# 4 2024

• V. A. Sudakov, A. V. Timoshenko, K. S. Sokolov, S. V. Matseevich
  Algorithm for supporting decision-making by the operator of a space monitoring radar station in an emergency situation based on a hybrid function
• Abstract
  • Purpose. Statement of the problem: modern space monitoring radar stations are complex technical human-machine systems. In various situations, including abnormal ones, the radar operator is obliged to transmit information to higher management bodies. The impact of new destructive factors of various nature on the operator leads to an increase in the probability of issuing false information to higher management bodies, which is largely due to the human factor and is unacceptable. The objective of the work is to develop the mathematical foundations of a new toolkit for a decision support system for an MCP radar operator in an abnormal situation in order to reduce the probability of transmitting false information to higher management bodies. Result: the work proposes a methodological, mathematical and algorithmic toolkit that allows for a multi-criteria analysis of an abnormal situation under the conditions of the destructive influence of the real cosmic background on the radar characteristics. It is shown that decision support systems created on the basis of this toolkit will be able to take into account a greater number of factors than an individual operator. Practical relevance: the use of a hybrid preference function in the toolkit allows space monitoring to be performed in a mode close to real time, which reduces the operator's workload by providing him with advisory information on the current state of the radar. In the future, it will be possible to build a hierarchy of hybrid preference functions to eliminate errors caused by the human factor in the interaction of operators.
• Key words
  • decision support, multicriteria analysis, preference function, algorithm
• Reference
  • Sudakov V. A., Timoshenko A. V., Sokolov K. S., Matseevich S. V. Algorithm for supporting decision-making by the operator of a space monitoring radar station in an emergency situation based on a hybrid function. Systems of Control, Communication and Security, 2024, no. 4, pp. 145-157. DOI: 10.24411/2410-9916-2024-4-145-157 (in Russian).

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• A. F. Zaytsev
  An approach to transforming a model of multigraph knowledge base of the subject area into a relational database model
• Abstract
  • Purpose. The problem of building modern software-intelligent and expert systems requires solving a variety of different tasks. At present, the complexity of building such systems lies in the fact that the known ‘classical’ models and approaches to the construction of expert systems do not agree well with the relational model of data representation, which makes it impossible to effectively use modern industrial database management systems for the organization and representation of knowledge, as well as their use in various information systems. The purpose of the work is to transform the proposed multigraph knowledge base model of the subject area into a relational database model to improve the efficiency of information processing using modern automated control systems. Methods The approach allowing the transformation and storage of knowledge of subject areas in tabular representation and relational databases are proposed. The approach reflects the principles and rules for performing the decomposition of the knowledge base model with a multigraph, representation of the knowledge multigraph using algorithmic data structures (hash-tables), storing the knowledge multigraph in the tabular form of the database using the selected symbolic format (JSON), as well as performing the reverse transformation and aggregation of the multigraph vertex lists from relational to non-relational form. The following generals’ scientific methods were used: analysis, decomposition, synthesis, modeling, formalization, structurization, algorithmization, generalization, comparison, description, computational experiment, as well as set theory and graph theory, on the basis of which the used model of knowledge representation was built. Computers and software tools – database management systems, programming languages, and their interpreters – were used as research materials. Novelty. The elements of novelty are a new mathematical model of representation of knowledge of the subject area on the basis of the multigraph, as well as the proposed approach to the transformation of the knowledge base model on the basis of the multigraph into a relational database model. Results. A comparative analysis is carried out, and the main definitions, features, and differences between data and knowledge are given. The process of building the multigraph knowledge base model designed to solve computational problems in the selected subject area is described. Problems of interaction with the multigraph knowledge base are identified and described. An approach to solving the identified issues was developed and applied, which consists of transforming the multigraph knowledge base model of the subject area into a relational database model. Types, formats, and structures of knowledge representation and the peculiarities of their application in the selected management system are considered. Practical relevance. The software implementation of the knowledge base in the selected programming language is shown. Listings with code fragments in programming languages for interaction with the base, as well as examples of knowledge representation and processing, are given. The implementation of the proposed approach makes it possible to organize and store knowledge in the form of databases, which allows for more efficient knowledge processing and management using a relational model. In addition, knowledge management is performed using existing, proven, and productive industrial-level database management systems. The use of the proposed approach opens new opportunities for the design and implementation of modern software-intelligent and expert systems.
• Key words
  • knowledge representation problem, knowledge bases, databases, dynamical systems modeling, expert systems, knowledge multigraph, expert information, intelligent systems, programming and automation, software systems development
• Reference
  • Zaytsev A. F. An approach to transforming a model of multigraph knowledge base of the subject area into a relational database model. Systems of Control, Communication and Security, 2024, no. 4, pp. 158-178. DOI: 10.24411/2410-9916-2024-4-158-178 (in Russian).

