# Видання НТУ "ХПІ"

Постійне посилання на розділhttps://repository.kpi.kharkov.ua/handle/KhPI-Press/62886

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Документ A generalized physical principle of development of plasma channel of a high-voltage pulse spark discharge in a dielectric(Національний технічний університет "Харківський політехнічний інститут", 2024) Baranov, M. I.Goal. Development of the generalized physical principle of development of plasma channel of a high-voltage electrical pulse spark discharge in the homogeneous dielectric of the different aggregate state. Methodology. Basis of physical optics, theoretical electrical engineering, electrophysics bases of technique of high-voltage and large pulse currents, bases of high-voltage pulse technique and measuring technique. Results. Development of physical principle of development of plasma channel of an electric pulse spark discharge is executed in a homogeneous gas dielectric on the applied example of the use in calculations and experiments of the double-electrode discharge system (DEDS) with a long air interval, testing action of standard interconnect аperiodic pulse of high-voltage of temporal shape of Tₘ /Тd ≈200 μs/1990 μs of positive polarity. The generalized formula is got for the calculation of total length of l c of the real way of development of an pulse spark discharge in an air dielectric, which allowed to formulate the offered physical principle in the following kind: "The plasma channel of an pulse spark discharge in a gas dielectric spreads from one of its points to other after a way length of l c, providing the least falling on it of electric voltage of Uc". It is shown that this principle in the first approaching can be applied and to the homogeneous liquid and hard dielectrics. Comparison of the developed physical principle of distribution of plasma channel of an electrical spark discharge is executed in a dielectrical environment with fundamental Fermat physical principle (a law) for distribution of light in an optically transparent environment, which specifies on mathematical likeness and closeness on destiny of these physical principles. Calculation estimations of falling of electric voltage of Uc on total length of l c of the real zigzag way of development in the air dielectric of DEDS a "edge-plane" with the least length of its discharge interval of lmin=1,5 m is presented, that a value Uc does not exceed 9 % from the experimental level of aggressive voltage of U≈611,6 кV in this DEDS for the аperiodic pulse of voltage of Tₘ/Тd≈200 μs/1990 μs. It is set that the estimated time of td advancement of leader channel of electric pulse discharge in air DEDS (lmin=1,5 m) on its real way total length of l c≈1,53 m makes t d≈15,3 μs, and experimental duration of cut of Tdc of the indicated аperiodic impulse of voltage utilized in experiments, characterizing time of short circuit by the plasma channel of discharge of air interval in DEDS, appears equal Тdc≈t d≈17 μs. Originality. The generalized physical principle of development of plasma channel of a high-voltage electrical pulse spark discharge is first developed in the homogeneous dielectric of the different aggregate state. Practical value. Application in electrical engineering practice and high-voltage pulse technique of the offered principle of distribution in the dielectrics of plasma channel of an pulse spark discharge will allow to develop both new and to perfect the existent methods of computer design of electro-discharge processes in the gas, liquid and hard insulation of different high-voltage electrical power engineering and electrophysics devices, directed on the increase of reliability of their operation. References 25, figures 5.Документ A maximum power point tracking of a photovoltaic system connected to a three-phase grid using a variable step size perturb and observe algorithm(Національний технічний університет "Харківський політехнічний інститут", 2023) Zerzouri, Nora; Ben Si Ali, Nadia; Benalia, NadiaThe production of electricity from solar energy is necessary because of the global consumption of this energy. This article's study is based on increased energy extraction by improving maximum power point tracking (MPPT). From different MPPT techniques proposed, the perturb and observe (P&O) technique is developed because of its low implementation cost and ease of implementation. Methods. A modified variable step-size P&O MPPT algorithm is investigated which uses fuzzy logic to automatically adjust step-size to better track maximum power point, compared with the conventional fixed step-size method. The variable step P&O improves the speed and the tracking accuracy. This controller is implemented on a boost DC-DC power converter to track the maximum power point. The suggested controlled solar energy system includes a boost converter, a voltage-source inverter, and a grid filter. The control scheme of a three-phase current-controlled pulse-width modulation inverter in rotating synchronous coordinate d-q with the proposed MPPT algorithm and feed-forward compensation is studied. Results. The photovoltaic grid-connected system controller employs multi-loop control with the filter inductor current of the inverter in the inner loop to achieve a fast dynamic response and the outer loop to control bus voltage for MPPT, the modeling, and control of three phase grid connected to photovoltaic generator is implemented in the MATLAB/Simulink environment and validated by simulation results.