Miracle-dz/UniFAR-FTUs huggingface dataset:
Evaluating super resolution algorithms

This study intends to establish a sound testing and evaluation methodology based upon the human visual characteristics for appreciating the image restoration accuracy; in addition to comparing the subjective results with predictions by some objective evaluation methods. In total, six different super resolution (SR) algorithms - such as iterative back-projection (IBP), robust SR, maximum a posteriori (MAP), projections onto convex sets (POCS), a non-uniform interpolation, and frequency domain approach - were selected. The performance comparison between the SR algorithms in terms of their restoration accuracy was carried out through both subjectively and objectively. The former methodology relies upon the paired comparison method that involves the simultaneous scaling of two stimuli with respect to image restoration accuracy. For the latter, both conventional image quality metrics and color difference methods are implemented. Consequently, POCS and a non-uniform interpolation outperformed the others for an ideal situation, while restoration based methods appear more accurate to the HR image in a real world case where any prior information about the blur kernel is remained unknown. However, the noise-added-image could not be restored successfully by any of those methods. The latest International Commission on Illumination (CIE) standard color difference equation CIEDE2000 was found to predict the subjective results accurately and outperformed conventional methods for evaluating the restoration accuracy of those SR algorithms.
Perception of stops in naturally produced V[l/r][b/d/g]V tokens: a reassessment of acoustic cues to place of articulation

This perceptual experiment reassesses a traditional assumption that the F3 transition is the primary cue for distinguishing [da] from [ga], evidence of which comes from perceptual experiments using synthetic continua [Mann, Percept. Psychophys. 5, 407–412 (1980); Fowler et al., ibid. 48, 559–570 (1990); Liberman, Speech (1996)]. Stimuli were tokens of /alba/, /alda/, /alga/, /arba/, /arda/, /arga/ produced three times by four speakers at three rates (fast, normal, slow), analyzed acoustically by Dainora et al. [J. Acoust. Soc. Am. 100, 2601 (1996)] and Hemphill et al. [CLS 33, 333–346 (1997)]. Subjects identified tokens in their original carrier sentences using a forced choice paradigm. Stimuli were blocked by speaker and rate; three repetitions of each were randomized within blocks. In five of the 216 tokens, for one or more subjects, the percept of the stop did not match the speaker’s intent. Analysis of these tokens showed a mismatch between formant transitions and burst spectra: formant transitions we.
Multivariate analysis-based image enhancement model for machine vision inspection

Image enhancement is an essential procedure in machine vision-based inspection. In practical applications, image enhancement is usually a part of image pre-processing, intended to make the following inspection more effective. The image enhancement method is usually selected by trial-and-error or on the basis of experience. This paper presents an automatic procedure for fast and effective image enhancement. The procedure uses multivariate analysis to automatically construct an optimal image enhancement model. First, an optimally enhanced image was selected from the literature as a basis for the model. Then, the image features were identified and Wilks’ statistic was used for feature selection. Next, discriminate functions were built to select the optimal image enhancement method. To verify the model, 53 training images from the literature and 12 test images from a local company were used in an experimental analysis. The model achieved 98.11% accuracy in selecting the most suitable image enhancement method, and the average increase in contrast was 98% for the 53 training images. The enhancement method selection results for the 12 test images were also in agreement with the 53 training images from the literature. The results show that the proposed method is effective and appropriate for quickly improving image contrast.
Integral Field Spectroscopic Data Reduction Method for High Resolution Infrared Observation

We introduce a technical approach for reducing three-dimensional infrared (IR) spectroscopic data generated by integral field spectroscopy or slit-scanning observations. The first part of data reduction using IRAF presents a guideline for processing spectral images from long-slit IR spectroscopy. Multichannel image reconstruction, Image Analysis and Display (MIRIAD) is used in the later part to construct and analyze the data cubes which contain spatial and kinematic information of the objects. This technic has been applied to a sample data set of diffuse 2.1218 1-0 S(1) emission features observed by slit-scanning around Sgr A East in the Galactic center. Details of image processing for the high-dispersion infrared data are described to suggest a sequence of contamination cleaning and distortion correction. Practical solutions for handling data cubes are presented for survey observations with various configurations of slit positioning.
Radiation characteristics and performance of millimeter-wave horn-fed Gaussian beam antennas

