No. 6 (2022)

The article is a generalization of some of the author's works, prepared by him both individually
and in collaboration with colleagues. The article shows how graph theory can be applied, it would
seem, in such diverse areas as education and sports. In the first case, the graph model is used to formulate
and solve the problem of compiling optimal test tasks (tickets). It is formulated as a problem of cutting
(partitioning) the graph G (N, R) into subgraphs. The original graph G(N, R) is divided into a given
number K of subgraphs where the same topic. The peculiarities of the formulation of the given problem
give rise to many heuristic algorithms for its solution. The following heuristic is considered in the article:
each test task is formed sequentially, and each next question is placed in the current test task if its
score is the closest to the relative value of the difference between the average complexity of test tasks
and the total complexity of those questions that are already included in this test task, to the amount of
questions left to include in the task. Algorithms and results of their software implementations are presented,
with the help of which studies were carried out on the optimal formation of test tasks designed to
control the knowledge of trainees. Various heuristics are analyzed that allow optimization of test tasks.
In the second case, it is shown that tournament tables for sporting events can also be represented by
graph models. Formally, the task of drawing lots, as in the case of the formation of test tasks, is reduced
to the task of splitting the graph into subgraphs, each of which will correspond to one of the groups in
the tournament table. In addition, each vertex of the graph corresponds to the rating of a certain participant
in the tournament. The edges of the graph show the relationship between the participants – the
presence of an edge indicates that the corresponding participants are representatives of the same association
or club. Based on these models, descriptions of the developed algorithms and the results of their
software implementations for the optimal formation of tournament tables used in competitions on the
example of table tennis are given. Heuristics are analyzed for one- and two-criteria optimization of
tournament tables construction. The commonality and continuity in the algorithms for the formation of
tournament tables and the sequential distribution of questions in test tasks is to use not only graph models,
but also the same analytical relationships to formalize the heuristics used.

A modeling approach has been developed for materials based on organic semiconductors
and their physicochemical and gas-sensitive properties. For modeling, such methods as multiple
linear and non-linear regression, neural networks were used. As an input vector for modeling the
properties of metal-containing polyacrylonitrile are the parameters of the technological process of
forming materials: the mass fraction of the alloying component (cobalt) in the film-forming solution,
technological modes of IR annealing: temperature, time of the first and second stages. Output
vector - functional characteristics and physical and chemical properties of materials (resistivity,
gas sensitivity coefficient, stability and selectivity). Abstract—Metal–carbon systems with Co metal
particles based on polyacrylonitrile have been synthesized by IR pyrolysis. The resistance values
were measured in the medium of the detected gas (chlorine). Modeling of the functional characteristics
and physicochemical properties of materials was carried out on the basis of data obtained
from the study of 200 samples of cobalt/polyacrylonitrile films. Multiple linear regression proved to be effective for predicting resistivity values. Neural networks are used to predict the gas
sensitivity coefficient, selectivity, and stability of cobalt-containing polyacrylonitrile films.
An artificial neural network in the form of a multilayer perceptron was built to predict the gas
sensitivity coefficient of gas sensor elements based on the data of technological processes for obtaining
material (mass fraction of the alloying component (cobalt) in the film-forming solution,
technological modes of IR annealing: temperature, time of the first and second stages). Compliance
of the synthesized model was checked: with experimental data: correlation coefficient
R=0.82, root-mean-square error st=0.017. The synthesized models satisfactorily describe the collected
data within the experimental error, which makes it possible to optimize the chemical composition
and heat treatment conditions.

