Miracle-dz/UniFAR-FTUs huggingface dataset:
Maximum likelihood computations with repeated measures: application of the EM algorithm

Abstract The purpose of this article is to consider the use of the EM algorithm (Dempster, Laird, and Rubin 1977) for both maximum likelihood (ML) and restricted maximum likelihood (REML) estimation in a general repeated measures setting using a multivariate normal data model with linear mean and covariance structure (Anderson 1973). Several models and methods of analysis have been proposed in recent years for repeated measures data; Ware (1985) presented an overview. Because the EM algorithm is a general-purpose, iterative method for computing ML estimates with incomplete data, it has often been used in this particular setting (Dempster et al. 1977; Andrade and Helms 1984; Jennrich and Schluchter 1985). There are two apparently different approaches to using the EM algorithm in this setting. In one application, each experimental unit is observed under a standard protocol specifying measurements at each of n occasions (or under n conditions), and incompleteness implies that the number of measurements actua.
Robustness of the Likelihood Ratio Test for a Change in Simple Linear Regression

Abstract This article examines the robustness of the likelihood ratio tests for a change point in simple linear regression. We first summarize the normal theory of Kim and Siegmund, who have considered the likelihood ratio tests for no change in the regression coefficients versus the alternatives with a change in the intercept alone and with a change in the intercept and slope. We then discuss the robustness of these tests. Using the convergence theory of stochastic processes, we show that the test statistics converge to the same limiting distributions regardless of the underlying distribution. We perform simulations to assess the distributional insensitivity of the test statistics to a Weibull, a lognormal, and a contaminated normal distribution in two different cases: fixed and random independent variables. Numerical examples illustrate that the test has a correct size and retains its power when the distribution is nonnormal. We also study the effects of the independent variable's configuration with the.
A Modern Introduction to Particle Physics

Scattering and particle interaction space-time symmetries internal symmetries unitary groups and SU(3) SU(6) and quark model colour, gauge principle and quantum chromodynamics heavy flavours Heavy Quark Effective Theory (HQET) neutrino weak interactions properties of weak hadronic currents and chiral symmetry electroweak unification deep inelastic scattering particle mixing and CP-violation weak decays of heavy flavours grand unification, supersymmetry and strings cosmology and particle physics quantum field theory renormalization group and running coupling constant.
An Extrapolated Version of the Gordon's Interpolation Applied to the Method of Moments

When applied to the electromagnetic scattering problem, the method of moments (MoM) results in a full matrix representation which requires a large amount of computational resources. To circumvent this problem, the numerical technique presented here works directly on the efficiency of the interpolation scheme used in the MoM, introducing an extrapolated version of Gordon's interpolation. This new method is applied to a generalized version of the volume surface integral equation to solve two-dimensional scattering problems. It is shown how it results in the decomposition of the problem into three simpler independent problems which can be performed either in sequence or in parallel. The performances of the method are confirmed by convergence tests, and the extrapolated MoM is illustrated on the case of the scattering by a microstrip structure.
Plausibility of multivariate normality assumption when multiply imputing non-Gaussian continuous outcomes: a simulation assessment

Multiple imputation under the assumption of multivariate normality has emerged as a frequently used model-based approach in dealing with incomplete continuous data in recent years. Despite its simplicity and popularity, however, its plausibility has not been thoroughly evaluated via simulation. In this work, the performance of multiple imputation under a multivariate Gaussian model with unstructured covariances was examined on a broad range of simulated incomplete data sets that exhibit varying distributional characteristics such as skewness and multimodality that are not accommodated by a Gaussian model. Behavior of efficiency and accuracy measures was explored to determine the extent to which the procedure works properly. The conclusion drawn is that although the real data rarely conform with multivariate normality, imputation under the assumption of normality is a fairly reasonable tool, even when the assumption of normality is clearly violated; the fraction of missing information is high, especially when the sample size is relatively large. Although we discourage its uncritical, automatic and, possibly, inappropriate use, we report that its performance is better than we expected, leading us to believe that it is probably an underrated approach.
Domain formation in epitaxial Pb(Zr, Ti)O3 thin films

Ferroelectric twin-domain structures in epitaxial Pb(Zr, Ti)O3 (PZT) thin films grown on various single-crystal substrates such as MgO(001), KTaO3(001), and SrTiO3(001) were investigated by two-dimensional reciprocal space mapping using synchrotron x-ray diffraction. Each system showed a characteristic domain structure. PbTiO3 thin films grown on MgO(001) showed highly c-axis oriented domain structures consisting of a periodic array of 90° twinlike domains. Perfectly c-axis oriented films were obtained on SrTiO3(001), while the films grown on KTaO3(001) showed a-domain dominant structures with a small amount of c domains embedded in matrix a domains. Contributions of net elastic strain stored in each heteroepitaxial layer and its relaxation to the final domain structures were evaluated considering thermodynamic equilibrium relief of coherency strain by misfit dislocation generation at the film growth temperature. A comparison between theoretical consideration and experimental results clearly demonstrates .
Two Dimensional Long Transmission Line-Frequency Domain (Ltl-Fd) Treatment of Dielectric Loaded Waveguides

