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Coronoids, Patches and Generalised AltansSep 29 2015In this paper we revisit coronoids, in particular multiple coronoids. We consider a mathematical formalisation of the theory of coronoid hydrocarbons that is solely based on incidence between hexagons of the infinite hexagonal grid in the plane. In parallel, ... More

An algebraic approach to enumerating non-equivalent double traces in graphsNov 30 2015Recently designed biomolecular approaches to build single chain polypeptide polyhedra as molecular origami nanostructures have risen high interest in various double traces of the underlying graphs of these polyhedra. Double traces are walks that traverse ... More

On the Clar Number of Benzenoid GraphsSep 13 2017A Clar set of a benzenoid graph $B$ is a maximum set of independent alternating hexagons over all perfect matchings of $B$. The Clar number of $B$, denoted by ${\rm Cl}(B)$, is the number of hexagons in a Clar set for $B$. In this paper, we first prove ... More

Iterated altans and their propertiesApr 30 2015Recently a class of molecular graphs, called altans, became a focus of attention of several theoretical chemists and mathematicians. In this paper we study primary iterated altans and show, among other things, their connections with nanotubes and nanocaps. ... More

Characterization of circulant graphs having perfect state transferApr 11 2011In this paper we answer the question of when circulant quantum spin networks with nearest-neighbor couplings can give perfect state transfer. The network is described by a circulant graph $G$, which is characterized by its circulant adjacency matrix $A$. ... More

Which weighted circulant networks have perfect state transfer?Apr 11 2011The question of perfect state transfer existence in quantum spin networks based on weighted graphs has been recently presented by many authors. We give a simple condition for characterizing weighted circulant graphs allowing perfect state transfer in ... More

On absorption in semigroups and $n$-ary semigroupsApr 11 2015Jun 24 2015The notion of absorption was developed a few years ago by Barto and Kozik and immediately found many applications, particularly in topics related to the constraint satisfaction problem. We investigate the behavior of absorption in semigroups and n-ary ... More

An algebraic approach to enumerating non-equivalent double traces in graphsNov 30 2015Oct 29 2016Recently designed biomolecular approaches to build single chain polypeptide polyhedra as molecular origami nanostructures have risen high interest in various double traces of the underlying graphs of these polyhedra. Double traces are walks that traverse ... More

On the clique number of integral circulant graphsApr 06 2011The concept of gcd-graphs is introduced by Klotz and Sander, which arises as a generalization of unitary Cayley graphs. The gcd-graph $X_n (d_1,...,d_k)$ has vertices $0,1,...,n-1$, and two vertices $x$ and $y$ are adjacent iff $\gcd(x-y,n)\in D = \{d_1,d_2,...,d_k\}$. ... More

Homology of dendroidal setsSep 02 2015We define for every dendroidal set X a chain complex and show that this assignment determines a left Quillen functor. Then we define the homology groups $H_n(X)$ as the homology groups of this chain complex. This generalizes the homology of simplicial ... More

Splittable and unsplittable graphs and configurationsMar 17 2018We prove that there exist infinitely many splittable and also infinitely many unsplittable cyclic $(n_3)$ configurations. We also present a complete study of trivalent cyclic Haar graphs on at most 60 vertices with respect to splittability. Finally, we ... More

Point-ellipse and some other exotic configurationsMar 14 2019In this paper we introduce point-ellipse configurations and point-conic configurations. We study some of their basic properties and describe two interesting families of balanced point-ellipse, respectively point-conic $6$-configurations. The construction ... More

Sizes of Pentagonal Clusters in FullerenesMar 16 2017Stability and chemistry, both exohedral and endohedral, of fullerenes are critically dependent on the distribution of their obligatory 12 pentagonal faces. It is well known that there are infinitely many IPR-fullerenes and that the pentagons in these ... More

Models of Opinion Formation: Influence of Opinion LeadersApr 13 2007This paper studies the evolution of the distribution of opinions in a population of individuals in which there exist two distinct subgroups of highly-committed, well-connected opinion leaders endowed with a strong convincing power. Each individual, located ... More

Randomized Cellular AutomataFeb 23 2007We define and study a few properties of a class of random automata networks. While regular finite one-dimensional cellular automata are defined on periodic lattices, these automata networks, called randomized cellular automata, are defined on random directed ... More

