Miracle-dz/UniFAR-FTUs huggingface dataset:
Intelligent interactive multiobjective optimization method and its application to reliability optimization

In most practical situations involving reliability optimization, there are several mutually conflicting goals such as maximizing the system reliability and minimizing the cost, weight and volume. This paper develops an effective multiobjective optimization method, the Intelligent Interactive Multiobjective Optimization Method (IIMOM). In IIMOM, the general concept of the model parameter vector is proposed. From a practical point of view, a designer's preference structure model is built using Artificial Neural Networks (ANNs) with the model parameter vector as the input and the preference information articulated by the designer over representative samples from the Pareto frontier as the desired output. Then with the ANN model of the designer's preference structure as the objective, an optimization problem is solved to search for improved solutions and guide the interactive optimization process intelligently. IIMOM is applied to the reliability optimization problem of a multi-stage mixed system with five different value functions simulating the designer in the solution evaluation process. The results illustrate that IIMOM is effective in capturing different kinds of preference structures of the designer, and it provides a complete and effective solution for medium- and small-scale multiobjective optimization problems.
Probability distribution functions for solar and stellar magnetic fields

Abstract Magneto-convection structures the magnetic field in solar and stellar atmospheres over scales that for the Sun span about 8 orders of magnitudes, down to the magnetic diffusion scale of order 10 m. The statistical properties of this structuring are governed by probability density functions (PDFs), for the vertical and transverse field components as well as for the field inclination. Due to the fractal nature of the field pattern these PDFs appear to have a high degree of scale invariance. There are serious pitfalls in the derivations of empirical PDFs, pitfalls that are particularly severe in the case of the field inclination. This explains the fragmentary and rather unreliable PDF information available in the published literature. Here we discuss the nature of these pitfalls and indicate how they may be avoided, using Hinode quiet-sun Stokes vector data to derive PDFs for the field strength and field inclination.
The 19 April 1996 Illinois Tornado Outbreak. Part II: Cell Mergers and Associated Tornado Incidence

Abstract In the 19 April 1996 Illinois tornado outbreak, cell mergers played a very important role in the convective evolution. With a large number of cells forming within a short time period, the early stages of cell organization were marked by cell merger interactions and cell attrition that led to a pattern of isolated tornadic supercells as described in Part I of this study. Twenty-six mergers were documented and analyzed. Storm-rotation-induced differential cell propagation accounted for 58% of these 26 cell mergers while differing cell speeds prompted 27% of the mergers. Cell merger characterizations were utilized to describe the cell reflectivity coalescence morphology including aspects of new cell development, development along the periphery of an existing cell, or an upward pulse in the cell intensity of a dominant cell. In cases where the merging cells were of similar intensity, a rapidly developing cellular pulse “bridging” the two echoes was often observed. When the relationship between short-.
Extraction of net interfacial polarization charge from Al0.54In0.12Ga0.34N/GaN high electron mobility transistors grown by metalorganic chemical vapor deposition

AlxInyGa(1-x-y)N materials show promise for use in GaN-based heterojunction devices. The growth of these materials has developed to the point where they are beginning to see implementation in high electron mobility transistors (HEMTs) and light emitting diodes. However, the electrical properties of these materials are still poorly understood, especially as related to the net polarization charge at the AlInGaN/GaN interface (Qπ(net)). All theoretical calculations of Qπ(net) share the same weakness: dependence upon polarization bowing parameters, which describe the deviation in Qπ(net) from Vegard's law. In this study, direct analysis of Qπ(net) for Al0.54In0. 12Ga0.34N/GaN HEMTs is reported as extracted from C-V, I-V, and Hall measurements performed on samples grown by metalorganic chemical vapor deposition. An average value for Qπ(net) is calculated to be 2.015 × 10−6 C/cm2, with just 6.5% variation between measurement techniques.
Optimal control of double output induction generator using optimal regulator theory