Radiation characteristics and performance of Gaussian beam antennas (GBAs) are studied theoretically and experimentally in the 60 GHz band. A GBA consists of a plano-convex half-wavelength Fabry-Perot (FP) resonator excited by a guided source with a metal flange. Two reflecting metal mesh mirrors are formed on both faces of the cavity. After a review of the principles and quasi-optical performance of plano-convex FP resonators illuminated by a plane wave, a new formulation is proposed to compute the radiation patterns of GBAs: the usual expression of the waist radius inside open resonators is modified to account for the horn aperture and for the grid parameters of the plane mirror. Standard closed-form relations of vector Gaussian beams are then used to compute the radiated copolar components. In particular, it is shown that the plane mirror is not an equiphase surface, due to the metal flange of the horn. The true phase distribution is approximated by a spherical wavefront. As a result, the directivity of the antenna becomes lower than its quasi-optical value. Experimental data obtained at 60 GHz with several pyramidal horns and various cavities agree very well with the theory. Sidelobes are lower than -25 dB, and the cross-polarization level is the same as that of the primary radiator. Universal curves showing the variations of resonant frequency, -3 dB bandwidth, gain, and radiation efficiency as a function of mirror reflectivity are very useful for the design of GBAs.
The subdirect decomposition theorem for classes of structures closed under direct limits

Abstract By a theorem of G. Birkhoff, every algebra in an equationally defined class of algebras K is a subdirect product of subdirectly irreducible algebras of K. In this paper we show that this result is true for any class of structures. not necessarily algebraic, closed under isomorphisms and direct limits. Quasivarieties in the sense of Malcev are examples of such classes of structures. This includes Birkhoffs result as a particular case.
Bayesian deconvolution with prior knowledge of object location : applications to ground-based planetary images

A Bayesian method to deconvolve images when the location of the objects in the image is known in advance is presented. This knowledge of location is incorporated into the prior model via a labeling process. An iterative method is proposed to find the maximum a posteriori estimator of the image. The method was tested on both synthetic images and ground-based CCD images of Saturn with very encouraging results
A preliminary investigation on an ELLAM scheme for linear transport equations

We present an Eulerian‐Lagrangian localized adjoint method (ELLAM) for linear advection‐reaction partial differential equations in multiple space dimensions. We carry out numerical experiments to investigate the performance of the ELLAM scheme with a range of well‐perceived and widely used methods in fluid dynamics including the monotonic upstream‐centered scheme for conservation laws (MUSCL), the minmod method, the flux‐corrected transport method (FCT), and the essentially non‐oscillatory (ENO) schemes and weighted essentially non‐oscillatory (WENO) schemes. These experiments show that the ELLAM scheme is very competitive with these methods in the context of linear transport PDEs, and suggest/justify the development of ELLAM‐based simulators for subsurface porous medium flows and other applications. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 19: 22–43, 2003
Discovery of an X-ray burst source XB 1715-321

A new X-ray burst source, XB 1715-321, was discovered with the Hakucho satellite. Three type I X-ray bursts were observed from this source in 1979. The error region for XB 1715-321, about 0.3 square degrees in area, includes a persistent X-ray source MX/2S 1715-321 which has been suspected to be the source of several fast transient events. Those bursts detected by Hakucho are characterized by a slow rise time (5--10 s) and a relatively long burst interval.
Physical modeling of an eddy current sensor designed for real time distance and thickness measurement in galvanization industry

An analytical model of an eddy current sensor designed for noncontact thickness and distance measurement is presented. A dipolar model allows the external physical parameters (conductivity and permeability of alloys) to be taken into account. Analysis of an iron sheet coated with a conductive material gives an accurate interpretation of the detected signals, useful for optimization of the sensor design. Experimental and theoretical data are compared for a galvanization line, demonstrating the potential of this system for nondestructive continuous evaluation. >
Some uniqueness theorems for the ideal MHD equilibrium of a cylindrical tokamak

The cylindrical MHD equilibrium equation is formulated in a manner suitable for numerical computations which require the application of a constraint. In this formulation a uniqueness theorem is proved for a free boundary equilibrium with a specified total current. Uniqueness is independent of the details of the current density and merely requires that the total current is compatible with the current density. Two uniqueness theorems for diffuse plasmas are also presented. Four free boundary examples are studied with a variety of constraints applied.
Wave energy dissipation by phase mixing in magnetic coronal plasmas

Wave energy dissipation by viscous and resistive damping in magnetic coronal plasmas is examined. We begin by pointing out that since the dimensionless viscous damping coefficient ν is generally much greater than the dimensionless resistivity η, viscous dissipation can be expected to be the dominant mechanism in many coronal applications. A detailed analysis is presented for the case of perpendicular polarized shear wave disturbances which propagate in a horizontally stratified magnetic channel. We show that when the equilibrium field contains a neutral line (specifically, B = B0y x ) the development of small length scales by phase mixing � � (η + ν) 1/3 leads to efficient wave energy losses: in particular, the bulk of the energy losses take place over the time interval (η + ν) −1/3 . However, the later stages of the decay depends critically on whether viscosity or resistivity provides the dominant damping mechanism. When resistivity is sufficiently small the decay rate weakens at later times due to the emergence of a self-similar mode which allows a separation of the global kinetic and magnetic energies (ν � η). If the resistivity is large enough but still not dominant, self-similar behaviour can give way to monotonic exponential damping on the visco-resistive length scale � � (ην) 1/6 . In either case, provided only that ν>η , energy equipartition eventually breaks down and the remnants of the initial wave energy wind up mainly in the magnetic field.
A meshless based solution to vectorial mode fields in optical microstructured waveguides

