This paper reports on the gas sensitivity of SnO₂(Ag) layers, consequently formed by magnetron sputtering of Sn + Ag target, oxidation of Sn_0.65Ag_0.35 layers at the temperature of 650 °С within 30 min and modified by laser radiation pulses at energy density of W = 1.5–3.2 J/cm². Using transmission electron microscopy and transmission electron diffraction it was found, that Sn_0.65Ag_0.35 and SnO₂(Ag) layers are nanocomposite with average grain size of 100–150 nm. Sn_0.65Ag_0.35 and SnO₂(Ag) layers contain grains of the following phase composition: a tetragonal β-Sn with an orthorhombic Ag₃Sn (Sn_0.65Ag_0.35, magnetron sputtering) and a tetragonal SnO₂ (cassiterite) with a face-centered cubic Ag structure (SnO₂(Ag), thermal oxidation). The sensitivity of SnO₂(Ag) layers with respect to 2000–20 000 ppm methane in the air was obtained from sensitivity S measurements at T = 200–360 °C. It is shown that pulsed laser annealing of SnO₂(Ag) layers results in up to 12 % increase of sensitivity of SnO₂(Ag) layers to methane in comparison with the initial SnO₂(Ag) layers. 

Electric properties of film structures consisting of two-dimensional layers, composed by nanocrystalline grains of a semiconductor are proposed to be modeled with an equivalent scheme, in which resistors indicate electrical resistance of current channels in metallic contacts, grain material, potential barriers between grains and layers. Numerical simulation within the model has shown that there is a nonuniform current distribution over the area of the contacts. Current density at their edges can be 3–6 times higher than in the center. Local currents and their distribution in the film bulk are determined by the grain structure of the film, number of the layers, electronic properties of the barriers between grains and layers. 

Graphene is currently considered as one of the most promising materials for the creation of new semiconductor devices for various frequency ranges. The influence of an external electric field on the properties of the band diagram of the graphene material, which is a modification of graphene using hydrogen atoms, was studied by simulating from the first principles (ab initio method). It was found that an external electric field applied to the graphene structure leads to a substantial change in its band diagrams, which is associated with a change in their type. At small values of external electric field strength, approximately up to 0.3 a.u. (1 a.u. ≈ 51.4 1010 V/m), we observe graphane zone diagrams with straight minimal gap for Г valley between conduction and valence zones. With further increase in external electric field strength the zone diagrams show indirect minimal gap. With even higher values of external electric field strength, which exceed 0.8 a.u., graphane band diagrams take on a form peculiar to metallic structures. These dependences and the resulting graphene parameters could be the basis for new heterostructure devices containing layers of graphene and other semiconductor materials. 

The article studies space-time dispersion of waves describing the behavior of quantum particles in media with eigenfrequencies f₀. The phase and group velocities of the particles are determined. The transformation of the shape of a particle from wave to corpuscular and the effect of the observer caused by this transformation are described. The instantaneous transfer of phase states of particles in the observed teleportation and involution phenomena of quantum particles states is explained. The discrepancy, observed in gravitational waves, velocities is explained. 

The paper presents a technique for estimating the information parameters of the quantization noise generated by the analog-to-digital conversion of the measuring signal. An experiment and algorithm descriptions are presented to confirm the correctness of the method for processing and extracting the information parameters of the signal and quantization noise, in which a connecting cable is used instead of a measuring antenna. The measurement results are shown in the form of graphs of the dependences of the quantization noise extraction time by accumulation on influencing factors and controlled parameters, which demonstrate the limiting values of the extraction of information parameters of the quantization noise of the analog-to-digital conversion of the measuring signal. Confirmation of the hypothesis of estimating the information parameters of the quantization noise is obtained. 

When suppressing active noise interference, an important task is to determine the mutual correlation function and the power of noise signals at the outputs of receiving channels. The solution of this problem makes it possible to analyze the influence of non-identical frequency characteristics of receiving channels on the quality of compensation of active noise interference. The analysis was carried out for a model of the frequency characteristics of the receiving channels in the form of the frequency response of a single resonant circuit in a narrow-band approximation. It was assumed that the frequency response of one of the channels differs from the second channel by the central frequency and bandwidth. In the analysis, an approximate approximation of the frequency response of the detuned channel was used, assuming a slight detuning of the parameters of the resonant circuit. The input noise of the receiving channels was assumed to be white. The use of the obtained results is demonstrated in obtaining an expression for the potential effectiveness of a single-channel autocompensator. 