Документ A method of protecting information in cyber-physical space(Національний технічний університет "Харківський політехнічний інститут", 2023) Dzheniuk, Nataliia; Yevseiev, Serhii; Lazurenko, Bogdan; Serkov, Oleksandr; Kasilov, OlegThe subject of the study is the processes of ensuring the reliability and security of information in cyber-physical space. The objective is to develop recommendations for the implementation of a method of information security in cyber-physical space. The development is based on the technology of ultra-wideband signals circulating in wireless communication channels. The task is to ensure the stable and reliable operation of the airborne wireless mobile communication network, which is the main component of cyberspace and its most vulnerable link to destructive influences. Methods used: methods of analytical modelling and time-position pulse coding. The following results were obtained. It is shown that in order to ensure high quality of wireless network operation, it is necessary to expand its bandwidth, which is limited by the physical resource of the radio frequency spectrum. It is proposed to overcome this contradiction by applying the technology of ultra-wideband signals, the base of which is much larger than one. In this case, the information signal is emitted without a carrier frequency simultaneously in the entire frequency band, provided that the signal level is lower than the noise level. The method of positional-time coding is used, in which each information bit is encoded by hundreds of ultra-short chip pulses arriving in a certain sequence. In such wireless communication systems, the use of autocorrelation reception of modulated ultra-wideband signals is proposed. A comparative analysis has shown that the wireless network with the best reliability and noise immunity is the one where the time separation of the reference and information signals is applied. During the first half of the bit interval, the switch closes the transmitter output directly to the ultra-wideband signal generator, forming a reference signal. In the middle of the bit interval, the switcher switches the output to one of two possible positions depending on the signal "zero" or "one", forming the information part of the signal. Conclusions. Systems with autocorrelation reception and separate transmission of reference and information signals provide a high level of structural signal concealment, as well as reliable transmission of digital information, especially in conditions of interference.Документ A novelty approach to solve an economic dispatch problem for a renewable integrated micro-grid using optimization techniques(Національний технічний університет "Харківський політехнічний інститут", 2023) Manikandan, Krishnan; Sasikumar, Sivakumar; Arulraj, RajendranThe renewable integrated microgrid has considered several distributed energy sources namely photovoltaic power plant, thermal generators, wind power plant and combined heat and power source. Economic dispatch problem is a complex operation due to large dimension of power systems. The objective function becomes non linear due to the inclusion of many constraints. Hourly demand of a commercial area is taken into consideration for performing economic dispatch and five combinations are considered to find the best optimal solution to meet the demand. The novelty of the proposed work consists of a Sparrow Search Algorithm is used to solve economic load dispatch problem to get the better convergence and accuracy in power generation with minimum cost. Purpose. Economic dispatch is performed for the renewable integrated microgrid, in order to determine the optimal output of all the distributed energy sources present in the microgrid to meet the load demand at minimum possible cost. Methods. Sparrow Search Algorithm is compared with other algorithms like Particle Swarm Optimization, Genetic Algorithm and has been proved to be more efficient than Particle Swarm Optimization, Genetic Algorithm and Conventional Lagrange method. Results. The five combinations are generation without solar power supply system and Combined Heat and Power source, generation without solar and wind power supply systems, generation including all the distributed energy sources, generation without wind power supply system and Combined Heat and Power source, generation without thermal generators. Practical value. The proposed optimization algorithm has been very supportive to determine the optimal power generation with minimal fuel to meet the large demand in commercial area.Документ Acceleration of boolean gene regulatory networks analysis using FPGA(Національний технічний університет "Харківський політехнічний інститут", 2023) Vasylchenkov, Oleg; Salnikov, Dmytro; Karaman, DmytroGene expression does not occur arbitrarily and spontaneously, it obeys certain patterns that can be expressed as a connected graph or network. The disclosure of these patterns requires a large amount of experimental research and accumulation of necessary statistical information. Then this information is subjected to mathematical processing, which involves significant computing resources and takes a lot of time. Boolean networks are often used as the basis for building mathematical models in those calculations. Recently, models based on Boolean networks have increasingly grown in size and complexity causing increased demands on traditional software solutions and computing tools. Field-programmable gate arrays (FPGAs) are a powerful and reconfigurable platform for implementing efficient and high-performance computing. The use of FPGA will significantly speed