Results for "Dimitri N. Laikov"

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Additive atomic approximation for relativistic effects: a two-component Hamiltonian for molecular electronic structure calculationsNov 20 2018An approximate relativistic two-component Hamiltonian for use in molecular electronic structure calculations is derived in the form of a sum of fixed atom-centered kinetic and spin-orbit operators added to the non-relativistic Hamiltonian. Starting from ... More
A new parametrizable model of molecular electronic structureJun 23 2011Aug 29 2011A new electronic structure model is developed in which the ground state energy of a molecular system is given by a Hartree-Fock-like expression with parametrized one- and two-electron integrals over an extended (minimal + polarization) set of orthogonalized ... More
Atomic basis functions for molecular electronic structure calculationsAug 16 2018Electronic structure methods for accurate calculation of molecular properties have a high cost that grows steeply with the problem size, therefore, it is helpful to have the underlying atomic basis functions that are less in number but of higher quality. ... More
Simple exchange hole models for long-range-corrected density functionalsMay 20 2019Density functionals with a range-separated treatment of the exchange energy are known to improve upon their semilocal forerunners and fixed-fraction hybrids. The conversion of a given semilocal functional into its short-range analog is not straightforward, ... More
A reversible numerical integrator of the isokinetic equations of motionSep 17 2017Oct 30 2018An explicit second-order numerical method to integrate the isokinetic equations of motion is derived by fitting circular arcs through every three consecutive points of the discretized trajectory, so that the tangent and the curvature satisfy the equations ... More
Atomic effective potentials for starting molecular electronic structure calculationsFeb 08 2019Mar 06 2019Atomic effective one-electron potentials in a compact analytic form in terms of a few Gaussian charge distributions are developed, for Hydrogen through Nobelium, for starting molecular electronic structure calculations by a simple diagonalization. For ... More
Combination of many-body and density-functional theoriesJun 14 2011A framework for developing new approximate electronic structure methods is presented, in which the correlation energy of a many-electron system in the ground state is computed as in the single-reference second-order many-body perturbation theory but with ... More
Atomic effective potentials for starting molecular electronic structure calculationsFeb 08 2019Molecular electronic structure calculations can be easily started by diagonalizing a one-electron Hamiltonian based on a sum of fixed atomic effective potentials. For the latter, we have found compact analytic forms in terms of a few Gaussian functions ... More
"New Cybernetics and the Application of its Principles in Physics" and "Comment on "Quantum Solution to the Arrow-of-Time Dilemma" of L. Maccone arXiv:0802.0438"Nov 13 2009Sep 18 2013The first paper: We describe principles of new cybernetics and use these principles for resolution of basic physical paradoxes. It demonstrates universality of the principles of new cybernetics. The second paper: recent letter by Maccone presents a solution ... More
Nonparametric estimation of the conditional distribution at regression boundary pointsApr 03 2017Nonparametric regression is a standard statistical tool with increased importance in the Big Data era. Boundary points pose additional difficulties but local polynomial regression can be used to alleviate them. Local linear regression, for example, is ... More
Covariance matrix estimation and linear process bootstrap for multivariate time series of possibly increasing dimensionJun 02 2015Multivariate time series present many challenges, especially when they are high dimensional. The paper's focus is twofold. First, we address the subject of consistently estimating the autocovariance sequence; this is a sequence of matrices that we conveniently ... More
Greedy AutoAugmentAug 02 2019A major problem in data augmentation is the number of possibilities in the search space of operations. The search space includes mixtures of all of the possible data augmentation techniques, the magnitude of these operations, and the probability of applying ... More
Track Facial Points in Unconstrained VideosSep 09 2016Tracking Facial Points in unconstrained videos is challenging due to the non-rigid deformation that changes over time. In this paper, we propose to exploit incremental learning for person-specific alignment in wild conditions. Our approach takes advantage ... More
