Results for "Lei Chen"

total 36386took 0.13s
On the non-realizability of braid groups by homeomorphismsAug 24 2018May 20 2019In this paper, we will show that the projection $\text{Homeo}^+(D^2_n)\to B_n$ does not have a section; i.e. the braid group $B_n$ cannot be geometrically realized as a group of homeomorphisms of a disk fixing the boundary point-wise and $n$ marked points ... More
The universal surface bundle over the Torelli space has no sectionsOct 02 2017Oct 09 2017For $g>3$, we give two proofs of the fact that the \emph{Birman exact sequence} for the Torelli group \[ 1\to \pi_1(S_g)\to {\cal I}_{g,1}\to {\cal I}_g\to 1 \] does not split. This result was claimed by G. Mess in \cite{mess1990unit}, but his proof has ... More
Section problems for configuration spaces of surfacesAug 26 2017May 20 2019In this paper we give a close-to-sharp answer to the basic questions: When is there a continuous way to add a point to a configuration of $n$ ordered points on a surface $S$ of finite type so that all the points are still distinct? When this is possible, ... More
Surjective homomorphisms between surface braid groupsApr 17 2017Apr 26 2019Let $PB_n(S_{g,p})$ be the pure braid group of a genus $g>1$ surface with $p$ punctures. In this paper we prove that any surjective homomorphism $PB_n(S_{g,p})\to PB_m(S_{g,p})$ factors through one of the forgetful homomorphisms. We then compute the automorphism ... More
The universal $n$-pointed surface bundle only has $n$ sectionsNov 14 2016Sep 02 2018The classifying space BDiff$(S_{g,n})$ of the orientation-preserving diffeomorphism group of the surface $S_{g,n}$ of genus $g>1$ with $n$ ordered marked points has a universal bundle \[ S_g \to \text{UDiff}(S_{g,n})\xrightarrow{\pi}\text{BDiff}(S_{g,n}). ... More
Section problems for configurations of points on the Riemann sphereJul 26 2018This paper contains a suite of results concerning the problem of adding $m$ distinct new points to a configuration of $n$ distinct points on the Riemann sphere, such that the new points depend continuously on the old. Altogether, the results of the paper ... More
A secure blind watermarking scheme based on DCT domain of the scrambled imageAug 31 2017This paper investigates a secure blind watermarking scheme. The main idea of the scheme not only protects the watermark information but also the embedding positions. To achieve a higher level of security, we propose a sub key generation mechanism based ... More
The Birman exact sequence does not virtually splitApr 30 2018This paper answers a basic question about the Birman exact sequence in the theory of mapping class groups. We prove that the Birman exact sequence does not admit a section over any subgroup $\Gamma$ contained in the Torelli group with finite index. A ... More
A general model for dynamic contact angle over full speed regimeJan 25 2019The prevailing models for advancing dynamic contact angle are under intensive debates, and the fitting performances are far from satisfying in practice. The present study proposes a model based on the recent understanding of the multi-scale structure ... More
Discovering Matching DependenciesMar 19 2009Jun 13 2009The concept of matching dependencies (mds) is recently pro- posed for specifying matching rules for object identification. Similar to the functional dependencies (with conditions), mds can also be applied to various data quality applications such as violation ... More
Network Cross-Validation for Determining the Number of Communities in Network DataNov 06 2014Mar 27 2015The stochastic block model and its variants have been a popular tool in analyzing large network data with community structures. In this paper we develop an efficient network cross-validation (NCV) approach to determine the number of communities, as well ... More
The multiplicity problems for the unitary Ginzburg-Rallis modelsAug 07 2018Aug 26 2018We consider the local multiplicity problems of the analogy of the Ginzburg-Rallis model for the unitary group and the unitary similitude group cases. For the unitary similitude group case, by proving a local trace formula for the model, we are able to ... More
Localized Functional Principal Component AnalysisJan 20 2015We propose localized functional principal component analysis (LFPCA), looking for orthogonal basis functions with localized support regions that explain most of the variability of a random process. The LFPCA is formulated as a convex optimization problem ... More
