No 4 (2024)
Telecommunication and radio engineering
Method of Ensuring Semantic Interoperability in the Sensor Data Processing
Abstract
Introduction. Currently, the volume of sensor data from heterogeneous sources is significantly increasing. This leads to the need of improving the efficiency of sensor data management by addressing semantic interoperability. The aim of the work was to reduce the errors in interpreting sensor data by comparing and evaluating the similarity between descriptions of the parameters of measurement objects and the concepts used to describe measured quantities and units, utilizing semantic annotations. Methods. The research employs an ontological approach as its primary method. Since most sensor data pertains to the measurement of object parameters, the proposed method involves comparing and assessing the similarity of parameter descriptions based on an ontology of measured quantities, units of measurement, and sensor types. To achieve this, a semantic interoperability system is proposed for the Industrial Internet of Things (IIoT) and sensor systems. Additionally, a sequence diagram is developed to facilitate the exchange of requests and informational messages between IoT devices, the IIoT system, and the semantic interoperability system. Results. The resulting model, developed using expert knowledge, can support import substitution by enabling compatibility with new types of sensors.



Enhancing antenna array isolation using passive radiators
Abstract
Introduction. Improving antenna isolation is crucial for ensuring intra-facility electromagnetic compatibility (EMC), especially in environments with densely packed antennas. Despite extensive research in this area, the quest for effective isolation enhancement methods remains ongoing. This study explores an approach that utilizes passive radiators to mitigate antenna coupling. The aim of the work is to develop techniques for improving isolation, thereby addressing EMC challenges in compact radio-electronic systems. The evaluation of isolation coefficients was conducted in two stages. First, a preliminary analysis and optimization were performed using a matrix model of the antenna array. In the second stage, numerical methods were applied using existing electromagnetic simulation software to refine the results. Results. The findings demonstrate that optimizing the positions and parameters of passive radiators can enhance isolation across various antenna systems by 8 to 50 dB. Additionally, the study reveals that isolation improvements of 20–25 dB can be achieved over significantly wider frequency bands. Expanding the frequency range with high isolation is also possible by increasing the number of compensating passive elements.



Method for fixing a vibrating acoustic emitter in a bone conduction hearing aid to minimize sound ener-gy loss
Abstract
Introduction. This paper addresses the pressing challenge of developing effective bone conduction hearing aids. Existing methods for securing vibrating acoustic emitters in such devices have several drawbacks, including unstable connections, sound energy loss, and limited options for individual adjustments. The aim of this study is to design a fixation device for a vibrating acoustic emitter in a bone conduction hearing aid and examine how the pressure connection parameters in the "sound emitter – ear implant" system affect the quality of the transmitted sound. Technical Features of the Fixation Device. A novel fixation device has been developed, incorporating a titanium implant and a polymer ring. This design allows for adjustable pressure between the emitter and the bone, ensuring a secure and stable connection. Additionally, a personalized approach to abutment design—utilizing a parametric computer model created in a three-dimensional design system (such as Compass3D©)—optimizes prosthesis geometry for individual patients. Results. The amplitude-frequency response (AFR) and phase-frequency response (PFR) were measured for two prototype designs: a screw implant with spherical abutments and a screw implant with a vibration-conducting platform. Experimental analysis demonstrated that the proposed innovative fixation method eliminates AFR dips at mid frequencies, which is crucial for speech perception, smooths AFR and PFR curves, resulting in a more natural and balanced sound, reduces AFR nonlinearity by more than 6 dB (17%). Conclusion. The proposed fixation device exhibits high efficiency and significant potential for application in bone conduction hearing aids. Future research will focus on assessing the long-term stability of the system and developing customized solutions tailored to individual patients' needs.