Waveform Design for Secure SISO Transmissions and MulticastingJun 03 2013Wireless physical-layer security is an emerging field of research aiming at preventing eavesdropping in an open wireless medium. In this paper, we propose a novel waveform design approach to minimize the likelihood that a message transmitted between trusted ... More
Convolved subsampling estimation with applications to block bootstrapJun 22 2017The block bootstrap approximates sampling distributions from dependent data by resampling data blocks. A fundamental problem is establishing its consistency for the distribution of a sample mean, as a prototypical statistic. We use a structural relationship ... More
Moduli of continuity and average decay of Fourier transforms: two-sided estimatesDec 18 2002Jun 29 2007We study inequalities between general integral moduli of continuity of a function and the tail integral of its Fourier transform. We obtain, in particular, a refinement of a result due to D. B. H. Cline [2] (Theorem 1.1 below). We note that our approach ... More
Sequential and asynchronous processes driven by stochastic or quantum grammars and their application to genomics: a surveyNov 14 2005We present the formalism of sequential and asynchronous processes defined in terms of random or quantum grammars and argue that these processes have relevance in genomics. To make the article accessible to the non-mathematicians, we keep the mathematical ... More
Two-Body Random Ensembles: From Nuclear Spectra to Random PolynomialsSep 26 2000The two-body random ensemble (TBRE) for a many-body bosonic theory is mapped to a problem of random polynomials on the unit interval. In this way one can understand the predominance of 0+ ground states, and analytic expressions can be derived for distributions ... More
Triangular random matrices and biorthogonal ensemblesApr 18 2014We study the singular values of certain triangular random matrices. When their elements are i.i.d. standard complex Gaussian random variables, the squares of the singular values form a biorthogonal ensemble, and with an appropriate change in the distribution ... More
A strong collapse increasing the geometric simplicial Lusternik-Schnirelmann categoryOct 26 2017In [3], after defining notions of LS category in the simplicial context, the authors show that the geometric simplicial LS category is non-decreasing under strong collapses. However, they do not give examples where it increases strictly, but they conjecture ... More
Ground Ring of Alpha-Symmetries and Sequence of RNS String TheoriesMay 29 2009Jun 03 2009We construct a sequence of nilpotent BRST charges in RNS superstring theory, based on new gauge symmetries on the worldsheet, found in this paper. These new local gauge symmetries originate from the global nonlinear space-time $\alpha$-symmetries, shown ... More
The Greek Public Debt Path: From Zero to InfinityDec 07 2012The aim of the present article is to treat the Greek public debt issue strictly as a curve fitting problem. Thus, based on Eurostat data and using the Mathematica technical computing software, an exponential function that best fits the data is determined ... More
Solutions in Bosonic String Field Theory and Higher Spin Algebras in AdSJul 22 2015Aug 04 2015We find a class of analytic solutions in open bosonic string field theory, parametrized by the chiral copy of higher spin algebra in $AdS_3$. The solutions are expressed in terms of the generating function for the products of Bell polynomials in derivatives ... More
Compositional Distributional Semantics with Compact Closed Categories and Frobenius AlgebrasMay 01 2015This thesis contributes to ongoing research related to the categorical compositional model for natural language of Coecke, Sadrzadeh and Clark in three ways: Firstly, I propose a concrete instantiation of the abstract framework based on Frobenius algebras ... More
Compositional Operators in Distributional SemanticsJan 21 2014This survey presents in some detail the main advances that have been recently taking place in Computational Linguistics towards the unification of the two prominent semantic paradigms: the compositional formal semantics view and the distributional models ... More
An algebra of power series arising in the intersection theory of moduli spaces of curves and in the enumeration of ramified coverings of the sphereMar 04 2004Apr 01 2004A bracket is a function that assigns a number to each monomial in variables \tau_0, \tau_1, ... We show that any bracket satisfying the string and the dilaton relations gives rise to a power series lying in the algebra A generated by the series \sum n^{n-1} ... More
A note on warpings of monoidal structuresOct 02 2015In \cite{LS14} the analogy between the Kleisli construction and the construction of "warping a skew monoidale category" in the sense of \cite{LS12} was outlined. In this note we present the same work in a slightly more formal way.