A meshless solution to vectorial mode fields has been applied to various micro-structured optical waveguides. The Finite Cloud Method (FCM), has been used to solve coupled field equations for both transverse components of the magnetic field as well as the effective index of refraction for the waveguides. Two methods using either a step-index or a graded-index have been implemented and compared. An approximation to the solution is found using a distribution of points and a cloud about each point, with no mesh and minimal geometric linking knowledge between the points. This gives the ability to use a highly irregular point distribution which can be easily modified or tailored to micro-structured fibers in order to accurately represent the vectorial modal solution. In addition, the use of Bayliss-Gunzburger-Turkel-like transparent boundary conditions (TBC) and an iterative process is compared with a perfectly matched layer (PML), both of which allow for the solution of leaky modes for the structures. Results for ridge waveguides and solid core fibers having low index contrast are in high agreement with the solutions from commercial solvers. Further results with high contrast air hole structures are compared with other solution methods giving promising results and highlight this methods versatility, accuracy and efficiency for a wide range of problems.
Reducing the sensitivity of a free‐electron laser to electron energy

A technique is described which allows a free‐electron laser to utilize an electron beam with a wide energy spread. A laser using this technique can be powered by a greater variety of electron sources than would otherwise be possible. In addition, the techniques ease some of the problems encountered when designing a laser to operate in conjunction with a storage ring.
Calculation of gravity and magnetic anomalies of finite‐length right polygonal prisms

An equation is derived for the vertical gravity field due to a homogeneous body with polygonal cross‐section and finite strike‐length. The equation can be separated into the two‐dimensional (2-D) terms of Talwani et al. (1959) and exact terms for the contributions of the ends of the prism. Equations for the magnetic field due to a similar body were derived by Shuey and Pasquale (1973), who coined the term “two‐and‐a‐half dimensional” (212-D) to describe the geometry. Magnetic intensities are expressed as a vector sum, from which the common dot product formulation can be obtained by binomial expansion.
Robust speech event detection using strictly temporal information

A major problem in the development of robust speech recognition systems is our understanding of how to deal with noise and/or reduced spectral information. Previous studies have shown that the temporal structure of speech is robust and a good source of information for recognizing manner. This work discusses the development of algorithms that specifically target temporal information in the speech signal that can be used to identify different manner classes. In particular, we extract events associated with sonorant regions and obstruent regions. We compared the performance of our algorithms on clean speech (sentences taken from the TIMIT database) and on 1 channel spectrally impoverished speech [as described by Q. ‐J. Fu, House Ear Institute, Dept. of Auditory Implants and Perception, Tigersoft]. The results show no degradation in performance for the detection of landmarks associated with stops, affricates, strident fricatives, and vowels. There is a small degradation of six landmarks associated with the ‘‘w.
An inverse resistivity problem: 1. Lipschitz continuity of the gradient of the objective functional

A mathematical model of vertical electrical sounding over a medium with continuously changing conductivity σ(z) is studied by using a resistivity method. The considered model leads to an inverse problem of identification of the unknown leading coefficient σ(z) of the elliptic equation in the layer Ω = {(r, z) ∈ R 2 : 0 ≤ r < ∞, 0 < z < H}. The measured data is assumed to be given on the upper boundary of the layer, in the form of the tangential derivative. The proposed approach is based on transformation of the inverse problem, by introducing the reflection function p(z)=(ln σ(z))′ and then using the Bessel–Fourier transformation with respect to the variable r ≥ 0. As a result the inverse problem is formulated in terms of the transformed potential V(λ, z) and the reflection function p(z). It is proved that the transformed cost functional is Fréchet differentiable with respect to the function p(z). Moreover, an explicit formula for the Fréchet gradient of the cost functional is derived. Then Lipschitz continuity of this gradient is proved in class of reflection functions p(z) with Hölder class of derivative p′(z).
Size classification of silicon nanocrystals

We report on the synthesis of size-classified silicon nanocrystals by differential mobility classification of a polydisperse ultrafine silicon aerosol. Using the described technique, the average nanocrystal size can be tuned by simply adjusting an electric field. Samples of nonagglomerated silicon nanocrystals have been obtained and size control has been achieved within 15%–20% in the 2–10 nm size regime.
Small axial flux motor with permanent magnet excitation and etched airgap winding

