Miracle-dz/UniFAR-FTUs huggingface dataset:
Protostellar formation in rotating interstellar clouds. VIII - Inner core formation

The results are presented of a variety of spherically symmetric one-dimensional (1D) calculations intended to determine the robustness of the dynamical hiccup phenomenon in protostellar cores. The 1D models show that the phenomenon is relatively insensitive to changes in the equations of state, numerical resolution, initial density and temperature, and the radiative transfer approximation. In 1D, the hiccup results in an explosive destruction of the entire inner protostellar core. Inner core formation is studied with a sequence of three-dimensional models which show that rapid inner core rotation stabilizes the hiccup instability. Instead, the inner core becomes quite flat and undergoes a cycle of binary fragmentation, binary decay into a single object surrounded by a bar, breakup of the bar into a binary, etc. When lesser amounts of rotation are involved, the inner core does hiccup somewhat, but mass is ejected in only a few directions, leading to several broad streams of ejecta. 29 refs.
Adaptive hole filling for 3D warping-based virtual view synthesis

In this paper, we discuss a Free viewpoint synthesis with View + Depth format for Multiview applications such as 3DTV and Free View-point Television(FTV)1.When generating a virtual image, 3D warping is used with view and depth of a reference camera. This process includes the problem that holes appear in the virtual image. In conventional method, the holes were dealt with collectively by median filter. There are some different reasons why holes appear through this process. So, it is improper that they are not distinguished particularly and treated all at once like conventional method. We analyze the factors, and recognize that two ones exist, boundary between foreground and background, and reduction of resolution. In this paper, we propose a new hole filling method considering these factors. In the first step, we classify nearby pixels into boundary or same object area according to the gradient of depth value. For boundary case, we hold them and refer to other two real cameras. For another case of same object area, we set up sub-pixels between nearby pixels and warp them if the depth is gradually changing or virtual viewpoint of the warped image is closer to the object than the original view position because they probably cause holes from reduction of resolution. We implement these methods in the simulation. As a result, we prevent boundary in the virtual image from being ambiguous, and confirm the availability of proposed method.
Femtosecond soliton propagation in fibers with slowly decreasing dispersion

We obtain the adiabatic compression of femtosecond solitons in fibers with slowly decreasing dispersion (FSDD’s) and discover the effect of soliton pulse-width stabilization in FSDD’s. A theoretical model for the description of femtosecond-pulse propagation in FSDD’s is presented. The model takes into account higher-order nonlinear and dispersive effects in fibers. We present numerical simulations of a generalized nonlinear Schrodinger equation and the adiabatic soliton approximation theory as well. Good quantitative agreement between the theory and the experiments is seen. The effect of soliton pulse-width stabilization in FSDD’s is described as a result of the combined action of the third-order dispersion and Raman self-scattering effects. We also show the possibility of obtaining high-quality pulses with less than a 15-fs pulse width in the 1.6-μm spectral region by soliton compression in FSDD’s.
Eddy current testing of anomalies in conductive materials. I. Qualitative imaging via diffraction tomography techniques

The authors consider the analysis of eddy current testing of defects in conductive materials. The authors investigate the application of reflection-mode diffraction tomography (DT) imaging techniques. First, exact synthetic data are calculated for various canonical configurations using a method of moments, and they are compared with those calculated by a finite-element code and with experimental data. Analysis of these data in particular evidences interest and some limitations of the Born approximation. Second, two imaging algorithms are proposed and investigated from numerical simulations; the first directly originates from ultrasonic DT where most of the attenuation is neglected, and the other approximately accounts for the skin effect. >
Structural Analysis of Discrete Data with Econometric Applications

