Miracle-dz/UniFAR-FTUs huggingface dataset:
Long short-term memory neural network with scoring loss function for aero-engine remaining useful life estimation

Estimation of the aero-engine remaining useful life (RUL) is a significant part of prognostics and health management (PHM) and the basis of condition-based maintenance (CBM) which can improve the reliability and economy. Multiple operating conditions, nonlinear degradation, and early prediction are significant and distinctive issues compared with other prognostics problems. While these issues do not get enough attention and researches in aero-engine RUL estimation. In view of these points, three specific data preparation approaches and a novel loss function are introduced. The data preparation approaches can extract high-quality data for the long short-term memory (LSTM) neural network according to the characteristic of aero-engine degradation data. Among these approaches, operating condition normalization is an effective method to handle the multiple operating conditions problems, and RUL limitation identification is a novel method to identify the turning point of the nonlinear degradation process. The scoring function is an innovative loss function used to replace the mean square error (MSE) loss function which has a preference for early prediction. The comparisons with the original LSTM and some other approaches indicate that the combination of the data preparations and the scoring loss function is an effective solution for the above issues, and can achieve the best performance among the approaches.
Comparing Treatments Using Quality-Adjusted Survival: The Q-TWiST Method

Abstract The quality of life of patients is an important component of evaluation of therapies. We present an overview of a statistical method called Q-TWiST (Quality-Adjusted Time Without Symptoms and Toxicity) which incorporates quality-of-life considerations into treatment comparisons. Multivariate censored survival data are used to partition the overall survival time into periods of time spent in a set of progressive clinical health states which may differ in quality of life. Mean health state durations, restricted to the follow-up limits of the clinical trial, are derived from the data and combined with value weights to estimate quality-adjusted survival. The methodology emphasizes treatment comparisons based on threshold utility analyses that highlight trade-offs between different health state durations; it is not intended to provide a unique result combining quality and quantity of life. We also describe three recent extensions of the methodology: covariates can be included using proportional hazard.
Optimizing strategy for MR imaging gradient coils

An optimization technique for magnetic resonance imaging gradient coils is presented. Assuming the coil in the form of four windings, each having a spiral polygon shape, the coordinates of nodes are varied to optimize the coil performance. The hybrid simulated annealing - Powell technique is used as the numerical tool. Results of calculations for differently formulated goal functions are demonstrated. >
The shear modulus of the neutron star crust and nonradial oscillations of neutron stars

Shear moduli are calculated for bcc crystalline and rapidly quenched Coulomb solids produced by the Monte Carlo simulation method. The shear moduli are calculated up to the transition temperature and include the effects of thermal fluctuations. An effective shear modulus appropriate to an approximate 'isotropic' body is introduced. It is found that the values of the 'average shear modulus' for the quenched solids remain about the same as those for the corresponding bcc crystals, although the individual shear moduli of the former, disordered solids deviate considerably from the cubic symmetry of the latter. These results are applied to analyses of neutron star oscillations. It is found that the periods of the two interfacial modes are increased by about 10 percent compared to previous results, and that s-mode periods are increased by about 30 percent. The periods of the f and p modes are hardly affected at all. The surface g-mode periods are not greatly affected, while the t-mode periods are increased by 20-25 percent. 12 refs.
A GENERAL METHOD FOR STUDYING DIFFERENCES IN FACTOR MEANS AND FACTOR STRUCTURE BETWEEN GROUPS

A statistical model is developed for the study of similarities and differences in factor structure between several groups. The model assumes that the observed variables satisfy a factor analysis model in each group. A method of data analysis is presented which, in contrast to earlier work, makes use of information in the observed means as well as the observed variances and covariances to estimate the parameters in each group, i.e. factor means, factor loadings, factor variances and covariances and unique variances. Usually the units of measurement in the observed variables have no intrinsic meaning and therefore it is only meaningful to compare the relative magnitudes of the parameters for the different groups. The method estimates the parameters for all groups simultaneously and can take into account a priori information about factorial invariance of various degrees.
FERMI-LAT OBSERVATIONS OF THE DIFFUSE γ-RAY EMISSION: IMPLICATIONS FOR COSMIC RAYS AND THE INTERSTELLAR MEDIUM

