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• FORMATION OF A SINGLE SIDEBAND QUADRATURE PHASE SHIFT KEYING OF RADIO SIGNALS AT SUB-CARRIER FREQUENCIES IN A COHERENT OPTICAL COMMUNICATION SYSTEM

  А.М. Mahmood Hussein, К. Е. Rumyantsev

  2023-02-17

  Abstract ▼

  The coherent optical communication technology allows to create a transmission system over
  long distances with high bandwidth. Higher order modulation formats such as Quadrature Phase
  Shift Keying (QPSK) provide high data rates in a simple, reliable and cost-effective manner. These
  multi-bit modulation methods are transmitted as a symbol implementing simple in-phase and
  quadrature (IQ) modulation formats. To increase throughput in coherent optical systems, optical
  subcarrier multiplexing is used, when several radio signals are multiplexed on one optical carrier.
  This multiplexing is limited by double sideband, resulting in reduced received subcarrier power
  and degraded carrier-to-noise ratio. To accumulate these effects, many ways of implementing
  optical single sideband (OSSB) are proposed. The paper proposes an analysis of a coherent optical
  transmission system for generating single-sideband QPSK modulation using an optical I/Q
  modulator and M-ary RF pulse shaping. The pseudo-random bit sequence generator generates a
  10 Gb/s modulation baseband signal. Each bit sequence is converted into an M-ary sequence of
  symbols from binary signals using phase shift keying (PSK). The M-ary pulse generator generates
  a multi-level pulse shaping according to the sequence of M-ary input symbols. Electrical pulses
  are applied to the electrodes of the electro-optical modulator according to the Mach–Zehnder
  interferometer (MZM) scheme. The I/Q modulator operated at the quadrature operating point in
  both the in-phase and quadrature branches, with an extinction ratio 60 dB and 3 V switching voltage.
  The light wave is emitted by a CW laser with a wavelength of 1550 nm.

• METHODS OF OBTAINING INFORMATION ABOUT THE THREE-DIMENSIONAL SCENE TO SOLVE PROBLEMS OF DETERMINING THE SPATIAL POSITION OF OBJECTS WITH A REGULAR STRUCTURE

  P.S. Serdyukov, К. Е. Rumyantsev

  2023-02-27

  Abstract ▼

  In this paper the basic methods of determining the coordinates of cylindrical objects to control
  the geometric parameters of an object with a regular structure are considered. Predominantly
  the considered methods are used in determining the parameters of fuel rods (installations) of fuel
  assemblies at a nuclear power plant. The purpose of this work is to analyze the existing methods
  for determining the geometric parameters of objects with regular structure. To achieve this goal, it
  is necessary to solve the following problem - to compare and conduct a study of existing methods
  for determining the geometric position of objects with a regular structure and to identify their measurement based on a particular method. Comparative analysis included a description of existing
  contact and non-contact methods (measurements of linear dimensions of three-dimensional
  objects, measurements of geometric parameters of an object in space and a device for its implementation
  and three different methods of controlling linear dimensions of three-dimensional objects
  by three Cartesian coordinates). The following tool was used for the determination - the object
  under study was photographed by one video camera on a radiation-resistant CCD from two
  defined points in space. The image points of the object were identified on the obtained images.
  Then, using the data on atomic rector dimensions and video camera parameters, we calculated the
  spatial coordinates of the object points in the object coordinate system and the elements of external
  orientation of the images. The approximate values of the unknowns needed to solve the problem
  were determined in advance, using the methods known in photogrammetry. The analysis
  showed that the most effective are non-contact methods based on processing images of the scene
  formed by video cameras based on mosaic photodetectors. Thus, measuring systems based on
  television sensors (video cameras) are the most expedient for measuring the height difference of
  an ordered sequence of cylindrical objects. The considered mathematical model has allowed to
  define a methodical error of measurement of geometrical parameters by reconstruction of a threedimensional
  scene on a series of images in conditions of the non-contact definition, caused by
  imperfection of the defined measuring method or the simplifications admitted at measurements.
  On the basis of the obtained data, it is possible to determine the center of gravity of the fuel assembly
  head, for which the methodological error is minimal, and, accordingly, to take it as a basis,
  relative to which to calculate the height difference of all steel heads of fuel assembly.

