http://rt.nure.ua/issue/feed Radiotekhnika 2024-12-24T00:58:38+02:00 Sergiy Sheiko sergiy.sheiko@nure.ua Open Journal Systems <p style="text-align: justify;">All-Ukrainian Interdepartmental Scientific and Technical Journal «<strong>Radiotekhnika</strong>» was founded and has been published since 1965. Founder – Kharkov Institute of Mining Machinery, Automation and Computer Engineering, now Kharkiv National University of Radio Electronics (NURE).</p> <p style="text-align: justify;"><a href="http://rt.nure.ua/libraryFiles/downloadPublic/2096">The Journal Radiotekhnika is Registered in the Register of Subjects in the Media Sphere of Ukraine</a>.<br />The collection is included in the List of scientific professional publications of Ukraine, category «Б», technical and physical-mathematical sciences (approved by orders of the Ministry of Education and Science: from 17.03.2020 № 409; from 02.07.2020 № 886; from 24.09.2020 № 1188).<br />The index in the Catalog of subscription editions of Ukraine is 08391.<br />Frequency of publication – 4 times a year.</p> <p>Specialties on which the editorial board of the Journal publishes articles:</p> <p>105 – Applied Physics and Nanomaterials<br />125 – Cybersecurity<br />163 – Biomedical Engineering<br />171 – Electronics<br />172 – <span class="HwtZe" lang="en"><span class="jCAhz ChMk0b"><span class="ryNqvb">Electronic communications</span></span></span> and Radio Engineering<br />173 – Avionics<br />174 – Automation, Computer-Integrated Technologies and Robotics<br />175 – Metrology and information-measuring technique<br />176 – Micro and Nanosystem Technology</p> <p style="text-align: justify;"><span class="VIiyi" lang="en"><span class="JLqJ4b ChMk0b" data-language-for-alternatives="en" data-language-to-translate-into="uk" data-phrase-index="0" data-number-of-phrases="1"><span class="Q4iAWc">Previously unpublished articles in English and Ukrainian are accepted for consideration.</span></span></span> All articles submitted to the editorial board are subject to external and internal (members of the editorial board) review.</p> <p style="text-align: justify;"><strong>Editorial <span id=":6v.co" class="tL8wMe EMoHub" dir="ltr" style="text-align: left;">Team</span>:</strong></p> <ul> <li><a href="https://nure.ua/en/staff/sergiy-sheiko">Sheiko S.O., PhD, Assoc. prof., NURE, Ukraine (Chief Editor)</a></li> </ul> <p>105 – Applied Physics and Nanomaterials</p> <ul> <li><a href="https://nure.ua/en/staff/anatoly-luchaninov">Luchaninov A.I., Dr. of Phys.-Math. Sciences, prof., prof., NURE, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/volodymyr-doroshenko">Doroshenko V.O., Dr. of Phys.-Math. Sciences, prof., NURE, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/oleksandr-konovalenko">Konovalenko O.O., Dr. of Phys.-Math. Sciences, prof., Academician of NASU, IRA NASU, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/serhii-tarapov">Tarapov S.I., Dr. of Phys.-Math. Sciences, prof., member-cor. NASU, IRE NASU, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/peter-tokarsky">Tokarsky P.L., Dr. of Phys.-Math. Sciences, prof., IRA NASU, Ukraine</a></li> </ul> <p>125 – Cybersecurity</p> <ul> <li><a href="https://nure.ua/en/staff/ivan-d-gorbenko">Gorbenko I.D., Dr. of Tech. Sciences, prof., KhNU V. N. Karazin, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/hennadii-khalimov">Khalimov H.Z., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> <li><a href="https://bit.nmu.org.ua/en/staff-eng/kotux/">Kotuh Ye.V., PhD, Assoc. prof., Dnipro University of Technology, Ukraine</a></li> </ul> <p>163 – Biomedical Engineering</p> <ul> <li><a href="https://nure.ua/en/staff/oleh-avrunin">Avrunin O.G., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/kateryna-muzyka">Muzyka K.M., Dr. of Tech. Sciences, Senior Researcher, NURE, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/valerii-semenets">Semenets V.V., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> </ul> <p>171 – Electronics</p> <ul> <li><a href="https://nure.ua/en/staff/vladimir-kartashov">Kartashov V.M., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/oleksiy-gueorguiovych-pashchenko">Pashchenko O.G., PhD, Assoc. prof., NURE, Ukraine</a></li> <li><a href="https://kkite.pnu.edu.ua/svyd-iryna-viktorivna/">Svyd I.V., PhD, Assoc. prof., PNU, Ukraine</a></li> </ul> <p>172 – Telecommunications and Radio Engineering</p> <ul> <li><a href="https://nure.ua/en/staff/dmytro-ageiev">Ageiev D.V., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/valeriy-bezruk">Bezruk V.M., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/dmytro-gretskih">Gretskih D.V., Dr. of Tech. Sciences, Assoc. prof., NURE, Ukraine</a></li> </ul> <p>173 – Avionics</p> <ul> <li><a href="https://library.khai.edu/authors/dergachov-kostyantin-yuryajovich">Dergachov K.Yu., PhD, Senior Researcher, Sciences, prof., NAU «KhAI», Ukraine</a></li> <li><a href="https://library.khai.edu/authors/kulyak-anatolyaj-stepanovich">Kulik A.S., Dr. of Tech. Sciences, prof., NAU «KhAI», Ukraine</a></li> </ul> <p>174 – Automation, Computer-Integrated Technologies and Robotics</p> <ul> <li><a href="https://nure.ua/en/staff/oleksandr-filipenko">Filipenko O.I., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> <li><a href="https://nure.ua/ru/staff/aleksandr-mihaylovich-tsyimbal">Tsymbal O.M., Dr. of Tech. Sciences, Assoc. prof., NURE, Ukraine</a></li> </ul> <p>175 – Metrology and information-measuring technique</p> <ul> <li><a href="https://nure.ua/en/staff/igor-zakharov">Zakharov I.P., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> <li><a href="https://nure.ua/en/staff/4131">Odarenko E.M., Dr. of Tech. Sciences, prof., NURE, Ukraine</a></li> </ul> <p>176 – Micro and Nanosystem Technology</p> <ul> <li><a href="https://nure.ua/en/staff/igor-bondarenko">Bondarenko I.M., Dr. of Phys.-Math. Sciences, prof., NURE, Ukraine</a></li> </ul> <p><span class="tlid-translation translation" lang="en"><span class="" title="">Members of the editorial board of foreign scientific institutions and educational institutions</span></span></p> <ul> <li><a href="https://www.iqo.uni-hannover.de/en/institute/staff/boris-chichkov/">Chichkov Boris, Dr. of Tech. Sciences, Professor, Gottfried Wilhelm Leibniz Universität, Hannover, Germany</a></li> <li><a href="https://www.chalmers.se/en/staff/Pages/marianna-ivashina.aspx">Ivashina Marianna, Full Professor, Senior Member IEEE, Department of Electrical Engineering, Chalmers University of Technology, Sweden</a></li> <li><a href="https://ieeexplore.ieee.org/author/37275597700">Markov Konstyantyn, Project Manager/Group Leader, Doct.-eng., Manufacturing, Electronics, RF360 Europe GmbH, Munich, Germany</a></li> <li><a href="https://www.researchgate.net/profile/Georgiy_Sevskiy">Sevskiy Georgiy, Project Manager/Group Leader, Doct.-eng., Manufacturing, Electronics, RF360 Europe GmbH, Munich, Germany</a></li> <li><a href="http://www.ime.uz.zgora.pl/InfoPracMore.aspx?idPrac=60">Titarenko Larysa, Dr. of Tech. Sciences, Professor, Institute of Metrology, Electronics and Computer Science, Zielona Góra, Poland</a></li> <li><a href="https://www.dtu.dk/english/service/phonebook/person?id=32148&amp;tab=1">Zhurbenko Vitaliy, Associate Professor, Member IEEE, Department of Electrical Engineering, Technical University of Denmark, Denmark</a></li> <li><a href="https://risweb.st-andrews.ac.uk/portal/en/persons/iryna-vorgul(eae47558-d8cd-47fb-aadf-ed8bf2681747).html">Irena Vorgul</a>, <a href="https://www.scopus.com/authid/detail.uri?authorId=10440690000">PhD, University of St Andrews, United Kingdom</a></li> <li><a href="http://ieti.pollub.pl/index.php/m-inst/m-inst-struktura?id=77">Wójcik Waldemar</a>, <a href="https://pub.pollub.pl/author/1303/">Doctor of Sciences, Full Professor, Faculty Electrical Engineering and Computer Science, Lublin University of Technology, Poland</a></li> </ul> http://rt.nure.ua/article/view/317419 Zero trust architecture: challenges and recommendations for successful implementation 2024-12-11T13:08:39+02:00 V.I. Yesin rt@nure.ua V.V. Vilihura rt@nure.ua D.Y. Uzlov rt@nure.ua <p>To protect the modern digital enterprise, a new approach is needed today to ensure secure access to your own corporate resources anytime, anywhere, and their efficient operation regardless of where they are located. The traditional perimeter-based network protection model is unable to adapt to the development of modern technologies. Therefore, enterprises have begun to rethink the traditional network security perimeter, leaning toward a new concept and architecture of protection. Such a concept is currently the security paradigm called "zero trust". The zero trust concept attracts special attention of researchers and practitioners, as it is able to meet new requirements for information security and cybersecurity. One of the factors contributing to the demand for zero trust architecture is the increased complexity and heterogeneity of modern IT systems. However, despite the popularization of this concept and the obvious security benefits from its use, there are certain difficulties in its implementation in enterprises. Deploying a zero trust architecture is quite complex from both a technical and organizational point of view. At the same time, interested representatives of enterprises are not yet fully aware of the advantages and disadvantages of the zero trust concept, which significantly hinders its application, which is still in the process of development. The main serious factors hindering the implementation of the zero trust concept are the lack of information for choosing a zero trust solution and the insufficient number of qualified specialists in this area. That is, today there is a problem associated with a certain lack of awareness about the concept and zero trust architecture (about their theoretical and practical significance) for choosing the right solution when building a security system for a corporate information system in modern conditions. This paper aims to solve this problem by summarizing existing research and the experience of various international companies that are implementing this approach in practice. The purpose of this paper is to assist IT enterprise information security professionals in the selection and application of enterprise-relevant, forward-looking zero trust architectures to increase the cybersecurity of the enterprise information system. This paper briefly discusses the conceptual zero trust architecture, its main logical components, deployment models, threats associated with zero trust architecture, and some recommendations for successful implementation of zero trust architecture in the IT enterprise.