Results for "Keunwoo Choi"

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Text-based LSTM networks for Automatic Music CompositionApr 18 2016In this paper, we introduce new methods and discuss results of text-based LSTM (Long Short-Term Memory) networks for automatic music composition. The proposed network is designed to learn relationships within text documents that represent chord progressions ... More
Convolutional Recurrent Neural Networks for Music ClassificationSep 14 2016We introduce a convolutional recurrent neural network (CRNN) for music tagging. CRNNs take advantage of convolutional neural networks (CNNs) for local feature extraction and recurrent neural networks for temporal summarisation of the extracted features. ... More
Understanding Music PlaylistsNov 22 2015As music streaming services dominate the music industry, the playlist is becoming an increasingly crucial element of music consumption. Con- sequently, the music recommendation problem is often casted as a playlist generation prob- lem. Better understanding ... More
Towards Music Captioning: Generating Music Playlist DescriptionsAug 17 2016Descriptions are often provided along with recommendations to help users' discovery. Recommending automatically generated music playlists (e.g. personalised playlists) introduces the problem of generating descriptions. In this paper, we propose a method ... More
Explaining Deep Convolutional Neural Networks on Music ClassificationJul 08 2016Deep convolutional neural networks (CNNs) have been actively adopted in the field of music information retrieval, e.g. genre classification, mood detection, and chord recognition. However, the process of learning and prediction is little understood, particularly ... More
Towards Playlist Generation Algorithms Using RNNs Trained on Within-Track TransitionsJun 07 2016We introduce a novel playlist generation algorithm that focuses on the quality of transitions using a recurrent neural network (RNN). The proposed model assumes that optimal transitions between tracks can be modelled and predicted by internal transitions ... More
Automatic tagging using deep convolutional neural networksJun 01 2016We present a content-based automatic music tagging algorithm using fully convolutional neural networks (FCNs). We evaluate different architectures consisting of 2D convolutional layers and subsampling layers only. In the experiments, we measure the AUC-ROC ... More
Revisiting Singing Voice Detection: a Quantitative Review and the Future OutlookJun 04 2018Since the vocal component plays a crucial role in popular music, singing voice detection has been an active research topic in music information retrieval. Although several proposed algorithms have shown high performances, we argue that there still is ... More
Kapre: On-GPU Audio Preprocessing Layers for a Quick Implementation of Deep Neural Network Models with KerasJun 19 2017We introduce Kapre, Keras layers for audio and music signal preprocessing. Music research using deep neural networks requires a heavy and tedious preprocessing stage, for which audio processing parameters are often ignored in parameter optimisation. To ... More
DLR : Toward a deep learned rhythmic representation for music content analysisDec 14 2017In the use of deep neural networks, it is crucial to provide appropriate input representations for the network to learn from. In this paper, we propose an approach to learn a representation that focus on rhythmic representation which is named as DLR (Deep ... More
The Effects of Noisy Labels on Deep Convolutional Neural Networks for Music TaggingJun 07 2017Nov 14 2017Deep neural networks (DNN) have been successfully applied to music classification including music tagging. However, there are several open questions regarding the training, evaluation, and analysis of DNNs. In this article, we investigate specific aspects ... More
