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S. M. Babchuk, Т. V. Humeniuk, I. T. Romaniv
Radio Electronics, Computer Science, Control, Volume 1, pp 46-56; doi:10.15588/1607-3274-2021-1-5

Abstract:
Context. High-performance computing systems are needed to solve many scientific problems and to work with complex applied problems. Previously, real parallel data processing was supported only by supercomputers, which are very limited and difficult to access. Currently, one way to solve this problem is to build small, cheap clusters based on single-board computers Raspberry Pi. Objective. The goal of the work is the creation of a complex criterion for the efficiency of the cluster system, which could properly characterize the operation of such a system and find the dependences of the performance of the cluster system based on Raspberry Pi 3B+ on the number of boards in it with different cooling systems. Method. It is offered to apply in the analysis of small cluster computer systems the complex criterion of efficiency of work of cluster system which will consider the general productivity of cluster computer system, productivity of one computing element in cluster computer system, electricity consumption by cluster system, electricity consumption per one computing element, the cost of calculating 1 Gflops cluster computer system, the total cost of the cluster computer system. Results. The developed complex criterion of cluster system efficiency was used to create an experimental cluster system based on single-board computers Raspberry Pi 3B+. Mathematical models of the dependence of the performance of a small cluster system based on single-board computers Raspberry Pi 3B+ depending on the number of boards in it with different cooling systems have also been developed. Conclusions. The conducted experiments confirmed the expediency of using the developed complex criterion of efficiency of the cluster system and allow to recommend it for use in practice when creating small cluster systems. Prospects for further research are to determine the weights of the constituent elements of the complex criterion of efficiency of the cluster system, as well as in the experimental study of the proposed weights.
A. Ya. Bomba, I. P. Moroz, M. V. Boichura
Radio Electronics, Computer Science, Control, Volume 1, pp 14-28; doi:10.15588/1607-3274-2021-1-2

Abstract:
Context. P-i-n-diodes are widely used in a microwave technology to control the electromagnetic field. The field is controlled by the formation of an electron-hole plasma in the region of an intrinsic semiconductor (i-region) under the influence of a control current. The development of control devices on p-i-n-diodes has led to the emergence of integral p-i-n-structures of various types, the characteristics of which (for example, switching speed, switched power level, etc.) exceed the similar characteristics of volume diodes. The properties of p-i-n-structures are determined by a number of processes: the diffusion-drift charge transfer process, the recombination-generation, thermal, injection, and the so on. Obviously, these processes should be taken into account (are displayed) in the mathematical model of the computer-aided design system for control devices of a microwave systems. Integrated process accounting leads to the formulation of complex tasks. One of them is the task of optimizing the shape, geometric dimensions and placement of the injected contacts (an active region). Objective. The goal of the work is the development of a mathematical model and the corresponding software of the process of a microwave waves interaction with electron-hole plasma in an active region of the surface-oriented integral p-i-n-structures with ribbon-type freeform contacts to optimize an active region shape and its geometric dimensions. Method. The main idea of the developed algorithm is to use the conformal mapping method to bring the physical domain of the problem to canonical form, followed by solving internal boundary value problems in this area for the ambipolar diffusion equation and the wave equation using numerical-analytical methods (the finite difference method; partial domains method using projection boundary conditions similar to the Galerkin method). The optimization algorithm is based on a phased solution of the following problems (the shape and geometric dimensions of the active region are specified at each stage): a computational grid of nodes for the physical regions of the problem is being found, in an active region the carriers concentration distribution is being determined and the energy transmitted coefficient in the system under study is being calculated, which is used in the proposed optimization functional. The extreme values of the functional are found by the uniform search method. Results. The proposed mathematical model and the corresponding algorithm for optimizing the shape and geometric dimensions of the active region (i-region) of integrated surface-oriented p-i-n-structures expands the tool base for the design of semiconductor circuits of microwave frequencies (for example, similar to CST MICROWAVE STUDIO). Conclusions. An algorithm has been developed to optimize the shape and geometrical dimensions of the active region of integrated surface-oriented p-i-n-structures with in-depth contacts intended for switching millimeter-wave electromagnetic signals. The universality of the algorithm is ensured by applying the method of conformal transformations of spatial domains. The example of the application of the proposed algorithm to search for the optimal sizes of wedge-shaped (in cross-section) contacts of silicon structures is considered.
P. S. Nosov, V. V. Cherniavskyi, S. M. Zinchenko, I. S. Popovych, Ya. А. Nahrybelnyi, H. V. Nosova
Radio Electronics, Computer Science, Control, Volume 1, pp 208-223; doi:10.15588/1607-3274-2021-1-20

