Miracle-dz/UniFAR-FTUs huggingface dataset:
Validation of a web-based atmospheric correction tool for single thermal band instruments

An atmospheric correction tool has been developed on a public access web site for the thermal band of the Landsat-5 and Landsat-7 sensors. The Atmospheric Correction Parameter Calculator uses the National Centers for Environmental Prediction (NCEP) modeled atmospheric global profiles interpolated to a particular date, time and location as input. Using MODTRAN radiative transfer code and a suite of integration algorithms, the site-specific atmospheric transmission, and upwelling and downwelling radiances are derived. These calculated parameters can be applied to single band thermal imagery from Landsat-5 Thematic Mapper (TM) or Landsat-7 Enhanced Thematic Mapper Plus (ETM+) to infer an at-surface kinetic temperature for every pixel in the scene. The derivation of the correction parameters is similar to the methods used by the independent Landsat calibration validation teams at NASA/Jet Propulsion Laboratory and at Rochester Institute of Technology. This paper presents a validation of the Atmospheric Correction Parameter Calculator by comparing the top-of-atmosphere temperatures predicted by the two teams to those predicted by the Calculator. Initial comparisons between the predicted temperatures showed a systematic error of greater then 1.5K in the Calculator results. Modifications to the software have reduced the bias to less then 0.5 ± 0.8K. Though not expected to perform quite as well globally, the tool provides a single integrated method of calculating atmospheric transmission and upwelling and downwelling radiances that have historically been difficult to derive. Even with the uncertainties in the NCEP model, it is expected that the Calculator should predict atmospheric parameters that allow apparent surface temperatures to be derived within ±2K globally, where the surface emissivity is known and the atmosphere is relatively clear. The Calculator is available at http://atmcorr.gsfc. nasa.gov.
Note on the Stochastic Theory of Resonance Absorption

The stochastic theory of magnetic resonance absorption developed recently by P. W. Anderson is examined here further in some details. The fundamental idea of the theory is that the resonating units suffer transitions among their possible states each of which is characterized by a proper frequency of the magnetic moment. The transition is assumed to be described by a Markoffian process. The fundamental equation for the auto-moment or the auto-correlation of the magnetic moment is rederived and transformed. Some general properties of the absorption spectrum are discussed on the basis of this equation. In particular, the narrowed spectrum for the case of rapid transition is proved to be Lorentzian with a half width determined by the equilibrium distribution of the units and the transition matrix of the Markoffian jumps. If the relaxation time of the transition is assumed to be completely degenerate, the resonance spectrum is given by [Formula: see text] where P (ω) is the intensity distribution in the limit .
Effect of Parameter Variations on the Effectiveness of HQSAR Analyses

HQSAR is a new method for generating alignment-free quantitative structure-activity relationships. Experiments with four different datasets suggest that the variations in PLS scores that are observed with short hologram lengths can be substantially removed either by taking the mean or median of the crossvalidation scores or by using very long holograms. However, because the hashing process unnecessarily obfuscates PLS regression modelling, we suggest that PLS should preferentially be applied to unhashed fragment bit-strings where computationally feasible. The predictive ability of the method is also affected by the size of the fragments that are used, although this effect appears to be dataset-dependent. Variations in the type, rather than the size, of the fragments utilised can also have a significant effect on both internal and external predictivity scores.
Optical study of elastic second-harmonic generation

A detailed theoretical analysis of the problem of elastic second-harmonic generation (SHG) by longitudinal ultrasonic beams of finite dimension propagating in isotroplc media or along certain pure mode axes in crystals has been made. A formulation for optical SHG by Gaussian laser beams, adapted to the ultrasonic case, has allowed calculation of the intensity profile and angular intensity distribution of the second-harmonic beam as a function of distance from the generating fundamental frequency transducer. These calculations were confirmed experimentally, using the beam probing techniques of Bragg diffraction, for both focused and unfocused longitudinal beams, in the frequency range 200-500 MHz, propagating along the Z axis in crystal quartz. Ultrasonic diffraction of the fundamental beam is shown to result in reduction of second-harmonic intensity compared to the intensity normally calculated from plane-wave theory. Consideration of this reduction allowed an accurate value of the third-order elastic constant c 333 to be determined from the measured second-harmonic intensity. The effect of reflection at a crystal-air interface on SHG has also been investigated.
Approximations for the distribution of a maximal pairwise t in some repeated measure designs