Non-realizability of the Torelli group as area-preserving homeomorphismsApr 20 2019Nielsen realization problem for the mapping class group $\text{Mod}(S_g)$ asks whether the natural projection $p_g: \text{Homeo}_+(S_g)\to \text{Mod}(S_g)$ has a section. While all the previous results use torsion elements in an essential way, in this ... More
Quantifications of strictly singular operators and strictly cosingular operatorsAug 26 2016We investigate possible quantifications of strictly singular operators, $l_{p}$-strictly singular operators, $c_{0}$-strictly singular operators, strictly cosingular operators, $l_{p}$-strictly cosingular operators. We prove quantitative, even strengthening ... More
Structure theorems for actions of homeomorphism groupsFeb 13 2019Mar 29 2019We give an orbit classification theorem and a general structure theorem for actions of groups of homeomorphisms and diffeomorphisms on manifolds, reminiscent of classical results for actions of (locally) compact groups. . As applications, we give a negative ... More
On the maximum of the permanent of (I-A)Dec 31 2017Let A be an n by n doubly substochastic matrix and denote {\sigma}(A) the sum of all elements of A. In this paper we give the upper bound of the permanent of (I-A) with respect to n and {\sigma}(A).
CrowdFusion: A Crowdsourced Approach on Data Fusion RefinementFeb 02 2017Data fusion has played an important role in data mining because high-quality data is required in a lot of applications. As on-line data may be out-of-date and errors in the data may propagate with copying and referring between sources, it is hard to achieve ... More
Predicting Audience's Laughter Using Convolutional Neural NetworkFeb 08 2017May 09 2017For the purpose of automatically evaluating speakers' humor usage, we build a presentation corpus containing humorous utterances based on TED talks. Compared to previous data resources supporting humor recognition research, ours has several advantages, ... More
On a Question of Bouras concerning weak compactness of almost Dunford-Pettis setsSep 22 2016We give a positive answer to the question of K. Bouras [`Almost Dunford-Pettis sets in Banach lattices', \textit{Rend. Circ. Mat. Palermo (2)} \textbf{ 62} (2013), 227--236] concerning weak compactness of almost Dunford-Pettis sets in Banach lattices. ... More
Universal chosen-ciphertext attack for a family of image encryption schemesMar 28 2019During the past decades, there is a great popularity employing nonlinear dynamics and permutation-substitution architecture for image encryption. There are three primary procedures in such encryption schemes, the key schedule module for producing encryption ... More
Conformal Thermal Tensor Network and Universal Entropy on Topological ManifoldsAug 14 2017Aug 17 2017Partition functions of quantum critical systems, expressed as conformal thermal tensor networks, are defined on various manifolds which can give rise to universal entropy corrections. Through high-precision tensor network simulations of several quantum ... More
DDSL: Efficient Subgraph Listing on Distributed and Dynamic GraphsOct 14 2018Oct 16 2018Subgraph listing is a fundamental problem in graph theory and has wide applications in areas like sociology, chemistry, and social networks. Modern graphs can usually be large-scale as well as highly dynamic, which challenges the efficiency of existing ... More
A single-source molten salt synthesis of uniform octahedral Na2Ti3O7 particels composed of nanorodsMar 08 2018Na2Ti3O7, as one of the most potential anode electrode materials, is expected to play an important role in various fields. In this work, we synthesized uniform hollow octahedral Na2Ti3O7 particles through directly sintering a kind of precursors obtained ... More
Query Workload-based RDF Graph Fragmentation and AllocationAug 31 2015Feb 20 2016As the volume of the RDF data becomes increasingly large, it is essential for us to design a distributed database system to manage it. For distributed RDF data design, it is quite common to partition the RDF data into some parts, called fragments, which ... More
