Miracle-dz/UniFAR-FTUs huggingface dataset:
Application of the finite difference time domain algorithm to quasi‐static field analysis

In this paper, the use of the standard finite difference time domain (FDTD) algorithm is extended to quasi‐static electromagnetic field problems. While straightforward application of the standard FDTD algorithm at very low frequencies leads to excessively long simulation times, we show that for linear structures this problem can be circumvented by using a ramp excitation function. The use of appropriate absorbing boundary conditions such as Berenger's perfectly matched layer is also shown to be necessary. By combining two plane waves in opposite directions, a uniform electric or magnetic field can be created so that the electric and magnetic field solutions are decoupled, as required in quasi‐static analysis. Calculations of the induced fields and currents in a human model exposed to power line frequency fields provide a realistic example of an application of this novel FDTD technique.
Transition from Gaussian to Non-Gaussian Velocity Distribution Functions in a Vibrated Granular Bed

Probability distribution functions (PDFs) of velocity fluctuations in a 2-d vibrated bed of granular materials are studied numerically using a viscoelastic particle model. The PDF of horizontal velocity is closely related to the packing density ( P . D .) of particles. At low P . D . , particles move randomly and their motions are uncorrelated, and the distribution is Gaussian. At high P . D . , particle motions are correlated, and the PDF becomes a non-Gaussian distribution with an exponential tail. The flatness factor of velocity fluctuations is calculated as a function of P . D . , and continuous transition from Gaussian to non-Gaussian distribution is observed.
PKS 2149−306 and CXOCDFS J033225.3−274219: Two AGNs with Unusual Spectra Possibly Blueshifted?

PKS 2149-306 and CXOCDFS J033225.3-274219 each exhibit several emission lines in their optical spectra from which their redshifts have been determined. However, an ASCA spectrum of the first object has detected an emission line at 5 keV observed wavelength, and the Chandra ACIS-I spectrum of the second object shows a very strong emission feature at the observed wavelength of 6.2 keV. The two lines cannot be identified with any known search line on the basis of their redshift values without invoking extremely large outflow bulk velocities of 0.6c-0.75c. Such high bulk velocities are practically unheard of in any other observations of extragalactic objects. We show here that all the lines in both the optical and X-ray spectra of the two objects can be identified with lines at longer wavelengths that are blueshifted. We propose a scenario in which the spectrum is blueshifted due to net apparent motion toward the observer, resulting from an ejection.
Evaluating the effectiveness of smoothing algorithms in the absence of ground reference measurements

Time series of vegetation indices like NDVI are used in numerous applications ranging from ecology to climatology and agriculture. Often, these time series have to be filtered before application. The smoothing removes noise introduced by undetected clouds and poor atmospheric conditions. Ground reference measurements are usually difficult to obtain due to the medium/coarse resolution of the imagery. Hence, new filter algorithms are typically only (visually) assessed against the existing smoother. The present work aims to propose a range of quality indicators that could be useful to qualify filter performance in the absence of ground-based reference measurements. The indicators comprise (i) plausibility checks, (ii) distance metrics and (iii) geostatistical measures derived from variogram analysis. The quality measures can be readily derived from any imagery. For illustration, a large SPOT VGT dataset (1999–2008) covering South America at 1 km spatial resolution was filtered using the Whittaker smoother.
On the Semantics of the Subset Principle

Virtually all generative accounts of language development assume that syntactic acquisition is guided by a learnability constraint called the Subset Principle (SP). In essence, SP forces learners to initially select the value of a parameter that generates the smallest possible language. Recent work on the acquisition of semantics suggests that there also are semantic subset problems; therefore, one needs a Semantic Subset Principle (SSP) to solve these problems. This article shows that (a) to the extent that semantic subset problems exist, the SSP is not the correct solution to them and (b) that semantic subset problems most likely do not exist in the first place. These conclusions have important implications for theories of the acquisition of semantic knowledge and for the study of language acquisition more generally. First, they provide a basis for delimiting the class of problems that theories of the acquisition of semantics ought to be responsible for. Second, these conclusions underscore the fact that data from empirical investigations of child language can be brought to bear on the formulation of linguistic theory.
Control of point defects and space charge in electroluminescent ZnS:Mn thin films

The mechanisms leading to improved brightness, efficiency, and stability of alternating-current thin-film electroluminescent (ACTFEL) ZnS:Mn phosphors have been studied. Previously we have shown that ex situ codoping of the sputter deposited ZnS:Mn active layer with K and Cl results in a 53% improvement in brightness, a 62% improvement in efficiency, and better 100 h accelerated aging stability. In this work, we demonstrate that these improvements result from a 75% increase in excitation efficiency for conduction electrons, combined with a small decrease in both light outcoupling and nonradiative recombination. Electrical properties data were used to determine that there is a reduced amount of static space charge in the codoped films, resulting in a larger average field, increased excitation efficiency, and increased charge multiplication. The reduced space charge is attributed to the addition of charge compensating zinc vacancy–chlorine complexes and isolated chlorine point defects, which are acceptor an.
Modulation of tropical convection by breaking Rossby waves