The paper considers the software-modeling complex of the power grid management system and
its elements. The relevance of the work is due to the requirements of the current legislation for forecasting
electricity consumption to solve the problem of maintaining a balance of capacity between
the generating side and electricity consumption. The developed algorithms and control methods are
used as part of a software-modeling complex for managing the power grid and power equipment, the
most relevant is the use of autonomous consumers and micro-grids in local power systems. For the
effective conduct of experimental research, an experimental methodology was developed, including
the stage of development of the experimental plan-program; the choice of means of conducting the
experiment; conducting the experiment; processing and analysis of experimental data. It is shown
that it is possible to use the technical and information basis of a hierarchical automated information
measuring system for monitoring and accounting of electricity to build a technological management
system of a regional grid company. It is shown that the smart meters of the intelligent electricity metering
system (ISU) are in continuous communication with the producer and consumer of energy, that
is, monitoring takes place in real time. The developed neural network model (NS) model reduces the
task of short-term forecasting of power consumption to the search for a matrix of free coefficients by
training on available statistical data (active and reactive power, ambient temperature, date and index
of the day, predictive estimates of power consumption of the forecasting model, some connections, the
power system of the magnitude of the consumed active and reactive power has an acceptable level of
prediction error. A neural network has been developed to estimate the capacity, calculate and predict
the temperature of the cores of a power cable line in real time based on data from the temperature
monitoring system, and taking into account changes in the current load of the line. The analysis of
the obtained characteristics showed that the maximum deviation of the data received from the neural
network from the data of the training sample was less than 3%, which is quite an acceptable result.
The comparison of the forecast values with the actual ones allows us to speak about the adequacy of
the chosen network model and its applicability in practice for the reliable operation of the cable system
of power supply to consumers. The analysis of the results showed that the more the insulation
material of the power cable line is aged, the greater the temperature difference between the original
and the aged sample.

The article considers the stability of the Poincare–Steklov filter both from the point of view
of the theory of four-poles and from the point of view of iterative numerical methods for solving a
system of linear algebraic equations. HIL simulation involves splitting the initial system into parts, with one part being modeled numerically on a computer, and the second part is represented by a real
physical object. The parts of the system exchange data with each other through a hardware-software
interface, which can be implemented in different ways and should ensure stability, as well as convergence
of the results of HIL simulation to the results of modeling the original system. The variants of
constructing software and hardware interfaces ITM, TLM, TFA, PCD, DIM, GCS and the Poincare-
Steklov filter are described in the relevant literature sources. At the first stage, the article formulated
in a generalized form the problem of analyzing the stability of a system divided into parts using the
Poincaré-Steklov filter. The parameters of this system are found. At the second stage, the analysis of
the stability of the system divided into parts was carried out both from the point of view of the theory
of quadripoles and numerical methods for solving a system of linear algebraic equations. At the next
stage, the article presents the results of numerical modeling of the initial and partitioned system in
MATLAB. When modeling in parts, the parts of the system exchanged data with each other at each
step of the simulation only once with a delay of h. This method of numerical modeling of a system
divided into parts is as close as possible to the processes occurring during HIL modeling of systems.
A comparison of the obtained simulation results of the initial and fragmented system allowed us to
conclude that the Poincare-Steklov filter, with the correct choice of values of stabilizing parameters,
allows for stability and convergence of the results of HIL modeling of systems, and can also easily
ensure the stability of the results of PHIL modeling.

Quantification in collective behavior and decision-making in fuzzy conditions is crucial to
ensure the health and safety of the population. The task of modeling and predicting behavior in
fuzzy conditions, as is known, has increased complexity due to a large number of factors from
which an NP-complete multi-criteria problem is formed. There is a difficulty in quantifying the impact of fuzzy factors using a mathematical model. In this regard, the paper proposes a stochastic
model of human decision-making to describe the empirical behavior of subjects in an experiment
simulating an emergency scenario. The developed fuzzy model combines fuzzy logic into a
conventional model of social behavior. Unlike existing models and applications, this approach
uses fuzzy sets and membership functions to describe the evacuation process in an emergency
situation. The purpose of this work is to define fuzzy rules and analyze existing solutions. The scientific
novelty lies in the formation of a set of factors that form fuzzy rules for making dynamic
decisions. The problem statement in this paper is as follows: to form a set of factors affecting the
behavior of pedestrians, which are modeled as fuzzy input data. The practical value of the work
lies in the creation of a new set of fuzzy rules that allows them to be used in the evacuation algorithm
for the effective solution of the task. The fundamental difference from the known approaches
is in the application of a new set of fuzzy rules, which contains factors: perception, intention, attitude.
To implement the proposed model, the process of social behavior during evacuation, independent
variables are determined. These variables include measurements related to social factors,
in other words, the behavior of individual subjects and individual small groups, which are fundamental
at an early stage of evacuation.

