Results for "Hamza Alkhatib"

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Robust Adaptive Median Binary Pattern for noisy texture classification and retrievalMay 15 2018Texture is an important cue for different computer vision tasks and applications. Local Binary Pattern (LBP) is considered one of the best yet efficient texture descriptors. However, LBP has some notable limitations, mostly the sensitivity to noise. In ... More
A New Kalman Filter Model for Nonlinear Systems Based on Ellipsoidal BoundingFeb 08 2018In this paper, a new filter model called set-membership Kalman filter for nonlinear state estimation problems was designed, where both random and unknown but bounded uncertainties were considered simultaneously in the discrete-time system. The main loop ... More
RSA algorithm with a new approach encryption and decryption message text by asciiJan 09 2016In many research works, there has been an orientation to studying and developing many of the applications of public-key cryptography to secure the data while transmitting in the systems, In this paper we present an approach to encrypt and decrypt the ... More
Accelerating Iterative SpMV for Discrete Logarithm Problem Using GPUsSep 25 2012Dec 04 2014In the context of cryptanalysis, computing discrete logarithms in large cyclic groups using index-calculus-based methods, such as the number field sieve or the function field sieve, requires solving large sparse systems of linear equations modulo the ... More
On representing the positive semidefinite cone using the second-order coneOct 16 2016The second-order cone plays an important role in convex optimization and has strong expressive abilities despite its apparent simplicity. Second-order cone formulations can also be solved more efficiently than semidefinite programming in general. We consider ... More
Analysis of Research in Healthcare Data AnalyticsJun 04 2016The main aim of this paper is to provide a deep analysis on the research field of healthcare data analytics. This paper is analyzing the previous studies and works in this research area, as well as highlighting some of guidelines and gaps. This study ... More
Effects of the quenched random crystal field on the non-equilibrium relaxation process of the spin-3/2 Blume-Capel modelOct 08 2011Sep 27 2012In this work, the relaxation process of the spin-3/2 Blume-Capel model with quenched random crystal field on a two dimensional square lattice has been investigated by a method which combines the statistical equilibrium theory and the thermodynamic of ... More
Magnetic response of a disordered binary ferromagnetic alloy to an oscillating magnetic fieldApr 11 2015By means of Monte Carlo simulation with local spin update Metropolis algorithm, we have elucidated non-equilibrium phase transition properties and stationary-state treatment of a disordered binary ferromagnetic alloy of the type $A_{p}B_{1-p}$ on a square ... More
An introduced effective-field theory study of spin-1 transverse Ising model with crystal field anisotropy in a longitudinal magnetic fieldFeb 16 2010A spin-1 transverse Ising model with longitudinal crystal field in a longitudinal magnetic field is examined by introducing an effective field approximation (IEFT) which includes the correlations between different spins that emerge when expanding the ... More
Optimal Test Sets for Context-Free LanguagesNov 21 2016A test set for a formal language (set of strings) L is a subset T of L such that for any two string homomorphisms f and g defined on L, if the restrictions of f and g on T are identical functions, then f and g are identical on the entire L. Previously, ... More
Differentiable mappings on products with different degrees of differentiability in the two factorsAug 31 2012Mar 28 2014We develop differential calculus of $C^{r,s}$-mappings on products of locally convex spaces and prove exponential laws for such mappings. As an application, we consider differential equations in Banach spaces depending on a parameter in a locally convex ... More
Lieb's concavity theorem, matrix geometric means, and semidefinite optimizationDec 10 2015Mar 23 2016A famous result of Lieb establishes that the map $(A,B) \mapsto \text{tr}\left[K^* A^{1-t} K B^t\right]$ is jointly concave in the pair $(A,B)$ of positive definite matrices, where $K$ is a fixed matrix and $t \in [0,1]$. In this paper we show that Lieb's ... More