High Redshift Supernovae: Cosmological ImplicationsFeb 11 2005We review the findings for the values of the cosmological parameters as derived from high-redshift SNIa measurements. The most recent results confirm the picture of a non-empty inflationary Universe that is consistent with a cosmological constant Omega_Lambda~0.7. ... More

Detecting Primordial StarsOct 08 2004We discuss the expected properties of the first stellar generations in the Universe. We find that it is possible to discern truly primordial populations from the next generation of stars by measuring the metallicity of high-z star forming objects. The ... More

On the existence of a variational principle for deterministic cellular automaton models of highway traffic flowMay 15 2000It is shown that a variety of deterministic cellular automaton models of highway traffic flow obey a variational principle which states that, for a given car density, the average car flow is a non-decreasing function of time. This result is established ... More

A Geometric Determination of the Distance to SN 1987A and the LMCSep 15 2003Using the definitive reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved our original analysis (Panagia et al. 1991) to derive a better determination of the distance ... More

SupernovaeMar 06 2000The properties of supernovae (SNe) are reviewed. It is shown that the observed characteristics of the morphological classes of SNe (types Ia, Ib/c, II) can be explained in terms of two basic explosion mechanisms, i.e. core collapse of massive stars and ... More

Ultraviolet Observations of SupernovaeApr 12 2007May 01 2007The motivations to make ultraviolet (UV) studies of supernovae (SNe) are reviewed and discussed in the light of the results obtained so far by means of IUE and HST observations. It appears that UV studies of SNe can, and do lead to fundamental results ... More

The Quest for Primordial Stellar Populations and the James Webb Space TelescopeSep 15 2003The NASA/ESA/CSA James Webb Space Telescope (JWST) will be the successor to the Hubble Space Telescope and may be launched as early as mid-2011. The key scientific goals for JWST are discovering and understanding the formation of the first stars and galaxies, ... More

Explicit expressions for real roots of a quartic equationFeb 23 2019This short article presents explicit expressions for roots of a quartic equation that has all four real roots. Although a general expression for quartic roots is available on Wikipedia, an optimized and slightly shorter expression for only real roots ... More

On the Reionization of the UniverseNov 11 2005I present first principle model calculations for the reionization of the Universe, which provide simple diagnostics to identify the reionization sources. Within this frame, I also discuss the results derived from the Hubble Ultra-Deep Field observations, ... More

SN 1987A: The Unusual Explosion of a Normal Type II SupernovaOct 11 2004I review the unwrapping story the SN 1987A explosion event, and the main discoveries associated with it. I will show that, although this supernova is somewhat peculiar, the study of SN 1987A has clarified quite a number of important aspects of the nature ... More

Primordial Stellar PopulationsSep 17 2002We review the expected properties of the first stellar generations in the Universe. In particular, we consider and discuss the diagnostics, based on the emission from associated HII regions, that permit one to discern bona fide primeval stellar generations ... More

The plasma emission model of RBS1774Dec 20 2010In the present paper we construct a self-consistent theory, interpreting the observational properties of RBS1774. It is well known that the distribution function of relativistic particles is one-dimensional at the pulsar surface. However, cyclotron instability ... More

On the emission polarization of RX J1856.5-3754Jan 21 2009The polarization properties of RX J1856.5-3754 are investigated, based on the plasma emission model presented in previous works. It is shown that if the emission of this source is generated by the synchrotron mechanism, the X-ray and the optical emission ... More

Eventually Number-Conserving Cellular AutomataOct 21 2004Feb 01 2005We present a preliminary study of a new class of two-input cellular automata called eventually number-conserving cellular automata characterized by the property of evolving after a finite number of time steps to states whose number of active sites remains ... More

Observational Constraints to the Evolution of Massive StarsFeb 28 2000We consider some aspects of the evolution of massive stars which can only be elucidated by means of "indirect" observations, i.e. measurements of the effects of massive stars on their environments. We discuss in detail the early evolution of massive stars ... More

An overview of type theoriesNov 04 2014Nov 06 2014Pure type systems arise as a generalisation of simply typed lambda calculus. The contemporary development of mathematics has renewed the interest in type theories, as they are not just the object of mere historical research, but have an active role in ... More

Unsolved Problems about SupernovaeMar 19 2009A number of unsolved problems and open questions about the nature and the properties of supernovae are identified and briefly discussed. Some suggestions and directions toward possible solutions are also considered.