The thirteen papers in "Structural Analysis of Discrete Data" are previously unpublished major research contributions solicited by the editors. They have been specifically prepared to fulfill the two-fold purpose of the volume, first to provide the econometrics student with an overview of the present extent of the subject and to delineate the boundaries of current research, both in terms of methodology and applications. "Coordinated publication of important findings" should, as the editors state, "lower the cost of entry into the field and speed dissemination of recent research into the graduate econometrics classroom. "A second purpose of the volume is to communicate results largely reported in the econometrics literature to a wider community of researchers to whom they are directly relevant, including applied econometricians, statisticians in the area of discrete multivariate analysis, specialists in biometrics, psychometrics, and sociometrics, and analysts in various applied fields such as finance, marketing, and transportation.The papers are grouped into four sections: "Statistical Analysis of Discrete Probability Models, " with papers by the editors and by Steven Cosslett; "Dynamic Discrete Probability Models, " consisting of two contributions by James Heckman; "Structural Discrete Probability Models Derived from Theories of Choice, " with papers by Daniel McFadden, Gregory Fischer and Daniel Nagin, Steven Lerman and Charles Manski, and Moshe Ben-Akiva and Thawat Watanatada; and "Simultaneous Systems Models with Discrete Endogenous Variables, " with contributions by Lung-Fei Lee, Jerry Hausman and David Wise, Dale Poirier, Peter Schmidt, and Robert Avery.Among the applications treated are income maintenance experiments, physician behavior, consumer credit, and intra-urban location and transportation.
A Trust Region Algorithm with Memory for Equality Constrained Optimization

In this paper, we present a trust region algorithm with memory for equality constrained optimization problems. Different from the traditional trust region algorithms, our trust region model includes memory of the past iterations, which makes the algorithm more farsighted in the sense that its behavior is not completely dominated by the local nature of the objective function, but rather by a more global view. The global convergence is established by using a nonmonotone technique. We report numerical tests to examine the effectiveness of the algorithm.
Structural and ferroelectric properties of the c‐axis oriented SrBi2Ta2O9 thin films deposited by the radio‐frequency magnetron sputtering

Radio‐frequency magnetron sputtering was used to deposit SrBi2Ta2O9 ferroelectric thin films on Pt(111)/Ti/SiO2/Si(001) substrates. Thin films were deposited at room temperature with argon pressures of 0.5–100 mTorr and with sputtering power of 2.5 W/cm2. The crystal orientations of thin films were strongly affected by the argon pressures, the c‐axis oriented SrBi2Ta2O9 thin film was obtained with argon pressure of 30 mTorr. The crystal structures of the c‐axis oriented SrBi2Ta2O9 thin film were investigated by x‐ray diffraction methods: θ‐2θ scan, rocking curve, and φ scans. The well aligned microstructure was observed with the average grain size of about 2000 A in an atomic force microscopic image. Ferroelectric properties were observed for the c‐axis oriented thin film: Pr*−PrΛ and Ec were 9.7 μC/cm2 and 50 kV/cm, respectively, with excitation voltage of 3 V.
Estimating utilities from individual health preference data: a nonparametric Bayesian method

Summary. A fundamental benefit that is conferred by medical treatments is to increase the health‐related quality of life (HRQOL) that is experienced by patients. Various descriptive systems exist to define a patient's health state, and we address the problem of assigning an HRQOL value to any given state in such a descriptive system. Data derive from experiments in which individuals are asked to assign their personal values to various health states. We construct a Bayesian model that takes account of various important aspects of such data. Specifically, we allow for the repeated measures feature that each individual values several different states, and the fact that individuals vary markedly in their valuations, with some people consistently providing higher valuations than others. We model the relationship between HRQOL and health state nonparametrically. We illustrate our method by using data from an experiment in which 611 individuals each valued up to six states in the descriptive system known as the SF‐6D system. Although the SF‐6D system distinguishes 18000 different health states, only 249 of these were valued in this experiment. We provide posterior inference about the HRQOL values for all 18000 states.
ACCURATE AND EFFICIENT COMPUTATION OF MOM MATRIX INVOLVING 2D TRIANGULAR BASIS FUNCTION WITH LINE MATCHING

