The work is devoted to the study of the temperature distribution and equivalent voltage on the surface of a thermal radiation receiver during experimental and computational series. The experiments showed a qualitative and quantitative coincidence of the temperature data obtained by thermal imaging with the results of numerical modeling. The average error was 0.5℃, with a maximum deviation of 1.5℃ at individual points, which is due to edge effects and thermal insulation features. The computational model reproduces the main characteristics of the temperature field, including the effect of shielding, using a relatively low density of the computational grid. As part of the verification of the numerical model, the analysis of grid convergence was carried out, as well as the control of residuals and control of solution parameters were performed.

Keywords: heat exchanger, numerical and analytical calculation, convective and radiant heat transfer, efficiency improvement, outgoing flue gas, heat recovery, gas-liquid heat exchanger, numerical modeling, mathematical model, ANSYS Workbench software

In the process of ensuring information security, an important element is the protection of data from malicious influence. One of the stages of protection is to identify the source of the threat. The source of the threat may be the attacker himself, acting through his own user profile. Detecting and identifying a malicious profile in this case is a key element of building protection. In the context of user profiling, well-researched systems are social networks. Learning Management Systems (LMS), despite their similarity to social networks, remain devoid of scientific attention. Due to the similarity with social networks and the increasing introduction of learning management systems into information structures, this type of system is becoming a vulnerable point. There are several approaches and methods for detecting malicious activity, including statistical methods, machine learning methods, and rule-based methods. Our proposed approach combines a rule-based system with machine learning algorithms to improve the accuracy of detecting malicious activity. A rule-based system provides a detailed view of potential anomalies, while a machine learning algorithm provides a more detailed view of specific attacks. This paper highlights the aspects of determining malicious activity and user profiling in learning management systems and provides an example of one of the methods.

Keywords: information security, information system, social network, learning management system, user profiling, malicious behavior, classification

The article describes the main problems associated with the principles of calculation and design of building structures of buildings and structures in seismically active areas in accordance with the provisions of the regulatory document SP 14.13330.2018. The difficulties that may arise when using foreign regulatory requirements in terms of design and calculation are noted. The calculation of a flat steel multi-story frame for the main and special combination of loads and impacts is considered. The frame calculation for a special combination is performed according to SP 14.13330.2018 with and without taking into account the additional requirements of foreign design standards ASCE / SEI 7-22, ANSI / AISC 341-22. The requirements of foreign standards were not taken into account in full, but only in terms of increasing the reliability of the structure, for certain positions. The change in the parameter of the frame metal consumption for various calculation options is analyzed. Conclusions are formulated and recommendations are given on how to reduce the metal consumption when calculating for seismic impact, taking into account the increase in the reliability of building structures.

Keywords: finite-element schemes, columns, crossbars, seismic action, steel frames, flat frames, design, limit states, material consumption, optimization, reliability, special combinations, combination factors

The article considers one of the problems hindering the use of ceramic piezoelectric materials based on the BiFeO3 - BaTiO3 phases, which is caused by high values ​​of the dielectric loss tangent of these materials. It is assumed that this is due to different electrical conductivity of individual grains of this type of piezoelectric ceramics (Maxwell-Wagner effects), caused by the presence of iron ions in their composition, which have different oxidation states. In order to equalize the oxidation states of iron ions found in the grains of the considered ceramics, we used annealing of its samples in an atmosphere formed as a result of thermal decomposition of ammonium carbonate. It was found that this technique allows: a) to reduce the values ​​of tgδ of the CPM by 6 - 7 times; b) increase the polarizing field strength by at least 40%, and the value of the longitudinal piezoelectric modulus to 140 pC/N.

Keywords: piezoelectric material, electrical conductivity, dielectric loss, defect, iron ions, Maxwell-Wagner effect, reducing atmosphere, ammonium carbonate

Abstract: This article is devoted to the formation of a methodology for determining the duration of emergency recovery work, in case of damage to buildings and their structures from the effects of force factors, which is an important industrial and social task. The main indicator adopted in this article for calculating the duration is the duration criterion (Upr). In the course of the study, factors were formed and grouped according to segmental characteristics, based on the degree of their influence on the duration of emergency recovery operations, a multiple regression equation was compiled, which allowed taking into account the influence of the most significant factors on a single assessment scale. The findings of the study are supposed to be used to determine the duration of emergency recovery work. Thus, the methodology for determining the duration of work is an important tool in the complex of measures for the effective conduct of restoration work and minimizing costs.

Keywords: emergency recovery work, organizational and technological model, method of expert assessments, multiple regression equation, capital construction project, technical condition of the building, force impact, ranking, duration of emergency recovery

The paper presents the results of the survey of consoles of precast reinforced concrete columns of an industrial building under construction. The consequences arising from errors during the manufacture of columns, as well as the method of calculating the console are described. The survey was carried out in order to detect the position of the reinforcement in the consoles of reinforced concrete columns. When performing a survey of the technical condition, the following tasks were set: to determine the actual condition of the supporting structures, their mating nodes at the time of the survey, to establish the actual reinforcement of the structures, to give recommendations for the restoration (strengthening) of the bearing capacity of the column consoles.

