The active use of aerial objects creates a need for passive detection methods. This paper presents an experimental study of an automated acoustic hardware and software system based on the five-channel microphone array. Field tests were conducted in open terrain under conditions of background noise and wind. It is shown that the system provides stable determination of angular coordinates at distances up to 60 m, while a decrease in stability is observed at 80 m. The achieved accuracy of angular coordinate determination is 2–5°. It has been established that at short distances, the GPS error can cause significant angular uncertainty that exceeds the error of the acoustic system, limiting its use as a reference standard. The obtained results confirm the feasibility of application of the acoustic methods and identify the directions for the further development of acoustic localization systems.
This study presents the development of a modified electrophysiological model of a human epicardial cardiomyocyte, achieved by taking into account the temperature effects on the kinetics and conductance of ion channels using parameter-specific Q10 coefficients. Based on the modified model, a temperature sensitivity analysis was performed to identify the key ionic mechanisms that regulate thermal adaptation of action potential duration (APD). The simulation was performed in the temperature range of 25–45 °C using a hybrid approach that combines local and global sensitivity analyses. Local analysis was performed by calculating elasticity coefficients to evaluate the impact of individual temperature parameters on APD. Global analysis was carried out using the Morris method of elementary effects to rank parameters by their influence and to identify non-linear interactions. The results demonstrate that the rapid delayed rectifier potassium current (IKr) plays a predominant role in the modulation of APD. It accounts for approximately 85% of the total APD shortening when the temperature rises to 42 °C, where APD decreases by 22.03% (from 270.91 ms to 211.24 ms). Under deep hypothermia (25 °C), a 52.47% prolongation of the action potential (AP) and a 169% increase in the repolarization phase duration were observed. Furthermore, the study reveals that at moderate hypothermia (30 °C), non-linear interactions between various ion channels become a decisive factor. A significant contribution of the sodium-calcium exchanger (NCX) and the late sodium current (INaL) was demonstrated at lower temperatures, confirming the temperature dependence of these interactions. These findings underscore the critical role of the human Ether-à-go-go-Related Gene (hERG) in the thermal adaptation of the ventricular myocardium and provide a computational framework for investigating the mechanisms of thermo-induced arrhythmias.
This paper considers the task of improving road traffic safety through the development of a bidirectional warning system for road users. The proposed system provides mutual information interaction between a vehicle driver and a pedestrian or animal located near the roadway. The system generates warning signals for both parties based on the spatial position of the detected object and the level of potential danger. The developed system is based on a multisensor approach using sensors of different physical principles and a two-factor detection algorithm, which reduces the number of false activations. The operating area is divided into warning and critical zones with corresponding modes of visual and acoustic notification. To validate the effectiveness of the proposed model, simulation modeling was performed in the MATLAB environment, which made it possible to evaluate the dependence of the correct detection probability on sensor reliability. The obtained results demonstrate an improvement in system reliability when using the multisensor approach and confirm the feasibility of applying the developed solution in intelligent road infrastructure.
This research presents the design, multi-threaded software implementation, and empirical evaluation of an active, electromyography (EMG)-driven upper-limb orthosis utilizing a distributed master-slave embedded control architecture. Engineered specifically to address the clinical challenges of severe upper-limb paresis—such as those resulting from brachial plexus trauma—the system bypasses traditional localized muscle control by acquiring voluntary surface EMG signals from the sternocleidomastoid (SCM) neck muscle, utilizing it as a stable proxy for motion intent. To ensure hard real-time deterministic execution and high-fidelity signal processing, the system is physically and logically decoupled into three operational layers. A dedicated analog front-end (AD8232) and an STM32F407 microcontroller handle localized biosignal conditioning and digitization. A Jetson Nano single-board computer operates as the supervisory node, executing a strictly governed finite state machine (FSM) to perform digital filtering, feature extraction, and motion classification. Finally, an ESP32 microcontroller paired with a BTS7960 high-current H-bridge manages real-time brushed DC motor actuation. Communication across these distinct hardware layers is achieved wirelessly via a TCP/IP protocol over Wi-Fi, eliminating cumbersome physical tethers and establishing a foundation for advanced Internet of Things (IoT) integration. Software execution relies on a multi-threaded, mutex-protected environment capable of achieving an average sample-to-result latency of 6.02 milliseconds. Real-time joint angle feedback is continuously provided by an AS5048A absolute magnetic encoder via an SPI interface, ensuring kinematic safety and rigid adherence to predefined anatomical limits. Experimental results validate the system's capacity for safe, highly responsive operation, demonstrating that complex classification algorithms and wireless distributed topologies can successfully meet the rigorous latency requirements of wearable rehabilitation robotics, though future iterations may necessitate the integration of brushless actuators to mitigate static friction and low-speed operational limitations.