Monte Carlo investigation of a spherical ferrimagnetic core-shell nanoparticle under a time dependent magnetic fieldFeb 25 2013Feb 26 2013Monte Carlo simulation based on Metropolis algorithm has been used with a great success to analyze the dynamic phase transition properties of a single spherical core-shell nanoparticle system with a spin-3/2 core surrounded by a spin-1 shell layer with ... More
On Rogers-Ramanujan functions, binary quadratic forms and eta-quotientsApr 04 2012Jul 22 2012In a handwritten manuscript published with his lost notebook, Ramanujan stated without proofs forty identities for the Rogers-Ramanujan functions. We observe that the functions that appear in Ramanujan's identities can be obtained from a Hecke action ... More
New Identities for 7-cores with prescribed BG-rankMar 06 2006Sep 15 2007A q-series with nonnegative power series coefficients is called positive. The partition statistics BG-rank is defined as an alternating sum of parities of parts of a partition. It is known that the generating function for the number of partitions of n ... More
The blow-up rate for strongly perturbed semilinear wave equations in the conformal regime without a radial assumptionDec 21 2015We consider in this paper a large class of perturbed semilinear wave equations with critical (in the conformal transform sense) power nonlinearity. We will show that the blow-up rate of any singular solution is given by the solution of the non-perturbed ... More
Decay of Qubits under arbitrary space-time trajectories: The Zeno & Anti-Zeno EffectsNov 23 2018Modeling an arbitrarily accelerating qubit as an open quantum system, we derive an exact solution for the pure-dephasing model ($\sigma_z$ coupling) under arbitrary qubit space-time trajectories, as well as general expressions for the survival probabilities ... More
Correlated Markov Quantum WalksOct 21 2011We consider the discrete time unitary dynamics given by a quantum walk on $\Z^d$ performed by a particle with internal degree of freedom, called coin state, according to the following iterated rule: a unitary update of the coin state takes place, followed ... More
Three-qutrit entanglement and simple singularitiesJun 17 2016In this paper, we use singularity theory to study the entanglement nature of pure three-qutrit systems. We first consider the algebraic variety $X$ of separable three-qutrit states within the projective Hilbert space $\mathbb{P}(\mathcal{H}) = \mathbb{P}^{26}$. ... More
Mode-coupling and nonlinear Landau damping effects in auroral Farley-Buneman turbulenceOct 01 1998The fundamental problem of Farley-Buneman turbulence in the auroral $E$-region has been discussed and debated extensively in the past two decades. In the present paper we intend to clarify the different steps that the auroral $E$-region plasma has to ... More
Cognitive Power Control Under Correlated Fading and Primary-Link CSISep 29 2009We consider the cognitive power control problem of maximizing the secondary throughput under an outage probability constraint on a constant-power constant-rate primary link. We assume a temporally correlated primary channel with two types of feedback: ... More
Spectral Properties of Non-Unitary Band MatricesMar 15 2014Oct 22 2014We consider families of random non-unitary contraction operators defined as deformations of CMV matrices which appear naturally in the study of random quantum walks on trees or lattices. We establish several deterministic and almost sure results about ... More
The hadronization time of heavy quark in nuclear matterJan 18 2016We study the hadronization time of heavy quark in nuclear matter by using the coalescence model and the spatial diffusion constant of heavy quark from lattice Quantum Chromodynamic calculations, assuming that the main interaction of heavy quark at the ... More
Thermalization of Fermionic Quantum WalkersNov 22 2016We consider the discrete time dynamics of an ensemble of fermionic quantum walkers moving on a finite discrete sample, interacting with a reservoir of infinitely many quantum particles on the one dimensional lattice. The reservoir is given by a fermionic ... More
