Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.09
V. Zhyrnov, S. Solonskaya, I. Shubin
The paper presents results of development of the method and experimental studies of the system for automatic detection of radar signals of aerial objects and their recognition with the processing of real records in surveillance radars. The relevance of this work consists in creation of algorithms for automatic information processing to ensure effective detection of useful signals due to accumulation of signal (energy) and semantic information. The method is based on the definition of semantic components at the stage of formation and analysis of the symbolic model of signals from point and extended air objects. Signal information is described by the predicate function of process knowledge of the formation and analysis of a symbolic model of a burst of impulse signals from point-like mobile aircraft such as an airplane, a helicopter, a UAV, and from extended atmospheric formations such as angel-echoes, clouds. As a result of semantic analysis of symbolic images of signal marks, classification distinctive features of air objects were obtained. The semantic components of the decision-making algorithm, similar to the decision-making algorithms used by the operator, have been investigated. In the developed algorithm, signal information is described by a predicate function on the set of signal mark pulse amplitudes that have exceeded a certain threshold value. Recognizing of aerial objects is carried out by solving the developed equations of predicate operations. The verification of the developed method was carried out on real data obtained on a survey radar of the centimeter range (pulse duration was 1 μs, probing frequency wass 365 Hz, survey period was 10 s). Based on these data, the types of characteristic marks of radar signals are modeled. According to the results of the experiments, they were all correctly identified.
{"title":"Evaluation of radar image processing efficiency based on intelligent analysis of processes","authors":"V. Zhyrnov, S. Solonskaya, I. Shubin","doi":"10.30837/rt.2021.4.207.09","DOIUrl":"https://doi.org/10.30837/rt.2021.4.207.09","url":null,"abstract":"The paper presents results of development of the method and experimental studies of the system for automatic detection of radar signals of aerial objects and their recognition with the processing of real records in surveillance radars. The relevance of this work consists in creation of algorithms for automatic information processing to ensure effective detection of useful signals due to accumulation of signal (energy) and semantic information. The method is based on the definition of semantic components at the stage of formation and analysis of the symbolic model of signals from point and extended air objects. Signal information is described by the predicate function of process knowledge of the formation and analysis of a symbolic model of a burst of impulse signals from point-like mobile aircraft such as an airplane, a helicopter, a UAV, and from extended atmospheric formations such as angel-echoes, clouds. As a result of semantic analysis of symbolic images of signal marks, classification distinctive features of air objects were obtained. The semantic components of the decision-making algorithm, similar to the decision-making algorithms used by the operator, have been investigated. In the developed algorithm, signal information is described by a predicate function on the set of signal mark pulse amplitudes that have exceeded a certain threshold value. Recognizing of aerial objects is carried out by solving the developed equations of predicate operations. The verification of the developed method was carried out on real data obtained on a survey radar of the centimeter range (pulse duration was 1 μs, probing frequency wass 365 Hz, survey period was 10 s). Based on these data, the types of characteristic marks of radar signals are modeled. According to the results of the experiments, they were all correctly identified.","PeriodicalId":41675,"journal":{"name":"Visnyk NTUU KPI Seriia-Radiotekhnika Radioaparatobuduvannia","volume":"20 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73878336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.12
V. Kartashov, V.A. Pososhenko, V. Kolesnik, I.S. Seleznjov, R.I. Bobnev, A. Kapusta
The problem of UAV radar monitoring by its acoustic radiation is considered. It is shown that in a number of practical cases such an approach is preferable to observation by radar methods directly from the UAV airframe. It is noted that the radio signals scattered by acoustic packets from the UAV are characterized by an unknown in advance complex envelope, which does not allow the use of optimal filtering methods for their detection and estimation. It is shown that to solve these problems, it is advisable to use the principle of accumulation over the observation interval of the energy of a narrow-band random process reduced to the noise dispersion, using the statistical differences between noise fluctuations and the additive "signal-plus-noise" mixture. It is shown that the energy estimate reduced to noise has either a central or an off-center "chi-square" distribution with a certain number of degrees of freedom and an off-center parameter greater than or equal to zero. As a result of comparing the current value of the no centrality parameter with the threshold value, a decision is made on the presence or absence of a useful signal in the observation interval with minimal a priori information about its parameters. It is noted that the well-known expressions for the differential probability densities of the central and non-central chi-square distributions allow one to obtain qualitative estimates of the synthesized detector. A practical structural diagram of a detector using processing of received oscillations in quadrature channels is proposed.
