Miracle-dz/UniFAR-FTUs huggingface dataset:
Predictive control for systems with time delay

Abstract A Smith predictor has been known as an effective controller to overcome a dead time. If the plant, however, is unstable, the closed-loop system cannot be stabilized with a Smith predictor. In order to stabilize an unstable plant with time delay, we propose a predictive control which is composed of an observer, a predictor and a controller. We refer to the realization of the predictor, and indicate an available type of model for it. In addition, we suggest the possibility that predictive control with a stable approximate model may be applied to an astatic plant.
Heat transfer in crystalline clathrate hydrates at low temperatures

The experimental results on the thermal conductivity κ(T) of crystalline Xe, CH4, and THF clathrate hydrates are analyzed. In a wide region of temperatures above 2K, κ(T) exhibits a behavior typical of disordered solids, which depends weakly on their chemical composition, crystalline structure, and microstructure. The results are discussed in the context of phenomenological models of phonon scattering by local modes. It is found that the Xe clathrate has a feature unusual for glasses, namely, κ(T) decreases almost two-fold as the temperature increases from 50 to 100K. The behavior of κ(T) is presumably determined mainly by the strong phonon scattering on water molecules.
CASINO: A new monte carlo code in C language for electron beam interactions—part II: Tabulated values of the mott cross section

This paper presents routines to compute the Mott cross section used in the CASINO program (Monte CArlo SImulation of electroN trajectory in sOlid). The routines used tabulated values of the Mott cross section computed in the work of Czyzewski et al. (1990). The cross section is available over the range 0.02 to 30 keV and for the first 94 elements of the Periodic Table. The routines are written in C language and use a binary file to interpolate the cross section. The first routine computes the total Mott cross sections; the second calculates the polar angle of collision. Backscattered coefficients computed using different cross section are compared for C, Al, Ag, and Au. The Rutherford (1911) cross section and the available empirical equations (Browning et al. 1994, Gauvin and Drouin 1993) are compared to tabulated values of Mott. Also, the energy distribution of backscattered electrons is shown for Al and Au at 10 keV. Finally, the relative computation times for the different Mott cross sections are compared. It was found that tabulated Mott cross sections are more accurate and faster than any empirical Mott cross sections. The tabulated Mott cross sections are even faster than simple Rutherford cross sections.
p-n junctions on Ga-face GaN grown by NH3 molecular beam epitaxy with low ideality factors and low reverse currents

A comprehensive analysis of forward and reverse current of Ga-face GaN p-n junctions grown by NH3 molecular beam epitaxy (NH3-MBE) on metal organic chemical vapor deposition (MOCVD) GaN:Fe on sapphire is presented. NH3-MBE has a great potential for growing low leakage vertical devices due to its nitrogen-rich growth. Diodes with the lowest n-doping of n∼3.5×1017 cm−3 exhibit an extremely low reverse current of 2.6×10−7 A/cm2 at −40 V and an ideality factor of 1.3, which is lower than the state-of-the-art Ga-face p-n junctions grown on sapphire by MOCVD. An explanation for the difficulty for observing low ideality factors in GaN is presented.
Using hyperarticulation to quantify interaction between discourse functions.

Social factors are known to affect speech production, but in discourse and conversation analytic branches of sociolinguistics, quantitative measures are not as common as qualitative observations. This study uses acoustic measures of hyperarticulation to quantify the effects of two interacting discourse functions: new‐information signaling and stance expression. For each of five speakers in an hour‐long political talk show, content analysis was performed on all phrases repeated three or more times to separate neutral from stance‐expressing tokens and new from given repetitions of those tokens. Word, syllable, and vowel duration were measured from spectrograms; formant (LPC) and pitch (autocorrelation) values were measured at onset, 20%, 50%, 80%, and offset of stressed vowels. Preliminary results from repeated measures analysis of variance suggest that stance is indeed a significant predictor of hyperarticulation which interacts with newness for at least some speakers. This work shows one way that acoustic.
Split-step methods for the solution of the nonlinear Schro¨dinger equation