To speed up the matrix-fill time of Method of Moments (MoM) matrix, an approximate analytical expression for the integration of the Green's function involving two-dimensional triangular basis function with line matching has been derived. A full approximate expression is first obtained through direct integration of the Taylor's series expansion of the Green's function. Based on the distance between the source and observation points, a criterion is established to reduce the full expression to a much-simplified expression. The simplified expression improves the computational efficiency further to fill up the MoM matrix without compromising the solution accuracy.
Infrared study of the Crab pulsar: the «shoulder» pulse and the 3.45 micron pulse profile

Infrared measurements of the Crab pulsar with the NASA IRTF 3.0 m telescope show that the spectrum of the main pulse turns downward for wavelengths longer than 3 . mu.m. The ''shoulder'' pulse discovered by Pennypacker is measured in the 0.9--2.4 . mu.m region, but disappears at 3.5 . mu.m. This pulse rises from 0 to 20% of the height of the main pulse within 1 to 2 ms after the main pulse peak and decays with a 4 to 5 ms time constant. Excess infrared flux also appears after the interpulse. The main peak itself may be narrower at 3.45 . mu.m than in the optical to 2.2 . mu.m band.
Numerical methods for light propagation in large LC cells: a new approach

Accurate numerical methods for the propagation of light in large 3D samples with strong lateral variation of the director field require prohibitive amounts of time. We consider and compare a standard spectral method and the Finite Difference in Frequency Domain method, showing that the CPU time can be reduced by one or two orders of magnitude using a perturbation approach or a recently developed Reduced Order Method. The equations obtained are applied to liquid crystal cells with in-plane switching, illuminated by a large incoherent source. The developed formalism, based on numerically exact equations, is particularly suitable for treating magnetic or optically active media and for extending to such media the well known approximations based on the 4 × 4 (Berreman) or 2 × 2 (Jones) matrices.
Computational fluid dynamics methods for hypersonic flow around blunted-cone-cylinder-flare

This paper presents an investigation of numerical schemes for the hypersonic flow around a blunted-cone– cylinder–flare (HB-2). The investigation is based on a finite volume computational fluid dynamics code using the Harten–Lax–van Leer–contact Riemann solver in conjunction with four numerical reconstruction schemes with order of accuracy ranging from second–ninth order. Comparisons are presented with experimental data for the pressure and heat transfer. The results show that very-high-order schemes such as weighted essentially nonoscillatory fifthand ninth-order methods may provide slightly better results for freestreamMach numbers less than 10; however, there are no obvious benefits over second-order methods for Mach numbers greater than 10.
Use of group theory in symmetrical 3-D eddy-current problems

Geometrical symmetry often occurs in computational electromagnetics. However, it is generally not taken into account when the excitations do not share this symmetry. A rationale is required, and group theory gives the only valuable tool for this purpose. It provides a symmetric decomposition of any problem that allows its study on a reduced part of the initial geometry. This way of treating field problems generally leads to substantial computational savings. The symmetry concept is applied in the paper to 3-D linear eddy-current analysis, where the numerical scheme used is a mixed FEM-BEM method. Detailed examples are presented to demonstrate the efficiency of the use of symmetry.
How I became a torchbearer for matrix theory

Some time ago in our public library I picked up a book, The Best of All Possible Worlds, by Peter F. Drucker, a professor of social science at Claremont Graduate School. In that book, Drucker writes about a pupil of Riemann who was to write his thesis on quaternions. Riemann had seen their importance to his own areas of study, and his student saw that they would lead to the subject that we now call matrix algebra, which has become all the rage. But matrices were not always the rage. They have played a large role in group theory since the work of Elie Cartan, and they play a role in physics and in statistics. Still, matrix theory reached me only slowly. Since my main subject was number theory, I did not look for matrix theory. It somehow looked for me. In what follows a number of instances of such events are sketched.
Closed hierarchy of correlations in Markovian open quantum systems