This paper explores a methodological approach to modernizing the higher mathematics curriculum for engineering students, with a specific focus on the needs of “G5 Electronics, electronic communications, instrumentation and radio engineering” specialty. The study addresses the growing challenge posed by the "black box" paradigm, in which students rely on automated online calculators and artificial intelligence tools without comprehending the underlying mathematical logic or algorithmic structures. To counteract this trend, the authors propose integrating GNU Octave, an open-source computational environment, as a primary tool to bridge the gap between abstract theory and professional engineering practice. The article demonstrates the practical implementation of GNU Octave across three critical mathematical domains: Integral Calculus, emphasizing symbolic and numerical methods for signal processing applications; Multivariable Functions, focusing on 3D visualization techniques (using meshgrid and surf) for modeling spatial physical fields and potential distributions; Differential Equations, utilizing numerical solvers like ode45 to simulate transient processes in electronic circuits. The results suggest that transitioning from simplified automated tools to script-based computational modeling fosters a conscious mastery of mathematical concepts. This approach ensures that future engineers develop the analytical and programming competencies needed for complex system optimization and professional modeling in modern electronics.
The article shows that the physical conditions limiting the acoustic power radiated by location devices are the levels of permissible strengths of their elements. The purpose of this paper is to analyze each of these limitations in detail. It is determined by the method of systematic analysis that these strengths include mechanical, electrical and cavitation. Each of them is associated with its own physical field, which takes part in the formation of a given acoustic power of a location device. As a result, the physical reasons for the appearance of electrical, mechanical and cavitation strengths are established. Analytical expressions between the levels of the given strengths and the powers of acoustic radiation are determined.
In modern technical systems, clustering serves as a key procedure for structuring, analyzing, and interpreting large volumes of data, which in turn enhances decision-making efficiency and the optimization of system processes. This study presents a comparative analysis of the main groups of clustering methods and proposes a novel approach based on the powerful mathematical framework of cardinal numbers. The theoretical foundations for constructing cardinal number vectors are revealed, positioning them as a mathematical tool for data representation in clustering tasks. The proposed approach defines object distances within a selected orthogonal basis using the calculated cardinalities of abstract set sequences represented as vectors of cardinal numbers. The study explores the formation of these vectors and the computation of corresponding similarity metrics, followed by the generation of a distance matrix. A practical example illustrates the calculation of distances between three functions and a reference function based on their respective cardinal number vectors. It is demonstrated that altering the basis or projections according to the technical problem allows for the formation of different clusters, reflecting the flexibility and adaptability of the proposed method. The calculations are formalized, straightforward, and easily algorithmized, which enables the implementation of dynamic clustering. This approach holds significant promise for use in intelligent data analysis systems and information processing in electronic devices.
Pulsed gas-discharge guns are promising tools in modern electron beam processing technologies. These devices operate on the basis of a high-voltage glow discharge (HVGD) and are capable of generating high-power electron beams. The article provides an overview of existing gun designs, examines the physical processes of plasma formation and beam focusing, and describes the influence of design features on operational stability and thermal load. Special attention is paid to the influence of the working gas type on beam characteristics, the technological capabilities of the device, and prospects for improving discharge current control. The principles of constructing automated beam parameter control schemes that ensure stability in the pulsed mode are considered. Examples of practical applications of guns based on HVGD are provided.