The γ-ray sky >100 MeV is dominated by the diffuse emissions from interactions of cosmic rays with the interstellar gas and radiation fields of the Milky Way. Observations of these diffuse emissions provide a tool to study cosmic-ray origin and propagation, and the interstellar medium. We present measurements from the first 21 months of the Fermi Large Area Telescope (Fermi-LAT) mission and compare with models of the diffuse γ-ray emission generated using the GALPROP code. The models are fitted to cosmic-ray data and incorporate astrophysical input for the distribution of cosmic-ray sources, interstellar gas, and radiation fields. To assess uncertainties associated with the astrophysical input, a grid of models is created by varying within observational limits the distribution of cosmic-ray sources, the size of the cosmic-ray confinement volume (halo), and the distribution of interstellar gas. An all-sky maximum-likelihood fit is used to determine the XCO factor, the ratio between integrated CO-line intensity and H2 column density, the fluxes and spectra of the γ-ray point sources from the first Fermi-LAT catalog, and the intensity and spectrum of the isotropic background including residual cosmic rays that were misclassified as γ-rays, all of which have some dependency on the assumed diffuse emission model. The models are compared on the basis of their maximum-likelihood ratios as well as spectra, longitude, and latitude profiles. We also provide residual maps for the data following subtraction of the diffuse emission models. The models are consistent with the data at high and intermediate latitudes but underpredict the data in the inner Galaxy for energies above a few GeV. Possible explanations for this discrepancy are discussed, including the contribution by undetected point-source populations and spectral variations of cosmic rays throughout the Galaxy. In the outer Galaxy, we find that the data prefer models with a flatter distribution of cosmic-ray sources, a larger cosmic-ray halo, or greater gas density than is usually assumed. Our results in the outer Galaxy are consistent with other Fermi-LAT studies of this region that used different analysis methods than employed in this paper.
E-products pricing problem under uncertainty: a geometric programming approach

Nowadays e-commerce plays an important role in many business activities, operations and transaction processing. The recent advances on e-businesses have created tremendous opportunities to increase profitability. In this paper, we present an optimal pricing and marketing planning where the primary objective function is to maximise the total profit. The proposed mathematical model is considered with different input parameters and coefficients in uncertain state, and we provide a suitable method that calculates a lower and upper bounds for the objective function of model. The application of proposed problem and solution method is demonstrated by a numerical example.
Non-linear system identification using the Hammerstein model

An algorithm for the identification of non-linear systems which can be described by a Hammerstein model consisting of a single-valued non-linearity followed by a linear system is presented. Cross-correlation techniques are employed to decouple the identification of the linear dynamics from the characterization of the non-linear element. These results are extended to include the identification of the component subsystems of a feedforward process consisting of a Hammerstein model in parallel with another linear system.
Quantum codes over rings

This paper considers the construction of quantum error correcting codes from linear codes over finite commutative Frobenius rings. We extend the Calderbank–Shor–Steane (CSS) construction to these rings. Further, quantum codes are extended to matrix product codes. Quantum codes over 𝔽pk are also obtained from linear codes over rings using the generalized Gray map.
A new approach to the optimization of robust antenna array processors

The authors present a method for solving a class of optimization problems with nonsmooth constraints. In particular, they apply the method to the design of narrowband minimum-power antenna array processors which are robust in the presence of errors such as array element placement, look direction misalignment, and frequency offset. They first show that the constrained minimum power problem has a unique global minimum provided that the constraint set is nonempty. Then it is shown how the design problem derived directly from considerations of the sensitivity of the antenna array processor to errors can be transformed into a quadratic programming problem with linear inequality constraints which can be solved efficiently by the standard active set strategy. They also present numerical results for two types of nonsmooth constraints developed to provided robustness. These results confirm the effectiveness of the method. >
Social Consequences of Homeownership: Evidence from the Home Ownership Scheme in Hong Kong

Abstract:Homeownership is expected to provide a wide range of social benefits. However, the empirical evidence for causation is weak, and knowledge beyond Western countries is even more limited. This article investigates how homeownership affects life satisfaction and subjective class identification in Hong Kong. The Home Ownership Scheme, a large-scale subsidized homeownership program based on a random draw, represents a quasi-experimental setting to identify the causal impact of homeownership. Based on the analyses of data from four waves of the Hong Kong Panel Study of Social Dynamics (HKPSSD) and instrumental variable estimation, we show that homeownership significantly improves life satisfaction among Hong Kong adults, and that those who own a home deem themselves as belonging to a higher social class. This study contributes to the understanding of homeownership effects by providing causal evidence from a Chinese society and sheds light on the effectiveness of housing policies that aim to promote homeownership in Hong Kong and beyond.
A Bayesian Group Sequential Approach for Multiple Endpoints

