Miracle-dz/UniFAR-FTUs huggingface dataset:
Role of processing geometry in SAR raw data focusing

Synthetic aperture radar (SAR) systems require that a focusing operation be performed on the received backscattered echoes (raw data) to generate high-resolution microwave images. Either due to platform attitude instabilities, or to Earth rotation effects, the SAR raw data may be acquired in "squinted" geometries, i.e., with the radar beam directed with an offset angle (squint angle) from the broadside direction. This research investigates the impact of the focusing operation carried out on squinted raw data acquisitions performed by SAR sensors operating in the stripmap mode. To this end the 2D frequency SAR processing approach is generalized with respect to conical, i.e., nonorthogonal, reference systems. This allows analysis of the geometric, spectral, and phase aberrations introduced in the images by the chosen processing geometry with respect to the acquisition, and identification of the focusing procedure that minimizes these aberrations. The whole theory is validated by experimental results carried out on simulated data. Moreover, the extension of this analysis to the interferometric case where these aberrations may have a significant role is also investigated.
Modal Decoupling of Systems Described by Three Linear Operators 7

consider carefully the physical aspects of the problem. Otherwise, one may find oneself solving a mathematical problem that does not have a sound physical basis. The new formulation of the Lagrange method that was recently presented by Rosen and Edelstein, seems to offer a unified variational approach to both holonomic and nonholonomic constraints. For a simple example that was present above the new formulation gave results that were identical to the results of a Newtonian approach, while the "regular" approach to nonholonomic constraints failed to do that. The authors obtained similar results in other examples (Rosen and Edelstein, 1997b). Yet, the authors by no means feel that the difficulty of solving nonholonomic problems is over. The new formulation seems to be promising, but many more careful examinations of it are necessary in order to gain more confidence in its capabilities, further improve its performance, and knowing its limitations. The authors invite other researchers to test, extend, and improve the new formulation. For example, Eq. (18) can be extended to deal with Lagrangians that include derivatives higher than the second. If there exist problems that include high derivatives, the results of such an extension may be interesting. Before closing, the authors would like to again thank Professor Hagedorn for his interesting and stimulating discussion.
Extending pure luminosity evolution models into the mid-infrared, far-infrared and submillimetre

Simple pure luminosity evolution (PLE) models, in which galaxies brighten at high redshift due to increased star formation rates (SFRs), are known to provide a good fit to the colours and number counts of galaxies throughout the optical and near-infrared. We show that optically defined PLE models, where dust reradiates absorbed optical light into infrared spectra composed of local galaxy templates, fit galaxy counts and colours out to 8 μm and to at least z≈ 2.5. At 24–70 μm, the model is able to reproduce the observed source counts with reasonable success if 16 per cent of spiral galaxies show an excess in mid-IR flux due to a warmer dust component and a higher SFR, in line with observations of local starburst galaxies. There remains an underprediction of the number of faint-flux, high-z sources at 24 μm, so we explore how the evolution may be altered to correct this. At 160 μm and longer wavelengths, the model fails, with our model of normal galaxies accounting for only a few percent of sources in these bands. However, we show that a PLE model of obscured AGN, which we have previously shown to give a good fit to observations at 850 μm, also provides a reasonable fit to the Herschel/BLAST number counts and redshift distributions at 250–500 μm. In the context of a ΛCDM cosmology, an AGN contribution at 250–870 μm would remove the need to invoke a top-heavy IMF for high-redshift starburst galaxies.
Journal of Quantitative Analysis in Sports Tweaking the NFL ’ s Quarterback Passer Rating for Better Results

In recent years, the NFL’s quarterback passer rating has become one of the most widely recognized statistics in sports. Though it has been in use since 1973, popular acceptance of the statistic took a few decades and has resulted in a great deal of debate over its ability to effectively quantify an aspect of the quarterback’s performance. Here, we will offer some background on the current quarterback passer rating system, consider some prevalent criticisms of the rating and propose some minor modifications to the rating system designed to keep the original intent of the statistic intact, while significantly improving results. Thus, rather than to offer a newly designed statistic, the goal here is to offer the simplest of modifications to the current quarterback passer rating, in line with the established calculation procedure, which will improve the effectiveness of the statistic. We will show that these modifications produce results that are far more reasonable than those achieved by the current rating.
DYNAMIC RESPONSE AND WAVE PROPAGATION IN THREE-DIMENSIONAL FRAMED STRUCTURES