up the process of calculating sequential chains of gene states, both through the use of hardware acceleration in the calculation of logical dependencies, and through the implementation of an array of parallel computing cores, each of which can perform its own individual task. Another solution that can significantly simplify the work of researchers of gene regulation networks is the creation of a universal computing architecture that will allow dynamic reconfiguration of its internal structure when the task or logical dependencies for the current Boolean network change. Such a solution will relieve the researcher of the need to perform the entire set of actions for the technological preparation of a new FPGA configuration, from making changes to the HDL code that describes the network to uploading the updated configuration to the hardware accelerator. The article discusses how to use FPGA for the implementation and modeling of arbitrary Boolean networks, describes the concept of a universal reconfigurable architecture of a logical dependency calculating core for an arbitrary Boolean network and proposes a practical implementation of such a calculating core for modeling gene regulation networks.Документ Acceleration of exit to steady-state mode when modeling semiconductor converters(Національний технічний університет "Харківський політехнічний інститут", 2023) Yagup, V. G.; Yagup, K. V.The purpose of the article is to develop a method and algorithm for the accelerated calculation of steady states of thyristor converters using computer models of converters based on the use of the theory of difference equations in the form of recurrent linear relationships for state variables on the boundaries of the converter periods. Methodology. The article is devoted to the solution of the problem of reducing the cost of computer time to achieve the steady state of the thyristor converter. For this, it is proposed to use difference equations, for which the values of the state variables at the limits of the periods of the converter's operation are taken as variables. These values are accumulated during the initial periods of the transient process of the converter, after which the coefficients of the difference equations are calculated, and the following limit values of the state variables are found using the defined difference equations. A program in the algorithmic language of the MATLAB system is presented, which implements the proposed method and algorithm compatible with the visual model of the converter. Results. The theoretical foundations of the proposed method and the area of its applicability are substantiated. Recommendations are presented for determining the number of periods of the flow process that must be calculated for further implementation of the method. An algorithm for forming matrix relations for determining the coefficients of difference equations with respect to the values of state variables at the boundaries of periods is shown. Matrix equations are given that allow calculating the parameters of the steady state. All stages of the algorithm are illustrated with numerical examples. Originality. The method rationally combines all the advantages of visual modeling based on the numerical integration of equations using the method of state variables for the periods of operation of the converter with the analytical solution of the recurrence relations obtained on this basis for the values of state variables at the boundaries of adjacent periods. Practical value. The proposed method makes it possible to reduce by several orders of magnitude the computer time spent on calculating the parameters of the steady-state mode of the converter and, at the same time, to significantly improve the accuracy of these calculations. The practical application of the method is very effective in research and design of thyristor converters of electrical energy parameters.Документ Accounting the emissions of engine fuel vapors in the criteria-based assessment of the ecological safety level of power plants with reciprocating ice exploitation process(Національний технічний університет "Харківський політехнічний інститут", 2022) Kondratenko, Olexandr Mykolayovych; Andronov, Volodymyr Anatoliyovych; Polishchuk, Tetiana Ruslanivna; Kasionkina, Natalia Dmytrivna; Krasnov, Viacheslav AnatoliyovychThis study proposed the approach and method on its basis for carrying out of the calculated assessment of the values of the comprehensive fuel and environmental criterion of Prof. I. Parsadanov as the indicator of the ecological safety level of the exploitation process of power plants with diesel reciprocating internal combustion engine, considering the mass hourly emissions of engine fuel vapor caused by the phenomena of large and small breathing of reservoirs. The purpose of the study is to develop the method for taking into account the parameters of pollutant emissions into the environment, such as motor fuel vapors due to the phenomena of large and small breathing of the power plant fuel tanks, as an independent factor of ecological safety. The calculated assessment according to the proposed method is carried out considering the properties of engine fuel, degree of a fuel tank filling, features of model of the engine operation, daily difference of atmospheric air temperature and settings of the respiratory valve of the tank. It is found that considering the emission of engine fuel vapors caused by the phenomenon of small breathing has almost no effect on the level of environmental safety, but for the option of taking into