• M. T. Nguyen
  Innovative approaches to the design of sparse wire-grid antennas: development of algorithms and evaluation of their effectiveness
• Abstract
  • Problem Statement: reducing the mass and size of space antennas is a critical challenge in the design and development of space communication systems. Lightweight and compact antennas can be efficiently integrated into satellites and spacecraft, enhancing efficiency and flexibility in the development and operation of communication systems. The wire grid (WG) approach, based on the Method of Moments (MoM), is widely used to approximate conductive surfaces of various types of antennas. This approach reduces resource costs compared to other methods while maintaining the required antenna characteristics. Given the growing demand for reducing the mass and size of antennas, significant attention is being paid to the development of sparse antennas. Previous studies have proposed the Optimal Current Grid Approximation (OCGA) approach and its modifications for creating sparse antennas. However, limitations in existing approximations have been identified, affecting the performance of the antennas. Therefore, there is a need to modernize these approaches to enhance their effectiveness in creating optimized sparse structures. Objective: the aim of this study is to modernize the OCGA algorithms to overcome the limitations of existing methods and improve the characteristics of sparse antennas created using these approaches. Methods: the study applies the modernized algorithms to reflector and conical horn antennas. Simulation results are compared with those of previous approaches and measurements of industrial antennas. Novelty: advanced algorithms have been introduced that eliminate free wires, maintain grid continuity, and optimize sparse structures. These algorithms offer higher accuracy and efficiency compared to previous ones. Results: the modernized algorithms have demonstrated significant reductions in antenna mass, memory requirements, and modeling time, as well as improved characteristics of sparse antennas compared to the original structures. Practical relevance: this research provides antenna manufacturers with the ability to choose the appropriate algorithms for designing sparse antenna and their optimal values for specific applications, contributing to antenna optimization and cost reduction. Potential further applications of the results include the development of sparse antennas using the considered approaches with the modernized algorithms and 3D printing technology and comparing measurement results with modeling.
• Key words
  • wire grid, method of moments, sparse antennas, optimal current grid approximation, conical horn antenna, reflector antenna
• Reference
  • Nguyen M. T. Innovative approaches to the design of sparse wire-grid antennas: development of algorithms and evaluation of their effectiveness. Systems of Control, Communication and Security, 2024, no. 4, pp. 1-47. DOI: 10.24412/2410-9916-2024-4-001-047 (in Russian).

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• Z. P. Kupriyanov, P. V. Kupriyanov, S. A. Petrov, E. V. Tereshkin, S. A. Timofeev
  Researching the uplink signal of the subscriber terminals Starlink
• Abstract
  • Problem Statement: The article considers various aspects of the application of subscriber terminals "Starlink" with an emphasis on the possibility of their detection and direction finding by means of radio monitoring. A brief analysis of available sources of information on the topic of the publication is made. The research of our own experiment on the study of the signature of the uplink signal of the subscriber terminal «Starlink» by a domestic hardware complex are given. Calculated and experimental estimates of the detection range are given. Objective: the aim of this research is to assess the possibility of detecting the location of Starlink subscriber terminals by means of radio monitoring along the side lobes of the uplink antenna directivity diagram in the Ku-band. Methods: in-situ experimental methods for studying the levels and radio structure of the Starlink terminal are changed. Novelty: the presented full-scale experimental studies of such a high-tech electronic device, which is the Starlink subscriber terminal using a domestic radio monitoring device, are being carried out for the first time in our country. Foreign publications on this topic are also not known to the authors. Result: as a result of the experiment, the fundamental possibility of observing the uplink signal of Starlink user terminals along the side lobes of the antenna pattern at significant ranges was shown. Practical relevance: the possibility of creating domestic specialized complexes for radio monitoring of signals from Starlink subscriber terminals, including determining their location, is being disclosed.
• Key words
  • subscriber terminals "Starlink", Ku-band uplink signal, side lobes of the antenna pattern, radio monitoring
• Reference
  • Kupriyanov Z. P., Kupriyanov P. V., Petrov S. A., Tereshkin E. V., Timofeev S. A. Researching the uplink signal of the subscriber terminals Starlink. Systems of Control, Communication and Security, 2024, no. 4, pp. 287-304. DOI: 10.24412/2410-9916-2024-4-287-304 (in Russian).