Modern computationally intensive tasks of mathematical physics require continuous increasing
of the performance of computer equipment used for their highly efficient solution. However,
at present, the development of their electronic components is slowing down due to limitations
of technological production and operational processes. One of the ways to overcome the computer
productivity growth crisis is the development of digital photonic computers (DPC). In the paper
we suggest a promising DPC architecture, which consists of a functional subsystem, data stream
synchronization and switching subsystems, and photonic-electronic interfaces of data exchange
with external devices. We describe the principles of each subsystem. The functional subsystem is a
set of DPC devices that provide 64-bit floating point arithmetic logic operations (according to the
IEEE754 standard), implemented as linear pipelines with processing of least significant bits forward.
The synchronization subsystem provides a single rate of data flow among various functional
devices of the DPC, combined into a computing structure. According to the topology of the computing
structure, the switching subsystem controls the data streams at the stage of DPC programming
or during processing according to conditional transitions. For data exchange between the
DPC and external devices, we suggest the technology of serialization of low-frequency parallel
channels and deserialization of high-frequency serial channels. We give a theoretical evaluation of the performance of the computing structures implemented on the DPC, which is similar to the
structures of mathematical physics problems concerning processing of special matrices. We show
that DPCs, due to their clock frequency, can provide the performance that exceeds the performance
of microelectronic devices by two and more orders of magnitude.

Analysis calculating large sparse unstructured matrices (LSU-matrices) methods and tools
for cluster computing systems with a traditional architecture showed that for most tasks of processing
matrices with about 105 rows, performance compose reduced 5-7 times compared to the
peak performance. Meanwhile peak performance of computing systems is mainly estimated by the
LINPAC test, which involves the execution of matrix operations. The main goal of the work is to
increase the efficiency processing LSU-matrices, for this purpose advisable to use reconfigurable
computing systems (RSC) based on FPGAs as the main type of computing tools. For efficient processing
LSU-matrices on RCS, a set method and approaches previously described in the papers
are used, such as the structural organization of calculations, the format for representing
LSU-matrices "row of lines", the paradigm of discrete-event organization of data flows, the method of parallelization by iterations. The article considers the method of parallelization by basic
macro-operations for solving the problem of processing LSU-matrices on RCS, which implies
obtaining a constant computational efficiency, regardless of the portrait of processed LSUmatrices.
Using developed methods for processing LSU-matrices for reconfigurable computing
systems makes it possible to provide computational efficiency at the level of 50%, which is several
times superior to traditional parallelization methods

On the base of global technological tendencies analysis the needs for strategic analysis
methods and technological trends are defined. It is pointed out that the effective task decision must
be complex and must support information, logical and methodical interconnection for the following
stages: the monitoring, the technological trends forming and structuring and the technological
and technologies priorities estimation. The main complexity in the priorities estimation is in getting
quantity estimates, criterion interaction and opposite connections in technological trends
analyses. The general approach to solve the problem is suggested. The logical interconnected
procedure for priorities estimation is proposed based on the analytic hierarchy process (AHP) and
the analytic nets method (ANM). The formal scheme to transfer from a technological trend of a
subject sphere for transformed dynamic technology graph is designed. The technologies join the
real as well as the virtual parts. The procedure for criteria forming is discussed. The detailed description
for trends priorities estimation is presented. The main attention is made to criteria and
technologies interconnection problem. The AHP and ANM using to decide estimation problems is
discussed. The suggested procedure practical realization is described be means of an example.
The example reflects the main problems of quantity estimation for technological trends priorities such as criteria and technologies interconnection. The procedure constructed now is used for the
strategic analysis and estimation for innovation development of high technologies enterprises,
road cards making and technological forecasting in various spheres.