Abstract:
Context. The article introduces an approach for analyzing the reactions of a marine electronic navigation operator as well as automated identification of the likelihood of the negative impact of the human factors in ergatic control systems for sea transport. To meet the target algorithms for providing information referring to the results of human-machine interaction of an operator in marine emergency response situations while managing increasing complexity of navigation operations’ carrying out are put forward. Objective. The approach delivers conversion of the operator’s actions feature space into a logical-geometric one of p-adic systems making the level of the operator’s intellectual activity by using automated means highly likely to be identified. It is sure to contribute to its dynamic prediction for the sake of further marine emergency situations lessening. Method. Within the framework of the mentioned above approach attaining objective as automated identification of the segmented results of human-machine interactions a method for transforming deterministic fragments of an operator’s intellectual activity in terms of p-adic structures is proposed to be used. To cope with such principles as specification, generalization as well as transitions to different perception spaces of the navigation situation by the operator are said to be formally specified. Having been carried out of simulation modeling has turned out to confirm the feasibility of the proposed above approach causing, on the grounds of temporary identifiers, the individual structure of the operator’s reactions to be determined. As a result, the data obtained has delivered the possibility of having typical situations forecasted by using automated multicriteria methods and tools. This issue for its part is said to be spotted as identification of individual indicators of the operator’s reaction dynamics in complex man-machine interaction. Results. In order to have the proposed formal-algorithmic approach approved an experiment was performed using the navigation simulator Navi Trainer 5000 (NTPRO 5000). Automated analysis of experimental server and video data have furnished the means of deterministic operator actions identification in the form of metadata of the trajectory of his reactions within the space of p-adic structures. Thus, the results of modeling involving automated neural networks are sure to facilitate the time series of the intellectual activity of the electronic marine navigation operator to be identified and, therefore, to predict further reactions with a high degree of reliability. Conclusions. The proposed formal research approaches combined with the developed automated means as well as algorithmic and methodological suggestions brought closer to the objectives for solving the problem of automated identification of the negative impact of the human factors of the electronic navigation operator on a whole new level. The efficiency of the proposed approach is noticed to have been approved by the results of automated processing of experimental data and built forecasts.
S. S. Shevelev
Radio Electronics, Computer Science, Control, Volume 1, pp 194-207; doi:10.15588/1607-3274-2021-1-19

Abstract:
Context. Modern general purpose computers are capable of implementing any algorithm, but when solving certain problems in terms of processing speed they cannot compete with specialized computing modules. Specialized devices have high performance, effectively solve the problems of processing arrays, artificial intelligence tasks, and are used as control devices. The use of specialized microprocessor modules that implement the processing of character strings, logical and numerical values, represented as integers and real numbers, makes it possible to increase the speed of performing arithmetic operations by using parallelism in data processing. Objective. To develop principles for constructing microprocessor modules for a modular computing system with a reconfigurable structure, an arithmetic-symbolic processor, specialized computing devices, switching systems capable of configuring microprocessors and specialized computing modules into a multi-pipeline structure to increase the speed of performing arithmetic and logical operations, high-speed design algorithms specialized processors-accelerators of symbol processing. To develop algorithms, structural and functional diagrams of specialized mathematical modules that perform arithmetic operations in direct codes on neural-like elements and systems for decentralized control of the operation of blocks. Method. An information graph of the computational process of a modular system with a reconstructed structure has been built. Structural and functional diagrams, algorithms that implement the construction of specialized modules for performing arithmetic and logical operations, search operations and functions for replacing occurrences in processed words have been developed. Software has been developed for simulating the operation of an arithmetic-symbolic processor, specialized computing modules, and switching systems. Results. A block diagram of a reconfigurable computing modular system has been developed, which consists of compatible functional modules, it is capable of static and dynamic reconfiguration, has a parallel structure for connecting the processor and computing modules through the use of interface channels. The system consists of an arithmetic-symbolic processor, specialized computing modules and switching systems, performs specific tasks of symbolic information processing, arithmetic and logical operations. Conclusions. The architecture of reconfigurable computing systems can change dynamically during their operation. It becomes possible to adapt the architecture of a computing system to the structure of the problem being solved, to create problem-oriented computers, the structure of which corresponds to the structure of the problem being solved. As the main computing element in reconfigurable computing systems, not universal microprocessors are used, but programmable logic integrated circuits, which are combined using high-speed interfaces into a single computing field. Reconfigurable multipipeline computing systems based on fields are an effective tool for solving streaming information processing and control problems.
P. Kravets, V. Lytvyn, V. Vysotska
Radio Electronics, Computer Science, Control, Volume 1, pp 172-183; doi:10.15588/1607-3274-2021-1-17