• A. A. Boyko, H. I. Maihoub, I. A. Mosolov
  Countering UAVs Mathematical Models Overview
• Abstract
  • Problem Statement: Currently, the task of countering small-sized (i.e. nano-, micro-, mini- and short-range) unmanned aerial vehicles at critical military and civilian facilities is of particular relevance. The systems that ensure the implementation of this task are technically complex. The construction of such systems requires a high degree of accuracy, which, in turn, leads to great difficulties, since systems of this type must combine communication, reconnaissance, control, electronic warfare and fire destruction systems. Today, such systems are built empirically, without taking this feature into account, often even without individual subsystems, and therefore cannot guarantee the implementation of the task assigned to them in extreme conditions, when a significant number of small-sized unmanned aerial vehicles are used to inflict maximum damage on a critical facility. To improve the efficiency of such systems, a developed scientific and methodological apparatus for its assessment is required. This apparatus should be based on a model of the process of countering unmanned aerial vehicles at a critical facility, reproducing the specified feature. Aim of the paper: identifying the ability of known mathematical models of the process of counteracting unmanned aerial vehicles to take into account the mutual influence of the processes of reconnaissance, communication, control, fire damage and electronic warfare. Used Methods: systems analysis. Novelty: consideration of the process of countering small-sized unmanned aerial vehicles at critical facilities in the context of an antagonistic conflict between two high-tech organizational and technical systems, each of which implements a cycle of applying the processes of reconnaissance, communication, control, fire damage and electronic warfare to achieve its goals. Result: generalization of the known models of the process of countering unmanned aerial vehicles made it possible to identify the need to integrate existing detailed simulation models of this process, taking into account only the processes of reconnaissance and fire damage, with an analytical combat model that takes into account the set of necessary processes, but is not able to reproduce them in detail. Practical relevance: The result of the work is necessary for the development of a scientific and methodological apparatus for assessing the effectiveness of counteraction to small-sized unmanned aerial vehicles at a critical facility.
• Key words
  • unmanned aerial vehicle, critical asset, effectiveness, countermeasures, combat simulation and analytical modeling
• Reference
  • Boyko A. A., Maihoub H. I., Mosolov I. A. Countering UAVs Mathematical Models Overview. Systems of Control, Communication and Security, 2024, no. 4, pp. 48-71. DOI: 10.24411/2410-9916-2024-4-48-71 (in Russian).

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• A. A. Boyko, M. Yu. Bykov, S. S. Kusсhev, M. A. Peregudov
  Authentication in Cellular Networks: Evolution, Review of Security Methods and New Vulnerabilities
• Abstract
  • Task Statement: The vast majority of attacks on cellular networks begin with the exploitation of vulnerabilities in their authentication procedures, allowing attackers to intercept, view, and modify user information. Numerous studies focus on the security of cellular network standards such as AMPS, NMT, GSM, UMTS, LTE, and 5G. However, despite in-depth theoretical research, these studies are fragmented and do not enable a comprehensive view of the development of authentication procedures in cellular networks from the first to the current generation, as well as the methods for exploiting these procedures' vulnerabilities (the so-called IMSI catchers). The aim of this work is to analyze the evolution of authentication procedures in cellular networks to identify patterns in the origins of these vulnerabilities for forecasting the further development of interception devices and creating effective countermeasures. Methods used: systems analysis method, method for generating cyber-attacks on telecommunications equipment. Novelty: based on the systematization of existing knowledge using the method of generating cyber-attacks on telecommunications equipment, new, previously unexplored potential vulnerabilities in authentication procedures of various generations of cellular networks have been identified. Result: the need to improve the authentication procedure in cellular networks, taking into account identified vulnerabilities, has been identified, revealing a contradiction in practice: the demand for measures that eliminate vulnerabilities in the authentication procedure and the lack of such measures. Practical significance: the result of this work serves as a motivating factor to improve the scientific-methodological apparatus for assessing the effectiveness of countering existing vulnerabilities and establishes the foundation for developing effective means of protecting mobile device information, which will minimize the risks associated with cyber-attacks and ensure the protection of critical information during storage, transmission, and processing.
• Key words
  • mobile communication security, false base stations, IMSI-catcher, StingRay, GSM, UMTS, LTE, 5G
• Reference
  • Boyko A. A., Bykov M. Yu., Kusсhev S. S., Peregudov M. A. Authentication in Cellular Networks: Evolution, Review of Security Methods and New Vulnerabilities. Systems of Control, Communication and Security, 2024, no. 4, pp. 95-144. DOI: 10.24411/2410-9916-2024-4-95-144 (in Russian).

