Results for "Ziyu Chen"

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The Trajectory of Voice Onset Time with Vocal AgingOct 15 2018Vocal aging, a universal process of human aging, can largely affect one's language use, possibly including some subtle acoustic features of one's utterances like Voice Onset Time. To figure out the time effects, Queen Elizabeth's Christmas speeches are ... More
Series-Expansion Thermal Tensor Network Approach for Quantum Lattice ModelsSep 05 2016Mar 26 2017In this work we propose a series-expansion thermal tensor network (SETTN) approach for efficient simulations of quantum lattice models. This continuous-time SETTN method is based on the numerically exact Taylor series expansion of equilibrium density ... More
Exponential Thermal Tensor Network Approach for Quantum Lattice ModelsDec 30 2017Oct 05 2018We speed up thermal simulations of quantum many-body systems in both one- (1D) and two-dimensional (2D) models in an exponential way by iteratively projecting the thermal density matrix $\hat\rho=e^{-\beta \hat{H}}$ onto itself. We refer to this scheme ... More
Transductive Zero-Shot Learning with Visual Structure ConstraintJan 06 2019Zero-shot Learning (ZSL) aims to recognize objects of the unseen classes, whose instances may not have been seen during training. It associates seen and unseen classes with the common semantic space and provides the visual features for each data instance. ... More
Two-dimensional second-order topological insulator in graphdiyneApr 22 2019A second-order topological insulator (SOTI) in $d$ spatial dimensions features topologically protected gapless states at its $(d-2)$-dimensional boundary at the intersection of two crystal faces, but is gapped otherwise. As a novel topological state, ... More
Formality conjecture for K3 surfacesMar 11 2018Feb 26 2019We give a proof of the formality conjecture of Kaledin and Lehn: on a complex projective K3 surface, the DG algebra RHom(F,F) is formal for any sheaf F polystable with respect to an ample line bundle. Our main tool is the uniqueness of DG enhancement ... More
Representing stable complexes on projective spacesFeb 22 2012Jan 17 2014We give an explicit proof of a Bogomolov-type inequality for $c_3$ of reflexive sheaves on $\mathbb{P}^3$. Then, using resolutions of rank-two reflexive sheaves on $\mathbb{P}^3$, we prove that some strata of the moduli of rank-two complexes that are ... More
Giant Magnetic Quantum Oscillations and Chiral Anomaly in the Thermal Conductivity of a Weyl SemimetalJan 25 2018Giant quantum oscillations of magneto-thermal conductivity amounting to two orders of magnitude of the estimation based on the Wiedemann-Franz law have been observed in the prototypical Weyl semimetal TaAs. The characteristic oscillation frequency ($F$ ... More
Kosterlitz-Thouless transitions and phase diagrams of the interacting monomer-dimer model on a checkerboard latticeApr 07 2015Using the tensor network approach, we investigate the monomer-dimer models on a checkerboard lattice, in which there are interactions (with strength $\nu$) between the parallel dimers on half of the plaquettes. For the fully packed interacting dimer model, ... More
Topology-driven phase transitions in the classical monomer-dimer-loop modelApr 07 2015Apr 08 2015In this work, we investigate the classical loop models doped with monomers and dimers on a square lattice, whose partition function can be expressed as a tensor network (TN). In the thermodynamic limit, we use the boundary matrix product state technique ... More
PT-ISABB: A Hybrid Tree-based Complete Algorithm to Solve Asymmetric Distributed Constraint Optimization ProblemsFeb 16 2019Mar 04 2019Asymmetric Distributed Constraint Optimization Problems (ADCOPs) have emerged as an important formalism in multi-agent community due to their ability to capture personal preferences. However, the existing search-based complete algorithms for ADCOPs can ... More
PT-ISABB: A Hybrid Tree-based Complete Algorithm to Solve Asymmetric Distributed Constraint Optimization ProblemsFeb 16 2019Asymmetric Distributed Constraint Optimization Problems (ADCOPs) have emerged as an important formalism in multi-agent community due to their ability to capture personal preferences. However, the existing search-based complete algorithms for ADCOPs can ... More