In this paper, a control scheme is designed to obtain satisfactory optimum power from the double output induction generator (DOIG). The proposed controller is used to optimize a nonlinear objective function with different effective equality constraints. Minimum power losses and consequently maximum generated power can be obtained by controlling the inverter firing angle. The constraints are selected according to the optimal restrictions in order to ensure the duplication of the generated power when the speed varies from synchronous to double of the synchronous speed. The desired cost function in the nonlinear form is realized corresponding to the selected equality constraints when all the system optimal and stable requirements are taken into consideration. The optimal regulator theory is used and the Hassian matrix technique is selected in this study to facilitate the calculation of the optimal operation conditions.
Deep Orographic Storms over the Sierra Nevada. Part II: The Precipitation Processes

Abstract The thermodynamic and kinematic structure of two stable orographic storms were described in Part I based on instrumented aircraft data and single Doppler radar data. The precipitation processes in these storms are described in this paper. The storms were deep with cloud top temperatures of about −25°C. Below the melting level the cloud droplet population was continental with a mean droplet diameter <10 μm. Above the melting level the cloud droplet population was maritime with mean droplet diameters of 20 to 30 μm. Near the −5°C level a peak in ice crystal concentration of 30 to 200 L−1 was observed. Since most of the ice crystals were needles, are rime-splintering secondary ice crystal production processes as generally described by Hallett and Mossop was probably occurring. Calculations of the condensation supply rates were compared with the depletion rates by deposition and accretion. The depletion rates by deposition were less than half the condensation supply rates, and the liquid water conten.
MULTIPLE SPIRAL BRANCHES ON LATE ASYMPTOTIC GIANT BRANCH STARS

We present one-dimensional hydrodynamical models that suggest a new mechanism for generating spiral structures around evolved stars. In these models, the pulsation of the star initiates the mass outflow and generates shock waves from a static atmosphere. An orbiting companion perturbs the outflow, creating a long-period series of shocks with different speeds and gas density that form spiral arms around the star. The spacing and number of spirals generated are predictable from pulsation and orbital periods. Companions in close orbits create up to four spiral arms, while companions farther out predominantly form single spiral arms. The interaction also produces a variety of density and temperature structures close to the star in the equatorial plane. This study extends the set of mechanisms for explaining the morphologies of protoplanetary nebulae.
Weak gravitational lensing of distant galaxies

We analyze the two-point statistics of the gravitationally induced ellipticities of distant images whick provide a direct probe of the mass fluctuation spectrum P(k). The analysis extends previous work in the following respects : (1) We explore the relation between the ellipticity pattern of the background galaxies and the projected density of foreground matter. (2) We calculate angular power spectra, using the analogue of Limber's equation in the Fourier domain, as well as angular correlation functions. (3) The analysis is valid for arbitrary evolution of P(k) and for an arbitrary distance distribution for the galaxies
Constructing an influence function of robust learning algorithm based on error distributions for the neural networks

Various robust learning algorithms have been proposed in the literature to overcome the effects of outliers. In those learning algorithms, the robust learning algorithms are divided into two categories. One is directly adopts the theory of the M-estimator. The other is the least mean log square learning algorithm in which errors are assumed to be the Cauchy distribution. However, outliers not only affect the fatness, but also may slightly affect the skewness of the distribution. In the paper, the errors distribution is assumed to belong to the generalized exponential family and an adaptive robust learning algorithm is then proposed. The idea of our approach is to adaptively construct the influence function based on the current observed error distribution. Since the kurtosis can be used to measure the fatness of a distribution, it is employed for identifying a coefficient in the generalized exponential distribution family through the moment recursive relations. The proposed algorithm has been employed under various noise distributions and the results have demonstrated superiority over other robust learning algorithms.
First-principles investigations of orbital magnetic moments and electronic structures of the double perovskites Sr 2 FeMoO 6 , Sr 2 FeReO 6 , and Sr 2 CrWO 6