The work is devoted to the study of the possibility of optimizing the process of synthesis of
gesture classifiers by selecting the most significant channels of electromyographic (EMG) activity
of the muscles of the forearm. The first part of the study is devoted to the development and analysis
of the performance of gesture classifiers with a different number of EMG channels, ranked by
significance based on the Pearson criterion. The solution of the problem of classification of gestures
by EMG signals was first implemented on the basis of ensembles of decision trees trained by
the gradient boosting method. For this, software was developed that allows automatic synthesis
and training of gesture classifiers. Next, a series of studies was carried out to find the optimal
number of EMG channels based on three criteria: the classifier learning rate, the performance of
the trained model, and the area under the ROC AUC error curve. To do this, a cycle of training
and testing of the classifier was carried out for data sets recorded at different positions of the electrodes
on the forearm. Then, range diagrams of the studied criteria were constructed for various
numbers of EMG channels involved in the work from 1 to 8, ranked by significance in each of the
samples. It was found that the optimal number of EMG channels involved under the experimental
conditions was 3-6, since a further increase did not lead to a decrease in the classification error,
while significantly degrading the performance. The proposed method allows you to automatically
select the channels, the electrodes of which are located above the most informative areas of the
forearm in case of an accidental change in the position of the sensors. The second part of the work
contains the results of a full-scale experiment to demonstrate the possibility of controlling a
wheeled robot through EMG analysis.

The purpose of the research is to determine the area of setting the argument τ and its discretization
intervals when constructing an algorithm for adaptive nonlinear
optimal smoothing of multi-parameter data of trajectory measurements, which makes it possible to
jointly implement the spatial and temporal redundancy of the data obtained. The research was
carried out by constructing a Λ-orthogonal basis function in order to obtain independent estimates
for the coefficients of the smoothing polynomial. It is shown that it is advisable to solve the problem
of determining the maximum likelihood estimate of the coefficient vector of the smoothing
polynomial by the method of successive approximations. When constructing a Λ-orthogonal basis
function, the maximum likelihood estimate of the coefficient vector of the smoothing polynomial is
achieved in 2-3 iterations. It follows from the research results presented in the paper that the accuracy
index Qт as a function of two arguments ( is the smallest value of the argument and Δτ is
the discretization interval of the argument τ) in a wide range of values of these arguments changes
slightly, but increases sharply at . In this case, the values of these arguments should not
exceed, respectively, the maximum and minimum possible numbers that can be written without loss
of accuracy in the re grid of the computer used. With a uniform discretization step of the argument τ it is advisable to choose the argument in the middle part of the interval¸where and
respectively, are the minimum and maximum numbers that can be written into the bit grid of a
computer without loss of accuracy. In case of adverse conditions Approaching the edges of the
interval can lead to an increase in calculation errors in determining the secondary parameters of
the position of the aircraft due to the fact that the main matrix of the system of equations becomes
ill-conditioned.

In this paper the basic methods of determining the coordinates of cylindrical objects to control
the geometric parameters of an object with a regular structure are considered. Predominantly
the considered methods are used in determining the parameters of fuel rods (installations) of fuel
assemblies at a nuclear power plant. The purpose of this work is to analyze the existing methods
for determining the geometric parameters of objects with regular structure. To achieve this goal, it
is necessary to solve the following problem - to compare and conduct a study of existing methods
for determining the geometric position of objects with a regular structure and to identify their measurement based on a particular method. Comparative analysis included a description of existing
contact and non-contact methods (measurements of linear dimensions of three-dimensional
objects, measurements of geometric parameters of an object in space and a device for its implementation
and three different methods of controlling linear dimensions of three-dimensional objects
by three Cartesian coordinates). The following tool was used for the determination - the object
under study was photographed by one video camera on a radiation-resistant CCD from two
defined points in space. The image points of the object were identified on the obtained images.
Then, using the data on atomic rector dimensions and video camera parameters, we calculated the
spatial coordinates of the object points in the object coordinate system and the elements of external
orientation of the images. The approximate values of the unknowns needed to solve the problem
were determined in advance, using the methods known in photogrammetry. The analysis
showed that the most effective are non-contact methods based on processing images of the scene
formed by video cameras based on mosaic photodetectors. Thus, measuring systems based on
television sensors (video cameras) are the most expedient for measuring the height difference of
an ordered sequence of cylindrical objects. The considered mathematical model has allowed to
define a methodical error of measurement of geometrical parameters by reconstruction of a threedimensional
scene on a series of images in conditions of the non-contact definition, caused by
imperfection of the defined measuring method or the simplifications admitted at measurements.
On the basis of the obtained data, it is possible to determine the center of gravity of the fuel assembly
head, for which the methodological error is minimal, and, accordingly, to take it as a basis,
relative to which to calculate the height difference of all steel heads of fuel assembly.