{"title":"Detection of radar signals scattered by acoustic disturbances generated by UAVs","authors":"V. Kartashov, V.A. Pososhenko, V. Kolesnik, I.S. Seleznjov, R.I. Bobnev, A. Kapusta","doi":"10.30837/rt.2021.4.207.12","DOIUrl":"https://doi.org/10.30837/rt.2021.4.207.12","url":null,"abstract":"The problem of UAV radar monitoring by its acoustic radiation is considered. It is shown that in a number of practical cases such an approach is preferable to observation by radar methods directly from the UAV airframe. It is noted that the radio signals scattered by acoustic packets from the UAV are characterized by an unknown in advance complex envelope, which does not allow the use of optimal filtering methods for their detection and estimation. It is shown that to solve these problems, it is advisable to use the principle of accumulation over the observation interval of the energy of a narrow-band random process reduced to the noise dispersion, using the statistical differences between noise fluctuations and the additive \"signal-plus-noise\" mixture. It is shown that the energy estimate reduced to noise has either a central or an off-center \"chi-square\" distribution with a certain number of degrees of freedom and an off-center parameter greater than or equal to zero. As a result of comparing the current value of the no centrality parameter with the threshold value, a decision is made on the presence or absence of a useful signal in the observation interval with minimal a priori information about its parameters. It is noted that the well-known expressions for the differential probability densities of the central and non-central chi-square distributions allow one to obtain qualitative estimates of the synthesized detector. A practical structural diagram of a detector using processing of received oscillations in quadrature channels is proposed.","PeriodicalId":41675,"journal":{"name":"Visnyk NTUU KPI Seriia-Radiotekhnika Radioaparatobuduvannia","volume":"5 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90889611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.14
S. P. Serhiienko, V. Krizhanovski, D. Chernov, L. Zagoruiko
The use of noise interference has become a common practice for information security. Recently appeared publications showing a potential possibility to use the noise radio frequency interference for information skimming by passive radio eavesdropping device. In particular, the vulnerability of the premises protected from eavesdropping devices is increased, if the radio frequency noising is switched on when confidential negotiations are being conducted. The use of radio noise waves energy for eavesdropping makes such devices invisible to nonlinear locators for listening devices if they activated only by noise signals. The paper shows that the use of non-steady state noise allows counteracting the unauthorized pickup of information. The analysis of non-steady state radio frequency noise effectiveness was carried out using the correlation receiver model. The correlation receiver has the highest sensitivity, and it works more efficiently with noise-like signals. It is shown that for counteracting the information pickup, it is necessary to use a noise, amplitude modulated by a random signal, whose spectrum coincides with a spectrum of a potential informational signal. Imposition a more powerful modulation noise to a weak informational signal makes impossible the information transfer. It is shown on the example of changing the power of a monochromatic signal while “beetle” transmits using steady-state and non-steady state noises, that due to the signal energy parametric redistribution over the non-steady-state noise modulation spectrum, the power of monochromatic signal is reduced by more than 10 dB compared to the transmission of the same signal using a steady-state noise. It can be concluded that the use of non-steady state noise signals for radio frequency suppression makes impossible their use for passive eavesdropping devices operation.
