Results for "Mohammed Lemou"

total 1412took 0.11s
Micro-macro schemes for kinetic equations including boundary layersFeb 09 2012We introduce a new micro-macro decomposition of collisional kinetic equations in the specific case of the diffusion limit, which naturally incorporates the incoming boundary conditions. The idea is to write the distribution function $f$ in all its domain ... More
A boundary matching micro/macro decomposition for kinetic equationsDec 14 2010Feb 21 2011We introduce a new micro/macro decomposition of collisional kinetic equations which naturally incorporates the exact space boundary conditions. The idea is to write the distribution fonction $f$ in all its domain as the sum of a Maxwellian adapted to ... More
Orbital stability of spherical galactic modelsJul 23 2010We consider the three dimensional gravitational Vlasov Poisson system which is a canonical model in astrophysics to describe the dynamics of galactic clusters. A well known conjecture is the stability of spherical models which are nonincreasing radially ... More
A new variational approach to the stability of gravitational systemsApr 16 2009Mar 05 2010We consider the three dimensional gravitational Vlasov Poisson system which describes the mechanical state of a stellar system subject to its own gravity. A well-known conjecture in astrophysics is that the steady state solutions which are nonincreasing ... More
Extended Rearrangement inequalities and applications to some quantitative stability resultsSep 28 2015In this paper, we prove a new functional inequality of Hardy-Littlewood type for generalized rearrangements of functions. We then show how this inequality provides {\em quantitative} stability results of steady states to evolution systems that essentially ... More
Escape of stars from gravitational clusters in the Chandrasekhar modelMar 26 2010We study the evaporation of stars from globular clusters using the simplified Chandrasekhar model. This is an analytically tractable model giving reasonable agreement with more sophisticated models that require complicated numerical integrations. In the ... More
Relaxation of the distribution function tails for systems described by Fokker-Planck equationsJun 21 2005Oct 19 2005We study the formation and the evolution of velocity distribution tails for systems with long-range interactions. In the thermal bath approximation, the evolution of the distribution function of a test particle is governed by a Fokker-Planck equation ... More
Multiscale numerical schemes for kinetic equations in the anomalous diffusion limitMay 13 2015We construct numerical schemes to solve kinetic equations with anomalous diffusion scaling. When the equilibrium is heavy-tailed or when the collision frequency degenerates for small velocities, an appropriate scaling should be made and the limit model ... More
Stable Ground States for the HMF Poisson ModelSep 07 2017Sep 11 2017In this paper we prove the nonlinear orbital stability of a large class of steady states solutions to the Hamiltonian Mean Field (HMF) system with a Poisson interaction potential. These steady states are obtained as minimizers of an energy functional ... More
Chapman-Enskog derivation of the generalized Smoluchowski equationMar 24 2004We use the Chapman-Enskog method to derive the Smoluchowski equation from the Kramers equation in a high friction limit. We consider two main extensions of this problem: we take into account a uniform rotation of the background medium and we consider ... More
Nonlinear instability of inhomogeneous steady states solutions to the HMF ModelFeb 26 2019In this work we prove the nonlinear instability of inhomogeneous steady states solutions to the Hamiltonian Mean Field (HMF) model. We first study the linear instability of this model under a simple criterion by adapting the techniques developed in [19]. ... More
A particle micro-macro decomposition based numerical scheme for collisional kinetic equations in the diffusion scalingJan 18 2017In this work, we derive particle schemes, based on micro-macro decomposition, for linear kinetic equations in the diffusion limit. Due to the particle approximation of the micro part, a splitting between the transport and the collision part has to be ... More
Nonlinear stability criteria for the HMF ModelSep 29 2015We study the nonlinear stability of a large class of inhomogeneous steady state solutions to the Hamiltonian Mean Field (HMF) model. Under a simple criterion, we prove the nonlinear stability of steady states which are decreasing functions of the microscopic ... More
An averaging technique for transport equationsSep 30 2016In this paper, we develop a new strategy aimed at obtaining high-order asymptotic models for transport equations with highly-oscillatory solutions. The technique relies upon averaging theory for ordinary differential equations, in particular normal form ... More