Is it possible to control the spread of a globalized culture?Nov 17 2006We study a model describing the spread of a globalized culture in a population of individuals localized at the nodes of a social network. The influence of this globalized culture, assumed to be foreign to the local culture, is measured by a probability ... More

On the combinatorics of faces of trees and anodyne extensions of dendroidal setsJan 28 2018May 17 2018We discuss the combinatorics of faces of trees in the context of dendroidal sets and develop a systematic treatment of dendroidal anodyne extensions. As the main example and our motivation, we prove the pushout-product property for the stable model structure ... More

Noise cancellation effect in quantum systemsSep 03 2004We consider the time evolution of simple quantum systems under the influence of random fluctuations of the control parameters. We show that when the parameters fluctuate sufficiently fast, there is a cancellation effect of the noise. We propose that such ... More

Cellular automaton rules conserving the number of active sitesDec 12 1997Aug 27 1998This paper shows how to determine all the unidimensional two-state cellular automaton rules of a given number of inputs which conserve the number of active sites. These rules have to satisfy a necessary and sufficient condition. If the active sites are ... More

Generalized Deterministic Traffic RulesMay 14 1997We study a family of deterministic models for highway traffic flow which generalize cellular automaton rule 184. This family is parametrized by the speed limit $m$ and another parameter $k$ that represents a ``degree of aggressiveness'' in driving, strictly ... More

Synchrotron emission driven by the Cherenkov-drift instability in active galactic nucleiDec 10 2012In the present paper we study generation of the synchrotron emission by means of the feedback of Cherenkov drift waves on the particle distribution via the diffusion process. It is shown that despite the efficient synchrotron losses the excited Cherenkov ... More

Nonthermal emission model of isolated X-ray pulsar RX J0420.0-5022Apr 08 2013In the present paper an alternative theoretical interpretation to the generally assumed thermal emission models of the observed X-ray spectrum of isolated pulsar RX J0420.0-5022 is presented. It is well known that the distribution function of relativistic ... More

Nondeterministic automata: equivalence, bisimulations, and uniform relationsFeb 26 2011In this paper we study the equivalence of nondeterministic automata pairing the concept of a bisimulation with the recently introduced concept of a uniform relation. In this symbiosis, uniform relations serve as equivalence relations which relate states ... More

Prediction Capabilities of VLF/LF Emission as the Main Precursor of EarthquakeAug 16 2013Recent satellite and ground-based observations proved that in earthquake preparation period in the seismogenic area we have VLF/LF and ULF electromagnetic emissions. According to the opinion of the authors of the present paper this phenomenon is more ... More

On the mechanism of the pulsed high energy emission from the pulsar PSR B1509-58Dec 10 2012We investigate the high-energy (HE) ($<1$GeV) emission from the pulsar PSR B1509-58 and its relation to the radio emission in the 1.4GHz frequency band. The role of the quasi-linear diffusion in producing the pulsed HE radiation is investigated. We show ... More

Correlated random walks with a finite memory rangeMar 26 1999We study a family of correlated one-dimensional random walks with a finite memory range M.These walks are extensions of the Taylor's walk as investigated by Goldstein, which has a memory range equal to one. At each step, with a probability p, the random ... More

Modeling diffusion of innovations with probabilistic cellular automataMay 14 1997We present a family of one-dimensional cellular automata modeling the diffusion of an innovation in a population. Starting from simple deterministic rules, we construct models parameterized by the interaction range and exhibiting a second-order phase ... More

On the implementation of a deterministic secure coding protocol using polarization entangled photonsMar 26 2007Jul 21 2008We demonstrate a prototype-implementation of deterministic information encoding for quantum key distribution (QKD) following the ping-pong coding protocol [K. Bostroem, T. Felbinger, Phys. Rev. Lett. 89 (2002) 187902-1]. Due to the deterministic nature ... More

John Bell Across Space and TimeSep 01 2003This is a review of the book Quantum [Un]speakables: From Bell to Quantum Information. Reinhold A. Bertlmann and Anton Zeilinger (editors).