Linear Incoherent Antenna Arrays Focused in the Near Radiated Field Zone
Abstract
Introduction. Antenna systems designed for operation in the near-radiated field zone,
using the principle of in-phase addition of electromagnetic waves emitted by individual sections of an aperture at the focal point, are gaining increasing attention. From the perspective of conveniently forming the required amplitude-phase distributions of partial currents, antenna arrays are commonly employed as radiating systems. An alternative approach to achieving focused spatial distributions of
electromagnetic fields involves the synchronous addition of energy from short pulses with durations on the order of a nanosecond. In this case, synchronicity at the focal point is ensured by controlling the emission timing of individual pulses based on the distances between each radiator in the antenna array and the focal point. In this initial exploration of the properties of incoherent focused antenna arrays, we limit our analysis to the behavior of the radio pulse envelope. The aim of the article is to is to
examine the main properties of incoherent focused radiation formed by the synchronous addition of individual pulses at the focal point. The research methods are grounded in established principles of electrodynamics and radio wave propagation, implemented through mathematical models simulating the propagation of a set of partial pulses in the near-radiated field zone, while accounting for the
focusing effect. The simulation results indicate that effective incoherent focusing can be achieved for focal lengths approximately equal to the linear size of the antenna array. As the focal point distance increases, the disparity in distances between the outer and central emitters to the focal point diminishes. This leads to near-synchronous pulse emission by individual emitters, ultimately reducing the focusing effect. The maximum transverse deviation of the focal point from the normal axis to the center of a linear antenna array is determined to be half the array's linear size. When the focal point shifts transversely from the normal axis, the size of the focused area increases. Conclusion. By appropriately controlling the emission timing, it is possible to steer the focal point within the bounds of the aperture size. Additionally, optimizing the coordinates of individual emitters in an incoherent antenna array, transitioning to flat or volumetric antenna arrays, and exploring arrays with complex
spatial geometries hold significant promise for achieving desired spatio-temporal distributions. These advancements will enhance the potential applications of antenna arrays focused in the near-radiated field zone for various radio engineering purposes.



Uplink subscriber channel analysis for non-terrestrial communication system
Abstract
Introduction. In the era of digital progress, the demand for telecommunication services continues to grow, and their applications are expanding. However, many people still lack access to these services due to limited terrestrial coverage in remote areas. Non-Terrestrial networks, which integrate terrestrial and space-based components, can provide wider coverage while alleviating the load on terrestrial infrastructure. This technology involves deploying functions similar to those of a terrestrial base station on a satellite, an approach known as a regenerative payload. A key feature of this implementation is its ability to connect unmodified user devices directly to the satellite. However, this places stringent requirements on onboard equipment. The aim of this study is to assess the feasibility of providing communication via the uplink subscriber channel in a non-terrestrial network using the latest technological components. Methods. The analysis of the subscriber uplink channel parameters is based on a standard direct conversion receiver on board a spacecraft, utilizing third-generation terrestrial network technology. Results. The analysis of the subscriber channel revealed that while communication is fundamentally possible – achieving speeds of up to 144 kbps under favorable conditions and 12.2 kbps under unfavorable conditions – high transmission rates should not be expected due to significant signal attenuation along the transmission path. To overcome data rate limitations in the future, the adoption of more advanced communication technologies and signal processing methods should be considered, along with the use of lower transmission frequencies. The analysis of contemporary technological components demonstrated that state-of-the-art equipment enables processing across the entire 70 MHz frequency band allocated by the standard. Additionally, due to the high sampling frequency of modern ADCs, it is possible to enhance the dynamic range, achieving a gain of 3.5 dB when processing in a discrete system.



Computer engineering and informatics
Study on the influence of joystick handle shape on manipulator control accuracy
Abstract
Introduction. Manipulator control is widely used in operator-driven systems, including logging, construction equipment, and aircraft. To facilitate operator input into control systems for such machinery, joysticks or sidesticks—manipulated along two or three axes – are commonly employed. The design of these joysticks can vary significantly depending on the control task at hand. The shape of joystick handles may influence tactile feedback perception, mechanical force application, and overall feedback depth between the operator and the equipment. The aim of this study is to examine how different joystick handle shapes, sizes, and gripping methods affect the accuracy and speed of operator control. Methods and materials. To objectively measure joystick handle positioning accuracy and speed, a computer-based test was developed, displaying visual feedback on a monitor. A bootstrapping approach was used to assess statistically significant differences between groups. Cluster analysis and dimensionality reduction techniques, including Principal Component Analysis (PCA) and Uniform Manifold Approximation and Projection (UMAP), were applied alongside the k-means unsupervised machine learning method to identify potential clusters in the data. Results. Cluster analysis using PCA, UMAP, and k-means did not reveal distinct groups. However, weak clustering tendencies were observed in the UMAP representation. No statistically significant differences were found in joystick positioning accuracy across different handle shapes, sizes, and gripping methods. From a speed and accuracy perspective, variations in joystick handle shape, size, and grip do not significantly impact operator performance, provided the joystick handle maintains an ergonomic design. In tasks where speed is prioritized over precision – while maintaining acceptable accuracy – full-size joysticks with a palm grip are recommended.