On Efficiently Detecting Overlapping Communities over Distributed Dynamic GraphsJan 18 2018Modern networks are of huge sizes as well as high dynamics, which challenges the efficiency of community detection algorithms. In this paper, we study the problem of overlapping community detection on distributed and dynamic graphs. Given a distributed, ... More
Steady state solution of warped accretion discsMay 25 2009We consider a thin accretion disc warped due to the Bardeen-Petterson effect, presenting both analytical and numerical solutions for the situation that the two viscosity coefficients vary with radius as power law, with the two power law indices not necessarily ... More
Softening Theory of Matter Tuning Atomic Border to Make Soft MaterialsApr 04 2018Regulation of material softness has both theoretical and practical significances due to irreplaceable applications of soft matter in rather diverse areas. This article is dedicated to draft a theoretical category on interpreting the mechanisms lying behind ... More
Black Hole Thermodynamics Based on Unitary EvolutionsApr 07 2015Oct 22 2015In this paper, we try to construct black hole thermodynamics based on the fact that, the formation and evaporation of a black hole can be described by quantum unitary evolutions. First, we show that the Bekenstein-Hawking entropy $S_{BH}$ may not be a ... More
"Almost" Quotient Space, Non-dynamical Decoherence and Quantum MeasurementSep 25 2014Apr 07 2015An alternative approach to decoherence, named non-dynamical decoherence is developed and used to resolve the quantum measurement problem. According to decoherence, the observed system is open to a macroscopic apparatus(together with a possible added environment) ... More
Domain Wall Solitons Arising in Classical Gauge Field TheoriesMay 15 2018Apr 04 2019Domain wall solitons are basic constructs realizing phase transitions in various field-theoretical models and are solutions to some nonlinear ordinary differential equations descending from the corresponding full sets of governing equations in higher ... More
S&CNet: A Enhanced Coarse-to-fine Framework For Monocular Depth CompletionJul 13 2019Real-time depth completing is a critical problem for robotics and autonomous driving tasks. In this paper, we propose a light-weight coarse-to-fine network to complete a dense depth map from a single view RGB image and its related sparse depth map. Both ... More
A Non-monotone Alternating Updating Method for A Class of Matrix Factorization ProblemsMay 18 2017May 15 2018In this paper we consider a general matrix factorization model which covers a large class of existing models with many applications in areas such as machine learning and imaging sciences. To solve this possibly nonconvex, nonsmooth and non-Lipschitz problem, ... More
Hawking Effect as Quantum Inertial EffectOct 22 2015We show that "particle production" by gravitational field, especially the Hawking effect, may be treated as some quantum inertial effect, with the energy of Hawking radiation as some vacuum energy shift. This quantum inertial effect is mainly resulted ... More
The Constrained $L_p$-$L_q$ Basis Pursuit Denoising ProblemJul 01 2019In this paper, we consider the constrained $L_p$-$L_q$ basis pursuit denoising problem, which aims to find a minimizer of $\|\bf{x}\|_p^p$ subject to $\|A\bf{x}-\bf{b}\|_q\leq\sigma$ for given $A \in \mathbb{R}^{m \times n}$, $\bf{b}\in\mathbb{R}^m$, ... More
Agent-based model with asymmetric trading and herding for complex financial systemsJul 20 2014Background: For complex financial systems, the negative and positive return-volatility correlations, i.e., the so-called leverage and anti-leverage effects, are particularly important for the understanding of the price dynamics. However, the microscopic ... More
Finite-key analysis for twin-field quantum key distribution with composable securityMar 21 2019Mar 24 2019Long-distance quantum key distribution (QKD) has long time seriously relied on trusted relay or quantum repeater, which either has security threat or is far from practical implementation. Recently, a solution called twin-field (TF) QKD and its variants ... More
Global Regularity to the Navier-Stokes Equations for A Class of Large Initial DataMar 19 2015Apr 08 2015We prove that for initial data of the form \begin{equation}\nonumber u_0^\epsilon(x) = (v_0^h(x_\epsilon), \epsilon^{-1}v_0^n(x_\epsilon))^T,\quad x_\epsilon = (x_h, \epsilon x_n)^T, n \geq 4, \end{equation} the Cauchy problem of the incompressible Navier-Stokes ... More