A split-step method is used to discretize the time variable for the numerical solution of the nonlinear Schrodinger equation. The space variable is discretized by means of a finite difference and a Fourier method. These methods are analyzed with respect to various physical properties represented in the NLS. In particular it is shown how a conservation law, dispersion and instability are reflected in the numerical schemes. Analytical and numerical instabilities of wave train solutions are identified and conditions which avoid the latter are derived. These results are demonstrated by numerical examples.
Investigation of Flow Characteristics in Supersonic Cavity Using LES

The formation of large scale structures for the supersonic flow over a rectangular cavity is studied using Large Eddy Simulation (LES) and Proper Orthogonal Decomposition (POD), while the sub-grid scales (SGS) are modelled using dynamic Smagorinsky model. The Pressure distribution along the cavity walls obtained through the simulation is in good agreement with the empirical results presented in [1]. The Isosurfaces of Q show the evolution of structures inside as well as in the wake of the cavity. The contours of vorticity magnitude clearly show the flapping of the shear layer which is responsible for the generation of a feedback mechanism in the cavity. The density gradient contours show the propagation of transverse as well as longitudinal waves from the cavity. The large scale vortical structures in the mid plane along with the bending of the flow inside the cavity are captured by the POD basis functions.
On magnetic field “reconstruction”

Context. Solanki and colleagues have presented intriguing 3D “reconstructions” of magnetic fields from the vector polarimetry of the He I 1083 nm multiplet. Aims. In this Research Note I re-examine the reconstruction technique used. Methods. Using a simple dipole field, I examine the reconstruction technique as applied to the theoretical fields. I assume that the He line forms in two locations, (1) along the magnetic loops and (2) in a horizontal plane. Results. The planar interpretation can account for all aspects of the data, but the loop interpretation has geometrical and physical problems. Conclusions. The data by themselves are not sufficient to determine which picture is more applicable. Nevertheless I argue that the planar interpretation makes more physical sense and that the early reconstructions lead to spurious results. I suggest additional tests that might help constrain the problem further.
Peach maturity/quality assessment using hyperspectral imaging-based spatially resolved technique

The objective of this research was to measure the absorption (μa) and reduced scattering coefficients (μs') of peaches, using a hyperspectral imaging-based spatially-resolved method, for their maturity/quality assessment. A newly developed optical property measuring instrument was used for acquiring hyperspectral reflectance images of 500 'Redstar' peaches. μa and μs' spectra for 515-1,000 nm were extracted from the spatially-resolved reflectance profiles using a diffusion model coupled with an inverse algorithm. The absorption spectra of peach fruit presented several absorption peaks around 525 nm for anthocyanin, 620 nm for chlorophyll-b, 675 nm for chlorophyll-a, and 970 nm for water, while μs' decreased consistently with the increase of wavelength for most of the tested samples. Both μa and μs' were correlated with peach firmness, soluble solids content (SSC), and skin and flesh color parameters. Better prediction results for partial least squares models were obtained using the combined values of μa and μs' (i.e., μa × μs' and μeff) than using μa or μs', where μeff = [3 μa (μa + μs')]1/2 is the effective attenuation coefficient. The results were further improved using least squares support vector machine models with values of the best correlation coefficient for firmness, SSC, skin lightness and flesh lightness being 0.749 (standard error of prediction or SEP = 17.39 N), 0.504 (SEP = 0.92 °Brix), 0.898 (SEP = 3.45), and 0.741 (SEP = 3.27), respectively. These results compared favorably to acoustic and impact firmness measurements with the correlation coefficient of 0.639 and 0.631, respectively. Hyperspectral imaging-based spatially-resolved technique is useful for measuring the optical properties of peach fruit, and it also has good potential for assessing fruit maturity/quality attributes.
Numerical simulations of Rossby–Haurwitz waves

