Miracle-dz/UniFAR-FTUs huggingface dataset:
Texture modelling for land cover classification of fully polarimetric SAR images

Classification based on polarimetric data alone does not provide sufficient sensitivity for classes’ separation such as forests. The use of other characteristics such as texture provides a powerful tool to get better class discrimination. Thus, this article outlines an approach for texture modelling adapted to land identification using polarimetric synthetic aperture radar (PolSAR) images. As radar images may contain a myriad of textures and to take into account their non-stationarity feature, the model is non-parametric and is based on a likeness measure between neighbourhoods. This measure is incorporated in probability formulation of the textural model. The latter is validated through texture synthesis applied to Brodatz’ natural textures. While having multiple applications, we focused here on the issue of terrain mapping of PolSAR images. Using Bayesian approach and some basic assumptions, we defined a classification scheme based on the textural model. It was tested on original Pauli decomposed images and filtered ones. The test area used is the Oberpfaffenhofen in Munich and the PolSAR images were acquired in the P band. For evaluation purposes, the classifications results obtained were compared with the Wishart classifier result performed on H–α partition showing interesting results and reaching classification rates ≈90%. Such an analysis has allowed us to assess the importance of texture considering and proved that the proposed texture model is able to describe the target's physical properties of PolSAR data.
Precise orbital and geodetic parameter estimation using SLR observations for ILRS AAC

In this study, we present results of precise orbital geodetic parameter estimation using satellite laser ranging (SLR) observations for the International Laser Ranging Service (ILRS) associate analysis center (AAC). Using normal point observations of LAGEOS-1, LAGEOS-2, ETALON-1, and ETALON-2 in SLR consolidated laser ranging data format, the NASA/GSFC GEODYN II and SOLVE software programs were utilized for precise orbit determination (POD) and finding solutions of a terrestrial reference frame (TRF) and Earth orientation parameters (EOPs). For POD, a weekly-based orbit determination strategy was employed to process SLR observations taken from 20 weeks in 2013. For solutions of TRF and EOPs, loosely constrained scheme was used to integrate POD results of four geodetic SLR satellites. The coordinates of 11 ILRS core sites were determined and daily polar motion and polar motion rates were estimated. The root mean square (RMS) value of post-fit residuals was used for orbit quality assessment, and both the stability of TRF and the precision of EOPs by external comparison were analyzed for verification of our solutions. Results of post-fit residuals show that the RMS of the orbits of LAGEOS-1 and LAGEOS-2 are 1.20 and 1.12 cm, and those of ETALON-1 and ETALON-2 are 1.02 and 1.11 cm, respectively. The stability analysis of TRF shows that the mean value of 3D stability of the coordinates of 11 ILRS core sites is 7.0 mm. An external comparison, with respect to International Earth rotation and Reference systems Service (IERS) 08 C04 results, shows that standard deviations of polar motion and are 0.754 milliarcseconds (mas) and 0.576 mas, respectively. Our results of precise orbital and geodetic parameter estimation are reasonable and help advance research at ILRS AAC.
Poor Returns to Origin-Country Education for Non-Western Immigrants in Italy: An Analysis of Occupational Status on Arrival and Mobility

Previous research on the Italian case has shown that non-Western immigrants are very likely to hold low-qualified jobs and that their occupational mobility chances are rather poor, which suggests low returns to education. In this paper, we investigate whether, and to what extent, immigrants’ different areas of origin moderate the returns to educational degrees obtained in the origin country. Data from a survey on the immigrant population (carried out in 2011‒2012) are used, and, differently from previous studies, we focus on returns to origin-country education with respect to both the socioeconomic status of the first job found on arrival and the subsequent occupational mobility. The results show that almost all non-Western immigrants experience remarkably low returns to post-secondary education on their first job. Contrary to other West-European countries, those returns in Italy are only slightly different by area of origin, which suggests that differences in the transferability and quality of skills are scarcely relevant in a strongly segmented labour market. Rather, the modes of labour market insertion―e.g., formal search methods or relying on contacts with natives―have a sizeable impact on the returns. Origin-country post-secondary degrees are also consistently associated with low returns on subsequent mobility, although highly educated immigrants from new EU member states experience higher chances of upward mobility. In line with some recent findings, recognition of educational credentials seems decisive for the very few non-Western immigrants who are able either to access better-qualified jobs on arrival or to improve their occupational status over time.
Weighted-loss-function CUSUM chart for monitoring mean and variance of a production process

