DOI: 10.26102/2310-6018/2022.37.2.004
In the article, errors that occur when using the most common current sources with low output resistance (voltage amplifiers), feeding coils of biological object modification sets by means of a magnetic field are identified with the aid of the proposed modeling methods. To exemplify the operability of the models under consideration, oscillograms of changes in the magnetic field induction time in the coil of the set, when it is powered by a voltage amplifier having a low output resistance, are given. As an alternative, it is suggested to employ a developed and assembled specialized current source with a high output resistance, voltage-controlled (ITUN), designed to work with an inductive load. The magnetic field, generated by the coil of the set, fully corresponds to the current, flowing through it from the current source. The article describes the layout of such current source, as well as a high-speed system for limiting the input signal, which enables the protection of the circuit power elements from overloads that occur when working on an inductive load. As an illustration of the effectiveness of the magnetic field creation method, the oscillograms of the change from the induction time of the magnetic field produced in the coil of the set, when it is powered from the current source layout, are presented. In order to implement the layout of the magnetic set and monitor the state of the magnetic field being measured, a high-speed magnetometer was additionally designed and built, which allows reading data in real time.
Keywords: magnetic set, ITUN, magnetometer, magnetic field, modification of biological objects
DOI: 10.26102/2310-6018/2022.36.1.011
The article discusses and substantiates the principle of multi-range images combining and processing based on matrix devices with charge coupling. The developed principle is proposed as an alternative to the software implementation of the task of multi-range images combining and processing. The analysis of existing methods of combining multi-range images is carried out and the insufficiency of these methods in terms of increasing the resulting image information content is confirmed. The method for images combining and processing with a view to enhancing the information content, which is performed by means of digital methods, is considered. The possibility and prospects of the specified problem employment with the aid of discrete-analog systems, namely, the basis of matrix devices with charge coupled, have been affirmed. The principle of a two-stage impact on charge packets, which form image pixels in matrix devices with charge-coupled devices, is suggested with the aim of dividing them in specified proportions, indicated in the digital method, and introducing the necessary division parts into adjacent storage cells. The application simplicity of the procedure for dividing and moving parts of the charge packets by changing the voltages on the phase buses of the matrix device with charge coupling is shown. The transfer characteristic of the charge coupled matrix device in the outlined mode is determined analytically. The coefficient of the transfer characteristic squareness is ascertained.
Keywords: charge coupled matrix device, images, processing, charge packets, charge pack division
DOI: 10.26102/2310-6018/2022.36.1.010
In this article, suggestions are given for modeling the processes of cell separation by the magnitude of magnetic susceptibility. On the basis of the proposed model, an operating separation unit was created, and its description was given. To improve the efficiency of the operating separation unit, in comparison with existing equivalents, design solutions were introduced. It has been experimentally established that a lattice, consisting of rods of soft magnetic steel, which is a spatially periodic polygradient structure, can secrete cells of various magnetic susceptibility when the magnitude of the external magnetic field, applied to this structure, and the constant flow rate of the working medium, pumped through it, change. Additionally, we have also developed a technique for isolating cells with different magnetic susceptibility by means of the operating unit. The derived method makes it possible to acquire "spectra" of the magnetic susceptibility of cell samples. After the calibration of the unit, it is possible to predict the expected results of the cell separation analysis. The efficiency of the devised separator rises with an increase in the number of rows (rods) in the periodic structure. The accuracy of the findings depends on the pumping time. With weak fields, the shutter speed needs to be accelerated. Non-magnetic or weakly magnetic biological cells may remain in the swirl zones. This phenomenon negatively affects the quality of the samples obtained, especially with weak magnetic fields.
Keywords: separator, magnetic field, biocells, magnetic susceptibility, high-gradient magnetic separation, method of biocell separation
DOI: 10.26102/2310-6018/2022.36.1.009
The article completes a series of three original publications, related to the modeling of seismic risks in the geological environment in design and construction of critical infrastructure facilities. The preparation of the series is aimed at achieving the goal of finding a quantitative correspondence of seismic risks, calculated according to mathematical models, with seismic impacts, regulated in the Seismic building design code (SP 14.13330.2018). For this purpose, the tasks are solved: in the first article the criteria for choosing test territories are justified, and the territory of Armenia and neighboring states is selected as a test region; in the second - by the example of the test area, an assessment of the probabilistic seismic risk was performed with the help of specially created mathematical models at the regional and local scale levels; in the third - mathematical models and software were developed to determine the compliance of the calculated seismic effects, regulated by the design code with the values of the probabilistic seismic risk, obtained using mathematical modeling. The final article concludes that the prospects for further research are associated with the construction of a new seismic intensity scale of possible earthquakes as a function of the calculated probabilistic seismic risk and the depth of the possible earthquake source, as well as the creation of a special normalization scale that enables to transfer the probabilistic seismic risk, calculated for any region, into intensity as a measure of shaking in points of a single macro seismic scale. The construction of similar scales is highly relevant for the calculated kinematic parameters, currently employed in the design code – peak acceleration, displacement velocity and the actual displacement of the ground.