• STUDY OF THE MINIVERSION PROPERTIES IN THE PSEUDO-RANDOM FUNCTION PCOLLAPSER

  S.V. Polikarpov, V.А. Prudnikov, К. Е. Rumyantsev

  2023-02-27

  Abstract ▼

  The aim of the work is to evaluate the cryptographic properties of the pCollapser family of pseudo-
  random functions (PRF) based on the study of the properties of its mini_pCollapser_12x12 miniversion
  using fixed substitutions with extremely low cryptographic properties. As a comparison element,
  we used a mini-version of a typical function based on an SP-net, containing a similar number of fixed
  substitutions, and having a similar input/output dimension equal to 12 bits. To achieve this goal, the
  following tasks were solved: – determination of the structure of the studied functions and the number of
  rounds; – definition of a model for the formation of fixed substitutions with extremely low cryptographic
  properties; – generation of sets of 6-bit fixed substitutions with extremely low cryptographic properties; – inclusion of the substitutions obtained into the functions under study and determination of the main
  cryptographic properties of functions – the maximum dominance value for individual key values and the
  maximum dominance value averaged over the entire set of keys, the maximum and averaged over the
  entire set of keys value in the difference distribution table, algebraic degree and algebraic immunity;
  – analysis of the obtained results. The paper presents two models for the formation of fixed substitutions
  with extremely low cryptographic properties – based on the mixing of cell values in a pre-filled table
  and based on the simplest ARX function (consisting of modulo addition, cyclic shift and XOR). The use
  of fixed substitutions with extremely low non-linearity makes it possible to estimate how complex (nonlinear)
  the function under study is and what minimum level of non-linearity is necessary to effectively
  destroy the statistical dependencies between input/output data. In addition, it becomes clear that ARX
  functions can be used as non-linear elements, which often have controversial and clearly low cryptographic
  properties, but allow creating high-speed software and hardware implementations. It has been
  determined that the PRF pCollapser mini-version, in contrast to the typical function based on the SP
  network, makes it possible to obtain a high-quality non-linear function from the set of ARX-functions
  with extremely low cryptographic properties, given that no other non-linear elements are presented in
  pCollapser. The obtained results reflect the existence of a fundamental difference between the
  pCollapser PRF and a typical SP-network based PRF and confirm the correctness of the concept of
  PD-sbox pseudo-dynamic substitutions and the pCollapser function consisting of them as a whole.

• PROBABILISTIC CHARACTERISTICS OF THE SYNC DETECTION ALGORITHM BASED ON THE SELECTION OF AN ADJACENT PAIR OF SEGMENTS WITH THE MAXIMUM TOTAL COUNT

  К.Е. Rumyantsev, P.D. Mironova

  2023-08-14

  Abstract ▼

  An algorithm for detecting sync signals based on the selection of an adjacent pair of segments
  with the maximum total count is proposed. This algorithm takes into account the shortcomings
  of an alternative algorithm for detecting a sync signal based on comparing the sum of samples
  from an adjacent pair of segments with a threshold level, consisting in the need to know the level of background and noise influence, which determines the threshold level and the probability
  of erroneous detection of a signal pair of segments. The dependence of the probability of an error
  in detecting a sync pulse on the average number of signal photons in a sync pulse is studied for
  various values of the number of segments in a time frame. Thus, the probability of erroneous detection
  of a sync pulse during a frame decreases significantly as the average number of photons in
  a sync pulse increases. For example, by increasing the average number of signal photons in a sync
  pulse from 1 to 5, the probability of a sync detection error is reduced by a factor of 37. It should
  be noted that the number of pairs of segments has a weak effect on the probability of erroneous
  detection, which indicates a weak effect of dark current pulses on the probabilistic characteristics
  of the proposed algorithm for detecting sync signals. Analytical expressions are obtained for accurate
  and express calculation of probabilistic characteristics of detection, taking into account the
  probability of finding a sync pulse at the boundary of two adjacent segments due to the equality of
  the duration of the sync pulse and the time segment. The results of calculation using exact expressions
  for the probability of detecting a sync pulse showed that when the signal-to-noise ratio is
  equal to 10 and higher, the influence of noise pulses on the probability of detecting a sync pulse
  can be neglected. It has been noted that the greater the number of recorded events, or, in other
  words, the greater the sum of the average numbers of signal photons and dark current pulses, the
  greater the detection probability. The calculation of the probability of detecting a sync pulse using
  simplified expressions shows a slight deviation from calculations using exact formulas, which does
  not exceed 5,3%, and the calculation using approximate expressions gives an underestimated result.
  The resulting approximate analytical expressions can be used for express calculation of the
  probability of detecting a sync pulse in a pair of segments.