PT-ISABB: A Hybrid Tree-based Complete Algorithm to Solve Asymmetric Distributed Constraint Optimization ProblemsFeb 16 2019Apr 11 2019Asymmetric Distributed Constraint Optimization Problems (ADCOPs) have emerged as an important formalism in multi-agent community due to their ability to capture personal preferences. However, the existing search-based complete algorithms for ADCOPs can ... More
Magnetic Generation due to Mass Difference between Charge CarriersNov 01 2013The possibility of spontaneous magnetization due to the "asymmetry in mass" of charge carriers in a system is investigated. Analysis shows that when the masses of positive and negative charge carriers are identical, no magnetization is predicted. However, ... More
Weak solutions for forward--backward SDEs--a martingale problem approachJan 19 2009In this paper, we propose a new notion of Forward--Backward Martingale Problem (FBMP), and study its relationship with the weak solution to the forward--backward stochastic differential equations (FBSDEs). The FBMP extends the idea of the well-known (forward) ... More
Continuous-Time Thermal Tensor Network Approach for Quantum Lattice ModelsSep 05 2016In this Letter we propose a continuous-time thermal tensor network (TTN) approach for efficient simulations of quantum lattice models. The continuous-time TTN method is based on numerically exact Taylor series expansions of equilibrium density operators ... More
Sequential Joint Spectrum Sensing and Channel Estimation for Dynamic Spectrum AccessJan 22 2014Dynamic spectrum access under channel uncertainties is considered. With the goal of maximizing the secondary user (SU) throughput subject to constraints on the primary user (PU) outage probability we formulate a joint problem of spectrum sensing and channel ... More
iCare: A Mobile Health Monitoring System for the ElderlyNov 13 2010This paper describes a mobile health monitoring system called iCare for the elderly. We use wireless body sensors and smart phones to monitor the wellbeing of the elderly. It can offer remote monitoring for the elderly anytime anywhere and provide tailored ... More
Optimal Distributed P2P Streaming under Node Degree BoundsAug 31 2010Jun 19 2012We study the problem of maximizing the broadcast rate in peer-to-peer (P2P) systems under \emph{node degree bounds}, i.e., the number of neighbors a node can simultaneously connect to is upper-bounded. The problem is critical for supporting high-quality ... More
Planecell: Representing the 3D Space with PlanesMar 30 2017Reconstruction based on the stereo camera has received considerable attention recently, but two particular challenges still remain. The first concerns the need to aggregate similar pixels in an effective approach, and the second is to maintain as much ... More
StaQC: A Systematically Mined Question-Code Dataset from Stack OverflowMar 26 2018Stack Overflow (SO) has been a great source of natural language questions and their code solutions (i.e., question-code pairs), which are critical for many tasks including code retrieval and annotation. In most existing research, question-code pairs were ... More
Nef divisors for moduli spaces of complexes with compact supportFeb 02 2016Oct 28 2016In [BM14b], the first author and Macr\`i constructed a family of nef divisors on any moduli space of Bridgeland-stable objects on a smooth projective variety X. In this article, we extend this construction to the setting of any separated scheme Y of finite ... More
Towards Building the Semantic Map from a Monocular Camera with a Multi-task NetworkJan 17 2019In many robotic applications, especially for the autonomous driving, understanding the semantic information and the geometric structure of surroundings are both essential. Semantic 3D maps, as a carrier of the environmental knowledge, are then intensively ... More
Significance of self magnetic field in long-distance collimation of laser-generated electron beamsOct 09 2014Long-distance collimation of fast electron beams generated by laser-metallic-wire targets has been observed in recent experiments, while the mechanism behind this phenomenon remains unclear. In this work, we investigate in detail the laser-wire interaction ... More