What is Bohmian MechanicsDec 02 2001Bohmian mechanics is a quantum theory with a clear ontology. To make clear what we mean by this, we shall proceed by recalling first what are the problems of quantum mechanics. We shall then briefly sketch the basics of Bohmian mechanics and indicate ... More

Convergence to equilibrium in a class of interacting particle systems evolving in discrete timeJan 20 2001We conjecture that for a wide class of interacting particle systems evolving in discrete time, namely conservative cellular automata with piecewise linear flow diagram, relaxation to the limit set follows the same power law at critical points. We further ... More

Learning the Structure for Structured SparsityMar 10 2015Sep 15 2015Structured sparsity has recently emerged in statistics, machine learning and signal processing as a promising paradigm for learning in high-dimensional settings. All existing methods for learning under the assumption of structured sparsity rely on prior ... More

Totalistic two-dimensional cellular automata exhibiting global periodic behaviorMar 29 1999We have determined families of two-dimensional deterministic totalistic cellular automaton rules whose stationary density of active sites exhibits a period two in time. Each family of deterministic rules is characterized by an ``average probabilistic ... More

On the possible mechanism to form the radio emission spectrum of the Crab pulsarMar 07 2014In the present paper a self-consistent theory, explaining shape of the observed phase-averaged radio spectrum in the frequency range from 100MHz to 10GHz is presented. The radio waves are assumed to be generated near the light cylinder through the cyclotron ... More

Number-conserving cellular automaton rulesMay 06 1999May 17 2000A necessary and sufficient condition for a one-dimensional q-state n-input cellular automaton rule to be number-conserving is established. Two different forms of simpler and more visual representations of these rules are given, and their flow diagrams ... More

Pre-Supernova Evolution of Massive StarsMar 14 2000We present the preliminary results of a detailed theoretical investigation on the hydrodynamical properties of Red Supergiant (RSG) stars at solar chemical composition and for stellar masses ranging from 10 to 20 M_sun. We find that the main parameter ... More

Cellular Automata Models for Diffusion of InnovationsApr 08 1997We propose a probabilistic cellular automata model for the spread of innovations, rumors, news, etc. in a social system. The local rule used in the model is outertotalistic, and the range of interaction can vary. When the range R of the rule increases, ... More

On high frequency Cherenkov-type radiation in pulsar magnetospheric electron-positron plasmaAug 13 2014Emission process of a charged particle propagating in a medium with a curved magnetic field is considered. This mechanism combines features of conventional Cherenkov and curvature emission. Thus, presence of a medium with the index of refraction larger ... More

Motion representation of one-dimensional cellular automaton rulesJan 24 2005Nov 06 2006Generalizing the motion representation we introduced for number-conserving rules, we give a systematic way to construct a generalized motion representation valid for non-conservative rules using the expression of the current, which appears in the discrete ... More

On the Classical Limit of Quantum MechanicsDec 02 2001Contrary to the widespread belief, the problem of the emergence of classical mechanics from quantum mechanics is still open. In spite of many results on the $\h \to 0$ asymptotics, it is not yet clear how to explain within standard quantum mechanics the ... More

On lower and upper bounds for Asian-type options: a unified approachSep 10 2013In the context of dealing with financial risk management problems it is desirable to have accurate bounds for option prices in situations when pricing formulae do not exist in the closed form. A unified approach for obtaining upper and lower bounds for ... More

Reality and the Role of the Wavefunction in Quantum TheoryJan 24 2011The most puzzling issue in the foundations of quantum mechanics is perhaps that of the status of the wave function of a system in a quantum universe. Is the wave function objective or subjective? Does it represent the physical state of the system or merely ... More

Martingales and first passage times of AR(1) sequencesDec 20 2007Using the martingale approach we find sufficient conditions for exponential boundedness of first passage times over a level for ergodic first order autoregressive sequences (AR(1)). Further, we prove a martingale identity to be used in obtaining explicit ... More