Distortion Bounds for Transmitting Correlated Sources with Common Part over MACJul 05 2016Dec 11 2016This paper investigates the joint source-channel coding problem of sending two correlated memoryless sources with common part over a memoryless multiple access channel (MAC). An inner bound and two outer bounds on the achievable distortion region are ... More
High order exceptional points in ultracold Bose gasesNov 13 2018Jan 16 2019We show that arbitrarily high-order exceptional points (EPs) can be achieved in a repulsively interacting two-species Bose gas in one dimension. By exactly solving the non-Hermitian two-boson problem, we demonstrate the existence of third-order EPs when ... More
Coherent-State-Based Twin-Field Quantum Key DistributionJan 15 2019Jun 20 2019Large-scale quantum communication networks are still a huge challenge due to the rate-distance limit of quantum key distribution (QKD). Recently, twin-field (TF) QKD has been proposed to overcome this limit. Here, we prove that coherent-state-based TF-QKD ... More
Nonthermal Spectrum of Hawking RadiationNov 16 2015We show that for the thermal spectrum of Hawking radiation black hole's information loss paradox may still be present, even if including the entanglement information stored in the entangled Minkowski vacuum. And to avoid this inconsistency, the spectrum ... More
Task Assignment on Spatial Crowdsourcing [Experiments and Analyses] (Technical Report)May 31 2016Sep 06 2018Recently, with the rapid development of mobile devices and the crowdsourcing platforms, the spatial crowdsourcing has attracted much attention from the database community. Specifically, spatial crowdsourcing refers to sending a location-based request ... More
Phase glass and zero-temperature phase transition in a randomly frustrated two-dimensional quantum rotor modelJan 09 2008The ground state of the quantum rotor model in two dimensions with random phase frustration is investigated. Extensive Monte Carlo simulations are performed on the corresponding (2+1)-dimensional classical model under the entropic sampling scheme. For ... More
Effects of periodically modulated coupling on amplitude death in nonidentical oscillatorsOct 30 2018Oct 31 2018The effects of periodically modulated coupling on amplitude death in two coupled nonidentical oscillators are explored. The AD domain could be significantly influenced by tuning the modulation amplitude and the modulation frequency of the modulated coupling ... More
The Commutativity Problem of the MapReduce Framework: A Transducer-based ApproachMay 05 2016May 06 2016MapReduce is a popular programming model for data parallel computation. In MapReduce, the reducer produces an output from a list of inputs. Due to the scheduling policy of the platform, the inputs may arrive at the reducers in different order. The commutativity ... More
Agent-based model with multi-level herding for complex financial systemsApr 08 2015In complex financial systems, the sector structure and volatility clustering are respectively important features of the spatial and temporal correlations. However, the microscopic generation mechanism of the sector structure is not yet understood. Especially, ... More
Generalized Common Informations: Measuring Commonness by the Conditional Maximal CorrelationOct 28 2016Jul 24 2017In literature, different common informations were defined by G\'acs and K\"orner, by Wyner, and by Kumar, Li, and Gamal, respectively. In this paper, we define two generalized versions of common informations, named approximate and exact information-correlation ... More
Ultrathin Films of Superconducting Metals as a Platform for Topological SuperconductivityJan 15 2018Jul 24 2018The ingredients normally required to achieve topological superconductivity (TSC) are Cooper pairing, broken inversion symmetry, and broken time-reversal symmetry. We present a theoretical exploration of the possibility of using ultra-thin films of superconducting ... More
Graphdiyne Nanoribbons with Open Hexagonal Rings: Existence of Topological Unprotected Edge StatesAug 29 2017Using first principles calculations, we studied a new class of graphdiyne nanoribbons (GDYNR) with open hexagonal rings on the edges.To avoid the effects from dangling bond, hydrogen or oxygen atoms were absorbed on the edges. There are two kinds of GDYNR ... More
