Miracle-dz/UniFAR-FTUs huggingface dataset:
Statistical assessment of model fit for synthetic aperture radar data

Parametric approaches to problems of inference from observed data often rely on assumed probabilistic models for the data which may be based on knowledge of the physics of the data acquisition. Given a rich enough collection of sample data, the validity of those assumed models can be assessed in a statistical hypothesis testing framework using any of a number of goodness-of-fit tests developed over the last hundred years for this purpose. Such assessments can be used both to compare alternate models for observed data and to help determine the conditions under which a given model breaks down. We apply three such methods, the (chi) 2 test of Karl Pearson, Kolmogorov's goodness-of-fit test, and the D'Agostino-Pearson test for normality, to quantify how well the data fit various models for synthetic aperture radar (SAR) images. The results of these tests are used to compare a conditionally Gaussian model for complex-valued SAR pixel values, a conditionally log-normal model for SAR pixel magnitudes, and a conditionally normal model for SAR pixel quarter-power values. Sample data for these tests are drawn from the publicly released MSTAR dataset.
Restricted EM algorithm with application to probit models

The EM algorithm is a widely used technique for finding maximum likelihood (ML) estimates when the data are not fully observed. Despite its popularity for computing ML estimates in unrestricted problems and the need for simplified computations for problems with equality and inequality restrictions, there have been few applications of the algorithm to restricted ML estimation. The EM algorithm is presented for restricted ML estimation and provides its applications to the probit model under equality and inequality restrictions using two small data sets.
Emission probability of hot electrons from silicon into silicon dioxide

An experimental method is described for directly measuring the probability of electron emission from the silicon substrate into the SiO2 layer after the electron has fallen through a certain potential drop in traversing the depletion layer and reached the Si‐SiO2 interface. The method is based on optically induced hot‐electron injection in polysilicon‐SiO2‐silicon field‐effect‐transistor structures of reentrant geometry. The emission probability was studied as a function of substrate doping profile, substrate voltage, gate voltage, and lattice temperature. It was found that the hot electrons could be emitted by tunneling as well as by surmounting the Schottky‐lowered barrier. Over‐the‐barrier emission dominates at large substrate voltages, where the emission probability is high, and tunnel emission becomes appreciable and may even dominate at small substrate voltages where the emission probability is low. A simple model was developed based on the assumption that only those hot electrons lucky enough to escape collision with optical phonons were emitted. Using this model, we found that the expression P=A exp(−d/λ) described very well the dependence of the emission probability on doping profile, substrate voltage, and gate voltage. Here A=2.9 is a constant, λ is the optical‐phonon‐electron collision mean free path, d is the distance from the Si‐SiO2 interface where the potential energy is equal to the ’’corrected’’ barrier of (3.1 eV−βEOX1/2 −αEOX2/3ox), βEOX1/2 is the Schottky lowering of the barrier, and αEOX2/3 is a ’’barrier‐lowering’’ term introduced to account for the probability of tunneling. The temperature dependence of the collision mean free path was found to follow the theoretical relationship λ=λo tanh(ER/2kbT), with λo=108 A and ER=0.63 eV. This model is useful for evaluating potential hot‐electron‐related instability problems in IGFET and similar structures.An experimental method is described for directly measuring the probability of electron emission from the silicon substrate into the SiO2 layer after the electron has fallen through a certain potential drop in traversing the depletion layer and reached the Si‐SiO2 interface. The method is based on optically induced hot‐electron injection in polysilicon‐SiO2‐silicon field‐effect‐transistor structures of reentrant geometry. The emission probability was studied as a function of substrate doping profile, substrate voltage, gate voltage, and lattice temperature. It was found that the hot electrons could be emitted by tunneling as well as by surmounting the Schottky‐lowered barrier. Over‐the‐barrier emission dominates at large substrate voltages, where the emission probability is high, and tunnel emission becomes appreciable and may even dominate at small substrate voltages where the emission probability is low. A simple model was developed based on the assumption that only those hot electrons lucky enough to es.
Box/peanut and bar structures in edge-on and face-on nearby galaxies in the Sloan Digital Sky Survey - I. Catalogue