In this paper, two dimensional long transmission line-frequency domain (LTL-FD) circuits [1] are used to determine cutoff wavenumbers of slab loaded arbitrarily shaped cylindrical waveguides. Treatment of interfaces between different media is given. The resonance frequencies of the resulting circuits are the required cutoff frequencies of the guide. The problem is reduced to an eigenvalue problem, which is solved to get the required solution. Numerical results are given to compare results with available analytical solutions and results given by other reported methods.
A Lagrangian Objective Analysis Technique for Assimilating In Situ Observations with Multiple-Radar-Derived Airflow

Abstract A new Lagrangian analysis technique is developed to assimilate in situ boundary layer measurements using multi-Doppler-derived wind fields, providing output fields of water vapor mixing ratio, potential temperature, and virtual potential temperature from which the lifting condensation level (LCL) and relative humidity (RH) fields are derived. The Lagrangian analysis employs a continuity principle to bidirectionally distribute observed values of conservative variables with the 3D, evolving boundary layer airflow, followed by temporal and spatial interpolation to an analysis grid. Cloud is inferred at any grid point whose height z > zLCL or equivalently where RH ≥ 100%. Lagrangian analysis of the cumulus field is placed in the context of gridded analyses of visible satellite imagery and photogrammetric cloud-base area analyses. Brief illustrative examples of boundary layer morphology derived with the Lagrangian analysis are presented based on data collected during the International H2O Project (IHO.
On absorption by hot interstellar gas. I - Forbidden Fe X 6375

The spectra of 32 stars have been observed in the region of the coronal forbidden Fe X 6375 line at detection limits near an equivalent width of 1 mA in the best cases. No absorption which can be attributed to Fe X ions in hot interstellar gas is seen in any of these spectra except one, in general agreement with predictions based on a three-phase model of the interstellar medium. Toward Cephei an absorption line is measured with an equivalent width of 8.1 + or - 2 mA, a width corresponding to 20 + or - 5 km/s or a temperature not greater than about (0.5 + or - 0.25) x 10 to the 6th K, and, if it is caused by Fe X ions, a radial velocity of -355 km/s. On that hypothesis, the hot interstellar gas constitutes at least 30 percent of the column density of gas along this light path. Six new telluric lines also are detected, and the 6376, 6379 A diffuse interstellar bands are observed toward all six appreciably reddened stars and one high-latitude star.
Strong Consistency of Approximate Maximum Likelihood Estimators with Applications in Nonparametrics

Wald's general analytic conditions that imply strong consistency of the approximate maximum likelihood estimators (AMLEs) have been extended by Le Cam, Kiefer and Wolfowitz, Huber, Bahadur, and Perlman. All these conditions use the log likelihood ratio of the type log[f(x, 0)/f(x, 60)], where Oo is the true value of the parameter. However these methods usually fail in the nonparametric case. Thus, in this paper, for each 0 $ 00, we look at the log likelihood ratio of the type log[f (x, 0)/f (x, r(0) )], where O,(0) is a certain parameter selected in a neighborhood V, of 60. Some general analytic conditions that imply strong consistency of the AMLE are given. The results are shown to be applicable to several nonparametric families having densities, e.g., concave distributions functions, and increasing failure rate distributions. In particular, they can be applied to several censored data cases.
The dissipation rate coefficient of turbulence is not universal and depends on the internal stagnation point structure

The energy dissipation rate coefficient of statistically stationary homogeneous isotropic turbulence depends on the external force sustaining the turbulence irrespective of Reynolds number. This nonuniversality is established by proving that the Taylor length is proportional to the mean distance between stagnation points and thereby relating the energy dissipation rate coefficient to the stagnation point structure of the turbulence which is shown to depend on the structure of the large eddies. Confirmation of these relations is obtained at moderate Reynolds numbers by a series of direct numerical simulations where the large-scale forcing is systematically varied.
Narrow beam RGB array optic

The popularity of multi-primary color LED light engines presents unique challenges to optical design. Multiple design requirements must be satisfied including the achievement of uniform color projection in the field for archetainment, accent, and show lighting, as well as high illuminance at distances greater than 5 meters. A novel collimation optic is presented which includes multiple combinations of color enhancement and collimation features.
Roughness-induced non-wetting