Abstract:
Context. In today’s information society with advanced telecommunications through mobile devices and computer networks, it is important to form a variety of virtual organizations and communities. Such virtual associations of people by professional or other interests are designed to quickly solve various tasks: to perform project tasks, create startups to attract investors, network marketing, distance learning, solving complex problems in science, economics and public administration , construction of various Internet services, discussion of political and social processes, etc. Objective of the study is to develop an adaptive Markov recurrent method based on the stochastic approximation of the modified condition of complementary non-rigidity, valid at Nash equilibrium points for solving the problem of game coverage of projects. Method. In this work the multiagent game model for formation of virtual teams of executors of projects on the basis of libraries of subject ontologies is developed. The competencies and abilities of agents required to carry out projects are specified by sets of ontologies. Intelligent agents randomly, simultaneously and independently choose one of the projects at discrete times. Agents who have chosen the same project determine the current composition of the team of its executors. For agents’ teams, a current penalty is calculated for insufficient coverage of competencies by the combined capabilities of agents. This penalty is used to adaptively recalculate mixed player strategies. The probabilities of selecting those teams whose current composition has led to a reduction in the fine for non-coverage of ontologies are increasing. During the repetitive stochastic game, agents will form vectors of mixed strategies that will minimize average penalties for non-coverage of projects. Results. For solve the problem of game coverage of projects, an adaptive Markov recurrent method based on the stochastic approximation of the modified condition of complementary non-rigidity, valid at Nash equilibrium points, was developed. Conclusions. Computer simulation confirmed the possibility of using the stochastic game model to form teams of project executors with the necessary ontological support in conditions of uncertainty. The convergence of the game method is ensured by compliance with the fundamental conditions and limitations of stochastic optimization. The reliability of experimental studies is confirmed by the repeatability of the results obtained for different sequences of random variables.
D. O. Progonov
Radio Electronics, Computer Science, Control, Volume 1, pp 184-193; doi:10.15588/1607-3274-2021-1-18

Abstract:
Context. The problem of sensitive information protection during data transmission in communication systems was considered. The case of reliable detection of stego images formed according to advanced embedding methods was investigated. The object of research is digital images steganalysis of adaptive steganographic methods. Objective. The goal of the work is performance analysis of statistical stegdetectors for adaptive embedding methods in case of preliminary noising of analyzed image with thermal and shot noises. Method. The image pre-processing (calibration) method was proposed for improving stego-to-cover ratio for state-of-the-art adaptive embedding methods HUGO, MG and MiPOD. The method is aimed at amplifying negligible changes of cover image caused by message hiding with usage of Gaussian and Poisson noises. The former one is related to influence the thermal noise of chargecoupled device (CCD) based image sensor during data acquisition. The latter one is related to shot noise that originates from stochastic process of electron emission by photons hitting of CCD elements. During the research, parameters of thermal noise were estimated with two-dimensional Wiener filter, while sliding window of size 5·5 pixels was used for parameters evaluation for shot noise. Results. The dependencies of detection error on cover image payload for advance HUGO, MG and MiPOD embedding methods were obtained. The results were presented for the case of image pre-noising with both Gaussian and Poisson noises, and varying of feature pre-processing methods. Conclusions. The conducted experiments confirmed effectiveness of proposed approach for image calibration with Poisson noise. Obtained results allow us to recommend linearly transformed features to be used for improving stegdetector performance by natural image processing. The prospects for further research may include investigation usage of special noises, such as fractal noises, for improving stego-to-cover ratio for advanced embedding methods.
L. A. Kleiman, V. I. Freyman
Radio Electronics, Computer Science, Control, Volume 1, pp 158-171; doi:10.15588/1607-3274-2021-1-16