The electronic structures and magnetic properties of double perovskites ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6},$ ${\mathrm{Sr}}_{2}{\mathrm{FeReO}}_{6},$ and ${\mathrm{Sr}}_{2}{\mathrm{CrWO}}_{6}$ have been studied by using the full-potential linear muffin-tin orbital method within the local-spin-density approximation (LSDA) and the generalized gradient approximation (GGA). The on-site Coulomb energy U has also been taken into account in both schemes $(\mathrm{LSDA}+U$ and $\mathrm{GGA}+U). $ The results predict a half-metallic ferrimagnetic band structure with total spin magnetic moment of $4{\ensuremath{\mu}}_{B},$ $3{\ensuremath{\mu}}_{B},$ and $2{\ensuremath{\mu}}_{B}$ per formula unit for ${\mathrm{Sr}}_{2}{\mathrm{FeMoO}}_{6},$ ${\mathrm{Sr}}_{2}{\mathrm{FeReO}}_{6},$ and ${\mathrm{Sr}}_{2}{\mathrm{CrWO}}_{6},$ respectively. By including the spin-orbit coupling in the self-consistent calculations, we find that the $5d$ transition-metal atoms W and Re exhibit large unquenched orbital magnetic moments because of significant spin-orbit interaction in $5d$ orbitals. On the other hand, in Fe and Cr $3d$ and Mo $4d$ orbitals, the orbital moments are all quenched even though the on-site Coulomb energy U is taken into account. This is in strong contrast to the enhanced large $3d$ orbital moments in CoO and NiO but similar to the quenched orbital moment in ${\mathrm{CrO}}_{2}. $
On Minimax Fractional Programming of Generalized Convex Set Functions

Abstract We derive necessary and sufficient optimality conditions for the discrete minimax programming problem with subdifferentiable ( I , ρ, θ)-convex set functions. Then we apply these optimality criteria to construct two models of parameter-free dual problems and a third model of another dual problem. We also establish weak, strong, and strictly converse duality theorems.
An investigation on magnetic responses in Ag-SiO2-Ag nanosandwich structures

In this work, we investigate magnetic responses in various Ag-SiO2-Ag nanosandwich structures at visible wavelengths. The two electric resonant modes corresponding to the in-phase (symmetric) and anti-phase (asymmetric) electric dipole on the top and the bottom nanopillars are observed by the finite difference time domain (FDTD) simulation. In the asymmetric resonant mode, the phases of electric fields oscillating in the top and bottom pillars have opposite directions, leading to a virtual current loop that induces the magnetic field reversal. The nanosandwich structure produces a large enhancement of the magnetic field as the thickness of SiO2 nanopillar is much smaller than wavelength. By increasing the diameter of nanopillars from 150 nm to 250 nm, the inverse magnetic response wavelength shifts from 532 nm to 690 nm. On account of the magnetic field reversal caused by the anti-phase electric dipole coupling, the real part of the equivalent permeability of the film is negative. Therefore, the wavelength range associated with the intensity of inverse magnetic response is tunable by varying the size of Ag-SiO2-Ag nanosandwich structure. The equivalent electromagnetic parameters of the Ag-SiO2-Ag nanosandwich thin film prepared by glancing angle deposition are derived from the transmission and the reflection coefficients measured by walk-off interferometers. The measured results indicate that film exhibit double negative properties and lead to negative values of the real parts of equivalent refractive indices -0.854, -1.179, and -1.492 for λ = 532 nm, 639 nm, and 690 nm, respectively. Furthermore, the real part of permeability is negatively enhanced to be -4.771 and the maximum value of figures of merit (FOM) recorded being 6.543 for p-polarized light at λ = 690 nm. Finally, we analyze the admittance loci for our nanosandwich thin film. This analysis can be applied to interpret extraordinary optical properties such as negative index of refraction from Ag-SiO2-Ag nanosandwich films.
Simple three-dimensional vortex motions in coflowing jets and wakes