A one factor design is considered where each of the experimental units is repeatedly measured under the same set of various factor levels. A simultaneous procedure is con¬sidered based on the maximal Student-t statistic for all pairwise comparisons. The goal of this work is to investigate the possibility of obtaining simple approximations of the quantiles of that statistic without any assumptions on the variance matrix of the estimated effects. Two approximations are considered which are more radical than the Bonferroni method. The results of our simulations clearly indicate that one of these two approximations does not control the family-wise error rate. The other approximation can not be rejected on such grounds. In fact, on extending a conjecture due to Tukey (1953) (and which is known to be true for some special cases) the second approximation will control the required error rate (if the generalized conjecture was true). Finally, the required critical points for the 'extended Tukey' procedure are show.
A multistatic and multifrequency novel approach for specular meteor radars to improve wind measurements in the MLT region

Specular meteor radars (SMRs) have become a widely used tool to observe horizontal winds at the mesosphere and lower thermosphere (MLT). Typically 30 to 120 min mean winds are obtained assuming horizontal homogeneity of the observed area (i.e., few hundreds of kilometer radius). The quality of the measured wind velocity vector depends on the number of detected meteors per altitude and time bins. In order to improve the wind measurements of typical SMRs, here we propose a multistatic and multifrequency approach that consists mainly on adding GPS synchronized receiving stations with interferometric capabilities to existing SMRs. Compared to typical SMRs operating in a monostatic mode, our new approach called MMARIA (Multistatic and Multifrequency Agile Radar for Investigations of the Atmosphere) allows us to (a) increase the number of meteors using the same transmitter (by more than 70%), (b) increase the altitudinal coverage by 5–10 km higher depending on the geometry used, and (c) derive the horizontal wind field in the observed volume by relaxing the assumption of homogeneity. The latter result is facilitated by having common volume observations from at least two different viewing angles. We show the feasibility of these three goals from measurements at two different frequencies using a MMARIA configuration between Juliusruh and Kühlungsborn in northern Germany.
Higher order weak linearizations of stochastically driven nonlinear oscillators

We present derivative-free weak and strong solutions of stochastically driven nonlinear oscillators of engineering interest using higher order forms of the locally transversal linearization (LTL) method. Unlike strong solutions, weak stochastic solutions attempt to predict only mathematical expectations of functions of the true solution and are obtainable with much less computational effort. The linearized equations corresponding to the higher order implicit LTL schemes are arrived at using backward Euler–Maruyama and Newmark expansions in order to conditionally replace nonlinear drift and multiplicative diffusion vector fields. We also briefly describe alterations through which explicit forms of such higher order linearizations are obtained. In the weak forms, the Gaussian stochastic integrals, appearing in the linearized solutions, are replaced by random variables with simpler and discrete probability distributions. The resulting local approximations to the true solution are of significantly higher formal order of accuracy, as reflected through local error estimates. Numerical illustrations are presently provided for the Duffing and Van der Pol oscillators driven by additive and multiplicative noises, which are indicative of the numerical accuracy, computational speed and algorithmic simplicity.
Confidence Intervals for Autocorrelations Based on Cyclic Samples

Abstract Clinger and Van Ness have shown how to sample a stochastic process in a periodic manner such that the autocorrelation function for that process can be estimated at all lags. We derive approximate confidence intervals for these estimates, focusing on low-order autoregressive moving average processes. Our methods are illustrated with an example from plant disease epidemiology.
Photodissociation regions. II. A model for the Orion photodissociation region.