Dynamic phase transitions in a ferromagnetic thin film system: A Monte Carlo simulation studyApr 18 2015Dynamic phase transition properties of ferromagnetic thin film system under the influence both bias and time dependent magnetic fields have been elucidated by means of kinetic Monte Carlo simulation with local spin update Metropolis algorithm. The obtained ... More
Nonequilibrium dynamics of a mixed spin-1/2 and spin-3/2 Ising ferrimagnetic system with a time dependent oscillating magnetic field sourceNov 14 2013Aug 26 2014Nonequilibrium phase transition properties of a mixed Ising ferrimagnetic model consisting of spin-1/2 and spin-3/2 on a square lattice under the existence of a time dependent oscillating magnetic field have been investigated by making use of Monte Carlo ... More
Sedimentation of granular columns in the viscous and weakly inertial regimesOct 31 2013We investigate the dynamics of granular columns of point particles that interact via long-range hydrodynamic interactions and fall under the action of gravity. We investigate the influence of inertia using the Green's function for the Oseen equation. ... More
On inversion and connection coefficients for basic hypergeometric polynomialsDec 12 2015In this paper, we propose a general method to express explicitly the inversion and the connection coefficients between two basic hypergeometric polynomial sets. As application, we consider some $d$-orthogonal basic hypergeometric polynomials and we derive ... More
Ramanujan's Identities and Representation of Integers by Certain Binary and Quaternary Quadratic FormsNov 10 2006Feb 06 2007We revisit old conjectures of Fermat and Euler regarding representation of integers by binary quadratic form x^2+5y^2. Making use of Ramanujan's_1\psi_1 summation formula we establish a new Lambert series identity for \sum_{n,m=-\infty}^{\infty} q^{n^2+5m^2}. ... More
Spectral Graph Theoretic Analysis of Tsallis Entropy-based Dissimilarity MeasureApr 08 2015Apr 14 2015In this paper we introduce a nonextensive quantum information theoretic measure which may be defined between any arbitrary number of density matrices, and we analyze its fundamental properties in the spectral graph-theoretic framework. Unlike other entropic ... More
Resonance broadening theory of Farley-Buneman turbulence in the auroral E-regionOct 01 1998The conventional theory of resonance broadening for a two-species plasma in a magnetic field is revised, and applied to an ionospheric turbulence case. The assumptions made in the conventional theory of resonance broadening have, in the past, led to replacing ... More
Nonequilibrium dynamics of a spin-3/2 Blume Capel model with quenched random crystal fieldSep 26 2012The relaxation and complex magnetic susceptibility treatments of a spin-3/2 Blume-Capel model with quenched random crystal field on a two dimensional square lattice are investigated by a method combining the statistical equilibrium theory and the thermodynamics ... More
Lyapunov Exponents for Unitary Anderson ModelsNov 28 2006We study a unitary version of the one-dimensional Anderson model, given by a five diagonal deterministic unitary operator multiplicatively perturbed by a random phase matrix. We fully characterize positivity and vanishing of the Lyapunov exponent for ... More
On the representations of integers by the sextenary quadratic form x^2+y^2+z^2+ 7s^2+7t^2+ 7u^2 and 7-coresApr 13 2008In this paper we derive an explicit formula for the number of representations of an integer by the sextenary form x^2+y^2+z^2+ 7s^2+7t^2+ 7u^2. We establish the following intriguing inequalities 2b(n)>=a_7(n)>=b(n) for n not equal to 0,2,6,16. Here a_7(n) ... More
Spectral Transition for Random Quantum Walks on TreesDec 25 2012May 09 2013We define and analyze random quantum walks on homogeneous trees of degree $q\geq 3$. Such walks describe the discrete time evolution of a quantum particle with internal degree of freedom in $\C^q$ hopping on the neighboring sites of the tree in presence ... More
On nonexistence of non-constant volatility in the Black-Scholes formulaFeb 10 2005We prove that if the Black-Scholes formula holds with the spot volatility for call options with all strikes, then the volatility parameter is constant. The proof relies some result on semimartingales (Theorem 2) of independent interest.