Stable ground states for the relativistic gravitational Vlasov-Poisson systemFeb 05 2009We consider the three dimensional gravitational Vlasov-Poisson (GVP) system in both classical and relativistic cases. The classical problem is subcritical in the natural energy space and the stability of a large class of ground states has been derived ... More
Numerical schemes for kinetic equations in the diffusion and anomalous diffusion limits. Part I: the case of heavy-tailed equilibriumMar 16 2015In this work, we propose some numerical schemes for linear kinetic equations in the diffusion and anomalous diffusion limit. When the equilibrium distribution function is a Maxwellian distribution, it is well known that for an appropriate time scale, ... More
Averaging of highly-oscillatory transport equationsSep 30 2016Nov 14 2016In this paper, we develop a new strategy aimed at obtaining high-order asymptotic models for transport equations with highly-oscillatory solutions. The technique relies upon recent developments averaging theory for ordinary differential equations, in ... More
Stable ground states and self-similar blow-up solutions for the gravitational Vlasov-Manev systemJun 01 2010Nov 14 2012In this work, we study the orbital stability of steady states and the existence of blow-up self-similar solutions to the so-called Vlasov-Manev (VM) system. This system is a kinetic model which has a similar Vlasov structure as the classical Vlasov-Poisson ... More
Models of dark matter halos based on statistical mechanics: II. The fermionic King modelSep 27 2014We discuss the nature of phase transitions in the fermionic King model which describes tidally truncated quantum self-gravitating systems. This distribution function takes into account the escape of high energy particles and has a finite mass. On the ... More
Asymptotic preserving schemes for highly oscillatory kinetic equationOct 17 2012This work is devoted to the numerical simulation of a Vlasov-Poisson model describing a charged particle beam under the action of a rapidly oscillating external electric field. We construct an Asymptotic Preserving numerical scheme for this kinetic equation ... More
Nonlinear Geometric Optics method based multi-scale numerical schemes for highly-oscillatory transport equationsMay 31 2016We introduce a new numerical strategy to solve a class of oscillatory transport PDE models which is able to captureaccurately the solutions without numerically resolving the high frequency oscillations {\em in both space and time}.Such PDE models arise ... More
The fermionic King modelNov 22 2014We study the fermionic King model which may provide a relevant model of dark matter halos. The exclusion constraint can be due to quantum mechanics (for fermions such as massive neutrinos) or to Lynden-Bell's statistics (for collisionless systems undergoing ... More
Asymptotic Preserving numerical schemes for multiscale parabolic problemsJul 23 2015Nov 20 2015We consider a class of multiscale parabolic problems with diffusion coefficients oscillating in space at a possibly small scale $\varepsilon$. Numerical homogenization methods are popular for such problems, because they capture efficiently the asymptotic ... More
Uniformly accurate numerical schemes for the nonlinear Dirac equation in the nonrelativistic limit regimeMay 09 2016We apply the two-scale formulation approach to propose uniformly accurate (UA) schemes for solving the nonlinear Dirac equation in the nonrelativistic limit regime. The nonlinear Dirac equation involves two small scales $\varepsilon$ and $\varepsilon^2$ ... More
Models of dark matter halos based on statistical mechanics: I. The classical King modelSep 27 2014We consider the possibility that dark matter halos are described by the Fermi-Dirac distribution at finite temperature. This is the case if dark matter is a self-gravitating quantum gas made of massive neutrinos at statistical equilibrium. This is also ... More
Nonlinear instability of inhomogeneous steady states solutions to the HMF ModelFeb 26 2019Apr 01 2019In this work we prove the nonlinear instability of inhomogeneous steady states solutions to the Hamiltonian Mean Field (HMF) model. We first study the linear instability of this model under a simple criterion by adapting the techniques developed in [19]. ... More
Uniformly accurate numerical schemes for the nonlinear Dirac equation in the nonrelativistic limit regimeMay 09 2016Dec 17 2016We apply the two-scale formulation approach to propose uniformly accurate (UA) schemes for solving the nonlinear Dirac equation in the nonrelativistic limit regime. The nonlinear Dirac equation involves two small scales $\varepsilon$ and $\varepsilon^2$ ... More