Simulations of Rossby–Haurwitz waves have been carried out using four different highresolutionnumerical shallow water models: a spectral model, two semi-Langrangian modelspredicting wind components and potential vorticity respectively, and a finite-volume model ona hexagonal–icosahedral grid. The simulations show that (i) unlike the nondivergent case, theshallow water Rossby–Haurwitz wave locally generates small-scale features and so has a potentialenstrophy cascade, and (ii) contrary to common belief, the zonal wavenumber 4 Rossby–Haurwitz wave is dynamically unstable and will eventually break down if initially perturbed.Implications of these results for the use of the Rossby–Haurwitz wave as a numerical modeltest case are discussed. The four models tested give very similar results, giving confidence inthe accuracy and robustness of the results. The most noticeable difference between the modelsis that truncation errors in the hexagonal–icosahedral grid model excite the Rossby–Haurwitzwave instability, causing the wave to break down quickly, whereas for the other models in theconfigurations tested the instability is excited only by roundoff error at worst, and the Rossby–Haurwitz wave breaks down much more slowly or not at all.
X-ray polarization properties of a centrally illuminated accretion disc

The polarization of the X-rays reflected by a centrally illuminated, optically thick and geometrically thin accretion disc is calculated as a function of the source and disc parameters. The degree of polarization of the reflected radiation depends strongly on the disc inclination, and could be greater than 20 per cent; the polarization angle is 90°, i.e. the polarization vector lies in the meridian plane. Due to the dilution of the primary source, assumed unpolarized, the net polarization depends strongly on photon energy, and could reach values as high as ∼6 per cent at energies greater than a few tens of keV. When relativistic effects in the Schwarzschild metric are taken into account, the degree of polarization generally increases, and the polarization angle become greater than 90°
A Non‐standard Finite Element Method for Convection‐Diffusion‐Reaction Problems on Polyhedral Meshes

We present a nonstandard finite element method for elliptic partial differential equations with piecewise constant coefficients which is based on element‐local boundary integral operators. The method is able to treat general polyhedral meshes and employs locally PDE‐harmonic trial functions. In this paper, we apply this method for the first time to convection‐diffusion‐reaction problems. We assume that the coefficients of the PDE are elementwise constant such that a fundamental solution is available locally.We perform a preliminary numerical study of the method for convection‐dominated problems in three dimensions and compare its performance for this application to a standard Finite Element Method. The results show promising stability properties.
Bootstrap Methods for Developing Predictive Models

Researchers frequently use automated model selection methods such as backwards elimination to identify variables that are independent predictors of an outcome under consideration. We propose using bootstrap resampling in conjunction with automated variable selection methods to develop parsimonious prediction models. Using data on patients admitted to hospital with a heart attack, we demonstrate that selecting those variables that were identified as independent predictors of mortality in at least 60%% of the bootstrap samples resulted in a parsimonious model with excellent predictive ability.
Solar wind and substorm‐related changes in the lobes of the geomagnetic tail

Variations in the magnetic energy density in the lobes of the geomagnetic tail appear to be fundamentally associated with magnetospheric substorms. Thus in this paper the relationship of the tail lobe energy density to solar wind dynamic pressure, the north-south component of the interplanetary magnetic field, and substorm expansion onsets is investigated. Enhanced lobe energy densities are observed to follow both southward turnings of the interplanetary magnetic field and solar wind dynamic pressure increases. An empirical relationship is developed relating the tail lobe magnetic energy density to the solar wind dynamic pressure by using data obtained when the interplanetary field was northward. Localized, off-center, or multiple-onset substorm expansion phases are shown to have little effect on the lobe magnetic field. A positive correlation is found between magnetospherewide substorm expansions and decreases in the lobe energy density. The positive correlation of the energy density with both the solar wind dynamic pressure and a southward interplanetary magnetic field and the positive correlation between magnetospheric substorm activity and lobe energy density decreases are demonstrated to be consistent with our phenomenological model of substorm behavior.
Thermoelastic Response of Cross-Ply Laminated Shells Based on a Rigorous Shell Theory