A Multicomponent Approach to Nonrigid Registration of Diffusion Tensor ImagesApr 08 2015Apr 14 2015We propose a nonrigid registration approach for diffusion tensor images using a multicomponent information-theoretic measure. Explicit orientation optimization is enabled by incorporating tensor reorientation, which is necessary for wrapping diffusion ... More
A Lyapunov functional and blow-up results for a class of perturbed semilinear wave equationsFeb 11 2010We consider in this paper some class of perturbation for the semilinear wave equation with subcritical (in the conformal transform sense) power nonlinearity. We first derive a Lyapunov functional in similarity variables and then use it to derive the blow-up ... More
Exponential lower bounds on fixed-size psd rank and semidefinite extension complexityNov 11 2013There has been a lot of interest recently in proving lower bounds on the size of linear programs needed to represent a given polytope P. In a breakthrough paper Fiorini et al. [Proceedings of 44th ACM Symposium on Theory of Computing 2012, pages 95-106] ... More
Shifted and Shiftless Partition Identities IIMay 12 2006Let S and T be sets of positive integers and let a be a fixed positive integer. An a-shifted partition identity has the form p(S,n)=p(T,n-a), for all n greater or equal to a. Here p(S,n) is the number partitions of n whose parts are elements of S. For ... More
Blow-up results for semilinear wave equations in the super-conformal caseJan 03 2013We consider the semilinear wave equation in higher dimensions with power nonlinearity in the super-conformal range, and its perturbations with lower order terms, including the Klein-Gordon equation. We improve the upper bounds on blow-up solutions previously ... More
BLMA: A Blind Matching Algorithm with Application to Cognitive Radio NetworksMay 01 2016We consider a two-sided matching problem with a defined notion of pairwise stability. We propose a distributed blind matching algorithm (BLMA) to solve the problem. We prove the solution produced by BLMA will converge to an $\epsilon$-pairwise stable ... More
New Results On the Sum of Two Generalized Gaussian Random VariablesMay 31 2015We propose in this paper a new method to compute the characteristic function (CF) of generalized Gaussian (GG) random variable in terms of the Fox H function. The CF of the sum of two independent GG random variables is then deduced. Based on this results, ... More
On Solutions of First Order Stochastic Partial Differential EquationsOct 24 2005This note is concerned with an important for modelling question of existence of solutions of stochastic partial differential equations as proper stochastic processes, rather than processes in the generalized sense. We consider a first order stochastic ... More
A Lyapunov functional and blow-up results for a class of perturbations for semilinear wave equations in the critical caseMay 20 2010May 25 2010We consider in this paper some class of perturbation for the semilinear wave equation with critical (in the conformal transform sense) power nonlinearity. Working in the framework of similarity variables, we find a Lyapunov functional for the problem. ... More
The Gauß-Bonnet operator of an infinite graphJan 04 2013Sep 11 2014We propose a general condition, to ensure essential self-adjointness for the Gau{\ss}-Bonnet operator, based on a notion of completeness as Chernoff. This gives essential self-adjointness of the Laplace operator both for functions or 1-forms on infinite ... More
A framework for reuse of multi-view UML artifactsFeb 02 2014Software is typically modeled from different viewpoints such as structural view, behavioral view and functional view. Few existing works can be considered as applying multi-view retrieval approaches. A number of important issues regarding mapping of entities ... More
The blow-up rate for strongly perturbed semilinear wave equations in the conformal caseOct 23 2014Apr 01 2015We consider in this work some class of strongly perturbed for the semilinear wave equation with conformal power nonlinearity. We obtain an optimal estimate for a radial blow-up solution and we have also obtained two less stronger estimates. These results ... More
Isomorphy up to complementationJan 21 2015Considering uniform hypergraphs, we prove that for every non-negative integer $h$ there exist two non-negative integers $k$ and $t$ with $k\leq t$ such that two $h$-uniform hypergraphs ${\mathcal H}$ and ${\mathcal H}'$ on the same set $V$ of vertices, ... More