Perturbations of framesDec 12 2013In this paper, we give some sufficient conditions under which perturbations preserve Hilbert frames and near-Riesz bases. Similar results are also extended to frame sequences, Riesz sequences and Schauder frames. It is worth mentioning that some of our ... More
Local manipulation of quantum magnetism in 1D ultracold Fermi gases across narrow resonancesSep 18 2018Sep 19 2018Effective range is a quantity to characterize the energy dependence in two-body scattering strength, and is widely used in cold atomic systems especially across narrow resonances. Here we show that the effective range can significantly modify the magnetic ... More
Strongly interacting one-dimensional quantum gas mixtures with weak p-wave interactionsNov 26 2015Dec 09 2015We study one-dimensional strongly interacting quantum gas mixtures, including both the Bose-Fermi and spin-1/2 Fermi-Fermi mixtures, with weak p-wave interactions between intra-component fermions, and demonstrate that the weak p-wave interaction can not ... More
Quality-Assured Synchronized Task Assignment in CrowdsourcingJun 02 2018With the rapid development of crowdsourcing platforms that aggregate the intelligence of Internet workers, crowdsourcing has been widely utilized to address problems that require human cognitive abilities. Considering great dynamics of worker arrival ... More
Performance Characterization of Multi-threaded Graph Processing Applications on Intel Many-Integrated-Core ArchitectureAug 15 2017Feb 24 2019Intel Xeon Phi many-integrated-core (MIC) architectures usher in a new era of terascale integration. Among emerging killer applications, parallel graph processing has been a critical technique to analyze connected data. In this paper, we empirically evaluate ... More
Finite-key analysis for twin-field quantum key distribution with composable securityMar 21 2019Jun 20 2019Long-distance quantum key distribution (QKD) has long time seriously relied on trusted relay or quantum repeater, which either has security threat or is far from practical implementation. Recently, a solution called twin-field (TF) QKD and its variants ... More
Information Perspective to Probabilistic Modeling: Boltzmann Machines versus Born MachinesDec 12 2017We compare and contrast the statistical physics and quantum physics inspired approaches for unsupervised generative modeling of classical data. The two approaches represent probabilities of observed data using energy-based models and quantum states respectively.Classical ... More
Statistical Mechanics Derived From Quantum MechanicsJan 22 2015Apr 07 2015A pedagogical derivation of statistical mechanics from quantum mechanics is provided, by means of open quantum systems. Besides, a new definition of Boltzmann entropy for a quantum closed system is also given to count microstates in a way consistent with ... More
A Unitary Model of The Black Hole EvaporationJun 26 2014Dec 16 2014A unitary effective field model of the black hole evaporation is proposed to satisfy almost the four postulates of the black hole complementarity (BHC). In this model, we enlarge a black hole-scalar field system by adding an extra radiation detector that ... More
The Commutativity Problem of the MapReduce Framework: A Transducer-based ApproachMay 05 2016Sep 30 2016MapReduce is a popular programming model for data parallel computation. In MapReduce, the reducer produces an output from a list of inputs. Due to the scheduling policy of the platform, the inputs may arrive at the reducers in different order. The commutativity ... More
Efficient Data Gathering in Wireless Sensor Networks Based on Matrix Completion and Compressive SensingFeb 09 2013Gathering data in an energy efficient manner in wireless sensor networks is an important design challenge. In wireless sensor networks, the readings of sensors always exhibit intra-temporal and inter-spatial correlations. Therefore, in this letter, we ... More
Chirality control by electric field in periodically poled MgO-doped lithium niobateApr 05 2012Apr 18 2012We study the chirality of periodically poled MgO-doped lithium niobate (MgO:PPLN) by electro-optic (EO) effect. It shows that optical propagation is reciprocal in MgO:PPLN when quasi-phase-matching (QPM) condition is satisfied, which is similar to natural ... More