The vortex patterns which occur in coflowing jets and wakes at moderate Reynolds numbers (of order 500) are examined in detail. Flow visualization is used in conjunction with a flying hot-wire system which allows instantaneous velocity vector fields to be rapidly measured and related to the smoke patterns. The structures were made perfectly periodic in time by artificial stimulation. The experiments were therefore completely deterministic. This newly developed data-acquisition technique does not require the use of Taylor's hypothesis for inferring patterns from a fixed streamwise position. It therefore allows the vector fields of rapidly evolving patterns to be produced. It also allows the phenomenon of three-dimensional vortex pairing to be studied. The classification of patterns and conjectured topologies made by Perry & Lim (1978a, b) and the interpretations of Perry, Lim & Chong (1980) and Perry & Watmuff (1981) are examined. In the light of more-detailed measurements, it is found that some of these interpretations require modification. Vortex ‘skeleton’ models of the patterns are constructed and it is found that the Biot-Savart law gives vector fields which are in reasonable agreement with the experiments. It is also found that the power-spectral density of a periodic array of eddies can be explained in terms of potential flow vortices.
Coexistence in a Two-Dimensional Lotka-Volterra Model

We study the stochastic spatial model for competing species introduced by Neuhauser and Pacala in two spatial dimensions. In particular we confirm a conjecture of theirs by showing that there is coexistence of types when the competition parameters between types are equal and less than, and close to, the within types parameter. In fact coexistence is established on a thorn-shaped region in parameter space including the above piece of the diagonal. The result is delicate since coex- istence fails for the two-dimensional voter model which corresponds to the tip of the thorn. The proof uses a convergence theorem showing that a rescaled process converges to super-Brownian motion even when the parameters converge to those of the voter model at a very slow rate.
Applications of fuzzy inference systems in global approximate desgin optimization

The paper describes the construction of global function approximation models for use in design optimization via global search techniques such as genetic algorithms. Two different approximation methods referred to as evolutionary fuzzy modeling (EFM) and neuro-fuzzy modeling (NFM) are implemented in the context of global approximate optimization. EFM and NFM are based on soft computing paradigms utilizing fuzzy systems, neural networks and evolutionary computing techniques. Such approximation methods may have their promising characteristics in a case where the training data is not sufficiently provided or uncertain information may be included in design process. Fuzzy inference system is a central of identifying the input/output relationship in both methods. The paper introduces the general procedures including fuzzy rule generation, membership function selection and inference process for EFM and NFM, and presents their generalization capabilities in terms of number of fuzzy rules and training data with application to a three-bar truss optimization.
A collisionless plasma thruster plume expansion model

A two-fluid model of the unmagnetized, collisionless far region expansion of the plasma plume for gridded ion thrusters and Hall effect thrusters is presented. The model is integrated into two semi-analytical solutions valid in the hypersonic case. These solutions are discussed and compared against the results from the (exact) method of characteristics; the relative errors in density and velocity increase slowly axially and radially and are of the order of 10−2–10−3 in the cases studied. The plasma density, ion flux and ambipolar electric field are investigated. A sensitivity analysis of the problem parameters and initial conditions is carried out in order to characterize the far plume divergence angle in the range of interest for space electric propulsion. A qualitative discussion of the physics of the secondary plasma plume is also provided.
Structural Models in Anthropology

Foreword J. A. Barnes Acknowledgements 1. Graph theory and anthropology 2. Graphs 3. Signed graphs 4. Digraphs 5. Graphs and matrices 6. Structural duality 7. Networks 8. Graphs and groups Appendix: axiomatics References Index.
SIMPLE PLASTICITY SAND MODEL ACCOUNTING FOR FABRIC CHANGE EFFECTS