Criticality-Enhanced Magnetocaloric Effect in Quantum Spin Chain Material Copper NitrateJul 14 2016Low-dimensional quantum magnets, due to the existence of abundant exotic quantum phases therein and experimental feasibilities in laboratories, continues intriguing people in condensed matter physics. In this work, a comprehensive study of Cu(NO$_3$)$_2$ ... More
Convolutional Sequence to Sequence Non-intrusive Load MonitoringJun 06 2018A convolutional sequence to sequence non-intrusive load monitoring model is proposed in this paper. Gated linear unit convolutional layers are used to extract information from the sequences of aggregate electricity consumption. Residual blocks are also ... More
Short-term Load Forecasting with Deep Residual NetworksMay 30 2018We present in this paper a model for forecasting short-term power loads based on deep residual networks. The proposed model is able to integrate domain knowledge and researchers' understanding of the task by virtue of different neural network building ... More
Thermal Tensor Renormalization Group Simulations of Square-Lattice Quantum Spin ModelsApr 12 2019In this work, we benchmark the well-controlled and numerically accurate exponential thermal tensor renormalization group (XTRG) in the simulation of interacting spin models in two dimensions. Finite temperature introduces a thermal correlation length, ... More
Weyl-loop half metal in Li$_3$(FeO$_3$)$_2$Nov 13 2018Nodal-line metals and semimetals, as interesting topological states of matter, have been mostly studied in nonmagnetic materials. Here, based on first-principles calculations and symmetry analysis, we predict that fully spin-polarized Weyl loops can be ... More
FHEDN: A based on context modeling Feature Hierarchy Encoder-Decoder Network for face detectionDec 11 2017Because of affected by weather conditions, camera pose and range, etc. Objects are usually small, blur, occluded and diverse pose in the images gathered from outdoor surveillance cameras or access control system. It is challenging and important to detect ... More
From Multiple Nodal Chain to Dirac/Weyl Semimetal and Topological Insulator in Ternary Hexagonal MaterialsDec 05 2017Dirac semimetal (DSM) hosts four-fold degenerate isolated band-crossing points with linear dispersion, around which the quasiparticles resemble the relativistic Dirac Fermions. It can be described by a 4 * 4 massless Dirac Hamiltonian which can be decomposed ... More
Monocular Object Instance Segmentation and Depth Ordering with CNNsMay 12 2015Dec 18 2015In this paper we tackle the problem of instance-level segmentation and depth ordering from a single monocular image. Towards this goal, we take advantage of convolutional neural nets and train them to directly predict instance-level segmentations where ... More
Interaction effect in two-dimensional Dirac fermionsApr 12 2013Jul 23 2013Based on the Dirac equations in the two-dimensional $\pi-$ flux model, we study the interaction effects both in nontrivial gapped and gapless Dirac equations with numerical exact diagonalization method. In the presence of the nearest and next nearest ... More
Pressure-induced phase transitions of multiferroic BiFeO3Aug 29 2013Pressure-induced phase transitions of multiferroic BiFeO3 have been investigated using synchrotron radiation X-ray diffraction with diamond anvil cell technique at room temperature. Present experimental data clearly show that rhombohedral (R3c) phase ... More
Electronic structure of LaFe1-xCoxAsO from first principle calculationsJul 20 2008Aug 06 2008Based on the first-principles calculations, we have investigated the geometry, binding properties, density of states and band structures of the novel superconductor LaFe1-xCoxAsO and its parent compounds with the ZrCuSiAs structure. We demonstrate that ... More
Liquid crystal self-assembly of upconversion nanorods enriched by depletion forces for mesostructured material preparationDec 28 2017Monodisperse rod-like colloidal particles are known for spontaneously forming both nematic and smectic liquid crystal phases, but their self-assembly was typically exploited from the fundamental soft condensed matter physics perspective. Here we demonstrate ... More
Bayesian Optimization in AlphaGoDec 17 2018During the development of AlphaGo, its many hyper-parameters were tuned with Bayesian optimization multiple times. This automatic tuning process resulted in substantial improvements in playing strength. For example, prior to the match with Lee Sedol, ... More