Метою даної роботи є аналіз можливості використання та ефективності нового запропонованого графічного методу оцінки наявності різниці між здоровим і хворим органом слуху біологічного об’єкта під час реабілітації від ототоксичного впливу. Вказаний метод призначений для забезпечення більшої швидкості аналізу, підвищення його якості та можливості його застосування всім медичним персоналом – як лікарським, так і сестринським. Матеріал і методи. Під час підготовки даних було проведено 41 експеримент. Всього було виконано 3936 вимірювань, по 96 для кожного експерименту. Кожне вимірювання проводилося на одному вусі морської свинки шляхом використання отоакустичної емісії на частоті продукту спотворення. Із зазначених 41 експерименту 40 були проведені на піддослідних групах з різним впливом медикаментів (як ототоксичний, так і лікувальний), а один проводився як референтний – для демонстрації нормального стану органу слуху. У кожному експерименті вимірювання були розподілені між 6 діапазонами частот (2 кГц, 4 кГц, 6 кГц, 8 кГц, 10 кГц, 12 кГц) – по 16 вимірювань у кожному. Далі було розраховано середнє значення сигналу отоакустичної емісії та стандартну помилку в кожній смузі для кожного експерименту. Отримані значення були використані в представленому методі для пошуку відмінностей між ними. Пізніше був реалізований статистичний аналіз для перевірки надійності методу. При статистичному аналізі було враховано нормальність розподілу результатів у групах і в залежності від цього використано параметричний або непараметричний тест. Надійність зазначених методів перевіряли також шляхом використання критерію Соколова. Результати. Імплементація запропонованого методу показала, що для кожного діапазону частот результати були розділені на дві великі групи – нормальна група (містить експеримент №1 у своєму складі) і відмінна група. Відмінності між двома групами наступні – нормальна група має вищі середні значення, менші стандартні помилки експериментів у ній і результати менш кучно розподілені на графіку. Надійність запропонованого методу перевіряли за допомогою трьох різних тестів – наявність статистично значущих відмінностей між середніми значеннями експериментів у нормальній групі та групі із відмінностями, наявність статистично значущих відмінностей між даними експерименту № 1 та кожного експерименту в групі з відмінностями та кореляція результатів методу із результатами використання критерію Соколова. Випробування підтвердили надійність запропонованого методу і показали, що він навіть має переваги перед уже використовуваними методами – будь то більша чутливість або простота його реалізації. Висновок: тестування нового методу показало його надійність за результатами проведених серій тестів для кожного діапазону частот. Крім простоти реалізації та збільшення швидкості аналізу результатів, запропонований метод також має більш високу чутливість, ніж деякі вже існуючі методи аналізу результатів аналізу стану органу слуху в біологічному об'єкті.
This paper presents the possibility of employing an ionic polymer–metal composite (IPMC) actuator for coplanar waveguide fed antenna reconfiguration. Proposed antenna structure integrates defected ground structure (DGS) into the feeding line, which performs role of the band-reject filters, enhancing selectivity and shaping the frequency response. The IPMC strip acts as an electromechanical tuning element and lifts a separate substrate above the primary radiator. Such replacements alter the electromagnetic field distribution and lead to the operating frequency shift, offering a low-power alternative to conventional methods. With only 5V of bias voltage, operating frequency tuning rage is about 130%, from 2.61 GHz to 6.11 GHz, without bringing additional losses. The results confirm the feasibility of IPMC actuators for frequency tuning applications.
The application of the theory of moments to distributed generation systems for the construction of a reducing and predicting polynomial of the time distribution of entropy changes in time at the base interval is proposed. It is shown that in order to improve the accuracy of forecasting, it is necessary to take into account the fractal nature of energy consumption processes and use Rényi entropy in calculations. By taking into account the fractal nature of the energy consumption process and the use of Rényi entropy in calculations, an increase in prediction accuracy by 11% is achieved, resulting in the prediction of the time distribution of Shannon's entropy for power consumption with an error not exceeding 23%.
To calculate the parameters of the Marx generator, such as the voltage at the generator output, the values of the circuit elements and, if necessary, the number of generator cascades, an electrical model was created with a load represented as a negative corona discharge in a cylindrical electrode system at atmospheric pressure. When creating the model, its input parameters were defined, the influence of the current-voltage characteristic of the corona discharge on the generator operation was investigated, and the impact of deionization processes on the output parameters of the model (output voltage on the generator, nominal values of circuit elements, etc.) was analyzed. For more effective modeling of processes in the Marx generator, its general equivalent circuit was divided into two parts, in which the charging and discharging processes of the Marx generator stages were studied separately. The model will be useful in the design of relatively simple systems based on a Marx generator that use a corona discharge, such as ionisers, electric filters, surface modification devices, etc.
