The synthesis of a composite material based on graphitic carbon nitride by pyrolytic decomposition at 550 °C of a mechanical mixture of thiourea with the addition of aluminum powder in the amount of 5–30 wt.% has been studied. According to the scanning results by means of electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractometry the synthesized material consists of carbon nitride, aluminum sulfide, residual metallic aluminum and aluminum hydroxide. The excess of metallic aluminum is due to the partial interaction with sulfur-containing volatile substances formed during the thermal decomposition of thiourea. It is shown that the intensity and width of the photoluminescence spectra of the synthesized composites are determined by the aluminum concentration in the initial mixture. As the aluminum concentration increases from 5 to 30 wt.%, the photoluminescence intensity maximum shifts to the long wavelength region from 534 to 560 nm. This can be used to create optoelectronic devices based on the graphitic carbon nitride.

Passivation of the film conductive system of integrated circuits makes it more reliable by increasing the resistance to electromigration. The problem of manufacturing a passivating layer on the formed current-conducting system of an integrated circuit, obtained in a single technological cycle, including isotropic plasma-chemical etching of an aluminum alloy layer to a depth of 8–12 nm and isotropic plasma-chemical nitriding of the surface of the obtained current-carrying tracks until the aluminum nitride thickness from 10 to 50 nm, is considered. This task makes it possible to form a dielectric film based on silicon dioxide on a silicon substrate with active regions, etch contact windows to active elements of the substrate in the dielectric film, deposit a barrier layer 0.005–0.050 µm thick, and deposit an aluminum alloy film 0.5–2.0 um and much more.

The article proposes a model for predicting the content of metal components of complex oxide films deposited by reactive magnetron sputtering of a two-component composite target in Ar/O₂ gas mixture. The model takes into account the sputtering yield and ion-electron emission coefficients of the sputtered metals and their oxides, the distribution of the ion current density on the target, and the rate of the chemical reaction of the formation of oxides of these metals. To verify the proposed model, studies of the elemental composition of titanium-aluminum oxide films deposited by magnetron sputtering of a Ti-Al composite target in Ar and Ar/O₂ gas mixture were carried out. It has been established that the model adequately describes the change in the content of metals in the deposited films with a change in the oxygen flow into the chamber. The simulation error does not exceed 10 %, this makes it possible to use the proposed model for predicting the content of metals in a film during reactive sputtering of two-component composite targets.

To study the S-parameters and dielectric permittivity of polycor and GaAs samples, a vector network analyzer R4-MWM-118 with a special measuring cell and a modified Nicholson–Ross–Weir method were used. The use of polynomial Chebyshev criteria in R4-MWM-118 for approximation in digital filtering made it possible to reduce the distortion of the achieved approximations of S-parameters. The use of digital filtering made it possible to eliminate the subjective error of the operator in the analysis and measurements with the presence of a “noise” component, to improve qualitatively the perception of the amplitude-frequency characteristic and to exclude uninformative changes in the instrument readings at any point in the frequency range. The dependences of the amplitudes and phases of the transmission and reflection coefficients, as well as the dielectric permittivity of the samples under study on the frequency in the range 78.33–118.10 GHz are obtained.

The development of technologies leads to the need of revising the methods used to obtain cryptographic keys. The randomness parameters of sequences generated by physical random sequence generators are affected by the physical parameters of the recording equipment and the environment. The requirements for the randomness of the sequence, when passing the binary test, are obtained. It is shown that as the sequence length increases, the requirements for possible deviations from the equiprobable distribution of 0 and 1 increase. The randomness stability of the sequences generated by the generator based on the study of photons is estimated. The oscillator under study consists of an LED and a compact silicon photomultiplier designed to detect low-power light radiation. Possible physical processes leading to the deterioration of the randomness of sequences are shown. The possibility of using a generator of random numerical sequences based on a small-sized silicon photomultiplier for cryptographic purposes is estimated.