A new class of uniformly accurate numerical schemes for highly oscillatory evolution equationsDec 18 2017We introduce a new methodology to design uniformly accurate methods for oscillatory evolution equations. The targeted models are envisaged in a wide spectrum of regimes, from non-stiff to highly-oscillatory. Thanks to an averaging transformation, the ... More
Nonlinear Geometric Optics Based Multiscale Stochastic Galerkin Methods for Highly Oscillatory Transport Equations with Random InputsApr 04 2017We develop generalized polynomial chaos (gPC) based stochastic Galerkin (SG) methods for a class of highly oscillatory transport equations that arise in semiclassical modeling of non-adiabatic quantum dynamics. These models contain uncertainties, particularly ... More
Uniformly accurate methods for three dimensional Vlasov equations under strong magnetic field with varying directionJul 10 2019In this paper, we consider the three dimensional Vlasov equation with an inhomogeneous, varying direction, strong magnetic field. Whenever the magnetic field has constant intensity, the oscillations generated by the stiff term are periodic. The homogenized ... More
Uniformly accurate numerical schemes for highly oscillatory Klein-Gordon and nonlinear Schrödinger equationsAug 02 2013This work is devoted to the numerical simulation of nonlinear Schr\"odinger and Klein-Gordon equations. We present a general strategy to construct numerical schemes which are uniformly accurate with respect to the oscillation frequency. This is a stronger ... More
Uniformly accurate methods for Vlasov equations with non-homogeneous strong magnetic fieldFeb 08 2018In this paper, we consider the numerical solution of highly-oscillatory Vlasov and Vlasov-Poisson equations with non-homogeneous magnetic field. Designed in the spirit of recent uniformly accurate methods, our schemes remain insensitive to the stiffness ... More
A new class of uniformly accurate numerical schemes for highly oscillatory evolution equationsDec 18 2017Jan 10 2019We introduce a new methodology to design uniformly accurate methods for oscillatory evolution equations. The targeted models are envisaged in a wide spectrum of regimes, from non-stiff to highly-oscillatory. Thanks to an averaging transformation, the ... More
Highly-oscillatory problems with time-dependent vanishing frequencyJul 20 2018In the analysis of highly-oscillatory evolution problems, it is commonly assumed that a single frequency is present and that it is either constant or, at least, bounded from below by a strictly positive constant uniformly in time. Allowing for the possibility ... More
Some Uniform Limit Results in Additive Regression ModelJun 08 2007We establish some uniform limit results in the setting of additive regression model estimation. Our results allow to give an asymptotic 100% confidence bands for these components. These results are stated in the framework of i.i.d random vectors when ... More
From string theory to large N QCDDec 13 2010We propose the dual gravity of a non conformal gauge theory which has logarithmic running of couplings in the IR but becomes almost conformal in the far UV. The theory has matter in fundamental representation, non-zero temperature and under a cascade ... More
A trace formula for the index of B-Fredholm operatorsSep 06 2016In this paper we define B-Fredholm elements in a Banach algebra $A$ modulo an ideal $J$ of $A.$ When a trace function is given on the ideal $J,$ it generate an index for B-Fredholm elements. In the case of a B-Fredholm operator $T$ acting on a Banach ... More
Towards Green and Infinite Capacity in Wireless Communication Networks: Beyond The Shannon TheoremJul 14 2015New and novel way for resources allocation in wireless communication has been proposed in this paper. Under this new method, it has been shown that the required power budget becomes independent of the number of served terminals in the downlink. However, ... More
On representations of isometric isomorphisms between some monoid of functionsOct 10 2016We prove that each isometric isomorphism, between the monoids of all nonegative 1-Lipschitz maps defined on invariant metric groups and equiped with the inf-convolution law, is given canonically from an isometric isomorphism between their groups of units. ... More
Any law of group metric invariant is an inf-convolutionJul 02 2015In this article, we bring a new light on the concept of the inf-convolution operation $\oplus$ and provides additional informations to the work started in \cite{Ba1} and \cite{Ba2}. It is shown that any internal law of group metric invariant (even quasigroup) ... More
On cubic Thue equations and the common index divisors of cyclic cubic fieldsJan 07 2018Jan 12 2018In this paper, we investigate the common index divisors of cyclic cubic fields. Let $a,b,c,d$ and $k$ are integers, we then solve the following Thue cubic equations:: \[ax^3+bx^2y+cxy^2+dy^3= k\ \] when $a,bc+d$ are odd and $3$ doesn't divide $v_2(k)$. ... More
