Objective. The use of cold accumulation in cooling systems increases their efficiency, reduces the power of the installed equipment, equalizes the load on the electrical grid and ensures an economic effect. Method. The study is based on the methods of thermodynamic analysis of technical characteristics of various modifications of water-ice cold accumulators. Result. The analysis of technical characteristics of three types of ice accumulators was carried out: with water freezing on the heat-exchange surface (type 1), with water freezing in a tank (type 2) and in containers (type 3). Recommendations for their use were developed and promising areas of scientific research were determined. Specific parameters were compared: volume, cooling capacity and metal consumption. Conclusion. Devices of the second and third types have a number of advantages over devices of the first type: they are more compact, have a metal consumption 1.5–3 times lower. The efficiency of ice accumulators of all types in terms of specific cooling capacity is approximately the same and is within the range of 0.08–0.3 kW/kWh. Accumulators of the third type are of interest. To create them, it is necessary to carry out a set of analytical and experimental studies.

Objective. The aim of the study is to develop a design of a thermoelectric system (TES) for cooling and air conditioning in the passenger compartment of a car, its calculation, analysis of parameters and electrical and thermal characteristics. Method. The study is based on the methods of natural and computational modeling of air conditioning and life support systems in order to find optimal solutions for efficiency, reliability and service life of low-temperature installations, machines and devices. Result. The TES has been calculated and its parameters have been determined. Dependencies describing the main characteristics of the TES and the TEM included in its composition have been obtained. The following dependence graphs have been constructed: changes in the average temperature in the volume of the vehicle cabin, as well as heat exchange systems over time, power, coefficient of performance, TEM supply voltage from the temperature difference between junctions for different values of the supply current, volt-ampere characteristic for different values of the temperature difference between junctions, change in temperature at the cold junction of the TEM from the supply current. The graphs are presented at a temperature of hot junctions of the TEM of 320 K. Conclusions. The parameters of the installation are defined: the number of TEM type TB-199-1.4-1.5 - 18 pcs., the operating power range of a single TEM is from 17 to 40 W with an average temperature difference between the junctions of 50 K, the supply current is from 2 to 6 A with a power consumption of 40 to 130 W, the cooling coefficient is from 0.17 to 0.7.

Objective. Bank card fraud is an increasingly serious problem for individuals, businesses and financial institutions. There is a need for effective fraud detection measures to protect consumers and businesses from financial losses. Method. information-theoretical analysis of methods for detecting fraud with bank cards, machine learning algorithms in improving the accuracy of fraud detection. Result. An analytical evaluation of fraud detection methods is provided, covering different learning approaches: supervised, unsupervised and reinforcement learning. Conclusion. The choice of a fraud detection method should be based on an understanding of the available data, the specific requirements of the application domain and the trade-offs between methods in terms of performance, adaptability and computational complexity.

Objective. The purpose of the work is to determine the features of mathematical models for implementing the competence-based assessment approach. It is necessary to identify which parameters are appropriate to use in the mathematical model, the methodology for their determination, and at what stage the final assessment of competencies is formed. Method. The study is based on the theoretical and information analysis of mathematical models for assessing competencies. Result. The development of a mathematical model for assessing competencies requires taking into account factors, including the labor intensity of the academic discipline, class attendance, participation in Olympiads, conferences, etc. It has been established that competence assessment does not always depend on only one area of knowledge, but is interdisciplinary and includes not only knowledge, abilities and skills, but takes into account the influence of the social, information and intellectual environment. The study showed the prospects of applying the theory of latent variables. Conclusion. The scientific review allows developing a new mathematical model for the competence-based approach to mastering the curriculum. To modernize the competence-based approach, it is necessary to collect information on the extracurricular activities of the student. The result of the competency assessment will be a competency map, formed during the semester or course.

