The article considers variants of arrangement of various reactive power compensation devices, the choice of location of which took into account both modes of operation of power grids and voltage levels in the nodes. Mathematical modeling made it possible to form an optimal calculation algorithm based on a multi-criteria approach, taking into account the possible voltage increase at the corresponding substations. However, this approach is accompanied by some increase in active power losses, so the final conclusions should be based on expert procedures.

Keywords: reactive power compensation, mathematical modeling, installation site, power losses, multi-criteria approach, calculation algorithm, power system, substation, compensating devices

The article describes the well-known design of a tape-shell foundation. Based on the analysis of the known design, a number of factors affecting the limitation of the scope of the tape-shell foundation are derived. In order to ensure the controlled inclusion of the reinforced concrete shell of the foundation in the work, the author of the article proposed the use of a damping gasket under the tape support contours. A gasket made of an easily compressible slab material - polystyrene foam - is compressed under the influence of the load from the walls and columns of the basement of the building, the reinforcement of the shell is stretched and involves the soil of the subshell part of the foundation. At the same time, the strength characteristics of the band-shell foundation increase, the sediment decreases. The author of the article conducted numerical studies to determine the required thickness of the gasket. It is proved that the use of a damping gasket is relevant for soils with a deformation modulus of less than 15 MPa, above this value, the use of a gasket is impractical.

Keywords: tape-shell foundation, reinforced concrete shell, tape support contour, ground whole, auxiliary method of inclusion in the shell, damping gasket, thickness of the gasket

When creating a model of a nonlinear electrical system based on differential equations, it is important to keep in mind that ordinary differentiation does not give an adequate mathematical idea of ​​the nonlinear physical processes taking place. Even in the simplest case of a conductor with a current, the construction of an adequate model is only possible if the tensor approach is applied. From this point of view, any electrical system is an object of tensor methodology. A typical example of a non-linear electrical system is an AC electromagnetic drive. The nonlinear nature of the processes in such devices is due to a number of reasons. The main reasons are: current displacement in the winding of the AC electromagnetic drive and saturation of the steel of the magnetic circuit in the process of magnetization. Both phenomena admit tensor description, which is confirmed by the research presented in the article.

Keywords: dynamic characteristic of magnetization, electromagnet, mathematical model, tensor methodology

The issues of ensuring the reliable operation of bearing production on the basis of the organization of the process monitoring system (SMTP), based on the introduction of effective automated control and diagnostics of technological equipment, including processing modes and technical condition, active control of product quality in the manufacturing process, output characteristics of rings processed by the eddy current method, as well as making decisions on timely maintenance of equipment. The results of the inspection are stored in a report file generated in the eddy current device computer: information about each checked part is stored: the time of inspection, the type of part, the surface to be monitored, the number of the machine on which the part was processed. The results of eddy current control serve as the basis for monitoring the dynamic characteristics of the equipment by vibroacoustic vibrations. Based on the results of the control within the framework of the SMTP, a decision is made on the quality management of processing. The introduction of SMTP provided a significant reduction in ring defects in terms of grinding quality up to 2-3 % and increased operational reliability of bearings.

Keywords: grinding process monitoring, bearing rings, dynamic machine quality, active control, eddy current control, ring quality

An urgent scientific and technical task is the development of electric energy converters with high operational and energy characteristics. The use of modern methods for the development and analysis of power electronics circuits based on the use of computer equipment allows us to successfully solve this problem. In this article, a schematic diagram of an alternating voltage regulator has been developed, in which a control system based on a microcontroller implementing an algorithm for pulse-phase regulation of the variable output voltage is used to control a power thyristor key. The control system, a power thyristor key, is synchronized with the moments of transition through zero of the supply voltage of a sinusoidal shape. The controller circuit is adapted for computer modeling in the environment of the PROTEUS software product. In the article, a block diagram is also developed and a software implementation in assembly language of the microcontroller operation algorithm is performed. As a result of computer modeling, time diagrams of voltages on the main elements of the AC voltage regulator circuit are obtained. Time diagrams explain the features of electromagnetic processes occurring in the controller circuit. The results of computer modeling, the controller circuit, the developed algorithm and the microcontroller software can be used in the development of electric energy converters for automatic control systems of electrical equipment.

Keywords: computer simulation, thyristor regulator, alternating voltage, microcontroller operation algorithm, time diagrams, transistor switch, control system, damping circuit, power thyristor, active-inductive load

This article briefly discusses recurrent neural networks and bidirectional recurrent neural networks. A conditional random field is also described. In particular, we consider the vector representation in the form of the ELMo model, the bidirectional language model and its fine-tuning. A diagram of the architecture of a bidirectional recurrent neural network with CRF is also given.

Keywords: named entity recognition, neural network, word vector representation, language model, conditional random field, neural network architecture, recurrent neural network, natural language processing, bidirectional recurrent neural network

Traditional analytical methods for determining critical forces lead to difficult solutions of transcendental equations, therefore they are not universal and are ineffective for rods with complex design schemes. The proposed numerical-graphical method for determining critical forces, can be easily adapted to complex non-classical problems.