This paper extends the recently developed method of reverberation-ray matrix for planar structures to three-dimensional framed structures. The propagation of steady state axial, flexural and torsional waves, as well as the mode conversions through scattering of all three waves at connecting joints are evaluated in the frequency domain. The transient waves in all members are then determined by the Fourier synthesis. The transient responses of a two-storey framed building subject to a step time loading are calculated in detail. Numerical results are obtained for early time as well as moderately long time records. The results are shown to be accurate in arrival times of all three types of waves and in asymptotic values at times.
CLASSES OF OPERATOR-SMOOTH FUNCTIONS. III. STABLE FUNCTIONS AND FUGLEDE IDEALS

Abstract This paper continue to study the interrelation and hierarchy of the spaces of operator-Lipschitz functions and the spaces of functions closed to them: commutator bounded and operator stable. It also examines various properties of symmetrically normed ideals, introduces new classes of ideals: regular and Fuglede, and investigates them. AMS 2000 Mathematics subject classification: Primary 47A56; 47L20
Discrete-time robot visual feedback in 3D positioning tasks with depth adaptation

An adaptive visual feedback scheme is designed to perform 3D positioning tasks. The dynamic camera-object interaction model is derived in discrete time, since the visual sampling time is not negligible at the current state of technology. Active contours are used to track the 2D projection of the visible object's surface in the image plane. Uniform asymptotic stability of the image reference set-point is proved using the Lyapunov direct method, and a 3D estimation procedure, based on prediction errors, is used to cope with the unknown depth of the object. Experimental results with a 6-DOF robot manipulator in eye-in-hand configuration validate the theoretical framework in real conditions.
Critical layer and radiative instabilities in shallow-water shear flows

Abstract In this study a linear stability analysis of shallow-water flows is undertaken for a representative Froude number $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}F=3.5$ . The focus is on monotonic base flow profiles $U$ without an inflection point, in order to study critical layer instability (CLI) and its interaction with radiative instability (RI). First the dispersion relation is presented for the piecewise linear profile studied numerically by Satomura (J. Meterol. Soc. Japan, vol. 59, 1981, pp. 148–167) and using WKBJ analysis an interpretation given of mode branches, resonances and radiative instability. In particular surface gravity (SG) waves can resonate with a limit mode (LM) (or Rayleigh wave), localised near the discontinuity in shear in the flow; in this piecewise profile there is no critical layer. The piecewise linear profile is then continuously modified in a family of nonlinear profiles, to show the effect of the vorticity gradient $Q^{\prime } = - U^{\prime \prime }$ on the nature of the modes. Some modes remain as modes and others turn into quasi-modes (QM), linked to Landau damping of disturbances to the flow, depending on the sign of the vorticity gradient at the critical point. Thus an interpretation of critical layer instability for continuous profiles is given, as the remnant of the resonance with the LM. Numerical results and WKBJ analysis of critical layer instability and radiative instability for more general smooth profiles are provided. A link is made between growth rate formulae obtained by considering wave momentum and those found via the WKBJ approximation. Finally the competition between the stabilising effect of vorticity gradients in a critical layer and the destabilising effect of radiation (radiative instability) is studied.
Multiple positive solutions for semi‐linear elliptic systems involving sign‐changing weight

In this paper, we study the multiplicity results of positive solutions for a semi‐linear elliptic system involving critical growth terms. With the help of Nehari manifold and Ljusternik‐Schnirelmann category, we investigate how the coefficient h(x) of the critical nonlinearity affects the number of positive solutions of that problem and get a relationship between the number of positive solutions and the topology of the global maximum set of h. Copyright © 2014 John Wiley & Sons, Ltd.
A WIYN NEAR-INFRARED INVESTIGATION OF THREE MASSIVE STAR-FORMING REGIONS