In a production process, when Statistical Process Control (SPC) deals with a quality characteristic (e.g. a dimension) that is a variable, it is usually necessary to monitor both the mean value of the quality characteristic and its variability. The CUSUM scheme comprising a few cooperative CUSUM charts is quicker than the traditional Shewhart &S charts for this purpose. However, the designs and analyses of such a multi-chart CUSUM scheme are mathematically intractable and the operation is very laborious. Based on the Weighted Loss Function, this article proposes a CUSUM chart (called the WLC chart) that detects both mean shift and variance shift by inspecting a single statistic WL (Weighted Loss Function). The most useful feature of the WLC chart is its simplicity for implementation and design compared with the CUSUM scheme using a few CUSUM charts. This is mainly attributable to the use of a single statistic WL. Moreover, based on the results of a factorial experiment, it is found that the WLC chart is, on average, more effective than the &S charts and the multi-chart CUSUM scheme by about 30 and 14%, respectively. A step-by-step procedure is also presented to facilitate practitioners in designing the WLC chart.
Some Inequalities for Norms of Commutators

Let $A, B$ be positive operators and let $f$ be any operator monotone function. We obtain inequalities for $|||f(A)X - Xf(B)|||$ in terms of $|||f\left(|AX - XB| \right) |||$ for every unitarily invariant norm. The case $X = I$ was considered by T. Ando [Math. Z. , 197 (1988), pp. 403--409], and some of our results reduce to his results in this special case. Some related inequalities are obtained.
Discretization of Integral Equations Describing Flow in Nonprismatic Channels with Uneven Beds

Application of the finite-volume method in one dimension for open channel flow predictions mandates the direct discretization of integral equations for mass conservation and momentum balance. The integral equations include source terms that account for the forces due to changes in bed elevation and channel width, and an exact expression for these source term integrals is presented for the case of a trapezoidal channel cross section whereby the bed elevation, bottom width, and inverse side slope are defined at cell faces and assumed to vary linearly and uniformly within each cell, consistent with a second-order accurate solution. The expressions may be used in the context of any second-order accurate finite-volume scheme with channel properties defined at cell faces, and it is used here in the context of the Monotone Upwind Scheme for Conservation Laws (MUSCL)-Hancock scheme which has been adopted by many researchers. Using these source term expressions, the MUSCL-Hancock scheme is shown to preserve stationarity, accurately converge to the steady state in a frictionless flow test problem, and perform well in field applications without the need for upwinding procedures previously reported in the literature. For most applications, an approximate, point-wise treatment of the bed slope and nonprismatic source terms can be used instead of the exact expression and, in contrast to reports on other finite-volume-based schemes, will not cause unphysical oscillations in the solution.
G-Loops and Permutation Groups☆

Abstract A G -loop is a loop which is isomorphic to all its loop isotopes. We apply some theorems about permutation groups to get information about G -loops. In particular, we study G -loops of order pq , where p q are primes and p ∤ ( q − 1). In the case p = 3, the only G -loop of order 3 q is the group of order 3 q . The notion “ G -loop” splits naturally into “left G -loop” plus “right G -loop. ” There exist non-group right G -loops and left G -loops of order n iff n is composite and n > 5.
Chromatic boundary detection by integrating adaptive smoothing and vector gradient approach

Chromatic boundaries are edges caused by material changes. To detect these boundaries in the color images, chromatic information must be used. In this paper, we present an integration algorithm to combine adaptive smoothing technique and vector gradient approach together. Simulation results show that the integration algorithm earns the benefits of both adaptive smoothing technique and vector gradient approach. It can detect chromatic boundaries effectively and smooth out the variations within chromatic boundaries. Whether input color images are contaminated noise or not, the integration algorithm performs better than both adaptive smoothing for intensity image and vector gradient approach.
Breakdown phenomena in high‐speed dislocations

An analytical solution is presented for the atomic displacements in the steady motion of a dislocation in a modified Frenkel‐Kontorova model of the form treated previously by Atkinson and Cabrera. It is found that at a critical dislocation velocity, here termed the breakdown velocity, ν B, the regular dislocation motion postulated a priori breaks down, so that the analytical solution is not valid for dislocation velocities ν ≥ ν B. Furthermore, ν B is less than the corresponding macroscopic sound velocity for this model. The results of computer‐simulation studies of the behavior of the model at stress levels greater than those which cause dislocation breakdown are also presented.
Demographics/Job Characteristics of Top Managers, Corporate Risk and Organizational Outcomes