The Tannaka representation theorem for separable Frobenius functorsAug 08 2010A weak bialgebra is known to be a special case of a bialgebroid. In this paper we study the relationship of this fact with the Tannaka theory of bialgebroids as developed in [4]. We obtain a Tannaka representation theorem with respect to a separable Frobenius ... More
Asymptotic expansions of the inverse of the Beta distributionNov 11 2016Sep 21 2017In this work in progress, we study the asymptotic behaviour of the $p$-quantile of the Beta distribution, i.e. the quantity $q$ defined implicitly by $\int_0^q t^{a - 1} (1 - t)^{b - 1} \text{d} t = p B (a, b)$, as a function of the first parameter $a$. ... More
Construct Dynamic Graphs for Hand Gesture Recognition via Spatial-Temporal AttentionJul 20 2019We propose a Dynamic Graph-Based Spatial-Temporal Attention (DG-STA) method for hand gesture recognition. The key idea is to first construct a fully-connected graph from a hand skeleton, where the node features and edges are then automatically learned ... More
2nd Place Solution to the GQA Challenge 2019Jul 16 2019We present a simple method that achieves unexpectedly superior performance for Complex Reasoning involved Visual Question Answering. Our solution collects statistical features from high-frequency words of all the questions asked about an image and use ... More
Collaborative Multi-agent Learning for MR Knee Articular Cartilage SegmentationAug 13 2019The 3D morphology and quantitative assessment of knee articular cartilages (i.e., femoral, tibial, and patellar cartilage) in magnetic resonance (MR) imaging is of great importance for knee radiographic osteoarthritis (OA) diagnostic decision making. ... More
Lax monads, equipments and generalized multicategory theoryDec 13 2013Dec 16 2014Generalized multicategories, also called $T$-monoids, are well known class of mathematical structures, which include diverse set of examples. In this paper we construct a generalization of the adjunction between strict monoidal categories and multicategories, ... More
Strict \infty-groupoids are Grothendieck \infty-groupoidsDec 13 2012Apr 03 2013We show that there exists a canonical functor from the category of strict \infty-groupoids to the category of Grothendieck \infty-groupoids and that this functor is fully faithful. As a main ingredient, we prove that free strict \infty-groupoids on a ... More
Higher quasi-categories vs higher Rezk spacesJun 19 2012May 27 2015We introduce a notion of n-quasi-categories as fibrant objects of a model category structure on presheaves on Joyal's n-cell category \Theta_n. Our definition comes from an idea of Cisinski and Joyal. However, we show that this idea has to be slightly ... More
The groupoidal analogue Theta~ to Joyal's category Theta is a test categoryDec 20 2010Jul 27 2011We introduce the groupoidal analogue \tilde\Theta to Joyal's cell category \Theta and we prove that \tilde\Theta is a strict test category in the sense of Grothendieck. This implies that presheaves on \tilde\Theta model homotopy types in a canonical way. ... More
(Non)triviality of Pure Spinors and Exact Pure Spinor - RNS MapOct 26 2008Nov 21 2008All the BRST-invariant operators in pure spinor formalism in $d=10$ can be represented as BRST commutators, such as $V=\lbrace{Q_{brst}},{{\theta_{+}}\over{\lambda_{+}}}V\rbrace$ where $\lambda_{+}$ is the U(5) component of the pure spinor transforming ... More
Microstates free entropy and cost of equivalence relationsDec 29 1999We define an analog of Voiculescu's free entropy for n-tuples of unitaries (u_{1},...,u_{n}) in a tracial von Neumann algebra M, normalizing a unital diffuse abelian subalgebra B in M. Using this quantity, we define the free dimension \delta_{0}(u_{1},..,u_{n}\btw ... More
Prime Type III FactorsAug 18 2000We show that for each (0<\lambda <1), the free Araki-Woods factor of type III(_{\lambda}) cannot be written as a tensor product of two diffuse von Neumann algebras (i.e., is prime), and does not contain a Cartan subalgebra.
On multiplicative functions which are small on averageNov 11 2011Jun 17 2013Let $f$ be a completely multiplicative function that assumes values inside the unit disc. We show that if $\sum_{n<x} f(n) \ll x/(\log x)^A$, $x>2$, for some $A>2$, then either $f(p)$ is small on average or $f$ pretends to be $\mu(n)n^{it}$ for some $t$. ... More
Curvature transformationJul 22 2016A transformation based on mean curvature is introduced which morphs triangulated surfaces into round spheres.
