In the article, based on the estimate of the Euclidean norm of the deviation of the coordinates of the transition and stationary states of the dynamic system, the compression condition of the generalized projection operator of the dynamic system with restrictions is derived. From the principle of contracting mappings, taking into account the derived compression condition of the projection operator, estimates are obtained for the sufficient condition for the stability of the dynamic system of stabilization of the equilibrium position and program motions. The obtained estimates generalize the previously obtained results. Ensuring the stability of the operator of a limited dynamic system is demonstrated experimentally.

Keywords: sufficient condition for stability, projection operator, stabilization of equilibrium position. stabilization of program motions, SimInTech

This article discusses two of the most popular algorithms for constructing dominator trees in the context of static code analysis in the Solidity programming language. Both algorithms, the Cooper, Harvey, Kennedy iterative algorithm and the Lengauer-Tarjan algorithm, are considered effective and widely used in practice. The article compares these algorithms, evaluates their complexity, and selects the most preferable option in the context of Solidity. Criteria such as execution time and memory usage were used for comparison. The Cooper, Harvey, Kennedy iterative algorithm showed higher performance when working with small projects, while the Lengauer-Tarjan algorithm performed better when analyzing larger projects. However, overall, the Cooper, Harvey, Kennedy iterative algorithm was found to be more preferable in the context of Solidity as it showed higher efficiency and accuracy when analyzing smart contracts in this programming language. In conclusion, this article may be useful for developers and researchers who are involved in static code analysis in the Solidity language, and who can use the results and conclusions of this study in their work.

Keywords: dominator tree, Solidity, algorithm comparison

The purpose of the article is a software implementation of a module for analyzing the activity of site users based on a heat map of clicks, compatible with domestic web services, for example, combining the functionality of correlation and regression analysis and visualization in the form of dashboards before and after making changes to site elements. All functionality is carried out directly in the web analytics service. Based on the data obtained on the analyzed site element, a decision is made to adjust the design and/or content to increase the click rate. Thus, the proposed solution allows us to expand the functionality of the web analytics service and reduce labor costs. The software module has been successfully tested. As a result of the analysis and making the necessary adjustments to the site, the click rate increased

Keywords: user activity, correlation and regression analysis, dashboard, program module, trend line, coefficient of determination

The article considers the possibility of modeling the random forest machine learning algorithm using the mathematical apparatus of Petri net theory. The proposed approach is based on the use of three types of Petri net extensions: classical, colored nets, and nested nets. For this purpose, the paper considers the general structure of decision trees and the rules for constructing models based on a bipartite directed graph with a subsequent transition to the random forest machine learning algorithm. The article provides examples of modeling this algorithm using Petri nets with the formation of a tree of reachable markings, which corresponds to the operation of both decision trees and a random forest.

Keywords: Petri net, decision tree, random forest, machine learning, Petri net theory, bipartite directed graph, intelligent systems, evolutionary algorithms, decision support systems, mathematical modeling, graph theory, simulation modeling

This article analyzes the main causes of fatal injuries in the construction industry of the Russian Federation and a number of other foreign countries, including falls from heights, electric shock, injuries associated with the use of construction machinery and mechanisms, as well as exposure to harmful substances. In conclusion, the article highlights the importance of joint efforts by employers, employees and regulators to create a safer and healthier work environment in the construction industry. The implementation of the preventive measures described in the article can significantly reduce the risk of accidents and improve the well-being of employees.

Keywords: construction industry, industrial injuries, accidents, causes of injuries, working conditions, occupational risks, working at height, occupational safety, environmental factors, workplace organization, training

The work presents the review of modern log trucks under the recent sanctions imposed. The author states that the problem of renewing the existing log trucks becomes urgent for forest transporting and logging companies nowadays. There is a wide range of new basic chassis and trucks at the market to build log trucks with a wheel formula 6x4 and 6x6 produced by Russian, Belorussian and Chinese factories. A great number of trailer links is produced to build log trucks. There is an opportunity to buy used trucks of other companies. For the first stage of the technical and economic analysis and preliminary selection of the optimal type and composition of a logging truck, a comparative assessment of the effectiveness of logging trucks was carried out. The analysis shows that Russian log trucks with engine power more than 400 HP (horsepower) can compete with the best foreign models. Nevertheless, the problem of reliability of Russian, Belorussian and Chinese log trucks needs further research.