Prescribing the center of mass of a multi-soliton solution for a perturbed semilinear wave equationFeb 13 2019We construct a finite-time blow-up solution for a class of strongly perturbed semilinear wave equation with an isolated characteristic point in one space dimension. Given any integer $k\ge 2$ and $\zeta_0 \in \mathbb{R}$, we construct a blow-up solution ... More
A Family of non-Gaussian Martingales with Gaussian MarginalsApr 06 2006We construct a family of non-Gaussian martingales the marginals of which are all Gaussian. We give the predictable quadratic variation of these processes and show they do not have continuous paths. These processes are Markovian and inhomogeneous in time, ... More
Temperature dependent change in the symmetry of the order parameter in an electron-doped high-temperature superconductorFeb 09 2004We present specific heat measurements which show an unexpected phase transition from d-wave symmetry to s-wave symmetry as the temperature is reduced in electron-doped Pr$_{2-x}$Ce$_{x}$CuO$_{4-\delta}$ (PCCO), in both optimal and over-doped single crystals. ... More
Relativistic surfatron process for Landau resonant electrons in radiation beltsFeb 07 2014Recent theoretical studies of the nonlinear wave-particle interactions for relativistic particles have shown that Landau resonant orbits could be efficiently accelerated along the mean background magnetic field for propagation angles $\theta$ in close ... More
Dynamical Systems' approach to relativistic nonlinear wave-particle interaction in weakly collisional plasmasMar 11 2012In this report, we present a dynamical systems' approach to study the exact nonlinear wave-particle interaction in relativistic regime. We give a particular attention to the effect of wave obliquity on the dynamics of the orbits by studying the specific ... More
Relativistic acceleration of Landau resonant particles as a consequence of Hopf bifurcationsApr 25 2011Feb 18 2012Using bifurcation theory on a dynamical system simulating the interaction of a particle with an obliquely propagating wave in relativistic regimes, we demonstrate that uniform acceleration arises as a consequence of Hopf bifurcations of Landau resonant ... More
Lower bounds on nonnegative rank via nonnegative nuclear normsOct 25 2012Jan 29 2015The nonnegative rank of an entrywise nonnegative matrix A of size mxn is the smallest integer r such that A can be written as A=UV where U is mxr and V is rxn and U and V are both nonnegative. The nonnegative rank arises in different areas such as combinatorial ... More
The blow-up rate for strongly perturbed semilinear wave equationsNov 29 2013We consider in this paper a large class of perturbed semilinear wave equation with subconformal power nonlinearity. In particular, we allow log perturbations of the main source. We derive a Lyapunov functional in similarity variables and use it to derive ... More
Self-scaled bounds for atomic cone ranks: applications to nonnegative rank and cp-rankApr 11 2014The nonnegative rank of a matrix A is the smallest integer r such that A can be written as the sum of r rank-one nonnegative matrices. The nonnegative rank has received a lot of attention recently due to its application in optimization, probability and ... More
Claw-freeness, 3-homogeneous subsets of a graph and a reconstruction problemDec 06 2008We describe $Forb\{K_{1,3}, \overline {K_{1,3}}\}$, the class of graphs $G$ such that $G$ and its complement $ \overline{G}$ are claw-free. With few exceptions, it is made of graphs whose connected components consist of cycles of length at least 4, paths ... More
Volatility in options formulae for general stochastic dynamicsJun 05 2013It is well-known that the Black-Scholes formula has been derived under the assumption of constant volatility in stocks. In spite of evidence that this parameter is not constant, this formula is widely used by financial markets. This paper addresses the ... More
Hysteretic response characteristics and dynamic phase transition via site dilution in the kinetic Ising modelJun 23 2012Oct 28 2013The decay of the hysteresis loop area of the system, which is obeying a site diluted kinetic Ising model, is considered by the disorder parameter using the effective field theory analysis. The exhibition focuses on the understanding of external field ... More
