Vestnik of Volga State University of Technology. Series «Radio Engineering and Infocommunication Systems»

Introduction. The field of radio photonics has advanced rapidly, enabling the development of photonic analog-to-digital converters (PADCs) with distinct advantages over traditional electronic ADCs. PADCs offer new opportunities for designing digital radio receivers with enhanced performance. This paper evaluates the potential of PADCs in radio receivers through modeling in specialized software. The study addresses the following objectives: (1) selecting an optimal PADC circuit for a radio receiver, (2) developing a model of a radio receiver incorporating a PADC, (3) fine-tuning the PADC elements’ parameters, (4) validating the model using a test signal mixed with noise, and (5) assessing the performance characteristics of the receiver with a PADC. Modeling. The model of the PADC’s optical circuit was developed using OptiSystem software, which provides an extensive library of optical and electronic components with adjustable parameters. This setup enables a detailed analysis of how individual elements affect PADC performance. OptiSystem also integrates with MATLAB for additional computational capabilities. Established models of circuit components, such as a mode-locked laser with specifications aligned with real-world systems, were incorporated during model development and testing. Results. The resulting model of a digital radio receiver with an all-photonic ADC exhibits the following characteristics: 1) Bit depth – 8 bits, scalable by adding channels; 2) Sampling frequency – Adjustable via pulse repetition rate, reaching up to 100 GHz in the model; 3) Noise considerations – Accounts for intrinsic noise from optical and electronic components. Simulations revealed that a 4 dB increase in insertion loss at the Mach-Zehnder modulator (MZM) could cause signal degradation, which can be mitigated by adjusting the comparator’s response level. Notably, maximizing the photodiode’s thermal noise did not alter the output signal. Conclusion. The proposed digital radio receiver with a PADC achieves a sensitivity of -110 dBm in the absence of external interference. The structure supports signal processing up to 50 GHz without requiring additional filtering or signal transfer components. This design demonstrates the potential of PADCs to enhance the dynamic range and performance of radio receivers.

Introduction. This paper proposes a method and algorithm for the joint reception and positioning of moving objects based on the principles of information field theory. A signal model for systems operating within the information field is developed, along with a synthesized multimarkov-polygaussian model of such signals. An algorithm for estimating the parameters of signals in these systems is presented, and the effectiveness of the proposed solutions is evaluated. The aim is to enhance the functionality of communication systems with mobile objects by developing methods and algorithms for the joint reception of signals based on information field theory. Methods.  Information field theory and multi-markov-polygaussian processing algorithms are applied to enable positioning functionality within existing communication systems. Findings. Using these methods and models, the paper develops a signal model for systems operating in the information field, synthesizes a probabilistic signal model based on the multimarkov-polygaussian approach, designs an algorithm for parameter estimation, and assesses the efficiency of the proposed solutions. The practical significance. The developed methods and algorithms reduce errors in determining the coordinates and velocities of passive objects, and can be implemented in communication systems with mobile objects to significantly enhance their functionality.

Introduction. The relevance of employing OSINT (Open Source Intelligence) and CTI (Cyber Threat Intelligence) in the evolving landscape of cybersecurity is increasingly recognized. This is particularly evident in the growing number of targeted attacks and the limitations of traditional security measures in detecting them. There is a pressing need to address the key challenges associated with integrating OSINT and CTI data into corporate information security systems, as well as the automation of intelligence data collection and analysis processes. Objective. This study aims to explore the applicability of various OSINT tools for identifying vulnerabilities in information systems, using the MITRE ATT&CK framework and focusing on techniques from the "Reconnaissance" tactic. Methodology. The research methodology includes a comparative analysis of modern OSINT and CTI tools, a review of approaches to processing and interpreting threat intelligence data, and practical testing of selected MITRE ATT&CK tactics and sub-techniques. The study evaluates five sub-techniques under the "Reconnaissance" tactic: IP block scanning (T1595.001), wordlist scanning (T1595.003), DNS/passive DNS analysis (T1596.001), use of WHOIS data (T1596.002), and database scanning (T1596.005). Tools such as Nmap, Dirb, dig, WHOIS, and Shodan were utilized to implement these techniques. Results. Active IP block scanning and DNS analysis proved effective in identifying critical IT infrastructure vulnerabilities, including open ports and insecure service configurations. The use of Dirb and Shodan enabled the discovery of hidden vulnerabilities in web applications and internet-connected devices. WHOIS data analysis revealed risks associated with the public availability of domain ownership information, which can be exploited in phishing attacks and social engineering schemes. The findings highlight the importance of integrating OSINT with the MITRE ATT&CK framework for the systematic analysis of threats and vulnerabilities. The proposed approach enables organizations not only to detect potential threats but also to implement preventive measures such as WHOIS data monitoring, regular scanning of internet-exposed assets, and DNS record analysis. This contributes to enhanced cyber resilience and reduced risk of successful cyberattacks. Conclusion. The application of OSINT tools within the MITRE ATT&CK framework provides cybersecurity professionals with an effective means for proactively identifying threats and vulnerabilities. The results of this study can inform cybersecurity practices, including the development of new defense tools and the enhancement of existing threat monitoring systems. Future research will focus on the quantitative assessment of this approach’s effectiveness to better evaluate its impact on organizational cybersecurity.

Introduction. Reactive multilayer foils undergoing self-propagating high-temperature synthesis (SHS) consist of alternating layers of two or more materials capable of participating in an exothermic reaction. These foils are typically fabricated using thin-film deposition techniques such as magnetron sputtering. Activation is achieved through external stimuli–electrical, thermal, laser, or mechanical–resulting in a rapid release of heat. Peak reaction temperatures can reach 1500 °C, and the energy released may be as high as 1200 J/g. The combustion front can propagate at speeds of 8–10 m/s. Due to the broad range of industrial applications for reactive multilayer foils, there is a need for a reliable method to monitor the critical parameters of the foil–both post-fabrication and during the optimization of fabrication processes. This study aims at developing and validating a comprehensive monitoring method for the SHS reaction in multilayer thin-film structures, allowing for simultaneous assessment of reaction characteristics using a single experiment on a single sample. The following objectives were posed in the study: to analyze existing monitoring methods and propose new or improved approaches suitable for integration into a unified methodology; to conduct experimental validation using sample foils tailored to the testing techniques employed within the comprehensive method; to develop and substantiate a unified monitoring approach based on experimental data, emphasizing the behavior of SHS in thin-film structures. Results. A calorimetric setup using copper plates and platinum sensing elements effectively measured the energy released during the SHS reaction. Thermal equilibrium was reached within 1–1.5 minutes. Preheating the system to +35 °C (above room temperature) accelerated cooling but had no effect on the final thermal equilibrium state. A method was proposed for determining the SHS reaction activation energy by gradually increasing the voltage across a capacitor, followed by direct contact between the capacitor electrodes and the foil surface. The activation energy was found to be independent of both pulse duration (capacitor capacitance) and amplitude (applied voltage). For example, activation occurred with a 300 μF capacitor at 12 V (yielding 23.8 mJ), as well as with a 1000 μF capacitor at 6.9 V, corresponding to the same energy level of 23.8 mJ. The propagation velocity of the SHS reaction front was successfully measured using two optical sensors (phototransistors). With a l = 20 mm distance between sensors, the required sensor response time and system measurement accuracy (error ≤ 0.1 ms) were established. The selected phototransistors demonstrated a response time of 15 μs.