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• R. V. Maximov, A. P. Telenga
  The Concept of Countering the Identification of Corporate Information Systems Metastructures at the Level of Percolation Clusters in Cyberspace
• Abstract
  • Problem statement: corporate information systems (CIS) metastructures are secondary structures that are formed under the influence of various processes and can be used to analyze and uncover the processes of CIS functioning in cyberspace using cyber intelligence (CI). The problem of countering the identification of information systems metastructures at the level of cyberspace percolation clusters can be formulated as a multi-criteria optimization problem using the metric of percolation adaptability as a masking optimality criterion. Purpose. The goal of this work is to modify a graph representing an information system by adding new vertices and edges to its single-mode projections in such a way as to increase its percolation adaptability, i.e., reduce the percolation centrality of vertices for each projection, reduce the similarity between the original and modified graph, and at the same time maximize the size of the connected component by adding a minimum number of vertices. Methods used: the solution of the problem of counteracting the CIS metastructures identification at the level of the cyberspace percolation clusters is based on the developed methodology of counteracting identification, including algorithms of masking and performance evaluation by random walk for the proposed model of the CIS at the level of the cyberspace percolation clusters, allowing the method of optimization DIRECT to determine the optimal parameters of masking. Novelty. The novelty element of the presented solution is the use of the percolation centrality index and the introduction of a new set of actions and links between them to determine the importance of graph vertices and the subsequent formation of a modified graph taking into account these criteria, which allows us to take into account not only the topological information of the graph, but also its percolation structure for the generation of new vertex and edge information. Results: the use of the presented solution to counteract the identification of CIS metastructures at the level of the cyberspace percolation clusters allows to increase its percolation adaptability, i.e. to reduce the percolation centrality of vertices for each projection, to reduce the similarity between the original and modified graph, and at the same time to maximize the size of the connected component by adding a minimum number of vertices. The simulation conducted to evaluate the performance of masking by random walks for a set of graphs with 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 vertices showed a 40% reduction in the probability of traversing the vertices of the original graph in the masked graph (i.e., uncovering the original CIS structure) in 100 attempts for different criterion importance ratios. Practical relevance. The presented solution could be realized in the form of mathematical support of deception network information objects. This will allow to create more adaptive and effective mechanisms to counteract the identification of CIS metastructures in cyberspace, increasing the complexity of analyzing and detecting potential threats by an attacker.
• Key words
  • metastructure, corporate information systems, masking, percolation, percolation adaptability, cyberspace, perplexity, t-SNE
• Reference
  • Maximov R. V., Telenga A. P. The Concept of Countering the Identification of Corporate Information Systems Metastructures at the Level of Percolation Clusters in Cyberspace. Systems of Control, Communication and Security, 2024, no. 4, pp. 179-222. DOI: 10.24411/2410-9916-2024-4-179-222 (in Russian).

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• I. E. Afonin, S. I. Makarenko, R. L. Mikhailov, N. A. Kupriyanov, A. A. Potapov
  Aerospace Attack Means by Leading Foreign Countries. Part 2. Submarine-Launched Ballistic Missile
• Abstract
  • Relevance. The increase in geopolitical tensions observed since the start of 2022 has increased the likelihood of military conflict. The use of aerospace attack means (ASAM), such as ballistic missiles, has become a hallmark of modern warfare. In some instances, a conventional conflict may escalate into a nuclear war, with submarine-launched ballistic missiles (SLBMs) being used for both preventive and counter-nuclear missile strikes. This research aims of the work to create descriptive models of ASAM of leading foreign nations (LFN), in particular, the formation of descriptions of SLBMs. The model is based solely on open-source information. The results and their novelty. The generalized tactical and technical characteristics of typical LFN SLBMs are an element of novelty of the work. Practical significance. The descriptive model, which is presented in the work. The results of this study will contribute to the existing body of knowledge regarding SLBMs, providing valuable insights into the complexities of these systems and their potential impact on global security. The descriptive model of SLBMs will be useful for specialized specialists to substantiate the requirements for the tactical and technical characteristics of promising aerospace defense systems and methods of their combat use to ensure the protection of the Russian Federation.
• Key words
  • means of aerospace attack, descriptive model, submarine-launched ballistic missiles, tactical and technical characteristics, warhead, combat unit
• Reference
  • Afonin I. E., Makarenko S. I., Mikhailov R. L., Kupriyanov N. A., Potapov A. A. Aerospace Attack Means by Leading Foreign Countries. Part 2. Submarine-Launched Ballistic Missile. Systems of Control, Communication and Security, 2024, no. 4, pp. 223-286. DOI: 10.24411/2410-9916-2024-4-223-286 (in Russian).