Keywords: inspection, load-bearing capacity, concrete, column, reinforcement, strengthening

The article proposes an approach to determining the level of developer brand protection, which is understood as the reputation of the developer in relation to the regional market, formed in the Internet. The level of protection of the developer's brand takes into account the Gunning Nebula Index of text reviews about the developer, the average volume of words in text reviews about the developer, the number of negative text reviews about the developer, the total number of text reviews about the developer and the degree of competitiveness of the real estate market in the region. Estimates of the level of brand protection of developers in Perm and Yekaterinburg are given and analyzed. To reduce reputational risks and increase the level of brand protection, if it is not high enough, developers are recommended to regularly collect positive customer feedback, conduct brand protection audits, collect and classify negative feedback into true and false. True negative reviews should be discussed with customers, address the cause of the negative review, and then invite customers to remove or correct the negative review. When dealing with false negative reviews, you should seek their removal or publish detailed reasoned rebuttals to them online.

Keywords: real estate developer, online reviews, Gunning Nebula Index, brand protection, degree of competitiveness in the market, reputational risk management

The paper presents the study of sound conductivity of a promising building material “Corrugated veneer”, the sequence of the study is presented, the installation for the study of sound conductivity is developed, the sound absorption and sound conductivity coefficients of the material “Corrugated veneer” are obtained.

Keywords: wood materials, finishing materials, building materials, board materials, veneer, laminated wood

The paper presents the results of the survey of the reinforced concrete monolithic foundation of a ball mill with central unloading. The consequences of errors made during the construction of the foundation of machines with dynamic loads, as well as the foundation monitoring methodology, are described. The survey was carried out due to an increase in the vibration level of the equipment installed on the foundation and the detection of foundation defects in the form of cracks and chips in concrete. When performing the technical condition survey, the following tasks were set: to determine the actual condition of the supporting structure at the time of the survey, to establish the physical and mechanical characteristics of the materials of the structure, to indicate the characteristics and dimensions of damage sufficient to determine the volume of repair and restoration work, to develop recommendations for further safe operation of the structure.

Keywords: inspection, bearing capacity, foundation, dynamic load, concrete, reinforcement, strengthening

Modernization of university campuses in the context of the development of domestic higher education and science to increase the technological sovereignty of the country is one of the pressing problems of modern domestic architecture. The article examines the main factors that determine the need to modernize existing university campuses and influence its capabilities and tools. Based on the analysis of these factors, the main modern requirements for campus modernization are formulated.

Keywords: modernization, university campus, modernization factors, modernization requirements

The article deals with the problem of determining the volume of traffic on streets with irregular transport demand. The analysis of the historical dynamics of urbanisation of the cities of the Russian Federation is carried out. Various types of layouts of educational institutions (school and preschool) are considered, taking into account their capacity and percentage distribution in cities of the Russian Federation. The sample size of respondents for conducting a sociological survey is calculated. The results of the study are presented taking into account the age group, the method of delivery of students, the distance of residence from the places of attraction, etc. The correlation dependence of traffic intensity and population density through the power of the points of attraction of the urban environment is clarified using calibration coefficients obtained from the results of a sociological study through mathematical processing. A comparative assessment of the dependencies before and after calibration according to the criteria of reliability and representativeness was performed.

Keywords: urban urbanization, traffic intensity, irregular traffic, points of attraction of the urban population, sociological research

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

The article is devoted to the problem of optimizing the provision of resources in organizational systems, taking into account the factors of an aggressive external environment. The main task is to develop a model that will reduce costs when providing resources under various criteria and restrictions. The author proposes to use mathematical modeling to solve this problem. It examines various modeling and optimization approaches, including the use of linear and nonlinear functions, consideration of time and other parameters such as time, weather and possible risk. The article also discusses specific models of the external environment that can be used when calculating the effectiveness of the “Resource Provision - External Environment” system. In conclusion, the author suggests that the proposed approaches will help improve understanding of optimization processes and application of models in real-world settings.

Keywords: providing resources, mathematical modeling, optimization, risk management, organizational systems, external environment.

Equipping roads with communications is complicated by the almost complete lack of roadside infrastructure, including power lines, as well as difficult terrain. When emergencies occur on this kind of country roads, residents are forced to seek help from nearby settlements that are well-connected. Therefore, providing suburban routes with communications is a key social task. Using an existing base station as an example, this article calculates the attenuation and propagation range of a radio signal for LTE technology and GSM technology, provides a comparative analysis, and uses methods of mathematical modeling and system analysis.

Keywords: LTE, GSM, Okumura-Hata model, Lee model, Longley-Rice model

This work is devoted to the study of the possibility of determining heart diseases on the basis of 13 categorical and numerical signs. We present a detailed analysis of the dataset, including dividing the data into training and test samples, dividing features into numerical and categorical, applying 4 different classification algorithms, checking the quality of the model using two techniques – delayed sampling and cross-validation. To assess the quality of the model, we pay attention to the value of the recall metric and the error matrix built on the test dataset from the deferred sample or on each test fold when using cross-validation. The results of the study are important both for a deep understanding of the relationship between certain medical indicators and heart disease, and for the development of effective methods for predicting them in the presence of individual symptoms.

Keywords: cardiovascular diseases, classification task, quality metrics, cross-validation, recall, machine learning, random forest