This work belongs to the field of hydroacoustics, namely to the problem of digital
beamforming based on spatial fast Fourier transform (FFT) in a multibeam echo sounder
(MLS) with baseband digital signal processing. The applicability of FFT-based beamforming
when using relatively broadband signals is considered. The main attention is paid to the MLS
with a static beam pattern, at the same time, obtained results are also applicable to ranging
systems that provide dynamic beam control. The aim of the study is to establish the relatio nship
between the relative width of the signal spectrum and signal level in the spatial channel
of the MLS with a given maximum beam steering. A qualitative condition for the applicability
of FFT-based spatial beamforming for a probing signal with a given relative bandwidth is
determined. An analytical expression linking the signal attenuation coefficient in the spatial
channel with the following signal and receiver characteristics was obtained: the number of
elements of the linear equidistant antenna array, the distance between array elements, beam
steering, the correlation function of the complex envelope of the signal, the window function
for weighting the matched filter response in spectral domain. Presented results can be useful
in designing multibeam echo sounders, providing high resolution both in range and in angular
coordinates.

Designing nonlinear control systems is still difficult so many researchers are trying to find
some useful ways and methods to solve this problem. As a result of such research, some methods
have been seen trying to design a good enough control system for nonlinear plants. But a disadvantage
of these methods is the complexity, so it created a need to compare some methods to determine
which one is the easiest method to design a control system for nonlinear plants. It was
found a way to compare two methods, which is comparing the regions of initial conditions of the
systems which are designed using these methods. Two analytical nonlinear control systems design
methods are compared on the example of the design control systems mobile robots. The algebraic
polynomial-matrix method uses a quasilinear model, and the feedback linearization method uses
particular feedback. Both considered methods give a bounded domain of equilibrium attraction,
therefore the obtained control systems can be operated only with bounded initial conditions.
The numerical example of designing the control systems for one object by these methods and the
estimates of the attraction areas of the system’s equilibriums of these systems are given in the
paper. As a result of this paper, it was found that using the algebraic polynomial-matrix method
will get a bigger cross section of initial conditions of the plant’s variable than the same cross section
which is given by the feedback linearization method.