Objective. The article is devoted to the problem of assessing the durability of critical information infrastructure objects in favor of microparametric risk insurance. The feasibility of introducing parametric insurance as a cost-effective way to protect information against threats and the existence of sustainability problems is being supported. Method. The application of reliability theory methods in combination with random function theory allowed to consider the dynamics of stability of operation of the protection object during the period of the action of threats. Result. It was possible to estimate the minimum value of the rating object’s performance and the relevant time of occurrence, which in combination allowed for an assessment of the risk associated with the event. The novelty of the proposed approach is that for cyber risk assessment, a function of the object of assessment was performed, which was formed on the basis of the functions of individual elements of the evaluation object, taking into account its structure and available resources for maintaining functionality. The information security (IS) assessment task for different structures and the Parametric Micro-Insurance Solution Methodologies are described, which focus on the importance of each of their elements as part of the insurance object. Conclusion. he article’s content can be used to set the task of developing methods, models and means for providing IS risk insurance as well as supporting solutions for ensuring sustainability.

Objective. This work examines the problem of fluid flow simulation in a turbulent regime. The main reasons why turbulent flow occurs are due to the existence of high velocities of movement in fluids; besides that, there may be obstacles or changes in the shapes of flows. Method. To determine the characteristics of a flow, it is proposed to use Mathieu’s equation. The main steps of the solution algorithm are presented for Mathieu functions that were used over the course of the computer program execution. Result. Upon evaluating eigenvalues, it is shown that it is necessary to rely on the corresponding transcendental equations. It is illustrated how modified Mathieu functions are calculated. It is indicated how calculations should be carried out in the case of a small parameter value in Mathieu functions. A block diagram of the executed turbulence modeling algorithm is presented. In order to conduct turbulence simulation, a GUI shell based on the Qt library was created in the Qt Creator environment. During the simulation process, the value of the Smagorinsky constant was chosen to be equal to 0.01. For the time step, a length value of 0.05 was selected. During the execution of the simulation, 2000 time steps were used. The simulation results were recorded every 10 steps. The results of the simulation are presented visually. Conclusion. A mathematical model has been created, on the basis of which there are possibilities for modeling turbulent media. The mathematical model has been constructed for various parameters during the flow of solid bodies by turbulent flows.

Objective. The purpose of the research is to synthesize a solution model of an educational organization aimed at automating university management processes. Improving the efficiency of management processes is based on the indicator of the effectiveness of the solution implementation obtained in the work. Method. The process of synthesis of a mathematical model is described, which allows to build a graph of the states of the system and apply the Kolmogorov-Chapman differential equations, as a result, to obtain an indicator of the effectiveness of the implementation of the decision of the head of the university. When carrying out the processes of decomposition, abstraction and aggregation, we obtain a mathematical model of a management decision. Considering the process of solving the control problem in four states of the system, we obtain the Kolmogorov-Chapman differential equations. By setting the normalization equation and applying the Gauss method, we translate the resulting differential equations into linear algebraic equations and find an indicator of the effectiveness of implementing the decision of the head of the university. To achieve automation with the required performance indicator of the solution implementation, it is necessary to obtain the temporary states of the system in question. Result. By linking the obtained indicator with the temporary states of the system, we obtain the effectiveness of implementing the solution of the current system. Subsequently, by solving the inverse problem, obtain the required characteristics necessary for the automation of university management processes. Conclusion. By setting the required performance indicator for the implementation of the solution, we obtain the necessary characteristics for the system in question, which the management processes should have for their further automation. Having the required characteristics, we can make demands on the software and hardware complex and the staff of the university.

Objective. In this paper, the main approaches to modeling the processes of functioning of the organizational and technical system, in particular the processes of maintenance and repair (MRO) of weapons, military and special equipment (VVST) by repair units of the operating organization (EO) using a mathematical model of Markov random processes, which will allow to evaluate the probabilistic characteristics of MRO processes of the VVST at carrying out activities of daily activities, which consist in carrying out work to restore the serviceability of the VST, as well as carrying out maintenance and operation of the OTS. Method. The modeling of processes is based on probabilistic models, in particular, the theory of random processes. Result. The use of a mathematical model of Markov random processes is justified. A graph of the states of the processes for maintenance and repair of VVST has been developed. A decision support system based on PTC Mathcad Prime has been implemented. The averaged generalized statistical information on the reliability of the VST was used as the initial modeling parameters in the work. Conclusion. The results obtained will make it possible to restore the serviceability and operability of the military-industrial complex both at the enterprises of the military-industrial complex and in the conditions of the operating organization without going beyond the time limits established in the regulatory and technical regulations. The considered approaches to modeling the processes of functioning of an organizational and technical system are a powerful tool for making informed and effective management decisions, they allow you to take into account many factors, conduct scenario analysis and optimize solutions, as well as use computers for more accurate and complex calculations.