{"title":"The use of non-steady state noise interferences to counteract passive eavesdropping devices","authors":"S. P. Serhiienko, V. Krizhanovski, D. Chernov, L. Zagoruiko","doi":"10.30837/rt.2021.4.207.14","DOIUrl":"https://doi.org/10.30837/rt.2021.4.207.14","url":null,"abstract":"The use of noise interference has become a common practice for information security. Recently appeared publications showing a potential possibility to use the noise radio frequency interference for information skimming by passive radio eavesdropping device. In particular, the vulnerability of the premises protected from eavesdropping devices is increased, if the radio frequency noising is switched on when confidential negotiations are being conducted. The use of radio noise waves energy for eavesdropping makes such devices invisible to nonlinear locators for listening devices if they activated only by noise signals. The paper shows that the use of non-steady state noise allows counteracting the unauthorized pickup of information. The analysis of non-steady state radio frequency noise effectiveness was carried out using the correlation receiver model. The correlation receiver has the highest sensitivity, and it works more efficiently with noise-like signals. It is shown that for counteracting the information pickup, it is necessary to use a noise, amplitude modulated by a random signal, whose spectrum coincides with a spectrum of a potential informational signal. Imposition a more powerful modulation noise to a weak informational signal makes impossible the information transfer. It is shown on the example of changing the power of a monochromatic signal while “beetle” transmits using steady-state and non-steady state noises, that due to the signal energy parametric redistribution over the non-steady-state noise modulation spectrum, the power of monochromatic signal is reduced by more than 10 dB compared to the transmission of the same signal using a steady-state noise. It can be concluded that the use of non-steady state noise signals for radio frequency suppression makes impossible their use for passive eavesdropping devices operation.","PeriodicalId":41675,"journal":{"name":"Visnyk NTUU KPI Seriia-Radiotekhnika Radioaparatobuduvannia","volume":"102 41 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77630205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.13
M. Tkach
Secondary radar systems for monitoring airspace play a significant role in the information support of airspace control systems and air traffic control. These systems provide radar surveillance of airborne objects equipped with aircraft transponders and provide two-way communication via data request and response channels between ground radar stations and airborne objects. The paper assesses the relative throughput of aircraft transponders of secondary radar systems for monitoring airspace under the influence of correlated and uncorrelated interference in the request channel. The assessment of the throughput of the aircraft transponder shows that the aircraft transponder does not reach the maximum load included in the existing identification system under the influence of deliberate correlated interference. This indicates a sub-optimal determination of the aircraft transponder load factor of the existing secondary radar system. Incorrect determination of the maximum load of the aircraft transponder leads to a decrease in the noise immunity of both the aircraft transponder and the entire secondary radar system. At the same time, it should be noted that the interested party has the possibility of unauthorized use of an aircraft transponder to obtain information or paralyze the latter when applying interference of the required intensity.
{"title":"Estimation of the relative throughput of aircraft transponders of secondary airspace surveillance radar systems","authors":"M. Tkach","doi":"10.30837/rt.2021.4.207.13","DOIUrl":"https://doi.org/10.30837/rt.2021.4.207.13","url":null,"abstract":"Secondary radar systems for monitoring airspace play a significant role in the information support of airspace control systems and air traffic control. These systems provide radar surveillance of airborne objects equipped with aircraft transponders and provide two-way communication via data request and response channels between ground radar stations and airborne objects. \u0000The paper assesses the relative throughput of aircraft transponders of secondary radar systems for monitoring airspace under the influence of correlated and uncorrelated interference in the request channel. The assessment of the throughput of the aircraft transponder shows that the aircraft transponder does not reach the maximum load included in the existing identification system under the influence of deliberate correlated interference. This indicates a sub-optimal determination of the aircraft transponder load factor of the existing secondary radar system. Incorrect determination of the maximum load of the aircraft transponder leads to a decrease in the noise immunity of both the aircraft transponder and the entire secondary radar system. At the same time, it should be noted that the interested party has the possibility of unauthorized use of an aircraft transponder to obtain information or paralyze the latter when applying interference of the required intensity.","PeriodicalId":41675,"journal":{"name":"Visnyk NTUU KPI Seriia-Radiotekhnika Radioaparatobuduvannia","volume":"87 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77865019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.08
Y. Kotukh, V. Lyubchak, O. Strakh
The current level of development of engineering and technology is characterized by a constant expansion of the variety and complexity of mechanical and controlled objects, the operation of which occurs in a continuous-discrete time mode. One of these objects is the process of spreading malicious software in wireless sensor networks, the constant growth of trends towards which is due to their use as a single type of self-organized data transmission network with the least labor intensity and low cost. The concept of building sensor networks has not been formed at all. Therefore, the study of certain properties of such networks is very important for both domestic and world science. Moreover, for the strategically important sectors of the country, in particular defense, the protection of wireless sensor networks is a very important component. A new model of malware distribution is proposed, which is described by some boundary value problem for an impulsive dynamical system on a time scale.