Infrared signatures of high carrier densities induced in semiconducting poly(3-hexylthiophene) by fluorinated organosilane moleculesSep 01 2011We report on infrared (IR) absorption and dc electrical measurements of thin films of poly(3-hexylthiophene) (P3HT) that have been modified by a fluoroalkyl trichlorosilane (FTS). Spectra for FTS-treated films were compared to data for electrostatically-doped ... More
The Long-Term Dynamical Evolution of Planetary SystemsNov 26 2013This chapter concerns the long-term dynamical evolution of planetary systems from both theoretical and observational perspectives. We begin by discussing the planet-planet interactions that take place within our own Solar System. We then describe such ... More
Active correction of aperture discontinuities (ACAD) for space telescope pupils: a parametic analysisOct 10 2017As the performance of coronagraphs improves, the achievable contrast is more and more dependent of the shape of the pupil. The future generation of space and ground based coronagraphic instruments will have to achieve high contrast levels on on-axis and/or ... More
Groups of type L_2(q) acting on polytopesJun 26 2006We prove that if G is a string C-group of rank 4 and G is isomorphic to L_2(q) with q a prime power, then q must be 11 or 19. The polytopes arising are Grunbaum's 11-cell of type {3,5,3} for L_2(11) and Coxeter's 57-cell of type {5,3,5} for L_2(19), each ... More
Quantum determinant revisitedJun 17 2019Following [G] we define quantum determinants in certain quantum algebras, related to couples of compatible braidings. Also, we compare these quantum determinants with the highest elementary symmetric polynomials. Some properties of the quantum determinants ... More
Enumeration of almost polynomial rational functions with given critical valuesApr 29 2005Enumerating ramified coverings of the sphere with fixed ramification types is a well-known problem first considered by A. Hurwitz. Up to now, explicit solutions have been obtained only for some families of ramified coverings, for instant, those realized ... More
Constructions in public-key cryptography over matrix groupsJun 10 2005The purpose of the paper is to give new key agreement protocols (a multi-party extension of the protocol due to Anshel-Anshel-Goldfeld and a generalization of the Diffie-Hellman protocol from abelian to solvable groups) and a new homomorphic public-key ... More
Golden Elliptical Orbits in Newtonian GravitationNov 28 2017In spherical symmetry with radial coordinate $r$, classical Newtonian gravitation supports circular orbits and, for $-1/r$ and $r^2$ potentials only, closed elliptical orbits [1]. Various families of elliptical orbits can be thought of as arising from ... More
The fractal nature of an approximate prime counting functionNov 07 2016Prime number related fractal polygons and curves are derived by combining two different aspects. One is an approximation of the prime counting function build on an additive function. The other are prime number indexed basis entities taken from the discrete ... More
From Reflection Equation Algebra to Braided YangiansJun 26 2018In general, quantum matrix algebras are associated with a couple of compatible braidings. A particular example of such an algebra is the so-called Reflection Equation algebra. In this paper we analyse its specific properties, which distinguish it from ... More
Moduli of framed sheaves on projective surfacesJun 08 2009Sep 22 2009We show that there exists a fine moduli space for torsion-free sheaves on a projective surface, which have a "good framing" on a big and nef divisor. This moduli space is a quasi-projective scheme. This is accomplished by showing that such framed sheaves ... More
Noncommutative Geometry and dynamical models on U(u(2)) backgroundNov 25 2013Aug 19 2014In our previous publications we have introduced a differential calculus on the algebra $U(gl(m))$ based on a new form of the Leibniz rule which differs from that usually employed in Noncommutative Geometry. This differential calculus includes partial ... More
Integer part independent polynomial averages and applications along primesAug 07 2017Exploiting the equidistribution properties of polynomial sequences, following the methods developed by Leibman ("Pointwise Convergence of ergodic averages for polynomial sequences of translations on a nilmanifold. Ergodic Theory Dynam. Systems, 25 (2005) ... More
Steering Macro-Scale Network Community Structure by Micro-Scale FeaturesMar 17 2016Network science plays an increasingly important role to model complex data in many scientific disciplines. One notable feature of network organization is community structure, which refers to clusters of tightly interconnected nodes. A prominent problem ... More
The Threshold for Random k-SAT is 2^k ln2 - O(k)May 14 2003Sep 08 2003Let F be a random k-SAT formula on n variables, formed by selecting uniformly and independently m = rn out of all possible k-clauses. It is well-known that if r>2^k ln 2, then the formula F is unsatisfiable with probability that tends to 1 as n tends ... More
The Rotation of BulgesJan 14 2011Jan 19 2011I briefly review early and recent progress concerning the dynamical properties of bulges. I also show results from a study on the kinematics of bulges and disks in edge-on galaxies, where the bulge rotation curve is obtained with little contamination ... More
The Structural Parameters of Bulges, Bars and Discs in the Local UniverseAug 21 2007Image decomposition of galaxies is now routinely used to estimate the structural parameters of galactic components. In this work, I address questions on the reliability of this technique. In particular, do bars and AGN need to be taken into account to ... More
Generalized Yangians and their Poisson counterpartsFeb 10 2017By a generalized Yangian we mean a Yangian-like algebra of one of two classes. One of these classes consists of the so-called braided Yangians, introduced in our previous paper. The braided Yangians are in a sense similar to the reflection equation algebra. ... More
A fractional eigenvalue problem in $\mathbb{R}^N$Jun 18 2015We prove that a linear fractional operator with an asymptotically constant lower order term in the whole space admits eigenvalues.