A Tutorial on Deep Learning for Music Information RetrievalSep 13 2017May 03 2018Following their success in Computer Vision and other areas, deep learning techniques have recently become widely adopted in Music Information Retrieval (MIR) research. However, the majority of works aim to adopt and assess methods that have been shown ... More
Similarity measures for vocal-based drum sample retrieval using deep convolutional auto-encodersFeb 14 2018The expressive nature of the voice provides a powerful medium for communicating sonic ideas, motivating recent research on methods for query by vocalisation. Meanwhile, deep learning methods have demonstrated state-of-the-art results for matching vocal ... More
A Comparison of Audio Signal Preprocessing Methods for Deep Neural Networks on Music TaggingSep 06 2017Jun 03 2018In this paper, we empirically investigate the effect of audio preprocessing on music tagging with deep neural networks. We perform comprehensive experiments involving audio preprocessing using different time-frequency representations, logarithmic magnitude ... More
Transfer learning for music classification and regression tasksMar 27 2017Sep 13 2017In this paper, we present a transfer learning approach for music classification and regression tasks. We propose to use a pre-trained convnet feature, a concatenated feature vector using the activations of feature maps of multiple layers in a trained ... More
Convolutional Recurrent Neural Networks for Music ClassificationSep 14 2016Nov 03 2016We introduce a convolutional recurrent neural network (CRNN) for music tagging. CRNNs take advantage of convolutional neural networks (CNNs) for local feature extraction and recurrent neural networks for temporal summarisation of the extracted features. ... More
Convolutional Recurrent Neural Networks for Music ClassificationSep 14 2016Dec 21 2016We introduce a convolutional recurrent neural network (CRNN) for music tagging. CRNNs take advantage of convolutional neural networks (CNNs) for local feature extraction and recurrent neural networks for temporal summarisation of the extracted features. ... More
Towards Music Captioning: Generating Music Playlist DescriptionsAug 17 2016Jan 15 2017Descriptions are often provided along with recommendations to help users' discovery. Recommending automatically generated music playlists (e.g. personalised playlists) introduces the problem of generating descriptions. In this paper, we propose a method ... More
Intensive Monitoring Survey of Nearby Galaxies (IMSNG)Jan 31 2019Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a high cadence observation program monitoring nearby galaxies with high probabilities of hosting supernovae (SNe). IMSNG aims to constrain the SN explosion mechanism by inferring sizes of SN progenitor ... More
The definability criterions for convex projective polyhedral reflection groupsJun 11 2012Oct 14 2013Following Vinberg, we find the criterions for a subgroup generated by reflections $\Gamma \subset \SL^{\pm}(n+1,\mathbb{R})$ and its finite-index subgroups to be definable over $\mathbb{A}$ where $\mathbb{A}$ is an integrally closed Noetherian ring in ... More
Dimensionally Constrained Symbolic RegressionJun 20 2011We describe dimensionally constrained symbolic regression which has been developed for mass measurement in certain classes of events in high-energy physics (HEP). With symbolic regression, we can derive equations that are well known in HEP. However, in ... More
The maximal tubes under the deformations of a class of 3-dimensional hyperbolic cone-manifoldsMay 14 2004Recently, Hodgson and Kerckhoff found a small bound on Dehn surgered 3-manifolds from hyperbolic knots not admitting hyperbolic structures using deformations of hyperbolic cone-manifolds. They asked whether the area normalized meridian length squared ... More
The module category weight of compact exceptional Lie groupsJul 14 2013We compute the lower bound estimate for the module category weight of compact exceptional Lie groups by analyzing several Eilenberg--Moore type spectral sequences.