One of the main problems in the use of the radio frequency spectrum is its scarcity. This is due not only to its natural properties as a resource, but also to the inefficiency of its use. Work in this direction was carried out by scientists. In order to release the inefficiently used part of the radio frequency spectrum, it is necessary to develop management measures and mechanisms that create the most unfavorable conditions for the operation of this part of the spectrum by operators. The article discusses proposals for the implementation of the methodology, the model and criteria for a symbolic description of the assessment of the effectiveness of the use of the radio frequency spectrum, including information and software implementation of a multi-agent system that allows for automated decision making, for a comprehensive assessment of the effectiveness of the use of the radio frequency spectrum. A model of the overall efficiency of using the radio frequency spectrum based on three types of efficiency has been proposed, and a scale of intervals for these types has been developed. An assessment of the efficiency of the radio frequency spectrum based on a reference network of cellular mobile communications has been performed. A decision making variant based on the results of evaluating this efficiency is presented.

In recent years, research has been actively carried out aimed at developing the concept of construction and ways of technical implementation of ground penetrating radars with continuous wave linear-frequency-modulated (LFM) radiation. The key prerequisites for the creation of such systems are the complex consideration of the operating conditions of the radio channel in the near field, including the features associated with multichannel leakage of the probing signal components into the reception path, the presence of multipath reflections from the covering surface, the variable speed of the electromagnetic wave, and the provision of linear processing of a continuous group broadband radio signal with large dynamic range. The paper proposes and describes a scheme of a laboratory stand for LFM GPR research and optimization of the energy characteristics in modes with critical levels of reflections. The results of experiments on the analysis and optimization of the parameters of the end-to-end transfer characteristic of the radio channel are presented. Response studies were performed for two types of antennas at different suspension heights. The responses of the system to an increase in the durtion of the probing pulse and a change in the type of window function were evaluated. An empirical dependence of signal losses during propagation in radio channels of LFM GPR has been established. The conducted studies will improve the energy characteristics of ground penetrating radars with continuous LFM radiation by increasing the detection efficiency of shallow and near-surface objects.

The features of building on the basis of programmable logic integrated circuits of “arbiter” physical unclonable functions (APUF) are considered. The problem of asymmetry of pairs of APUF paths is indicated and the negative impact of this phenomenon on their characteristics is noted. A time measuring system based on a ring oscillator scheme, which is used to analyze the time characteristics of APUF paths, is described. A method for automatic balancing of signal propagation delays through the APUF paths based on the calculation of the corrective value is proposed. The consistency of the proposed balancing technique is experimentally confirmed based on the improvement in the characteristics of the APUF after its implementation. A digital scheme of this technique is presented, which can form the basis for the development of a delay auto correction scheme through APUF paths with different levels of autonomy.

The article presents theoretical calculations that explain the origin of errors in the course of an aircraft in an automated control system when pointing at a maneuvering air target. The peculiarity of pointing at a maneuvering target is related to the execution of turns, which are characterized by overloads. The curvature of the trajectory in such areas is usually approximated by a circle of a certain radius, depending on the value of the overload and flight speed to intercept. In the automated control system, the current course of the aircraft is determined as the direction of movement by two marks corresponding to the current and previous moments of information update time. For a target moving in a straight line, this approach is valid. However, in a turn where the guidance path is a curved line, the true heading will correspond to the tangent at the turn point. The difference in these approaches determines the error of the course calculation. This article provides a formulaic calculation of turn radii for flight speeds to intercept an air target and overloads, as well as the calculation of true and current courses. The peculiarity of the methodology is a strict formalized mathematical description. The article presents the dependences of heading errors from the aircraft’s intercept flight speed and overloads using the example of the Su-27 multifunctional fighter.

The aim of the study is to develop a mathematical model for the synthesis of technological operations in the structure of algorithms for a system of automated design of technological processes. When solving the problem of synthesis of technological operations in the structure of algorithms of the automated design system of technological processes for manufacturing prototypes of structurally complex products, the following algorithms are used: solving the direct choice problem; formation of a set of possible alternatives; checking possible alternatives for admissibility; formation of a set of acceptable alternatives; determining the set of desired typical technological solutions and optimizing the choice of solutions. A block diagram of the system of algorithms for the process of synthesis of technological operations, based on a combination of individual and standard technological solutions in the design of technological processes for the experimental production of prototypes of structurally complex products, has been obtained.