We investigate Box/Peanut and bar structures in image data of edge-on and face-on nearby galaxies taken from SDSS (Sloan Digital Sky Survey) to present catalogues containing the surface brightness parameters and the morphology classification. About 1700 edge-on galaxies and 2600 face-on galaxies are selected from SDSS DR7 in g, r and i-band. The images of each galaxy are fitted with the model of 2-dimensional surface brightness of S\'{e}rsic bulge and exponential disk. After removing some irregular data, Box/Peanut, bar and other structures are easily distinguished by eye using residual (observed minus model) images. We find 292 Box/Peanut structures in the 1329 edge-on samples and 630 bar structures in 1890 face-on samples in i-band, after removing some irregular data. Then the fraction of Box/Peanut galaxies is about 22 percent against the edge-on samples, and that of bar is about 33 percent (about 50 percent if 629 elliptical galaxies are removed) against the face-on samples. Furthermore the strengths of the Box/Peanut and bar are evaluated as "Strong", "Standard" and "Weak". We find that the strength increases slightly with increasing $B/T$ (Bulge-to-Total flux ratio), and that the fraction of Box/Peanut is generally about a half of that of bar irrespective of the strength and the $B/T$. Our result supports the idea that the Box/Peanut is bar seen edge-on.
Nature of the process of overdriven shocks in metals

Within the bounds established by the formal theory of overdriven shocks in solids, an approximate solution is constructed, and a consistent set of approximations for the thermodynamic coefficients is described. Numerical calculations of the temperature, entropy, shear stress, and plastic strain, as functions of compression, are shown for shocks up to 0.8 Mbar in 2024 Al, and up to 3.0 Mbar in Pt. For well-overdriven shocks in metals the shock entropy is generated by heat conduction in the front part of the shock, the heat is generated by plastic flow in the last part of the shock, and the shock rise time is of order 10/sup -12/ s.
Highly reflective GaN/Al0.34Ga0.66N quarter-wave reflectors grown by metal organic chemical vapor deposition

Quarter-wave reflectors consisting of sets of GaN and Al0.34Ga0. 66N layers have been grown on sapphire substrates by atmospheric-pressure metal organic chemical vapor deposition. A periodic structure with flat interfaces was observed by high-resolution scanning electron microscopy. X-ray diffraction measurements were performed to characterize the structures, from which the Al content x in the AlxGa1−xN layers was determined to be 0.34. No cracks could be seen on the surface of the reflectors by optical microscopy. The measured peak reflectivity at 390 nm increases with the number of pairs and reaches as high as 96±2% in the 35-pair reflector.
Sputtering-induced vacancy cluster formation on TiO2(110)

Defects are introduced on an atomically clean TiO{sub 2}(110) surface in a controllable manner via bombardment by 0.5 keV Ar{sup +} ions, and the resultant material is probed with scanning tunneling microscopy and x-ray photoelectron spectroscopy. It is shown that ion bombardment leads to a change of stoichiometry and the formation of vacancy clusters, while annealing after prolonged bombardment forms regular rectangular cavities with single-atomic-layer steps. It is concluded that curvature-dependent sputtering in combination with adatom and vacancy diffusion is responsible for the observed structures.
The effect of shock wave compression on double wall carbon nanotubes