Disc-type motors with sintered Nd-Fe-B magnets benefit from the high remanence and near-ideal loop shape of the hard magnetic material. Consequent advantages include a high torque for a given motor size and improved efficiency. Special airgap windings manufactured as multilayer etched windings contribute to flat package motors and to low torque harmonics. Different back iron designs were examined. For the operation of the brushless DC motor, instead of the classical Hall sensors, small magnetoresistive sensors can be used effectively for rotor position sensing. >
Dynamic Prediction by Landmarking in Event History Analysis

This article advocates the landmarking approach that dynamically adjusts predictive models for survival data during the follow up. This updating is achieved by directly fitting models for the individuals still at risk at the landmark point. Using this approach, simple proportional hazards models are able to catch the development over time for models with time-varying effects of covariates or data with time-dependent covariates (biomarkers). To smooth the effect of the landmarking, sequences of models are considered with parametric effects of the landmark time point and fitted by maximizing appropriate pseudo log-likelihoods that extend the partial log-likelihood to cover the landmarking approach. Copyright 2007 Board of the Foundation of the Scandinavian Journal of Statistics.
Cat's eye radiation with boundary elements: comparative study on treatment of irregular frequencies

This paper reviews a number of techniques developed to overcome the well-known nonuniqueness problem in boundary integral formulations of acoustic radiation. Although the problem has received much attention, comparative studies are hardly known in this field. Furthermore, the problem has often been studied using an unsuitable example, namely a simple radiating sphere. In this case, often the addition of one collocation point in the centre of the sphere suffices to remove the nonuniqueness problem for a large range of wavenumbers. In contrast to the radiating sphere, the radiating cat's eye structure is considered in this paper. Solution of the discretized ordinary Kirchhoff–Helmholtz integral equation, also known as the Surface Helmholtz Equation, reveals a large number of so-called irregular frequencies, i.e. frequencies where the BEM fails. The paper compares the performance of different methods in alleviating this failure. The CHIEF method and its variation due to Rosen et al. are found to encounter difficulties at high frequencies. A much better performance is obtained by combining the Kirchhoff–Helmholtz integral equation with its normal derivative. In particular the method of Burton and Miller and a modification of it which avoids evaluating the hypersingular operator at nonsmooth points are tested. Both methods seem to provide reliable solutions. The modified method encounters minor failures in the frequency response function at a geometric singularity, although performing surprisingly well in many cases. More tests need to be carried out to assess fully the effectiveness of this method which allows easy use of continuous quadratic elements. However, it is the Burton and Miller formulation which appears to be the most reliable for acoustic radiation analysis. The use of CHIEF and its variations cannot be recommended.
Process control and machine learning: rule-based incremental control

In this paper, we discuss a rule-based incremental control program which has been used for controlling a laser cutting robot and in simulation for driving a car on a track, for a car parking manoeuvre, or for parking a truck with one trailer. The core of the paper concerns a learning program, Candide, which learns to control a process without a priori knowledge about the process, by observing random initial evolutions of the process and acquiring a qualitative model. Monotonous or derivative relationships between inputs and outputs are recognized, and then a rule-based incremental controller Is deduced from this model. >
Exploring the validity of the Spalart-Allmaras turbulence model for hypersonic flows

The Spalart‐ Allmaras turbulence model has been implemented in a e nite volume code using an implicit e nite difference technique. First, the implementation was validated on e at plate turbulent boundary-layer e ows under various e ow conditions. Then, three high-speed e ow applications characterized by different turbulent phenomena were considered to investigate the behavior of the Spalart‐ Allmaras model in the hypersonicregime, namely, a hypersonicwind-tunnel e ow, a Mach 5 e owovera hollow-cylinder e are, and aMach 6.8 e ow overa hyperboloid e are. Numerical results were found in excellent agreement with experimental data for the attached nozzle e ow and the hyperboloid e ow involving laminar separation and turbulent reattachment. For the hollow-cylinder e are cone guration,whichinvolvesturbulentseparation,themagnitudesofsurfacepressureandofheattransferpeakswerecorrectly predicted,whereastheirpositionswereslightly incorrectdueto theunderprediction of theseparationbubble size. Nomenclature bdest = destruction term, m 2 s i2 bprod = production term, m 2 s i2 btrip = trip term, m 2 s i2
Photoconductivity in Ag2O

The spectral distribution of photoconductivity in Ag2O was measured on samples prepared in three different ways. The photoresponse was found to depend on the mode of preparation of samples and on previous light exposure. Samples prepared by pressing Ag2O powder against a cellulose backing showed a photoconductive peak around 0.9 μm, while thin Ag2O layers prepared by cathodic sputtering of silver in an oxygen atmosphere behaved like the ideal photoconductors: flat response in the visible and exponential decrease from 0.8 μm to longer wavelengths. Some infra-red optical absorption and electrical conductivity measurements were also made. The results are compared to the behaviour of Cu2O, silver oxide's only structural analogue.