This work discusses observations of both the convective‐inhibiting and convective‐promoting properties associated with Rossby waves that break in the extratropics and extend into the tropics. Two tropical drought periods—times of reduced tropical cloudiness and rainfall—were observed during mid to late November 2005 over a wide area of north‐west Australia, with an observed eruption of a nearby synoptic tropical cloud band in between times. Both convective inhibition and promotion appear to be linked to the descent of dry upper tropospheric air within a series of tropopause folds; convective inhibition was observed within the dry pool itself, whilst convective promotion was observed on the high moisture gradient at the leading edge of an advancing dry slot. A range of satellite images, surface rain gauges, radiosonde and ozonesonde data are used in conjunction with back trajectories and European Centre for Medium‐Range Weather Forecasts (ECMWF) analysis fields to investigate the origins and dynamics associated with these convective events, showing each to be ultimately linked to breaking Rossby wave activity on the southern subtropical jet. Together, these observations support a growing number of studies linking midlatitude tropopause‐level dynamics with the modulation of tropical deep convection, an influence that is poorly characterized when considering the climatology of tropical cloudiness and rainfall. Copyright © 2008 Royal Meteorological Society
PLANE STRAIN AND AXISYMMETRIC SPALLATION OF GRADED COATINGS UNDER THERMAL LOADING

In this study the failure mechanics of thermal barrier coatings under thermally induced in-plane compression is considered. The layered medium studied is assumed to consist of a substrate (the main structural component), a bond coat (the oxygen diffusion barrier), a thin layer of thermally grown oxide that develops during operation, and a homogeneous ceramic or graded metal/ceramic top coat (the primary heat shield). After presenting some results from the plane strain solution, the axisymmetric problem is considered in some detail. Noting that for the geometry and loading studied, namely a layered medium with an interface crack that is subjected to in-plane compression, the small deformation theory would give only a trivial result, and in order to assess the limitation of the plate theory that is often used to study such instability problems, a finite deformation continuum theory is used to solve the instability and the postbuckling problems. A nonlinear finite element method incorporating special enriched and transition elements is used to analyze the problem. The primary objective of the study is the investigation of the effect of property grading parameters, kinematic nonlinearity, plate approximation, and component curvature on the crack-tip stress intensity factors, the strain energy release rate, and the crack-opening displacements.
Pseudospectra, MUSIC, and dynamic wavelet neural network for damage detection of highrise buildings

A non‐parametric system identification‐based model is presented for damage detection of highrise building structures subjected to seismic excitations using the dynamic fuzzy wavelet neural network (WNN) model developed by the authors. The model does not require complete measurements of the dynamic responses of the whole structure. A large structure is divided into a series of sub‐structures around a few pre‐selected floors where sensors are placed and measurements are made. The new model balances the global and local influences of the training data and incorporates the imprecision existing in the sensor data effectively, thus resulting in fast training convergence and high accuracy. A new damage evaluation method is proposed based on a power density spectrum method, called pseudospectrum. The multiple signal classification (MUSIC) method is employed to compute the pseudospectrum from the structural response time series. The methodology is validated using the data obtained for a 38‐storey concrete test model. The results demonstrate the effectiveness of the WNN model together with the pseudospectrum method for damage detection of highrise buildings based on a small amount of sensed data. Copyright © 2007 John Wiley & Sons, Ltd.
134340 Pluto: nine years of CCD observations

Aims. The purpose of this article is to present the new accurate astrometric CCD positions of Pluto, now designated as the minor planet 134340 Pluto and member of the Trans-Neptunian population. These positions were obtained from 1108 frames taken during 49 nights. The observations were distributed in 17 continuous missions between the years of 1995 and 2004. Methods. The USNO-A2.0 star catalog, locally corrected by UCAC2 catalog, was used for the astrometric calibration. All positions were compared with those calculated by the PLU017 ephemeris. Results. In this work precise positions of 134340 Pluto are presented. The residues, observed minus calculated positions, have mean and standard deviation smaller than 0. �� 05, in the right ascension and declination coordinates’ directions.
Lattice Boltzmann Analysis of Fluid-Structure Interaction with Moving Boundaries

This work is concerned with the modelling of the interaction of fluid flow with flexibly supported rigid bodies. The fluid flow is modelled by Lattice-Boltzmann Method, coupled to a set of ordinary differential equations describing the dynamics of the solid body in terms its elastic and damping properties. The time discretization of the body dynamics is performed via the Time Discontinuous Galerkin Method. Several numerical examples are presented and highlight the robustness and efficiency of the proposed methodology, by means of comparisons with previously published results. The examples show that the present fluid-structure method is able to capture vortex- induced oscillations of flexibly-supported rigid body.
A nonsmooth version of the univariate optimization algorithm for locating the nearest extremum (locating extremum in nonsmooth univariate optimization)