Thermal deformations in cross-ply laminated shells are investigated. The state space approach is used to generate exact solutions for the thermoelastic response of cross-ply spherical, cylindrical and doubly curved shells for various boundary conditions and subjected to general temperature field. The shells possess two parallel edges simply supported and the remaining ones having any possible combination of boundary conditions: free, clamped or simply supported. A rigorous thick deep first order shear deformation shell theory is used in the analysis. Deflections are computed for shells with various boundary conditions undergoing uniform and linearly varying temperature through the thickness. The exact solutions for thermal deflections can be used as benchmarks for approximate solutions such as Rayleigh-Ritz and finite element methods.
VISCOUS DISSIPATION AND JOULE HEATING EFFECTS ON STEADY MHD COMBINED HEAT AND MASS TRANSFER FLOW THROUGH A POROUS MEDIUM IN A ROTATING SYSTEM

Normal 0 MicrosoftInternetExplorer4 Viscous dissipation and Joule heating effects on steady MHD combined heat and mass transfer flow through a porous medium along a semi-infinite vertical porous plate in a rotating system has been studied numerically. The boundary layer equations have been transformed into dimensionless coupled nonlinear ordinary differential equations by appropriate transformations. The similarity solutions of the transformed dimensionless equations for the flow field and heat and mass transfer characteristics are obtained by shooting iteration technique. Numerical results are presented in the form of primary and secondary velocities, temperature and concentration distributions within the boundary layer for different parameters entering into the analysis. Finally, the effects of the pertinent parameters on the Skin-friction coefficients, Nusselt number and Sherwood number are also examined. Keywords: MHD; Joule heating; porous medium; rotating system simulation. doi: http://dx.doi. org/10.3329/jname.v8i2. 5055 Journal of Naval Architecture and Marine Engineering 8(2011) 105-120
Quantitative Evaluation of Experimental Results an the Heterogeneous Freezing Nucleation of Supercooled Liquids

Abstract Freezing experiments using large numbers of small drops are frequently used for the study of both homogeneous and heterogeneous nucleation of water and of other substances. For heterogeneous nucleation, the spread in the observed freezing temperatures of drops has been shown to arise from the presence of nuclei of different activities in the sample. In the past no quantitative assessment of the nucleus content could be given independent of the drop sizes used. It is shown in this paper that from the observed freezing temperatures of the drops one can derive both a differential and a cumulative nucleus spectrum. The differential spectrum represents the concentrations of nuclei which are active at specific temperatures and the cumulative spectrum represents the concentrations of nuclei active at all temperatures warmer than the selected temperature. The accuracies of the derived spectra were examined by Monte Carlo simulation and are shown to be such that the concentrations are reliable to within f.
Selective spatial attention in a dynamic cocktail party task: Evidence for a strategy based on masker minimization

In cocktail‐party listening tasks with multiple spatially separated talkers, it is not clear whether the performance advantages of spatial separation are the result of a target‐max strategy, where the listener uses selective attention to enhance sensitivity at the location of the target, or a masker‐min strategy, where the listener selectively suppresses sensitivity at the locations of the maskers. In this experiment, listeners were asked to attend to a randomly moving CRM target phrase that was masked by two independently moving CRM masking phrases. The competing signals were lateralized solely on the basis of ITD, and they were band‐pass filtered into non‐overlapping bands to minimize the effects of energetic masking. The results of the experiments showed (1) that listeners were much more sensitive to changes in the masker locations than to changes in the target location; (2) that listeners consistently performed worse when the two maskers were spatially separated than when they were co‐located, even wh.
Nonlinear Dynamics of Bladed Disks with Multiple Unstable Modes