On a construit un modele pour la region de photodissociation d'Orion. Il permet de rendre compte de l'emission observee dans les raies de structure fine de O I a 63 μm et a 145 μm, de C I a 609 μm et C II a 158 μm et des raies rotationnelles de CO. Il explique egalement l'emission H 2 1-0 S(1) etendue, les raies de recombinaison du carbone et la raie C I 9850 A
A Simple Proof of a Result of Kesten and Stigum on Supercritical Multitype Galton-Watson Branching Process

that Znpfn converges almost surely (a.s.) to uW and (ii) P(W = 0) < 1 if and only if E(Z,j logZ,| I = ei) < oc for all i and j where ei = (il, 3i2, ', 3ip), 3ij = 1 if i = j and 0 if i : j, Z,i is thejth coordinate of Z1. We give here a simple proof of a modified result which is exactly the same as above except that convergence a.s. is replaced by convergence in probability. We do this by showing that without any extra assumption other than the existence of M the vector (v * Zn) - 'Zn converges in probability to u on the set of non-extinction.
Phase correlation based redundancy removal in feature weighting band selection for hyperspectral images

Feature weighting based band selection provides a computationally undemanding approach to reduce the number of hyperspectral bands in order to decrease the computational requirements for processing large hyperspectral data sets. In a recent feature weighting based band selection method, a pair‐wise separability criterion and matrix coefficients analysis are used to assign weights to original bands, after which bands identified to be redundant using cross correlation are removed, as it is noted that feature weighting itself does not consider spectral correlation. In the present work, it is proposed to use phase correlation instead of conventional cross correlation to remove redundant bands in the last step of feature weighting based hyperspectral band selection. Support Vector Machine (SVM) based classification of hyperspectral data with a reduced number of bands is used to evaluate the classification accuracy obtained with the proposed approach, and it is shown that feature weighting band selection with the proposed phase correlation based redundant band removal method provides increased classification accuracy compared to feature weighting band selection with conventional cross correlation based redundant band removal.
A Fuzzy Logic Approach for Car-Following Modelling

In this communication, the classical car-following theory, which is based on intuitiveness and behavioural representation, is revisited from the point of view of cybernetics theory. Then, a new approach, based on fuzzy modelling, is proposed to estimate the main parameters of the basic car following model. This approach, contrarily to earlier fuzzy logic approaches, maintains the structure of the classical car-following model, limits its complexity and provides means to take into account the main parameters influencing the behaviour of the driver and allows a formal verification of local and global stability of the simulated traffic flow. So, after introducing a new approach based on cybernetics concepts for the modelling of car-following, which provides a theoretical basis for the basic model, the main concepts of fuzzy logic theory and of fuzzy modelling are briefly presented. Then a fuzzy estimation approach is proposed for the main parameters of the basic car-following model. Finally, simulation results making use of the proposed modelling approach are presented.
Effect of random defects on the critical behaviour of Ising models

A cumulant expansion is used to calculate the transition temperature of Ising models with random-bond defects. For a concentration, x, of missing interactions in the simple-square Ising model the author finds -Tc-1 dTc/dx mod x=0=1.329 compared with the mean-field value of one. If the interactions are independent random variable with a width delta J/J identical to epsilon , the result is -Tc-1 dTc/d epsilon 2 mod epsilon =0=0.312 compared with the mean-field results of zero. An approximation yields the specific heat in the critical regime as C approximately C0/(1+x gamma 2C0), where gamma is a constant and C0 is the unperturbed specific heat at a renormalized temperature. Thus, the specific heat divergence is broadened over a temperature interval Delta T, with Delta T/Tc approximately x(1 alpha )/, where alpha is the critical exponent for the specific heat, and a maximum value of order x-1 is attained. Heuristic arguments show that this smoothing effect occurs if alpha >0.
Experimental ensemble forecasts of precipitation based on a convection‐resolving model