espanolEl presente estudio analiza la relacion entre caracteristicas demograficas / laborales de gestores de primer nivel y su tolerancia o aversion al riesgo corporativo. A partir de la base de datos Amadeus - Bureau van Dijk se recopilar datos de 1045 gestores de primera, sobre su genero, edad, antecedentes educativos, dualidad y tiempo de mandato. Los resultados sugieren que los ejecutivos (CEO y no CEO) con formacion en las areas de gestion y derecho, asi como el tiempo de mandato, estan negativamente relacionados con el comportamiento de propension al riesgo. La edad de los gestores de primer nivel y el genero femenino son caracteristicas que estan positivamente relacionadas con la propension al riesgo. portuguesO presente estudo analisa a relacao entre caracteristicas demograficas/laborais de gestores de topo e a sua tolerância ou aversao ao risco corporativo. A partir da base de dados Amadeus – Bureau van Dijk foram recolhidos dados de 1.045 gestores de topo, a respeito de seu genero, idade, background educacional, dualidade e tempo de mandato. Os resultados sugerem que executivos (CEOs e nao CEOs) com formacao nas areas de gestao e direito, bem como o tempo de mandato, estao negativamente relacionados com o comportamento de propensao ao risco. Ja a idade dos gestores de topo e o genero feminino sao caracteristicas que estao positivamente relacionadas com a propensao ao risco. EnglishThis study aims to analyze the relationship between demographics and job characteristics of top managers and their tolerance or aversion to corporate risk. From the Amadeus – Bureau van Dijk database were collected data about the gender, age, educational background, job duality and job tenure of 1,045 top managers. The results suggest that executives (CEOs and non-CEOs) with formal education in the areas of management and law, as well as the tenure in the organization, are negatively related to risk-propensity behaviors. On the other hand, the age and female gender of top managers are characteristics that are positively related to risk propensity.
THE PERCEPTION OF PEARSON PRODUCT MOMENT CORRELATIONS FROM BIVARIATE SCATTERPLOTS

Perceptions about the Pearson product moment correlation, r, from bivariate scatterplots were investigated through the use of a questionnaire. It was found that subjects who are relatively sophisticated in psychometric techniques tend to underestimate the magnitude of r, with most pronounced disparity in the range . 2 < |r| < . 6. Additionally, estimates of r from specially designed scatterplots indicated that subjects (1) correctly estimated the effects of range restriction, (2) underestimated the effects of attenuating outliers, (3) incorrectly reduced estimates of r when the regression slope was relatively high or low, and (4) often failed to consider the effects of removing the middle third of the data. Several implications of these generally conservative estimations are discussed.
On the receptivity of free shear layers to two-dimensional external excitation

In this paper, we study the receptivity of a typical free shear layer to pulse-type and periodic excitation. We do this by solving the initial-value problem completely and studying its long-time behaviour. This leads to a wave packet for the pulse. By the superposition of many wave packets, we generate a spatial instability mode when the flow is convectively unstable. This establishes a general and simple relationship between the receptivities for pulse-type and sinusoidal excitations. We find that a shear layer is very receptive to high-frequency disturbances that are generated near the centreline of the layer.
Interest Rates Close to Zero, Post-crisis Restructuring and Natural Interest Rate

Central banks do not seem to account for the impact of interest rates close to zero on the natural interest rate after the bursting of the asset bubble that triggered the fi nancial crisis in 2008. We claim that this omission may have harmful consequences. Should interest rates close to zero persistently decrease natural interest rates that would mean a fall in TFP growth and more limited central bank's capacity to infl uence aggregated demand and price dynamics. We explain that interest rates close to zero may persistently reduce the natural interest rate because in the economy, requiring post-crisis restructuring, they impede the process of restructuring and facilitate forbearance lending, which crowds viable economic agents out of credit through a number of channels. To reduce these risks, the central bank could voluntarily set a lower bound for interest rates cuts at, for instance, 2%. The boundary appropriate for a given economy should be a function of its growth rate and interest rates in the pre-crisis period. We argue that irrespectively of the central bank’s credibility such a change in the monetary policy conducting in economies requiring post-crisis restructuring would bring better outcomes than keeping interest rates close to zero.
The Distribution of Relaxation Times in Typical Dielectrics

K. W. Wagner's treatment of the distribution of relaxation times in dielectrics is reviewed; the effect of the density of distribution upon the frequency variation of the dielectric constant and dielectric loss factor is discussed; and a graphical method of evaluating the constants of Wagner's equation from experimental data is described. These constants have been evaluated for a number of typical dielectrics, and the frequency variations of the dielectric constant and dielectric loss factor as computed from Wagner's equations and from the simple equations for a single relaxation time are compared with the observed behavior. The quantitative correlation obtained between Wagner's equations and the experimental data investigated is viewed as a confirmation of Wagner's theory of a statistical distribution of relaxation times in dielectrics.
Steady PDEs on generalized rectangles: a change of genericity in mode interactions

Boundary conditions may induce subtle effects on the genericity of bifurcation problems. The group of transformations that leave the domain invariant does not necessarily contain all the symmetries of the problem. We give a detailed description of how this phenomenon occurs for elliptic PDEs (in particular steady reaction-diffusion equations) with Neumann boundary conditions on n-dimensional rectangles. The generic bifurcation equations for mode interactions are given in the appropriate symmetry context. We observe that the form of the equations does not depend on the dimension of the domain. With a suitable interpretation and some extra minor considerations, the classification of Armbruster and Dangelmayr (1987) for the 1-dimensional case applies in n dimensions as well.
Lifetime Measurements in Fluorine and Silicon in the Vacuum Ultraviolet