A new effective field theory for spin-S (S<=1) dilute Ising ferromagnetsNov 12 2011Site diluted spin-1/2 Ising and spin-1 Blume Capel (BC) models in the presence of transverse field interactions are examined by introducing an effective-field approximation that takes into account the multi-site correlations in the cluster of a considered ... More
Effective field theory analysis of 3D random field Ising model on isometric latticesMar 31 2011Ising model with quenched random magnetic fields is examined for single Gaussian, bimodal and double Gaussian random field distributions by introducing an effective field approximation that takes into account the correlations between different spins that ... More
A note on fractional moments for the one-dimensional continuum Anderson modelJul 27 2009We give a proof of dynamical localization in the form of exponential decay of spatial correlations in the time evolution for the one-dimensional continuum Anderson model via the fractional moments method. This follows via exponential decay of fractional ... More
UML Artifacts Reuse: State of the ArtFeb 02 2014The benefits that can be derived from reusing software include accelerated development, reduced cost, reduced risk and effective use of specialists. Reuse of software artifacts during the initial stages of software development increases reuse benefits, ... More
Polynomial-Time Proactive Synthesis of Tree-to-String Functions from ExamplesJan 16 2017May 24 2017Synthesis from examples enables non-expert users to generate programs by specifying examples of their behavior. A domain-specific form of such synthesis has been recently deployed in a widely used spreadsheet software product. In this paper we contribute ... More
Secure estimation and control for cyber-physical systems under adversarial attacksMay 22 2012The vast majority of today's critical infrastructure is supported by numerous feedback control loops and an attack on these control loops can have disastrous consequences. This is a major concern since modern control systems are becoming large and decentralized ... More
Localization for Random Unitary OperatorsApr 25 2005We consider unitary analogs of $1-$dimensional Anderson models on $l^2(\Z)$ defined by the product $U_\omega=D_\omega S$ where $S$ is a deterministic unitary and $D_\omega$ is a diagonal matrix of i.i.d. random phases. The operator $S$ is an absolutely ... More
Sparse Array DFT Beamformers for Wideband SourcesJan 31 2019Sparse arrays are popular for performance optimization while keeping the hardware and computational costs down. In this paper, we consider sparse arrays design method for wideband source operating in a wideband jamming environment. Maximizing the signal-to-interference ... More
MultiQueues: Simpler, Faster, and Better Relaxed Concurrent Priority QueuesNov 05 2014Priority queues with parallel access are an attractive data structure for applications like prioritized online scheduling, discrete event simulation, or branch-and-bound. However, a classical priority queue constitutes a severe bottleneck in this context, ... More
Random field effects on the phase diagrams of spin-1/2 Ising model on a honeycomb latticeDec 29 2010Ising model with quenched random magnetic fields is examined for single Gaussian, bimodal and double Gaussian random field distributions by introducing an effective field approximation that takes into account the correlations between different spins that ... More
Dynamic phase transition properties and hysteretic behavior of a ferrimagnetic core-shell nanoparticle in the presence of a time dependent magnetic fieldJul 09 2012Nov 16 2012We have presented dynamic phase transition features and stationary-state behavior of a ferrimagnetic small nanoparticle system with a core-shell structure. By means of detailed Monte Carlo simulations, a complete picture of the phase diagrams and magnetization ... More
Novel Network Coding-based Techniques for Multi-layer Video Delivery over Multi-hop Wireless testbedApr 29 2013The actual performance of video delivery over wireless networks is best captured through experimental studies over real testbed, which is crucial to uncover the technical problems and practical challenges of realizing the proposed video delivery techniques. ... More
Monte Carlo simulations of dynamic phase transitions in ferromagnetic thin-filmsJan 26 2015Feb 11 2015By means of detailed Monte Carlo (MC) simulations, we have presented dynamic phase transition (DPT) properties of ferromagnetic thin-films. Thermal variations of surface, bulk and total dynamical order parameters (DOP) for a film and total order parameter ... More