Vertical absorption edge and universal onset conductance in semi-hydrogenated grapheneNov 11 2009We show that for graphene with any finite difference in the on-site energy between the two sub-lattices ($\Delta$), The optical absorption edge is determined by the $\Delta$. The universal conductance will be broken and the conductance near the band edge ... More
Excited $B_{c}$ States via Continuum QCDMar 31 2019We study the most recently observed excited $B_{c}$ states with the Dyson-Schwinger equation and the Bethe-Salpeter equation approach of continuum QCD. The obtained $M_{B^+_{c}(2S)}=6.813(16)\text{GeV}$, $M_{B^{*+}_{c}(2S)}=6.841(18)\text{GeV}$ and the ... More
Divisibility hierarchy of open quantum systemsMay 29 2018In the theory of open quantum systems, divisibility of the system dynamical maps is related to memory effects in the dynamics. By decomposing the system Hilbert space as a direct sum of several Hilbert spaces, we study the relationship among the corresponding ... More
Extensions of McCoy RingsAug 14 2007A ring $R$ is said to be right McCoy if the equation $f(x)g(x)=0,$ where $f(x)$ and $g(x)$ are nonzero polynomials of $R[x],$ implies that there exists nonzero $s \in R$ such that $f(x)s = 0$. It is proven that no proper (triangular) matrix ring is one-sided ... More
Vertices in all minimum paired-dominating sets of block graphsAug 20 2009Let $G=(V,E)$ be a simple graph without isolated vertices. A set $S\subseteq V$ is a paired-dominating set if every vertex in $V-S$ has at least one neighbor in $S$ and the subgraph induced by $S$ contains a perfect matching. In this paper, we present ... More
Labelling Algorithms for Paired-domination Problems in Block and Interval GraphsFeb 20 2008Let $G=(V,E)$ be a graph without isolated vertices. A set $S\subseteq V$ is a paired-domination set if every vertex in $V-S$ is adjacent to a vertex in $S$ and the subgraph induced by $S$ contains a perfect matching. The paired-domination problem is to ... More
Reprocessed emission from warped accretion discs induced by the Bardeen-Petterson effectOct 21 2009Dec 14 2009The broad Balmer emission-line profiles resulting from the reprocessing of UV/X-ray radiation from a warped accretion disc induced by the Bardeen-Petterson effect are studied. We adopt a thin warped disc geometry and a central ring-like illuminating source ... More
On the Graver basis of block-structured integer programmingMay 09 2018We consider the 4-block $n$-fold integer programming (IP), in which the constraint matrix consists of $n$ copies of small matrices $A$, $B$, $D$ and one copy of $C$ in a specific block structure. We prove that, the $\ell_{\infty}$-norm of the Graver basis ... More
Fast Iteratively Reweighted Least Squares Algorithms for Analysis-Based Sparsity ReconstructionNov 18 2014Apr 28 2015In this paper, we propose a novel algorithm for analysis-based sparsity reconstruction. It can solve the generalized problem by structured sparsity regularization with an orthogonal basis and total variation regularization. The proposed algorithm is based ... More
Tuning Crowdsourced Human ComputationOct 14 2016As the use of crowdsourcing increases, it is important to think about performance optimization. For this purpose, it is possible to think about each worker as a HPU(Human Processing Unit), and to draw inspiration from performance optimization on traditional ... More
Radiality Constraints for Resilient Reconfiguration of Distribution Systems: Formulation and Application to Microgrid FormationJul 10 2019Network reconfiguration is an effective strategy for different purposes of distribution systems (DSs), e.g., resilience enhancement. In particular, DS automation, distributed generation integration and microgrid (MG) technology development, etc., are ... More
RepTFD: Replay Based Transient Fault DetectionJun 11 2012The advances in IC process make future chip multiprocessors (CMPs) more and more vulnerable to transient faults. To detect transient faults, previous core-level schemes provide redundancy for each core separately. As a result, they may leave transient ... More
On the equivalence between graph isomorphism testing and function approximation with GNNsMay 29 2019Graph neural networks (GNNs) have achieved lots of success on graph-structured data. In the light of this, there has been increasing interest in studying their representation power. One line of work focuses on the universal approximation of permutation-invariant ... More