Hybrid Dirac Semimetal in CaAgBi Materials FamilyJun 13 2017Based on their formation mechanisms, Dirac points in three-dimensional systems can be classified as accidental or essential. The former can be further distinguished into type-I and type-II, depending on whether the Dirac cone spectrum is completely tipped ... More
Decomposition of noncommutative U(1) gauge potentialDec 02 2007We investigate the decomposition of noncommutative gauge potential $\hat{A_{i}}$, and find it has inner structure, namely, $\hat{A_{i}}$ can be decomposed in two parts $\hat{b_{i}}$ and $\hat{a_{i}}$, here $\hat{b_{i}}$ satisfies gauge transformations ... More
Formality conjecture for K3 surfacesMar 11 2018Jul 04 2018We give a proof of the formality conjecture of Kaledin and Lehn: on a complex projective K3 surface, the DG algebra RHom(F,F) is formal for any sheaf F polystable with respect to an ample line bundle. Our main tool is the uniqueness of DG enhancement ... More
Temperature-dependent bulk viscosity of nitrogen gas determined from spontaneous Rayleigh-Brillouin scatteringMar 23 2013Values for the bulk viscosity of molecular nitrogen gas (N2) were derived from spontaneous Rayleigh-Brillouin (RB) scattering at ultraviolet wavelengths (366.8 nm) and at a 90 degree scattering angle. Analysis of the scattering profiles yield values showing ... More
Birational Geometry of Singular Moduli Spaces of O'Grady TypeApr 27 2014Nov 19 2016Following Bayer and Macr\`{i}, we study the birational geometry of singular moduli spaces $M$ of sheaves on a K3 surface $X$ which admit symplectic resolutions. More precisely, we use the Bayer-Macr\`{i} map from the space of Bridgeland stability conditions ... More
Addressing the Item Cold-start Problem by Attribute-driven Active LearningMay 23 2018In recommender systems, cold-start issues are situations where no previous events, e.g. ratings, are known for certain users or items. In this paper, we focus on the item cold-start problem. Both content information (e.g. item attributes) and initial ... More
A systematic study of Rayleigh-Brillouin scattering in air, N2 and O2 gasesSep 10 2014Spontaneous Rayleigh-Brillouin scattering experiments in air, N2 and O2 have been performed for a wide range of temperatures and pressures at a wavelength of 403 nm and at a 90 degrees scattering angle. Measurements of the Rayleigh-Brillouin spectral ... More
A Top-down Model for Cash CLOApr 16 2010We propose a top-down model for cash CLO. This model can consistently price cash CLO tranches both within the same deal and across different deals. Meaningful risk measures for cash CLO tranches can also be defined and computed. This method is self-consistent, ... More
Deep Fried ConvnetsDec 22 2014Jul 17 2015The fully connected layers of a deep convolutional neural network typically contain over 90% of the network parameters, and consume the majority of the memory required to store the network parameters. Reducing the number of parameters while preserving ... More
Duality Spectral Sequences for Weierstrass Fibrations and ApplicationsJun 06 2017We study duality spectral sequences for Weierstrass fibrations. Using these spectral sequences, we show that on a K-trivial Weierstrass threefold over a K-numerically trivial surface, any line bundle of nonzero fiber degree is taken by a Fourier-Mukai ... More
Quantum size effect on the dissociation of O2 molecules on ultrathin Pb(111) filmsJan 26 2010Using first-principles calculations, we systematically study the dissociation of O$_2$ molecules on different ultrathin Pb(111) films. Based on our previous work revealing the molecular adsorption precursor states for O$_2$, we further explore that why ... More
Birational Geometry of Singular Moduli Spaces of O'Grady TypeApr 27 2014Jun 16 2014Following Bayer and Macr\`{i}, we study the birational geometry of singular moduli spaces $M$ of sheaves on a K3 surface $X$ which admit symplectic resolutions. More precisely, we use the Bayer-Macr\`{i} map from the space of Bridgeland stability conditions ... More
Preservation of semistability under Fourier-Mukai transformsOct 01 2015For a trivial elliptic fibration $X=C \times S$ with $C$ an elliptic curve and $S$ a projective K3 surface of Picard rank $1$, we study how various notions of stability behave under the Fourier-Mukai autoequivalence $\Phi$ on $D^b(X)$, where $\Phi$ is ... More