Effective-field theory study of the dynamical Ising-type thin filmsFeb 12 2013Oct 28 2013The stationary state solutions of the Ising-type thin films with different layers in the presence of an external oscillatory field have been examined within the effective field theory. The exhibition focuses on understanding of the external field frequency ... More
Grover's Algorithm and the Secant VarietiesJul 20 2016In this paper we investigate the entanglement nature of quantum states generated by Grover's search algorithm by means of algebraic geometry. More precisely we establish a link between entanglement of states generated by the algorithm and auxiliary algebraic ... More
Time dependent magnetic field effects on the $\pm J$ Ising modelMar 15 2013Apr 26 2013Nonequilibrium phase transition properties of the $\pm J$ Ising model under a time dependent oscillating perturbation are investigated within the framework of effective field theory for a two-dimensional square lattice. After a detailed analysis, it is ... More
Comparaison between the two models : new approach using the $α$-divergenceJan 21 2014We propose new nonparametric accordance R\'enyi-$\alpha$ and $\alpha$-Tsallis divergence estimators for continuous distributions. We discuss this approach with a view to the selection model (on al\'etoire and autoregressive AR (1)). We lestimateur used ... More
Mimicking self-similar processesJun 04 2015We construct a family of self-similar Markov martingales with given marginal distributions. This construction uses the self-similarity and Markov property of a reference process to produce a family of Markov processes that possess the same marginal distributions ... More
Bootstrap Random WalksAug 12 2015Aug 17 2015Consider a one dimensional simple random walk $X=(X_n)_{n\geq0}$. We form a new simple symmetric random walk $Y=(Y_n)_{n\geq0}$ by taking sums of products of the increments of $X$ and study the two-dimensional walk $(X,Y)=((X_n,Y_n))_{n\geq0}$. We show ... More
The Network of Inter-Regional Direct Investment Stocks across EuropeAug 29 2005We propose a methodological framework to study the dynamics of inter-regional investment flow in Europe from a Complex Networks perspective, an approach with recent proven success in many fields including economics. In this work we study the network of ... More
Critical behavior and phase diagrams of a spin-1 Blume-Capel model with random crystal field interactions: An effective field theory analysisJul 21 2011A spin-1 Blume-Capel model with dilute and random crystal fields is examined for honeycomb and square lattices by introducing an effective-field approximation that takes into account the correlations between different spins that emerge when expanding ... More
On scattered posets with finite dimensionDec 06 2008We discuss a possible characterization, by means of forbidden configurations, of posets which are embeddable in a product of finitely many scattered chains.
Claw-freeness, 3-homogeneous subsets of a graph and a reconstruction problemSep 07 2013Sep 22 2013We describe ${\rm Forb}\{K_{1,3}, \bar {K_{1,3}}\}$, the class of graphs $G$ such that $G$ and its complement $\bar{G}$ are claw-free. With few exceptions, it is made of graphs whose connected components consist of cycles of length at least 4, paths, ... More
Diffusive propagation of wave packets in a fluctuating periodic potentialFeb 02 2010Oct 05 2010We consider the evolution of a tight binding wave packet propagating in a fluctuating periodic potential. If the fluctuations stem from a stationary Markov process satisfying certain technical criteria, we show that the square amplitude of the wave packet ... More
Well-Posedness of some nonlinear Volterra-Fredholm integral and integro-dynamic equations on time scalesAug 17 2016In this paper we study well posedness of a certain nonlinear Volterra-Fredholm dynamic integral and integro-dynamic equations on unbounded interval from arbitrary time scale. We derive the time scale analogue of certain integral inequalities of Pachpatte ... More
Dynamic hysteretic features of the Ising-type thin filmsApr 11 2013Aug 01 2014In order to elucidate the important characteristics of hysteretic response, such as types of the frequency dispersion curves, the decay of hysteresis loop area, the mechanism of domain nucleation and/or growth in the dynamic process, etc., a followup ... More
