bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of cerebral cortex viscoelastic property estimation with nonlinear inversion magnetic resonance elastography
Authors: Hiscox Lucy V , McGarry Matthew D J , Johnson Curtis L 
Published: March 2022

Abstract

Objective. Magnetic resonance elastography (MRE) of the brain has shown promise as a sensitive neuroimaging biomarker for neurodegenerative disorders; however, the accuracy of performing MRE of the cerebral cortex warrants investigation due to the unique challenges of studying thinner and more complex geometries. Approach. A series of realistic, whole-brain simulation experiments are performed to examine the accuracy of MRE to measure the viscoelasticity (shear stiffness, μ, and damping ratio, ξ) of cortical structures predominantly effected in aging and neurodegeneration. Variations to MRE spatial resolution and the regularization of a nonlinear inversion (NLI) approach are examined. Main results. Higher-resolution MRE displacement data (1.25 mm isotropic resolution) and NLI with a low soft prior regularization weighting provided minimal measurement error compared to other studied protocols. With the optimized protocol, an average error in μ and ξ was 3% and 11%, respectively, when compared with the known ground truth. Mid-line structures, as opposed to those on the cortical surface, generally display greater error. Varying model boundary conditions and reducing the thickness of the cortex by up to 0.67 mm (which is a realistic portrayal of neurodegenerative pathology) results in no loss in reconstruction accuracy. Significance. These experiments establish quantitative guidelines for the accuracy expected of in vivo MRE of the cortex, with the proposed method providing valid MRE measures for future investigations into cortical viscoelasticity and relationships with health, cognition, and behavior.
Cone-beam breast CT using an offset detector: effect of detector offset and image reconstruction algorithm
Authors: Tseng Hsin Wu , Karellas Andrew , Vedantham Srinivasan 
Published: March 2022

Abstract

Objective. A dedicated cone-beam breast computed tomography (BCT) using a high-resolution, low-noise detector operating in offset-detector geometry has been developed. This study investigates the effects of varying detector offsets and image reconstruction algorithms to determine the appropriate combination of detector offset and reconstruction algorithm. Approach. Projection datasets (300 projections in 360°) of 30 breasts containing calcified lesions that were acquired using a prototype cone-beam BCT system comprising a 40 × 30 cm flat-panel detector with 1024 × 768 detector pixels were reconstructed using Feldkamp–Davis–Kress (FDK) algorithm and served as the reference. The projection datasets were retrospectively truncated to emulate cone-beam datasets with sinograms of 768

×

768 and 640

×

768 detector pixels, corresponding to 5 cm and 7.5 cm lateral offsets, respectively. These datasets were reconstructed using the FDK algorithm with appropriate weights and an ASD-POCS-based Fast, total variation-Regularized, Iterative, Statistical reconstruction Technique (FRIST), resulting in a total of 4 offset-detector reconstructions (2 detector offsets × 2 reconstruction methods). Signal difference-to-noise ratio (SDNR), variance, and full-width at half-maximum (FWHM) of calcifications in two orthogonal directions were determined from all reconstructions. All quantitative measurements were performed on images in units of linear attenuation coefficient (1/cm). Results. The FWHM of calcifications did not differ (P > 0.262) among reconstruction algorithms and detector formats, implying comparable spatial resolution. For a chosen detector offset, the FRIST algorithm outperformed FDK in terms of variance and SDNR (P < 0.0001). For a given reconstruction method, the 5 cm offset provided better results. Significance. This study indicates the feasibility of using the compressed sensing-based, FRIST algorithm to reconstruct sinograms from offset-detectors. Among the reconstruction methods and detector offsets studied, FRIST reconstructions corresponding to a 30 cm × 30 cm with 5 cm lateral offset, achieved the best performance. A clinical prototype using such an offset geometry has been developed and installed for clinical trials.
A comprehensive physics based surface potential and drain current model for SiGe channel dual programmable FETs
Authors: Pandey Priyanka , Kaur Harsupreet 
Published: March 2022