ABSTRACT Making decisions regarding overall treatment effectiveness can be problematic when one considers multiple outcomes, especially if the treatment effects are discordant across the profile of outcomes. A typical example involves a case where a treatment has both increased efficacy in one endpoint (e.g., improved disease-free survival) and increased side effects (e.g., more acute toxicities). Often a study is designed to test one primary hypothesis while other outcomes vital to the decision-making process are not formally incorporated into the study design. We describe a Bayesian approach that provides a mechanism for combining information from two normally distributed endpoints and accounts for the magnitude of those effects. This procedure is implemented for the case of comparing two different treatments to each other and allows for multiple looks at the data. Information from more than one endpoint is combined through the use of utility functions. Our group sequential procedure is demonstrated for the design of a cancer clinical trial that involves two looks at the data. The example shows the effect of different utility functions applied to the same data. Because the selection of the utility function is crucial to the interpretation of the two endpoints, the results are not invariant to the utility function, and great care must be exercised in choosing an appropriate function. Additionally, since results are not robust to the choice of prior, we select a noninformative prior for our example. Despite some limitations in the specification of the utility structure and prior distribution, our procedure provides a mechanism that is useful for simultaneously monitoring multiple endpoints in a clinical trial.
Type-I mid-infrared InAs/InGaAs quantum well lasers on InP-based metamorphic InAlAs buffers

InAs/InGaAs quantum well laser structures have been grown on InP-based metamorphic In0.8Al0. 2As buffers by gas source molecular beam epitaxy. The effects of barrier and waveguide layers on the material qualities and device performances were characterized. X-ray diffraction and photoluminescence measurements prove the benefits of the strain compensation in the active quantum well region on the material quality. The device characteristics of the lasers with different waveguide layers reveal that the separate confinement heterostructure plays a crucial role on the device performances of these metamorphic lasers. Type-I emissions in the 2–3 µm range have been achieved in these InP-based metamorphic antimony-free structures. By combining the strain-compensated quantum wells and separate confinement heterostructures, the laser performances have been improved and laser emission up to 2.7 µm has been achieved.
Adaptive time-step control in creep analysis

Concerning the integration in time of constitutive relations for Norton-type creep problems two families of algorithms are examined, namely the generalized trapezoidal rule and the generalized midpoint rule. Based on a mathematical concept, the accuracy properties are derived for both stresses and strains. Since the choice of the step-size is crucial for the accuracy of the numerical results, an adaptive step-size procedure is carried out by means of error estimators. Specifically, attention is paid to features arising in the context of a finite element displacement method. Finally, two numerical examples are given to illustrate the effect of the step-size control on the accuracy.
Evidence that genetic drift not adaptation drives fast-Z and large-Z effects in Ficedula flycatchers

The sex chromosomes have been hypothesized to play a key role in driving adaptation and speciation across many taxa. The reason for this is thought to be the hemizygosity of the heteromorphic part of sex chromosomes in the heterogametic sex, which exposes recessive mutations to natural and sexual selection. The exposure of recessive beneficial mutations increases their rate of fixation on the sex chromosomes, which results in a faster rate of evolution. In addition, genetic incompatibilities between sex-linked loci are exposed faster in the genomic background of hybrids of divergent species, which makes sex chromosomes contribute disproportionately to reproductive isolation. However, in birds, which show a Z/W sex determination system, the disproportionate role of the Z-chromosome in adaptation and reproductive isolation is still debated. Instead, genetic drift has been proposed as the main driver of the so-called fast-Z and large-Z effects in birds. Here, we address this question in Ficedula flycatchers based on population resequencing data of six flycatcher species. Our results provide evidence for both the fast-Z and large-Z effects in Ficedula flycatchers and that these two phenomena are driven by genetic drift rather than positive selection. Genomic scans of selective sweeps and fixed differences in fact suggest a reduced action of positive selection on the Z-chromosome. We propose that the observed reduction in the efficacy of purifying selection on the Z-chromosome helps to establish genetic incompatibilities between Z-linked and autosomal loci, which could result in pronounced selective sweep signatures for compensatory mutations on the autosomes.
Discrete‐time neural control for electrically driven nonholonomic mobile robots

An inverse optimal neural controller for discrete‐time unknown nonlinear systems, in the presence of external disturbances and parameter uncertainties, is presented. It is based on a discrete‐time recurrent high‐order neural network trained with an extended Kalman filter‐based algorithm. The applicability of the proposed approach is first tested via simulations for an electrically driven nonholonomic mobile robot, and finally, the proposed methodology is implemented on real time. Copyright © 2012 John Wiley & Sons, Ltd.
Some multivariable orthogonal polynomials of the Askey tableau—Continuous families