Objective. When designing complex objects, as well as when it is necessary to perform export-import operations between various computer-aided design systems, the task of automatic correction of drawings becomes quite relevant. Development of a software module for automatic correction of drawings in the AutoCAD system, the need for which is due to reasons such as: the use of different file formats for storing drawings by different CAD systems, the complexity of the drawings. Method. As part of the study, methods of geometric modeling, analytical geometry and graphical presentation of results were used. Result. Algorithms for automatic correction of parameters of position and outline of drawing fragments in the AutoCAD system have been developed, with complexity of O(n) and O(n² ). Conclusion. Analysis of the functionality of the developed module allows us to assert that its use will reduce the time spent when correcting drawings obtained as a result of import from other CAD systems in the AutoCAD system, and improve the quality of design documentation.

Objective. One of the important aspects of maintaining the efficient operation of information systems is the condition of computer equipment. The purpose of the study is to describe a method for effective system analysis of the state of a computer's information storage device. Method. The study is based on the use of machine learning algorithms to analyze and interpret data obtained from SMART tests. Includes a comprehensive analysis and experimental study. It involves conducting experiments with a data set and the Google Colab cloud environment, creating and analyzing a machine learning model, and evaluating the effectiveness and quality of training. Result. A tool for assessing the state of computer equipment based on the Random Forest algorithm has been developed using historical data from SMART tests. Conclusion. The results not only allow the implementation of a working data analysis tool in the field of computer equipment maintenance, but also contain a practical example of increasing the reliability and efficiency of information systems. The results are useful for IT specialists and for organizations optimizing equipment maintenance processes and increasing competitiveness.

Objective. Modern electronic document management systems (EDMS) provide controlled movement of multiple documents along different routes. Successful functioning of EDMS is determined by the availability of a specific document at the right time for a specific user. The purpose of the study is to develop a mathematical model of EDMS that allows determining the indicator of ED availability taking into account the UBI and performing optimization taking into account the complex organizational structure. Method. The study was conducted using the apparatus of Markov processes and the formation of numerical safety indicators. Particular attention is paid to the calculations of the numerical indicator of availability. Result. An important attribute has been determined - availability, the numerical indicator of which allows assessing the general level of a specific EDMS and simultaneously solving many specific problems of identifying and countering threats of information blocking, malicious delay in approval, deviation from established routes, which affects availability and, accordingly, the overall level of security. Conclusion. Known types of applied models (functional, set-theoretic, graphtheoretic, probabilistic-parametric) do not allow explicitly forming availability assessments. The proposed model allows identifying vulnerabilities in the EDMS, which can be used to implement new UBI and contribute to increasing the level of information security in EDMS projects.

Objective. The objective of the study is to formulate and demonstrate potential additional expert capabilities and a hypothesis to improve the quality of technical system projects by combining the analysis of technical characteristics of the project and human factor influence parameters. Method. The paper considers obtaining invariant relationships for some characteristics of technical systems, on the basis of which a hypothesis of the equation of state of a technical system is formulated. Result. Auxiliary analytical approaches have been developed to compare individual operational parameters of projects, conduct an expert assessment of technical systems of projects, devices and technologies. The use of the hypothesis of the equation of state of a technical system allows for expert assessments of the safety of a technical system. Conclusion. The use of additional expert approaches and hypotheses allows for the accumulation of experience in expert assessments, correlation analysis of data, determination of potential capabilities in the context of further modifications and upgrades of technical systems of the project, development of improved operational forecasts and strategies, and adoption of adequate management decisions.