Severi Degrees in Cogenus 4Jan 15 1996Jan 15 1996In this paper, we give closed-form formulae for Severi degrees in cogenus 3 and 4 using Ran's method. These formulae coincide with those of I. Vainsencher and for cogenus 3 case, that of J. Harris and R. Pandharipande. Another result of this paper is ... More
Minor-Embedding in Adiabatic Quantum Computation: I. The Parameter Setting ProblemApr 30 2008We show that the NP-hard quadratic unconstrained binary optimization (QUBO) problem on a graph $G$ can be solved using an adiabatic quantum computer that implements an Ising spin-1/2 Hamiltonian, by reduction through minor-embedding of $G$ in the quantum ... More
Faster Algorithms for Constructing a Concept (Galois) LatticeFeb 19 2006Jun 01 2006In this paper, we present a fast algorithm for constructing a concept (Galois) lattice of a binary relation, including computing all concepts and their lattice order. We also present two efficient variants of the algorithm, one for computing all concepts ... More
Torus actions on cohomology complex generalized Bott manifoldsJan 29 2011Aug 31 2012A torus manifold is a closed smooth manifold of dimension $2n$ having an effective smooth $T^n = (S^1)^n$-action with non-empty fixed points. Petrie \cite{petrie:1973} has shown that any homotopy equivalence between a complex projective space $\CP^n$ ... More
The Lane-Emden system near the critical hyperbola on nonconvex domainsMay 26 2015Jan 05 2016In this paper we study the asymptotic behavior of minimal energy solutions to the Lane-Emden system $-\Delta u = v^p$ and $-\Delta v = u^q$ on bounded domains as the index $(p,q)$ approaches to the critical hyperbola from below. Precisely, we remove the ... More
On commutative, operator amenable subalgebras of finite von Neumann algebrasDec 20 2010Sep 12 2011An open question, raised independently by several authors, asks if a closed amenable subalgebra of ${\mathcal B}({\mathcal H})$ must be similar to an amenable C*-algebra; the question remains open even for singly-generated algebras. In this article we ... More
Singly generated operator algebras satisfying weakened versions of amenabilityFeb 06 2012Aug 03 2012We construct a singly generated subalgebra of ${\mathcal K}({\mathcal H})$ which is non-amenable, yet is boundedly approximately contractible. The example embeds into a homogeneous von Neumann algebra. We also observe that there are singly generated, ... More
Multiply Warped Products with Non-Smooth MetricsApr 25 2002In this article we study manifolds with $C^{0}$-metrics and properties of Lorentzian multiply warped products. We represent the interior Schwarzschild space-time as a multiply warped product space-time with warping functions and we also investigate the ... More
Splitting maps and norm bounds for the cyclic cohomology of biflat Banach algebrasOct 27 2009Apr 25 2010We revisit the old result that biflat Banach algebras have the same cyclic cohomology as $\mathbb C$, and obtain a quantitative variant (which is needed in forthcoming joint work of the author). Our approach does not rely on the Connes-Tsygan exact sequence, ... More
Uniform bounds for point cohomology of $\ell^1({\mathbb Z}_+)$ and related algebrasAug 16 2008May 14 2009It is well-known that the point cohomology of the convolution algebra $\ell^1({\mathbb Z}_+)$ vanishes in degrees 2 and above. We sharpen this result by obtaining splitting maps whose norms are bounded independently of the choice of point module. Our ... More
Simplicial cohomology of augmentation ideals in ${\ell}^1(G)$Nov 23 2007Aug 14 2008Let $G$ be a discrete group. We give a decomposition theorem for the Hochschild cohomology of $\ell^1(G)$ with coefficients in certain $G$-modules. Using this we show that if $G$ is commutative-transitive, the canonical inclusion of bounded cohomology ... More
Small Flavor Conserving CP Violation in Superstring ModelsFeb 21 1994It is well known that supersymmetric models allow new sources for CP violation that arise from soft supersymmetry breaking terms. If unsuppressed, these new CP-violating phases would give too large a neutron electric dipole moment. We discuss a mechanism ... More
A Cross-Layer Approach to Data-aided Sensing using Compressive Random AccessApr 29 2019In this paper, data-aided sensing as a cross-layer approach in Internet-of-Things (IoT) applications is studied, where multiple IoT nodes collect measurements and transmit them to an Access Point (AP). It is assumed that measurements have a sparse representation ... More