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/317420 Using zero watermarks for image authorship and multi-factor authentication 2024-12-11T13:57:20+02:00 V.O. Poddubnyi rt@nure.ua R.Y. Gvozdov rt@nure.ua O.V. Sievierinov rt@nure.ua <p>The relevance of this work lies in the revealed possibilities of using zero watermarks to confirm the authorship of digital images and the use of zero watermarks for images as a method of multifactor authentication.</p> <p>The paper proposes a modernized zero watermark algorithm for testing the capabilities of zero watermarks. The proposed multifactor authentication algorithm using zero watermarks.</p> <p>Tests have shown that null watermarks are not suitable for confirming authorship, as they cannot guarantee the distinction between similar images or between images of the same author. However, there is a prospect of using this technology in multi-factor authentication schemes, in combination with other authentication methods (such as password, biometrics, tokens).</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318790 Methods of information protection based on quantum image steganography 2024-12-23T21:09:57+02:00 O.I. Fediushyn rt@nure.ua Y.V. Holovko rt@nure.ua A.O. Smirnov rt@nure.ua V.M. Sukhoteplyi rt@nure.ua O.V. Chechui rt@nure.ua <p>The purpose of the article is to study information protection methods based on quantum image steganography. Traditional image protection techniques have limitations in terms of resilience and reliability. The use of quantum computing, particularly the NEQR model, offers significant advantages in enhancing the security and efficiency of watermarks and steganography. The article analyzes existing approaches to image representation in quantum states and demonstrates their superiority in digital image protection. A simulation of steganography using quantum algorithms is presented, showing improved information security.</p> <p>The article will be useful for information security professionals involved in data protection using modern quantum technologies.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318794 Technical channel of information leakage by side electromagnetic re-radiation of auxiliary technical means and systems 2024-12-23T21:59:57+02:00 V.I. Zabolotnyi rt@nure.ua A.M. Oleynikov rt@nure.ua D.M. Zabolotnyi rt@nure.ua A.K. Kustov rt@nure.ua <p>The design and implementation of a complex of technical information protection requires the identification and analysis of technical channels of information leakage. The work is devoted to the analysis of the channel of side electromagnetic re-radiation of auxiliary technical means and systems provided by the main technical means. The article presents approaches to the methodological support of the process of creating and applying separate quantitative models of TKVI, which are formed by the processes of the formation of side electromagnetic radiation, their impact on the random antenna of auxiliary technical means and systems, re-radiation of the field outside the controlled zone, their further composition with the radiation field of the main technical tool. Research is based on the theory of the electromagnetic field, current organizational documents in the field of technical information protection practice.</p> <p>Expedient areas of further research arising from related problems, namely the development of quantitative models, have been identified: leakage of information due to the phenomenon of electric induction of the electric component of the field on a random electric antenna; leakage of information due to the reradiation of the electric field component of the electric field antenna created by the OTZ magnetic antenna and vice versa.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318796 Detection of web attacks via HTTP requests using NLP techniques 2024-12-23T22:16:34+02:00 M.S. Kavetskiy rt@nure.ua V.I. Ruzhentsev rt@nure.ua <p>The work focuses on improving web attack detection methods through the analysis of HTTP traffic using natural language processing (NLP) techniques and transformer-based models, particularly BERT. The relevance of research in the field of web attack detection is underscored by the significant achievements of the model trained on an extended dataset containing 195,000 records. The developed model based on BERT demonstrates high efficiency in detecting web attacks due to its deep contextual understanding and modern Word Piece tokenizer, which better handles rare words. Unlike methods such as Doc2Vec, LSTM-CNN, or Isolation Forest, our model accounts for global word relationships enhancing its accuracy.