Atomic Interferometry Using a Single-Zone Optical Excitation: Theoretical AnalysisSep 19 2003In an atomic interferometer, the phase shift due to rotation is proportional to the area enclosed by the split components of the atom. However, this model is unclear for an atomic interferometer demonstrated recently by Shahriar et al., for which the ... More
Pseudo spin-orbit coupling of Dirac particles in graphene spintronicsJun 10 2008We study the pseudo spin-orbital (SO) effects experienced by massive Dirac particles in graphene, which can potentially be of a larger magnitude compared to the conventional Rashba SO effects experienced by particles in a 2DEG semiconductor heterostructure. ... More
Axial Seamount: Periodic tidal loading reveals stress dependence of the earthquake size distribution (b value)Oct 10 2018Jan 21 2019Earthquake size-frequency distributions commonly follow a power law, with the b value often used to quantify the relative proportion of small and large events. Laboratory experiments have found that the b value of microfractures decreases with increasing ... More
On the Maximum Size of Block Codes Subject to a Distance CriterionJun 15 2017May 02 2018We establish a general formula for the maximum size of finite length block codes with minimum pairwise distance no less than $d$. The achievability argument involves an iterative construction of a set of radius-$d$ balls, each centered at a codeword. ... More
Spectral and spatial observations of microwave spikes and zebra structure in the short radio burst of May 29, 2003Nov 23 2011Nov 28 2011The unusual radio burst of May 29, 2003 connected with the M1.5 flare in AR 10368 has been analyzed. It was observed by the Solar Broadband Radio Spectrometer (SBRS/Huairou station, Beijing) in the 5.2-7.6 GHz range. It proved to be only the third case ... More
High-dimensional structure estimation in Ising models: Local separation criterionJul 08 2011Aug 20 2012We consider the problem of high-dimensional Ising (graphical) model selection. We propose a simple algorithm for structure estimation based on the thresholding of the empirical conditional variation distances. We introduce a novel criterion for tractable ... More
Demonstration Of A Continuously Guided Atomic Interferometer Using A Single-Zone Optical ExcitationNov 24 2003We demonstrate an atomic interferometer in which the atom passes through a single-zone optical beam, consisting of a pair of bichromatic counter-propagating fields. During the passage, the atomic wave packets in two distinct internal states trace out ... More
Implementation of Design Changes Towards a More Reliable, Hands-off Magnetron Ion SourceMay 04 2018As the main $H^{-}$ ion source for the accelerator complex, magnetron ion sources have been used at Fermilab since the 1970s. At the offline test stand, new R&D is carried out to develop and upgrade the present magnetron-type sources of $H^{-}$ ions of ... More
Peiffer product and Peiffer commutator for internal pre-crossed modulesMar 17 2015In this work we introduce the notions of Peiffer product and Peiffer commutator of internal pre-crossed modules over a fixed object B, extending the corresponding classical notions to any semi-abelian category C. We prove that, under mild additional assumptions ... More
Squeezed K^+ K^- correlations in high energy heavy ion collisionsJun 30 2010Jan 03 2011The hot and dense medium formed in high energy heavy ion collisions may modify some hadronic properties. In particular, if hadron masses are shifted in-medium, it was demonstrated that this could lead to back-to-back squeezed correlations (BBC) of particle-antiparticle ... More
Searching for squeezed particle-antiparticle correlations in high energy heavy ion collisionsDec 31 2009Apr 01 2013Squeezed correlations of particle-antiparticle pairs were predicted to exist if the hadron masses were modified in the hot and dense medium formed in high energy heavy ion collisions. Although well-established theoretically, they have not yet been observed ... More
Q-boson interferometry and generalized Wigner functionNov 20 2002Oct 24 2003Bose-Einstein correlations of two identically charged $Q$-bosons are derived considering these particles to be confined in finite volumes. Boundary effects on single $Q$-boson spectrum are also studied. We illustrate the effects on the spectrum and on ... More
On scalar propagators of three-dimensional higher-spin black holesJul 31 2016Aug 06 2016We explore some aspects of three-dimensional higher-spin holography by studying scalar fluctuations in the background of higher-spin black holes. We furnish an independent derivation of the bulk-boundary propagator by purely invoking a well-known infinite ... More
On scalar propagators of three-dimensional higher-spin black holesJul 31 2016Nov 20 2016We explore some aspects of three-dimensional higher-spin holography by studying scalar fluctuations in the background of higher-spin black holes. We furnish an independent derivation of the bulk-boundary propagator by purely invoking a well-known infinite ... More
