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  • Optimization of radio resources and state transition intensity in a dual-service 5G network model with elastic traffic type

    5G wireless networks are of great interest for research. Network Slicing is one of the key technologies that allows efficient use of resources in fifth-generation networks. This paper considers a method of resource allocation in 5G wireless networks using Network Slicing technology. The paper examined a model for accessing radio network resources, which includes several solutions to improve service efficiency by configuring the logical part of the network. This model uses network slicing technology and elastic traffic. In the practical part of the work, transition intensity matrices were constructed for two different configurations.

    Keywords: queuing system, 5G, two - service queuing system, resource allocation, Network Slicing, elastic traffic, minimum guaranteed bitrate

  • A mathematical model of a heat exchanger for energy-efficient industrial systems

    The work is devoted to the development and research of a heat exchanger for a contact gas-liquid heat exchanger. To increase the efficiency of heat transfer, the surface receiving heat is equipped with longitudinal fins and transverse partitions that form vortex structures in a turbulent gas flow. The expected decrease in gas temperature is 300-600 °C when cooled with water at a temperature of 50 °C. Simulation modeling has been carried out, including analysis of temperature distribution and hydraulic resistance, thermal power and stresses.

    Keywords: heat exchanger, efficiency improvement, exhaust flue gas, heat recovery, mixing heat exchanger, numerical modeling, mathematical model, pixelation method

  • Development of a new mathematical method for modeling a modified design of a radial sliding bearing

    The article is devoted to the development of a new mathematical method for modeling radial plain bearings having a polymer coating with an axial groove on the bearing surface. For the calculation evaluation of technical solutions for wear resistance, the compressibility of a truly viscous lubricant under laminar flow conditions is taken into account. As a result, new mathematical models were obtained that make it possible to estimate the duration of the hydrodynamic flow regime of the lubricant, to prove the stability and possibility of changing lubrication modes from boundary to hydrodynamic, as well as to make a calculated assessment of the effect of compressibility of the lubricant and wear resistance on operational characteristics.

    Keywords: modeling, mathematical method development, modified design, compressibility impact assessment

  • The problem of detecting faces in a video stream: a review of technologies

    With the rapid development of technology and the widespread use of video surveillance, modeling the architecture of neural networks for human recognition in video is attracting increasing attention from researchers. This article presents a study of the use of neural networks (NN) as an interdisciplinary model for classifying objects in video, including solving the problem of face search. This highlights the versatility of neural networks in integrating trained data and accurately classifying objects, which is critical for ensuring security and efficiency of video surveillance. The study uses an analysis of various neural network architectures, as well as a study of their operating algorithms. Data obtained from a literature review and experimental results allow us to evaluate the effectiveness of solving the task of classifying objects in video using various architectures, without tying the study to a specific data set. The study confirms the possibility of using modern neural network architectures for human recognition in real-time video based on the experience of experts in the field of computer vision and machine learning. The active use of neural networks as a tool for video surveillance increases the safety of infrastructure facilities and the efficiency of security services. Ultimately, this article presents an analysis of neural network architectures for facial recognition in video streams, advocating their use as a key element in the development of modern video surveillance systems and ensuring public safety.

    Keywords: neural networks, neural network architectures, video surveillance systems, real-time recognition, improving security, social well-being

  • Study of self-compacting concrete properties with microsilica and grinded concrete crush as a complex additive.

    The article presents results of self-compacting concrete with microsilica and grinded concrete crush additive study. The work presents concrete mix designes and mechanical tests results.Found that with the use of complex additive it is possible to obtain concrete of class B80 with a strength of at least 60 MPa after 7 days of hardening under normal conditions. High frost resistance of such concrete is noted. Concluded the possibility of complex additive application and potential advantages of its usage in self-compacting concrete.

    Keywords: self-compacting concrete, silica, active mineral additives, concrete crushing screening, concrete, concrete scrap, finely ground filler, secondary filler, construction waste, determination of mechanical characteristics of concrete, high-strength concrete

  • Reprocessing of wood and polymer waste to obtain a composite material for building thermal insulation

    The paper presents the results of experiments on the production of a composite material using small-lump wood waste based on soft wood varieties and waste products from non-plasticized polyvinyl chloride. An additional component of the raw material mixture was methylene chloride, in which polymer waste was dissolved. The solution was mixed with the filler, and then the solvent was pressed and removed at its boiling point. It is established that an increase in the degree of filling of the studied material contributes to the formation of a developed porous structure. The effect of increased porosity on the main operational properties, primarily thermal conductivity and water resistance, has been revealed. It is determined that the degree of filling, equal to 55 wt. %, makes it possible to obtain a material with the most effective combination of values of basic properties for use as a building thermal insulation. The practical application of the results of the work makes it possible to produce a low-cost thermal insulation material due to the joint disposal of heterogeneous waste.

    Keywords: polymer composite material, thermal insulation material, polymer waste, wood waste, polyvinyl chloride, methylene chloride

  • The use of expanded perlite waste in the composition of a composite binder

    The possibility of using expanded perlite dust (RUNWAY) in cement binder systems is being considered. A method for modifying the binder by joint mechanical activation of Portland cement, alumosilicate waste and hyperplasticizer is presented. The physico-chemical features of the modified runway make it possible to regulate the processes of hydration, phase formation, as well as the formation of the structural matrix of the composite. The compressive strength of the binder using RUNWAY as an active mineral additive increases by 36% with a decrease in density.