Keywords: log trucks, trailer links, productivity, effectiveness

In operational diagnostics and recognition of states of complex technical systems, an important task is to identify small time-determined changes in complex measured diagnostic signals of the controlled object. For these purposes, the signal is transformed into a small-sized image in the diagnostic feature space, moving along trajectories of different shapes, depending on the nature and magnitude of the changes. It is important to identify stable and deterministic patterns of changes in these complex-shaped diagnostic signals. Identification of such patterns largely depends on the principles of constructing a small-sized feature space. In the article, the space of decomposition coefficients of the measured signal in the adaptive orthonormal basis of canonical transformations is considered as such a space. In this case, the basis is constructed based on a representative sample of realizations of the controlled signal for various states of the system using the proposed algorithm. The identified shapes of the trajectories of the images correspond to specific types of deterministic changes in the signal. Analytical functional dependencies were discovered linking a specific type of signal change with the shape of the trajectory of the image in the feature space. The proposed approach, when used, simplifies modeling, operational diagnostics and condition monitoring during the implementation of, for example, low-frequency diagnostics and defectoscopy of structures, vibration diagnostics, monitoring of the stress state of an object by analyzing the time characteristics of response functions to impact.

Keywords: modeling, functional dependencies, state recognition, diagnostic image, image movement trajectories, small changes in diagnostic signals, canonical decomposition basis, analytical description of image trajectory

The research aimed to investigate the properties of glass-basalt composite tubes, specifically examining the relationship between structural fractal dimensions, composition, and mechanical properties. Physical experiments were carried out to assess the properties of glass and glass-basalt composite tubes. These tests included measurements of tensile strength, modulus of elasticity, fracture resistance, flexural strength, and additional mechanical characteristics. Fractal analysis of rovings and epoxy binder was performed at the microstructural level to evaluate the impact of structure on mechanical performance. Through predictive modeling of the physical and mechanical properties of glass-basalt composite tubes, an optimal range of properties was identified. This range is defined by specific technological parameters: rovings content of 68–74%, basalt fiber diameter of 7–12 μm, and epoxy binder content of 21–27%. Within this framework, the production of tubes with the following target properties was predicted: tensile strength, compressive strength , and modulus of elasticity.

Keywords: fractal modeling, microstructure, matrix fibers, glass-basalt plastic, composite material, forecasting, strength, fractal dimension, heterogeneity, mechanical properties, composite pipe, glass fiber, basalt, correlation analysis

Currently, one of the most extensive issues in the field of information security is the organization of user access control to information infrastructure objects. Taking into account the volume of corporate information resources, as well as the number of users requesting access, there is a need to automate the access approval process taking into account possible risks. In this case, the most optimal solution to this problem is the use of fuzzy logic. The article analyzes the process of providing access to the information infrastructure using a fuzzy classifier and develops a conceptual model of the fuzzy classifier algorithm for incoming requests for access in order to automate the process and minimize information security risks associated with possible destructive actions aimed at the confidentiality, integrity and availability of the information infrastructure.

Keywords: neural network, machine learning, information security, cybersecurity, properties and structure of a neural network, mathematical model, threats and information vulnerabilities

A complex dynamic system is defined by a structurally invariant operator. The operator structure allows formulating problems of stabilizing program motions or equilibrium positions of a complex dynamic system with constraints on state coordinates and control. The solution of these problems allows synthesizing a structurally invariant operator of a complex dynamic system with inequality-constraints on the vector of locally admissible controls and state coordinates. Computational experiments confirming the correctness of the synthesized structurally invariant projection operator are performed.