Closed String Partition Functions in Toroidal Compactifications of Doubled GeometriesMar 19 2014Apr 07 2014We revisit partition functions of closed strings on toroidal backgrounds, including their $\mathbb{Z}_N$ shift orbifolds in the formalism where the dimension of the target space is doubled to make T-duality manifest. In such a T-duality covariant formalism, ... More
Stochastic variational inference for large-scale discrete choice models using adaptive batch sizesMay 22 2014Oct 08 2015Discrete choice models describe the choices made by decision makers among alternatives and play an important role in transportation planning, marketing research and other applications. The mixed multinomial logit (MMNL) model is a popular discrete choice ... More
Use of model reparametrization to improve variational BayesMay 18 2018Jan 11 2019We propose using model reparametrization to improve variational Bayes inference for a class of models whose variables can be classified as global (common across observations) or local (observation specific). Posterior dependency between local and global ... More
Explicit inverse of tridiagonal matrix with applications in autoregressive modelingMar 04 2018Dec 15 2018We present the explicit inverse of a class of symmetric tridiagonal matrices which is almost Toeplitz, except that the first and last diagonal elements are different from the rest. This class of tridiagonal matrices are of special interest in complex ... More
Exploring Three-dimensional Higher-Spin Supergravity based on sl(N |N - 1) Chern-Simons theoriesAug 10 2012Nov 14 2012We investigate various aspects of higher-spin anti-de Sitter supergravity in three dimensions as described by Chern-Simons theory based on the finite-dimensional superalgebra sl(N |N - 1), with the particular case of N = 3 as our prime example. This class ... More
A Proof for a Theorem of Wald in Arbitrary DimensionsDec 19 2009Static, axisymmetric solutions form a large class of important black holes in classical GR. In four dimensions, the existence of their most general metric ansatz relies on the fact that two-dimensional subspaces of the tangent space at each point spanned ... More
Noncommutative spacetime geometry and one-loop effects in primordial cosmologyJul 11 2018We study the effect of noncommutative spacetime geometry on one-loop corrections to the primordial curvature two-point function, arising from various forms of massless spectator matter fields interacting gravitationally with the inflaton. After deforming ... More
One-loop corrections to the primordial tensor spectrum from massless iso-curvature fieldsJul 17 2019We study one-loop corrections to the two-point correlation function of tensor perturbations in primordial cosmology induced by massless spectator matter fields. Using the Schwinger-Keldysh formalism in cosmological perturbation theory, we employ dimensional ... More
A coherent-state-based path integral for quantum mechanics on the Moyal planeNov 23 2006Inspired by a recent work that proposes using coherent states to evaluate the Feynman kernel in noncommutative space, we provide an independent formulation of the path-integral approach for quantum mechanics on the Moyal plane, with the transition amplitude ... More
High power radially polarized light generated from photonic crystal segmented half-wave-plateOct 26 2007We have generated more than 100 watts of radial polarized beam from a Yb fiber laser using a photonics crystal segmented half-wave-plate. We demonstrated the high power handling capability of such a photonics crystal segmented half-wave-plate and show ... More
OFF-ApexNet on Micro-expression Recognition SystemMay 10 2018When a person attempts to conceal an emotion, the genuine emotion is manifest as a micro-expression. Exploration of automatic facial micro-expression recognition systems is relatively new in the computer vision domain. This is due to the difficulty in ... More
Nanoscale broadband transmission lines for spin qubit controlAug 12 2012Jan 23 2013The intense interest in spin-based quantum information processing has caused an increasing overlap between two traditionally distinct disciplines, such as magnetic resonance and nanotechnology. In this work we discuss rigourous design guidelines to integrate ... More
Suppression of superconductivity in layered Bi4O4S3 by Ag dopingAug 27 2012We report X-ray diffraction, magnetization and transport measurements for polycrystalline samples of the new layered superconductor Bi4-xAgxO4S3 (0<x<0.2). The superconducting transition temperature (TC) decreases gradually and finally suppressed for ... More
Superconducting and thermoelectric properties of new layered Superconductor Bi4O4S3Jul 23 2012Polycrystalline sample of the new layered superconductor Bi4O4S3 is successfully synthesized by solid-state reaction method by using Bi, S and Bi2O3 powders with one step reaction. The superconducting transition temperature (Tconset=4.5 K), the zero resistance ... More