We present the idea and the very first results of an “Experimental ensemble based on the COSMO‐DE (EELMK)”. The aim is to understand predictability limits of precipitation forecasts on the convective scale. Ensemble techniques with convection‐resolving models are a new field of research. We investigate forecast uncertainties due to imperfect model physics and lateral boundary conditions. The initial case studies demonstrate the potential of EELMK to generate variability between ensemble members in terms of spatial homogeneity and intensity of precipitation. Copyright © 2008 Royal Meteorological Society
Minimal energy control of a biped robot with numerical methods and a recursive symbolic dynamic model

The problem of constructing a nonlinear controller for a biped robot optimal with respect to a minimal energy performance criteria is considered. The solution of this difficult, highly nonlinear problem is facilitated by the conjunction of several new developments in numerical optimal control and constrained recursive dynamic models for robotic systems. A 5-link biped model is used with the full dynamics and a uniform distribution of mass at each link. Contacts are modeled as inelastic, and the full dynamics together with the contact and collision forces are calculated efficiently using a recursive symbolic representation of the dynamics. The flexibility and modularity of our dynamics algorithms allows one to construct reduced unconstrained models which do not suffer from integration difficulties. The numerical optimal control software used is powerful and quick enough to handle high dimensional nonlinear systems. The result of our experiment is a walking controller which is optimal with respect to a type of minimum energy performance.
Linear Least-Squares Optimization for Point-to-Plane ICP Surface Registration

The Iterative Closest Point (ICP) algorithm that uses the point-toplane error metric has been shown to converge much faster than one that uses the point-to-point error metric. At each iteration of the ICP algorithm, the change of relative pose that gives the minimal point-to-plane error is usually solved using standard nonlinear least-squares methods, which are often very slow. Fortunately, when the relative orientation between the two input surfaces is small, we can approximate the nonlinear optimization problem with a linear least-squares one that can be solved more efficiently. We detail the derivation of a linear system whose least-squares solution is a good approximation to that obtained from a nonlinear optimization.
Transmission profile of a Fabry-Perot interferometer suffering from asymmetric surface defects

A study has been made of the transmission characteristics of a Fabry-Perot interferometer as modified by the asymmetric surface defects present on the plates. Asymmetric line profiles can be obtained if the error in the plates is not symmetrically distributed about the mean planes of the plates. Peak irradiance and shift of fringe from its integral order position have been tabulated. Such investigations are of interest in a number of problems in high resolution spectroscopy.
Two dimensional LDA using volume measure in face recognition

The classification criterion for the two dimensional LDA (2DLDA)-based face recognition methods has been little considered, while we almost pay all attention to the 2DLDA-based feature extraction. The typical classification measure used in 2DLDA-based face recognition is the sum of the Euclidean distance between two feature vectors in feature matrix, called traditional distance measure (TDM). However, this classification criterion does not match the high dimensional geometry space theory. So we apply the volume measure (VM), which is based on the high dimensional geometry theory, to the 2DLDA-based face recognition in this paper. To test its performance, experiments were performed on the YALE face databases. The experimental results show the volume measure (VM) is more efficient than the TDM in 2DLDA-based face recognition.
Wavelet Analysis of Flow-Induced Forces on Two Side-by-Side Stationary Cylinders: Reynolds Number Effect

In the present study, the effect of Reynolds number (Re) on flow interference between two side-by-side stationary cylinders and the associated flow-induced forces are investigated using a finite element method. The pitch ratio chosen is T/D = 1.7, and Re is varied within the range of laminar flow regime, i.e., 60 < Re < 200. The method of continuous wavelet transform is used to analyze flow-induced forces, especially their time-variant features. Flow patterns in the form of vorticity plot are presented to demonstrate the underlying physics. It is found that flow interference initially occurs in the inner vortices shed from the two cylinders, and extends to the outer vortices with increment of Re. The flow behind two cylinders undergoes three regimes: Regime I - unbiased gap flow, Regime II - stable biased gap flow, and Regime III - unstable gap flow. Flow-induced forces show significant variations when the flow transits from one regime to another. In particular, during the transition from Regime II to III, the forces not only increase by amplitude, but also change their nature from deterministic to random, and show some non-stationary features. This is shown to be caused by the amalgamation of inner and outer vortices behind the two cylinders when the flow interference extends from inner vortices to outer vortices. Whenever possible, the present results are compared with experimental measurements and theoretical predictions. The numerical simulations are consistent with these other results.Copyright © 2006 by ASME
Low-Dislocation-Density GaN from a Single Growth on a Textured Substrate