We study the Lindblad master equation in the space of operators and provide simple criteria for closeness of the hierarchy of equations for correlations. We separately consider the time evolution of closed and open systems and show that open systems satisfying the closeness conditions are not necessarily of Gaussian type. In addition, we show that dissipation can induce the closeness of the hierarchy of correlations in interacting quantum systems. As an example we study an interacting optomechanical model, the Fermi–Hubbard model, and the Rabi model, all coupled to a fine-tuned Markovian environment and obtain exact analytic expressions for the time evolution of two-point correlations.
A peaks‐over‐threshold analysis of extreme wind speeds

The analysis which follows provides both point and interval estimates of 10-, 20-, 50-, and 100-year return values for wind speeds at the five locations. Wind speed is the primary quantity of interest, and it was decided to ignore wind direction and surface pressure, the other two potentially useful variables. Furthermore, the frequency of measurement is unnecessary for the problem at hand, and it was felt that little loss in information would result from replacing hourly wind-speed observations by daily maxima. Thus, the starting point for this analysis is the sequence of consecutive daily maxima of the hourly wind-speed observations over the given period of record, for each station.
Efficient solution of nonlinear ordinary differential equations expressed in S-system canonical form

Ordinary differential equations can be recast into a nonlinear canonical form called an S-system. Evidence for the generality of this class comes from extensive empirical examples that have been recast and from the discovery that sets of differential equations and functions, recognized as among the most general, are special cases of S-systems. Identification of this nonlinear canonical form suggests a radically different approach to numerical solution of ordinary differential equations. By capitalizing on the regular structure of S-systems, efficient formulas for a variable-order, variable-step Taylor-series method are developed. The minimum improvement in efficiency over conventional Runge–Kutta methods is shown to be more than 20 to 60 percent for equations expressed in S-system form. Tests with implemented methods demonstrate that 10- to 100-fold reductions in time are actually realized for solution of S-systems. To examine the potential benefit of recasting ordinary differential equations and then sol.
An analysis of efficiency in Senior Secondary Schools in the Gambia 2006 – 2008: Educational inputs and production of credits in English and Mathematics subjects

Abstract This paper employs a stochastic production frontier model to assess the efficiency of the senior secondary schools in the Gambia. It examines their efficiency in using and mixing the educational inputs of average teacher salary, average teacher education, average teacher experience and students to teacher ratio in producing the number of students scoring credit and above in English and Mathematics. The schools are categorized into three types: the Government schools, the subsidized schools and the private schools. The paper finds no evidence that the private schools are different from the subsidized schools, but there is robust evidence that the private schools are significantly different from the Government schools. The average teacher salary is found to be irrelevant to the student performance, whereas high average teacher experience significantly improves student performance, and high student-to-teacher ratio significantly negates the student performance. Private schools appear to be the most efficient in 2006, but from 2007 to 2008, the performance of the schools in general is found to be highly volatile and unpredictable. Only one school emerges to consistently maintain a superior efficient performance throughout the three years studied.
A new and sophisticated electrochemical scanning tunneling microscope design for the investigation of potentiodynamic processes

One of the main topics in electrochemistry is the investigation of the potential controlled solid/liquid interface. As a local probe technique electrochemical scanning tunneling microscopy becomes more and more important for the analysis of atomic structures and local structuring effects. The described microscope is optimized for potentiodynamic imaging, i.e., the sample potential can be varied in a wide range during the scan of an image. In combination with cyclic voltammetry potential induced phase transitions on the surface can be imaged and directly correlated to distinctive profiles in the simultaneously recorded voltammogram. The new design grew out of the parallel development of the tunneling unit and the electrochemical periphery. This guarantees the best adaptation of tunneling microscopy to electrochemistry and vice versa. Low drift, high resolution, flexibility, reliability, and ease of handling are the characteristics of the new instrument.
Synchronization between two coupled direct current glow discharge plasma sources