Unusual behavior of sound velocity of a Bose gas in an optical superlattice at quasi-one-dimensionDec 20 2014A Bose gas trapped in a one-dimensional optical superlattice has emerged as a novel superfluid characterized by tunable lattice topologies and tailored band structures. In this work, we focus on the propagation of sound in such a novel system and have ... More
Resilient Disaster Recovery Logistics of Distribution Systems: Co-Optimize Service Restoration with Repair Crew and Mobile Power Source DispatchJun 20 2018Repair crews (RCs) and mobile power sources (MPSs) are critical resources for distribution system (DS) outage management after a natural disaster. However, their logistics is not well investigated. We propose a resilient scheme for disaster recovery logistics ... More
Processing SPARQL Queries Over Distributed RDF GraphsNov 25 2014Mar 21 2016We propose techniques for processing SPARQL queries over a large RDF graph in a distributed environment. We adopt a "partial evaluation and assembly" framework. Answering a SPARQL query Q is equivalent to finding subgraph matches of the query graph Q ... More
Universal Boundary Entropies in Conformal Field Theory: A Quantum Monte Carlo StudyAug 14 2017Sep 21 2017Recently, entropy corrections on nonorientable manifolds such as the Klein bottle are proposed as a universal characterization of critical systems with an emergent conformal field theory (CFT). We show that entropy correction on the Klein bottle can be ... More
Hybrid Codeword Position Index Modulation for Sparse Code Multiple Access SystemDec 26 2018Apr 29 2019In this paper, a novel variation of codeword position index based sparse code multiple access (CPI-SCMA) system, which is termed as hybrid codeword position index modulated sparse code multiple access (HCPI-SCMA), is proposed to further improve the transmission ... More
Interplay of iron and rare-earth magnetic order in rare-earth iron pnictide superconductors under magnetic fieldJan 12 2017The magnetic properties of iron pnictide superconductors with magnetic rare-earth ions under strong magnetic field are investigated based on the cluster self-consistent field method. Starting from an effective Heisenberg model, we present the evolution ... More
On the non-realizability of braid groups by homeomorphismsAug 24 2018In this paper, we will show that the projection $\text{Homeo}^+(D^2_n)\to B_n$ does not have a section; i.e. the braid group $B_n$ cannot be geometrically realized as a group of homeomorphisms of a disk fixing the boundary point-wise and $n$ marked points ... More
Section problems for configuration spaces of surfacesAug 26 2017Jul 30 2018In this paper we give a close-to-sharp answer to the basic questions: When is there a continuous way to add a point to a configuration of $n$ ordered points on a surface $S$ of finite type so that all the points are still distinct? When this is possible, ... More
Extracting temperature and transverse flow by fitting transverse mass spectra and HBT radii togetherAug 14 2016Sep 16 2016Single particle transverse mass spectra and HBT radii of identical pion and identical kaon are analyzed with a blast-wave parametrization under the assumptions local thermal equilibrium and transverse expansion. Under the assumptions, temperature parameter ... More
Prediction-Based Task Assignment in Spatial Crowdsourcing (Technical Report)Dec 27 2015Feb 20 2017Spatial crowdsourcing refers to a system that periodically assigns a number of location-based workers with spatial tasks nearby (e.g., taking photos or videos at some spatial locations). Previous works on the spatial crowdsourcing usually designed task ... More
AutoKGE: Searching Scoring Functions for Knowledge Graph EmbeddingApr 26 2019Jun 03 2019Scoring functions (SFs), which measure the plausibility of links between entities based on a given relation, have become the crux of knowledge graph embedding (KGE). Lots of SFs have been designed by humans in recent years. However, the improvements are ... More
Online Social Media Recommendation over StreamsJan 04 2019As one of the most popular services over online communities, the social recommendation has attracted increasing research efforts recently. Among all the recommendation tasks, an important one is social item recommendation over high speed social media ... More
