With increasing global demand for learning English as a second language, there has been considerable interest in methods of automatic assessment of spoken language proficiency for use in interactive ...electronic learning tools as well as for grading candidates for formal qualifications. This paper presents an automatic system to address the assessment of spontaneous spoken language. Prompts or questions requiring spontaneous speech responses elicit more natural speech which better reflects a learner’s proficiency level than read speech. In addition to the challenges of highly variable non-native, learner, speech and noisy real-world recording conditions, this requires any automatic system to handle disfluent, non-grammatical, spontaneous speech with the underlying text unknown. To handle these, a strong deep learning based speech recognition system is applied in combination with a Gaussian Process (GP) grader. A range of features derived from the audio using the recognition hypothesis are investigated for their efficacy in the automatic grader. The proposed system is shown to predict grades at a similar level to the original examiner graders on real candidate entries. Interpolation with the examiner grades further boosts performance. The ability to reject poorly estimated grades is also important and measures are proposed to evaluate the performance of rejection schemes. The GP variance is used to decide which automatic grades should be rejected. Back-off to an expert grader for the least confident grades gives gains.
Solutions of equations of mathematical physics for the 3D Laplace equation for a hollow cylinder are used to develop an analytical model of an inverted disk magnetoelectric motor with two axial air ...gaps based on the Fourier variable separation method. Unknown constants of this method are found using four known boundary conditions of the electromagnetic field on the common end surfaces of hollow cylinders: scalar magnetic potentials and three coordinate components of magnetic induction do not undergo a jump (discontinuity). If, for convenience of calculation, the magnetic sheets of the windings are located at these boundaries, the magnetic potentials on them will undergo a jump equal to the total current of the magnetic sheet. The distribution curves of magnetic inductions in the air gaps and the values of the electromagnetic torque of the motor are obtained, which are compared with the results of numerical calculation using the Ansys Maxwell program. The good agreement between the results obtained indicate the reliability of the proposed analytical model of a disk-type inverted motor.
Special features of structural and phase transformations during the formation of bainitic steel structure were studied. The possibilities of identifying plate (PM) and lath (LM) martensite after ...quenching, and of tempered martensite (TM) along with upper (UB) and lower (LB) bainite after tempering of quenched steel are described. The morphology and specifics of the formation of UB, LB, and TM in the steel structure were studied. The x-ray phase analysis method was used to show the possibility of identifying phases (PM, LM, residual austenite (
A
res
), TM, UP and LB) and calculating their mass fractions in steel by decomposing the reflections into components. Quenching at 950°C was shown to produce PM and LM in steel with different morphologies and dislocation densities, contents of twins and carbon concentrations in the matrix. Tempering of the quenched steel at 500°C was shown to cause the following phase transition: PM + LM +
A
res
→ UB + LB + TM + PM+ LM+ cementite. The resistance of bainitic steel to sulfide corrosion cracking underloading and to hydrogen embrittlement was assessed.
This publication presents the results of clinical application of the system of non-extensible compression adjustable bandage in the treatment of upper and lower limb lymphedema in 14 patients over a ...period of 2 to 34 months. An adjustable non-extensible compression bandage was used as monotherapy for stage I–IIa congenital limb lymphedema in 5 out-of-hospital patients. Progression of edema was not registered in any case during the follow-up period of up to 34 months. In 7 patients with stage IIB-III limb lymphedema, as well as in a 41-year-old patient with a diagnosis Of: Congenital abnormality development of the lymphatic system, Neurofibromatosis type 1, a disease Recklinghausen adjustable non-stretchable compression the product is used in combination with medical compression hosiery 1–2 compression class international standard RAL-Gz 387 from early (first show after 9–11 days after surgery) and continuing in the distant (period of use up to 22 months) postoperative periods. The return of edema (more than 1 cm when measuring the circumference) of the remodeled limb was observed in 3 patients after 4 months of follow-up. At 22 months (the maximum observation period), 2 patients showed an increase in the circumference of the operated limb to 2.5 cm. The system of non-extensible compression adjustable bandage in real clinical practice shows high efficiency in achieving edema reduction in stage I lymphedema of the extremities for at least 24 months. The use of adaptive compression banding system for the prevention of edema regression after surgical interventions for stage III limb lymphedema was reliably effective for 12 months.
The structure and texture of the fatigue fracture of a tubing sub made of a ferritic–pearlitic steel are studied. The microstructure is found to be characterized by a small grain size, a high ...edge-dislocation density, and a developed crystallographic rolling texture with a tension texture superposed on it. The growth of grains with the {112}〈111〉 and {114}〈221〉 orientations and the suppression of the {001}〈110〉, {112}〈110〉, and {110}〈001〉 texture components are shown to accelerate fatigue fracture.