Carleman estimates for singular parabolic equations with interior degeneracy and non smooth coefficientsJul 28 2015Nov 18 2015We establish Carleman estimates for singular/degenerate parabolic Dirichlet problems with degeneracy and singularity occurring in the interior of the spatial domain. Our results are completely new, since this situation is not covered by previous contributions ... More
Finite Inverse Categories as SignaturesJul 23 2017We define a simple dependent type theory and prove that its well-formed types correspond exactly to finite inverse categories.
Centers in Generalized Reflection Equation algebrasDec 17 2017Jun 26 2018In the Reflection Equation (RE) algebra associated with an involutive or Hecke symmetry $R$ the center is generated by elements ${\rm Tr}_R L^k$ (called the quantum power sums), where $L$ is the generating matrix of this algebra and ${\rm Tr}_R$ is the ... More
Design and properties of wave packet smoothness spacesApr 24 2019We introduce a family of quasi-Banach spaces - which we call wave packet smoothness spaces - that includes those function spaces which can be characterised by the sparsity of their expansions in Gabor frames, wave atoms, and many other frame constructions. ... More
Photo-enhanced metastable c-axis electrodynamics in stripe ordered cuprate La$_{1.885}$Ba$_{0.115}$CuO$_{4}$Jan 28 2019Quantum materials are amenable to non-equilibrium manipulation with light, enabling modification and control of macroscopic properties. Light-based augmentation of superconductivity is particularly intriguing. Copper-oxide superconductors exhibit complex ... More
Current oscillations in Vanadium Dioxide: evidence for electrically triggered percolation avalanchesSep 08 2011In this work, we experimentally and theoretically explore voltage controlled oscillations occurring in micro-beams of vanadium dioxide. These oscillations are a result of the reversible insulator to metal phase transition in vanadium dioxide. Examining ... More
Local moments and symmetry breaking in metallic PrMnSbOJun 02 2010We report a combined experimental and theoretical investigation of the layered antimonide PrMnSbO which is isostructural to the parent phase of the iron pnictide superconductors. We find linear resistivity near room temperature and Fermi liquid-like T^{2} ... More
A Mixed Value and Policy Iteration Method for Stochastic Control with Universally Measurable PoliciesAug 17 2013Dec 10 2014We consider stochastic control models with Borel spaces and universally measurable policies. For such models the standard policy iteration is known to have difficult measurability issues and cannot be carried out in general. We present a mixed value and ... More
Ghost-Matter Mixing and Feigenbaum Universality in String TheoryDec 12 2002Apr 23 2003Brane-like vertex operators, defining backgrounds with the ghost-matter mixing in NSR superstring theory, play an important role in a world-sheet formulation of D-branes and M theory, being creation operators for extended objects in the second quantized ... More
An infinite family of locally X graphs based on incidence geometriesNov 28 2018A graph ${\mathcal G}$ is locally X if the graphs induced on the neighbours of every vertex of ${\mathcal G}$ are isomorphic to the graph $X$. We prove that the infinite family of incidence graphs of the $r$-rank incidence geometries, $\Gamma(KG(n,k),r)$, ... More
Interpretable Matrix Completion: A Discrete Optimization ApproachDec 17 2018We consider the problem of matrix completion with side information on an $n\times m$ matrix. We formulate the problem exactly as a sparse regression problem of selecting features and show that it can be reformulated as a binary convex optimization problem. ... More
Neumann fractional $p-$Laplacian: eigenvalues and existence resultsApr 11 2019Apr 23 2019We develop some properties of the $p-$Neumann derivative for the fractional $p-$Laplacian in bounded domains with general $p>1$. In particular, we prove the existence of a diverging sequence of eigenvalues and we introduce the evolution problem associated ... More