The Cover Time of Random Walks on GraphsFeb 24 2012A simple random walk on a graph is a sequence of movements from one vertex to another where at each step an edge is chosen uniformly at random from the set of edges incident on the current vertex, and then transitioned to next vertex. Central to this ... More
Extension Of The Bauer's Maximum Principle For Compact Metrizable SetsDec 18 2018Let X be a nonempty convex compact subset of some Haus-dorff locally convex topological vector space S. The well know Bauer's maximum principle stats that every convex upper semi-continuous function from X into R attains its maximum at some extremal point ... More
Homogeneous coordinate rings and mirror symmetry for toric varietiesNov 26 2005Mar 01 2009Given a smooth toric variety X and an ample line bundle O(1), we construct a sequence of Lagrangian submanifolds of (C^*)^n with boundary on a level set of the Landau-Ginzburg mirror of X. The corresponding Floer homology groups form a graded algebra ... More
Classification of complete left-invariant affine structures on the Oscillator groupDec 30 2012Apr 30 2013The goal of this paper is to provide a method, based on the theory of extensions of left-symmetric algebras, for classifying left-invariant affine structures on a given solvable Lie group of low dimension. To better illustrate our method, we shall apply ... More
The family Floer functor is faithfulAug 28 2014Jul 11 2016Family Floer theory yields a functor from the Fukaya category of a symplectic manifold admitting a Lagrangian torus fibration to a (twisted) category of perfect complexes on the mirror rigid analytic space. This functor is shown to be faithful by a degeneration ... More
Family Floer cohomology and mirror symmetryApr 10 2014Ideas of Fukaya and Kontsevich-Soibelman suggest that one can use Strominger-Yau-Zaslow's geometric approach to mirror symmetry as a torus duality to construct the mirror of a symplectic manifold equipped with a Lagrangian torus fibration as a moduli ... More
A cotangent fibre generates the Fukaya categoryMar 23 2010Jun 07 2011We prove that the algebra of chains on the based loop space recovers the derived (wrapped) Fukaya category of the cotangent bundle of a closed smooth orientable manifold. The main new idea is the proof that a cotangent fibre generates the Fukaya category ... More
Brownian bridge with random length and pinning point for modelling of financial informationJul 18 2019Developed countries are increasingly relying on gas storage to ensure security of supply. In this article we consider an approach to gas storage valuation in which the information about the time at which the holder of a gas storage contract should choose ... More
Stabilité et simplicité positiveApr 19 2012We study extensions universal positive model theory. And we continue the study of stability and simplicity already initiated by Ben Yaacov.
On $p-$RingJul 03 2011In this paper, we introduced the concept of a $p$-ideal for a given ring. We provide necessary and sufficient condition for $\dfrac{R[x]}{(f(x))}$ to be a $p$-ring, where $R$ is a finite $p$-ring. It is also shown that the amalgamation of rings, $A\bowtie^fJ$ ... More
Representations of Generalized a$_r$ Statistics and Eigenstates of Jacobson GeneratorsJun 20 2006We investigate a generalization of $A_r$ statistics discussed recently in the literature. The explicit complete set of state vectors for the $A_r$ statistics system is given. We consider a Bargmann or an analytic function description of the Fock space ... More
Molecular Dynamics and Monte-Carlo Simulations of CoPt alloysFeb 07 2006Feb 14 2006November 2002, "Magister", Supervisors : Dr. H. Bouzar (Tizi-Ouzou, Algeria) with the collaboration of Dr. V. Pierron-Bohnes and Dr. C. Goyhenex (Strasbourg, France). Mouloud Mammeri University, Tizi-Ouzou (Algeria) and Louis Pasteur University, Strasbourg ... More
Counting Hexagonal Lattice AnimalsFeb 27 2002Feb 28 2009We describe Maple packages for the automatic generation of generating functions(and series expansions) for counting lattice animals(fixed polyominoes), in the two-dimensional hexagonal lattice, of bounded but arbitrary width. Our Maple packages(complete ... More
Symplectic cohomology and Viterbo's theoremDec 11 2013Jan 25 2014This is a research monograph on symplectic cohomology (disguised as an advanced graduate textbook), which provides a construction of this version of Hamiltonian Floer cohomology for cotangent bundles of closed manifolds. The focus is on the aspects of ... More
Nodal solutions to quasilinear elliptic equations on compact Riemannian manifoldsOct 06 2007We show the existence of nodal solutions to perturbed quasilinear elliptic equations with critical Sobolev exponent on compact Riemannian manifolds. A nonexistence result is also given.
