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

In this paper, the problem of extrapolating a video signal with a quasi-rational spectral density, which significantly generalizes the rational density, is explicitly solved. The spectral characteristic of video signal extrapolation is constructed using the original method of A.M. Yaglom, a follower of academician A.N. Kolmogorov, who first posed the problem of extrapolation for random sequences and processes. The essence of the method consists in transferring all studies and calculations of spectral characteristics and densities from the real axis to the complex plane. The paper considers a video signal with a quasi-rational spectral density of a special type, interesting for practical applications, in which, as shown by the author using the Chebotarev and Sturm methods, it has all its roots only in an open upper half-plane.

Keywords: random process, video signal, prediction, filtering, spectral characteristic, prediction time

Experimental studies have been conducted in a hydroacoustic pool on the propagation of an amplitude-modulated signal of a complex shape for communication with underwater objects based on a parametric antenna. The parameters of the hydroacoustic pool are given, the modulation and demodulation modes of hydroacoustic signals are developed. The bit error rate is estimated for each measurement, it is proven that the experiment was carried out under strictly controlled parameters, namely, in the absence of currents, noise and reflections (hydroacoustic pool), the receiver is accurately installed and ideal synchronization of the signal is ensured. There were no unwanted phase and frequency deviations of the transmitted signal, as well as time delays between the transmitter and receiver.

Keywords: hydroacoustic, parametric antenna, communication, amplitude-modulated signal

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

This article presents the results of experimental study of the strength of wood and concrete specimens under local buckling by a flat die under short-term loading action. At joint operation of a reinforced concrete slab and a timber beam in the connection there is buckling of timber and concrete elements, therefore it is necessary to know values of strength at these types of loading of timber and concrete. The strength values of timber, concrete on expanded clay aggregate, compression and buckling strength ratios of materials, as well as physical properties of materials according to the requirements of normative documents have been determined. The values of timber deformation were obtained and the graph of deformation dependence on stresses and graphs of deformation growth were plotted; the coefficient of soil stiffness was obtained to determine the strength for local crushing of materials

Keywords: short-term loading, strength, flat die, compression, buckling, coefficient of subgrade reaction, timber, concrete

The paper describes the features of construction and monitoring in cultural and historical heritage areas using the example of the railway bypass of the Inkerman St. Kliment Monastery. The analysis of the current regulatory documents regulating activities in this area is carried out. The stages of geomonitoring are described. The geodetic component of monitoring is considered, taking into account the requirements established by the current legislation.

Keywords: geomonitoring, construction, cultural heritage site, leveling, railway track, deformation grade, precipitation and deformations

The considered virtual simulator model, based on an automated approach, provides tools for studying user actions in conditions of interaction with complex systems or objects. This, in turn, provides a basis for a thorough analysis and identification of typical and unique mistakes made during training or work.

Keywords: aviation simulators, development of simulator systems, flight instrument equipment simulators

The paper proposes a solution to geological problems using probabilistic and statistical methods. It presents the results of using spectral correlation data analysis, which involves the processing of digital geoinformation organized into three-dimensional regular networks. The possibilities of applying methods of statistical, spectral, and correlation analysis, as well as linear optimal filtering, anomaly detection, classification, and pattern recognition, are explored. Spectral correlation and statistical analysis of geodata were conducted, including the calculation of Fourier spectra, various correlation functions, and gradient characteristics of geofields.

Keywords: interprofile correlation, self-adjusting filtering, weak signal detection, geological zoning and mapping, spatially distributed information

The article discusses the sources and types of data used to create a digital student profile, as well as possible ways of using them in educational analytics. A digital profile is a comprehensive description of a student's academic, behavioral, and social characteristics collected from various sources. The data coming from educational institutions' information systems, social networks, instant messengers, mobile applications, video content platforms, questionnaires, and video cameras are analyzed. The importance of a digital profile is due to its ability to support personalization of learning and improve the efficiency of educational processes. The article highlights numeric, categorical, binary, ordinal, and unstructured data types, as well as metadata and derived data used for data analysis in DataScience and machine learning algorithms. Examples include grades, participation in educational events, social activity, preferences, text comments, and video recordings. Attention is also paid to the analysis of possible ways of using this data to predict academic performance, identify learning difficulties, and assess student engagement and motivation.

Keywords: digital student profile, educational analytics, data types, data sources, data analysis, personalization of learning, machine learning in education, datascience, educational data mining, crisp-dm, semma

The article discusses the development of data normalization and standardization tools using Python libraries. A description of the theoretical foundations and formulas used to normalize and standardize data is considered. For internal calculations of the developed software, the Pandas and NumPy libraries were used. The external interface was built on the basis of the Streamlit library, which allows you to deploy web applications without any additional resources. Code fragments are provided and implementation mechanisms are explained. A description of the developed tool is provided: a detailed explanation of the functionality of the tool, user interface and examples of use. The importance of data preprocessing, selection of an appropriate method, and final remarks on the usefulness of interactive data processing tools are discussed.

Keywords: data processing, statistics, information systems, Python web systems.

During the production of delicatessen canned fish, the control system should ensure a gentle heat treatment regime with a decrease in the degree of temperature exposure to the product. Changing the modes requires reconfiguration of the type and parameters of temperature regulators in the autoclave, carried out based on the results of processing modeling. The software complex for modeling the object and control system during pasteurization provides for calculating the degree of sterilizing effect. The complex contains system and application softwares. The application modules implement the functions of a graphical interface, a virtual controller, numerical simulation of product temperature changes and data transmission. The virtual controller allows select controllers: positional, proportional-integral-differential, and states. The novelty of the model lies in the display and the possibility of changing both the parameters of the regulator and the coefficients of the desired polynomial, taking into account the sign of the derivative of temperature during heating and cooling. The practical value of the work is to reduce the time for reconfiguring the autoclave control system, ensuring a reduction in the degree of temperature exposure when a given sterilizing effect is achieved by selecting the type and parameters of temperature control rules.

Keywords: software complex, modeling, control system, pasteurization, canned fish, regulator, temperature