Enabling Minimal Dominating Set in Highly Dynamic Distributed SystemsFeb 02 2015We address the problem of computing a Minimal Dominating Set in highly dynamic distributed systems. We assume weak connectivity, i.e., the network may be disconnected at each time instant and topological changes are unpredictable. We make only weak assumptions ... More
Investigation of bond dilution effects on the magnetic properties of a cylindrical Ising nanowireJun 22 2012A cylindrical magnetic nanowire system composed of ferromagnetic core and shell layers has been investigated by using effective field theory with correlations. Both ferromagnetic and antiferromagnetic exchange couplings at the core-shell interface have ... More
Structural Synthesis for GXW SpecificationsMay 04 2016Jul 06 2016We define the GXW fragment of linear temporal logic (LTL) as the basis for synthesizing embedded control software for safety-critical applications. Since GXW includes the use of a weak-until operator we are able to specify a number of diverse programmable ... More
Equivariant semidefinite lifts of regular polygonsSep 15 2014Given a polytope P in $\mathbb{R}^n$, we say that P has a positive semidefinite lift (psd lift) of size d if one can express P as the linear projection of an affine slice of the positive semidefinite cone $\mathbf{S}^d_+$. If a polytope P has symmetry, ... More
Rational and real positive semidefinite rank can be differentApr 18 2014Given a nonnegative matrix M with rational entries, we consider two quantities: the usual positive semidefinite (psd) rank, where the matrix is factored through the cone of real symmetric psd matrices, and the rational-restricted psd rank, where the matrix ... More
On the Establishment, Persistence, and Inevitable Extinction of PopulationsOct 11 2014Comprehensive models of stochastic, clonally reproducing populations are defined in terms of general branching processes, allowing birth during maternal life, as for higher organisms, or by splitting, as in cell division. The populations are assumed to ... More
Reinforcement Learning for Transition-Based Mention DetectionMar 13 2017This paper describes an application of reinforcement learning to the mention detection task. We define a novel action-based formulation for the mention detection task, in which a model can flexibly revise past labeling decisions by grouping together tokens ... More
Dynamical Localization in Disordered Quantum Spin SystemsAug 18 2011Mar 20 2012We say that a quantum spin system is dynamically localized if the time-evolution of local observables satisfies a zero-velocity Lieb-Robinson bound. In terms of this definition we have the following main results: First, for general systems with short ... More
Dynamical Localization for Unitary Anderson ModelsFeb 28 2009This paper establishes dynamical localization properties of certain families of unitary random operators on the d-dimensional lattice in various regimes. These operators are generalizations of one-dimensional physical models of quantum transport and draw ... More
Asymptotic behaviour of the fractional Heston modelNov 27 2014We consider here the fractional version of the Heston model originally proposed by Comte, Coutin and Renault. Inspired by some recent ground-breaking work by Gatheral, Jaisson and Rosenbaum, who showed that fractional Brownian motion with short memory ... More
Sparse sum-of-squares certificates on finite abelian groupsMar 04 2015Let G be a finite abelian group. This paper is concerned with nonnegative functions on G that are sparse with respect to the Fourier basis. We establish combinatorial conditions on subsets S and T of Fourier basis elements under which nonnegative functions ... More
Equivariant semidefinite lifts and sum-of-squares hierarchiesDec 23 2013Apr 15 2015A central question in optimization is to maximize (or minimize) a linear function over a given polytope P. To solve such a problem in practice one needs a concise description of the polytope P. In this paper we are interested in representations of P using ... More
Bilateral Multi-Perspective Matching for Natural Language SentencesFeb 13 2017Jul 14 2017Natural language sentence matching is a fundamental technology for a variety of tasks. Previous approaches either match sentences from a single direction or only apply single granular (word-by-word or sentence-by-sentence) matching. In this work, we propose ... More