Twisted traces of singular moduli of weakly holomorphic modular functionsMay 06 2011Zagier proved that the generating series for the traces of singular moduli is a \textit{weakly holomorphic} modular form of weight 3/2 on $\Gamma_0(4)$. Bruinier and Funke extended the results of Zagier to modular curves of arbitrary genus. Zagier also ... More
The convex real projective orbifolds with radial or totally geodesic ends: a survey of some partial resultsJan 26 2016Oct 26 2017A real projective orbifold has a radial end if a neighborhood of the end is foliated by projective geodesics that develop into geodesics ending at a common point. It has a totally geodesic end if the end can be completed to have the totally geodesic boundary. ... More
A classification of radial and totally geodesic ends of properly convex real projective orbifolds III: the convex but nonproperly convex and non-complete-affine radial endsJul 03 2015Real projective structures on $n$-orbifolds are useful in understanding the space of representations of discrete groups into $\mathrm{SL}(n+1, \mathbb{R})$ or $\mathrm{PGL}(n+1, \mathbb{R})$. A recent work shows that many hyperbolic manifolds deform to ... More
Generalized Faraday law derived from classical forces in a rotating frameApr 02 2009Aug 19 2009We show the additional spin dependent classical force due to the rotation of an electron spin's rest frame is essential to derive a spin-Faraday law by using an analogy with the usual Faraday law. The contribution of the additional spin dependent force ... More
Avoid First Order Quantum Phase Transition by Changing Problem HamiltoniansOct 06 2010Aug 03 2011In Amin and Choi \cite{AC09}, we show that an adiabatic quantum algorithm for the NP-hard maximum independent set (MIS) problem on a set of special family of graphs in which there are exponentially many local maxima would have the exponentially small ... More
Minor-embedding in adiabatic quantum computation: II. Minor-universal graph designJan 18 2010Jan 19 2010In [Choi08], we introduced the notion of minor-embedding in adiabatic quantum optimization. A minor-embedding of a graph G in a quantum hardware graph U is a subgraph of U such that G can be obtained from it by contracting edges. In this paper, we describe ... More
A sharp bound on the convergence rate of an aggregation-based algebraic multi-grid method applied to a 1D model problemOct 28 2012Mar 19 2013We consider the linear system Ax=b arising from one-dimensional Poisson's equation with Dirichlet boundary conditions, where A is the square matrix with the stencil form [-1 2 -1]. Here we show that a pairwise aggregation-based algebraic 2-grid method ... More
Drilling cores of hyperbolic 3-manifolds to prove tamenessOct 18 2004We supply a proof of the fact that a hyperbolic 3-manifold $M$ with finitely generated fundamental group and with no parabolics is topologically tame. This proves the Marden's conjecture. Our approach is to form an exhaustion $M_i$ of $M$ and modify the ... More
Hadron and Quarkmonium ExoticaMar 07 2014A number of charmonium-(bottmonium-)like states have been observed in $B$-factory experiments. Recently the BESIII experiment has joined this search with a unique data sample collected at the different center of mass energies ranging from 3.9 GeV to 4.42 ... More
Toroidal graphs containing neither $K_5^{-}$ nor 6-cycles are 4-choosableJul 11 2013The choosability $\chi_\ell(G)$ of a graph $G$ is the minimum $k$ such that having $k$ colors available at each vertex guarantees a proper coloring. Given a toroidal graph $G$, it is known that $\chi_\ell(G)\leq 7$, and $\chi_\ell(G)=7$ if and only if ... More
L2 and Hp boundedness of strongly singular operators and oscillating operators on Heisenberg groupsMay 06 2012Sep 08 2013In the first part, we obtain sharp results for L^2 boundedness of strongly singular operators on the Heisenberg group. We also define the oscillating convolution operators on the Heisenberg group and study their boundedness properties. In the second part, ... More
On strongly indefinite systems involving the fractional LaplacianFeb 26 2013May 20 2014In this paper we study strongly indefinite systems involving the fractional Laplacian on bounded domains. We obtain existence and non-existence results, $a priori$ estimates of Gidas-Spruck type, and the symmetric property.