Keywords: modeling, seismic risk, geological environment, test area, building codes and regulations
DOI: 10.26102/2310-6018/2022.36.1.008
The article presents the description and results of the implementation of regional and local mathematical models, created to address the problem of estimating stresses, deformations and displacements in the geological environment. In the regional model, the main factors, causing the occurrence of stresses, displacements and deformations of the geological environment, are the inhomogeneities of the anomalous gravitational field distribution in isostatic reduction and the features of the Moho surface relief. To describe a local deterministic model, which is employed to estimate the stress-strain state of a three-dimensional elastic space, the displacement equations, solved by the Galerkin method, are utilized. Computer versions of models, provided with digital information, open up fundamentally new opportunities for the construction sector in carrying out the tasks of assessment, analysis and forecasting of the geological environment seismic characteristics. Mathematical models and calculations, obtained with their application, are a reliable basis in the field of design and construction of buildings and structures under difficult geological conditions. Survey work and the construction itself require significant material, technical and financial resources. It is concluded that the use of modern digital technologies for assessing, analyzing and predicting seismic risks reduces unjustified losses and develops the intellectual component of the methods exploited as well as methods of design surveys.
Keywords: construction, computer modeling, geological environment, stress-dynamic state, seismic risk
DOI: 10.26102/2310-6018/2022.36.1.007
The article considers the model for solving the problem of seismic risk quantitative correlation, calculated on the basis of modeling, with seismic impacts regulated in the Seismic building design code. The paper is the first part in a series of scientific publications on the subject. For the first time, it substantiates the criteria for selecting test territories, describes the methodology for verifying the adequacy of seismic risk assessment models, characterizes a probabilistic model of energy transitions in a stress-strain geological environment, and presents an approach to evaluating model parameters through the potential energy transformation indicators of the stress-strain geological environment. The content of the other two parts of the series is indicated. Armenia and neighboring states meet the criteria for choosing a region for practical testing of the model: high seismicity, the necessary information base and proven adequacy of the seismic risk model application at all deep levels of the earthquake epicenter locations. The method of the adequacy verification of the seismic risk assessment mathematical model, using the Student's criterion, is examined in detail. It is shown that when estimating the parameters of transitions between states of the model, described by the Kolmogorov equations, it is important to take into account both the influence of regional fields (anomalous gravitational field) and local fields (modern tectonic movements). Thus, a rationale is provided for employing two deterministic models – regional and local - for practical evaluation of stresses and displacements in the geological environment.
Keywords: model, seismic risk, stress-deformed geological environment, test territory, criterion, regional and local geophysical fields
DOI: 10.26102/2310-6018/2022.36.1.016
The task of detecting and observing targets has always been relevant. One of the most important objectives of radar development is to improve target recognition. There are two ways to achieve this – firstly, the installation of more powerful radar systems, which is very expensive and hard to implement under the conditions of limited space, for example, on airplanes; secondly, the quality of the received signal can be enhanced with the aid of mathematical methods, which allows to considerably save on setting up additional equipment. One of the main problems of recognition is the fact that the number and angular location of targets can be difficult to determine from the signal received by the radar system. This problem can be addressed by employing a wavelet transform. This method enables to overcome the Rayleigh criterion, that makes it possible to obtain an angular super-resolution (to surmount the classical diffraction limit of the spatial resolution of an image focused by a lens that is less than half the radiation wavelength). The article uses a mathematical model of a radar station to present the results of numerical experiments to achieve super-resolution by means of algebraic methods at a significant noise level. We examine the suitability of utilizing different types of wavelets, namely the Haar wavelet, the symmetric Haar wavelet, and the Wave wavelet.
Keywords: wavelet transform, computer modeling, super-resolution, target search, simulation model
DOI: 10.26102/2310-6018/2022.36.1.006
The employment of machine learning systems is an effective way to achieve goals, operating with large amounts of data, which contributes to their widespread implementation in various fields of activity. At the same time, such systems are currently vulnerable to malicious manipulations that can lead to a violation of integrity and confidentiality, which is confirmed by the fact that these threats were included in the Information Security Threats Databank by the Federal Service for Technical and Expert Control (FSTEC) in December 2020. Under these conditions, ensuring the safe use of machine learning systems at all stages of the life cycle is an important task. This explains the relevance of the study. The paper discusses the existing security methods, proposed by various researchers and described in the scientific literature, their shortcomings, and prospects for further application. In this respect, this review article aims to identify research issues, relating to machine learning system security, with a view to subsequent development of technical and scientific solutions, regarding the matter. The materials of the article are of practical value for information security specialists and developers of machine learning systems.
Keywords: machine learning, malicious impact, integrity, confidentiality, security