• CHANNEL ANALYSIS OF OPTICAL SINGLE SIDEBAND QUADRATURE PHASE SHIFT KEYING WITH SUBCARRIER RADIO SIGNAL FOR LASER SATELLITE COMMUNICATIONS UNDER ATMOSPHERIC TURBULENCE

  Hussein Ahmed Mahmood, К. Y. Rumyantsev, A. H. S. Al-Begat

  2023-10-23

  Abstract ▼

  Compared to traditional satellite radio communication, laser communication techniques
  demonstrate greater performance in terms of available data rates, and also guarantee a reduction
  in size, weight and power of the communication subsystem. In a satellite laser communication
  system, a laser source generates a narrow beam of radiation at the transmitter. A laser beam
  propagating through the atmosphere towards an optical receiver can experience large random
  fluctuations in optical intensity due to turbulence, which can lead to loss of power in the receiver
  and degrade system performance. In a subcarrier multiplexing (SCM) system, multiple information
  is electrically modulated at different radio carrier frequencies. Analog or digital signals carrying
  information may have different modulation formats. Optical single sideband radiation (OSSB) is
  typically generated using a dual drive Mach–Zehnder modulator (MZM). In the article, the analysis
  channel for optical single-sideband quadrature phase-shift keying transmitted signal was proposed
  for different distances under atmospheric turbulence conditions. The numerical results of
  laser satellite communications are based on an atmospheric altitude model of the structural characteristic
  of Hufnagel-Valley (H-V) refractive index fluctuations. The performance analysis makes
  it possible to estimate the effect of atmospheric turbulence, pointing error, and the diameter of the
  received aperture on the received power during transmission of a laser signal between a ground
  station and a satellite for a laser communication system, where the optical wave is a collimated
  beam with a wavelength of 1550 nm.

• ALGORITHM FOR THE CONSTRUCTION OF THE TRAJECTORY OF UNMANNED VEHICLES FOR MONITORING THE CONDITION OF AGRICULTURAL FIELDS

  B.V. Rumiantsev, S.V. Prokopchina, А.А. Kochkarov

  2024-04-15

  Abstract ▼

  Organizing continuous monitoring of large spaces with dynamically changing conditions and
  conditions is one of the key tasks in various areas of human life. This task is especially acute in Russia,
  taking into account its territories (lands) intended for agricultural activities. The particular importance
  of organizing continuous monitoring is also emphasized by the development of the concept and technology
  of precision farming. As a means to solve this system problem, various robotic and unmanned systems
  can be used, equipped with the necessary equipment in accordance with the local tasks of continuous
  monitoring. Continuous monitoring can only be ensured by the use of effective algorithms for constructing
  the movement trajectory of the mobile robotic and unmanned (primarily aviation) systems
  used. Increasing the efficiency of such algorithms from a mathematical point of view is always complicated
  by the cyclical nature of motion trajectories, i.e. construction of a Hamiltonian cycle. This work
  proposes a method for constructing an optimal trajectory for continuous cyclic monitoring tasks of agricultural
  fields. The method is based on finding a Hamiltonian cycle on the graph of the terrain map and
  allows for the automatic construction of an optimal closed path for any terrain map. A distinctive feature
  of the method is the use of a modified algorithm for finding Hamiltonian cycles. The algorithm can
  be scaled for maps corresponding to graphs with a large (more than 100) number of vertices, for which
  the standard brute-force algorithm for finding Hamiltonian cycles requires significantly more execution
  time than the proposed algorithm. It is shown that the algorithm used has a 17 times smaller growth
  constant in time complexity compared to the standard algorithm for finding Hamiltonian cycles. This
  allows for an increase in the number of vertices in the graph used for finding Hamiltonian cycles in
  real-time mode (0.1-100 seconds) by an order of magnitude (from 30 to 500). The developed algorithm
  can be implemented in modern unmanned monitoring systems for optimizing the trajectory of agricultural
  fields monitoring by unmanned vehicles in real-time mode, thus contributing to the dynamically
  evolving field of precision agriculture