The Cosmic Ray Energetics And Mass (CREAM) instrument is configured with a suite of particle detectors to measure TeV cosmic-ray elemental spectra from protons to iron nuclei over a wide energy ...range. The goal is to extend direct measurements of cosmic-ray composition to the highest energies practical, and thereby have enough overlap with ground based indirect measurements to answer questions on cosmic-ray origin, acceleration and propagation. The balloon-borne CREAM was flown successfully for about 161days in six flights over Antarctica to measure elemental spectra of Z=1–26 nuclei over the energy range 1010 to >1014eV. Transforming the balloon instrument into ISS-CREAM involves identification and replacement of components that would be at risk in the International Space Station (ISS) environment, in addition to assessing safety and mission assurance concerns. The transformation process includes rigorous testing of components to reduce risks and increase survivability on the launch vehicle and operations on the ISS without negatively impacting the heritage of the successful CREAM design. The project status, including results from the ongoing analysis of existing data and, particularly, plans to increase the exposure factor by another order of magnitude utilizing the International Space Station are presented.
Cosmophysical Research with GAMMA-400 Topchiev, N. P.; Galper, A. M.; Arkhangelskaja, I. V. ...
Physics of atomic nuclei,
08/2023, Letnik:
86, Številka:
4
Journal Article
Recenzirano
The GAMMA-400 gamma-ray telescope is the successor of Soviet and Russian gamma-ray telescopes. GAMMA-400 is being developed for cosmophysical research in accordance with the Russian Federal Space ...Program 2016–2025. The GAMMA-400 experiment will be implemented aboard the Russian astrophysical space observatory in a highly elliptic orbit during 7 years to provide new data on gamma-ray emission mainly from the Galactic plane, Galactic Center, the Sun and cosmic-ray electron
positron fluxes. The main mode of observations will be the continuous point-source mode with the duration of up to
100 days. The GAMMA-400 gamma-ray telescope will study high-energy gamma-ray emission up to several TeV and cosmic-ray electrons
positrons up to 20 TeV. GAMMA-400 will have the never-achieved angular resolution, the high-energy and time resolutions, as well as very good separation efficiency of gamma rays from cosmic-ray background and of electrons
positrons from protons. The distinctive features of GAMMA-400 are the excellent angular resolution of
at
GeV that exceeds resolutions of the space-based and ground-based gamma-ray telescopes by a factor of 5–10, as well as high-energy resolution of
at
GeV. GAMMA-400 studies can discover gamma-ray emission from annihilation or decay of dark matter particles, identify many unassociated discrete sources, explore the structure of extended sources, search for gamma-ray bursts and solar gamma-ray flares, improve the data on cosmic-ray electron
positron spectra for energies of >50 GeV.
The results of a study into the electrical and optical characteristics of an overvoltage nanosecond atmospheric pressure discharge between electrodes made of a superionic conductor (SIC) (Ag
2
S) in ...krypton are presented. The destruction of electrodes in the discharge and the introduction of Ag
2
S vapor into the interelectrode gap occurred due to the microexplosions of inhomogeneities on the working surfaces of polycrystalline electrodes (the formation of ectons) in order to synthesize thin films based on this compound on the surface of a dielectric substrate mounted near the electrodes. Numerically solving the Boltzmann kinetic equation for the electron energy distribution function, the temperature and the electron density in the discharge, the specific discharge power losses for the main electronic processes, and the rate constants of the electronic processes depending on the parameter
E
/
N
for the plasma of vapor-gas mixtures based on krypton and silver sulfide have been calculated. Homogeneous thin films based on silver sulfide are synthesized on the quartz substrates by the gas-discharge method under conditions of ultraviolet assisted discharge plasma.
The characteristics of a pulse periodic source of a long-range UV radiation with overvoltage pumping by a bipolar discharge of nanosecond duration between copper electrodes in argon at atmospheric ...pressure are investigated. Copper vapors were introduced into the discharge due to the ectonic mechanism when a sufficient amount of the electrode material vapors is introduced into the discharge gap due to microexplosions of inhomogeneities of the surface of metal electrodes in a strong electric field of an overvoltage high-current nanosecond discharge. The characteristics of an overvoltage nanosecond discharge at a distance between the electrodes of 2 mm are studied. The emission spectra of the discharge were analyzed, and the intensity of the UV radiation of a point emitter was optimized depending on the supply voltage of the high-voltage modulator and the repetition rate of discharge pulses. The identification of the emission spectra of plasma made it possible to establish the main excited plasma products that form the spectrum of the UV radiation of the plasma. The study of the spectral characteristics of plasma based on gas-vapor mixtures “copper–argon” showed that the most intense were the spectral resonance lines of the copper atom and ion. It was found that a space-uniform overvoltage nanosecond discharge was ignited between copper electrodes at an interelectrode distance of 2 mm. It was found that the maximum value of the average UV power at
p
(Ar) = 101 kPa was observed for the UV-A range.
The results of studies of spectral, temporal, and energy characteristics of radiation in a gas discharge plasma based on a mixture of mercury diiodide vapor with helium and nitrogen in the spectral ...range of 350–800 nm are presented. Plasma was produced by a barrier discharge in a device with a cylindrical aperture. The electrodes 0.2 m in length were placed at a distance of 0.015 m. The amplitude of the pump pulses, their duration, and frequency were equal to 20–30 kV, 150 ns, and 1–20 kHz, respectively. Radiation of mercury monoiodide exciplex molecules was revealed in the visible spectra region. Dependences of the plasma optical characteristics on the partial pressures of the mixture components were established.
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