Keywords: Euler problem, rod, critical force, stability, differential equations, boundary conditions, finite difference method, eigenvalues

The main types of formwork systems used in monolithic construction are described. The types of formwork by construction, by the type of concreted structures, by the base material, by turnover, as well as the types of formwork during concreting under different temperature conditions are considered. The historical reference of the appearance of the formwork is given.

Keywords: formwork, frame-monolithic construction, structures, vertical, horizontal, large-panel, small-panel, block, volume-adjustable, heating, inventory formwork

This article discusses the algorithms used for the operation of the chatbot. Within the framework of these algorithms, a general approach to the operation of dialog systems is considered. And the algorithm of the dialog system is proposed, based on a general approach, which includes a natural language processing module. The algorithms that will be applied to the chatbot to search for products of interest to the user are also presented. Among the considered algorithms are such as the algorithm of interaction between the user and the chatbot, the processing of user requests and the algorithm of natural language processing. A modified algorithm for natural language processing is also presented, taking into account the necessary requirements.

Keywords: chatbot, natural language processing, user request processing, named entity recognition, dialog manager, dialog system

Based on the Bayes approach, a representative number of experimental measurements was determined when assessing the quality of the environment, in particular, when monitoring the quality of the atmosphere and checking the compliance with the standard for the accumulation of solid municipal waste

Keywords: Bayesian approach, quality control, experimental measurement, a priori data, a posteriori data, distribution density

The purpose of this work is to develop an algorithm for recognizing shrinkage defects on metal alloys. The steps for image processing are described. When analyzing the algorithm, a description is presented for each step, followed by a software implementation. The final step, after using the methods of the algorithm, is to count the contours of the defects. To demonstrate the functionality of the software, random photos of the metal body in the section were taken, where defects in the form of gas pores can be directly observed. The software, with the correct selection of input data, processes the image with high accuracy, minimizing errors in calculating defects. Using the proposed algorithms reduces the diagnostic time. The article presents a comparative description of the manual and automated methods, showing the effectiveness of the second method in comparison with the first. To write the software, the Python 3.7 programming language was used, as well as the OpenCV computer vision algorithms library.

Keywords: defect detection, computer vision algorithms, OpenCV, metal defects, shrinkage defects

The choice of the installation location of compensating devices is determined by various factors that must be taken into account when performing calculations. The location of reactive power compensation devices is determined based on the results of mathematical modeling and the optimal operating mode of individual sections of electrical networks. The paper presents the results of modeling, considers the uncertainties encountered in solving the problem of placement of compensating devices.

Keywords: compensating devices, electric power industry, active power losses, minimum reduced costs, uncertainty, power gain, optimization criteria, electrical node, damage vector, optimization

A model of passenger traffic movement is proposed that is suitable for identifying hidden patterns in the processes of passenger flow creation. The passenger flow is divided into four components, for which separate passenger flow submodels are developed: quasi-deterministic passenger flow from leaving stops to points of mass attraction of passengers; stochastic hourly passenger flow from each arrival stop to different districts of the city; stochastic flow that models the distribution of passengers between final stops in accordance with the degree of popularity of stops; chaotic distribution of passenger traffic between stops with a small number of daily visits. The results of calculations of the quasi-deterministic passenger traffic submodel from leaving stops to points of mass passenger attraction are estimated.

Keywords: passenger transport, passenger traffic models, passenger behavior patterns, modeling

The study is devoted to the analysis of satellite observations data assimilation to discover the necessary information for developing and verifying mathematical models of hydrodynamics and biological shallow-water kinetics. The use of satellite earth sensing data is taken to enhance information base. The possible use of neural networks with optical flow computation is considered in the study. The objective of the study is to develop a software tool used to identify the initial conditions in mathematical modeling of hydrobilogical shallow-water processes. The article illustrates the relevance of applying the observational data processing from satellite earth sensing. There are considered the necessity and possibility of using the neural network approach with the optical flow computation in solving problems of information processing from gray-scale snapshots.

Keywords: mathematical modeling, shallow water body, satellite sensing data, neural network, contour, image processing

The paper is devoted to the analysis of methods of adoption of satellite observation data in order to identify the required information used in the development and verification of mathematical models of hydrodynamics and biological kinetics of shallow water reservoirs. For the information accumulation, we consider the use of remote sensing data. The aim of the paper is to identify the best implementation method for software tools in order to improve the quality of assimilation of date of satellite sensing of the Earth relating to hydrobiological processes in a shallow water reservoir. The results of the work indicate the clarity and relevance of the use of high-tech methods for filtering ERS images. The modern methods of accentuation of contours of objects based on discontinuities in the brightness of a halftone image, used in real time or time close to it, have been considered, and their algorithms have been briefly described.

Keywords: mathematical modeling, shallow water reservoir, satellite sensing data, filtering methods, Kirsch, Sobel, LoG, LBP, operator, recognition, contour