Keywords: structurally-invariant operator, stabilization of program motions, complex nonlinear dynamic system, projection operator, SimInTech

The composition of the lightweight plaster mix includes the following components: hydraulic binder, crushed volcanic tuff-scoria (as a fine lightweight filler), reinforcing fiber and synthetic additive. The hydraulic binder consists of Portland cement and finely ground volcanic tuff. Plaster mixes based on volcanic tuff are in demand in regions with a warm or sharply continental climate: high temperatures during the day or low at night, including Ethiopia. The purpose of the research presented in the article was: to form material structure models that allow evaluating the material properties and evaluating the solutions obtained during the implementation of an active experiment. As a result of the experiment, optimal values ​​​​of the main components of the plaster mix based on volcanic tuff were established, which is present in the mixture as a light fine filler and as a component of the hydraulic binder. Modeling of the material structure and engineering interpretation of its properties were carried out.

Keywords: plaster material, tuff-scoria, pozzolanic activity, mathematical modeling, analytical optimization

Bamboo as a building material has its own characteristics. It works well in stretching and bending. Bamboo has only longitudinal fibers that are prone to splitting, however these fibers are twisted in a knot. This phenomenon reduces the tensile strength. The mechanical properties of bamboo describe its reaction to physical influences. In general, bamboo has a high tensile strength parallel to the fibers. This article describes the mechanical properties of a bamboo rod depending on the loads, as well as modulus of elasticity of various types of bamboo. This article summarizes the experience of building buildings made of bamboo elements.

Keywords: bamboo, fibers, knot, joint, strength, construction, deformation, stretching, mechanical properties, anisotropic material

The article discusses the planning and commissioning of an autonomous field located on permafrost. Most of the oil and gas fields are located in permafrost areas. The development of such deposits is costly, as it creates the need to prevent the thawing of permafrost. Commissioning works are the final stage of construction and installation works. The CW is difficult in conditions of permafrost. In permafrost conditions, problems may arise with starting the installed equipment.

Keywords: commissioning, permafrost, field, installation, drilling, oil industry, oil and gas industry, project, freezing, maintenance

This article examines the security of currently popular corporate instant messaging applications (messengers). A comparative analysis of the security of some solutions for corporate use has been carried out. The main result of the review is the conclusions about the advantages and disadvantages of the considered systems, which can be used by organizations to choose the appropriate solution.

Keywords: Information security, corporate messenger, messaging, internal communications, instant messaging systems, end-to-end encryption

The article discusses the results of the analysis of the stress-strain state of the junction of the column and the beam of a monolithic reinforced concrete frame - in particular, the cornice nodes of the outer columns, which have an L-shape. In these nodes, part or all of the tensile (upper) reinforcement of the beam, bending along a certain radius R, passes into the column. The subject of the study is the stress state of concrete in the frame node, as well as the features of the operation of the curvilinear section of the tensile reinforcement. The study of the features of the concrete operation was carried out by setting up a computational experiment. Modeling was performed in the Lira-SAPR software package. The characteristics of the model (finite element scheme) and the main results of the calculation are given - the distribution and numerical values ​​of stresses. To assess the actual work of the tensile reinforcement of the node, an analysis was made of the influence of the loading history of the reinforcement bar - its plastic bending to give the required outline. It was established that the stress state of concrete of a bisecting section differs fundamentally from the stress-strain state of concrete in normal cross-sections of a beam and a column. Taking into account the loading history of the reinforcing bar (preliminary inelastic bending) allowed us to conclude that, with the same tensile force, the deformations of a pre-bent bar exceed the deformations of a rectilinear bar. Obviously, this circumstance leads to an increase in the crack opening width.

Keywords: ramny node, reinforced concrete, reinforcement, stresses, deformations, bisector section, normal section, plastic bending, bending radius, loading history, finite element, Lira-SAPR