account the effect of the phenomenon of large breathing, such an effect is significant. The scientific novelty of the obtained results is that for the first time a method for considering the emission of engine fuel vapors caused by large and small breathing of fuel tanks of reciprocating internal combustion engines in complex criteria-based assessment of ecological safety. The practical value of the obtained results is that they are suitable for quantitative and qualitative assessment of the studied effects and development on this basis of technical solutions and organizational measures to reduce or eliminate them by developing appropriate environmental protection technology with actuators on a methodological basis of environmental safety management system, including the use of other steady standardized testing cycles as models of engine operation.Документ Acousto-optical receiver of an obstruction passive radar system(Національний технічний університет "Харківський політехнічний інститут", 2023) Rustamov, Asad; Kerimov, Yashar; Mammedov, Ahmed; Binnatov, Mehman; Katekhliyev, VusalThe subject of research in the article is the passive radar system of a warship. The purpose of the work was to review the characteristics use of the acousto-optical receiver in the new passive radar system of the warship, to investigate the peculiarities of acoustooptic effect and the relevant synthesis of methods and tools for measuring the photodetector photoelectric characteristics and, in addition, to investigate the energy-and-geometric parameters of laser radiation Justification. It is shown that the transition, impulse and frequency characteristics are taken as the main means to determine the operating and technical parameters of the acousto-optical delay line. It is not possible to unambiguously extrapolate these characteristics to the known models of the characteristics of the acousto-optic radar receiver created on AODL. Research results. In the context of this postulate, mathematical models of the main characteristics of AODL were developed. On the basis of the synchronous compensation pulse obstacles applied to the passive radar acousto-optic receiver on military ships, the full compensation of the obstacles is determined for the effective reception of signals from the acousto-optic receiver. In radar stations (radar), the main attention is focused on the statistical properties of the useful signal and passive obstacles, the speed (frequency) of the signal passing through the passive obstacle and the space-time differences. The recommendations. These features are recommended to be used only in special cases where the target is outside the reflectors for informational duration, amplitude and differences between passive obstacles, obstacle silencing and signal separation. Conclusion. Applying the full attenuation of the band filter and synphase barrier organizers, whose frequency characteristics do not depend on the tuning frequency, it is possible to provide full compensation of obstacles during the effective reception of signals by the acousto-optic receiver in the passive radar system of warships based on the proposed method for high resistance to obstacles, pulse obstacle compensation.Документ Actual contact area on the worn clearance face of the cutter with the round kyborite insert(Національний технічний університет "Харківський політехнічний інститут", 2023) Manovytsky, Olersandr; Klymenko, Sergii; Klymenko, Serhii; Kopeikina, MarynaFor a tool equipped with a circular cutting insert, a dependence is proposed for calculating the nominal area of the contact area on the back surface. It is proved that the actual area of the contact area of the tool differs significantly from the nominal one due to the presence of a system of micro-irregularities, which makes a difference in the assessment of machining process parameters. Using the example of a tool equipped with a circular cutting insert made of polycrystalline cubic boron nitride ciborite, an approach to determining the actual contact area of the back surface with the workpiece during finishing turning of hardened steel is considered. The possibility of taking into account the influence of the system of irregularities in the contact area, determined by the parameters of its topography, on the size of the actual area is shown, and the ratio of the actual and nominal areas of the contact areas of the tool is determined, and it is found that, depending on the degree of development of the microrelief, the ratio of the actual and nominal areas of the contact surface of the cutter differs by at least 20%. It is shown that the actual contact area is also related to the total length of the main and auxiliary cutting edges, determined by the maximum values of the main and auxiliary angles in the cutter plan, and the size of the wear chamfer on the back surface of the cutter.