Smoothness of Wave Functions in Thermal EquilibriumSep 13 2005We consider the thermal equilibrium distribution at inverse temperature $\beta$, or canonical ensemble, of the wave function $\Psi$ of a quantum system. Since $L^2$ spaces contain more nondifferentiable than differentiable functions, and since the thermal ... More

Bisimulations for fuzzy automataFeb 26 2011May 05 2011Bisimulations have been widely used in many areas of computer science to model equivalence between various systems, and to reduce the number of states of these systems, whereas uniform fuzzy relations have recently been introduced as a means to model ... More

Star formation in the Local Group as seen by low-mass starsAug 28 2015We have undertaken a systematic study of pre-main sequence (PMS) stars spanning a wide range of masses (0.5 - 4 Msolar), metallicities (0.1 - 1 Zsolar) and ages (0.5 - 30 Myr). We have used the Hubble Space Telescope (HST) to identify and characterise ... More

Ultraviolet extinction properties of the 30 Dor Nebula and interpreting observations of starburst clustersApr 30 2019Recent investigation of the extinction law in 30 Dor and the Tarantula Nebula, at optical and near infrared (NIR) wavelengths, has revealed a ratio of total to selective extinction R_V=A_V/E(B-V) of about 4.5. This indicates a larger fraction of big grains ... More

Possibility of using of the measured frequency f instead of ω self-generated frequencyOct 26 2017Using f frequency instead of {\omega} frequency for earthquake magnitude computing is discussed.

New Possible Mechanisms of Thunderstorm Clouds PhysicsOct 30 2018Dec 07 2018The work provides possible mechanisms of physics of thunderstorm clouds. We tried to consider the problems of the hail clouds in a completely different view. The article is based on the latest scientific achievement of modern theoretical physics, chemistry, ... More

The extinction law inside the 30 Doradus nebulaAug 20 2014Sep 15 2014We have studied the interstellar extinction in a field of ~3' x 3' at the core of the 30 Doradus nebula, including the central R136 cluster, in the Large Magellanic Cloud. Observations at optical and near-infrared wavelengths, obtained with the WFC3 camera ... More

Electronegativity Scale from Path Integral FormulationMay 08 2003In the framework of the density functional theory a new electronegativity formulation via the Feynman-Kleinert path integral formalism in the markovian limit is proposed. The computation of the electronic density follows, in terms of partition function, ... More

The rate and the origin of type Ia supernovae in radiogalaxiesMar 12 2003An analysis of type Ia supernova (SNIa) events in early type galaxies from Evans et al (1989) database provides strong evidence that the rate of type Ia supernovae (SNe) in radio-loud galaxies is about 6 times higher than the rate measured in radio-quiet ... More

A Derivative-Free Trust Region Framework for Variational Data AssimilationMar 30 2014Feb 01 2015This study develops a hybrid ensemble-variational approach for solving data assimilation problems. The method, called TR-4D-EnKF, is based on a trust region framework and consists of three computational steps. First an ensemble of model runs is propagated ... More

Set theory and tableaux for teaching propositional logicJul 14 2015In this work we suggest the use of a set-theoretical interpretation of semantic tableaux for teaching propositional logic. If the student has previous notions of basic set theory, this approach to semantical tableaux can clarify her the way semantic trees ... More

Dendroidal sets as models for connective spectraMar 30 2012May 19 2014Dendroidal sets have been introduced as a combinatorial model for homotopy coherent operads. We introduce the notion of fully Kan dendroidal sets and show that there is a model structure on the category of dendroidal sets with fibrant objects given by ... More

Probing interstellar extinction near the 30 Doradus nebula with red giant starsNov 14 2013Dec 01 2013We have studied the interstellar extinction in a field of 3' x 3' located about 6' SW of 30 Doradus in the Large Magellanic Cloud (LMC). Hubble Space Telescope observations in the U, B, V, I and Halpha bands reveal patchy extinction in this field. The ... More

On the spectrum of the pulsed gamma-ray emission from 10MeV to 400GeV of the Crab pulsarJun 16 2012Aug 09 2012In the present paper a self-consistent theory, interpreting the VERITAS observations of the very high energy pulsed emission from the Crab pulsar is considered. The photon spectrum between 10MeV and 400GeV can be described by two power-law functions with ... More