Double wall carbon nanotubes (DWCNTs) have proven to have a very good structural stability when exposed to high static pressures. We report here on the study of DWCNTs after application of shock wave (dynamic) compression up to 36 GPa in a recovery assembly. TEM images of so‐treated samples reveal a threshold between 19 and 26 GPa of shock wave compression above which significant structural damage is induced whereas only minor damage can be detected below. The threshold detected with TEM coincides well with the collapse pressure of DWCNTs previously reported [You et al., High Press. Res. 31, 186 (2011); Aguiar et al., Phys. Chem. C 115, 5378 (2011)]. Raman data demonstrate a gradual accumulation of structural defects via an increase in D‐band to G‐band intensity ratio (ID/IG‐ratio) from ∼0.2 to ∼0.8 in going from the source CNT material to the nanotubes after compression to 36 GPa. Despite severe damage; the DWCNTs exposed to 36 GPa of shock wave compression survived which is evidenced by Raman spectra. The DWCNTs demonstrate a higher susceptibility to structural damage under dynamic than static pressure.
Gaussian process framework for pervasive estimation of swimming velocity with body-worn IMU

Presented is an accurate swimming velocity estimation method using an inertial measurement unit (IMU) by employing a simple biomechanical constraint of motion along with Gaussian process regression to deal with sensor inherent errors. Experimental validation shows a velocity RMS error of 9.0 cm/s and high linear correlation when compared with a commercial tethered reference system. The results confirm the practicality of the presented method to estimate swimming velocity using a single low-cost, body-worn IMU.
Counts, evolution, and background contribution of X-ray quasars and other extragalactic X-ray sources

The present study of extragalactic X-ray source characteristics gives attention to quasars and to active galactic nuclei of lower luminosity, especially those presented by Tananbaum et al. (1979). Assuming that the comoving space density of quasars varies with redshift at a rate that depends on luminosity, the number of quasars in the Medium Sensitivity Surveys, as well as their average redshift, can be understood if the X-ray luminosity of quasars of given optical property decreases with increasing redshift. It is estimated that low luminosity active galactic nuclei with M(B) greater than -23 contribute 29 percent of the X-ray background. 47 references.
On the Dynamical Propagation of Subvolumes and on the Geometry and Variational Principles of Nonholonomic Systems.

On the Dynamical Propagation of Subvolumes and on the Geometry and Variational Principles of Nonholonomic Systems by Jared Michael Maruskin Co-Chairs: Anthony M. Bloch and Daniel J. Scheeres Their are two main themes of this thesis. The first is the theory and application of the propagation of subvolumes in dynamical systems. We discuss the integral invariants of Poincaré-Cartan and introduce a new and closely related set of integral invariants, those of Wirtinger type, and relate these new invariants to a minimum obtainable symplectic volume. We will then consider the application of this approach to the orbit determination and correlation problem for tracking particles of space debris. The second theme is on the geometry of nonholonomic systems. In particular we will focus on the precise geometric understanding of quasi-velocity techniques and its relation to the formulation of variational principles for these systems. We will relate the Euler-Poincaré equations for Lie groups to the Boltzmann-Hamel equations and further extend both these equations to a higher order form that is applicable to optimal dynamical control problems on manifolds.
Effective medium approximation and exact formulae for electrokinetic phenomena in porous media

Electrokinetic phenomena in porous media are studied by application of the effective medium theory and the theory of duality transformation. We deduce new exact relations and analytical formulae for the effective constants of the macroscopic tensor. We also prove that the effective tensors obtained by these approaches coincide for 2D problems. The obtained results for the electrokinetic processes are closely related to similar results derived for piezoelectric composites because of a common mathematical background.
Multiperiodicity in Five Small‐Amplitude Pulsating Red Giants

We report multiperiodicity in five small‐amplitude pulsating red giants: RZ Ari, V523 Mon, BC CMi, UX Lyn, and FS Com. For each of these stars, two or three periods recur in each season of our 5000 day database of V observations. The periods and their ratios are consistent with low‐order radial pulsation modes. The amplitudes of the modes change significantly on timescales of 1–5 yr; specifically, the amplitudes of the dominant periods vary on timescales of 2000–3500 days. Most often, the amplitudes of the modes in a given star rise and fall in unison.
Uniform asymptotic solutions of a class of second order linear differential equations having a turning point and a regular singularity, with an application to Lengendre functions