We investigate three embedded massive star-forming regions using the Near-Infrared Imager (NIRIM) camera on the 3.5 m WIYN telescope. We report J-, H-, and K′-band photometry in the clusters AFGL437, AFGL5180, and AFGL5142, and use these results to probe the stellar populations, extinction, and ages of the clusters. We find that all three clusters suffer significant extinction (AK ∼ 1), have ages ⩽ 5 Myr, and are actively forming stars. The background-corrected percentages of cluster members identified as young stellar objects (YSOs) in AFGL437, AFGL5180, and AFGL5142 are 58% ± 15%, 75% ± 10%, and 78% ± 15%, respectively. The slopes of the K-band luminosity functions (KLFs) for these clusters are ∼0.3–0.4, similar to that in other young clusters. Both the percentage of YSOs and KLF slopes of these clusters indicate that their ages are <5 Myr. We investigate the consequences of incompleteness in areas of high background emission and stellar density, and find that it contributes significant uncertainty to the determination of cluster properties. We find that age determination using only near-IR (NIR) photometry has an uncertainty of ∼3 Myr.
Grazing-incidence measurements of L-shell line emission from highly charged Fe in the soft x-ray region

Line emission from highly charged ions in the soft x-ray region represents an important diagnostic for high-temperature plasmas. The wavelength region of 10–30 A is occupied by lines from the K-shell transitions in N through Ne and L-shell transitions in Ti through Ni. Crystal spectrometers have previously been used to investigate Fe line radiation under well controlled conditions using the LLNL electron beam ion trap facility in this wavelength region. To complement this work we have instituted a grazing-incidence spectrometer with a variable line-spaced, concave grating and a flat field of focus which is suited for a multichannel detector. Simultaneous observations of the Ne-like Fe16+ n=3→2 transitions were made with this instrument and a flat-crystal spectrometer in order to establish the linear polarization of the Fe XVII lines. We present a description of the grating spectrometer and discuss its performance in comparison with Rowland circle based grazing incidence instruments.
Turbulent velocity fluctuations need not be Gaussian

It is noted that the central limit theorem does not constrain the probability distribution of the components of the turbulent velocity fluctuations to be Gaussian, if their spectral slope is steeper than k−1. It is shown that, in a model of homogeneous turbulence in which each wavenumber of the energy spectrum predominantly receives contributions from eddies with roughly homogeneous amplitudes and coherence lengths, the p.d. f. would be slightly sub-Gaussian. This agrees with the available experimental evidence.
Resolvent Tests for Similarity to a Normal Operator

The main result of this paper is the resolvent similarity criterion which says that linear growth of the resolvent towards the spectrum is sufficient for a Hilbert space contraction with finite rank defect operators and spectrum not covering the unit disc to be similar to a normal operator. Similar results are proved for operators having a spectral set bounded by a Dini‐smooth Jordan curve; in particular, a dissipative operator with finite rank imaginary part is similar to a normal operator if and only if its resolvent grows linearly towards the spectrum. Relevant results on the insufficiency of linear resolvent growth not accompanied by smallness of defect operators are presented. Also it is proved that there is no restriction on the spectrum, other than finiteness, which together with linear resolvent growth implies similarity to a normal operator. The construction of corresponding examples depends on a characterization of well‐known Ahlfors curves as curves of linear length growth with respect to linear fractional transformations. 1991 Mathematics Subject Classification: 11D25, 11G05, 14G05.
An efficient empirical likelihood approach for estimating equations with missing data

We explore the use of estimating equations for efficient statistical inference in case of missing data. We propose a semiparametric efficient empirical likelihood approach, and show that the empirical likelihood ratio statistic and its profile counterpart asymptotically follow central chi-square distributions when evaluated at the true parameter. The theoretical properties and practical performance of our approach are demonstrated through numerical simulations and data analysis. Copyright 2012, Oxford University Press.
Electron barrier study of mid-wave infrared interband cascade photodetectors