On Conservative and Monotone One-dimensional Cellular Automata and Their Particle RepresentationJun 19 2003Jan 27 2004Number-conserving (or {\em conservative}) cellular automata have been used in several contexts, in particular traffic models, where it is natural to think about them as systems of interacting particles. In this article we consider several issues concerning ... More

Nature of phase transitions in a probabilistic cellular automaton with two absorbing statesFeb 23 2000Dec 12 2000We present a probabilistic cellular automaton with two absorbing states, which can be considered a natural extension of the Domany-Kinzel model. Despite its simplicity, it shows a very rich phase diagram, with two second-order and one first-order transition ... More

Analytical implementation of Roe solver for two-layer shallow water equations with accurate treatment for loss of hyperbolicityOct 26 2018Oct 30 2018A new implementation of the Roe scheme for solving two-layer shallow-water equations is presented in this paper. The proposed A-Roe scheme is based on the analytical solution to the characteristic quartic of the flux matrix, which is an efficient alternative ... More

Do you know the extinction in your young massive cluster?Sep 09 2015Up to ages of ~100 Myr, massive clusters are still swamped in large amounts of gas and dust, with considerable and uneven levels of extinction. At the same time, large grains (ices?) produced by type II supernovae profoundly alter the interstellar medium ... More

Photometric determination of the mass accretion rates of pre-main sequence stars. I. Method and application to the SN1987A fieldFeb 25 2010We have developed and successfully tested a new self-consistent method to reliably identify pre-main sequence (PMS) objects actively undergoing mass accretion in a resolved stellar population, regardless of their age. The method does not require spectroscopy ... More

The Initial Conditions to Star Formation: Low Mass Stars at Low MetallicityOct 06 2004We have measured the present accretion rate of roughly 800 low-mass (~1-1.4 Mo) pre-Main Sequence stars in the field of SN 1987A in the Large Magellanic Cloud. The stars with statistically significant Balmer continuum and Halpha excesses are measured ... More

Quantum Motion on Shape Space and the Gauge Dependent Emergence of Dynamics and Probability in Absolute Space and TimeAug 21 2018Relational formulations of classical mechanics and gravity have been developed by Julian Barbour and collaborators. Crucial to these formulations is the notion of shape space. We indicate here that the metric structure of shape space allows one to straightforwardly ... More

Is the Hypothesis About a Low Entropy Initial State of the Universe Necessary for Explaining the Arrow of Time?Feb 09 2016Jul 06 2016According to statistical mechanics, micro-states of an isolated physical system (say, a gas in a box) at time $t_0$ in a given macro-state of less-than-maximal entropy typically evolve in such a way that the entropy at time $t$ increases with $|t-t_0|$ ... More

On the Weak Measurement of Velocity in Bohmian MechanicsAug 25 2008In a recent article (New Journal of Physics 9, 165, 2007), Wiseman has proposed the use of so-called weak measurements for the determination of the velocity of a quantum particle at a given position, and has shown that according to quantum mechanics the ... More

Quantum Equilibrium and the Origin of Absolute UncertaintyAug 06 2003The quantum formalism is a ``measurement'' formalism--a phenomenological formalism describing certain macroscopic regularities. We argue that it can be regarded, and best be understood, as arising from Bohmian mechanics, which is what emerges from Schr\"odinger's ... More

Quantum Equilibrium and the Role of Operators as Observables in Quantum TheoryAug 06 2003Aug 06 2003Bohmian mechnaics is the most naively obvious embedding imaginable of Schr\"odingers's equation into a completely coherent physical theory. It describes a world in which particles move in a highly non-Newtonian sort of way, one which may at first appear ... More

Bohmian Mechanics and the Meaning of the Wave FunctionDec 29 1995We outline how Bohmian mechanics works: how it deals with various issues in the foundations of quantum mechanics and how it is related to the usual quantum formalism. We then turn to some objections to Bohmian mechanics, for example the fact that in Bohmian ... More

A Nonlinear Orthogonal Non-Negative Matrix Factorization Approach to Subspace ClusteringSep 29 2017A recent theoretical analysis shows the equivalence between non-negative matrix factorization (NMF) and spectral clustering based approach to subspace clustering. As NMF and many of its variants are essentially linear, we introduce a nonlinear NMF with ... More

