2687-0517 Computing, Telecommunication and Control 15 1 2022 1-72
RAR RUS 7-18 Naval Academy named after Admiral of the Fleet of the Soviet Union N.G. Kuznetsov Tipikin Aleksey alextip@mail.ru
St. Petersburg, Russian Federation
 Method of obtaining global digital maps of underlying surface electric characteristics in the very low frequency band The conductivity and dielectric permittivity of the underlying surface are part of the initial data necessary for calculating the energy parameters of radio tracks. The lack of complete information about the electrical characteristics of the Earth surface indicates the relevance of the researches. The technique of forming global digital maps of the electrical characteristics of the underlying surface in the very low frequency range points to two main aspects: the formation of information about the electrical characteristics of the continental and oceanic parts of the Earth surface. We obtained the global conductivity map of the continental part of the Earth surface by digitizing the soil conductivity atlas. We calculated a regression function, on the base of which a global map of the dielectric permittivity of the soil has been formed. Using the methods described in the ITU recommendations, we obtained global maps of the conductivity and permittivity of the oceanic part of the Earth surface based on data of the temperature and salinity of the world ocean. With the help of the developed data consolidation algorithm, we transformed the intermediate results into global digital maps of electrical characteristics of the Earth surface in the very low frequency range. 10.18721/JCSTCS.15101 621.371.3 electrical characteristics underlying surface conductivity dielectric permittivity very low frequencies https://infocom.spbstu.ru/article/2022.72.1/ 7-18.pdf
RAR RUS 19-28 Peter the Great St. Petersburg Polytechnic University Suhotskiy Svyatoslav suhotskij2.sa@edu.spbstu.ru
St. Petersburg, Russian Federation
 Zavialov Sergey Peter the Great St.Petersburg Polytechnic University Ovsyannikova Anna anny-ov97@mail.ru
St. Petersburg, Russian Federation
 Peter the Great St. Petersburg Polytechnic University Lavrenyuk Ilya lavrenyuk_i@spbstu.ru
St. Petersburg, Russian Federation
 Symmetrical iterative algorithm for cancelling inter-channel interference of SEFDM signals This article deals with spectrally efficient frequency-division multiplexing signals (SEFDM). Authors considered symmetrical and asymmetrical iterative algorithms to prevent BER performance degradation. These algorithms reduce inter-channel interference (ICI) between the subcarriers, which leads to better value of BER performance. The authors analyzed complexity and results of the algorithms, and determined the best conditions for a symmetrical algorithm with different number of subcarriers and different frequency multiplexing coefficient. 10.18721/JCSTCS.15102 621.391.8 SEFDM demodulation algorithm BER performance feedback on decision https://infocom.spbstu.ru/article/2022.72.2/
RAR RUS 29-39 Ulyanovsk State Technical University Kurganov Sergey sakurganov@mail.ru
Ulyanovsk, Russian Federation
 Ulyanovsk State Technical University Filaretov Vladimir vvfil@mail.ru
Ulyanovsk, Russian Federation
 ANGD-circuits on impedance converters with stabilizing feedback Active electric circuits of arbitrary order with negative group delay (NGD) are proposed, implemented on the basis of Bessel polynomials using impedance converters. The circuits contain operational amplifiers (op-amp), resistors and capacitors. The parameters of the elements are found sequentially from the equations obtained by equating the symbolic and numerical values of the coefficients. At the same time each equation can be solved independently of the others. The stability of the circuits is ensured by the use of an op-amp with internal negative feedback or universal op-amp with external negative feedback. The circuits have the flattest frequency function of the NGD, uniform frequency response and provide non-distorting transmission of voltage pulses over a wider range of durations than the known multi-stage circuits from first-order active circuits. 10.18721/JCSTCS.15103 621.372.54 negative group delay operational amplifier Bessel polynomials impedance converter circuit determinants https://infocom.spbstu.ru/article/2022.72.3/ 29-39.pdf
RAR RUS 40-50 St. Petersburg Electrotechnical University “LETI” Koigerov Aleksey a.koigerov@rambler.ru
St. Petersburg, Russian Federation
 Saint-Petersburg State University of Aerospace Instrumentation Balysheva Olga balysheva@mail.ru
St. Petersburg, Russian Federation