Maximum drawdown, recovery and momentumMar 31 2014Mar 31 2015We test predictability on asset price using stock selection rules based on maximum drawdown and consecutive recovery. Monthly momentum- and weekly contrarian-style portfolios ranked by the alternative selection criteria are implemented in various asset ... More
Sphalerons in the Standard Model with a real Higgs singletSep 20 1994Sep 21 1994Sphaleron energies within the standard model with a real Higgs singlet added on are calculated. The coupled non-linear equations of motion are numerically solved and the sphaleron energy evaluated for a set of parameters in the Higgs potential. I find ... More
Canonical decomposition of manifolds with flat real projective structure into (n-1)-convex manifolds and concave affine manifoldsApr 23 1998We try to understand the geometric properties of $n$-manifolds ($n\geq 2$) with geometric structures modeled on $(\bR P^n, \PGL(n+1, \bR))$, i.e., $n$-manifolds with projectively flat torsion free affine connections. We define the notion of $i$-convexity ... More
The decomposition and classification of radiant affine 3-manifoldsDec 19 1997Jul 17 2000An affine manifold is a manifold with torsion-free flat affine connection. A geometric topologist's definition of an affine manifold is a manifold with an atlas of charts to the affine space with affine transition functions; a radiant affine manifold ... More
The universal cover of an affine three-manifold with holonomy of shrinkable dimension $\leq 2$Jun 23 1997Dec 21 1999An affine manifold is a manifold with an affine structure, i.e. a torsion-free flat affine connection. We show that the universal cover of a closed affine 3-manifold $M$ with holonomy group of shrinkable dimension (or discompacit\'e in French) less than ... More
Microstructure of Reflection Holographic Grating Inscribed in an Absorptive Azopolymer FilmSep 08 2015Microstructure of reflection holographic grating fabricated via a photo-isomerization process in an absorptive azopolymer film is analyzed. A surface relief formation takes place on the film surface even in the reflection holographic configuration. The ... More
Persistent Hidden States and Nonlinear Transformation for Long Short-Term MemoryJun 22 2018Dec 07 2018Recurrent neural networks (RNNs) have been drawing much attention with great success in many applications like speech recognition and neural machine translation. Long short-term memory (LSTM) is one of the most popular RNN units in deep learning applications. ... More
The number of orientable small covers over cubesDec 19 2008May 13 2010We count orientable small covers over cubes. We also get estimates for $O_n/R_n$, where $O_n$ is the number of orientable small covers and $R_n$ is the number of all small covers over an $n$-cube up to the Davis-Januszkiewicz equivalence.
Simplicial homology and Hochschild cohomology of Banach semilattice algebrasJun 15 2006The ${\ell}^1$-convolution algebra of a semilattice is known to have trivial cohom ology in degrees 1,2 and 3 whenever the coefficient bimodule is symmetric. We ex tend this result to all cohomology groups of degree $\geq 1$ with symmetric coef ficients. ... More
Observations of B335 in the Millimeter Continuum and the 226 GHz H2CO LineJul 18 2007The protostar B335 was observed in the 1.3 mm continuum and in the H2CO 312 - 211 line with an angular resolution of about 8 arcsec. The mass of the inner envelope detected by the dust continuum emission is about 0.02 Msun. The H2CO spectrum at the protostellar ... More
Newton-Wigner position operator and its corresponding spin operator in relativistic quantum mechanicsDec 01 2014A relativistic spin operator is to be the difference between the total and orbital angular momentum. As the unique position operator for a localized state, the remarkable Newton-Wigner position operator, which has all desirable commutation relations as ... More