An Entropy Search Portfolio for Bayesian OptimizationJun 18 2014Mar 04 2015Bayesian optimization is a sample-efficient method for black-box global optimization. How- ever, the performance of a Bayesian optimization method very much depends on its exploration strategy, i.e. the choice of acquisition function, and it is not clear ... More
A Framework for Automated Pop-song Melody Generation with Piano Accompaniment ArrangementDec 28 2018We contribute a pop-song automation framework for lead melody generation and accompaniment arrangement. The framework reflects the major procedures of human music composition, generating both lead melody and piano accompaniment by a unified strategy. ... More
Parallel Multiscale Autoregressive Density EstimationMar 10 2017PixelCNN achieves state-of-the-art results in density estimation for natural images. Although training is fast, inference is costly, requiring one network evaluation per pixel; O(N) for N pixels. This can be sped up by caching activations, but still involves ... More
Theoretical Analysis of Bayesian Optimisation with Unknown Gaussian Process Hyper-ParametersJun 30 2014Bayesian optimisation has gained great popularity as a tool for optimising the parameters of machine learning algorithms and models. Somewhat ironically, setting up the hyper-parameters of Bayesian optimisation methods is notoriously hard. While reasonable ... More
Optimal Paths in Large Deviations of Symmetric Reflected Brownian Motion in the OctantAug 09 2012Jan 31 2013We study the variational problem that arises from consideration of large deviations for semimartingale reflected Brownian motion (SRBM) in the positive octant. Due to the difficulty of the general problem, we consider the case in which the SRBM has rotationally ... More
Nef divisors for moduli spaces of complexes with compact supportFeb 02 2016In [BM14b], the first author and Macr\`i constructed a family of nef divisors on any moduli space of Bridgeland-stable objects on a smooth projective variety X. In this article, we extend this construction to the setting of any separated scheme Y of finite ... More
Measuring Two-Event Structural Correlations on GraphsAug 01 2012Real-life graphs usually have various kinds of events happening on them, e.g., product purchases in online social networks and intrusion alerts in computer networks. The occurrences of events on the same graph could be correlated, exhibiting either attraction ... More
Self-Avoiding Random Dynamics on Integer Complex SystemsNov 23 2011Nov 25 2011This paper introduces a new specialized algorithm for equilibrium Monte Carlo sampling of binary-valued systems, which allows for large moves in the state space. This is achieved by constructing self-avoiding walks (SAWs) in the state space. As a consequence, ... More
Generative Modeling using the Sliced Wasserstein DistanceMar 29 2018Generative Adversarial Nets (GANs) are very successful at modeling distributions from given samples, even in the high-dimensional case. However, their formulation is also known to be hard to optimize and often not stable. While this is particularly true ... More
CoaCor: Code Annotation for Code Retrieval with Reinforcement LearningMar 13 2019To accelerate software development, much research has been performed to help people understand and reuse the huge amount of available code resources. Two important tasks have been widely studied: code retrieval, which aims to retrieve code snippets relevant ... More
Error Analysis for the Particle Filter: Methods and Theoretical SupportMar 26 2019The particle filter is a popular Bayesian filtering algorithm for use in cases where the state-space model is nonlinear and/or the random terms (initial state or noises) are non-Gaussian distributed. We study the behavior of the error in the particle ... More
Creativity: Generating Diverse Questions using Variational AutoencodersApr 11 2017Generating diverse questions for given images is an important task for computational education, entertainment and AI assistants. Different from many conventional prediction techniques is the need for algorithms to generate a diverse set of plausible questions, ... More
Adaptive Hamiltonian and Riemann Manifold Monte Carlo SamplersFeb 25 2013In this paper we address the widely-experienced difficulty in tuning Hamiltonian-based Monte Carlo samplers. We develop an algorithm that allows for the adaptation of Hamiltonian and Riemann manifold Hamiltonian Monte Carlo samplers using Bayesian optimization ... More