A simple stress-ratio controlled, critical state compatible, sand plasticity model is presented, first in the triaxial and then in generalized stress space. The model builds upon previous work of the writers, albeit the presentation here is made with extreme simplicity in mind, and three novel aspects are introduced. The first is a fabric-dilatancy related quantity, scalar valued in the triaxial and tensor valued in generalized stress space, which is instrumental in modeling macroscopically the effect of fabric changes during the dilatant phase of deformation on the subsequent contractant response upon load increment reversals, and the ensuing realistic simulation of the sand behavior under undrained cyclic loading. The second aspect is the dependence of the plastic strain rate direction on a modified Lode angle in the multiaxial generalization, a feature necessary to produce realistic stress-strain simulations in nontriaxial conditions. The third aspect is a very systematic connection between the simple triaxial and the general multiaxial formulation, in order to use correctly the model parameters of the former in the implementation of the latter. The simulative ability of the model is illustrated by comparison with data over a very wide range of pressures and densities.
A search for millisecond periodic and quasi-periodic pulsations in low-mass X-ray binaries

The results of a Fourier analysis to detect fast periodic and quasi-periodic pulsations in the X-ray emission from the sources 4U 0614 + 091, 4U 1636 - 536, 4U 1735 - 44, 4U 1820 30, GX 5 - 1, GX 9 + 9, Ser X-1, and Cyg X-2 are presented. This search has been carried out for the first time in the soft energy band (0.2-2.0 keV), using data from the Einstein Observatory high resolution imager instrument. An approximate method of minimizing the decrease in search sensitivity produced by the Doppler shift of the pulse periods due to source orbital motion is discussed. No pulsations have been detected, and upper limits, which depend on the orbital parameters assumed for the sources, are set on the pulsed flux fraction.
Nonlinear wavelet denoising for improved bearing estimation in ocean under non-Gaussian noise conditions

Summary form only given. Bearing estimation of underwater acoustic sources is an important aspect of passive localization of targets in the ocean. The performance of standard bearing estimation techniques degrades under low signal-to-noise ratio (SNR) conditions of the signal received at the sensor array. In ocean environments, the noise process is usually assumed to be a Gaussian process. However, statistical measurements of ocean acoustic ambient noise data indicate that noise statistics may deviate significantly from Gaussian to strongly non-Gaussian in some environments. In the last few years, there has been a considerable interest in the use of the discrete wavelet transform (DWT) for denoising signals. It is known that the conventional wavelet transform, which is linear, can be used for denoising signals in Gaussian noise, but this method is not suitable if the noise is strongly non-Gaussian. In this paper, we exploit the possibility of employing the nonlinear wavelet denoising to improve the performance of bearing estimation techniques in the ocean in strongly non-Gaussian noise environments. We propose the application of nonlinear wavelet denoising to the noisy signal at each sensor in the sensor array to boost the SNR before performing bearing estimation by known techniques (MUSIC and subspace intersection). It is shown that denoising leads to significant improvement in the performance of the bearing estimator. Computational results are presented to show that denoising leads to significant reduction in the mean square errors (MSE) of the bearing estimates, and enhancement of resolution of closely spaced sources.
Frequency selective surfaces for high sensitivity terahertz sensing

An apporach for the sensing of small amounts of chemical and biochemical material is presented. A frequency selective surface made from asymmetric split ring resonators is excited with free space radiation. Due to interference effects a resonance occurs with a steep flank in the frequency response which is shifted upon dielectric loading. Utilizing a strong E-field concentration by selective loading the detection of very small amounts of probe material becomes possible. The functionality is proven by numerical simulation and the optimization of structure and loading is performed.
Optimal linear growth in magnetohydrodynamic duct flow

Transient linear growth in laminar magnetohydrodynamic duct flow is analysed. The duct is straight with rectangular cross-section and electrically insulating walls. The applied uniform magnetic field is oriented perpendicular to the mean flow direction and parallel to one of the walls. Optimal perturbations and their maximum amplifications over finite time intervals are computed. The optimal perturbations are increasingly damped by the magnetic field, localized in the boundary layers parallel to the magnetic field irrespective of the duct aspect ratio. Typically, the optimal perturbations have non-vanishing streamwise wavenumber as found in magnetohydrodynamic channel flow with spanwise magnetic field. The Hartmann boundary layers perpendicular to the magnetic field do not contribute to the transient growth.