In this paper, we report our experimental investigation on the influence of electron barrier (eB) in mid-infrared interband cascade photodetectors. Even though earlier theoretical projection indicates that an eB with 2-pairs GaSb/AlSb quantum wells (QWs) is sufficient to block electrons direct tunneling between stages, our experimental results show that a thicker (with 6-pairs of GaSb/AlSb QWs) electron barrier could significantly reduce the device dark current, with little influence on the optical performance. The 5-stage devices have demonstrated a dark current density of 1.10 × 10−7 A/cm2 (at −5 mV) and a Johnson-limited D* of 1.81 × 1011 cmHz1/2/W (at 3.8 μm) at 150 K, respectively.
Hubble Space Telescope observations of X-ray-selected active galactic nuclei

We report on the initial results of a comprehensive Hubble Space Telescope (HST) snapshot imaging survey of 76 low-redshift (z<0.15) X-ray-selected active galactic nuclei (AGN) in the Einstein Extended Medium Sensitivity Survey. This survey is expected to show no bias with respect to host galaxy types, and so is arguably one of the best available samples with HST imaging for the study of the host galaxies. The HST observations in the F814W band are complemented by deeper ground-based observations in the B and R bands for most AGN. The absolute magnitudes for AGN in this sample lie in the range −24<MB(AB)<−18, bracketing the extrapolated break in the QSO luminosity function MB(AB)=−22.3] at these low redshifts. We find a weak correlation between the luminosity of the host galaxy and the central AGN. We find no convincing cases of an AGN with no detectable host galaxy, although the faintest host galaxies of moderately luminous AGN do extend as faint as MB(AB)=−18. We find no evidence for strong interaction/merger activity in any of the AGN in this sample. The median ratio of AGN to host galaxy luminosity (LAGNLHost=0.2) is lower than previously observed, although the observed scatter is large. Approximately 55 per cent of these radio-quiet AGN have host galaxies that are fitted best by a ‘bulge-only’ model (or alternatively are classified visually as ellipticals/S0 galaxies), confirming the result by McLure et al. that radio-quiet AGN are not exclusively found in spiral galaxies. A comparison with the Autofib field galaxy survey shows that the morphological type distribution is skewed toward earlier types than a field galaxy sample drawn at random with the same distribution of luminosities. This is consistent with the observation that the luminosity of the host galaxies is higher by 0.75±0.25 mag than a matching sample drawn from the Autofib survey. Given the bias toward early-type galaxies, the AGN host galaxies are consistent with a luminosity and size distribution identical to normal galaxies. In every respect these galaxies are intermediate in their properties between the large, luminous host galaxies found around high-luminosity AGN in the local Universe and the fainter host galaxies identified around lower luminosity Seyfert galaxies. These results suggest that, with the exception of a bias toward early spectral types, host galaxies of AGN are drawn at random from the overall galaxy population, with the nuclear properties governed (weakly) by spheroid mass.
High-temperature shrinkage of single-walled carbon nanotube bundles up to 1600 K

An experimental study of x-ray diffraction of single-walled carbon nanotube (SWNT) bundles in the temperature range from 290 to 1600 K is reported. The lattice constant (L0) of a close-packed trigonal arrangement of SWNTs in the bundles shrank over the entire temperature range. The hysteretic temperature dependence of L0 was observed and discussed in terms of desorption of molecules from the bundle surface and of a magnetic phase transition of ferromagnetic metal catalyst particles. The coefficient of volume thermal expansion for the bundles is suggested to be negative over the measured temperature range by assuming that the tube-axis expansion is similar to the in-plane expansion for graphite.
Waveguide couplers induced optically over organic junction