Abstract:
Context. In the modern world, information management systems have become widespread. This make it possible to automate the technological processes of enterprises of various sizes. Many information management systems include wireless and autonomous elements. Autonomy, in this case, means the ability of the system elements to function for a certain time without additional energy supply. In this regard, such a parameter of operational reliability as the battery life of a system element becomes one of the most important. One of the main tools for improving the reliability and fault tolerance of information management system elements – is the use of a modern diagnostic system. Objective. The aim of the work is to develop a method for increasing the reliability of the functioning of autonomous elements of information management systems. It includes the creation of a model of an information management system and an algorithm for reasonable redistribution of diagnostic functions, as well as a software implementation of the developed algorithm, which confirms its higher reliability indicators in comparison with other algorithms. Methods. The basic model was the Preparata-Metz-Chen model. On its basis, a new model of the system was built, including the structural and logical description of the elements and the determination of the way of their interaction. The elements were classified by the degree of criticality of the functions performed in the system. On the basis of the developed model and description of the elements, an algorithm was developed for the reasonable redistribution of the diagnostic load, which made it possible to reduce the average energy consumption of the elements and thereby improve the reliability indicators. A software implementation of the developed algorithm was created, which allows to numerically evaluate its advantages. The developed and existing algorithms were compared. Results. A model of information management system has been developed. In such a system, it is proposed to use an integrated test diagnostics system. This diagnostic system implements algorithms for redistributing the diagnostic load. To determine the importance of the characteristics taken into account, a linear criterion was chosen, as the most studied and fastest in application. A software model, that implements the developed algorithm and makes it possible to compare it with existing algorithms, has been developed. A study of the software model with various parameters was carried out and, based on the results of the software simulation, conclusions were drawn about the possibilities of improving the algorithm and directions for further scientific research were formulated. Conclusions. The usage of the developed algorithm makes it possible to increase such a characteristic of the reliability of the elements of the information and control system as the mean time of failure-free operation (mean time between failures) by increasing the operating time of autonomous elements without recharging. When carrying out software modeling of the developed and existing algorithms, the advantages of the first were confirmed, and theoretical possibilities for its improvement were formulated.
G. M. Babeniuk
Radio Electronics, Computer Science, Control, Volume 1, pp 144-157; doi:10.15588/1607-3274-2021-1-15

Abstract:
Context. The main purpose of Correlation Extremal Navigation system is finding coordinates in case of absence of Global Positioning System signal and as a result high-accuracy maps as the main source of information for finding coordinates are very important. Magnetic field map as the main source of information can include errors values, as an example: not good enough equipment or human factor can cause error value of measurements. Objective. In order to create high-accuracy maps given work proposes to improve the process of creating magnetic field maps. The given work represents delay tolerant networking as an additional approach for data transmission between magnetic observatory and magnetic station and its improvement. Method. Improved Dijkstra’s algorithm together with Ford-Fulkerson’s algorithm for finding path with minimum capacity losses, earliest delivery time and maximum bit rate in case of overlapping contacts should be represented in the given work because nowadays, delay tolerant networking routing protocols do not take into account the overlap factor and resulting capacity losses and it leads to big problems Results. For the first time will be presented algorithm that chooses the route that guarantees the minimum of capacity losses, earliest delivery time and maximum bit rate in the delay tolerant networking with overlapping contacts and increases the probability of successful data transmission between magnetic stations and magnetic observatories. Conclusions. In order to perform high-accuracy measurement of magnetic field group of people allocate their equipment for magnetic field measurement in remote areas in order to avoid the influence of environment on measurements of magnetometer. Since magnitude of magnetic field can vary dependent on temperature, proximity to the ocean, latitude (diurnal variation of magnetic field) and magnetic storms magnetic station from time to time adjusts its measurements with a help of reference values of magnetic field (magnetic station sends request for reference values to magnetic observatory). The problem of the given approach is that remote areas usually are not covered by network (no Internet) and as a result the adjustment of measurements is impossible. In order to make adjustment of measurements possible and as a result improve accuracy of magnetic maps given work proposed the usage of Delay Tolerant Networking that delivers internet access to different areas around the world and represented its improvement to make its approach even better.The results are published for the first time.
M. A. Novotarskyi, S. G. Stirenko, Y. G. Gordienko, V. A. Kuzmych
Radio Electronics, Computer Science, Control, Volume 1, pp 136-143; doi:10.15588/1607-3274-2021-1-14

Abstract:
Context. Machine learning is one of the actively developing areas of data processing. Reinforcement learning is a class of machine learning methods where the problem involves mapping the sequence of environmental states to agent’s actions. Significant progress in this area has been achieved using DQN-algorithms, which became one of the first classes of stable algorithms for learning using deep neural networks. The main disadvantage of this approach is the rapid growth of RAM in real-world tasks. The approach proposed in this paper can partially solve this problem. Objective. The aim is to develop a method of forming the structure and nature of access to the sparse distributed memory with increased information content to improve reinforcement learning without additional memory. Method. A method of forming the structure and modification of sparse distributed memory for storing previous transitions of the actor in the form of prototypes is proposed. The method allows increasing the informativeness of the stored data and, as a result, to improve the process of creating a model of the studied process by intensifying the learning of the deep neural network. Increasing the informativeness of the stored data is the result of this sequence of actions. First, we compare the new transition and the last saved transition. To perform this comparison, this method introduces a rate estimate for the distance between transitions. If the distance between the new transition and the last saved transition is smaller than the specified threshold, the new transition is written in place of the previous one without increasing the amount of memory. Otherwise, we create a new prototype in memory while deleting the prototype that has been stored in memory the longest. Results. The work of the proposed method was studied during the solution of the popular “Water World” test problem. The results showed a 1.5-times increase in the actor’s survival time in a hostile environment. This result was achieved by increasing the informativeness of the stored data without increasing the amount of RAM. Conclusions. The proposed method of forming and modifying the structure of sparse distributed memory allowed to increase the informativeness of the stored data. As a result of this approach, improved reinforcement learning parameters on the example of the “Water World” problem by increasing the accuracy of the model of the physical process represented by a deep neural network.
Т. V. Neskorodieva, E. E. Fedorov
Radio Electronics, Computer Science, Control, Volume 1, pp 127-135; doi:10.15588/1607-3274-2021-1-13