• CURRENT PROBLEMS OF RADIOMONITORING IN THE SYSTEM OF ACTIONS TO ENSURE INFORMATION SECURITY

  А.V. Dyakov, К.Е. Rumyantsev

  2024-05-28

  Abstract ▼

  Wireless data transmission networks generate threats that cannot be protected against by means
  traditional for wired networks, because in this case it is impossible to provide equivalent security of wired
  networks due to the physical properties of the communication channel. The purpose of the article is to
  determine the actual problems that exist in ensuring information security (IS) in wireless segments of data
  networks. To achieve this goal, a selection of threats potentially realizable in wireless networks has been
  made from the information security threat bank of FSTEC of Russia. It is established that the realization of
  such threats can lead to a full set of violations of the state of IS, namely: violation of confidentiality, integrity
  and availability of information. The existing practical ways of providing IS in wireless segments of
  networks are considered. The analysis of these methods pointed out the technical possibility of creating an
  additional boundary in the system of echeloned information protection. In turn, this provides the potential
  to detect vulnerabilities and intrusions at the link layer of network communication both in local networks
  of enterprises and in large-scale public networks. In accordance with the goal, aspects of building such a
  defense frontier are grouped, related to control of the link layer of network interaction of wireless devices,
  reduction of frequency-territorial clusters and legal support. The review of publications reveals a gap
  between the existing approaches to radio monitoring and IS provision, and also reveals poor development
  of the direction related to research in the field of detection and prevention of wireless intrusions. The obtained
  result indicates the need to revise the existing concept of radio monitoring and develop appropriate
  organizational and technical measures for its integration into the system of measures to ensure IS, which
  should help to solve the problem of timely detection and prevention of intrusions into wireless segments of
  data networks, as well as the identification of vulnerable elements of the infrastructure of these networks.

• NEUROLINGUISTIC INFORMATION IDENTIFICATION OF INTELLIGENT SYSTEMS

  L.К. Khadzhieva, V.V. Kotenko, К.Y. Rumyantsev

  2024-08-12

  Abstract ▼

  The results of studies of the possibilities of using language and its components (text and speech) as
  factors of neurolinguistic identification and authentication of intelligent systems (IS) of native speakers of
  Russian and Chechen languages are presented. To achieve the research goals, an approach based on
  information virtualization was used. It is proposed to use one of the ways to solve the problems of increasing
  the efficiency of identification and authentication, which is the use of the factor of linguistic
  neurolinguistic text identification and authentication. Research shows, firstly, that when a language
  changes, in the case of using an intelligent system as a speaker of several languages, there is a change in
  the parameters of neurolinguistic identification, and secondly, that if all intelligent systems are native
  speakers of the same language, then when moving from one intellectual system to the other is a change in
  the parameters of neurolinguistic identification. Thus, the study determined that the language of an intelligent
  system can be used as an identification and authentication factor. IP speakers who are native speakers
  of both Chechen and Russian languages have been studied. At the first stage, ten IPs were studied as
  native speakers of the Russian language, and at the second stage, the same ten IPs were studied, but as
  native speakers of the Chechen language. The results of the dependence of the main parameters, as well as
  the dependence of the derived parameters of neurolinguistic text identification of intellectual systems of
  native speakers of Russian and Chechen languages are presented. The results obtained open up a fundamentally
  new opportunity for research in the direction of neurolinguistic text identification and authentication.
  Research in this direction is of scientific and practical interest, both for the case of identifying an
  intellectual system of native speakers of one language, and for the case when one intellectual system is a
  native speaker.

• EVOLUTION OF RADIO OVER FREE SPACE OPTICAL COMMUNICATION UTILIZING SUBCARRIER MULTIPLEXING / AMPLITUDE SHIFT KEYING

  Hussein Ahmed Mahmood, Al-Karawi Hussein Shookor, K. Y. Rumyantsev

  2021-01-19

  Abstract ▼

  The high demand for increased bandwidth, data rate and quality in optical communication
  systems in modern applications. Radio over free space optics (RoFSO) is deemed a new design
  methodology over wireless systems and networks. This technique has to ensure data rates like ones
  presented by means optical fiber communication techniques in keeping with a portion of its arrangement
  cost. Such systems are implemented by combined radio signal (RF) with optical signal,
  which containing various wireless administrations and Free Space Optics (FSO) link. In this paper,
  the simulation and evaluation system of Subcarrier Multiplexing/Amplitude Shift Keying
  (SCM/ASK) transmitter for Free Space Optical Communication is proposed. 1Gb/s data Rate given
  to the system. Whilst 10 GHz radio frequency signal setting in electrical amplitude modulator.
  Thereafter, radio signal is added with 100 subcarrier channels of 10 MHz spacing channel at
  operated first channel frequency of 60 MHz. These subcarrier channels with 900 combined with
  10 GHz sin wave signal ( radio frequency ) at hybrid coupler, the combination of each subcarriers
  and radio signal are modulated by LiNb Mach-Zehnder optical modulator with 1550 nm wavelength
  continues wave laser signal at 10 dBm input power. The optical modulated signal (after
  optical modulator) is transmitted over a various free space optical link from 300m to 1km under
  the Atmospheric turbulence effect (the structure feature of the refractive index). The system is
  evaluated utilizing Opti system software with Q-factor and BER terminology. It is shown that the
  maximum optical distance for weak turbulence (
  at BER equal to 10-9 is
  950m, while the maximum optical distance for strong turbulence
  is 850m.