On the Coded Caching Delivery Design over Wireless NetworksNov 15 2016Coded caching scheme is a promising technique to migrate the network burden in peak hours, which attains more prominent gains than the uncoded caching. The coded caching scheme can be classified into two types, namely, the centralized and the decentralized ... More
Conclusive quantum-state transfer with a single randomly coupled spin chainJun 09 2006We studied the quantum state transfer in randomly coupled spin chains. By using local memories storing the information and dividing the task into transfer portion and decoding portion, conclusive transfer was ingeniously achieved with just one single ... More
Equivalence of restricted Boltzmann machines and tensor network statesJan 17 2017Feb 05 2018The restricted Boltzmann machine (RBM) is one of the fundamental building blocks of deep learning. RBM finds wide applications in dimensional reduction, feature extraction, and recommender systems via modeling the probability distributions of a variety ... More
Security of quantum key distribution with multiphoton componentsJul 08 2016Most qubit-based quantum key distribution (QKD) protocols extract the secure key merely from single-photon component of the attenuated lasers. However, with the Scarani-Acin-Ribordy-Gisin 2004 (SARG04) QKD protocol, the unconditionally secure key can ... More
On the Dynamic Centralized Coded Caching DesignJun 20 2019Coded caching scheme provides us an effective framework to realize additional coded multicasting gain by exploiting coding into multiple transmitted signals. The goal of coded caching design is to jointly optimize the placement and delivery scheme so ... More
Dynamics of a producer-parasite ecosystem on the brink of collapseJun 14 2013Ecosystems can undergo sudden shifts to undesirable states, but recent studies with simple single species ecosystems have demonstrated that advance warning can be provided by the slowing down of population dynamics near a tipping point. However, it is ... More
Exploring RNN-Transducer for Chinese Speech RecognitionNov 13 2018Apr 23 2019End-to-end approaches have drawn much attention recently for significantly simplifying the construction of an automatic speech recognition (ASR) system. RNN transducer (RNN-T) is one of the popular end-to-end methods. Previous studies have shown that ... More
Surface Magnetic CatalysisJul 28 2017Sep 30 2017We study fermions in a magnetic field in a finite size cylinder. With the boundary condition for the fermion flux, we show that the energy spectra and the wave-functions are modified by the finite size effect; the boundary makes the degenerate Landau ... More
Coupling of RF Antennas to Large Volume Helicon PlasmaNov 29 2018Large volume helicon plasma sources are of particular interest for large scale semiconductor processing, high power plasma propulsion and recently plasma-material interaction under fusion conditions. This work is devoted to studying the coupling of four ... More
The universal $n$-pointed surface bundle only has $n$ sectionsNov 14 2016The classifying space BDiff$(S_{g,n})$ of the orientation-preserving diffeomorphism group of the surface $S_{g,n}$ of genus $g>1$ with $n$ ordered marked points has a universal bundle \[ S_g \to \text{UDiff}(S_{g,n})\xrightarrow{\pi}\text{BDiff}(S_{g,n}). ... More
The number of fiberings of a surface bundle over a surfaceMar 20 2017For a closed manifold $M$, let Fib$(M)$ be the number of distinct fiberings of $M$ as a fiber bundle with fiber a closed surface. In this paper we give the first computation of Fib$(M)$ where $1<\text{Fib}(M)<\infty$ but $M$ is not a product. In particular, ... More
Comment on ``Nonuniversal Exponents in Interface Growth''Sep 13 1998Recently, Newman and Swift[T. J. Newman and M. R. Swift, Phys. Rev. Lett. {\bf 79}, 2261 (1997)] made an interesting suggestion that the strong-coupling exponents of the Kardar-Parisi-Zhang (KPZ) equation may not be universal, but rather depend on the ... More
Analogy between rotation and density for Dirac fermions in a magnetic fieldDec 30 2015May 23 2016We analyse the energy spectra of Dirac fermions in the presence of rotation and magnetic field. We find that the Landau degeneracy is resolved by rotation. A drastic change in the energy dispersion relation leads to the "rotational magnetic inhibition" ... More