Borel Spectrum of Operators on Banach SpacesDec 30 2009The paper investigates the variation of the spectrum of operators in infinite dimensional Banach spaces. In particular, it is shown that the spectrum function is Borel from the space of bounded operators on a separable Banach space; equipped with the ... More
Literature Review Of Attribute Level And Structure Level Data Linkage TechniquesOct 07 2015Data Linkage is an important step that can provide valuable insights for evidence-based decision making, especially for crucial events. Performing sensible queries across heterogeneous databases containing millions of records is a complex task that requires ... More
Information Analysis of DNA SequencesOct 15 2010The problem of differentiating the informational content of coding (exons) and non-coding (introns) regions of a DNA sequence is one of the central problems of genomics. The introns are estimated to be nearly 95% of the DNA and since they do not seem ... More
TCP Congestion Control IdentificationNov 13 2014Transmission Control Protocol (TCP) carries most of the traffic on the Internet these days. There are several implementations of TCP, and the most important difference among them is their mechanism for controlling congestion. One of the methods for determining ... More
Morse Homology, Tropical Geometry, and Homological Mirror Symmetry for Toric VarietiesSep 29 2006Apr 21 2009Given a smooth projective toric variety X, we construct an A-infinity category of Lagrangians with boundary on a level set of the Landau-Ginzburg mirror of X. We prove that this category is quasi-equivalent to the DG category of line bundles on X. This ... More
Ruled surfaces of finite type in 3-dimensional Heisenberg groupMay 17 2016In this paper, on the first, we prove $\Delta r=2H$ where $\Delta $ is the Laplacian operator, $r=\left( r_{1},r_{2},r_{3}\right) $ the position vector field and $H$ is the mean curvature vector field of a surface $\mathcal{S}$ in the 3-dimensional Heisenberg ... More
Homological mirror symmetry without correctionsMar 23 2017Let X be a closed symplectic manifold equipped a Lagrangian torus fibration. A construction first considered by Kontsevich and Soibelman produces from this data a rigid analytic space, which can be considered as a variant of the T-dual introduced by Strominger, ... More
A Coanalytic Rank on Super-Ergodic OperatorsDec 29 2009Techniques from Descriptive Set Theory are applied in order to study the Topological Complexity of families of operators naturally connected to ergodic operators in infinite dimensional Banach Spaces. The families of ergodic, uniform-ergodic,Cesaro-bounded ... More
On the wrapped Fukaya category and based loopsJul 31 2009Oct 11 2010Given an exact relatively Pin Lagrangian embedding Q in a symplectic manifold M, we construct an A-infinity restriction functor from the wrapped Fukaya category of M to the category of modules on the differential graded algebra of chains over the based ... More
Abstract Weyl-type TheoremsApr 11 2013In this paper, we give a new approach for the study of Weyl-type theorems. Precisely we introduce the concepts of spectral valued and spectral partitioning functions. Using two natural order relations on the set of spectral valued functions, we reduce ... More
ProteinNet: a standardized data set for machine learning of protein structureFeb 01 2019Rapid progress in deep learning has spurred its application to bioinformatics problems including protein structure prediction and design. In classic machine learning problems like computer vision, progress has been driven by standardized data sets that ... More
On a remarkable class of left-symmetric algebras and its relationship with the class of Novikov algebrasDec 17 2012Jul 23 2013We discuss locally simply transitive affine actions of Lie groups G on finite-dimensional vector spaces such that the commutator subgroup [G,G] is acting by translations. In other words, we consider left-symmetric algebras satisfying the identity [x,y].z=0. ... More
Colored Image Encryption and Decryption Using Chaotic Lorenz System and DCT2Jan 11 2017In this paper, a scheme for the encryption and decryption of colored images by using the Lorenz system and the discrete cosine transform in two dimensions (DCT2) is proposed. Although chaos is random, it has deterministic features that can be used for ... More
Nearby Lagrangians with vanishing Maslov class are homotopy equivalentMay 03 2010Oct 17 2011We prove that the inclusion of every closed exact Lagrangian with vanishing Maslov class in a cotangent bundle is a homotopy equivalence. We start by adapting an idea of Fukaya-Seidel-Smith to prove that such a Lagrangian is equivalent to the zero section ... More
A geometric criterion for generating the Fukaya categoryJan 26 2010Sep 29 2010Given a collection of exact Lagrangians in a Liouville manifold, we construct a map from the Hochschild homology of the Fukaya category that they generate to symplectic cohomology. Whenever the identity in symplectic cohomology lies in the image of this ... More
On the B-discrete spectrumJun 12 2016Jul 18 2019In this paper, we introduce the B-discrete spectrum of an unbounded closed operator and we prove that a closed operator has a purely B-discrete spectrum if and only if it has a meromorphic resolvent. After that, we study the stability of the B-discrete ... More
Maximality of Linear OperatorsNov 01 2017We present maximality results in the setting of non necessarily bounded operators. In particular, we discuss and establish results showing when the "inclusion" between operators becomes a full equality.