Topological Entanglement Entropy and Braids in Chern-Simons TheoryJul 20 2017Oct 04 2017We explore a web of connections between quantum entanglement and knot theory by examining how topological entanglement entropy probes the braiding data of quasi-particles in Chern-Simons theory, mainly using $SU(2)$ gauge group as our working example. ... More
T-duality Twists and Asymmetric OrbifoldsAug 19 2015Sep 16 2015We study some aspects of asymmetric orbifolds of tori, with the orbifold group being some $\mathbb{Z}_N$ subgroup of the T-duality group and, in particular, provide a concrete understanding of certain phase factors that may accompany the T-duality operation ... More
Aspects of Three-dimensional Spin-4 GravityNov 11 2011Aug 23 2012We discuss some interesting holographical aspects of three-dimensional higher-spin gravity with a negative cosmological constant in the framework of SL(4, R) \times SL(4, R) Chern-Simons theory. Using a recently found technique, we construct explicitly ... More
First order Born-Infeld Hydrodynamics via Gauge/Gravity DualityMar 19 2009May 01 2009By performing a derivative expansion on a class of boosted Born-Infeld-AdS_5 black branes, we study the hydrodynamics of the dual field theory - in the spirit of AdS/CFT correspondence. We determine the fluid dynamical stress-energy tensor to first order, ... More
Efficient data augmentation techniques for Gaussian state space modelsDec 24 2017We propose a data augmentation scheme for improving the rate of convergence of the EM algorithm in estimating Gaussian state space models. The scheme is based on a linear transformation of the latent states, and two working parameters are introduced for ... More
One-loop corrections to the primordial tensor spectrum from massless isocurvature fieldsJul 17 2019Aug 01 2019We study one-loop corrections to the two-point correlation function of tensor perturbations in primordial cosmology induced by massless spectator matter fields. Using the Schwinger-Keldysh formalism in cosmological perturbation theory, we employ dimensional ... More
Arbitrary tunable spaser based on double-Fano resonance of two sets of disk-ring nanostructureDec 03 2015This paper demonstrates an arbitrary tunable spaser based on double-Fano resonance of a plasmonic nanostructure consisting of two sets of disk-ring (TSDR) nanostructure. TSDR nanostructure supports two Fano resonances, which can be served as the lasing ... More
Measurement of Scattering Rate and Minimum Conductivity in GrapheneJul 12 2007The conductivity of graphene samples with various levels of disorder is investigated for a set of specimens with mobility in the range of $1-20\times10^3$ cm$^2$/V sec. Comparing the experimental data with the theoretical transport calculations based ... More
Anomalous microwave response of high-temperature superconducting thin-film microstrip resonator in weak dc magnetic fieldsAug 29 1999We have studied an anomalous microwave (mw) response of superconducting YBa_{2}Cu_{3}O_{7-delta} (YBCO) microstrip resonators in the presence of a weak dc magnetic field, H_{dc}. The surface resistance (R_{s}) and reactance (X_{s}) show a correlated non-monotonic ... More
Single-electron shuttle based on a silicon quantum dotMar 30 2011Oct 05 2011We report on single-electron shuttling experiments with a silicon metal-oxide-semiconductor quantum dot at 300 mK. Our system consists of an accumulated electron layer at the Si/SiO_2 interface below an aluminum top gate with two additional barrier gates ... More
Accessible Melanoma Detection using Smartphones and Mobile Image AnalysisNov 27 2017Feb 26 2018We investigate the design of an entire mobile imaging system for early detection of melanoma. Different from previous work, we focus on smartphone-captured visible light images. Our design addresses two major challenges. First, images acquired using a ... More
Chained Bell Inequality Experiment with High-Efficiency MeasurementsDec 06 2016We report correlation measurements on two $^9$Be$^+$ ions that violate a chained Bell inequality obeyed by any local-realistic theory. The correlations can be modeled as derived from a mixture of a local-realistic probabilistic distribution and a distribution ... More
Update on the status of Hadronic Squeezed Correlations at RHIC EnergiesDec 30 2010Mar 10 2013In high energy heavy ion collisions a hot and dense medium is formed, where the hadronic masses may be shifted from their asymptotic values. If this mass modification occurs, squeezed back-to-back correlations (BBC) of particle-antiparticle pairs are ... More
Squeezed correlations among particle-antiparticle pairsDec 09 2008Feb 04 2009The hadronic correlation among particle-antiparticle pairs was highlighted in the late 1990's, culminating with the demonstration that it should exist if the masses of the hadrons were modified in the hot and dense medium formed in high energy heavy ion ... More
New Damped Lya Metallicities from ESI Spectroscopy of Five Palomar Sky Survey QuasarsMay 16 2003This paper presents chemical abundance measurements for 12 new z>3 damped Lya systems discovered toward five quasars from the Palomar Sky Survey. We determine HI column densities from profile fits to the observed damped Lya profiles and measure ionic ... More