The asymptotic behaviour, as a parameter $u \to \infty $, of solutions of second-order linear differential equations with a turning point and a regular (double pole) singularity is considered. It is shown that the solutions can be approximated by expressions involving Bessel functions in a region which includes both the turning point and the singularity. Explicit error bounds for the difference between the approximations and the exact solutions are established. The theory is applied to find uniform asymptotic expansions for Legendre functions.
Efficient Statistical Transport Model for Turbulent Particle Dispersion in Sprays

A statistical transport model for turbulent particle dispersion is formulated having significantly improved computational efficiency in comparison to the conventional stochastic discrete-particle methodology. In the proposed model, a computational parcel representing a group of physical particles is characterized by a normal (Gaussian) probability density function (pdf) in space. The mean of each pdf is determined by Lagrangian tracking of each computational parcel, either deterministically or stochastically
Magnetic reconnection in an anisotropic plasma: Observation and theory

Space plasma usually exhibits temperature or pressure anisotropy with two distinct components, p∥ and p⊥, denoting the pressure parallel and perpendicular to the magnetic field, respectively. This paper presents the first result of two‐dimensional (∂/∂y = 0) magnetic reconnection with single X‐line in anisotropic plasma based on gyrotropic magnetohydrodynamic (MHD) simulations. The field‐line reconnection is initiated by imposing a localized resistivity on the Harris‐type current sheet with a guide magnetic field By. It is shown that the observational feature of a slow shock (SS) followed by a contact discontinuity (CD) near the central sheet, across which the magnetic field is decreased and the pressure anisotropy is changed from p∥ > p⊥ to p∥ ≈ p⊥, as identified by Hoshino et al. (2000) in the Geotail data, may be reproduced in our simulations. For the initial equilibrium with relatively large pressure anisotropy of p∥ ≫ p⊥, the steady reconnection layer may consist of SS followed by rotational discontinuity (RD) with both upstream and downstream states of SS being super‐Alfvénic which is similar to the anomalous SS‐RD compound structure found in the solar wind and magnetosphere. While for the cases of p⊥ > p∥, the reconnection layer may consist of RD followed by SS and the reconnection rate is larger as compared to the cases of p∥ ≥ p⊥.
Measurement of roughness exponent for scale‐invariant rough surfaces using angle resolved light scattering

It is shown that, by modifying the conventional light scattering geometry, it is possible to characterize the root‐mean‐square roughness w in a scale‐invariant rough surface for w values more than one order of magnitude larger than those previously reported. Measurement of w on the order of the wavelength of light has been demonstrated. A consequence of this development is that one can combine the diffraction theory and the measurement to determine the surface roughness exponent α, which was not possible under conventional light scattering conditions.
System for conveyor belt part picking using structured light and 3D pose estimation

Automatic picking of parts is an important challenge to solve within factory automation, because it can remove tedious manual work and save labor costs. One such application involves parts that arrive with random position and orientation on a conveyor belt. The parts should be picked off the conveyor belt and placed systematically into bins. We describe a system that consists of a structured light instrument for capturing 3D data and robust methods for aligning an input 3D template with a 3D image of the scene. The method uses general and robust pre-processing steps based on geometric primitives that allow the well-known Iterative Closest Point algorithm to converge quickly and robustly to the correct solution. The method has been demonstrated for localization of car parts with random position and orientation. We believe that the method is applicable for a wide range of industrial automation problems where precise localization of 3D objects in a scene is needed.
Probabilistic proof of product formulas for Bessel functions

We write, for geometric index values, a probabilistic proof of the product formula for spherical Bessel functions. Our proof has the merit to carry over without any further effort to Bessel-type hypergeometric functions of one matrix argument. Moreover, the representative probability distribution involved in the matrix setting is shown to be closely related to matrix-variate normal distributions and to the symmetrization of upper-left corners of Haar distributed orthogonal matrices. Once we did, we use the latter relation to perform a detailed analysis of this probability distribution. In case it is absolutely continuous with respect to Lebesgue measure on the space of real symmetric matrices, the product formula for Bessel-type hypergeometric functions of two matrix arguments is obtained from Weyl integration formula.
Design and Fabrication of Interdigital Supercapacitors as Force/Acceleration Sensors