The aim of the work is to evaluate the cryptographic properties of the pCollapser family of pseudo-
random functions (PRF) based on the study of the properties of its mini_pCollapser_12x12 miniversion
using fixed substitutions with extremely low cryptographic properties. As a comparison element,
we used a mini-version of a typical function based on an SP-net, containing a similar number of fixed
substitutions, and having a similar input/output dimension equal to 12 bits. To achieve this goal, the
following tasks were solved: – determination of the structure of the studied functions and the number of
rounds; – definition of a model for the formation of fixed substitutions with extremely low cryptographic
properties; – generation of sets of 6-bit fixed substitutions with extremely low cryptographic properties; – inclusion of the substitutions obtained into the functions under study and determination of the main
cryptographic properties of functions – the maximum dominance value for individual key values and the
maximum dominance value averaged over the entire set of keys, the maximum and averaged over the
entire set of keys value in the difference distribution table, algebraic degree and algebraic immunity;
– analysis of the obtained results. The paper presents two models for the formation of fixed substitutions
with extremely low cryptographic properties – based on the mixing of cell values in a pre-filled table
and based on the simplest ARX function (consisting of modulo addition, cyclic shift and XOR). The use
of fixed substitutions with extremely low non-linearity makes it possible to estimate how complex (nonlinear)
the function under study is and what minimum level of non-linearity is necessary to effectively
destroy the statistical dependencies between input/output data. In addition, it becomes clear that ARX
functions can be used as non-linear elements, which often have controversial and clearly low cryptographic
properties, but allow creating high-speed software and hardware implementations. It has been
determined that the PRF pCollapser mini-version, in contrast to the typical function based on the SP
network, makes it possible to obtain a high-quality non-linear function from the set of ARX-functions
with extremely low cryptographic properties, given that no other non-linear elements are presented in
pCollapser. The obtained results reflect the existence of a fundamental difference between the
pCollapser PRF and a typical SP-network based PRF and confirm the correctness of the concept of
PD-sbox pseudo-dynamic substitutions and the pCollapser function consisting of them as a whole.

The purpose of the work is to use a rank model of signal processing for signaling the landing
of an amphibious aircraft. Rank processing refers to nonparametric methods of detecting a
signal against a background of interference. Nonparametric methods are used if the functional
type of the input data distribution is unknown and only the most general differences between the
presence and absence of a signal are indicated. Almost all nonparametric detectors contain devices
as a component element that perform some invariant transformation of the S array of sample
values of X. As a result of this transformation, a new array Z = SX is formed, the distribution of
elements of which is precisely known in the absence of a signal. The transformation S, which is
chosen heuristically, allows us to reduce the problem of detecting a signal against a background
of interference with an unknown distribution to the problem of testing a simple hypothesis regarding
the distribution of the array Z. Research objectives: 1) preliminary digital filtering of amphibious
aircraft flight records for the use of rank processing; 2) conducting an experiment to obtain
the characteristics of a rank detector used to signal the landing of an amphibious aircraft;
3) analysis of the results obtained. A model of signal processing of a vibration sensor for signaling
the landing of an amphibious aircraft is proposed. The model consists of a bandpass filter (PF), a
COEX calculator, a divider, a rank detector and a reference sample generator. The rank detector
allows you to reduce the task of detecting the vibration sensor signal against the background of
interference to the task of testing a simple hypothesis regarding the distribution of ranks. The nonparametric
Watson agreement criterion is used to make a decision on the presence of a drive signal.
The proposed processing model provides the following parameters of the flood alarm system:
1) insensitivity to changing characteristics of signals and interference, 2) the decision-making
algorithm guarantees high quality of detection in conditions of significant a priori uncertainty.
The results of the conducted studies show: 1) the distribution of ranks in the absence of a signal is
always approximated by a uniform distribution law. In situations where a signal is present in the
mixture, the uniform distribution is destroyed, and the presence of a signal is determined by a set
threshold, 2) the sensor based on rank criteria provides high quality detection of the amphibious
aircraft landing signal. The proposed approach to solving the detection problem can find a place
in many applied problems where there is a priori uncertainty. For example, in radar, sonar, communications,
medicine and other fields of science and technology.