This paper explores the integration of Scilab software into the higher mathematics curriculum for engineering students, focusing on enhancing the understanding and application of function analysis. It addresses the necessity of equipping future engineers with skills in both theoretical mathematics and computational tools. The study provides practical examples, such as plotting functions, finding asymptotes, and interpolation techniques, demonstrating how Scilab can aid in solving complex mathematical problems. The authors argue for a balanced educational approach, combining traditional mathematical methods with the effective use of software to enhance learning outcomes in engineering education.
The paper considers and analyzes the method of measuring the noise characteristics of electronic circuits and devices based on data collection by a digital oscilloscope with a built-in Fourier transform. The measurement process methodology and its analysis are demonstrated when determining the noise characteristics of industrial resistors. This includes, in particular, thermal (white) noise, which is the predominant type of resistor noise. The work includes an overview of the noise properties of resistors and existing measurement methods, as well as an understanding of the theory of such measurements. To determine the sources of noise in industrial resistors, a real-time fast Fourier transform (FFT) of the signal was run on an oscilloscope. Thermal (white) noise spectra were determined using the FFT tool using a total number of 212 points.. However, it is difficult to make any recommendations as to which setup should be used for a particular resistor type or technology, as for most setups the noise level is unknown and only a few measurement results are available. The ratio of the average value of the power spectral density (PSD) of thermal noise in the frequency range of measurements to its calculated theoretical value based on the ohmic rating of the measuring coal industrial resistors was estimated.
Виробництво акумуляторних батарей у світі стрімко зростає, що пов’язано із розвитком електротранспорту та альтернативної енергетики. Акумуляторні батареї мають свій обмежений ресурс, а доступної технології утилізації акумуляторних батарей на даний час немає. Явище дисбалансу дуже негативно впливає на ресурс акумуляторних батарей, проте застосування систем балансування протидіє цьому ефекту, тим самим збільшуючи загальний ресурс акумуляторної батареї. Покращення систем балансування може позитивно вплинути на ресурс акумуляторних батарей, та відтермінувати час їх утилізації У статті представлено розробку DC-DC перетворювача для систем активного балансування акумуляторних батарей у форматі студентських змагань. Авторами була висунута попередня гіпотеза, вибору оптимальної топології DC-DC перетворювача для використання в певному активному балансирі. Для підтвердження цієї гіпотези, була сформована задача для студентських змагань, а саме побудова ізольованого DC-DC перетворювача, що міг би працювати в даному прототипі активного балансира. Активний балансир розрахований на балансування акумуляторної батареї, що складається з трьох послідовно підключених комірок. Учасникам було надано набір компонентів, а також додатковий фінансовий фонд, для придбання додаткових компонентів необхідних для практичної реалізації DC-DC перетворювача. Змагання проводились в режимі обмеженого часу, і на виконання завдання було виділено 48 годин. Критерії оцінювання були чітко виділенні, а головним критерієм було працездатність DC-DC перетворювача. З п’яти команд, три впорались із завданням, та зайняли призові місця. На основі студентських змагань було проаналізовано різні топології ізольованих DC-DC перетворювачів, зокрема SEPIC, Push-Pull та DAB, показано принцип їх роботи, розглянуто переваги та недоліки. Особливу увагу приділено топології DAB, яка була визнана найкращим варіантом для використання в даному активному балансирі завдяки можливості роботи в широкому діапазоні вхідних-вихідних напруг, високій ефективності та двонаправленості. В статті наведено результати вимірювань, проведених на прототипі DAB перетворювача, та обговорюються складнощі його реалізації. Таким чином, результати роботи сприяють підвищенню ефективності активних систем балансування акумуляторних батарей, подовженню терміну їх служби та розвитку технічних навичок студентів.
The article presents the development of a DC-DC converter for active battery balancing systems in the format of student competition. Active balancing, which ensures stable energy transfer between battery cells, is critically important for optimizing their operation and extending their service life. Various topologies of DC-DC converters, in particular SEPIC, Push-Pull and DAB, are analyzed, their advantages and disadvantages are shown. The results of the work contribute to increasing the efficiency of battery balancing systems, extending their service life and developing students’ technical skills.