Abstract
In the present work, a comprehensive analytical model for surface potential and drain current has been developed for double gate silicon-germanium channel dual programmable FETs (SiGe-DP-FET) which is capable to conduct both in n- as well as p-modes. The developed model accurately predicts the impact of mole fraction (m) variation in Si(1 − m)Ge
m
channel on various device characteristics such as energy band, surface potential, electric field, drain current, and transconductance. While deriving the surface potential expression, the active SiGe channel is bifurcated in three regions such that regions I and III denote the two gated regions while region II denotes the ungated region. Further, in order to compute the expression for surface potential, 2D Poisson’s equation has been solved in gated regions while linear approximation has been applied in ungated region and subsequently, the drain current expression has been obtained by integrating the band-to-band generation rate of charge carriers across the source side Schottky junctions. Moreover, in order to validate the proposed model, the analytical results are compared and verified with 2D TCAD ATLAS simulated results and it has been observed that the results obtained using proposed model match well with the simulated results.
Hot carrier spatio-temporal inhomogeneities in ultrafast nanophotonics
Authors: Schirato Andrea , Crotti Giulia , Proietti Zaccaria Remo , Alabastri Alessandro , Della Valle Giuseppe 
Published: March 2022

Abstract
Light-induced hot carriers in nanostructures and their corresponding optical nonlinearity have been extensively examined during the last decades. However, nonlinear optical effects dictated by the spatio-temporal evolution of out-of-equilibrium electrons at the nanoscale represent a much more recent research focus. Here we theoretically discuss the role of spatial inhomogeneities that energetic electrons feature across individual nanoantennas in metasurface configuration upon illumination with femtosecond laser pulses. As exemplary cases, we consider two-dimensional geometries of gold meta-atoms having either a high aspect ratio or a tapered cross-section and model their ultrafast optical response. A comparison with numerical results obtained either neglecting or accounting for spatial effects indicates that deep sub-wavelength spatio-temporal transients of carriers may have a significant impact on the dynamics of the all-optically modulated signal, with major quantitative corrections up to predicted changes in sign. Our results present hot-electron local inhomogeneities as an emerging subject with potentially relevant applications in various ultrafast nanophotonic configurations.
Electrical conduction mechanism and dielectric relaxation of bulk disodium phthalocyanine
Authors: Alosabi A Q , Al-Muntaser A A , El-Nahass M M , Oraby A H 
Published: March 2022

Abstract
AC conductivity and dielectric characteristics of disodium phthalocyanine (Na2Pc) in a pellet form were investigated in a frequency range from 45 Hz to 3.12 MHz and a temperature range from 303 to 423 K. The charge carrier transport mechanism was determined according to the correlated barrier hopping model (CBH). Also, the electrical parameters were estimated in light of this model. The thermal activation energy of AC conductivity decreases with increasing frequency. The behavior dependence of dielectric loss and dielectric constant on temperature and frequency was discussed. The behavior of dielectric loss was explained based on the Giuntini model. The maximum value of barrier height,

W

M

,

was obtained to equal

0.38

eV
.

The results showed that the type of relaxation mechanism is a non-Debye one. The activation energy is calculated for dielectric relaxation to be

0.36

eV
.
A New Multichannel Parallel Real-time FFT Algorithm for a Solar Radio Observation System Based on FPGA
Authors: Zhang Yuan Y. , Zhang Lei , Shang Zi Q. , Su Yan R. , Wu Zhao , Yan Fa B. 
Published: March 2022