A simple model that describes the nonlinear dynamics of bladed disks due to dry friction exerted in the attachment of the rotor blades with the disk, and the unsteady aerodynamic forces induced by the vibration of aerodynamically unstable airfoils, is presented and analyzed. The analysis is focused on a simplified case whose dynamics is representative of a high aspect ratio low-pressure turbine rotor blade. A parametric study is conducted to understand the dynamics of the the problem for times much longer than the fundamental period of the rotor blades, when the effect of the initial conditions is not relevant and a periodic steady state has been reached. It is concluded that the conjecture that the dynamics of multimode unstable bladed disk, in the absence of external periodic forcing, finally reaches a state in which only a single traveling wave exists is true and that this behavior may be reproduced also using simplified models.
The extended narrow line region of NGC 4151.: I. Emission line ratios and their implications

The paper presents the first results from long-slit spectra of the Seyfert galaxy NGC 4151 which give average diagnostic ratios of weak lines in the Extended Narrow Line Region (ENLR) of the galaxy and the first direct density measurement in an ENLR. These data confirm that the ENLR is kinematically undisturbed gas in the disk of the galaxy which is illuminated by an ionizing continuum stronger by a factor of 13 than a power law interpolated between recently observed ultraviolet and X-ray fluxes. Explanations of this apparent excess include a hot thermal continuum, time variations, and an anisotropic rotation field.
Exchange Rate Disconnect Revisited

We find that variation in expected U.S. productivity explains over half of G6 exchange rate fluctuations vis-a-vis the USD. Both correctly-anticipated changes in productivity and expectational “noise,” which influences expectations of productivity but not the actual realization, have significant effects on exchange rates. Together, these two types of disturbances explain many unconditional exchange rate patterns, including predictable excess returns, low Backus-Smith correlations, and excess volatility. Our findings suggest these well-known puzzles have a common empirical origin, which is linked to (expected) productivity. We also discuss how noise in expectations has obscured the relationship between exchange rates and fundamentals in the empirical approaches undertaken in prior work. JEL Codes: D8, F3, G1
Investigations of harmonic generations in aperiodic optical superlattices

We envisage the enhanced effect of harmonic generations from aperiodic optical superlattices (AOSs) achieved by inverting poled ferroelectric domains in samples. The search of optimal AOSs structures belongs to solving a difficult inverse source problem in nonlinear optics. We employ the simulated annealing method to successfully deal with this problem. We present the analyses of the design idea in the real-space representation and carry out several model designs. The constructed AOSs implement multiple wavelength second-harmonic generation and the coupled third-harmonic generation with an identical effective nonlinear coefficient at the preassigned wavelengths. The simulations show that the harmonic generations in the constructed AOSs can approach the prescribed goal better than those with the Fibonacci optical superlattice. The effective nonlinear coefficients versus the optical wave propagating distance from the impinging surface of incident light in the sample exhibit monotonically increasing behavior.
Improved image deblurring with anti-reflective boundary conditions and re-blurring

Anti-reflective boundary conditions (BCs) have been introduced recently in connection with fast deblurring algorithms. In the noise free case, it has been shown that they substantially reduce artefacts called ringing effects with respect to other classical choices (zero Dirichlet, periodic, reflective BCs) and lead to O(n2log(n)) arithmetic operations, where n2 is the size of the image. In the one-dimensional case, for noisy data, we proposed a successful approach called re-blurring: more specifically, when the PSF is symmetric, the normal equations product ATA is replaced by A2, where A is the blurring operator (see Donatelli et al 2005 Inverse Problems 21 169–82). Our present goal is to extend the re-blurring idea to nonsymmetric point spread functions (PSFs) in two dimensions. In this more general framework, suitable for real applications, the new proposal is to replace AT by A′ in the normal equations, where A′ is the blurring matrix related to the current BCs with PSF rotated by 180°. We notice that, although with zero Dirichlet and periodic BCs the re-blurring approach is equivalent to the normal equations scheme, since there A′ = AT, the novelty concerns both reflective BCs and anti-reflective BCs, where in general A′ ≠ AT. We show that the re-blurring with anti-reflective BCs is computationally convenient and leads to a large reduction of the ringing effects arising in classical deblurring schemes. A wide set of numerical experiments concerning 2D images and nonsymmetric PSFs confirms the effectiveness of our proposal.