• SYNTHESIS OF PSEUDO-DYNAMIC FUNCTIONS PD-sbox-ARX-32

  S.V. Polikarpov, V. А. Prudnikov, К.Е. Rumyantsev

  2024-11-10

  Abstract ▼

  The aim of the work is to develop a method for synthesizing optimal pseudo-dynamic functions
  PD-sbox-ARX-32, 32-bit in size, in accordance with conflicting requirements for cryptographic characteristics
  of the considered structure. The methods for synthesizing classical sbox’es are considered, including
  those using evolutionary and genetic methods. The requirements for cryptographic characteristics are
  presented, both for the PD-sbox functions and for their constituent elements (classical sbox and ARX functions).
  A method for synthesizing pseudo-dynamic functions PD-sbox-ARX-32 is proposed, including two
  stages: 1) heuristic search for a structure corresponding to conflicting requirements for the resulting cryptographic
  characteristics, consumed software and hardware resources, as well as the speed of operation of the
  presented function; 2) search for optimal parameters of the main element of PD-sbox-ARX-32 – ARX functions,
  using the evolutionary method, the essence of which is to select the values of cyclic shifts in ARX functions.
  As a result, a set of four ARX functions was obtained for the pseudo-dynamic transformation of PDsbox-
  ARX-32, having the weight of linear characteristics equal to and difference characteristics equal
  to (in this case the empirical weight is ). To determine the weights of cryptographic characteristics,
  methods based on the use of SAT solvers were used in the work. The paper concludes that the selected
  structure of the 32-bit ARX function in the PD-sbox allows for a critical path (maximum number of sequential
  addition operations modulo ) that is four times smaller than that of the 8-iteration 32-bit
  Alzette-like structure, with a twofold increase in the number of operations and comparable maximum values
  of the weights of the difference and linear characteristics. A similar result is obtained when comparing
  the 32-bit ARX function with the 8-iteration 32-bit transformation from the Speck32 block cryptographic
  algorithm. The proposed method for synthesizing the parameters of the 32-bit ARX function allows for
  minimizing the number of assembler instructions spent on cyclic shift operations when implemented on
  low-resource 8-bit microcontrollers AVR (for example ATmega328P).

• EVALUATION OF THE FUNCTIONAL ELEMENTS INFLUENCE ON THE PARAMETERS OF THE QKD SYSTEM BASED ON B92 PROTOCOL

  К.Е. Rumyantsev, P.D. Mironova, H.H. Shakir

  2022-11-01

  Abstract ▼

  The influence of the parameters of functional elements on the energy, time and probabilistic
  characteristics of the quantum key distribution system (QKD) based on the B92 protocol is studied.
  The dependences of the probability of writing correct and erroneous bits into a raw quantum
  key sequence are plotted for various lengths of a fiber-optic communication line (FOCL) and the
  use of various lasers (EML-laser; DFB-laser; VCSEL-laser and FP-laser) and photodetector
  modules (id201; id210; id220; id230). Thus, changes in the probability of writing a correct bit into
  a raw quantum key sequence are much more significant than changes in the probability of writing
  an erroneous bit (50.9 times versus 3.3 times with FWHM=80 pm and a change in the length of
  the FOCL from 10 to 100 km). This is due to the fact that with an increase in the length of the
  FOCL, the probability of the absence of registration at the receiving station of photons or dark
  current pulses (DCP) sharply increases. Numerical material indicates a direct proportional dependence
  of the probability of writing an erroneous bit on the frequency of generation of noise
  pulses of single-photon avalanche photodiodes (SAPD). So, with an increase in the frequency of
  occurrence of DCP by 60 times (from 100 to 6000 Hz), the probability of recording an erroneous
  bit also increases by 60 times (for example, with a FOCL length of 100 km – 6.39 versus 383.3).
  It has been established that the root-mean-square deviation of the photon delay time is directly proportional to the length of the FOCL and the width of the laser spectrum. With a spectrum width
  of FWHM=10 pm and an increase in the FOCL length from 10 to 100 km (by a factor of 10), the
  standard deviation of the photon delay time also increases by a factor of 10 (from 4.16 to 41.6 ps).
  To achieve the best performance of the QKD system as a whole, it is advisable to use a laser with
  a minimum width of the radiation spectrum, for example, an EML-laser. However, EML-lasers are
  considered the most complex and expensive of all the considered types of lasers, so the use of
  EML-lasers significantly increases the cost of the entire QKD system.