Randomness testing of pseudorandom number genera-tors for semi-natural simulation stands in asynchro-nous electronic systems
Abstract
Introduction. To accurately reproduce test conditions in semi-natural simulation stands, it is essential to generate signals with various probability distributions over power and time. Pseudorandom number generators (PRNGs) are commonly used for this purpose. Given their practical application in semi-natural simulation stands, evaluating the randomness of their generated sequences is crucial. The NIST statistical test suite is widely used to assess the randomness of number sequences. It determines the statistical similarity between a generated pseudorandom sequence and a theoretically perfect random sequence. This study aims at analyzing the performance of binary sequences generated by PRNGs—defined by GOST R ISO 28640-2012—in NIST randomness tests using a developed simulation software. Methods and Tools. This research involves developing software tools to simulate PRNGs based on GOST R ISO 28640-2012 using the following methods: five-parameter method; Tausworthe method; combined Tausworthe method; Mersenne Twister method. To assess the randomness of these generators, their output sequences were subjected to 16 NIST statistical tests. Each test evaluated finite-length sequences, calculating statistics and comparing them with reference statistics of a perfectly random sequence. Results. The study found that the Mersenne Twister method generated the sequence most closely resembling a true random series, passing 14 out of 16 NIST tests. Furthermore, it was observed that modifying the input parameters of certain PRNG methods could enhance their ability to pass specific tests, thereby improving the overall "randomness" of the generated sequences. Conclusion. This research developed and implemented software tools for modeling PRNGs based on GOST R ISO 28640-2012 and evaluated their randomness using the NIST test suite. The results indicate that the Mersenne Twister method is the most suitable PRNG for semi-natural simulation stands in asynchronous electronic systems. Additionally, further improvements to PRNG algorithms are necessary to increase their statistical test pass rates.



Instrument engineering
Analysis of correlating processing’s influence on the evaluation of informative low-amplitude components in z-electrocardiosignals
Abstract
Introduction. The development of devices capable of effectively analyzing electrocardiosignals (ECS) is a relevant and significant task, particularly in enhancing their functionality. Currently, there are no single-channel devices that can evaluate ventricular late potentials (VLPs)—low-amplitude components with predictive value. The aim of this study is to assess the feasibility of detecting VLPs in ECS recorded using a single lead. Materials and methods. For this study, Z-lead ECS signals were selected. A total of 271 signals were analyzed using two approaches: the standard method for detecting VLPs (Simson’s method) and a modified version of this method adapted for Z-lead ECS (the proposed algorithm). To improve analysis accuracy, smoothing techniques and an additional correlation-based processing algorithm were applied. Results. The standard approach detected VLPs in 46 cases, whereas the proposed algorithm identified 80 cases. This may indicate a potential advantage of the proposed algorithm, particularly since the analyzed signals exhibited characteristics associated with myocardial infarction. The probability of a correct decision when testing the algorithm exceeded 73%. Conclusion. The proposed algorithm effectively detects VLPs in Z-lead ECS. These findings may contribute to the development of single-channel ECS analyzers.



The novelties in the field of engineering and technologies. Reviews. Conferences. Important dates
Implementation of acceleration programs "VolgaTECH" in the Volga State Technological University
Abstract
The results of the implementation of the acceleration programs "VolgaTECH 2.0" and "VolgaTECH 3.0" at the Volga Region State Technological University for 2023–2024 are presented.