The problem of printed gratings application is considered as converters of electromagnetic waves
polarization and polarizing modulators. Two directions in development of antenna engineering are
considered in this paper. In each of them the scattering fields control of an antenna arrays allows essentially
to expand functionalities of radio engineering sets. The first direction is the creation of auxiliary
depolarizing reflectors for two-mirror reflector antennas and folded lenses. In addition, in meanderline
polarizers based on printed gratings, it is possible to constructively realize the necessary phase distributions of the field on their surfaces. Thus, it becomes possible to use such meanderline polarizers to create
multifunctional microwave antenna radomes. The second direction is connected to application of
antenna arrays for a reduction of a radar cross section of the radar-tracking targets. Transformation of
a field polarization by an antenna array allows to achieve both these purposes. In an aspect of high cost
and complexity of arrays experimental researches as a method of the analysis the mathematical simulation
is selected. Besides, it is shown that introduction of impedance loads in the construction of the reradiating
elements of the printed grating opens additional possibilities for controlling the field scattered
by it. Thus, meanderline polarizers with improved characteristics can be realized on the basis of
microstrip-pin gratings. The given results can be used for choosing the most of rational electrodynamic
structure geometry variant at decision of particular problems by antennas engineering. The possible flat
arrays based on printed complicated shape elements application area is also discussed and it's shown
these arrays are the very attractive type for controllable radioelectronic covers designing at microwaves.
Some numerical results presented prove the possibility of a printed arrays application as smart
covers microwave modules.

A bank of circuit design solutions for active RC filters of the second order is considered - a
low-pass filter, a high-pass filter and band-pass filters, in which independent tuning of the main
parameters - the pole frequency, the quality factor of the pole and the transmission coefficient is
provided. From these positions, the requirements for three special transfer functions of a multipole
frequency-setting RC circuit, which contains two resistors and two capacitors, are formulated.
By choosing the coefficients of the numerator of the first transfer function, the type of the required
filter (LPF, HPF, BPF) is implemented. The coefficients of the second transfer function are chosen
so that they affect only the frequency of the pole. It should be noted that, depending on the set of
coefficients of the transfer function numerator polynomial, the developed circuits have the property
of lowering the pole frequency or increasing the pole frequency. In this case, the choice of parameters
of the third transfer function provides the necessary attenuation of the pole. Using the
The introduction describes a generalized architecture of second-order active RC filters, which
allows implementing an algorithm for step-by-step tuning of the main parameters and can be used
as the basis for the synthesis of many other modifications of active RC filters. For correct independent
adjustment, the following sequence must be observed: the frequency of the pole, the second
stage is the adjustment of the quality factor of the pole, and the third stage is the scaling
factor. The stages of synthesis of this class of active RC filters are considered, the coefficients of
the transfer functions of the presented circuits of 12 band-pass filters, a high-pass filter and a lowpass
filter, confirmed by 14 patents of the Russian Federation, are given.

Around the world, wireless or distant communication has become fundamental and indispensable.
Every day, billions of users access calls, the internet, and social media. Many electrical
equipment, including the antenna, are used in the sophisticated networks and systems that support
that massive information interchange. An electrical device known as an antenna sends or receives
information across space. The antenna is a key component in many systems, including radio and
television transmission, communications receivers, radar, cellular phones, Bluetooth-enabled
gadgets, and satellite communications. The rapid expansion of wireless technology and personal
communication has increased the demand for multiband antennas, which can operate at several
frequencies and are suited for a variety of applications. Dual-band coplanar waveguide (CPW)
fed rectangular microstrip patch antenna for 5G, WiMAX band, ISM Band, and WLAN applications
is presented in this paper. The proposed antenna is robust, cheap, light weight, and easy to
fabricate, resonating at 2.4 GHz in -12.182379 s11 with 205.7 MHz BW and 3.42 GHz
in -37.344879 s11 with 464.9 MHz BW whereas gain is 3.85 and 3.41 respectively. Patch elements
are placed on isolation FR408 (loss-free) substrate of relative permittivity 3.75 kept at a substrate
height of 1.6 mm. Results of simulation are presented using CST STUDIO SUITE 2019.