Abstract:
Context. The analytical procedures used in the audit are currently based on data mining techniques. The work solves the problem of increasing the efficiency and effectiveness of analytical audit procedures by clustering based on spectral decomposition. The object of the research is the process of auditing the compliance of payment and supply sequences for raw materials. Objective. The aim of the work is to increase the effectiveness and efficiency of the audit due to the method of spectral clustering of sequences of payment and supply of raw materials while automating procedures for checking their compliance. Method. The vectors of features are generated for the objects of the sequences of payment and supply of raw materials, which are then used in the proposed method. The created method improves the traditional spectral clustering method by automatically determining the number of clusters based on the explained and sample variance rule; automatic determination of the scale parameter based on local scaling (the rule of K-nearest neighbors is used); resistance to noise and random outliers by replacing the k-means method with a modified PAM method, i.e. replacing centroid clustering with medoid clustering. As in the traditional approach, the data can be sparse, and the clusters can have different shapes and sizes. The characteristics of evaluating the quality of spectral clustering are selected. Results. The proposed spectral clustering method was implemented in the MATLAB package. The results obtained made it possible to study the dependence of the parameter values on the quality of clustering. Conclusions. The experiments carried out have confirmed the efficiency of the proposed method and allow us to recommend it for practical use in solving audit problems. Prospects for further research may lie in the creation of intelligent parallel and distributed computer systems for general and special purposes, which use the proposed method for segmentation, machine learning and pattern recognition tasks.
S. Y. Gavrylenko, I. V. Sheverdin
Radio Electronics, Computer Science, Control, Volume 1, pp 105-116; doi:10.15588/1607-3274-2021-1-11

Abstract:
Context. The problem of identification a computer system state was investigated. The object of the research is the identification process of the computer system state. The subject of the research is computer system state identifying means and methods. Objective. The purpose of the work is to develop a method for identifying the computer system state. Method. The method has been developed for identifying a computer system state based on integrated use the procedure for grouping unlabeled initial data and using machine learning technology based on the «Isolation Forest» algorithm, which provides to identify a computer system state and to distinguished the process name that initiated the abnormal state. Therefore, for collecting statistical data in the form of operating system functioning events, data method has been proposed and developed along with software. The analysis of functioning events has been performed. The result of analysis showed that the most informative are read and write operations. To set up a single dataset, read and write operations compared with the process name and combined into one array of event groups, so that it is possible to single out the process that causes the abnormal state of the computer system. As a result of the research, the «Isolation Forest» algorithm has been selected as a component of the method for identifying the computer system state. An accuracy and efficiency assessment of the developed method of identifying a computer system state has been carried out. Results. The developed method is implemented and investigated when solving the problem of identifying anomalies in the functioning of computer systems. Conclusions. The experiments carried out confirmed the efficiency of the proposed method. It allows us recommended the method for practical use in order to improve efficiency of identifying the computer system state and use it as an express method. Areas for further research may lie in the creation of the ensemble of fuzzy trees based on the proposed method and optimization of this software implementation.
V. N. Tarasov
Radio Electronics, Computer Science, Control, Volume 1, pp 87-96; doi:10.15588/1607-3274-2021-1-9