B-discrete spectrum and operators with meromorphic or Riesz resolventJun 12 2016In this paper, we introduce the B-discrete spectrum of an unbounded closed operator. Then we prove that a closed operator has a purely B-discrete spectrum if and only if it has a meromorphic resolvent. We will consider also operators with Riesz resolvent ... More
A topological model for the Fukaya categories of plumbingsApr 09 2009Jul 28 2010We prove that the algebra of singular cochains on a smooth manifold, equipped with the cup product, is equivalent to the A-infinity structure on the Lagrangian Floer cochain group associated to the zero section in the cotangent bundle. More generally, ... More
On the Fukaya Categories of Higher Genus SurfacesJun 23 2006Aug 30 2007We construct the Fukaya category of a closed surface equipped with an area form using only elementary (essentially combinatorial) methods. We also compute the Grothendieck group of its derived category.
On Generalized West and Stampfli Decomposition of OperatorsJun 12 2016Apr 25 2017In this paper, we characterize meromorphic operators in terms of B-Fredholm operators and operators of topological uniform descent. Using those characterizations, we recover several new results and earlier results on meromorphic operators established ... More
On singular Q-curvature type equationsOct 02 2010Oct 23 2012This paper is devoted to the Q-curvature type equation with singularities; mainly we give existence and regularity results of solutions. To have positive solutions which will be meaningfully in conformal geometry we restrict ourself to special manifolds. ... More
Existence and mutiplicity of solutions to elliptic equations of fourth order on compact manifoldsSep 30 2007Oct 02 2010This paper deals with a fourth order elliptic equation on compact Riemannian manifolds.We establish the existence of solutions to the equation with critical Sobolev growth which is the subject of the first theorem. In the second one, we prove the multiplicity ... More
Framed bordism and Lagrangian embeddings of exotic spheresDec 29 2008Jan 03 2011In dimensions congruent to 1 modulo 4, we prove that the cotangent bundle of an exotic sphere which does not bound a parallelisable manifold is not symplectomorphic to the cotangent bundle of the standard sphere. More precisely, we prove that such an ... More
Robustesse de la stabilité globale asymptotique des équilibres pour les systèmes dynamiques dissipatifs perturbésOct 11 2017In this paper, we'll show the robustness of global stability for perturbed dissipative dynamical systems.
A Light Weight Protocol to Provide Location Privacy in Wireless Body Area networksMar 16 2011Location privacy is one of the major security problems in a Wireless Body Area Networks (WBANs). An eavesdropper can keep track of the place and time devices are communicating. To make things even worse, the attacker does not have to be physically close ... More
Using Arabic Wordnet for semantic indexation in information retrieval systemJun 11 2013Jun 19 2013In the context of arabic Information Retrieval Systems (IRS) guided by arabic ontology and to enable those systems to better respond to user requirements, this paper aims to representing documents and queries by the best concepts extracted from Arabic ... More
On the Morse index of harmonic maps and minimal immersionsApr 15 2010In this paper we are concerned with harmonic maps and minimal immersions defined on compact Riemannian manifolds and with values in homogenous strongly harmonic manifolds. We show some results on the Morse index by varying these maps along suitable conformal ... 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
Quantum Hall Effect on the Flag Manifold F_2Oct 13 2006May 06 2008The Landau problem on the flag manifold ${\bf F}_2 = SU(3)/U(1)\times U(1)$ is analyzed from an algebraic point of view. The involved magnetic background is induced by two U(1) abelian connections. In quantizing the theory, we show that the wavefunctions, ... More
Effective Wess-Zumino-Witten Action for Edge States of Quantum Hall Systems on Bergman BallMay 30 2006Apr 23 2007Using a group theory approach, we investigate the basic features of the Landau problem on the Bergman ball {\bf B}^k. This can be done by considering a system of particles living on {\bf B}^k in the presence of an uniform magnetic field B and realizing ... More
Effective field approach to the Ising film in a transverse fieldSep 23 1998We study the phase transitions of the spin-1/2 Ising film in a transverse field within the framework of the effective field theory. We evaluate the critical temperature of the film as a function of the exchange interactions, the transverse field and the ... More
On valuation ringsJun 24 2009In this paper we provide necessary and sufficient conditions for $ R=A\propto E $ to be a valuation ring where $E$ is a non-torsion or finitely generated $A-$module. Also, we investigate the $ (n,d) $ property of the valuation ring.