An algorithm for univariate optimization using a linear lower bounding function is extended to a nonsmooth case by using the generalized gradient instead of the derivative. A convergence theorem is proved under the condition of semismoothness. This approach gives a globally superlinear convergence of algorithm, which is a generalized Newton-type method.
Invertibility of Nonlinear Control Systems

This paper gives necessary and sufficient conditions for the invertibility of nonlinear control systems of the form $\dot x = A(x) + uB(x)$; $y = c(x)$, where the state space is a real analytic manifold. For invertible systems we construct nonlinear inverse systems. These results are used to study the question of functional controllability for nonlinear systems. The class of real analytic functions which can appear as outputs of a given nonlinear system is described, and a prefilter is constructed to generate the required control.
Gravitational Collapse and Fragmentation of Molecular Cloud Cores with GADGET-2

The collapse and fragmentation of molecular cloud cores is examined numerically with unprecedentedly high spatial resolutions, using the publicly released code GADGET-2. As templates for the model clouds we use the "standard isothermal test case" in the variant calculated by Burkert & Bodenheimer in 1993 and the centrally condensed, Gaussian cloud advanced by Boss in 1991. A barotropic equation of state is used to mimic the nonisothermal collapse. We investigate both the sensitivity of fragmentation to thermal retardation and the level of resolution needed by smoothed particle hydrodynamics (SPH) to achieve convergence to existing Jeans-resolved, finite-difference (FD) calculations. We find that working with 0.6-1.2 million particles, acceptably good convergence is achieved for the standard test model. In contrast, convergent results for the Gaussian-cloud model are achieved using from 5 to 10 million particles. If the isothermal collapse is prolonged to unrealistically high densities, the outcome of collapse for the Gaussian cloud is a central adiabatic core surrounded by dense trailing spiral arms, which in turn may fragment in the late evolution. If, on the other hand, the barotropic equation of state is adjusted to mimic the rise of temperature predicted by radiative transfer calculations, the outcome of collapse is a protostellar binary core. At least, during the early phases of collapse leading to formation of the first protostellar core, thermal retardation not only favors fragmentation but also results in an increased number of fragments, for the Gaussian cloud.
A Bipolar Outflow of the M-Type Giant IRC −10414 Traced by HO Maser Emission

We report on results of five-epoch VLBI observations of H2O maser emission in the M-type star IRC � 10414, carried out with the VLBI Exploration of Radio Astrometry (VERA). The maser distribution extends over an area of 70 mas � 260 mas and exhibits a bipolar structure. The relative proper motions of 17 maser features were measured during the monitoring observations spanning nine months. The distance to IRC � 10414 was re-estimated on the basis of the statistical treatment of parallax and the model-fitting method, yielding D = 3.1 ˙ 0.4 kpc and D = 2.0 ˙ 0.2 kpc, respectively. The estimated distance, D = 2–3 kpc, is much larger than that previously adopted. The stellar luminosity of IRC � 10414 is also re-estimated to be L� � 9 � 10 4 (D=2 kpc) 2 Lˇ, much brighter by a factor of 10–20 than previously adopted (L� � 10000 Lˇ). The maser motions exhibit not only a spherically expanding flow with a velocity of � 10 (D=2 kpc) km s � 1 , but also a faster bipolar outflow with a major axis in the north–south direction and at a small inclination angle with respect to the celestial sphere. These characteristics of the star and the
A generalization of Brayton-Moser's mixed potential function

In this paper we give algorithms for constructing the Brayton-Moser's mixed potential function for a class of nonlinear reciprocal RLC networks, and we state necessary conditions for their existence. We have attempted to find the largest possible class of networks for which such a scalar function of state variables consisting of capacitor voltages and inductor currents can be constructed explicitly. Our results are applicable to a certain subclass of complete networks. From a mathematical point of view, we show that the corresponding network equations belong to the class of index I systems.
Convergence of approximation schemes for fully nonlinear second order equations

The convergence of a wide class of approximation schemes to the viscosity solution of fully nonlinear second-order elliptic or parabolic, possibly degenerate, partial differential equations is studied. It is proved that any monotone, stable, and consistent scheme converges (to the correct solution), provided that there exists a comparison principle for the limiting equation. Several examples are given where the result applies. <<ETX>>
The family of all recursively enumerable classes of finite sets