Known results of studies of the radio frequency electromagnetic background generated in buildings by electromagnetic radiation from the peripheral equipment of 4G/5G mobile communications, including equipment for massive machine-type communication/Internet of things (mMTC/IoT) and user’s devices for wireless telephony and data transmission, are based on the use of a model of uniform random distribution of this equipment over the building internal space. The adequacy of this model for the analysis of a number of 4G/5G scenarios is questioned due to the fact that, excluding user’s devices, the main part of the mMTC/IoT peripheral radio equipment located in buildings is distributed along the walls of the premises with a tendency to concentrate them near the intersections of flat surfaces of walls, floors and ceilings. Paper presents the results of comparative estimates of the average intensity of electromagnetic background inside building for different types of distribution of the set of point sources of RF electromagnetic fields over the building interior space: for their uniform distribution over internal space and for two types of heterogeneity of this distribution: for uniform distribution of sources over building internal surfaces and with their uniform distribution along the lines of intersection of these surfaces. Results of this analysis indicate a relatively small effect of the considered types of heterogeneity in the spatial distribution of radiation sources on the estimates of the electromagnetic background average intensity created by these sources inside the building, when using a technique based on the representation of the internal space of a building as a set of solid angles, which internal space separate sections are characterized by the constancy of the sources average space density and by the average conditions for radio waves propagation in the direction of the observation point. 

The statement of the problem of the dual control of the regression object with multidimensional-matrix input and output variables and dynamic programming functional equations for its solution are given. The problem of the dual stabilization of the regression object at the given level is considered. The purpose of control is reaching the given value of the output variable by sequential control actions in production operation mode. In order to solve the problem, the regression function of the object is supposed to be affine in input variables, and the inner noise is supposed to be Gaussian. The sequential solution of the functional dynamic programming equations is performed. As a result, the optimal control action at the last control step is obtained. It is shown also that the obtaining of the optimal control actions at the other control steps is connected with big difficulties and impossible both analytically and numerically. The control action obtained at the last control step is proposed to be used at the arbitrary control step. This control action is called the control action with passive information accumulation. The dual control algorithm with passive information accumulation was programmed for numerical calculations and tested for a number of objects. It showed acceptable results for the practice. The advantages of the developed algorithm are theoretical and algorithmical generality. 

The article considers the hardware and software complex developed by the authors for the study of the joint use of technical means built on various physical principles. This hardware and software complex is a set of jointly functioning security equipment (optoelectronic system, seismic sensors, fiber-optic sensors) that solve the problem of automatic detection of moving objects in a given area of space. The hardware and software complex is based on the technical observation post developed by the authors, which provides solutions to the problems of automatic detection of moving objects in the field of view of the system sensors, as well as joint functioning with other technical means of protection. Its features and capabilities are described. The results of evaluating the effectiveness of the implementation of the developed hardware and software complex in the integrated security system are presented, using the example of one of the state border protection units. The effect is to reduce the probability of an error when making a decision about the presence of a “real” violator, as well as to increase the probability of their detection. The results of field tests of the hardware and software complex in real operating conditions on the state border section are presented. 

Uncooled bolometric type thermal detectors, combined into a matrix and placed into a focal plane array have the following characteristics: low cost, operation at room temperature, compatibility with the silicon CMOS technology, and high detecting performance; therefore recently it became a hot spot in infrared or terahertz detection field. The performance of uncooled infrared focal plane detector arrays depends on the optimization of critical parameters which are determined by geometrical design and the electrical, optical, and thermal physical properties of the detector materials. We report the study of a fabrication process and characterization of two (2D) dimensional arrays of uncooled microbolometers based on silicon (α-Si) thermo-sensing films. Because these arrays substantially reduce sensor size, they are becoming the preferred format for most modern applications. 