• RANDOM ERROR OF PULSE DURATION MEASUREMENT WITH OSCILLATIONS AT THE TOP BY MULTI-THRESHOLD DURATION METERS

  D.V. Belyaev, D.E. Gubarev, К. Е. Rumyantsev

  2021-12-24

  Abstract ▼

  In systems for automatic measurement of the duration of video pulses, various devices for amplifying
  and shaping pulses of a normalized level are used, the duration of which is equal to the duration
  of the input signals. A rough measurement of the duration of video pulses can be made with onethreshold
  meters. More accurate are multi-threshold and floating-threshold meters. Pulse duration
  meters have found wide application in electronic warfare equipment, in measuring technology. The
  variation in the shape of electrical signals does not allow the use of a single measurement method,
  which is the best for all shapes, therefore, the search for technical solutions that satisfy the conflicting
  requirements continues: a wide range of durations and duty cycles. The aim of this work is to
  carry out a mathematical analysis of the random error in measuring the pulse duration with oscillations
  at the top by multi-threshold duration meters. In the course of the work, the results of a numerical
  experiment were obtained to measure the duration of a pulse with oscillations at the top using
  multi-threshold duration meters. And also a comparison was made of four multi-threshold duration
  meters for the investigated pulse shape. The calculation results are presented for a signal dynamic
  range of 60 dB and an amplitude quantization step of 3dB and 12 dB.

• COMPUTATIONALLY EFFICIENT METHOD FOR DETERMINING THE AVERAGE LINEAR PROPERTIES OF PSEUDO-DYNAMIC SUBSTITUTIONS

  S.V. Polikarpov, V.A. Prudnikov, K.E. Rumyantsev

  2021-01-19

  Abstract ▼

  Pseudo-dynamic substitutions PD-sbox can become an effective replacement for fixed substitutions
  in pseudo-random functions, since they have the positive properties of both fixed substitutions
  (low consumption of computational resources) and dynamic substitutions (which can radically complicate
  the application of statistical cryptanalysis methods). The problem of active implementation of
  pseudo-dynamic substitutions is, inter alia, the absence of a computationally efficient method for
  determining the averaged linear properties for the entire set of equivalent substitutions generated
  using PD-sbox, while in most cases, only the determination of the maximum values of the prevalence
  (bias) bias (α, β) from the ideal value 1/2. To solve this problem, an original method is proposed,
  which consists in the fact that the maximum dominance values are calculated only for relatively small
  fixed substitutions included in the PD-sbox, and the resulting maximum dominance values are obtained
  by iterative calculation using a logical-probabilistic expression for the Exclusive OR operation
  -NO (XNOR). The effect of using the proposed method is a dramatic reduction in computational
  operations and, accordingly, the possibility of determining on a typical personal computer the maximum
  values of the prevalence bias (α, β) for 16-element PD-sboxes consisting of 8-bit fixed substitutions
  (which is unattainable when using a trivial method).

• PROBABILISTIC CHARACTERISTICS OF THE THRESHOLD ALGORITHM FOR DETECTING SYNCHRONIZING PULSES IN THE QUANTUM KEY DISTRIBUTION SYSTEM BASED ON INFORMATION FROM AN ADJACENT PAIR OF TIME SEGMENTS