Документ Adaptive resource allocation method for data processing and security in cloud environment(Національний технічний університет "Харківський політехнічний інститут", 2023) Petrovska, Inna; Kuchuk, HeorhiiSubject of research: methods of resource allocation of the cloud environment. The purpose of the research: to develop a method of resource allocation that will improve the security of the cloud environment. At the same time, effective data processing should be achieved. Method characteristics. The article discusses the method of adaptive resource allocation in cloud environments, focusing on its significance for data processing and enhanced security. A notable feature of the method is the consideration of external influences when calculating the characteristics of cloud resource requests and predicting resource requests based on a time series test. The main idea of this approach lies in the ability to intelligently distribute resources while considering real needs, which has the potential to optimize both productivity and confidentiality protection simultaneously. Integrating adaptive resource allocation methods not only improves data processing efficiency in cloud environments but also strengthens mechanisms against potential cyber threats. Research results. To ensure timely resource allocation, the NSGA-II algorithm has been enhanced. This allowed reducing the resolution time of multi-objective optimization tasks by 5%. Additionally, research results demonstrate that effective utilization of various types of resources on a physical machine reduces resource losses by 1.2 times compared to SPEA2 and NSGA-II methods.Документ Advantages and drawbacks of two-step approach to providing desired parameters in lossy image compression(Національний технічний університет "Харківський політехнічний інститут", 2024) Li, Fangfang; Abramov, Sergey; Dohtiev, Ihor; Lukin, VladimirThe object of the study is the process of lossy image compression. The subject of the study is the two-step approach to providing desired parameters (quality and compression ratio) for different coders. The goals of the study are to review advantages of the two-step approach to lossy compression, to analyze the reasons of drawbacks, and to put forward possible ways to get around these shortcomings. Methods used: linear approximation, numerical simulation, statistical analysis. Results obtained: 1) the considered approach main advantage is that, in most applications, it provides substantial improvement of accuracy of providing a desired value of a controlled compression parameter after the second step compared to the first step; 2) the approach is quite universal and can be applied for different coders and different parameters of lossy compression to be provided; 3) the main problems and limitations happen due to the use of linear approximation and essential difference in behavior of rate/distortion curves for images of different complexity; 4) there are ways to avoid the approach drawbacks that employ adaptation to image complexity and/or use certain restrictions at the second step. Conclusions: based on the results of the study, it is worth 1) considering more complex approximations of rate-distortion curves; 2) paying more attention to adequate and fast algorithms of characterizing image complexity before compression; 3) using quality metrics that have quasi-linear rate/distortion curves for a given coder.Документ Algorithms for finding non-intersecting roads on images(Національний технічний університет "Харківський політехнічний інститут", 2023) Goyushova, Ulviyya MalikResearch relevance The use of GPS for UAVs to determine their current coordinates (navigation) leads to a number of problems. The development and improvement of the autonomous navigation method without the use of GPS is an actual issue, and this issue is considered in the article. The subject of study in the article is the issue of UAVs navigation based on video images. The purpose of work to develop an algorithm for autonomous navigation of UAVs that requires less resources. The following tasks are solved in the article: software modules are developed based on image processing algorithms; suitable model for invariant identification of curves was studied and applied. The following results were obtained: an algorithm was developed for the invariant identification of winding roads (curves) without intersections from different angles; developed software modules have been tested in the Republic of Azerbaijan on the basis of a map of the region called "Agsu Pass". Conclusions: the application of the method proposed in the article will enable rotation-invariant autonomous navigation of UAVs using less resources.Документ Alteration of the cutting force components in tangential turning(Національний технічний університет "Харківський політехнічний інститут", 2023) Sztankovics, István; Pásztor, István T.In the development of cutting procedure, the study of the cutting force is important to evaluate the possible loads and elastic deformations in the machining system. The unusual relative position of the cutting tool leads to a changing characteristic of the cutting force in tangential turning. Therefore, it is particularly important to study the values and ratios of the cutting force components in different setups in this finishing procedure. In this paper the depth of cut, feed, and cutting speed are changed, and the effect of these parameters are analysed on the major cutting force, feed force and passive force. The full factorial design of experiment method is applied in the selection of setup parameters and the evaluation of the results. The maximal values and the ratio of the force components were analysed by the determination of equations.