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

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.

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.

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.

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.

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 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.