Objective. The aim of the study is to compare and generalize different methods of contactless setting of computer mouse pointer coordinates. Method. To create a contactless human-machine interface, computer vision technologies are used to select a control point on a video camera frame, with the help of which the computer cursor is moved on the user's monitor. General logical methods of scientific research, namely, generalization, are used. An analysis of the considered cursor coordinate control systems is carried out with the allocation of common parts for further generalization and description of formulas for setting the coordinates of the computer mouse cursor. Scientific works with absolute positioning of the computer cursor and works with control of the cursor position shift relative to its coordinates on the previous frame were taken for analysis. Result. As a result of the analysis, strengths and weaknesses of each of the approaches under consideration were indicated. Absolute positioning requires less time to set the cursor to the desired position. It is determined that cursor shift control is not so demanding on the accuracy of calculating the coordinates of the control point. Formulas are given that generalize the methods of moving the computer cursor. Conclusion. The proposed approach to calculating new coordinates of the mouse pointer allows implementing both presented approaches to positioning the computer cursor in the software system, since each of them has advantages depending on the specific situation.

Objective. In decision making when comparing alternatives, it is often necessary to work with different values or estimates that are still important. One of the multicriteria analysis methods that can be applied in the model for determining the vulnerability of cloud computing areas is the ELECTRE I method. This paper presents an algorithm for determining the degree of vulnerability of cloud computing areas using the Electre I method. Method. The Electre I method allows one to evaluate the relative advantages and disadvantages of different cloud computing areas based on a set of criteria. Result. The algorithm presented in the paper includes steps for determining the weights of criteria, evaluating alternatives according to these criteria, and calculating the degree of vulnerability. This model will allow one to determine the area or areas that are most susceptible to the danger of breakdown or failure, and to remove dominated alternatives that do not pose a serious danger. Based on the identified preferences, one can make a decision on troubleshooting the selected areas of the cloud service. An experimental study was conducted on the basis of real data on the cloud computing system. Conclusion. The obtained results confirm the effectiveness of the proposed method and its ability to accurately determine the vulnerabilities of cloud computing areas. The results of this work may be useful for cloud system administrators and security professionals who are concerned about maintaining security and reliability in the cloud environment.

Objective. Substantiation of the expediency of using the proposed methodology for the formation of evaluation materials in the training of IT specialists in the field of programming, followed by its use within the framework of traditional and distance learning technologies in the higher education system. Method. The research methods include: analysis of evaluation materials; methods based on algorithms for decomposing the program code proposed for solving the problem; methods for analyzing data from open sources, methods for analyzing algorithms and data structures. A competency-based approach is used as an alternative to the classical approach, which uses categories of knowledge acquisition. Result. The possibility of using test tasks as traditional ones, as well as tasks in the form of cases, is substantiated. A proven approach to differentiating case programming tasks by level of complexity is proposed, which provides for gradation into three levels. Conclusion. Testing of the methodology has shown its effectiveness in assessing the level of preparedness of students in the field of programming, both in traditional and distance learning.

Objective. The purpose of the work is to make the comparative analysis of the firewall tools for secure systems on the Russian market. The sharp increase in demand for products from domestic developers is associated with the need to abandon the use of foreign information security tools and transition to Russian analogues. Method. Systematization, description and analysis are used as research methods. In this work functional analysis will be carried out in relation to the following solutions: «Universal security gateway «UserGate», security complex «Continent 4», hardware and software complex «ViPNet xFirewall 5», «Firewall with Ideco UTM intrusion detection system». Result. For comparison of firewall tools the following parameters were chosen: functionality of firewalls as network equipment, as means of protection, possibility of clustering, compliance with FSTEC requirements. The analysis of firewall tools showed that the Russian market offers to users worthy analogues of foreign products. However in this solutions some functionality is missing, which indicates the insufficient maturity of the domestic market of firewalls. Conclusion. The choice decision should be dictated by the requirements of a particular organization, based on consumer requests for the functionality or stability of the firewall.

Objective. The aim of the study is to determine the most effective method of semantic analysis of the state of the process of detection, prevention and elimination of consequences of computer attacks. Method. The study was conducted based on the methods of semantic analysis of the state of the process of SOPKA operation. Result. A structural model of the system of semantic analysis of the state of the process of SOPKA operation is proposed, which is capable of providing an analysis of the state of the process of detection, prevention and elimination of consequences of computer attacks. The most effective method for solving the problem of semantic analysis of the state of the process of SOPKA operation is machine learning using ontological modeling. Conclusion. The results indicate the need for further research of the system of semantic analysis of the state of the process of detection, prevention and elimination of consequences of computer attacks.