A new kind of waveguide and waveguide coupler formed in a nematic liquid crystal (lc) cell is created by means of a weak-intensity laser beam that propagates along the flat boundary between layers of lc and photoconductive polymer. To obtain a waveguide, the connection between the lc and polymer must be driven by the properly polarized voltage. The examined lc cells were of a common kind with indium-tin-oxide (ITO) uniform electrodes on both inner sides of a glass plate. The planar homogeneous alignment of the lc layer was confined by a poly (N-vinyl carbazole) (PVC) layer on one side and a polyimide layer on the opposite side. We applied the PVC doped with a photosensitizer as the photoconductive polymer and a nematic lc mixture of high birefringence. A waveguide was created along a light beam propagation path, and coupling between the waveguides was fabricated in the same way. The energy transfer between the waveguides was proved in properly prepared experiments for laser beam wavelengths equal to 532 nm and 632.8 nm. For both wavelengths, the outcomes of the experiments were of the same quality.
COMMON FIXED POINT THEOREMS FOR RATIONAL TYPE CONTRACTION IN PARTIALLY ORDERED METRIC SPACE

In this paper we prove some common fixed point theorems for two and four self-mappings using rational type contraction and some newly notified definitions in partially ordered metric space. In this way we generalized, modify, and extend some recent results due to Chandok and Dinu [14], Shantanwi and Postolache[28] and many others [1, 2, 4, 5, 21, 29, 30], thus generalizing results of Cabrea, Harjani and Sadarangani [12] as well as Dass and Gupta [15] in the context of partial order metric setting.
Controls on Rayleigh wave amplitudes: attenuation and focusing

A large data set of amplitude measurements of minor and major arc Rayleigh waves in the period range 73–171 s is collected. By comparing these amplitudes with the amplitudes of synthetic waveforms calculated by mode summation, maps of lateral variations in the apparent attenuation structure of the Earth are constructed. An existing formalism for predicting the effects of focusing is employed to calculate amplitude perturbations for the same data set. These perturbations are used to construct ‘pseudo-attenuation’ maps and these results are compared with the apparent attenuation maps calculated from the data. It is shown that variations in Rayleigh wave amplitude perturbations in the Earth are dominated by attenuation at long wavelengths (below about degree 8) and by elastic structure at shorter wavelengths. It is also shown that the linear approximation for focusing is successful at predicting Rayleigh wave amplitudes using existing phase velocity maps. These results indicate that future attempts to model the velocity structure of the Earth would be assisted by incorporating amplitude data and by jointly inverting for Q structure.
Regularity of affine processes on general state spaces

We consider a stochastically continuous, affine Markov process in the sense of Duffie, Filipovic and Schachermayer, with cadlag paths, on a general state space D, i.e. an arbitrary Borel subset of $R^d$. We show that such a process is always regular, meaning that its Fourier-Laplace transform is differentiable in time, with derivatives that are continuous in the transform variable. As a consequence, we show that generalized Riccati equations and Levy-Khintchine parameters for the process can be derived, as in the case of $D = R_+^m \times R^n$ studied in Duffie, Filipovic and Schachermayer (2003). Moreover, we show that when the killing rate is zero, the affine process is a semi -martingale with absolutely continuous characteristics up to its time of explosion. Our results generalize the results of Keller-Ressel, Schachermayer and Teichmann (2011) for the state space $R_+^m \times R^n$ and provide a new probabilistic approach to regularity.
Solar wind electrons: Parametric constraints

Solar wind electrons are often observed to consist of two distinguishable components, a thermal, more dense core and a suprathermal, less dense halo. In this core/halo model linear Vlasov theory for the whistler heat flux instability predicts dimensionless heat flux thresholds which decrease as the electron core beta, , increases. It has been proposed that this theoretical threshold corresponds to an observable upper bound on the electron heat flux. Linear theory also predicts that there is a critical value of below which the whistler heat flux instability does not have appreciable growth in the solar wind; there is another suggestion that this corresponds to an observable lower bound on . These two proposals are examined by comparison of linear theory and data from the initial in-ecliptic phase of the Ulysses mission. The instability threshold does provide a statistical constraint on observed solar wind heat fluxes, and the critical of theory is not inconsistent with a statistical lower bound on the observations of that parameter.
The calculation of atomic fields

The theoretical calculation of observable atomic constants is often only possible if the effective electric field inside the atom is known. Some fields have been calculated to fit observed data but for many elements no such fields are available. In the following paper a method is given by which approximate fields can easily be determined for heavy atoms from theoretical considerations alone.