Документ An adaptive controller for power quality control in high speed railway with electric locomotives with asynchronous traction motors(Національний технічний університет "Харківський політехнічний інститут", 2024) Chaib Ras, A.; Bouzerara, R.; Bouzeria, H.Power quality in an electric railway system pertains to the dependability, consistency, and purity of the electrical power provided to different components and systems within the railway infrastructure. Assessing power quality offers considerable opportunities to improve the efficiency of railway systems. Problem. Managing the flow of active and reactive power effectively, decreasing harmonic currents, and addressing the negative sequence component are all critical parts of improving power quality for electrified rail systems. As a result, flexible AC transmission systems are the major means of minimizing or decreasing these difficulties. Purpose. This study describes a half-bridge reactive power railway power conditioner (HB-RPC) with a novel Ynev balancing transformer. HB-RPC is made up of four switching devices and two DC capacitors and the compensator’s stability is determined by the operating voltage of the DC-link. Any variations or imbalances in the DC voltage might cause the compensator to operate in an unstable manner. Novelty. Of a novel balanced transformer with HB-RPC in a high-speed railway system with two scenarios. Methods. The study utilized MATLAB/Simulink software for simulation purposes. The system integrates a fuzzy logic controller (FLC) and a PI controller to optimize DC voltage, ensuring its constancy and balance, with the objective of improving the overall stability of the system. Results. The simulation outcomes illustrate the efficacy of the control approach. Through a comparison of results between scenarios (two and four trains) with the PI-basedHB-RPC and the FLC-based-HB-RPC, the system exhibits enhanced stability for the proposed railway system when employing the FLCbased-HB-RPC, compared to a controller based on PI. Practical value. The proposed configuration elucidates its role in enhancing both the dynamic performance of the system and the power quality of the three-phase rail traction chain.Документ Analysis and comparison of the waste management development in Hungary and Slovakia(Національний технічний університет "Харківський політехнічний інститут", 2022) Akkad, M. Z.; Bányai, T.Waste production is an indispensable human process that happens daily in all communities. With the population increase and the industry developments, the waste amounts are growing, and their treating processes are taking a bigger share of the transportation and handling tasks in the city logistics. These waste collection, transportation, and treatment are described as waste management has been investigated and developed especially with the various application, solutions, and developments in the logistics, transportation, and industrial areas. Also, with the higher attention to the environmental impact in the different areas, the green aspect of waste management takes more importance particularly in city logistics where congestion occurs regularly. Within this work, waste management is analyzed in Europe generally and Hungary specifically. Eurostat database is used for that purpose next to previous research work tackling this topic. Also, a comparison between the waste management operations in Hungary and Slovakia is discussed to show the difference of these operations’ developments between the two countries between 2014 and 2020.Документ Analysis and testing of internal combustion engine driven linear alternator(Національний технічний університет "Харківський політехнічний інститут", 2023) Arslan, Serdal; Mellah, HaceneIntroduction. Internal combustion engine technology has been considered for the alternator system in the last two decades. Especially when considering fuel diversity, reliability, portability, power density, research studies are increasing day by day. In this respect, interest has been focused on linear generator studies. Purpose. The goal of the research is to investigate the performance of a linear generator and its application to generate electrical energy from an internal combustion engine to solve the range problem of small electric powered vehicles. The generator, unlike a traditional generator, consists of a linear generator with a crank mechanism driven by an internal combustion engine. Originality. The configuration of the linear generator with internal combustion engine crank has not previously been reported. Methods. The numerical solution of the generator was carried out by the finite element method in the Ansys Maxwell software in a cylindrical coordinate system. The effect of stroke length and frequency on voltage and output power was investigated by monitoring an external electrical load. A prototype linear generator has been designed and produced considering the sizing dimensions. The configuration can be used in power-hungry applications and increase the range of small electric vehicles. Results. The results from simulation and practice are largely in agreement. Practical value. A practical mechanical system was built comprising a linear generator connected to a 2.2 kW internal combustion engine via a crank connecting rod for analysis.