Strongly $n$-Gorenstein projective, injective and flat modulesApr 26 2009This paper generalize the idea of the authors in \cite{Bennis and Mahdou1}. Namely, we define and study a particular case of modules with Gorenstein projective, injective, and flat dimension less or equal than $n\geq 0$, which we call, respectively, strongly ... More
Additive Regression Model for Continuous Time ProcessesJun 08 2007In the setting of additive regression model for continuous time process, we establish the optimal uniform convergence rates and optimal asymptotic quadratic error of additive regression. To build our estimate, we use the marginal integration method.
Manifold Learning Using Kernel Density Estimation and Local Principal Components AnalysisSep 11 2017We consider the problem of recovering a $d-$dimensional manifold $\mathcal{M} \subset \mathbb{R}^n$ when provided with noiseless samples from $\mathcal{M}$. There are many algorithms (e.g., Isomap) that are used in practice to fit manifolds and thus reduce ... More
A supervised machine learning estimator for the non-linear matter power spectrum - SEMPSJul 16 2015In this article, we argue that models based on machine learning (ML) can be very effective in estimating the non-linear matter power spectrum ($P(k)$). We employ the prediction ability of the supervised ML algorithms to build an estimator for the $P(k)$. ... More
Experimental Report on Setting up a Cloud Computing Environment at the University of BradfordDec 15 2014Cloud computing is increasingly attracting large attention in computing both in academic research and in industrial initiatives. Emerging as a popular paradigm and an attractive model of providing computing, information technology (IT) infrastructure, ... More
An Automatic Seeded Region Growing for 2D Biomedical Image SegmentationDec 12 2014In this paper, an automatic seeded region growing algorithm is proposed for cellular image segmentation. First, the regions of interest (ROIs) extracted from the preprocessed image. Second, the initial seeds are automatically selected based on ROIs extracted ... More
On the Invertibility of the Sum of OperatorsApr 19 2018Oct 03 2018The primary purpose of this paper is to investigate the question of invertibility of the sum of operators. The setting is bounded and unbounded linear operators. Some interesting examples and consequences are given. As an illustrative point, we characterize ... More
On the Existence of Normal Square and Nth Roots of OperatorsJan 21 2018Mar 22 2018The primary purpose of this paper is to show the existence of normal square and nth roots of some classes of bounded operators on Hilbert spaces. Two interesting simple results hold. Namely, under simple conditions we show that if any operator $T$ is ... More
Simultaneous sign change and equidistribution of signs of Fourier coefficients of two cusp formsNov 06 2017May 23 2018We study the simultaneous sign change of Fourier coefficients of a pair of distinct normalized newforms of integral weight supported on primes power indices, we also prove some equidistribution results. Finally, we consider an analogous question for Fourier ... More
Band splitting in bilayer stanene electronic structure scrutinized via first principle DFT calculationsOct 16 2017Jan 23 2019The recent work on stanene as quantum spin Hall insulators made us investigate bilayer stanene using first principle calculations. With an aim of improving and developing new properties, via modulating the stacking order (and angle) of the bilayers. This ... More
A Contribution to the Fong-Tsui Conjecture Related to Self-adjoint OperatorsAug 21 2012We are interested in an open question raised by Fong-Tsui (dating back to the beginning of the eighties of last century) as to whether a bounded operator whose absolute value is less than the absolute value of its real part is self-adjoint. The analogue ... More