We prove that if P(x) is any first-order arithmetical predicate which enumerates the family Fin of all r.e. classes of finite sets, then P(x) must reside in a level of the Kleene hierarchy at least as high as II3 -O. (It is more easily established that some of the predicates P(x) which enumerate Fin do lie in HO -EO. )
Discontinuous Galerkin method based on peridynamic theory for linear elasticity

Modeling of discontinuities (shock waves, crack surfaces, etc.) in solid mechanics is one of the major research areas in modeling the mechanical behavior of materials. Among the numerical methods, the discontinuous Galerkin method (DGM) poses some advantages in solving these problems. In this study, a novel formulation for DGM is derived for elastostatics based on the peridynamic theory. Derivation of the proposed formulation is presented. Numerical analyses are performed for different problems, and the numerical results are compared to that of the known exact solutions of the problems. The proposed weak formulation is stable and coercive. Peridynamic discontinuous Galerkin formulation is found to be robust and successful in modeling elastostatic problems. Copyright © 2011 John Wiley & Sons, Ltd.
A general form for recursive adaptive algorithms leading to an exact recursive CMA

A new derivation of recursive adaptive algorithms which leads to a general formulation of the updating equation is provided. After showing that the classical recursive least square (RLS) algorithm is a special case of this approach, it is shown that with some ad hoc approximations this formulation can be applied to the constant modulus (CM) criterion. The algorithm obtained is simulated in the mobile radio context and its performances are compared to those of other classical or more recent algorithms with a constant modulus criterion, showing a significant improvement in convergence rate and residual error. <<ETX>>
G1 fitting with clothoids

A new algorithm for the solution to the problem of Hermite G1 interpolation with a clothoid curve is herein proposed, that is, a clothoid that interpolates two given points in a plane with assigned unit tangent vectors. The interpolation problem is formulated as a system of three nonlinear equations with multiple solutions, which is difficult to solve even numerically. In this work the solution of this system is reduced to the computation of the zeros of only one single nonlinear function in one variable. The location of the relevant zero is tackled analytically: it is provided the interval containing the zero where the solution is proved to exist and to be unique. A simple guess function allows to find that zero with very few iterations in all of the possible instances. Computing clothoid curves calls for evaluating Fresnel‐related integrals, asymptotic expansions near critical values are herein conceived to avoid loss of precision. This is particularly important when the solution of the interpolation problem is close to a straight line or an arc of circle. The present algorithm is shown to be simple and compact. The comparison with literature algorithms proves that the present algorithm converges more quickly and accuracy is conserved in all of the possible instances, whereas other algorithms have a loss of accuracy near the transition zones. Copyright © 2014 John Wiley & Sons, Ltd.
Blind Source Separation of Convolutive Mixtures by Using Time-Delayed Statistics and Exact Diagonalization

The convolutive blind source separation (BSS) problem has been received much more attentions in recent years. This paper investigates a convolutive BSS algorithm via employing the time-delayed second-order statistics information and exact diagonalization without any a priori knowledge on the mixtures. This decorrelated second-order statistics and its multi-sample delayed copies, which form two positive-definite symmetry matrices, are obtained from whitened mixtures. By using a set of transforms such as Cholesky decomposition and singular value decomposition (SVD) to these two matrices, a unitary matrix is obtained and utilized to diagonalize them exactly. It attributes the estimates of source signals to this matrix. The similarity between the estimated and original signals is quantified by calculating their correlation coefficients (CC). For the mixtures of speech and noise, ItakuraSaito distance (ISD) is applied to measure the intelligibility of estimated speech signals. Better performance of the investigated algorithm is demonstrated in experimental results compared with the previous algorithm.
Reynolds number influence on preferential concentration of heavy particles in turbulent flows

We present a study of the preferential concentration and clustering in homogeneous and isotropic turbulence. Using Voronoï diagrams, we have formerly quantified preferential concentration as a function of the Stokes number in moderate turbulence conditions up to Reynolds number based on Taylor microscale of the order of Rλ ∼ 120. Using an active grid recently implemented in our windtunnel, we investigate in the present study, the effect of Reynolds number on particles clustering, in the range Rλ ∼ 200 – 400.
Flow in alluvial-river curves

Uniform flow in curved, wide, erodible-bed channels is formulated on the basis of the conservation of flux of moment-of-momentum, to obtain relations for the vertical distributions of radial-plane velocity and radial shear stress. The expression for the radial stress exerted on the bed is utilized in a force-equilibrium analysis of the moving bed layer to obtain relations for the average transverse slope of the bed and for the radial bed profile. The reduction of primary bed shear stress due to the net radial transport of streamwise momentum toward the outer (concave) bank is then calculated, by introducing the derived expressions for the velocity components into the momentum equation for the primary-flow direction. It is found that the stress reductions in deep, narrow channels can exceed 50%. Bed profiles and velocity distributions measured in natural and laboratory streams are found to be in good conformity with those calculated from this moment-based theory.