Objective. To accurately assess the impact of ventilation systems on the acoustic environment of a room, it is necessary to determine the length of the vortex zone that forms as the air flow passes through throttling devices. The article examines the results of modeling a nozzle valve with a variable cross-section during its opening and closing processes. Method. The analysis of airflow formation scenarios at various positions of the control diaphragm was performed using Computational Fluid Dynamics (CFD) in the Ansys Fluent software package. Result. As the cross-sectional flow area decreases, a sharp local increase in airflow velocity is observed, along with the formation of vortex zones and reverse flows resulting from the ejection effect. Conclusion. The presence of complex turbulent flows in the ventilation network leads to increased sound pressure levels and noise penetrating the serviced space. Significant deviations from the recommended maximum velocity, depending on the valve opening scenario, highlight the importance of considering throttling devices in acoustic calculations. Analyzing the length of the flow stabilization section enables optimal placement of the nozzle valve, preventing the vortex zone from breaking up due to the combined influence of local resistances (air distribution devices, tees, bends, and constant airflow valves). To reduce the risk of increased noise, it is recommended to position the nozzle valve on a straight duct section, with a length of at least one duct diameter before and three duct diameters after the throttling device.

Objective. This study provides a review of organic additives, organic and inorganic binders, including air and hydraulic lime binders. Heat and mass transfer in the processes of decarbonization and carbonization of air and hydraulic lime binders and repair and restoration compositions based on them is considered, knowledge of which is necessary for the design of equipment and technological processes for the production of mineral binders, as well as technologies and compositions for repair and restoration work. Method. The dissociation and decarbonization reactions are given as reversible reactions, the decomposition front, the boundaries of limestone decomposition, the dissociation time and the dissociation reaction rate are calculated. To obtain complete information on mass transfer during the decarbonization of limestone, heat transfer is also taken into account, which complicates the task due to the nonisothermal temperature field, which affects the difference in the rates of the decarbonization reaction. Result. The solution of the problem, carried out by Held and Ivanov, and the Fourier differential equation of thermal conductivity are given. The types of lime hardening are considered: carbonate, hydrate and hydrosilicate. Carbonate hardening of lime is presented as a hardening process that takes a long time. The mechanism of carbonate hardening has been studied. The dependence of carbonization intensity on water content and humidity was revealed. Conclusion. The scientific and practical value of a new scientific direction has been established: “Research of air and hydraulic lime binders and the development of repair and restoration compositions based on them.” As a result of the research, new compositions have been developed for the repair, restoration and restoration of historical and cultural monuments that meet the repair and restoration requirements.

Objective. The paper presents general equations of the moment theory of a shell of zero Gaussian curvature taking into account creep deformation. The problem of the stress-strain state of a shell is considered, with the boundary conditions: rigidly fixed at the base and free edge at the top. The cylinder is subject to internal hydrostatic pressure. Method. A linear non-homogeneous differential equation of the fourth order with respect to deflection is obtained. The solution is given in the MATLAB software package. The non-linear MaxwellGurevich equation is used as the equation of state between creep deformations and stresses. To determine creep deformations, a linear approximation of the first derivative with respect to time (Euler's method) was used. Result. The calculation of the shell made of secondary PVC was performed using the grid method. The method was tested. A program for calculation in the MATLAB package was developed with the possibility of varying the initial data and outputting a graph of the dependence of stress displacements on time. During creep in the shell, circumferential stresses increase by 14.7%. Conclusion. The proposed approach can be applied to the analysis of the stress-strain state and bearing capacity of a reinforced concrete shell as well. There are no restrictions on boundary conditions and the type of loading, and the beam material can be not only polymers and composites for construction purposes, but also concrete.

Objective. The aim of the study is to study the mechanism of chemical interactions with subsequent formation of new formations in the structure of concrete stone; undisclosed possibilities of modifying the matrix system with organic and mineral additives; development of filled highly active binders; use of enriched fillers of high quality; a combination of concrete, reinforcement and dispersed reinforcement, contributing to the evolution of the development of modern concrete science. Method. Research is carried out in accordance with regulatory documents GOST 12730.3–2020 Concrete. Methods for determining water absorption; GOST 10180-2012 Concrete. Methods for determining hardness using control samples; GOST 12730.1-78 Concrete. Methods for determining definition. Result. The complex use of organic and mineral additives was studied, which contributed to the accelerated formation of the structure and strength of the stone without the use of heat. An improvement in rheotechnological characteristics has been recorded, a water-reducing effect has been established, and an increase in the shelf life of the concrete mixture has been established, which is no less important when concreting large-sized structures or transporting semi-finished products over long distances. Conclusion. The proposed research results will make it possible to successfully implement projects of global importance, creating stable, strong and durable concrete structures.