Biflatness of ${\ell}^1$-semilattice algebrasJun 15 2006May 10 2007Building on an old result of Duncan and Namioka, we show that the ${\ell}^1$-convolution algebra of a semilattice $S$ is biflat precisely when $S$ is uniformly locally finite. The proof shows in passing that for such $S$ the convolution algebra is isomorphic ... More
A classification of radial and totally geodesic ends of properly convex real projective orbifoldsApr 05 2013Jun 10 2014Real projective structures on $n$-orbifolds are useful in understanding the space of representations of discrete groups into $SL(n+1, \mathbb{R})$ or $PGL(n+1, \mathbb{R})$. A recent work shows that many hyperbolic manifolds deform to manifolds with such ... More
The convex real projective orbifolds with radial or totally geodesic ends: The closedness and openness of deformationsNov 04 2010May 28 2014A real projective orbifold is an $n$-dimensional orbifold modeled on $\mathbb{RP}^n$ with the group $PGL(n+1, \mathbb{R})$. We concentrate on an orbifold that contains a compact codimension $0$ submanifold whose complement is a union of neighborhoods ... More
The number of small covers over cubesFeb 14 2008Mar 04 2008In the present paper we find a bijection between the set of small covers over an $n$-cube and the set of acyclic digraphs with $n$ labeled nodes. Using this, we give a formula of the number of small covers over an $n$-cube (generally, a product of simplices) ... More
Stability and ensemble inequivalence in a globally coupled systemSep 11 2003We consider a system of globally coupled rotors, described by a set of Langevin equations, and examine stability of the incoherent phase. The corresponding Fokker-Planck equation, providing a unified description of microcanonical and canonical ensembles, ... More
Distribution of integral Fourier Coefficients of a Modular Form of Half Integral Weight Modulo PrimesMar 31 2007Recently, Bruinier and Ono classified cusp forms $f(z) := \sum_{n=0}^{\infty} a_f(n)q ^n \in S_{\lambda+1/2}(\Gamma_0(N),\chi)\cap \mathbb{Z}[[q]]$ that does not satisfy a certain distribution property for modulo odd primes $p$. In this paper, using Rankin-Cohen ... More
Distributed Source Coding with One Distortion Criterion and Correlated MessagesAug 15 2009In this paper, distributed (or multiterminal) source coding with one distortion criterion and correlated messages is considered. This problem can be also called ``Berger-Yeung problem with correlated messages''. It corresponds to the source coding part ... More
Construction of a Kinematic Variable Sensitive to the Mass of the Standard Model Higgs Boson in H->WW*->l l nu nu-bar using Symbolic RegressionJun 25 2010We derive a kinematic variable that is sensitive to the mass of the Standard Model Higgs boson (M_H) in the H->WW*->l l nu nu-bar channel using symbolic regression method. Explicit mass reconstruction is not possible in this channel due to the presence ... More
Adiabatic Quantum Algorithms for the NP-Complete Maximum-Weight Independent Set, Exact Cover and 3SAT ProblemsApr 13 2010The problem Hamiltonian of the adiabatic quantum algorithm for the maximum-weight independent set problem (MIS) that is based on the reduction to the Ising problem (as described in [Choi08]) has flexible parameters. We show that by choosing the parameters ... More
A Semidefinite Program for Structured BlockmodelsNov 16 2016Semidefinite programs have recently been developed for the problem of community detection, which may be viewed as a special case of the stochastic blockmodel. Here, we develop a semidefinite program that can be tailored to other instances of the blockmodel, ... More
Near-Online Multi-target Tracking with Aggregated Local Flow DescriptorApr 09 2015In this paper, we focus on the two key aspects of multiple target tracking problem: 1) designing an accurate affinity measure to associate detections and 2) implementing an efficient and accurate (near) online multiple target tracking algorithm. As the ... More
Maximal multiplier on Stratified groupsJun 13 2012Mar 17 2013In this paper, we prove Lp boundedness of maximal multipliers on stratified groups and maximal multipliers on product spaces of those groups.