The problem of assessing the quality of combining component images formed in two synchronous channels of an atomic force microscope (AFM images), is considered. A computationally simple quality metric for combining component AFM images, based on local correlation coefficients is proposed, taking into account the contribution of each of the component AFM images to the resulting combined AFM image and the correlation between component AFM images. It is shown that local correlation provides a higher accuracy of AFM images combination quality estimation in comparison to the global correlation.

To improve the person re-identification system accuracy, an integrated approach is proposed in the formation of a training sample for convolutional neural networks, which involves the use of a new image dataset, an increase in the training examples number using existing datasets, and the use of a number of transformations to increase their diversity. The created dataset PolReID1077 contains images of people that were obtained in all seasons, which will improve the correct operation of re-identification systems when the seasons change. Another PolReID1077 advantage is the video data use obtained from external and internal surveillance in a large number of different filming locations. Therefore, the people images in the created set are characterized by the variability of the background, brightness and color characteristics. Joining the created dataset with the existing CUHK02, CUHK03, Market-1501, DukeMTMC-ReID and MSMT17 sets made it possible to obtain 109 772 images for training. An increase in the variety of generated examples is achieved by applying a cyclic shift to them, eliminating color and replacing a fragment with a reduced copy of another image. The research results on estimating the accuracy of re-identification for the ResNet-50 and DenseNet-121 convolutional neural networks during their training, using the proposed approach to form a training sample, are presented.

The results of a study of the architecture of hardware and software for unidirectional data transmission in computer networks are presented. The architecture is presented in the form of optical galvanic isolation, media converters and proxy servers, excluding bidirectional data transmission at the hardware level. Work on unidirectional data transmission is carried out on the basis of the UDP transport protocol, which provides operation without establishing bidirectional interaction. Unidirectional data transfer is carried out by a proxy server running a special sender’s software that performs unidirectional data file transfer. This software converts the source data file into a unidirectional stream of UDP datagrams. To receive a unidirectional stream of UDP datagrams, a proxy server is used, on which the recipient’s special software is running. The receiving proxy server receives, processes and generates the source data file. The reliability of the unidirectional transmission of data files is ensured by redundancy (multiple transmission) and checksum verification.

The results of studying the parameters of the spectra of speech signals by machine learning with the use of neural networks are presented. This study was carried out in order to confirm experimentally the possibility of performing an assessment of these parameters for the detection of Parkinson’s disease in the early stages (IT diagnostics). During the study, the public database was used, which systematized the spectra of vowel sounds uttered by patients with Parkinson’s disease. The applied method is binary data classification. In the course of the study, the speech data spectrum was first preprocessed, which consisted of filtering it in order to remove its noise components and eliminate bursts and gaps in it. Then the parameters of the processed spectrum of speech data were determined: average value, maximum and minimum, peak, wavelet coefficients, MFCC and TQWT. After that, the object was selected using the PCA algorithm. The model was trained using the Knn and Random Forest algorithms, as well as the Bayesian neural network. The Bayesian optimization algorithm and the GridSearch method were used to find the best model hyperparameters. It has been established that when using Knn, Random Forest and Bayesian neural network, it is possible to increase the accuracy of recognition of Parkinson’s disease by 94.7; 88.16 and 74.74 %, respectively. A similar study by other scientists showed that the recognition accuracy of data sets was only 86 %.

The article gives a classification of metrics of specialized Riemannian spaces, which carry four algebras at once in metrics D_m1 – real numbers, C_m2 – complex numbers, H_m3 – quaternions, O_m4 – octions. Dimension of spaces n=m₁+2m₂+4m₃+8m₄ .The article presents a picture of lacunar spaces V_n^4a also a classification of metrics by groups of isometric G_r and homothetic P_r movements (r is the dimension of the group) is given. There are gaps in the orders r of these groups, which are called lacunae. Here are two lacunae and metrics of spaces V_n^4a of the first three lacunarities in the image of I. P. Egorov. It is established that among the orders of r-groups of isometries G_r and homoteties P_r in specialized Riemann spaces V_n^4a of the third lacunarity, there is one order r_3max – 1, which is not feasible e. g. a punctate lacunarity was found.