The problem of application of the dissimilarity measures for binary test sequences is investigated. Their relevance in generating controlled random tests is substantiated. Dissimilarity measure AD(T_i, T_k) between test sets T_i and T_k is considered, using the characteristic of the distance D(t_i,j, t_k,r) between t_i,j and t_k,r, which is based on the determination of independent pairs of identical data t_i,j = t_k,r belonging to two patterns T_i and T_k. This measure AD(T_i, T_k) allows us to estimate the degree of difference between two test sets T_i and T_k, which may be indistinguishable when using other difference measures, including the Hamming distance. Upper and lower estimates for the measurement of dissimilarity are obtained for the case of inverse test patterns and arbitrary test patterns T_i and T_k with different combinations of their weights w_i and w_k. Examples of calculating the boundary values of the specified dissimilarity measure and the ratio of their values are given. Experimental results confirm the correctness of the obtained boundary values of the indicated dissimilarity measure AD(T_i, T_k) and show the possibility of their application for its evaluation.

The article investigates the problem of information security of critical information infrastructures. The features of critical objects from the point of view of collecting, processing, storing and transmitting information are analysed. The set of functions performed by the information security system in critical infrastructures and the dependencies between these functions are studied. A model of the security system is proposed and the require ments for this model are defined. At the same time, the set of relations between objects and threats is represented in the form of an object-threat relationship graph, in which an edge connecting the j-th object with the i-th threat exists only when the i-th threat can directly affect the j-th object. To protect objects of critical information infrastructures from possible threats, a set of necessary methods and tools has been introduced into the model of the security system, which converts a two-sided graph into a three-sided one, such as “object – method – threat”. Further in the article, the problem of determining the optimal structure of the security system for critical information infrastructure objects is considered. It is assumed here that each threat can affect several objects, and that any object can be affected by more than one threat. The solution of this problem makes it possible to minimize the material costs to implement the methods and tools for protection and minimize damage from a security breach. 

Ecological disasters, wars in regions with microbiological weapons depots, deforestation, domestication of wild animals, consumption of infected animals, contamination of water and food products and their components, experiments with viruses, deficiencies and other defects of the immune system in modern humans and other mammals became the impetus for the evolution of new dangerous and extremely dangerous viruses. Due to the emergence of new dangerous viruses, the importance and demand for knowledge and skills of computational biology, epidemiology and virology in modern society have increased. Modern sequencers are capable of producing large amounts of bioinformatic data that is represented in the form of genomic texts. Comparative сomputational analysis of this information is necessary to clarify the issues of phylogenesis, mutational profiling, molecular evolution, identification of insertions of other genomes, annotation of genome regions, search for targets for vaccine development and pharmacotherapy. In this сontext, authors conducted a computational experiment of comparative analysis of the genomic texts of Belarusian coronavirus samples against a number of selected complete genomes of dangerous and extremely dangerous viruses and coronaviruses of various origins. Data analysis was performed using the YASS, genomic texts were downloaded from the GISAID, the custom genomic data processing pipeline based on the Galaxy bioinformatics platform was also applied. The article presents the results of an analysis of the available scientific literature and the computational experiment comparing the genomic texts of Belarusian coronavirus samples with a number of selected complete genomes of dangerous and especially dangerous viruses and coronaviruses of various origin. A significant similarity of the new coronavirus with the recombinant coronavirus, as well as partial similarity with synthetic coronavirus, Rubella, Ebola 1976, HIV-2 (human immunodeficiency virus), Middle East respiratory syndrome, simian immunodeficiency and Marburg fever viruses have been found. 

The article presents an approach, methodology, the software system based on a machine learning technologies for convolutional neural network and its use for voice (cough) recognition. Tasks of article are receiving evaluating a voice detection system with deep learning, the use of a convolutional neural network and Python language for patients with cough. The convolutional neural network has been developed, trained and tested using various datasets and Python libraries. Unlike the existing modern works related to this area, proposed system was evaluated using a real set of environmental sound data, and not only on filtered or separated voice audio tracks. The final compiled model showed a relatively high average accuracy of 85.37 %. Thus, the system is able to detect the sound of a voice in a crowded public place, and there is no need for a sound separation phase for pre-processing, as other modern systems require. Several volunteers recorded their voice sounds using microphones of their smartphones, and it was guaranteed that they would test their voices in public places to make noise, in addition to some audio files that were uploaded online. The results showed an average recognition accuracy – of 85.37 %, a minimum accuracy – of 78.8 % and a record – of 91.9 %.