Instance-Level Segmentation for Autonomous Driving with Deep Densely Connected MRFsDec 21 2015Apr 27 2016Our aim is to provide a pixel-wise instance-level labeling of a monocular image in the context of autonomous driving. We build on recent work [Zhang et al., ICCV15] that trained a convolutional neural net to predict instance labeling in local image patches, ... More
Bayesian Optimisation for Machine TranslationDec 22 2014This paper presents novel Bayesian optimisation algorithms for minimum error rate training of statistical machine translation systems. We explore two classes of algorithms for efficiently exploring the translation space, with the first based on N-best ... More
Nearest Prime Simplicial Complex for Object RecognitionJun 06 2011The structure representation of data distribution plays an important role in understanding the underlying mechanism of generating data. In this paper, we propose nearest prime simplicial complex approaches (NSC) by utilizing persistent homology to capture ... More
The AC multi-harmonic magnetic susceptibility measurement setup at the LNF-INFNApr 29 2014The AC magnetic susceptibility is a fundamental method in materials science, which allows to probe the dynamic magnetic response of magnetic materials and superconductors. The LAMPS laboratory at the Laboratori Nazionali di Frascati of the INFN hosts ... More
Constraints on the spacetime metric around seven "bare" AGN using X-ray reflection spectroscopyJan 10 2019We present the study of a sample of seven "bare" active galactic nuclei (AGN) observed with Suzaku. We interpret the spectrum of these sources with a relativistic reflection component and we employ our model RELXILL_NK to test the Kerr nature of their ... More
Rayleigh-Brillouin scattering of carbon dioxideApr 25 2014The spectral lineshape of spontaneous Rayleigh-Brillouin scattering in CO2 is studied in a range of pressures. The spectrum is influenced by the bulk viscosity, which is a relaxation phenomenon involving the internal degrees of freedom of the molecule. ... More
Dynamic Switch-Controller Association and Control Devolution for SDN SystemsFeb 10 2017Sep 06 2017In software-defined networking (SDN), as data plane scale expands, scalability and reliability of the control plane have become major concerns. To mitigate such concerns, two kinds of solutions have been proposed separately. One is multi- controller architecture, ... More
Rayleigh-Brillouin scattering profiles of air at different temperatures and pressuresJul 02 2013Rayleigh Brillouin (RB) scattering profiles for air have been recorded for the temperature range from 255 to 340 K and the pressure range from 640 to 3300 mbar, covering the conditions relevant for the Earth's atmosphere and for planned atmospheric light ... More
Total transmission and total reflection of acoustic wave by zero index metamaterials loaded with general solid defectsJul 19 2013Aug 19 2013This work investigates acoustic wave transmission property through a zero index metamaterials (ZIM) waveguide embedded with a general solid defect. Total transmission and total reflection can be achieved by adjusting the parameters of the solid defect. ... More
Function Space Particle Optimization for Bayesian Neural NetworksFeb 26 2019While Bayesian neural networks (BNNs) have drawn increasing attention, their posterior inference remains challenging, due to the high-dimensional and over-parameterized nature. To address this issue, several highly flexible and scalable variational inference ... More
Interactive Semantic Parsing for If-Then Recipes via Hierarchical Reinforcement LearningAug 21 2018Nov 14 2018Given a text description, most existing semantic parsers synthesize a program in one shot. However, it is quite challenging to produce a correct program solely based on the description, which in reality is often ambiguous or incomplete. In this paper, ... More
Constraints on the spacetime metric around seven "bare" AGNs using X-ray reflection spectroscopyJan 10 2019Apr 02 2019We present the study of a sample of seven "bare" active galactic nuclei (AGN) observed with Suzaku. We interpret the spectrum of these sources with a relativistic reflection component and we employ our model RELXILL_NK to test the Kerr nature of their ... More