Abstract:
Context. Studies of G/G/1 systems in queuing theory are relevant because such systems are of interest for analyzing the delay of data transmission systems. At the same time, it is impossible to obtain solutions for the delay in the final form in the general case for arbitrary laws of distribution of the input flow and service time. Therefore, it is important to study such systems for particular cases of input distributions. We consider the problem of deriving a solution for the average queue delay in a closed form for two systems with ordinary and shifted hypererlangian and erlangian input distributions. Objective. Obtaining a solution for the main characteristic of the system – the average delay of requests in the queue for two queuing systems of the G/G/1 type with ordinary and with shifted hypererlangian and erlangian input distributions. Method. To solve this problem, we used the classical method of spectral decomposition of the solution of the Lindley integral equation. This method allows to obtaining a solution for the average delay for systems under consideration in a closed form. The method of spectral decomposition of the solution of the Lindley integral equation plays an important role in the theory of systems G/G/1. For the practical application of the results obtained, the well-known method of moments of probability theory is used. Results. For the first time, spectral expansions of the solution of the integral Lindley equation for two systems are obtained, with the help of which calculation formulas for the average delay in a queue in a closed form are derived. Thus, mathematical models of queuing delay for these systems have been built. Conclusions. These formulas expand and supplement the known queuing theory formulas for the average delay G/G/1 systems with arbitrary laws distributions of input flow and service time. This approach allows us to calculate the average delay for these systems in mathematical packages for a wide range of traffic parameters. In addition to the average delay, such an approach makes it possible to determine also moments of higher orders of waiting time. Given the fact that the packet delay variation (jitter) in telecommunications is defined as the spread of the delay from its average value, the jitter can be determined through the variance of the delay.
S. D. Leoshchenko, S. A. Subbotin, A. O. Oliinyk, O. E. Narivs’Kiy
Radio Electronics, Computer Science, Control, Volume 1, pp 117-126; doi:10.15588/1607-3274-2021-1-12

Abstract:
Context. The problem of determining the optimal topology of a neuromodel, which is characterized by a high level of logical transparency in modeling complex technical systems, is considered. The object of research is the process of applying an indicator system to simplify and select the topology of neuromodels. Objective of the work is to develop and use a system of indicators to determine the level of complexity of the modeling problem and gradually select the optimal logically transparent topology of the neuromodel. Method. A method is proposed for selecting an optimal, logically transparent neural network topology for modeling complex technical systems using a system of corresponding indicators. At the beginning, the method determines the overall level of complexity of the modeling task and, using the obtained estimate, determines the method for further optimization of the neuromodel. Then, using Task data and input data characteristics, the method allows to obtain the most optimal structure of the neural model for further modeling of the system. The method reduces trainingvtime and increases the level of logical transparency of neuromodels, which significantly expands the practical use of such models, without using neuroevolution methods, which may not be justified by resource-intensive tasks. Results. The developed method is implemented and investigated in solving the problem of modeling the dynamics of pitting processes of steel alloys. Using the developed method made it possible to reduce the training time of the model by 22%, depending on the computing resources used. The method also increased the level of logical transparency of the model by reducing the number of computing nodes by 50%, which also indicates faster and more efficient use of resources. Conclusions. The conducted experiments confirmed the operability of the proposed mathematical support and allow us to recommend it for use in practice in the design of topologies of neuromodels for further solving modeling, diagnosis and evaluation problems. Prospects for further research may consist in the development of methods for structural optimization of previously synthesized models and the development of new methods for feature selection.
Ye. V. Bodyanskiy, A. Yu. Shafronenko, I. N. Klymova
Radio Electronics, Computer Science, Control, Volume 1, pp 97-104; doi:10.15588/1607-3274-2021-1-10

Abstract:
Context. In most clustering (classification without a teacher) tasks associated with real data processing, the initial information is usually distorted by abnormal outliers (noise) and gaps. It is clear that “classical” methods of artificial intelligence (both batch and online) are ineffective in this situation.The goal of the paper is to propose the procedure of fuzzy clustering of incomplete data using credibilistic approach and similarity measure of special type. Objective. The goal of the work is credibilistic fuzzy clustering of distorted data, using of credibility theory. Method. The procedure of fuzzy clustering of incomplete data using credibilistic approach and similarity measure of special type based on the use of both robust goal functions of a special type and similarity measures, insensitive to outliers and designed to work both in batch and its recurrent online version designed to solve Data Stream Mining problems when data are fed to processing sequentially in real time. Results. The introduced methods are simple in numerical implementation and are free from the drawbacks inherent in traditional methods of probabilistic and possibilistic fuzzy clustering data distorted by abnormal outliers (noise) and gaps. Conclusions. The conducted experiments have confirmed the effectiveness of proposed methods of credibilistic fuzzy clustering of distorted data operability and allow recommending it for use in practice for solving the problems of automatic clusterization of distorted data. The proposed method is intended for use in hybrid systems of computational intelligence and, above all, in the problems of learning artificial neural networks, neuro-fuzzy systems, as well as in the problems of clustering and classification.
A. Yu. Perevaryukha
Radio Electronics, Computer Science, Control, Volume 1, pp 78-86; doi:10.15588/1607-3274-2021-1-8