Abstract
The real-time fast Fourier transform (FFT) is the essential algorithm for signal processing in a solar radio receiver. However, field-programmable gate array (FPGA) computation resources have become the limitation of real-time processing of signals with increasing time and spectral resolutions. It is necessary to design a real-time parallel FFT algorithm with reduced resource occupation in the development of future receiving systems. In this paper, we developed a multichannel parallel FFT algorithm named the multichannel parallel real-time fast Fourier transform (MPR-FFT), which can greatly reduce FPGA resource occupation while increasing the real-time processing speed. In this algorithm, the 4L simultaneous N-point FFTs are first converted into L simultaneous 4N-point FFTs. Fusion processing is then performed to obtain the 4 ∗ L ∗ N-point spectrum. This method has been used in developing a solar radio spectrometer, which works in the frequency range of 0.5–15 GHz in the Chashan Observatory. In this spectrometer, 16 channel MPR-FFT with 8k-point data is realized in a Xilinx UltraScale KU115 FPGA. The MPR-FFT algorithm reduced the computational resources to a large extent compared to the Cooley-Tukey-based parallel FFT method; for instance, the Look-Up-Table, Look-Up-Table RAM, Flip-Flop, and Digital Signal Process slices were reduced by 37%, 50%, 17%, and 2.48%, respectively. Although the MPR-FFT consumes 14 block RAM resources more than the Cooley-Tukey-based parallel FFT, the MPR-FFT algorithm presents an overall reduction in resource usage.
The use of interpolation methods for modelling multifactor processes based on an experiment planning matrix
Authors: Konopatskiy E V , Seleznev I V , Bezditnyi A A 
Published: March 2022

Abstract
This article is dedicated to the development of experimental data processing tools based on the geometric theory of multidimensional interpolation. At the same time, a scientific problem was solved, which is dedicated to the analytical determination of models of multifactor processes while maintaining the existing approach to experiment planning This makes it possible not only to use interpolation methods for the mathematical description of new experiments, but also to use the experimental data obtained earlier to improve their mathematical interpretation. The paper provides two examples that confirm the effectiveness of the proposed approach to constructing models of multivariate processes using multivariate interpolation methods. The first of the above examples contains two geometric models of the stress-strain state of metal polyhedral bent struts, which are presented in the form of ruled response hypersurfaces passing through 8 predetermined points in the 4-dimensional space. The second one is dedicated to the construction of a 2-factor process process using a 2- parameter parabolic geometric interpolant with subsequent optimization by methods of mathematical analysis of a function of two variables. As a result, the optimization of the aerated concrete manufacturing process was carried out to achieve the maximum values of the ultimate strength in compression after heat and moisture treatment.
Analysis of modern measuring instruments for research diagnostic systems of print media equipment
Authors: Shmelev F Yu , Orlova E Yu , Sultanova Yu M , Varepo L G 
Published: March 2022

Abstract
The quality of printing products substantially depends on the accuracy of the individual mechanisms of the printing equipment. Since technological processes usually last in a period of a second, conventional measuring instruments turn out to be too inertial; therefore, to detect deviations of the given parameters (loads, locations, accelerations) from the calculated values, various sensors are used. The work is devoted to the selection of diagnostic tools for typical measurements used in print media equipment on printing equipment. Possibilities of parallel measurements and mutual analysis of signals of the designed diagnostic systems for research of parameters of the equipment of the print media industry are considered.
Discrete-event simulation of load distribution between server stations
Authors: Denisov O V 
Published: March 2022

Abstract
The simulation model of the computational load balancing in a server complex using a balancing server is proposed. The server load balancing model was developed using MATLAB/Simulink/SimEvents/Stateflow tools. The SimEvents based model makes it possible to simulate the server complex as a queuing system and to take into account the sporadic occurrence of requests. The Stateflow based event-driven model simulates the system with a variable time delay in data transmission channels and simulates state transitions for servers. This discrete-event simulation model allows evaluating the possibility of rational use of computational resources and reducing the time of service. In addition, the model allows to investigate the effectiveness of load balancing systems at the stage of their development.
Factorial research and the recognition problem solution using the example of obstructive sleep apnea syndrome
Authors: Goltyapin V V 
Published: March 2022