• A. G. Loschilov, N. D. Malyutin, Chin To Thanh, G. A. Malyutin
  Reducing return loss and suppressing out-of-band oscillations in interstage connections of communication systems using non-reflective frequency-selective microwave circuits
• Abstract
  • Statement of the problem. Improving counteraction systems to communications equipment of unmanned aerial vehicles (UAVs) and other aviation equipment has become a very urgent task at present. This is, in particular, due to the fact that the power of emitted high-frequency pulses is constantly increasing (up to hundreds of megawatts). When exposed to radio frequency broadband signals, a reliable method of protection is the use of frequency-selective filters. This allows you to isolate useful components of the frequency spectrum and reflect unwanted ones. However, in this case, reflected signals can cause intermodulation interference, especially in devices with nonlinear elements. The creation of non-reflective filters allows you to solve the problem of reducing unwanted reflections. Purpose. The aim of the work is modeling and development of non-reflective band-pass filters with the following features: preservation of the properties of the frequency-selective circuit at a low level of return loss, both in the transparency band and at the cut-off frequencies with an overlap of at least 1:6, to consider the use of such filters in combination with traditional reflective filters to demonstrate the effects of reducing return loss in the cut-off frequency range and suppressing parasitic passbands with cascaded connection of nodes. Methods. Modeling and development of non-reflective band-pass filters is carried out on the basis of the basic circuit of non-reflective filters containing a section of coupled lines with loads in diagonal ports in the form of RLC circuits from identical series LC circuits shunted by resistance. When developing the NF model, the decomposition method into simpler blocks with distributed and lumped parameters was used. The development is based on numerical modeling data followed by experimental verification. Novelty. The novelty of the modeling is the presented solution to the problem of analysis based on the known parameters of the strip structure. The circuit and design are protected by patents for inventions. Their novelty is based on the features of the interaction of the lumped RLC circuit and coupled lines that form the wave process. Results. The problems of analysis and experimental study of non-reflective stripline band-pass filters are solved. The mechanism of formation of the frequency response of non-reflective filters is investigated, consisting in the transformation of the frequency dependence of the impedance of loads on lumped elements into the antipode of this characteristic using the proposed circuit and design. In this case, band-pass filters containing a distributed base element in the form of coupled lines have a single passband and return losses at the level of –10 dB at out-of-band frequencies. The paper shows the effect of using non-reflective frequency-selective circuits based on coupled striplines and RLC elements, consisting in reducing return losses and suppressing out-of-band oscillations in interstage connections in various combinations of non-reflective and reflective devices. Cascade connection options in the form of traditional filters and non-reflective filters are considered. Practical relevance. Non-reflective circuits (filters) can serve as a "trap" for reflected waves at out-of-band frequencies and be used in equipment for interstage decoupling. In this case, return losses in circuits of cascade connection of devices are reduced from a value close to 0 to –16 dB, as well as out-of-band oscillations are suppressed from –20 to –40 dB.
• Key words
  • non-reflective filters, coupled strip lines, RLC lumped circuits, cascade connection of non-reflective and reflective filters
• Reference
  • Loschilov A. G., Malyutin N. D., Chin To Thanh, Malyutin G. A. Reducing return loss and suppressing out-of-band oscillations in interstage connections of communication systems using non-reflective frequency-selective microwave circuits. Systems of Control, Communication and Security, 2024, no. 4, pp. 72-94. DOI: 10.24411/2410-9916-2024-4-72-94 (in Russian).