Abstract:
Context. In modern conditions occur abrupt changes in ecosystems. The species composition of Caspian Sea is changing rapidly. The dynamics of populations acquires an extreme character with the development of rapid invasions. The mathematical description of scale transformations requires new modeling methods. Complicated population regimes of changes have features of the threshold phenomenon in process of its development. Objective. We set the goal of computational modeling of practically important scenarios – groups of situations that relate to extreme and transitional dynamics of ecosystems, like outbreaks at the onset of dangerous invasions. We are developing a method that, on the basis of the survival model of generations, will conduct a description of sudden transitions to rapid but limited outbreak of numbers or, on contrary, a collapse of stocks like Atlantic cod in 1992 or Peruan anchovy Engraulis ringens in 1985. The purpose of our modeling is to improve the accuracy of forecasts of the population size when experts are estimates a rational strategy for the exploitation of biological resources. Method. Situations of abrupt but short-term changes in population processes cannot be calculated by traditional mathematical models and expressed in terms of asymptotic dynamics – closed limit trajectory sets. The basis of the idea of the method proposed by us is the formalization of nonlinear efficiency of reproduction, which changes in a threshold manner only in strictly defined environmental conditions. We use continuous-discrete time in the model for early ontognosis of the cod fish and insect pests. The method with triggers allows us to take into account in simulation experiments logic and motivation of making decisions by experts, people who manage the strategy of exploiting biological resources. Models assess variability for development of situations Results. We have implemented new method of bounded trigger functionals into hybrid system of the equations, that acting in selected specific states of biosystems. Analysis of new model scenarios with modifications of functionals in the basic hybrid system for extreme situations in fish and insect pests is carried out. Conclusions. We consider the method to be universal, since selection of the functional can be adapted to a wide class of models using differential equations on a fixed interval.
N. D. Koshevoy, V. V. Muratov, A. L. Kirichenko, S. A. Borisenko
Radio Electronics, Computer Science, Control, Volume 1, pp 57-65; doi:10.15588/1607-3274-2021-1-6

Abstract:
Context. An application of the method of a “jumping frogs” search algorithm to construct optimal experiment plans for cost (time) in the study of technological processes and systems that allow the implementation of an active experiment on them is proposed. The object of study are optimization methods for cost (time) costs of experimental designs, based on the application of a “jumping frogs” search algorithm. Objective. To obtain optimization results by optimizing the search of a “jumping frogs” search algorithm for the cost (time) costs of plans for a full factorial experiment. Method. A method is proposed for constructing a cost-effective (time) implementation of an experiment planning matrix using algorithms for searching for “jumping frogs”. At the beginning, the number of factors and the cost of transitions for each factor level are entered. Then, taking into account the entered data, the initial experiment planning matrix is formed. Then, taking into account the entered data, the initial matrix of experiment planning is formed. The “jumping frogs” method determines the “successful frog” by the lowest cost of transitions between levels for each of the factors. After that, the permutations of the “frogs” are performed. The “frog” strives for the most “successful” and, provided it stays close, remains in the location. Then the gain is calculated in comparison with the initial cost (time) of the experiment. Results. Software has been developed that implements the proposed method, which was used to conduct computational experiments to study the properties of these methods in the study of technological processes and systems that allow the implementation of an active experiment on them. The experimental designs that are optimal in terms of cost (time) are obtained, and the winnings in the optimization results are compared with the initial cost of the experiment. A comparative analysis of optimization methods for the cost (time) costs of plans for a full factorial experiment is carried out. Conclusions. The conducted experiments confirmed the operability of the proposed method and the software that implements it, and also allows us to recommend it for practical use in constructing optimal experiment planning matrices.
M. V. Novozhylova, V. A. Andronov, R. S. Melezhik
Radio Electronics, Computer Science, Control, Volume 1, pp 66-77; doi:10.15588/1607-3274-2021-1-7