In the original article the author has remarked a minor mistake on page 169, which changes the result displayed in eq. (6), but does not affect any of the conclusions of the paper. In line 13, the exponent n is to be changed to n/2. Consequently, in all following expressions ln b is to be multiplied by 2 wherever it appears. Equation (6) thus reads
Politics, Process, and Pyramids

Of the many noteworthy features of John Coulson's (1978) review of the Emergency School Aid Act (ESAA) evaluation, the most important may be the perspective that is provided on the many methodological problems that arise in such large-scale evaluation efforts. Technical writings on evaluation have been dominated by proposals, counterproposals, and rebuttals of various statistical adjustment techniques, such as analysis of covariance, which purport to make valid assessments of treatment effects from data on nonequivalent groups. Coulson's review may well signal some redirection of technical effort. His presentation of various methodological problems lends support to the view that the marginal gain for evaluation research and practice from future technical research on adjustment techniques may be small compared to the potential gains from work on other conceptual and methodological problems. The comments to follow are an attempt to highlight some promising topics for future work in evaluation methodology and to identify some functions and characteristics of the evaluation enterprise that influence or constrain methodological decisions.
Two-band DMD-based infrared scene simulator

OPTRA is developing a two-band midwave infrared scene simulator based on digital micromirror devices (DMD). The simulator is intended for testing a number of different infrared tracking technologies. Our approach allows for the relative intensities of the two spectral bands to be varied for realistic simulations of an approaching target. The system employs a broadband IR (thermal) source whose energy is spectrally filtered via a series of bandpass filters acting as dichroic beamsplitters prior to being imaged onto two DMDs - one for each spectral band. The "on" reflected images from the two DMDs are then fused, expanded by a telescope, and transmitted towards the unit under test. The relative intensities of each spatial element of the two bands are controlled through the duty cycle of "on" versus "off" of the related micromirror. In this paper we present a breadboard design, build, and test which establishes the feasibility of our approach. A description of the opto-mechanical system is given along with radiometric performance projections. Results from breadboard testing, including maximum radiant intensity and radiant intensity resolution, and a series of simulated images are shown.
The Electron‐Beam Ion Trap

The mention of few‐electron atoms usually brings to mind hydrogen, helium or other light elements in neutral form. However, these simple atoms are part of a sequence of ions having the same number of electrons but different nuclear charges. For example, the hydrogen‐like sequence spans neutral hydrogen through hydrogen‐like uranium, U91+. Both the atomic physics and the applications of the most highly charged ions in such isoelectronic sequences are receiving increasing attention. Recently the electronbeam ion trap has made it possible to produce and study any such ion in a modest‐sized apparatus (figure 1).
Polariton Effect in Distributed Feedback Microcavities

The excitonic and photonic states in distributed feedback (DFB) microcavities may strongly couple to form DFB cavity polaritons, provided that excitonic oscillator strength is large enough. In this paper we theoretically analyse the optical properties of DFB microcavities related to polariton effect. A numerical method based on scattering matrix formalism has been developed to solve the Maxwell's equations for layered system with periodical patterning of layers. To incorporate polaritonic effect in our model we included the exciton poles in dielectric susceptibility of one of the patterned layers. Using this method we reproduce the characteristic features, demonstrated in recent experiments [Fujita et al.: Phys. Rev. B 57 (1998) 12428], such as anticrossing behavior of transmission dips in vicinity of the excitonic resonance and strong polarization dependence of their position and depth. ©2001 The Physical Society of Japan
The lunar regolith: physical characteristics and dynamics

The fine size fraction of the lunar regolith (less than 1 mm mean particle diameter) is composed mostly of particles that owe their origins either directly or indirectly to the impacts of meteoroids on the lunar surface. Comminution of pre-existing rocks and particles is the dominant process affecting the characteristics of the regolith. However, agglutination of pre-existing particles by the glassy, molten spatter and ejecta from small meteoroid impacts is a competing constructive process of low efficiency. Grain size frequency distributions of the less than 1 mm fraction of the regolith tend to be slightly bimodal, with a broad mode in the 1-40 size range (500- 62.5 pm due mostly to agglutination and another mode at approximately 50 (31.3 pm) and finer that appears to be caused by the ballistic influx of fine particles from older (finer) regolith. In general, the size frequency distribution curves are nearly symmetrical and indicate poor to very poor sorting. There is a strong correlation of sample mean grain size (and other size parameters) with the length of time that the regolith has had to accumulate at each landing site. The greater the total length of regolith accumulation time, the greater the comminution by meteoroids, and hence the finer the sample mean grain size and the greater the total agglutinate content. These properties also correlate positively with solar wind implanted carbon and nitrogen contents. Thus, sample mean size, agglutinate content, solar wind nitrogen and carbon, as well as solar particle track densities, can all be used as measures of regolith ‘maturity’. Local sample collection site geology, such as proximity to boulders or recent craters, strongly influences sample modal particle type populations and grain size characteristics. Lunar chondrules of several types have been identified in the regolith and rock samples. Many of these chondrules have textures that are identical with many meteoritic chondrules. The chondrules in lunar surface materials appear to result from lunar impact processes. It may be that chondrules have originated in many meteorites by some of the same processes. If true, this occurrence has important implications for the origin and history of chondritic meteorites.
Noise in InAs/GaSb type-II superlattice photodiodes