Bayesian Multi-Scale Optimistic OptimizationFeb 27 2014Bayesian optimization is a powerful global optimization technique for expensive black-box functions. One of its shortcomings is that it requires auxiliary optimization of an acquisition function at each iteration. This auxiliary optimization can be costly ... More
Bayesian Optimization for Adaptive MCMCOct 29 2011This paper proposes a new randomized strategy for adaptive MCMC using Bayesian optimization. This approach applies to non-differentiable objective functions and trades off exploration and exploitation to reduce the number of potentially costly objective ... More
The geometry of degenerations of Hilbert schemes of pointsFeb 02 2018Feb 16 2018Given a strict simple degeneration $f \colon X\to C$ the first three authors previously constructed a degeneration $I^n_{X/C} \to C$ of the relative degree $n$ Hilbert scheme of $0$-dimensional subschemes. In this paper we investigate the geometry of ... More
Deep Reinforcement Learning for Sponsored Search Real-time BiddingMar 01 2018Bidding optimization is one of the most critical problems in online advertising. Sponsored search (SS) auction, due to the randomness of user query behavior and platform nature, usually adopts keyword-level bidding strategies. In contrast, the display ... More
On the Imbedding Problem for Three-state Time Homogeneous Markov Chains with Coinciding Negative EigenvaluesSep 11 2010For an indecomposable $3\times 3$ stochastic matrix (i.e., 1-step transition probability matrix) with coinciding negative eigenvalues, a new necessary and sufficient condition of the imbedding problem for time homogeneous Markov chains is shown by means ... More
On the anti-canonical geometry of weak $\mathbb{Q}$-Fano threefolds, IIAug 16 2017By a canonical (resp. terminal) weak $\mathbb{Q}$-Fano $3$-fold we mean a normal projective one with at worst canonical (resp. terminal) singularities on which the anti-canonical divisor is $\mathbb{Q}$-Cartier, nef and big. For a canonical weak $\mathbb{Q}$-Fano ... More
On the anti-canonical geometry of $\mathbb{Q}$-Fano 3-foldsAug 27 2014Feb 02 2015For a $\mathbb{Q}$-Fano 3-fold $X$ on which $K_X$ is a canonical divisor, we investigate the geometry induced from the linear system $|-mK_X|$ in this paper and prove that the anti-$m$-canonical map $\varphi_{-m}$ is birational onto its image for all ... More
Minimum K_2,3-saturated GraphsDec 19 2010Nov 11 2012A graph is K_{2,3}-saturated if it has no subgraph isomorphic to K_{2,3}, but does contain a K_{2,3} after the addition of any new edge. We prove that the minimum number of edges in a K_{2,3}-saturated graph on n >= 5 vertices is sat(n, K_{2,3}) = 2n ... More
Orthogonal Quantum Group Invariants of LinksJul 09 2010We study the Chern-Simons partition function of orthogonal quantum group invariants, and propose a new orthogonal Labastida-Mari\~{n}o-Ooguri-Vafa conjecture as well as degree conjecture for free energy associated to the orthogonal Chern-Simons partition ... More
Gravitational instantons with faster than quadratic curvature decay (III)Mar 28 2016Oct 06 2016This is our third paper in a series on the gravitational instantons. In this paper, we classify ALG and ALH gravitational instantons. In ALG case, we extend Hein's construction slightly and show that it's the only ALG gravitational instanton. In ALH case, ... More
Gravitational instantons with faster than quadratic curvature decay (II)Aug 31 2015Jun 23 2016This is our second paper in a series to study gravitational instantons, i.e. complete hyperk\"aler 4-manifolds with faster than quadratic curvature decay. We prove two main theorems: 1.The asymptotic rate of gravitational instantons to the standard models ... More
Angora: Efficient Fuzzing by Principled SearchMar 04 2018Mar 27 2018Fuzzing is a popular technique for finding software bugs. However, the performance of the state-of-the-art fuzzers leaves a lot to be desired. Fuzzers based on symbolic execution produce quality inputs but run slow, while fuzzers based on random mutation ... More
Modeling the Annual Growth Rate of Electricity Consumption of China in the 21st Century: Trends and PredictionOct 21 2017In this paper, the annual growth rate of electricity consumption in China in the first 15 years of the 21st century is modeled using multiple linear regression. Historical data and trends of gross domestic product, fixed assets investment and share of ... More