We have measured radiative lifetimes for 19 excited levels in F I–IV and Si II–IV by the beam–foil technique. The production of silicon beams by the use of SF6 as the source gas is discussed. The lifetime results are compared with theory and experiment where possible, and 7 new experimental lifetimes are presented.
Quantitative analysis of scanning microwave microscopy on dielectric thin film by finite element calculation

Using numerical calculations based on a finite element method, we present a quantitative analysis of the dielectric constant of thin films on thick substrates in order to fit the experimental data measured by a scanning microwave microscope. The shift of the resonance frequency of the probe was calculated for the case of dielectric thin films on LaAlO3 (e=24) and MgO (e=10) substrates and, at the same time, the fitting functions were derived as a function of the tip–sample distance. The experimental data were found to agree well with our fitting functions, rendering our quantitative analysis reasonable. We have also discussed the effect of the anisotropy of dielectric constants.
The North Atlantic Oscillation in the Atlantic‐European SLP*

An analysis of the signature of the North Atlantic Oscillation (NAO) in the Atlantic-European sea level pressure (SLP) is presented for observed (German Weather Service) and ECMWF T21 model data. The former time series consists of 1881–1984 January to December fields and the latter of 42 monthly fields from 3 permanent January simulations. The NAO is shown to be one of the dominant eigenmodes of SLP for all calendar months. A very similar NAO anomaly pattern is filtered from the T21 model data, whereby the correspondence between model and reality is far better than for the mean states. Typical extreme states of the NAO, i.e. high- and low-index situations are reconstructed from the EOF (empirical orthogonal functions) and the mean fields. The annual cycle of these states and the differences between observed and simulated January extremes of the NAO are discussed. DOI: 10.1034/j.1600-0870.1990. t01-3-00001.x
Terrestrial kilometric radiation: The cyclotron theory

We examine the gyroresonance condition to determine which electrons can resonate with a specific electromagnetic wave (given ω and k∥) and find that for each gyroresonance harmonic the resonant electrons lie on an ellipse in v⊥ - v∥ space. The growth rate for a given wave due to a given distribution f of electrons involves an integral around the ‘resonant ellipse. ’ Using a contour plot of f in v⊥ - v∥ space and a set of drawn ellipses, one can identify which waves grow fastest and which electrons contribute to the growth. We find that for ∂f/∂v⊥ > 0 at small v⊥ there always exist rapidly growing waves with k∥²c²/ω² = n²cos²θ ≪ 1. These ideas are applied to the interpretation of the terrestrial kilometric radiation (TKR). The growth rate for x mode radiation is calculated by using observations (from the ESRO 4 spacecraft) of the electron distribution in ‘inverted V’ events. A positive growth rate is found, providing strong support for the cyclotron theory of TKR. The calculated growth rate is smaller than required, but this may be partly a selection effect. It is argued that the specific features in the electron distribution that generate TKR should disappear in much less than a second and hence should not be observable in particle data averaged over more than a second. An analytic calculation of the maximum growth rate compatible with the data is at least an order of magnitude larger than that required to account for TKR. The basic feature in the electron distribution that gives rise to TKR is a one-sided loss-cone anisotropy in which upward-moving electrons with small pitch angles are missing. We speculate that the particular features causing large growth rates might be due to the effects of the parallel electric field.
Growth and characterization of a delta‐function doping layer in Si

We present a procedure whereby a sheet of donor atoms is incorporated in (100) Si during molecular beam epitaxial growth. Analysis by secondary ion mass spectroscopy and transmission electron microscopy shows that the width of such δ‐function doping layers is only a few lattice planes. Tunneling spectroscopy and transport measurements give evidence for quantum confinement of the electronic charge in the layer and thus confirm the narrow width.
Algorithmic statistical process control: concepts and an application

The goal of algorithmic statistical process control is to reduce predictable quality variations using feedback and feedforward techniques and then monitor the complete system to detect and remove unexpected root causes of variation. This methodology seeks to exploit the strengths of both automatic control and statistical process control (SPC), two fields that have developed in relative isolation from one another. Recent experience with the control and monitoring of intrinsic viscosity from a particular General Electric polymerization process has led to a better understanding of how SPC and feedback control can be united into a single system. Building on past work by MacGregor, Box, Astrom, and others, the article covers the application from statistical identification and modeling to implementing feedback control and final SPC monitoring. Operational and technical issues that arose are examined, and a general approach is outlined.