Oscillating convolution operators on the Heisenberg groupApr 25 2012Jun 13 2012In this paper, we consider oscillating convolution operotors on the Heisenberg group $H^n_a$ with respect to the norm $\rho(x,t) = \rho_1(b x, b t)$ with $\rho_1(x,t)= (|x|^4 + t^2)^{1/4}$. We obtain $L^2$ boundedness properties using the oscillatory ... More
Multiplicity of the Protostar Serpens SMM 1 Revealed by Millimeter ImagingOct 13 2009The Serpens SMM 1 region was observed in the 6.9 mm continuum with an angular resolution of about 0.6 arcsec. Two sources were found to have steep positive spectra suggesting emission from dust. The stronger one, SMM 1a, is the driving source of the bipolar ... More
Directly finite algebras of pseudofunctions on locally compact groupsMay 19 2012Nov 12 2014An algebra $A$ is said to be directly finite if each left invertible element in the (conditional) unitization of $A$ is right invertible. We show that the reduced group ${\rm C}^\ast$-algebra of a unimodular group is directly finite, extending known results ... More
Single-Carrier Index Modulation for IoT UplinkApr 05 2019For the Internet of Things (IoT), there might be a large number of devices to be connected to the Internet through wireless technologies. In general, IoT devices would have various constraints due to limited processing capability, memory, energy source, ... More
On Error Rate Analysis for URLLC over Multiple Fading ChannelsApr 04 2019In this paper, we study ultra-reliable and low-latency communication (URLLC) under fading using multiple frequency or time bins. We investigate an approach to find an upper-bound on the packet error rate when a finite-length code is used. From simulation ... More
A note on some group $C^*$-algebras which are quasi-directly finiteMar 08 2010Jun 06 2010An algebra is said to be quasi-directly finite when any left-invertible element in its unitization is automatically right-invertible. It is an old observation of Kaplansky that the von Neumann algebra of a discrete group has this property; in this note, ... More
Layered Non-Orthogonal Random Access with SIC and Transmit Diversity for Reliable TransmissionsDec 08 2017In this paper, we study a layered random access scheme based on non-orthogonal multiple access (NOMA) to improve the throughput of multichannel ALOHA. At a receiver, successive interference cancellation (SIC) is carried out across layers to remove the ... More
Injective convolution operators on ${\ell}^{\infty}(Γ)$ are surjectiveJun 15 2006Aug 01 2007Let $\Gamma$ be a discrete group and let $f \in \ell^1(\Gamma)$. We observe that if the natural convolution operator $\rho_f:\ell^{\infty}(\Gamma)\to \ell^{\inf ty}(\Gamma)$ is injective, then f is invertible in $\ell^1(\Gamma)$. Our proof simplifies ... More
Group representations with empty residual spectrumJun 16 2009Jan 19 2010Let $X$ be a Banach space on which a discrete group $\Gamma$ acts by isometries. For certain natural choices of $X$, every element of the group algebra, when regarded as an operator on $X$, has empty residual spectrum. We show, for instance, that this ... More
Genus zero BPS invariants for local P^1Jun 23 2011Oct 09 2012We study the equivariant version of the genus zero BPS invariants of the total space of a rank 2 bundle on P^1 whose determinant is O(-2). We define the equivariant genus zero BPS invariants by the residue integrals on the moduli space of stable sheaves ... More
Persistence of Hölder continuity for non-local integro-differential equationsDec 28 2011In this paper, we consider non-local integro-differential equations under certain natural assumptions on the kernel, and obtain persistence of H\"{o}lder continuity for their solutions. In other words, we prove that a solution stays in $C^\beta$ for all ... More
Stability of thermodynamic and dynamical order in a system of globally coupled rotorsJun 01 2005A system of globally coupled rotors is studied in a unified framework of microcanonical and canonical ensembles. We consider the Fokker-Planck equation governing the time evolution of the system, and examine various stationary as well as non-stationary ... More
Different Adiabatic Quantum Optimization Algorithms for the NP-Complete Exact Cover and 3SAT ProblemsOct 06 2010May 31 2011One of the most important questions in studying quantum computation is: whether a quantum computer can solve NP-complete problems more efficiently than a classical computer? In 2000, Farhi, et al. (Science, 292(5516):472--476, 2001) proposed the adiabatic ... More
Spectroscopy results from BelleJan 29 2011We report recent results on the charmonium and charmoniumlike states based on a large data sample recorded at the $\Upsilon(4S)$ and $\Upsilon(5S)$ resonances with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.