Abstract
The article is devoted to the problem of identifying factors directly or indirectly influencing the presence of obstructive sleep apnea syndrome in patients (OSAS) and solving the problem of pattern recognition in the factor space using the example OSAS. A factorial study was carried out for each group of indicators characterizing the condition of patients with OSAS, optimal factor structures were formed and the interpretation of the identified latent-integrative factors was carried out. It was implemented Bayes’ formula for calculating probabilities by OSAS groups in factor space. It is proposed formula for the transition from initial data to factors for finding the n-dimensional distribution density which is necessary for solving problems of recognition and based on the Bayesian criterion. There are given the proof of the transition formula and computational algorithms for the recognition problem.
Cylindrical shear waves in soil around underground pipelines
Authors: Khusanov B E , Rikhsieva B B 
Published: March 2022

Abstract
A method of numerical solution of one-dimensional problem of cylindrical shear wave propagation in an elastic and elastic-plastic soil is developed in the article using the finite difference method. The numerical results obtained are presented in the form of graphs. From the results obtained, the attenuation of the parameters (shear stress, shear strain, and angular velocity) of cylindrical wave propagation with distance in an elastic and elastic-plastic soil was determined. The attenuation of waves with distance is justified by the dissipation of strain energy on the expanding cylindrical soil layer. In the case of load exceeding the elastic limit, plastic strains occur in soil near the point of load application. The boundaries of elastic-plastic strain of soil are determined.
Electrodynamic long-stroke drive as an inertial compensator of low-frequency vibroactive forces
Authors: Burian Yu A , Sitnikov D V , Burian A A 
Published: March 2022

Abstract
The article discusses various possibilities of using an electrodynamic drive with an increased displacement of a movable permanent magnet as a low-frequency inertial compensator of vibroactive forces.The main attention is paid to the analysis of an active dynamic vibration damper (ADVD) when installing an electrodynamic compensator (EDC) on the base near vibration supports and when connecting the EDC moving mass with a vibroactive mass using a spring. It is shown that the considered ADVD is effective as a vibration isolator in the low-frequency range.
Development of antenna system for use in meteorological and climatic control complexes
Authors: Kudryashov M A , Belousov O A , Tetyukhin V I , Kiryupin M M , Belyaev V P , Nagornova I V , Bezzateeva E G 
Published: March 2022

Abstract
The synthesis of a cylindrical antenna array for ground-based mobile weather monitoring complexes, based on quadrifilar radiators, is considered. The basic mathematical expressions for determining the electrodynamic characteristics of both the radiator from the antenna array and the AA itself are presented. Various phenomenological models of these radiators are considered. The approach to the synthesis of phenomenological models of the radiator and antenna array as a whole is described. The results of such synthesis are given, and the main characteristics and values of DG, CG, SWR, RP for the given type of radiator and AA in the corresponding frequency range are obtained. Techniques for using phenomenological models for operational synthesis of electrodynamic structures such as cylindrical AA and quadrifilar radiator are developed and described in detail. The possibility of applying this approach to the synthesis of this type of structures for radar weather monitoring systems is shown.
Effectiveness analysing of modification of training data set for voice forgery detection system
Authors: Mikhaltsov V E , Semenova Z V , Stepanova E A 
Published: March 2022

Abstract
Paper presents data of the experiments with the advanced model of voice authentication. The main idea of the research is to prove or deny the hypotese that adding generated fake data to the training set of the background model help to increase the probability of detecting fake data of the target announcer. Processing the results of a series of experiments did not confirm the hypothesis.
Investigation of the operation of a microwave autogenerator with emitters of various designs
Authors: Vavilov I S , Yachmenev P S , Fedyanin V V , Zharikov K I , Stepen’ P V , Lukyanchik A I 
Published: March 2022

Abstract
This paper presents the results of experimental studies of 15 design versions of capacitive and induction type microwave antennas. As part of the work on the development of an accelerator ion thruster, 32 radiator designs were studied. The research was carried out in order to select the optimal design of a plasma-generating microwave antenna for installation in the discharge chamber of a prototype ion thruster. The volt-ampere characteristics (VAC) were obtained the microwave generator when working with each design of the radiator in a vacuum chamber. The VAC is obtained in the presence and absence of a high-frequency discharge.
Review of Nmij Studies Using The Primary pH Method
Authors: Maksimov I , Asakai T , Ohata M 
Published: March 2022