</p> <p>Some previous studies have limitations; notably, some do not utilize state-of-the-art architectures, which limits their ability to achieve high model accuracy. Additionally, while using modern architectures, other studies operate with small datasets, limiting their capability to effectively detect various attack types and ensure high detection quality. In the context of these challenges, the created model was trained on an extended dataset, resulting in significantly better performance compared to leading analogs in the field of web attack detection. The high balanced accuracy of the model at 0.9998 confirms its effectiveness and reliability, making it a potentially important tool for cyber security applications.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318798 Refining security assessments of quantum-resistant asymmetric encryption standards taking into account the structure of q-ary lattices 2024-12-23T22:32:40+02:00 S.O. Kandii rt@nure.ua I.D. Gorbenko rt@nure.ua <p>The article provides a comprehensive analysis of modern quantum-resistant cryptographic standards security based on lattice theory, such as DSTU 8961:2019 ("Skelya"), CRYSTALS-Kyber, and CRYSTALS-Dilithium. These standards are becoming increasingly popular for solving various practical tasks due to their resistance to attacks that can be implemented on quantum computers. As quantum computing gradually transitions from the theoretical to the practical realm, there is an urgent need for the development and improvement of security models capable of addressing these new challenges. This article focuses on applying the cryptanalysis model developed in previous works to specific cryptographic standards based on lattices. Special attention is given to refining security estimates by considering the algebraic structure of q-ary lattices, which form the foundation of the cryptographic problems underlying these standards. It was found that when considering the algebraic structure of q-ary lattices, security estimates differ significantly from those obtained using the GSA model. In particular, for the key encapsulation mechanisms of DSTU 8961:2019 and CRYSTALS-Kyber, the difference between the estimates in these two models can range from 20 to 30 bits of security, with the refined estimates indicating that existing attacks are less effective than previously thought. It was also revealed that for NIST Level 1 security, decoding attacks show better performance compared to embedding attacks, whereas for NIST Level 5 security, the effectiveness of decoding attacks decreases significantly, falling behind embedding attacks. Thus, the results highlight the importance of accounting for the algebraic structure of lattices in obtaining more accurate security assessments. This allows for a better understanding of potential threats and the optimization of existing lattice-based cryptographic transformations.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318804 Probabilistic properties of solutions to the equation system of keystream generators with irregular motion 2024-12-23T22:57:42+02:00 A.M. Alekseychuk rt@nure.ua I.V. Samoylov rt@nure.ua <p>The traditional basis for constructing modern stream ciphers is keystream generators, which are based on linear shift registers and nonlinear complexity elements. One of the well-known methods for increasing the resistance of such generators, in particular, against algebraic and correlation attacks, is using irregularity into register’s motion process. The most popular keystream generators with irregular motion, used in stream ciphers are A5/1, Alpha1, LILI-128 and others, were thoroughly studied in the 1990s and 2000s. However, specialists’ interest remains relevant, it’s evidenced by recent publications dedicated to new attacks on the A5/1 cipher and some other stream ciphers, constructed based on keystream generators with irregular motion. On the one hand, this known methods for covering wide range of different keystream generators, but on the other hand, it reduces the accuracy and adequacy of conclusions about the resistance of specific ones.</p> <p>The main result of the article is probabilistic properties of solutions to the system of keystream generation equitation of keystream generators with irregular motion. In particular, a matrix representation for the average number of solutions to these systems of equitation has been obtained and conditions have been established under which a combinational generator with external control is irreversible by Huffman. Additionally, sufficient conditions for the exponential growth of the average number of solutions to keystream generation of this generator, depending on the length of output sequence, have been obtained, along with analytical expressions and estimates of probability distributions for sums of random vectors produced by motion control blocks of a certain class of combinational keystream generators. The obtained results can be applied to solving the problems of evaluation the resistance of keystream generators with external controlled motion and justifying the requirements for the cryptographic parameters of complexity nodes in such generators in such generators, which determine their resistance to correlation attacks.