A classification of radial or totally geodesic ends of real projective orbifolds I: a survey of resultsJan 02 2015Jan 26 2016Real projective structures on $n$-orbifolds are useful in understanding the space of representations of discrete groups into $\mathrm{SL}(n+1, \mathbb{R})$ or $\mathrm{PGL}(n+1, \mathbb{R})$. A recent work shows that many hyperbolic manifolds deform to ... More
Convex and concave decompositions of affine $3$-manifoldsNov 05 2014Sep 27 2016An (flat) affine $3$-manifold is a $3$-manifold with an atlas of charts to an affine space ${\mathbf R}^3$ with transition maps in the affine transformation group $Aff({\mathbf R}^3)$. We will show that a closed affine $3$-manifold is either an affine ... More
Relativistic hydrodynamic jets in the intracluster mediumMay 12 2017We have performed the first three-dimensional relativistic hydrodynamic simulations of extragalactic jets of pure leptonic and baryonic plasma compositions propagating into a hydrostatic intracluster medium environment. The numerical simulations use a ... More
Efficient Structured Surrogate Loss and Regularization in Structured PredictionSep 14 2018In this dissertation, we focus on several important problems in structured prediction. In structured prediction, the label has a rich intrinsic substructure, and the loss varies with respect to the predicted label and the true label pair. Structured SVM ... More
Maximal multipliers on compact manifolds without boundaryJul 01 2012Mar 20 2014Hormander-Mihklin type multiplier theorem on compacts manifolds withour boundary has been obtained by using the wave kernels. We consider maximal multiplies on this setting. To obtain the result, we carefully deal with the remainder terms and find an ... More
NOMA based Random Access with Multichannel ALOHAJun 27 2017In nonorthogonal multiple access (NOMA), the power difference of multiple signals is exploited for multiple access and successive interference cancellation (SIC) is employed at a receiver to mitigate co-channel interference. Thus, NOMA is usually employed ... More
A Variational Inference based Detection Method for Repetition Coded Generalized Spatial ModulationNov 13 2018In this paper, we consider a simple coding scheme for spatial modulation (SM), where the same set of active transmit antennas is repeatedly used over consecutive multiple transmissions. Based on a Gaussian approximation, an approximate maximum likelihood ... More
NOMA-based Compressive Random Access using Gaussian SpreadingDec 28 2018Compressive random access (CRA) is a random access scheme that has been considered for massive machine-type communication (MTC) with non-orthogonal spreading sequences, where the notion of compressive sensing (CS) is used for low-complexity detectors ... More
Sum of all Black-Scholes-Merton models: An efficient pricing method for spread, basket, and Asian optionsMay 08 2018Contrary to the common view that exact pricing is prohibitive owing to the curse of dimensionality, this study proposes an efficient and unified method for pricing options under multivariate Black-Scholes-Merton (BSM) models, such as the basket, spread, ... More
The warped product approach to magnetically charged GMGHS spacetimeJul 24 2014In the framework of Lorentzian multiply warped products we study the magnetically charged Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS) interior spacetime in the string frame. We also investigate geodesic motion in various hypersurfaces, and compare ... More
NOMA: Principles and Recent ResultsJun 27 2017Although non-orthogonal multiple access (NOMA) is recently considered for cellular systems, its key ideas such as successive interference cancellation (SIC) and superposition coding have been well studied in information theory. In this paper, we overview ... More
Physical approach to price momentum and its application to momentum strategyAug 14 2012Aug 20 2014We introduce various quantitative and mathematical definitions for price momentum of financial instruments. The price momentum is quantified with velocity and mass concepts originated from the momentum in physics. By using the physical momentum of price ... More
A gap theorem for the ZL-amenability constant of a finite groupOct 20 2014May 19 2015It was shown in [A. Azimifard, E. Samei, N. Spronk, JFA 2009; arxiv 0805.3685] that the ZL-amenability constant of a finite group is always at least 1, with equality if and only if the group is abelian. It was also shown in the same paper that for any ... More
Relativistic spin operator and Lorentz transformation of spin state of a massive Dirac particleSep 20 2012Jul 08 2013We have shown the covariant relativistic spin operator is equivalent to the spin operator commuting with the free Dirac Hamiltonian. This implies that the covariant relativistic spin operator is a good quantum observable. The covariant relativistic spin ... More