Abstract
In the field of pH measurements, the NMIJ, as designated metrology body, provides the traceability to international pH standards for a country, disseminate the certified buffer solutions for JCSS [1] and develops new measurements technologies. In this review we would like to present the last topic with the short description of some recent studies involving the Harned cell
Selection of a regression model for graduation of measuring instruments when it is necessary to estimate stability of the calibration curve
Authors: Zubkov P N , Nechaev N V 
Published: March 2022

Abstract
A method for choosing the best regression model for the cases when the measuring task is associated with the study of the stability of the metrological characteristics of the calibrated measuring instrument is described. A description of the experiment set up when using this method in the course of researching the metrological characteristics of measuring instruments for the numeric concentration of light air ions is given, and the research results obtained using this method are given.
Development of metrological support for color calibration of digital microscopy systems
Authors: Makhov D S , Samorodova O A , Muravskaya N P , Samorodov A V 
Published: March 2022

Abstract
The article is dedicated to the color reproducibility in images obtained on various digital microscopy systems (DMS). This problem can be solved by color calibration with a special slide. According to the previously formulated requirements, a slide prototype for DMS color calibration was developed and manufactured. Several color calibration algorithms were tested to choose the best one for minimizing the color difference. Color calibration algorithms were based on polynomials of different degrees with and without cross terms for CIE Lab color fields’ coordinates. This comparison was made with the color slide prototype and two DMSs based on Meiji MT4300 and Olympus BX41 microscopes. The comparison proved the polynomials with cross terms of 3rd and 4th degrees to be the best for DMSs based on Meiji and Olympus microscopes, respectively. The minimal color difference with respect to the true color fields’ coordinates was 0.75 ΔE* and 0.66 ΔE* for Meiji and Olympus, respectively. The results indicate the suitability of the slide prototype for DMS color calibration since it is possible to achieve a color difference below the visually distinguishable threshold of 2.2 ΔE*.
Spectral and dosimetric properties of multilayer structures of radiochromic absorbed dose reference materials
Authors: Tenishev V 
Published: March 2022

Abstract
The paper considers a method for extending ionizing radiation absorbed dose measurement range by multilayer technology of one-, two-, three- and four-layer radiochromic films. It shows that this technology expands the AD measurement range to the small dose region of 10-1000 Gy.
Key development stages of reference material for lactose monohydrate composition
Authors: Kasilyunas Anastasia V , Medvedevskikh Maria Yu , Krashenina Maria P , Sergeeva Anna S 
Published: March 2022

Abstract
The article mirrors key stages of development of reference material (RM) for the composition of lactose monohydrate with certified values of mass fraction of water and basic material. The RM could be used in the analytical chemistry and food industry, as well as at identification and assessment of nutritive products safety, int. al., infant food. The RM under development will be intended for metrological assurance of mass fraction of water and basic substance measuring instruments based on usage of thermogravimetric, titrimetric and chromatographic methods, certification of measurement procedures and control of measurement results of lactose monohydrate mass fraction accuracy, used as the host material, and in compositions of organic substances and materials or in measurements of water mass fraction in solid substances and materials, as well as for other kinds of metrological control. Determination of certified value of lactose monohydrate mass fraction in the RM was performed by reference method of iodometric titration and affirmed by mass balance method (one hundred minus the number of impurities) and by calculating-experimental method. The certified value of mass fraction of water was assigned by the Fischer’s method of volumetric titration and confirmed by the thermogravimetric method. Considerable attention was focused to the study of the separation process of sorbed and crystallisation water in a high-purity lactose monohydrate reagent. The results of measurements of the quantitative content of the types of water were considered when assessing the purity of the target substance by various methods. Unlike existing RM of similar composition, the traceability of the certified values of the RM being developed will be ensured to units of values reproduced respectively by the state primary (GET 173-2017) and secondary (GVET 176-1-2010) standards.