{"title":"One approach to the design of individual mathematical models of security in wireless sensor networks","authors":"Y. Kotukh, V. Lyubchak, O. Strakh","doi":"10.30837/rt.2021.4.207.08","DOIUrl":"https://doi.org/10.30837/rt.2021.4.207.08","url":null,"abstract":"The current level of development of engineering and technology is characterized by a constant expansion of the variety and complexity of mechanical and controlled objects, the operation of which occurs in a continuous-discrete time mode. One of these objects is the process of spreading malicious software in wireless sensor networks, the constant growth of trends towards which is due to their use as a single type of self-organized data transmission network with the least labor intensity and low cost. \u0000The concept of building sensor networks has not been formed at all. Therefore, the study of certain properties of such networks is very important for both domestic and world science. Moreover, for the strategically important sectors of the country, in particular defense, the protection of wireless sensor networks is a very important component. \u0000A new model of malware distribution is proposed, which is described by some boundary value problem for an impulsive dynamical system on a time scale.","PeriodicalId":41675,"journal":{"name":"Visnyk NTUU KPI Seriia-Radiotekhnika Radioaparatobuduvannia","volume":"52 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79821662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.03
A. Bessalov, O. Tsygankova, S. Abramov
The properties of twisted and quadratic supersingular Edwards curves that form pairs of quadratic torsion with order p+1 over a prime field Fp are considered. A modification of the CSIDH algorithm based on the isogenies of these curves instead of the traditional arithmetic of curves in the Montgomery form is presented. The parameters of these two classes of supersingular Edwards curves for p=239 are calculated and tabulated. An example of the isogenies of these curves in the implementation of the CSIDH algorithm as a non-interactive secret sharing scheme based on the secret and public keys of Alice and Bob is given. It is shown that the sequences of parameters ±d(i) of isogeny chains for quadratic and twisted supersingular Edwards curves, respectively, have a reverse nature on the period of the sequence. A recurrent algorithm for calculating the coordinates of points that form the kernels of isogenies of odd degrees is proposed, and its implementation in various coordinate systems is considered. A comparative analysis of the cost of calculating the parameter d´ of the isogenic curve E´ using the Farashakhi-Hosseini (W : Z) - coordinates and classical projective coordinates (X : Y : Z) is given. It is noted that all calculations in the CSIDH algorithm necessary to calculate the shared secret dAB are reduced only to the calculation of the isogenic curve E´ parameter d´ and are performed by field operations and the scalar multiplication of the point. The controversial issue of refusal to calculate the isogenic function ϕ(R) of a curve point R in the CSIDH algorithm is discussed.
{"title":"Estimation of the computational cost of the CSIDH algorithm on supersingular twisted and quadratic Edwards curves","authors":"A. Bessalov, O. Tsygankova, S. Abramov","doi":"10.30837/rt.2021.4.207.03","DOIUrl":"https://doi.org/10.30837/rt.2021.4.207.03","url":null,"abstract":"The properties of twisted and quadratic supersingular Edwards curves that form pairs of quadratic torsion with order p+1 over a prime field Fp are considered. A modification of the CSIDH algorithm based on the isogenies of these curves instead of the traditional arithmetic of curves in the Montgomery form is presented. The parameters of these two classes of supersingular Edwards curves for p=239 are calculated and tabulated. An example of the isogenies of these curves in the implementation of the CSIDH algorithm as a non-interactive secret sharing scheme based on the secret and public keys of Alice and Bob is given. It is shown that the sequences of parameters ±d(i) of isogeny chains for quadratic and twisted supersingular Edwards curves, respectively, have a reverse nature on the period of the sequence. A recurrent algorithm for calculating the coordinates of points that form the kernels of isogenies of odd degrees is proposed, and its implementation in various coordinate systems is considered. A comparative analysis of the cost of calculating the parameter d´ of the isogenic curve E´ using the Farashakhi-Hosseini (W : Z) - coordinates and classical projective coordinates (X : Y : Z) is given. It is noted that all calculations in the CSIDH algorithm necessary to calculate the shared secret dAB are reduced only to the calculation of the isogenic curve E´ parameter d´ and are performed by field operations and the scalar multiplication of the point. The controversial issue of refusal to calculate the isogenic function ϕ(R) of a curve point R in the CSIDH algorithm is discussed.","PeriodicalId":41675,"journal":{"name":"Visnyk NTUU KPI Seriia-Radiotekhnika Radioaparatobuduvannia","volume":"11 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86742247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.04
V.V. Dubina, R. Oliynykov
This paper presents the results of a study of the properties of transactions formation and processing of in blockchain systems, aimed to identify existing barriers to the secure functioning of the network, processing and transmission of data between users, and to determine possible means of deanonymizing transactions. The anonymity of the network is one of the reasons for cryptocurrencies popularity and widespread use of blockchain technology. However, its presence is the basis for unscrupulous transactions, criminal actions of fraudsters and attacks on the system. Therefore, one of the main issues today is to ensure the reliable storage of information and the ability to track suspicious activity and timely protection of users in blockchain systems. The article examines known methods of increasing anonymity and maintaining confidentiality in modern networks based on the principles of blockchain technology, the threats arising from their use and the possible ways of tracking the actions of system participants. A comparative description of known tracking tools and possible means of de-anonymization of the history of completed transactions is given. As a result of the study, it was proposed to use a separate platform to analyze the network in real time, identify threats and their timely elimination, with the ability to visualize relationships and build address graphs as a result of tracking the entire chain of transactions. The tool makes it possible to implement a search among cryptocurrency addresses, blocks, transactions and tags, as well as to identify clusters associated with a particular address. The system analyzes the network in real time to gain insight into the statistics. Particular attention is paid to detecting so-called anomalies, i.e., the identification of transactions that deviate from standard structures. This allows identifying and tracking potentially malicious activities at an early stage.