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318810 The problem of finding periodicity in quantum cryptanalysis of group cryptography algorithms 2024-12-23T23:22:52+02:00 Y. Kotukh rt@nure.ua G. Khalimov rt@nure.ua I. Dzhura rt@nure.ua <p>The article explores the fundamental role of quantum period determination algorithms, particularly in the context of cryptography. The work focuses on quantum algorithms that exploit periodicity, such as Shor's algorithm, which is central to efficient integer factorization. It highlights the challenges quantum algorithms face when applied to non-Abelian groups such as the Suzuki, Hermitage, and Rie groups, which exhibit complex periodic structures that are difficult to solve with existing quantum methods. The study delves into the structure and properties of these groups, explaining the complexity of their representations and the challenges posed by the quantum Fourier transform (QFT) in these cases. This contrasts the relative ease with which Abelian groups can be handled by quantum algorithms with the exponential complexity encountered with non-Abelian groups. The study provides a comparative analysis of the computational complexity between classical and quantum approaches to find the period in different types of groups, highlighting that while quantum algorithms offer exponential speedup for Abelian cases, non-Abelian structures remain a frontier for further research. The conclusion calls for continued research in quantum representation theory and cryptanalysis, especially for non-Abelian groups where current quantum methods have not yet provided efficient solutions. The problem of finding the period has been identified as critical to the advancement of both quantum computing and cryptographic applications.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318811 Detection of broadband signals by their spectral features 2024-12-23T23:34:30+02:00 I.E. Antipov rt@nure.ua O.M. Nikitin rt@nure.ua <p>The paper is about a method for detecting wideband signals on a noise background, which uses the symmetry property of its spectrum. The authors of the article proposed the method. An analysis of literary sources has shown that the detection of WBS is relevant for electronic warfare and information security tasks, and the speed of detection is very important. Also, based on a literature review, it was concluded that the energy detection method is not effective enough, including due to the need for long-term accumulation of signal energy. As the SNR deteriorates, the required accumulation time increases. In paper proposes to use the fact that the energy spectra of most WBS, in particular phase-shifted one, are symmetrical with respect to their central frequency.</p> <p>The proposed method involves applying a Fast Fourier Transform to the analyzed mixture of signal and noise. Next, a function is equal to the sum of the products of spectral samples taken symmetrically with respect to the expected central frequency calculated. It is analytically shown that such processing makes it possible to detect the PM WBS on a white Gaussian noise background of based on the characteristic maximum of this function. If this function is calculated only for noise (without a signal), then the maximum does not arise, since white noise has a uniform spectral density.</p> <p>If the value of the average frequency of the signal is not known, then, according to the proposed algorithm, it is necessary to perform several cycles of calculations for different estimated average frequencies. Thus, both the presence of a signal in the mixture and the value of its central frequency are detected. Computer modeling, the results of which are also presented in the paper, shows that the use of the proposed method can reduce the accumulation time and increase resistance to noise exposure, compared to the energy detection method.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318812 Mathematical model of the location channel of the contour of the adaptation of radioacoustic atmospheric sounding systems 2024-12-23T23:47:33+02:00 A.V. Kartashov rt@nure.ua <p>The system of radio acoustic sounding (RAS) of the atmosphere is used in the process of solving actual scientific and applied tasks to ensure flights of aircraft, weather forecasting, studying the atmosphere, etc. However, the effectiveness of the existing radio-acoustic means is insufficient and there are practical needs for developing more promising structures and algorithms that will be implemented during the construction of specific types of sounding stations. Among the existing limitations of radio acoustic sounding systems, the main one is the violation of the Bragg condition, which determines the ratio between the lengths of acoustic and electromagnetic waves.