Документ Analysis of marсovian systems with a given set of selected states(Національний технічний університет "Харківський політехнічний інститут", 2022) Raskin, Lev; Sukhomlyn, Larysa; Korsun, RomanAnalysis of stationary Marcovian systems is traditionally performed using systems of linear Kolmogorov differential equations. Such systems make it possible to determine the probability of the analyzed system being in each of its possible states at an arbitrary time. This standard task becomes more complicated if the set of possible states of systems is heterogeneous and some special subset can be distinguished from it, in accordance with the specifics of the system functioning. Subject of the study is technology development for such systems analysis. In accordance with this, the purpose of the work is to find the distribution law of the random duration of such a system's stay on a set of possible states until it falls into a selected subset of these states. Method for solving the problem is proposed based on splitting the entire set of possible states of the system into two subsets. The first of them contains a selected subset of states, and the second contains all the other states of the system. Now a subset of states is allocated from the second subset, from which a direct transition to the states of the first subset is possible. Next, a system of differential equations describing the transitions between the formed subsets is formed. The solution of this system of equations gives the desired result – distribution of the random duration of the system's stay until the moment of the first hit in the selected subset of states. The method allows solving a large number of practical problems, for example, in the theory of complex systems reliability with many different failure states. In particular, finding the law of the uptime duration distribution, calculating the average duration of uptime.Документ Analysis of selected function-defining 2D surface roughness parameters in tangential turning(Національний технічний університет "Харківський політехнічний інститут", 2023) Sztankovics, IstvánAmong other, more frequently analysed surface topography parameters, the function-defining parameters must be analysed in different machining procedures to outline their application possibilities. These values are the core roughness, the reduced peak height, the reduced valley depth, the skewness, and the kurtosis of the roughness profiles. Tangential turning is a promising machining procedure, which can produce ground-like surfaces with twist-free properties by defined cutting edged tools. The achievable productivity is also very high. Therefore, in this paper, these roughness parameters were analysed from 2D roughness profiles measured on surfaces machined by tangential turning.Документ Analysis of suitable converter for the implementation of drive system in solar photovoltaic panels(Національний технічний університет "Харківський політехнічний інститут", 2024) Themozhi, G.; Srinivasan, K.; Arun Srinivas, T.; Prabha, A.Introduction. Photovoltaic (PV) systems gained immense attraction in the recent years since it produces electricity without causing environmental pollution through direct conversion of solar irradiance into electricity. Solar PV panels produce DC power. The magnitude of this DC power varies with temperature and irradiance of the sun rays. The DC supply from solar panels can be regulated using DC-DC converter and then can further be converted into the desired AC voltage by means of a voltage source inverter before being fed to an induction motor (IM). The speed and torque of an IM, fed from PV arrays, can vary due to the variation in the output power of the panels. Goal of this work is to improve the dynamic performance and reduce the torque ripple of Cuk converter-inverter fed IM drive system. The novelty of the current work proposes interleaved Cuk converter between solar PV DC source and the inverter. Purpose. To provide continuous current using an interleaved Cuk converter to the IM drive and in turn to reduce the torque ripple in IM. Methodology. Introduced an interleaved Cuk converter which is a blend of Cuk converters connected in parallel with each other between solar PV arrays and IM drive system. Originality. Simulation results are obtained for Cuk converter and interleaved Cuk converter fed IM drive by means of MATLAB. The hardware setup for the same IM systems is developed. Practical value. Simulation and hardware results are coincided with each other and it is subject from the simulation and hardware results that the interleaved Cuk converter-inverter fed IM system produced results superior than the Cuk converter inverter fed IM drive system. References 25, table 2, figures 22.Документ Analysis of text augmentation algorithms in artificial language machine translation systems(Національний технічний університет "Харківський політехнічний інститут", 2023) Havrashenko, Anton; Barkovska, OlesiaThe work is devoted to the development of an organizational model of the machine translation system of artificial languages. The main goal is the analysis of text augmentation algorithms, which are significant elements of the developed machine translation system at the stage of improvement of new dictionaries created on the basis of already existing dictionaries. In the course of the work was developed a model of the machine translation system, created dictionaries based on texts and based on already existing dictionaries using augmentation methods such as back translation and crossover; improved dictionary based on algorithms of n-grams, Knuth-Morris-Pratt and word search in the text (such as binary search, tree search, sqrt decomposition). In addition, the work implements the possibility of using the prepared dictionary for translation. Obtained results can improve existing systems of machine translation of the text of artificial languages. Practical significance of this work is the analysis and improvement of text augmentation algorithms by changing the prefix tree type. Compared to the conventional algorithm, the improved algorithm reduced the memory usage by almost 13 times, which allows it to be used on much larger test data. This was achieved by changing the internal system of the node of the prefix tree from constant references to an expandable list.