    Keywords: technogenic raw materials, perlite, binder, dispersion, modification, mechanical activation, hydration, structure formation, phase formation, resource conservation

  • An approach to filling in gaps in data on the operation of a hydraulic unit

    The paper provides a brief overview of publications on the application of mathematical modeling methods in the study of the patterns of functioning of hydroelectric power plants (HPPs). In particular, the following are considered: mathematical models of the total minimum water consumption for a cascade hydropower system in China; a mathematical model of hydropower plants; a mathematical model of two small hydroelectric power plants operating in tandem; accurate modeling of hydraulic transient characteristics in a complex drainage system. The task of filling in the gaps in the data concerning the operation of hydroelectric power plants is formulated. The approach to its solution is proposed to be based on the use of the method described in previous publications by one of the authors and based on the use of regression analysis apparatus. The specific task of filling in data gaps for a hydroelectric unit of one of the Siberian hydroelectric power plants has been solved. The following factors are used: active and reactive power of the electric generator, voltage, current and temperature of the stator iron, rotor current, air cooler hot air temperature.

    Keywords: hydroelectric power plant, electric generator, data gaps, predictive analytics, regression model, adequacy criteria

  • Development of a tool for visualizing data on site user activity

    One of the most important points in increasing the conversion component of a web resource is identifying the most attractive places for the site user. To identify these locations, a site user activity data visualization tool was created that provides a visual representation of each user action on a site page.

    Keywords: heat map, site, oculograph, fixation, priority area

  • Projection operator of minimization and maximization of a linear functional with restrictions on the vector of admissible program motions

    The paper presents the formulation of problems of minimization and maximization of a linear functional with inequality constraints on the vector of admissible program motions and equality constraints specified by a linear manifold. An analytical solution is synthesized that determines the projection operator for solving the specified mathematical programming problems with equality constraints and inequalities. An analytical solution is obtained that determines the boundary values ​​of the Lagrange multiplier for the synthesized projection operator. The correctness of the obtained solution is illustrated.

    Keywords: mathematical programming, linear functional, projection operators, admissible program motions, stabilization of program motions, SimInTech

  • Model of a digital twin of the control and flaw detection system of mechanical transmissions

    The article considers a variant of constructing a digital twin model for diagnostics of operation of a mechanical gear transmission - a reducer consisting of a pair of cylindrical gears. The basis of the considered digital twin model is an adaptive learning vibration mathematical model of the static operating mode when gears rotate at a constant speed. The vibration signals of the reducer, recorded by accelerometers and effective for detecting and diagnosing faults, are used as the main information measured at the facility. The detected faults are cracking, wear, chipping and pitting of teeth. A special feature of the implemented digital twin is the ability to simultaneously detect faults of several teeth at once, both on the driving and driven gears, by time and frequency characteristics, as well as the ability to determine the main technical data of a specific reducer by vibration characteristics.

    Keywords: diagnostic mathematical model, digital twin, vibration diagnostics, mechanical gearbox, tooth defect, diagnostic signal, vibration power spectrum, synchronously averaged time characteristic

  • Forecasting flood inundations on the rivers of Siberia using the example of forecasting the water level in the Iya River (Eastern Siberia) based on a multifactor regression model

    In the work, based on the previously constructed multifactor dynamic regression model of water level in the Iya River (Eastern Siberia), the authors forecast this indicator for June 2023 in three options: pessimistic, optimistic and neutral (base). A comparison of the forecasting results with the actual value of the water level confirmed the high adequacy of the model and good prospects for its future successful use to solve a wide range of applied and practical problems.

    Keywords: regression model, river water level, lag time, seasonal variable, forecast, adequacy, criteria

  • Application of computer modeling to calculate the size of the effective focal spot of a microfocus X-ray tube

    The article considers the solution of the urgent problem of calculating the size of the effective focal spot of a microfocus X-ray tube using computer modeling methods. The principle of operation of the calculation method used by the authors is to compare interference images obtained using tested microfocus X-ray tubes with simulated interference patterns formed using the developed software by numerically solving the wave equation. It should be noted that modeling a one-dimensional interference pattern using fast Fourier transform requires a significant amount of RAM and takes considerable time even when using modern computer equipment. The paper presents the results of modeling phase contrast profiles for two types of test objects – nylon fishing line and aluminum wire. The considered method for determining the size of the focal spot is characterized by good sensitivity and allows efficient and high-precision calculations for all types of microfocus X-ray tubes.

    Keywords: computer modeling, X-ray tube, microfocus source, focal spot, non-destructive testing

  • Reconstruction of the school's spatial planning solution using the example of a building in the KBR

    The public education project ""Dream School"", implemented in support of the federal school overhaul program, attracts students of architectural and design schools in the regions, which will allow them to simultaneously acquire applied competencies in the learning process. During the development of the design project, the need for specialists to conduct a preliminary design analysis was revealed, since one of the five schools did not meet the standards in terms of their spatial planning parameters. It is proposed to carry out the reconstruction of this educational institution. The premises of the dining room and the assembly hall are transferred to the annex block.

    Keywords: school design project, school renovation, school recreation, public education project "Dream School", school reconstruction

  • A comparison of machine learning libraries for introducing artificial intelligence into CRM system

    This paper analyzes the performance of solving the classification problem using various open-source artificial intelligence and machine learning libraries in the field of marketing and customer relationship management; based on the results of experiments, the best library is selected for the purpose of introducing artificial intelligence into domestic CRM systems based on numerical performance indicators.

    Keywords: artificial intelligence, machine learning, big data, classification, marketing, customer relationship management, import substitution, open source