Modeling of a glow discharge in a cylindrical coaxial system with dielectric ends of electrodes in the hydrodynamic drift-diffusion approximation was performed. Model parameters: outer cathode diameter 10 and 13 mm, anode diameter 2 mm, voltage 2800 V, gas temperature 300 K. pd ~ 1 Pa∙m, which corresponds to the left side of the minimum area of the Paschen curve for discharge ignition. Reactions of ionization of atoms by electron impact, generation and quenching of metastable atoms, elastic collision of electrons with atoms and elastic collision of ions, resonant recharging of ions, Penning ionization, as well as secondary ion-electron emission of the cathode were taken into account. The distribution of potential and concentration of charged particles in the interelectrode space, the density of ion and electron currents were calculated within the framework of a self-consistent problem, and the current-voltage characteristics for two modes of discharge - plasma and plasma-free - were presented. The effect of pd on the parameters and discharge mode is determined. The obtained results can be used in plasma technologies for modification of the internal surfaces of metal, hollow, long parts with a small cross-sectional size, that is, in conditions close to those complicated by the occurrence of a discharge.
The interaction between metal nanoparticles and substrates under plasmonic resonance conditions plays a crucial role in various optical applications. In this study, we research the impact of substrate material on the optical response of silver nanoparticles under surface plasmon resonance conditions. Using theoretical modeling based on the quasi-static dipole approximation, we explore how the dielectric constant of the substrate affects the extinction cross-section spectra of silver nanoparticles as a function of nanoparticle size and distance from the substrate surface. The calculation results show significant shifts in the extinction peak and enhancements in the extinction cross-section values when considering different substrate materials, including cellulose, indium tin oxide and silver. It was found that substrates with higher dielectric constants induce larger shifts in the extinction peak towards longer wavelengths and lead to increased extinction cross-section values at the operating wavelength. Furthermore, it was found that the orientation of the external electric field relative to the substrate surface influences the magnitude of these shifts. The results of the study show that while changing the size of the nanoparticles has minimal effect on the position of the extinction peak, increasing nanoparticle size significantly enhances the maximum extinction cross-section values. Additionally, varying the distance between the nanoparticles and the substrate surface causes shifts in the extinction spectra, with larger shifts observed for substrates with higher dielectric constants. These findings provide valuable insights into the design and optimization of plasmonic structures for various optoelectronic applications. By understanding the nanoparticle-substrate interactions and their optical properties, our theoretical study aids in the prediction of optical responses and the development of tailored optical structures for enhanced productivity of their usage. Overall, this study highlights the importance of substrate material selection and nanoparticle-substrate interactions in engineering plasmonic systems for advanced optical applications, paving the way for the design of efficient and optimized optoelectronic devices and sensors.
This paper provides a comprehensive review of four primary models used to represent Helmholtz resonators in sound-absorbing structures. The purpose of the article is to analyze these models in the context of their application, accuracy, and suitability for different types of acoustic problems. The review focuses on: the simple harmonic oscillator model, which provides a basic yet effective approach for estimating resonance frequencies; the wave equation model, which is well-suited for complex geometries and wave propagation phenomena; the electrical analogy model, used to represent resonators in systems with multiple interacting elements; and the Finite Element Method (FEM), offering high precision for detailed simulations of complex acoustic systems. For each model, typical calculation problems are discussed to highlight their practical applications, along with examples from existing research. Additionally, the article provides recommendations for further development of these models. This review serves as a foundation for selecting appropriate modeling methods for various acoustic design challenges and offers guidance for future research in this field.
The incidence of diabetic retinopathy (DR), a complication of diabetes leading to severe vision impairment and potential blindness, has surged worldwide in recent years. This condition is considered one of the leading causes of vision loss. To improve diagnostic accuracy for DR and reduce the burden on healthcare professionals, artificial intelligence (AI) methods are increasingly implemented in medical institutions. AI-based models, in particular, are integrating more algorithms to enhance the performance of existing neural network architectures that are commercially used for DR detection. However, these neural network models still exhibit limitations, such as the need for high computational power and lower accuracy in detecting early DR stages. To overcome these challenges, developing more advanced machine learning models for precise DR detection and classification of DR stages is essential, as it would aid ophthalmologists in making accurate diagnoses. This article reviews current research on the use of deep learning in diagnosing and classifying DR and related diseases, as well as the challenges ophthalmologists face in detecting this condition and potential solutions for early-stage DR detection. This review provides information on modern approaches to DR detection using deep learning applications and discusses the issues and limitations in this area.