Bitcoin Volatility Forecasting with a Glimpse into Buy and Sell OrdersFeb 12 2018Feb 06 2019In this paper, we study the ability to make the short-term prediction of the exchange price fluctuations towards the United States dollar for the Bitcoin market. We use the data of realized volatility collected from one of the largest Bitcoin digital ... More

On moments of Pitman estimators: the case of fractional Brownian MotionJun 05 2014In some non-regular statistical estimation problems, the limiting likelihood processes are functionals of fractional Brownian motion (fBm) with Hurst's parameter H; 0 < H <=? 1. In this paper we present several analytical and numerical results on the ... More

An Ensemble Kalman Filter Implementation Based on Modified Cholesky Decomposition for Inverse Covariance Matrix EstimationMay 28 2016This paper develops an efficient implementation of the ensemble Kalman filter based on a modified Cholesky decomposition for inverse covariance matrix estimation. This implementation is named EnKF-MC. Background errors corresponding to distant model components ... More

Numerical inverse Laplace transform for convection-diffusion equationsJan 09 2018Sep 06 2018In this paper a novel contour integral method is proposed for linear convection-diffusion equations. The method is based on the inversion of the Laplace transform and makes use of a contour given by an elliptic arc joined symmetrically to two half-lines. ... More

Ensemble Kalman Filter Implementations Based on Covariance Matrix EstimationFeb 01 2015This paper develops efficient ensemble Kalman filter (EnKF) implementations based on shrinkage covariance estimation. The forecast ensemble members at each step are used to estimate the background error covariance matrix via the Rao-Blackwell Ledoit and ... More

On the upper and lower estimates of norms in variable exponent spacesNov 13 2014In the present paper we investigate some geometrical properties of the norms in Banach function spaces. Particularly there is shown that if exponent $1/p(\cdot)$ belongs to $BLO^{1/\log}$ then for the norm of corresponding variable exponent Lebesgue space ... More

Weak Values from Displacement Currents in Multiterminal Electron DevicesAug 02 2015Jun 02 2016Weak values allow the measurement of observables associated with noncommuting operators. Up to now, position-momentum weak values have been mainly developed for (relativistic) photons. In this Letter, a proposal for the measurement of such weak values ... More

Clues to the star formation in NGC 346 across time and spaceJun 28 2011We have studied the properties of the stellar populations in the field of the NGC 346 cluster in the Small Magellanic Cloud, using the results of a novel self-consistent method that provides a reliable identification of pre-main sequence (PMS) objects ... More

Type Ia Supernova Rates Near and FarMar 15 2007(ABRIDGED) Recently, three important observational results were established: (a) The evolution of the SNIa rate with redshift show that the rate rises up to z~0.8, when the Universe was 6.5 Gyr old, and decreases afterward. (b) The rate of supernova explosions ... More

Low-Mass Pre-Main Sequence Stars in the Large Magellanic Cloud - III: Accretion Rates from HST-WFPC2 ObservationsFeb 19 2004Feb 21 2004We have measured the present accretion rate of roughly 800 low-mass (~1-1.4 Mo) pre-Main Sequence stars in the field of Supernova 1987A in the Large Magellanic Cloud (LMC, Z~0.3 Zo). It is the first time that this fundamental parameter for star formation ... More

Bohmian Trajectories as the Foundation of Quantum MechanicsDec 14 2009Bohmian trajectories have been used for various purposes, including the numerical simulation of the time-dependent Schroedinger equation and the visualization of time-dependent wave functions. We review the purpose they were invented for: to serve as ... More

The Quantum Formalism and the GRW FormalismOct 03 2007Aug 28 2012The Ghirardi-Rimini-Weber (GRW) theory of spontaneous wave function collapse is known to provide a quantum theory without observers, in fact two different ones by using either the matter density ontology (GRWm) or the flash ontology (GRWf). Both theories ... More

Robustness of non-abelian holonomic quantum gates against parametric noiseDec 12 2003Aug 06 2004We present a numerical study of the robustness of a specific class of non-abelian holonomic quantum gates . We take into account the parametric noise due to stochastic fluctuations of the control fields which drive the time-dependent Hamiltonian along ... More