{"title":"Methods and means of deanonymization of transactions in blockchain","authors":"V.V. Dubina, R. Oliynykov","doi":"10.30837/rt.2021.4.207.04","DOIUrl":"https://doi.org/10.30837/rt.2021.4.207.04","url":null,"abstract":"This paper presents the results of a study of the properties of transactions formation and processing of in blockchain systems, aimed to identify existing barriers to the secure functioning of the network, processing and transmission of data between users, and to determine possible means of deanonymizing transactions. The anonymity of the network is one of the reasons for cryptocurrencies popularity and widespread use of blockchain technology. However, its presence is the basis for unscrupulous transactions, criminal actions of fraudsters and attacks on the system. Therefore, one of the main issues today is to ensure the reliable storage of information and the ability to track suspicious activity and timely protection of users in blockchain systems. The article examines known methods of increasing anonymity and maintaining confidentiality in modern networks based on the principles of blockchain technology, the threats arising from their use and the possible ways of tracking the actions of system participants. A comparative description of known tracking tools and possible means of de-anonymization of the history of completed transactions is given. As a result of the study, it was proposed to use a separate platform to analyze the network in real time, identify threats and their timely elimination, with the ability to visualize relationships and build address graphs as a result of tracking the entire chain of transactions. The tool makes it possible to implement a search among cryptocurrency addresses, blocks, transactions and tags, as well as to identify clusters associated with a particular address. The system analyzes the network in real time to gain insight into the statistics. Particular attention is paid to detecting so-called anomalies, i.e., the identification of transactions that deviate from standard structures. This allows identifying and tracking potentially malicious activities at an early stage.","PeriodicalId":41675,"journal":{"name":"Visnyk NTUU KPI Seriia-Radiotekhnika Radioaparatobuduvannia","volume":"49 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73541566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.16
G. Komarova
Using the method of physical modeling, an algorithm for calculating the force with which a standing electromagnetic wave acts on a ferrite sphere of arbitrary diameter placed in a constant magnetic field is obtained. The value of constant magnetic field intensity provides appearance of ferrimagnetic resonance. Dependence of the magnetic field of an electromagnetic wave in the middle of a ferrite sphere on the size of its resonant radius and spherical coordinates are studied. In the center of the ferrite sphere, the resonance radius of which is 4.2634 mm, the microwave magnetic field strength is 83796 times greater than the magnetic field strength in the incident plane polarized wave. Mean-square value of the magnetic field strength over the volume of the sphere increases 4.8 times. Standing wave, formed in a free space with power flow density of 622 kW/m2 and wavelength of 3.2 cm, reflects from metallic shield placed at a distance of λo/8 + nλo/2, n = 0, 1, 2, 3… measured from the center of ferrite sphere and impacts with force of 0,12 N on ferrite sphere with resonance radius of 4,2634 mm. The results of the calculated force acting on the YIG – resonator coincide with the experimental results given in the well-known works (the power flux density is 43 kW/m2, the radius of the ferrite sphere is 1.775 mm, the force is 6 ± 0.5 μN) within the measurement error. Application of spatial resonance, standing electromagnetic wave and YIG resonator allows to increase of energy conversion factor of microwave energy conversion into mechanic one 8,6·104 times in compare to application of ferrite cylinder only in known papers. The research results can be used by the developers of converters of microwave energy into mechanical energy.