A multivariable generalization is presented for all the continuous families of the Askey tableaux. This significantly extends some previously known multivariable Jacobi polynomials. The latter are recovered as a limit case from a family of multivariable continuous Hahn polynomials which in turn are obtained as a limit of some multivariable Wilson polynomials. A continuous analog of the single variable Charlier polynomials is also introduced.
Transcranial alternating current stimulation affects several alpha components depending on their frequencies relative to the stimulation frequency

Background The aftereffects of transcranial alternating current stimulation (tACS), especially targeting occipital alpha oscillations, have been reported to show large individual differences in behavioural effects and neural responsiveness. We predicted that this variance at least partly originates from the fact that multiple alpha components are affected differently by alpha-tACS. Objective To test the above prediction, we decomposed several alpha components from the data and evaluated the aftereffects separately for each component and participant. More specifically, we tested how the difference between the stimulation frequency and peak frequency influences the aftereffects of tACS on each alpha component. Methods Eighteen participants received 20-min tACS or sham stimulation on separate days. Ten minutes of magnetoencephalography data were collected before and after stimulation, and spectral analysis was performed with a high-frequency resolution (0.1 Hz) to disentangle different alpha components based on the difference in peak frequencies and spatial patterns. Results: The results revealed three alpha components with slightly different frequencies. tACS increased or decreased the power of these alpha components depending on the relative frequency difference from electrical stimulation. Furthermore, observable components differed among participants, possibly because of anatomical differences in each alpha source. Conclusion When each alpha component is not analysed separately, the change in overall alpha power will be a combination of decreased or increased components, and inter-individual differences will become larger. Our study highlights the importance of noting the presence of multiple alpha components with relatively small differences in the peak frequency for experimental design and analysis.
Brown–von Neumann–Nash dynamics: The continuous strategy case

In John Nash’s proofs for the existence of (Nash) equilibria based on Brouwer’s theorem, an iteration mapping is used. A continuous- time analogue of the same mapping has been studied even earlier by Brown and von Neumann. This differential equation has recently been suggested as a plausible boundedly rational learning process in games. In the current paper we study this Brown-von Neumann-Nash dynamics for the case of continuous strategy spaces. We show that for continuous payoff functions, the set of rest points of the dynamics coincides with the set of Nash equilibria of the underlying game. We also study the asymptotic stability properties of rest points. While strict Nash equilibria may be unstable, we identify sufficient conditions for local and global asymptotic stability which use concepts developed in evolutionary game theory.
Separation of nonmagnetic metals from solid waste by permanent magnets. I. Theory

A new method of separating nonmagnetic metlas from solid waste is described. The process makes use of the much higher electrical conductivity of metals as compared to that of glass, ceramics, and wood. The separation is achieved by means of a ramp, which has permanent magnets embedded in its surface. The magnets are arranged in stripes of alternating polarity at 45° to the ramp axis. Nonconducting particles will slide straight down the ramp, whereas conducting particles will be deflected laterally. The amount of deflection has been calculated as a function of the length and inclination of the ramp, the period and strength of the magnets at the ramp surface, the conductivity, density, shape, size, and initial velocity of the particles and the coefficient of sliding friction between particles and ramp. The deflection is proportional to the ratio of electrical conductivity to mass density and varies substantially as the 3/2 power of the ramp length. If the particle diameter is small compared to the magnet pe.
Elastic wave band gaps and defect states in two-dimensional composites

Using the plane-wave expansion method, we study the propagation of elastic waves through two-dimensional (2-D) periodic composites which exhibit full band gaps for all the polarizations and directions of the displacements. Defect states created inside those band gaps are also studied by disturbing the periodicity of the lattice. Systems exhibiting such kinds of states can be used as acoustical filters.
Multispectral line confocal imaging microscope for fluorescence applications

We present a novel line confocal microscope for investigating biological samples that simultaneously acquires images from three fluorescent channels. This instrument provides the majority of the benefits of confocal microscopes, such as depth sectioning and improved contrast, while allowing more of the excitation illumination to reach the sample area, resulting in reduced exposure times. One configuration of the line confocal fluorescent microscope is designed to work with a four laser illuminator, and three discrete cameras, while an alternate configuration allows the instrument to act as a multispectral microscope that captures the fluorescent emission over the visible and NIR wavelength range.