</p> <p>The article considers the method of adapting RAS systems by changing the frequency of the sounding radio signal in order to fulfill the Bragg condition as the emitted acoustic pulse signal moves along the sounding path. It is shown that to increase the efficiency of the frequency adaptation method, it is necessary to use an adequate mathematical model of the information location channel, which describes the main features of the scattering of radio waves on the acoustic wave parcel, in the control circuit of the frequency of the sounding radio signal.</p> <p>The mathematical model of the location channel is considered. The study of the main types of probing acoustic and electromagnetic signals was performed using scattering bodies in the spectral representation. It has been revealed that in the presence of the Bragg condition detuning, the spectrum of the radio signal scattered on the sound has an asymmetric shape, and this is the main reason for the appearance of systematic errors in the results of sound speed measurements. Eliminating the identified errors will improve the efficiency of the adaptation devices and the RAS system as a whole.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318817 Status and prospects for the use of diagnostic tools based on the method of gas-discharge visualization 2024-12-24T00:03:46+02:00 O.M. Zinchenko rt@nure.ua V.P. Oliinyk rt@nure.ua P.M. Podpruzhnykov rt@nure.ua <p>Diagnostic tools based on the gas-discharge visualization method were created for scientific and applied research of biological and non-biological objects, the state of the environment. The diagnostic essence of the method is the connection of the glow of an electric discharge around the object in the atmospheric air with the electrophysical properties of the internal and surface structures of the object, which in turn are interpreted as medical and biological indicators for living organisms, or technical characteristics for non-living ones structures. With the help of these tools, you can diagnose the human body, study liquids and materials of organic and inorganic origin. The disadvantages of the method include the dependence of informative indicators of discharge images not only on the properties of the object, but also on the constancy of the parameters of the surrounding environment. There are no uniform metrological requirements for the technical means of gas discharge visualization, which prevents their practical application. The purpose of the research is to find technical solutions for the construction of gas-discharge visualization tools to achieve the potential possibilities of their practical application. The analysis of the physical and technical conditions of gas-discharge visualization showed that with the relative constancy of the physical regularities of the discharge, the modes of measurement of the informative indicators of the images in these means differ significantly (amplitude, frequency, duration, form of alternating voltage). The known designs differ in the type of sensor, method and device of primary radiation registration, algorithms for reproduction and processing of the diagnostic image. It is proposed to standardize the technical characteristics of these tools and algorithms for obtaining informative indicators to compare correctly the diagnostic results obtained by different researchers (especially in the medical field). It is advisable to expand the use of gas-discharge visualization tools for controlling the composition of technical liquids, non-destructive flaw detection of materials and structures. It is recommended to add information about the characteristics of the surrounding atmospheric air (temperature, humidity, pressure) when conducting diagnostics.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318820 Characteristics of a controlled Bragg reflection waveguide with gyrotropic cladding 2024-12-24T00:29:02+02:00 Y.Y. Demydenko rt@nure.ua V.V. Novytskyi rt@nure.ua Y.M. Odarenko rt@nure.ua O.O. Shmat’ko rt@nure.ua <p>A planar Bragg waveguide with a hollow channel, the cladding of which contains periodically arranged dielectric and gyrotropic ferrite layers, has been theoretically investigated. A two-dimensional model of the waveguide is developed taking into account the frequency dependence of the components of the magnetic permeability tensor of gyrotropic layers. Results of numerical calculations (using the finite element method) show regularities of influence of the external magnetic field (pointed to the direction transverse to the longitudinal axis of the structure) induction on the dispersion characteristics of the Bragg waveguide cladding and its spectral characteristics. The orientation of the external magnetic