Driving white dwarf metal pollution through unstable eccentric periodic orbitsAug 16 2019Planetary debris is observed in the atmospheres of over 1,000 white dwarfs, and two white dwarfs are now observed to contain orbiting minor planets. Exoasteroids and planetary core fragments achieve orbits close to the white dwarf through scattering with ... More
Towards a Characterization of Explainable SystemsJan 31 2019Building software-driven systems that are easily understood becomes a challenge, with their ever-increasing complexity and autonomy. Accordingly, recent research efforts strive to aid in designing explainable systems. Nevertheless, a common notion of ... More
Characterization of the equivalence of robustification and regularization in linear and matrix regressionNov 22 2014Feb 25 2017The notion of developing statistical methods in machine learning which are robust to adversarial perturbations in the underlying data has been the subject of increasing interest in recent years. A common feature of this work is that the adversarial robustification ... More
Quotients of a Universal Locally Projective Polytope of type {5,3,5}Jul 05 2003This article examines the universal polytope $\CP$ (of type $\{5,3,5\}$) whose facets are dodecahedra, and whose vertex figures are hemi-icosahedra. The polytope is proven to be finite, and the structure of its group is identified. This information is ... More
The structure of young embedded protostellar discsAug 04 2017Young protostellar discs provide the initial conditions for planet formation. The properties of these discs may be different from those of late-phase (T Tauri) discs due to continuing infall from the envelope and protostellar variability resulting from ... More
Accounting for Significance and Multicollinearity in Building Linear Regression ModelsFeb 08 2019We derive explicit Mixed Integer Optimization (MIO) constraints, as opposed to iteratively imposing them in a cutting plane framework, that impose significance and avoid multicollinearity for building linear regression models. In this way we extend and ... More
Bagging multiple comparisons from microarray dataMay 15 2007The problem of large-scale simultaneous hypothesis testing is re-visited. Bagging and subagging procedures are put forth with the purpose of improving the discovery power of the tests. The procedures are implemented in both simulated and real data. It ... More
Solitonic lattice and Yukawa forces in the rare earth orthoferrite TbFeO3Mar 22 2011The control of domains in ferroic devices lies at the heart of their potential for technological applications. Multiferroic materials offer another level of complexity as domains can be either or both of a ferroelectric and magnetic nature. Here we report ... More
Drinfeld-Sokolov reduction in quantum algebrasOct 04 2017Applying the method of the paper [CT], we perform a quantum version of the Drinfeld-Sokolov reduction in Reflection Equation algebras and braided Yangians, associated with involutive and Hecke symmetries of general forms. This reduction is based on the ... More
Permutations contained in transitive subgroupsMay 03 2016Feb 11 2017In the first paper in this series we estimated the probability that a random permutation $\pi\in\mathcal{S}_n$ has a fixed set of a given size. In this paper, we elaborate on the same method to estimate the probability that $\pi$ has $m$ disjoint fixed ... More
A row-sampling-based randomised finite element method for elliptic partial differential equationsMar 18 2019Jul 29 2019We consider a randomised implementation of the finite element method (FEM) for elliptic partial differential equations on high-dimensional models. This is motivated by applications where model predictions are essential for real-time process diagnostics. ... More
Numerical models for evolution of extreme wave groupsOct 23 2018Feb 19 2019The paper considers the application of two numerical models to simulate the evolution of steep breaking waves. The first one is a Lagrangian wave model based on equations of motion of an inviscid fluid in Lagrangian coordinates. A method for treating ... More
Two-Point String AmplitudesJun 14 2019We show that the two-point tree level amplitude in string theory in flat space is given by the standard free particle expression.