The density of threading dislocations (TD) in GaN grown directly on flat sapphire substrates is typically greater than 10{sup 9}/cm{sup 2}. Such high dislocation densities degrade both the electronic and photonic properties of the material. The density of dislocations can be decreased by orders of magnitude using cantilever epitaxy (CE), which employs prepatterned sapphire substrates to provide reduced-dimension mesa regions for nucleation and etched trenches between them for suspended lateral growth of GaN or AlGaN. The substrate is prepatterned with narrow lines and etched to a depth that permits coalescence of laterally growing III-N nucleated on the mesa surfaces before vertical growth fills the etched trench. Low dislocation densities typical of epitaxial lateral overgrowth (ELO) are obtained in the cantilever regions and the TD density is also reduced up to 1 micrometer from the edge of the support regions.
Scaling laws for electron cold injection in the narrow collision pulse approximation

The latest advances in laser wakefield electron acceleration show a better beam quality, but much progress is still needed concerning the control and tunability of the electron beam. The recently proposed cold injection scheme offers a solution to this problem. It involves the use of two counter-propagating laser pulses to dephase a certain number of electrons into the wakefield of the main pulse, so that they are accelerated to high energies. As circular polarization is used, there is no stochastic heating and the injection process becomes much easier to model. We show that cold injection can be reduced to a one-dimensional problem in the case of a narrow collision pulse. The dephasing process can then be seen as competition between the longitudinal ponderomotive force of the main pulse and the stationary beatwave force arising from collision of the two circularly polarized lasers. This analysis leads to scaling laws for cold injection in the narrow collision pulse approximation and to a condition for its realization. Three-dimensional particle-in-cell simulations support both these scaling laws and the condition for cold injection to occur.
Sensorless PMSM drive with a sliding mode control based an adaptive speed and a rotor resistance estimator

This paper presents a new speed and position sensorless control method of permanent magnet synchronous motors based on the sliding mode observer. The sliding mode observer structure and its design method are described. Also, Lyapunov functions are chosen for determining the adaptive law for the speed and the stator resistance estimator. The effectiveness of the proposed observer is confirmed by experimental results.
Exact solutions for a class of nonlinear free surface flows

We consider a class of inviscid free surface flows where the free surface is of finite length and in which the pressure on the free boundary pb is different from the free stream pressure p∞. The aim of the paper is to determine the shape of the free surface as a function of the velocity ratio parameter λ. The free boundary problem is tackled by seeking a mapping z ═ f(ζ) such that the flow past a circle in the ζ-plane maps to a flow with constant pressure pb on the free surface in the z-plane. The formulation leads to an infinite system of coupled nonlinear equations for the coefficients in the mapping function. Remarkably, the system can be solved exactly to yield two families of free surface flows of the form z ═ ζ + λ2/ζ + a(λ) ln (ζ + b(λ)/ζ ─ b(λ)). The nature of the solutions, their limitations and possible extensions to them are discussed.
Polynomial Spline Approach for Double Integrals with Algebraic Singularity

In this note, cubature formulas are constructed to evaluate the double integrals on the rectangle with algebraic singularity by replacing the density function f(x,y) with the SΔ(P) modified spline function interpolation of type (0,2). Rate of convergence are obtained in the classes of function f(x,y) ∊ C2,α(D).