Upper limits on the solar-neutron flux at the Yangbajing neutron monitor from BATSE-detected solar flaresMar 16 2007The purpose of this work is to search the Yangbajing neutron monitor data obtained between 1998 October and 2000 June for solar neutrons associated with solar flares. Using the onset times of 166 BATSE-detected flares with the GOES peak flux (1 -- 8 \AA) ... More
Molecular Gas in Infrared Ultraluminous QSO HostsFeb 29 2012We report CO detections in 17 out of 19 infrared ultraluminous QSO (IR QSO) hosts observed with the IRAM 30m telescope. The cold molecular gas reservoir in these objects is in a range of 0.2--2.1$\times 10^{10}M_\odot$ (adopting a CO-to-${\rm H_2}$ conversion ... More
Online Nonnegative Matrix Factorization with OutliersApr 10 2016We propose a unified and systematic framework for performing online nonnegative matrix factorization in the presence of outliers that is particularly suited to large datasets. Within this framework, we propose two solvers based on proximal gradient descent ... More
The Third-Order Term in the Normal Approximation for the AWGN ChannelNov 11 2013Nov 19 2013This paper shows that, under the average error probability formalism, the third-order term in the normal approximation for the additive white Gaussian noise channel with a maximal or equal power constraint is at least $\frac{1}{2} \log n + O(1)$. This ... More
Second-Order Coding Rates for Channels with StateMay 29 2013May 14 2014We study the performance limits of state-dependent discrete memoryless channels with a discrete state available at both the encoder and the decoder. We establish the epsilon-capacity as well as necessary and sufficient conditions for the strong converse ... More
Estimating Signals with Finite Rate of Innovation from Noisy Samples: A Stochastic AlgorithmJan 01 2008Jan 03 2008As an example of the recently-introduced concept of rate of innovation, signals that are linear combinations of a finite number of Diracs per unit time can be acquired by linear filtering followed by uniform sampling. However, in reality, samples are ... More
Second-Order Asymptotics for the Gaussian MAC with Degraded Message SetsOct 04 2013Oct 06 2015This paper studies the second-order asymptotics of the Gaussian multiple-access channel with degraded message sets. For a fixed average error probability $\varepsilon \in (0,1)$ and an arbitrary point on the boundary of the capacity region, we characterize ... More
Equivocations, Exponents and Second-Order Coding Rates under Various Rényi Information MeasuresApr 10 2015Jul 05 2016We evaluate the asymptotics of equivocations, their exponents as well as their second-order coding rates under various R\'{e}nyi information measures. Specifically, we consider the effect of applying a hash function on a source and we quantify the level ... More
Bounds on the Average Distance and Distance Enumerator with Applications to Non-Interactive SimulationApr 08 2019We leverage proof techniques in coding theory and Fourier analysis to derive new bounds for the problem of non-interactive simulation of random variables. Previous bounds in the literature were derived by applying data processing inequalities concerning ... More
Moderate Deviation Asymptotics for Variable-Length Codes with FeedbackJul 16 2017May 16 2018We consider data transmission across discrete memoryless channels (DMCs) using variable-length codes with feedback. We consider the family of such codes whose rates are $\rho_N$ below the channel capacity $C$, where $\rho_N$ is a positive sequence that ... More
Simulation of Random Variables under Rényi Divergence Measures of All OrdersMay 31 2018Dec 21 2018The random variable simulation problem consists in using a $k$-dimensional i.i.d. random vector $X^{k}$ with distribution $P_{X}^{k}$ to simulate an $n$-dimensional i.i.d. random vector $Y^{n}$ so that its distribution is approximately $Q_{Y}^{n}$. In ... More
Time-Division is Optimal for Covert Communication over Some Broadcast ChannelsOct 26 2017Oct 10 2018We consider a covert communication scenario where a transmitter wishes to communicate simultaneously to two legitimate receivers while ensuring that the communication is not detected by an adversary, the warden. The legitimate receivers and the adversary ... More
A Numerical Study on the Wiretap Network with a Simple Network TopologyMay 12 2015Jan 15 2016In this paper, we study a security problem on a simple wiretap network, consisting of a source node S, a destination node D, and an intermediate node R. The intermediate node connects the source and the destination nodes via a set of noiseless parallel ... More
Coexistence of superconductivity and magnetism in K0.8Fe2Se1.4S0.4Jan 27 2011High-quality single crystals of K0.8Fe2Se1.4S0.4 are successfully synthesized by self-flux method with the superconducting transition temperatures Tconset = 32.8 K and Tczero = 31.2 K. In contrast to external pressure effect on superconductivity, the ... More