Equal sums in random sets and the concentration of divisorsAug 01 2019We study the extent to which divisors of a typical integer $n$ are concentrated. In particular, defining the Erd\H os-Hooley $\Delta$-function by $\Delta(n) := \max_t # \{d | n, \log d \in [t,t+1]\}$, we show that $\Delta(n) \geq (\log \log n)^{0.35332277\dots}$ ... More
Low Wind Effect on VLT/SPHERE : impact, mitigation strategy, and resultsJun 14 2018Jul 22 2018The low wind effect is a phenomenon disturbing the phase of the wavefront in the pupil of a large telescope obstructed by spiders, in the absence of wind. It can be explained by the radiative cooling of the spiders, creating air temperature inhomogeneities ... More
Similarities between structural distortions under pressure and chemical doping in superconducting BaFe2As2Dec 11 2009The discovery of a new family of high Tc materials, the iron arsenides (FeAs), has led to a resurgence of interest in superconductivity. Several important traits of these materials are now apparent, for example, layers of iron tetrahedrally coordinated ... More
Higher-order Accurate Spectral Density Estimation of Functional Time SeriesDec 07 2018Under the frequency domain framework for weakly dependent functional time series, a key element is the spectral density kernel which encapsulates the second-order dynamics of the process. We propose a class of spectral density kernel estimators based ... More
Exoplanets Beyond the Solar Neighbourhood: Galactic Tidal PerturbationsDec 17 2012The majority of Milky Way extrasolar planets likely reside within a few kpc of the Galactic centre. The Galactic tidal forces acting on planets scale inversely with radius in the Galaxy and so are much greater in the inner Galaxy than in the Solar neighbourhood. ... More
Planetary Orbital Equations in Externally-Perturbed Systems: Position and Velocity-Dependent ForcesOct 24 2012The increasing number and variety of extrasolar planets illustrates the importance of characterizing planetary perturbations. Planetary orbits are typically described by physically intuitive orbital elements. Here, we explicitly express the equations ... More
Computer-intensive rate estimation, diverging statistics and scanningOct 26 2007A general rate estimation method is proposed that is based on studying the in-sample evolution of appropriately chosen diverging/converging statistics. The proposed rate estimators are based on simple least squares arguments, and are shown to be accurate ... More
Stable marked point processesAug 03 2007In many contexts such as queuing theory, spatial statistics, geostatistics and meteorology, data are observed at irregular spatial positions. One model of this situation involves considering the observation points as generated by a Poisson process. Under ... More
Fixed-b Subsampling and Block Bootstrap: Improved Confidence Sets Based on P-value CalibrationApr 04 2012Subsampling and block-based bootstrap methods have been used in a wide range of inference problems for time series. To accommodate the dependence, these resampling methods involve a bandwidth parameter, such as subsampling window width and block size ... More
Imaging of anomalous internal reflections of hyperbolic phonon-polaritons in hexagonal boron nitrideApr 25 2016May 10 2016We use scanning near-field optical microscopy to study the response of hexagonal boron nitride nanocones at infrared frequencies, where this material behaves as a hyperbolic medium. The obtained images are dominated by a series of hot rings that occur ... More
Bindweeds or random walks in random environments on multiplexed trees and their asympoticsDec 15 2003We report on the asymptotic behaviour of a new model of random walk, we term the bindweed model, evolving in a random environment on an infinite multiplexed tree. The term \textit{multiplexed} means that the model can be viewed as a nearest neighbours ... More
Polarization degrees of freedom in photoinduced two-nucleon knockout from finite nucleiOct 01 1997The polarization degrees of freedom in photoinduced two-nucleon knockout from finite nuclei are studied. It is pointed out that they open good perspectives to study the dynamics of dinucleons in the medium in detail. The ($\gamma,pp$) and ($\gamma,pn$) ... More
The random pinning model with correlated disorder given by a renewal setSep 20 2017Dec 21 2018We investigate the effect of correlated disorder on the localization transition undergone by a renewal sequence with loop exponent $\alpha$ > 0, when the correlated sequence is given by another independent renewal set with loop exponent $\alpha$ > 0. ... More
A Software-Defined Channel Sounder for Industrial Environments with Fast Time VarianceMay 03 2018Novel industrial wireless applications require wideband, real-time channel characterization due to complex multipath propagation. Rapid machine motion leads to fast time variance of the channel's reflective behavior, which must be captured for radio channel ... More
Best Subset Selection via a Modern Optimization LensJul 11 2015In the last twenty-five years (1990-2014), algorithmic advances in integer optimization combined with hardware improvements have resulted in an astonishing 200 billion factor speedup in solving Mixed Integer Optimization (MIO) problems. We present a MIO ... More