The noise behavior of InAs/GaSb superlattice photodiodes for high-performance thermal imaging in the mid- and longwavelength infrared atmospheric windows at 3-5 μm and 8-12 μm is complex and up to now not very well understood. In order to characterize these devices we have developed a noise measurement setup with a noise current resolution in the femtoampère range. First, we show that, when sidewall leakage is absent, InAs/GaSb superlattice photodiodes with a low dark current very close to the generation-recombination limited dark current level of the bulk behave according to the well-known shot noise expression. Next, we investigate a set of 18 large-area diodes with a bandgap in the midwavelength infrared regime, which show an increased dark current depending linearly on the applied reverse bias. For these diodes the common shot noise model generally fails to describe the noise experimentally observed in the white part of the noise spectrum. Instead, we find that McIntyre’s excess noise model for electron-initiated avalanche multiplication processes fits our data remarkably well for the entire set of diodes, which covers about three orders of magnitude in dark current and a wide range of reverse bias voltage. Thus, to explain the mechanism leading to the increased reverse dark current and observed excess noise we tentatively suggest that primary electrons originating from Shockley-Read-Hall states within the space charge region might initiate avalanche multiplication processes within high electric field domains localized around sites of macroscopic crystallographic defects.
Improved articulatory models

After a brief historical review of articulatory models, a factor analysis of the lateral shapes of the vocal tract is described. In the analysis, the profiles are specified by the sum of a small number of linear components. Studies at CNET indicate that, by using an arbitrary factor analysis in connection with the principal component analysis, it is possible to derive a linear model in which each component can be interpreted in articulatory terms, such as jaw position, tongue‐body position, etc. The statistical model, therefore, can be regarded as an articulatory model. The analysis of radiocinematographic data exhibits that the same vowel can be produced differently depending on speakers and phonetic contents, suggesting a compensatory articulation. Such a model is also useful in investigating the articulatory‐acoustic relationships. For example, F1–F2 trajectories are calculated by varying a specific parameter value, while the remaining parameter values are fixed appropriate for a vowel. The results sho.
Classifying Proximity Soundings with Self-Organizing Maps toward Improving Supercell and Tornado Forecasting

AbstractThe self-organizing map (SOM) statistical technique is applied to vertical profiles of thermodynamic and kinematic parameters from a Rapid Update Cycle-2 (RUC-2) proximity sounding dataset with the goal of better distinguishing and predicting supercell and tornadic environments. An SOM is a topologically ordered mapping of input data onto a two-dimensional array of nodes that can be used to classify large datasets into meaningful clusters. The relative ability of SOMs derived from each parameter to separate soundings in a way that is useful in discriminating between storm type, location, and time of year is discussed. Sensitivity to SOM configuration is also explored. Simple skill scores are computed for each SOM to evaluate the relative potential of each variable for future development as a method of probabilistic forecasting. It is found that variance in SOM nodes is reduced compared to the overall dataset, indicating that this is a viable classification method. SOMs of profiles of wind-derived .
Kolmogorov–Zurbenko filters

We reviewed the properties of the Kolmogorov–Zurbenko (KZ) filter and its extensions with applications in high resolution signal and image processing. The KZ filter is defined as an iteration of a moving average (MA) filter. The impulse response function of the KZ filter is a convolution of the rectangular window being used in a MA filter. Zero derivatives at the edges of the impulse response function make it a sharply declining function, providing high frequency resolution. The KZ Fourier transform (KZFT) is derived from the KZ filter by applying it to Fourier transform. Extensions of the KZ filter and the KZFT are demonstrated with examples. Copyright © 2010 John Wiley & Sons, Inc.
Diode lasers in photomedicine

Recent developments of high-power infrared and visible semiconductor (diode) lasers make this class of miniaturized laser sources very attractive for medical applications. Principles of operation of diode lasers are reviewed, and potential areas of applications are discussed. Possible uses of high-power incoherent diodes in photomedieine are presented.