  K. E. Rumyantsev, Y. K. Mironov, P.D. Mironova

  2020-11-22

  Abstract ▼

  Quantum key distribution systems (QKD) provide increased security of transmitted information.
  For the stable operation of the QKD system, accurate synchronization of user stations is
  required with minimal time costs. An algorithm for detecting a sync signal with a threshold test is
  proposed. It is assumed that the sync pulse is simultaneously in two adjacent time segments. The
  probability of detecting a pair of time segments where a sync pulse is present is determined by the
  probability of exceeding the threshold level by the total number of signal and noise pulses recorded
  in two adjacent segments. The purpose of the research is aimed at a comparative analysis of the
  threshold level and probabilistic characteristics of synchronization equipment during threshold
  testing of each pair of time segments within a time frame, obtained when orienting on the Gauss
  and Poisson model for the number of photons and dark current pulses (DCP) received during the
  time segment analysis. The probabilistic characteristics of the detection algorithm for sync signals
  are studied in a quantum key distribution system based on a comparison of the number of photons
  from an adjacent pair of time segments with a threshold level. The application of the approximation
  of the statistical properties of the processes at the output of the photodetector by the Poisson
  law and the normal distribution is analyzed. The influence of the Poisson and Gaussian models on
  the choice of the threshold level and the calculation of the synchronization efficiency during the
  threshold testing of each pair of time segments within the time frame are estimated, obtained by
  orientation on the Gauss and Poisson models for the number of photons and DCP received during
  the analysis of the time segment. It was established that the choice of the threshold level based on
  the normal distribution gives an underestimated value. The approximation of the statistics of photons
  and pulses of dark current by a normal law provides a threshold level lower than the required
  one. Moreover, the difference grows with stricter requirements for the probability of false positives.
  The obtained probabilistic properties of the sync signal detection algorithm based on the
  analysis of the sum of counts from an adjacent pair of segments with a threshold level allow us to
  formulate recommendations for choosing an approximation of the signal statistics: for express
  calculations of probabilistic characteristics, it is advisable to use the Gaussian model; if a higher
  analysis accuracy is required, it is recommended to use the Poisson model.

• GENERATION OF COHERENT OPTICAL RADIATION MODULATED BY A QUADRATURE PHASE-SHIFT KEYED RADIO SIGNAL

  А. S. Mamitov , К.Е. Rumyantsev

  207-220

  2025-12-30

  Abstract ▼

  The use of broadband optical amplification, wave division multiplexing, dispersion compensation of optical radiation, and differential phase-shift keying enables data transmission at rates of up to 40 Gbit/s. Prospects for further increasing transmission rates to 100 Gbit/s are associated with the use of multilevel modulation formats for radio signals on multiple subcarrier frequencies, modulation of the radiation from a single optical quantum generator by radio signals on multiple subcarriers, balanced homodyne detection of coherent optical radiation, and digital signal processing. Symbol-based transmission via quadrature phase-shift keying (QPSK) provides high data rates. Prior studies have substantiated the use of a single-sideband coherent optical radiation generation algorithm with subcarrier QPSK modulation. Due to hardware instabilities, amplitude and phase errors may arise, leading to quadrature imbalance. These inaccuracies introduce additional errors during demodulation of the received signal, which can significantly degrade reception interference immunity. The aim of this study is to analyze the process of generating single-sideband optical radiation modulated by a QPSK radio signal on a subcarrier frequency using two parallel Mach–Zehnder interferometers. A distinguishing feature of the proposed approach is that the derived mathematical relationships make it possible to subsequently assess the impact of amplitude and phase errors in quadrature signal generation (quadrature imbalance) on reception quality.

• MODEL OF KEY SEQUENCE GENERATION IN A COHERENT DUAL-BAND OPTICAL SYSTEM WITH PHASE-SHIFT KEYED RADIO SIGNAL MODULATION

  К. Y. Rumyantsev , D.А. Tsytsorin

  2026-02-27

  Abstract ▼

  Coherent optical communication using quadrature phase-shift keying (QPSK) provides high-speed data transmission using in-phase and quadrature (IQ) modulation formats over long distances. A quadrature optical modulator with two Mach-Zehnder interferometers in a two-way configuration with simultaneous phase shift in its arms significantly improves the technical characteristics and ensures the electromagnetic compatibility of digital signal transmission paths. The two-cycle configuration of an optical modulator is the basis for high-speed and noise-resistant data transmission. The research results prove that, after certain corrections to the known coherent optical transmission structures, the system can be used for key distribution. The structure of a coherent two-band optical key sequence formation system is presented. The model for generating optical radiation with modulation by a phase-shifted radio signal is based on a quadrature optical modulator with two parallel Mach-Zehnder interferometers with constant bias voltages on all control electrode arms. Key sequence formation is implemented by modulating the in-phase and quadrature components of radio signals at the subcarrier frequency. A set of two amplitude multiplication coefficients for each bit is specified by the electronic encoding device. The coefficients represent the signals that modulate the amplitude of the in-phase and quadrature components of the subcarrier frequency, respectively. The optical radiation generated at the modulator output provides key distribution (setting the values of zero "0" and one "1" bits in the binary number system) according to a protocol with four phase states in the rectangular and diagonal bases. A module for controlling the encoding of the in-phase and quadrature components of a radio signal at a subcarrier frequency is proposed. The use of quadrature phase shift keying (QPSK) provides noise immunity to external influences at high data transfer rates