field corresponds to the Voigt configuration. An increase in the induction of the magnetic field leads to a significant transformation of the band gap of the waveguide channel cladding. There is an increase in its width and a shift towards higher frequencies. The results of the calculations of the spectral characteristics indicate the corresponding changes that occur in the frequency band of the Bragg waveguide. It is shown that the increase in the width of the transmission zone of the waveguide occurs mainly in the high-frequency region of the considered part of the spectrum. The calculated spatial distribution of the electric field in the studied structure indicates a high degree of localization of electromagnetic energy in the hollow waveguide channel within its transmission zone. This makes it possible to simplify the model of the studied structure due to the exclusion from consideration of losses in gyrotropic layers. On the basis of controlled Bragg waveguides, a variety of functional devices in the microwave and optical ranges can be developed, the operating characteristics of which change under the influence of an external magnetic field.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318821 Development of a model of a biomedical system of vital activity under the influence of electromagnetic radiation 2024-12-24T00:44:27+02:00 V.V. Semenets rt@nure.ua T.E. Stytsenko rt@nure.ua A.B. Grigoriev rt@nure.ua <p>An assessment of the effectiveness of the biomedical protection system has been developed based on the assessment of the dose of the harmful effects of electromagnetic radiation, which allows comparing the existing technical systems according to their level of safety. A functional model of the biomedical vital system with various sources of electromagnetic radiation of the microwave range has been developed based on deterministic criteria, which allow evaluating with a certain probability the performance of the task of functioning of the vital activity system. The statistical criterion is built taking into account the cost of the system, which allows us (when building biological protection systems based on general models) to obtain calculation formulas connecting the newly defined system quality criterion with parameters that can be relatively easily measured and normalized from biological and sanitary considerations, which determines the practical value of the work.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024 http://rt.nure.ua/article/view/318823 Model for estimating the linear electron density of the trail created by a meteoroid 2024-12-24T00:58:38+02:00 O.V. Holovan rt@nure.ua V.M. Kharchenko rt@nure.ua <p>An assessment of the linear electron density of the trail (LEDTr) created by a meteoroid when passing through the Earth's atmosphere at a given observation altitude is used to calculate the power of the received radio signal and predict the reflectivity of the trail in the process of its further transformation.</p> <p>In the published works, the formulas for calculating the LEDTr do not show its relation to altitude, and there are no explicitly specified parameters of the meteoroid body and atmosphere.</p> <p>When developing the presented model for estimating LEDTr, the main physical processes occurring during the interaction of a meteoroid with atoms and molecules of the atmosphere were taken into account. The proposed calculation of the LEDTr includes an assessment of the midsection of the meteoroid's head, the concentration of particles (numerical density) in the atmosphere, and the value of the integral ionization coefficient at the observation altitude. The necessary calculation formulas were obtained, and a software-implemented calculation algorithm was presented.</p> <p>Unlike to the well-known formulas for calculating LEDTr and semi-empirical models obtained by fitting to the results of radar observations, the presented technique allows calculations to be carried out for explicitly specified parameters of the meteoric body and atmosphere. It is important to note that when estimating the mass loss of the meteoroid, a recurrent method was used to calculate the mass and velocity as its altitude changed. This method made it possible to take into account changes in the mass and midsection of the meteoroid during its movement. The obtained relation of LEDTr to altitude corresponds well to the luminosity curves of the meteor trail, and the value of the electron density at the ionization maximum corresponds to the known observational results.</p> <p>Estimating the LEDTr for a given (measured) reflection point makes it possible to calculate the amplitude-time characteristics (ATCH) of radio signals, which allows for the creation of a model image of a scattered signal. Comparison of the ATCH of the received signal with the calculated model images allows one to make informed assumptions about the characteristics of the meteoroid that generated the ionized trail.</p> 2024-09-26T00:00:00+03:00 Copyright (c) 2024