Characterizations of asymptotic distributions of continuous-time Pólya processesNov 29 2016Sep 02 2018We propose an elementary but effective approach to studying a general class of Poissonized tenable and balanced urns on two colors. We characterize the asymptotic behavior of the process via a partial differential equation that governs the process, coupled ... More
Faster Deterministic Algorithms for Packing, Matching and $t$-Dominating Set ProblemsJun 15 2013In this paper, we devise three deterministic algorithms for solving the $m$-set $k$-packing, $m$-dimensional $k$-matching, and $t$-dominating set problems in time $O^*(5.44^{mk})$, $O^*(5.44^{(m-1)k})$ and $O^*(5.44^{t})$, respectively. Although recently ... More
Exact Sample Size Methods for Estimating Parameters of Discrete DistributionsNov 08 2012Nov 19 2012In this paper, we develop an approach for the exact determination of the minimum sample size for estimating the parameter of an integer-valued random variable, which is parameterized by its expectation. Under some continuity and unimodal property assumptions, ... More
Principal boundary of moduli spaces of abelian and quadratic differentialsNov 05 2016The seminal work of Eskin-Masur-Zorich described the principal boundary of moduli spaces of abelian differentials that parameterizes flat surfaces with a prescribed generic configuration of short parallel saddle connections. In this paper we describe ... More
Gröbner-Shirshov bases for metabelian Lie algebrasJun 13 2011In this paper, we establish the Gr\"{o}bner-Shirshov bases theory for metabelian Lie algebras. As applications, we find the Gr\"{o}bner-Shirshov bases for partial commutative metabelian Lie algebras related to circuits, trees and some cubes.
Gravitational instantons with faster than quadratic curvature decay (I)May 07 2015In this paper, we study gravitational instantons (i.e., complete hyperk\"aler 4-manifolds with faster than quadratic curvature decay). We prove three main theorems: 1.Any gravitational instanton must have known end----ALE, ALF, ALG or ALH. 2.In ALG and ... More
Exact Methods for Multistage Estimation of a Binomial ProportionFeb 13 2013We first review existing sequential methods for estimating a binomial proportion. Afterward, we propose a new family of group sequential sampling schemes for estimating a binomial proportion with prescribed margin of error and confidence level. In particular, ... More
Embedding of tenable and balanced urn scheme into continuous-time Pólya processNov 29 2016We study poissonized tenable and balanced urns on two colors, say white and blue. In particular, we look at the process obtained by embedding a generalized P\'{o}lya-Eggenberger urn into continuous time. We analyze the number of white and blue balls after ... More
Some sufficient conditions for infinite collisions of simple random walks on a wedge combOct 26 2010In this paper, we give some sufficient conditions for the infinite collisions of independent simple random walks on a wedge comb with profile $\{f(n), n\in \ZZ\}$. One interesting result is that if $f(n)$ has a growth order as $n\log n$, then two independent ... More
Mathematical foundation of nonequilibrium fluctuation-dissipation theorems for inhomogeneous diffusion processes with unbounded coefficientsAug 30 2017Sep 24 2017Nonequilibrium fluctuation-dissipation theorems (FDTs) are one of the most important advances in stochastic thermodynamics over the past two decades. Here we provide a rigourous mathematical theory of two types of nonequilibrium FDTs for inhomogeneous ... More
Fine Residual Carrier Frequency and Sampling Frequency Estimation in Wireless OFDM SystemsNov 08 2012This paper presents a novel algorithm for residual phase estimation in wireless OFDM systems, including the carrier frequency offset (CFO) and the sampling frequency offset (SFO). The subcarriers are partitioned into several regions which exhibit pairwise ... More
Dueling Network Architectures for Deep Reinforcement LearningNov 20 2015Apr 05 2016In recent years there have been many successes of using deep representations in reinforcement learning. Still, many of these applications use conventional architectures, such as convolutional networks, LSTMs, or auto-encoders. In this paper, we present ... More