• FORMATION OF PARAMETERS OF INFORMATION SOURCES FOR NEURO-LINGUISTIC TEXT IDENTIFICATION

  К.Y. Rumyantsev , V. V. Kotenko , L.К. Khadzhieva

  173-188

  2026-07-07

  Abstract ▼

  This paper explores a method of neurolinguistic text identification aimed at analyzing and verifying information sources, including texts generated by artificial intelligence systems. Three versions of the information states of the text of Luo Guanzhong's Romance of the Three Kingdoms are analyzed: the original text and the text generated by the Gemini and GPT artificial intelligence systems. The study aims to formulate and substantiate parameters for use as identification factors in the generated text, as well as to create 3D images of neurolinguistic textual identification of information sources. The specialized software package "Neurolinguistic Text Identification Analyzer" is used, processing text data based on horizontal and vertical scanning of neurolinguistic information frames. As a result, information spectra, quantitative characteristics (information capacity, entropy, redundancy), and 3D neurolinguistic information images of neurolinguistic frames of textual information of the Chinese work are formed. A comparison of the identity levels of neurolinguistic 3D informational images of the textual information source and neurolinguistic information frames shows that the highest level of identity is observed when comparing the texts of neurolinguistic information frames with the original text, while the lowest level of identity is observed when comparing the original text with the text generated using neural networks. The obtained results demonstrate significant differences between the parameters of the neurolinguistic information frames of the original text and the parameters of the text generated by neural networks, both in terms of quantitative text characteristics and the characteristics of the neurolinguistic 3D informational images. It was found that the neurolinguistic 3D informational images of texts generated by neural networks have a smoother visual representation structure and an excellent color distribution compared to the neurolinguistic 3D images of the original text. The practical significance of this study lies in the application of an approach that allows for the identification of generated text and the verification of information sources. The obtained results open up prospects for further work and the possibility of creating programs capable of detecting the presence of text generation

• EVALUATION OF THE CHARACTERISTICS OF A TWO-STAGE SYNCHRONIZATION ALGORITHM BASED ON THE SELECTION OF AN ADJACENT PAIR OF SEGMENTS WITH THE MAXIMUM TOTAL COUNT IN THE QKD SYSTEM

  К. Y. Rumyantsev, Y.К. Mironov, P.D. Mironova

  2024-08-12

  Abstract ▼

  A two-stage synchronization algorithm is proposed based on the selection of an adjacent pair of
  segments with the maximum total count in the QKD system. The algorithm is based on a well–known approach
  to reducing the time of entering into synchronism - the analysis of adjacent pairs of time segments.
  A distinctive feature of the proposed algorithm is to ensure that the probability of successful search and
  testing is not worse than the required level. It should be noted that due to the testing stage, erroneous
  decisions made at the search stage are rejected, which minimizes the probability of false synchronization
  due to the registration of noise pulses. At the search stage, the equipment sequentially registers the total
  counts from all adjacent pairs of segments. Next, a pair of segments with the maximum total count is selected,
  and the count in one of the pairs of segments reliably exceeds the values of the counts from all other
  pairs of segments, and the equipment proceeds to the testing stage. Testing consists of polling the
  photodetector during the gating pulse to re-register the count. In case of positive testing, the process of
  «rough» estimation of the moment of reception of the sync pulse is considered successfully completed,
  otherwise the equipment returns to the search in the next frame. Note that the maximum allowable number
  of frames and tests correspond to the search and testing stages, respectively. Analytical expressions are
  obtained for calculating the time and probabilistic characteristics of the search and testing stages of the
  proposed detection algorithm based on the selection of an adjacent pair of segments with the maximum
  total count, including for calculating the allowable number of frames and tests while ensuring the required probabilities of successful search and testing, respectively. It has been found that with an increase in the
  average number of photons in the sync pulse, the average number of frames and tests, as well as the average
  time of successful search and testing, decrease significantly. For example, when the average number
  of photons in a sync pulse increases by 5 times, the average number of tests for successful testing and the
  average time for successful testing decrease by 1.5 times, and the permissible number of tests by 5 times.