{"title":"Influence of ferrimagnetic resonance on conversion of electromagnetic energy by a YIG resonator into mechanical one","authors":"G. Komarova","doi":"10.30837/rt.2021.4.207.16","DOIUrl":"https://doi.org/10.30837/rt.2021.4.207.16","url":null,"abstract":"Using the method of physical modeling, an algorithm for calculating the force with which a standing electromagnetic wave acts on a ferrite sphere of arbitrary diameter placed in a constant magnetic field is obtained. The value of constant magnetic field intensity provides appearance of ferrimagnetic resonance. Dependence of the magnetic field of an electromagnetic wave in the middle of a ferrite sphere on the size of its resonant radius and spherical coordinates are studied. In the center of the ferrite sphere, the resonance radius of which is 4.2634 mm, the microwave magnetic field strength is 83796 times greater than the magnetic field strength in the incident plane polarized wave. Mean-square value of the magnetic field strength over the volume of the sphere increases 4.8 times. Standing wave, formed in a free space with power flow density of 622 kW/m2 and wavelength of 3.2 cm, reflects from metallic shield placed at a distance of λo/8 + nλo/2, n = 0, 1, 2, 3… measured from the center of ferrite sphere and impacts with force of 0,12 N on ferrite sphere with resonance radius of 4,2634 mm. The results of the calculated force acting on the YIG – resonator coincide with the experimental results given in the well-known works (the power flux density is 43 kW/m2, the radius of the ferrite sphere is 1.775 mm, the force is 6 ± 0.5 μN) within the measurement error. Application of spatial resonance, standing electromagnetic wave and YIG resonator allows to increase of energy conversion factor of microwave energy conversion into mechanic one 8,6·104 times in compare to application of ferrite cylinder only in known papers. The research results can be used by the developers of converters of microwave energy into mechanical energy.","PeriodicalId":41675,"journal":{"name":"Visnyk NTUU KPI Seriia-Radiotekhnika Radioaparatobuduvannia","volume":"100 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2021-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85803991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-24DOI: 10.30837/rt.2021.4.207.15
D. Gorelov, O. Ivanova, O.V. Lytvynenko, A.A. Dovbnia, D.O. Minin
When using distance education systems, the problem of information security of the educational process arises, which, in addition to external ones, also implies internal threats. One of these threats can be a legitimate user who paid a fraudster to take tests and give visibility to educational activities under his own name. The use of traditional identification methods has two significant drawbacks: firstly, the ambiguity of the identified user, because the identification of the user occurs by the entered pair login-password; secondly, the inability to detect the substitution of an identified user in the process of working with the system. These disadvantages are eliminated by using biometric methods of covert and continuous monitoring. In the first part of the work the different types of control knowledge tests are analyzed. Taking into account the specifics of the use of covert keyboard monitoring algorithms, the following is proposed: 1) to use tests that do not contain answers; 2) use tests after each learning activities in order to form a user’s biometric vector; 3) use tests with numerical answers in order to minimize the analyzed keystroke digraphs. An algorithm for user’s profile formation and its identification is proposed in the second part of the work. Its combine qualitative (distribution of the frequencies of using numeric keys groups, comma-separated keys, “plus” and “minus” keys on the main and additional keyboard units) and quantitative (analysis of statistical properties of keystroke digraphs) approaches. The experimentally obtained estimates of the identification accuracy of the proposed algorithm: FAR=4.64% and FRR=6.25%.
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Pub Date : 2021-09-24DOI: 10.30837/rt.2021.3.206.10
V. Zhyrnov, S. Solonskaya, V. Zarytskyi
The article discusses a method for dealing with non-stationary natural and simulating interference in intelligent surveillance radars. When creating simulating marks, the introduction of amplitude modulation into the relayed radar sounding signal is used. As a result of the analysis, it was possible to find out that in the imitating noise, in this case, the so-called "intelligent" fluctuations of the burst structure of false marks appear, which differ from the fluctuations of the packs of real marks and can be easily detected by a human operator. The method is based on the definition of semantic components at the stage of formation and analysis of a symbolic model of amplitude fluctuations of a burst of signals from non-stationary natural and simulating interference and from real moving objects. In this case, the semantic features of amplitude fluctuations are determined by solving predicate equations for transforming these fluctuations into symbolic images of noise marks and real mobile aircraft. As a result of semantic analysis of the amplitude fluctuations of the burst in the time domain, classification distinctive features of fluctuations in the burst of signals from natural imitating noise and air objects were obtained. The semantic components of the decision-making algorithm are investigated, which are similar to the decision-making algorithms by a human operator. Process knowledge of transforming radar signals into symbolic images of amplitude fluctuations of a burst in the time domain is formalized. The formalization of the processing of symbolic images includes a system of predicate equations, by solving which the types of amplitude fluctuations of the burst are identified. Based on the results of experimental data, the transformations of real radar signals into symbolic images of burst fluctuations were carried out on the basis of the algebra of finite predicates. The authors also managed to propose these transformations to be used as the basis of an effective toolkit for obtaining classification distinctive features of packet fluctuations from interference and from aircraft.
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