The work is devoted to the problem of diagnosing automobile internal combustion engines.
The problem of controlling the condition of internal combustion engines is now the most relevant
because of the increasing number of cars and tightening of environmental requirements. The paper
considers the consequences of a faulty internal combustion engine. The aim of the work is to
develop a method that can help to detect the fault most accurately and quickly. With the advent of
modern technologies the long known method of internal combustion engines condition estimation
by the sound can become the most advanced, as the human factor is excluded, for signal processing
the computer techniques of the sound spectrum analysis which is carried out by means of
artificial neural networks are applied. The application of artificial neural networks for analyzing
the sound spectrum has found application in speech recognition and for diagnosing respiratory
diseases. In the article the mechanisms which are capable to generate sound signals during internal
combustion engine work are considered, some of them are phased i.e. are connected to working
strokes, some of them are not phased. The proposed method of diagnostics allows selecting
"useful" sounds from the total number of engine noises and, after a comparative analysis, pointing
to a node whose sound differs from the reference, serviceable one. Scientific novelty lies in the fact
that the diagnostic process becomes automated, all the sounds recorded by sensors are processed
in a computer or a special scanner, the display shows information about the condition of certain
nodes, in contrast to traditional methods where the diagnosis is carried out visually or by ear. This
increases diagnostic accuracy and reduces overall labor intensity by eliminating partial or complete
engine disassembly

The article is devoted to the topical problem of analyzing the risks that arise during the operation
of aircraft in cases where portable electronic devices are on board the aircraft, and the
choice of methods for checking the resistance of onboard equipment to the effects of such devices.
The article considers all possible ways of propagation of spurious and intentional emissions from
portable electronic devices to avionics systems and analyzes two main aspects of the impact of
portable electronic devices on aircraft avionics. The first aspect defines the aircraft system and
qualification guidelines for radio-exposed equipment that provide immunity to radio emissions
from intentionally transmitting portable electronic devices. This is usually interpreted as protection
against the impact of portable electronic devices "through the back door." The second aspect
defines acceptable interference that causes bandwidth loss between aircraft radios and spurious
portable electronic devices. This is commonly referred to as "front door" protection against portable
devices. Based on an analysis of the main risks associated with interference from portable
electronic devices to aircraft systems, aircraft systems have been identified for which a demonstration
of compliance with the resistance to the effects of portable electronic devices must be performed.
In order to demonstrate the suitability of the front door immunity of aircraft equipment, it
is necessary to assess the levels of possible interference from portable electronic devices in the
reception band of aircraft equipment. Demonstrating the compliance of aircraft equipment for
“through the back door” exposure is similar to demonstrating resistance to high-intensity electromagnetic
fields and indirect lightning strikes. It is necessary to perform one of the two proposed
methods to establish their susceptibility to radio emission and control levels of the susceptibility of
aircraft systems to radio emission. The first method is related to the delivery of equipment to the
test bench for RF emissions, the second method is to test the systems that are installed on the applicable
aircraft. Recommendations have been developed on the choice of methods for verifying
the resistance of aircraft systems to the impact of portable devices. The impact aspects analyzed
will help determine the scope and methodology for conducting tests to remove restrictions on the
use of portable electronic devices on board aircraft.

An experimental study of a balanced mixer based on 2A116A-1 diodes was carried out.
Conversion losses were measured in the input frequency range of 2450 ± 45 MHz during down
conversion to an intermediate frequency of 2125 MHz. Conversion loss does not exceed 20 dB in a
narrow band of 2440±10 MHz. The amplitude characteristic of the mixer was taken, from which it
can be seen that it is linear for input signals up to 0 dBm (1 mW). The dependence of conversion
losses on the local oscillator power is studied. It is shown that the minimum losses are observed at
a local oscillator power of 13 dBm (20 mW). The combination frequency spectrum at the mixer
output does not contain parasitic conversion products above minus 50 dB with respect to the useful
signal in the 100 MHz bandwidth. The mixer is recommended for use in receiving and transmitting
equipment and measuring equipment. Comparison with other mixers shows a noticeable advantage
- high selectivity in relation to out-of-band signals. This is achieved by applying two band
pass filters and a low pass filter. Three filters were simulated in the Microwave Office software
package. Models and amplitude-frequency characteristics of three filters from Microwave Office
are given. The mixer is made in a frame-type case made of aluminum. It has two ceramic boards
sized 24x30 mm (material 22xc). The method of manufacturing a printed circuit board pattern is
thin-film technology. The case is closed by two tight covers. All three connectors are type
IX GOST13317, socket.