Experimental results on the nonlinear dynamics of two coupled glow discharge plasma sources are presented. A variety of nonlinear phenomena including frequency synchronization and frequency pulling are observed as the coupling strength is varied. Numerical solutions of a model representation of the experiment consisting of two coupled asymmetric Van der Pol type equations are found to be in good agreement with the observed results.
The Spatial and Temporal Moments of Tracer Concentration in Disordered Porous Media

This study develops a methodology for deriving the spatial and temporal moments of tracer concentration in disordered geological formations and suggests a geostatistical formalism for interpolation and prediction of concentration, conditional to concentration measurements. The required spatial and temporal moments of the concentration are obtained by a biparticle tracking scheme which yields the bivariate probability distribution function of particle displacements in terms of the input log conductivity random field and the prevailing flow conditions. The structure of the moments of the concentration is discussed, and we show that (1) the concentration correlation function is anisotropic, nonstationary and nonsymmetrical; (2) there is a larger correlation between concentrations along the mean flow direction than normal to it; (3) the correlation between the concentration at any two points with fixed coordinates on a moving (Lagrangian) coordinate system increases with travel time; (4) the correlation function necessarily assumes negative values beyond a certain threshold distance; and (5) the concentration variance is finite even when neglecting pore-scale dispersion. Application of the geostatistical prediction algorithm using the concentration spatial/temporal moments shows a good potential for reducing prediction uncertainty.
The Ricci curvature of Diff S1/SL(2, R)

Previous calculations of the Ricci curvature for the manifold Diff Diff(S1)/S1 are extended to Diff(S1)/SL(2R ). These manifolds are distinguished by being coadjoint orbits of Diff(S1) which admit compatible symphectic and complex structures, making them Kahler manifolds.
Parametric down-conversion with coherent pulse pumping and quantum interference between independent fields

The process of parametric down-conversion pumped by a short coherent pulse is analysed. The coherence properties of the down-converted field are investigated. It is found that the spectrum of the down-conversion is mostly determined by the nonlinear medium and is independent of the width of the short pumping pulse and that it is impossible to realize a transform-limited two-photon state. Fourth-order interference between a weak coherent pulse and the down-converted pulse is considered. It is found that high visibility near 100% is achievable by means of narrow optical filtering. It is shown that by gating the detection on one of the down-converted photons, a transform-limited single-photon pulse is achievable in the other conjugate field, but its pulse width is shorter than that of the down-converted pulse and its peak position is uncertain within the pulse width of the down-converted light. However, with narrow optical filtering on the gating detection process, a transform-limited single-photon state can be obtained in the gated field with its peak position synchronized to the pump pulse. The possibility for the realization of a multi-photon interference experiment is explored for the quantum state measurement of the single-photon state.
Multivariate quality control solved by one‐class partial least squares regression: identification of adulterated peanut oils by mid‐infrared spectroscopy

The Partial least squares class model (PLSCM) was recently proposed for multivariate quality control based on a partial least squares (PLS) regression procedure. This paper presents a case study of quality control of peanut oils based on mid‐infrared (MIR) spectroscopy and class models, focusing mainly on the following aspects: (i) to explain the meanings of PLSCM components and make comparisons between PLSCM and soft independent modeling of class analogy (SIMCA); (ii) to correct the estimation of the original PLSCM confidence interval by considering a nonzero intercept term for center estimation; (iii) to investigate the potential of MIR spectroscopy combined with class models for identifying peanut oils with low doping concentrations of other edible oils.
Corner liquid imbibition during capillary penetration in lithographically made microchannels

The authors investigate the formation of liquid layers at corners of lithographically made microchannels during capillary filling. The microflow and shape of the liquid-air interface is studied through an optically transparent microfluidic device. The experimental findings at early stages of layer formation are supported by three-dimensional lattice Boltzmann simulations, allowing to predict the shape and dynamics of the corner films and highlighting their dependence on the fluid contact angle.