Objective. The objective is to develop a unified method for solving a general nonlinear boundary value problem associated with discontinuous phenomena, which allows identifying all the characteristic features of the behavior of thin-walled systems under load. The issues of nonlinear deformation, loss of stability of the initial equilibrium shape and post-critical behavior are considered using the example of a thin spherical shell. Method. The problem is solved by numerical and analytical methods, representing a set of methods of catastrophe theory and the finite difference method of increased accuracy. The main attention is paid to the mathematical aspects of the phenomena under consideration. Result. The parameters of the stressstrain state of subcritical, critical and postcritical deformation are determined using a spherical shell as an example. The relationships between the limit and bifurcation values of the load parameters are obtained, allowing us to determine the group of the limit state of the achieved level of the stress-strain state of the structure. Conclusion. The solution of the general problem allows us to obtain complete and necessary information to determine the degree of danger of the states of structures and ensure their reliability.

Objective. To identify patterns in changes in the properties of building mortars obtained from dry building mixtures (DBM) depending on the dosage of redispersible polymer powders (RPP), the composition of the complex mineral additive (CMA) and the duration of hardening in air-dry conditions. Method. The studies were conducted in accordance with the regulatory documents: GOST 31356–2013 Dry building mixtures on a cement binder. Test methods. GOST R 58277-2018 Dry building mixtures on a cement binder. GOST 31108-2016 Test methods, general construction cements. Specifications. Result. The presence of RPP in the composition of DBM leads to an increase in the flexural strength when kept for up to 120 days in air-dry conditions and an increase in the adhesion strength to the base. The greatest adhesion strength is observed in compositions with fly ash. The introduction of RPP and the composition of the MKD have an insignificant effect on increasing the modulus of elasticity. A positive effect of RPP in increasing the flexural strength limit during prolonged hardening of the mortar in air-dry conditions was revealed. The effect of RPP on the rate of hardening of the mortar at an early age was noted. Conclusion. Replacing part of the natural mineral raw materials with technogenic waste and using RPP will increase the environmental and economic efficiency of the production of SSS and ensure the production of mortars with the required properties.

Objective. The aim of the study is to develop refined methods for calculating structures on deformable foundations. To achieve this objective, the problem of constructing refined dependencies between stresses and strains in a physically nonlinear material taking into account crack formation is considered. Method. The use of refined mechanical and mathematical models will allow not only to obtain more reliable results of the operation of the "structure - foundation - deformable base" system, but also to correctly solve the engineering problem of designing reinforcement and the leveling process. Result. To design the reinforcement of the basement and upper parts of the structure, mechanical and mathematical modeling of the process of tear-off line formation with increasing forces in jacks was performed based on a physically nonlinear statement of the problem and the use of refined physical dependencies for a thin layer in which there is adhesion between the superstructure and the foundation. The requirements for a mechanical model of the process of detaching a building from the foundation with increasing forces on jacks are substantiated. Conclusion. The main physical dependencies that determine the process of formation of the tear line in the adhesion layer are formulated, and also take into account the structural nonlinearity associated with the change in the calculation scheme during the gradual tearing of the building from the foundation.

Objective. The article considers the operational features of beam structures with one-way ties. Method. By studying the operational features of beam structure supports, analytical and graphical dependencies between beam displacements and their support reactions are derived. The properties of generalized functions are used to describe the nonlinearities that occur during structural deformations. Differential equations for transverse bending of beams are presented, taking into account nonlinearities and methods for their solution. Result. Design and calculation schemes have been developed that take into account the operation of beam structure supports, allowing us to obtain precise values of deflections and internal forces of sections on this basis, which ensures the necessary reliability of the structure. The results are given in the form of analytical expressions, graphs, and tables. Conclusion. Calculation models of beams with one-way connections can find wide application in the design of beam structures with supports with one-way connections.