The integrated device for energy supply and sensing (IDESS) is a potential candidate for relieving the energy and space burdens caused by the rising integration degrees of microsystems. In this article, we propose a force sensor based on an interdigital supercapacitor (IDTSC). The capacitance and internal resistance of the IDTSC change under external loads, resulting in a transient current fluctuation at a constant bias voltage, which can be used to sense external force/acceleration. The IDTSC showed a specific energy and specific power of 4.16 Wh/kg and 22.26 W/kg (at 0.1 A/g), respectively, which could maintain an essential energy supply. According to the simulation analysis, the designed IDTSC’s current response exhibited good linearity with the external force. In addition, benefiting from its light weight and the applied gel electrolytes, the IDTSC showed good high-g impact sensing performance (from 9.9 × 103× g to 3.2 × 104× g). This work demonstrated the feasibility of realizing an integrated energy supply and force-sensing device by empowering energy storage devices with sensing capabilities.
Efficient coding explains neural response homeostasis and stimulus-specific adaptation

Neurons are typically sensitive to a small fraction of stimulus space. If the environment changes, making certain stimuli more prevalent, neurons sensitive to those stimuli would respond more often and therefore, if the stimulus-response mapping remains fixed, have a higher average firing rate. However, sufficiently prolonged exposure to the new environment typically causes such neurons to adapt by responding less vigorously. If adaptation consistently returns the average firing rate of neurons, or populations of similarly tuned neurons, to its value prior to environmental shift, it is termed firing rate homeostasis. In sensory cortex adaptation is typically also stimulus specific, with neurons maintaining or even increasing their responsiveness to stimuli far from over-represented ones. Here, we present a normative explanation of firing rate homeostasis grounded in the efficient coding principle. Unlike previous theories based on efficient coding, we formulate the problem in a computation-agnostic manner, enabling our framework to apply far from the sensory periphery. We show that homeostasis can provide an optimal solution to a trade-off between coding fidelity and the metabolic cost of neural firing. We provide quantitative conditions necessary for the optimality of firing rate homeostasis, and predict how adaptation should deviate from homeostasis when these conditions are violated. Based on biological estimates of relevant parameters, we show that these conditions do hold in areas of cortex where homeostatic adaptation has been observed. Finally, we apply our framework to distributed distributional codes, a specific computational theory of neural representations serving Bayesian inference. We show that the resultant coding scheme can be accomplished by divisive normalisation with adaptive weights. We further demonstrate how homeostatic coding, coupled with such Bayesian neural representations, explains stimulus-specific adaptation, as observed, e.g., in the primary visual cortex.
Algebraic Properties of Monomial Ideals

In this thesis we first study a special class of squarefree monomial ideals, namely, path ideals. We give a formula to compute all graded Betti numbers of the path ideal of a cycle and a path. As a consequence we can give new and short proofs for the known formulas of regularity and projective dimensions of path ideals of path graphs and cycles. We also study the Rees algebra of squarefree monomial ideals. In 1995 Villarreal gave a combinatorial description of the equations of Rees algebras of quadratic squarefree monomial ideals. His description was based on the concept of closed even walks in a graph. In this thesis we will generalize his results to all squarefree monomial ideals by using a definition of even walks in a simplicial complex. We show that simplicial complexes with no even walks have facet ideals that are of linear type, generalizing Villarreal’s work.
A climatology of mesoscale convective systems over Europe using satellite infrared imagery. II: Characteristics of European mesoscale convective systems

An automated method for mesoscale convective system (MCS) identification and tracking (described in part I) is applied in order to derive a sound European MCS database using Meteosat infrared channel (IR10.8) images centred over Europe, the western Mediterranean and north Africa. The database covers five warm seasons, from April to September, for the years 1993 to 1997 and includes more than 6000 MCSs reaching at least an area of 10 000 km2.