 Finite element simulation of SAW delay line operating with the use of third harmonic frequency A numerical practical approach for a simulation of surface acoustic wave delay line is proposed. The principle of operation of transducers with split electrodes at frequency harmonics is shown. Practical recommendations and calculation algorithm in COMSOL Multiphysics are considered. Admittance parameters were calculated from simulations of delay line employing COMSOL software. Finally, obtained Y-parameters were converted into a full set of S-parameters. The numerical approach makes it possible to accurately model the SAW device using the universal finite element method with automatic inclusion of second-order effects in the device. To demonstrate the finite element method, the frequency response for 1.5 GHz SAW delay line with a relative bandwidth of 7.46 % on 128° YX-cut LiNbO3 are calculated. Input interdigital transducer operates at main frequency, output transducer operates at the third harmonic frequency. The simulation results are in good agreement with the experimental data. 10.18721/JCSTCS.15104 621.37 surface acoustic waves SAW delay line numerical approach finite element method lithium niobate piezoelectric substrate https://infocom.spbstu.ru/article/2022.72.4/
RAR RUS 51-63 Saint-Petersburg Mining University Bazhin Vladimir bazhin-alfoil@mail.ru
St. Petersburg, Russian Federation
 Saint-Petersburg Mining University Masko Olga olgamasko.17@gmail.com
St. Petersburg, Russian Federation
 Evaluating the effect of particulate matter concentration in the furnace exhaust duct on temperature change using a computational fluid dynamics model The technological process of carbothermic silicon reduction in an ore-thermal furnace (OTF) has features that hinder adequate monitoring and control of the entire technological process. High temperature makes it difficult to obtain objective data on melting parameters in the furnace. The main factor contributing to the difficulty of controlling the process is the formation of large volumes of by-product components. Coal and silica dust emissions in the flue gases reach 40–50 % of the finished product – technical silicon. The article is devoted to analysis of dependence of temperature of exhaust gases of OTF silicon production on concentration of solids in them by means of computer simulation. The paper describes the solution of the following tasks: a preliminary assessment of the effect of the concentration of solids on the temperature of the dispersed medium; development of a computational fluid dynamics (CFD) model of the gas exhaust duct of OTF using the ANSYS Fluent software; simulation of the behavior of exhaust gases at different concentrations of silica fume. As a result of analysis of the simulation results, a polynomial dependence of the exhaust gas temperature on the concentration of silica fume in the exhaust gas from the OTF was obtained. 10.18721/JCSTCS.15105 681.518.5 silicon production ore-thermal furnace gas cleaning CFD model ANSYS Fluent temperature silica fume https://infocom.spbstu.ru/article/2022.72.5/ 51-63.pdf
RAR RUS 64-73 Ho Chi Minh University of Education Van Vy vanv@hcmue.edu.vn
Ho Chi Minh City, Vietnam
 Peter the Great St. Petersburg Polytechnic University Gruzdev Alexander gruzdev_spb@mail.ru
St. Petersburg, Russian Federation
 University of Phan Thiet Nguyen Quang Tan tannq@hcmue.edu.vn
Bình Thuận, Vietnam
 Peter the Great St.Petersburg Polytechnic University Nguen Tan Ngoc ngoctan1610@yahoo.com
Polytechnicheskaya, 29, St.Petersburg, 195251, Russian Federation
 Comparison of recommendation systems based on deep machine learning methods Embedding-based models have been used in collaborative filtering over a decade. According to traditional collaborative filtering, the researchers used dot product or similarity measure to combine two or more embeddings. Typically, matrix factorization is the simplest example of an embedding-based model. In recent years, it has been proposed to replace the dot product with deep learning methods, for example, using multi-layer perceptron (MLP) algorithm. This approach is often referred to as neural collaborative filtering (NCF). In this paper, we used NCF in our research, specifically predicting item ratings results and displaying recommendations to users on e-commerce websites. We have applied NCF to the recommender system by using a deep learning model. The article used Olist’s dataset to serve our experiment. We have successfully built a NCF-based recommender system with a large and sparse dataset. We have obtained better results than those produced by other methods. 10.18721/JCSTCS.15106 004.852 recommender system deep learning multi-layer perceptron neural collaborative filtering metric https://infocom.spbstu.ru/article/2022.72.6/