Abstract:
Context. The urgency of the research is to develop methods for analyzing and processing space-time information, namely the set of data distributed both in space and time and creating on this basis a computer probabilistic model of the process of predicting manmade emergencies on city engineering infrastructure. The spatio-temporal nature of data series causes additional requirements for the identification procedures of the mathematical model of a series, therefore, the number of approaches identifying its structure and construction of a series model has been proposed. Objective is methodical and software implementation of a computer model of the space-time series being intended to predict the future values of locations and times of man-made emergencies on the engineering infrastructure of the metropolis and increase decision-making efficiency. Method. A projection approach providing independent determination of random spatial parameters defining location of emergency units on engineering infrastructure as a sequence of two one-dimensional uniform distributions and describing time distribution of moments of accidents as non-stationary Poisson distribution has been developed. Proposed is an integrated approach which includes the construction of generator points, the power of which (characteristic of the accident complexity) based on the implementation of the comparative statics approach with so-called cumulative effect within a certain time. A relaxation approach based on the reduction of a two-dimensional simulation model of determining the city of possible emergency location to a set of independent onedimensional non-stationary (including stationary) distributions to generate the time of occurrence has been constructed. Formalization of the space-time field, procedures of information support of the process of forecasting the parameters of a possible emergency, typification of initial data for numerical experiments on the implementation of methods for forecasting the parameters of a possible emergency on the example of water supply and sewerage network of utility company Kharkivvodokal, city Kharkiv have been developed. Results. A dual methodology to determine the simulation model parameters of the space-time series, which contains both projection and integral approaches, as well as a combined method − relaxation approach, have been proposed. Numerical experiments based on the constructed model were performed. The model being considered is the theoretical basis to construct the forecast using a large amount of historical data. Conclusions. The method to predict the parameters of space-time series considering the nonstationarity property of the time component distribution has been further developed. Using the proposed computer simulation tools allows to increase the accuracy of the forecast of the location, time of occurrence and severity of a possible accident on the engineering infrastructure of the metropolis.
S. F. Tyurin, A. Yu. Skornyakova, Y. A. Stepchenkov, Y. G. Diachenko
Radio Electronics, Computer Science, Control, Volume 1, pp 36-45; doi:10.15588/1607-3274-2021-1-4

Abstract:
Context. Self-Timed Circuits, proposed by D. Muller on the rise of the digital era, continues to excite researchers’ minds. These circuits started with the task of improving performance by taking into account real delays. Then Self-Timed Circuits have moved into the field of green computing. At last, they are currently positioned mainly in the field of fault tolerance. There is much redundancy in Self-Timed Circuits. It is believed that Self-Timed Circuits approaches will be in demand in the nano-circuitry when a synchronous approach becomes impossible. Strictly Self-Timed Circuits check transition process completion for each gate’s output. For this, they use so-called D. Muller elements (C-elements, hysteresis flip-flops, G-flip-flops). Usually, Self-Timed Circuits are designed on Uncommitted Logic Array. Now an extensive base of Uncommitted Logic Array Self-Timed gates exists. It is believed that SelfTimed Circuits are not compatible with FPGA technology. However, attempts to create self-timed FPGAs do not stop. The article proposes a Self-Timed Lookup Table for the Self-Timed Uncommitted Logic Array and the Self-Timed FPGA, carried out either by constants or utilizing additional memory cells. Authors proposed 1,2 – Self-Timed Lookup Table and described simulation results. Objective. The work’s goal is the analysis and design of the Strictly Self-Timed universal logic element based on Uncommitted Logic Array cells and pass-transistors circuits. Methods. Analysis and synthesis of the Strictly Self-Timed circuits with Boolean algebra. Simulation of the proposed element in the CAD “ARC”, TRANAL program, system NI Multisim by National Instruments Electronics Workbench Group, and layout design by Microwind. The reliability theory and reliability calculations in PTC Mathcad. Results. Authors designed, analyzed, and proved the Self-Timed Lookup Table’s workability for the Uncommitted Logic Arrays and FPGAs. Layouts of the novel logic gates are ready for manufacturing. Conclusions. The conducted studies allow us to use proposed circuits in perspective digital devices.
А. V. Bulashenko
Radio Electronics, Computer Science, Control, Volume 1, pp 7-13; doi:10.15588/1607-3274-2021-1-1

Abstract:
Context. 5G network is able to improve existing services and provide a new quality of services. 5G communication networks combine various radio technologies and technologies of fixed communication networks, therefore they are often called heterogeneous, which emphasizes their difference from other networks. One of the main features of such networks is over-density and ultra-low latency. It is the Internet of things that is the basic component of the concept of super dense networks. 3GPP suggests planning 5G networks based on the condition that 1 million devices is 1 km2. Also, ultra-low latency communications networks have a big impact on networking methods, especially for the tactile Internet concept. Such networks require decentralization through 1 ms delay requirements. This requires new approaches to building a new generation of networks, which is the reason for the development of new technologies. One such technology is D2D (device-to-device) technology. This technology allows you to reduce the load on the core of the network due to the use of a significant proportion of the traffic directly between devices and reduces the delay in providing services. Objective. The goal of the work is to create an optimal combined criterion for choosing effective traffic routes in a wireless network based on D2D technology. Method. Many modern works are devoted to the study of D2D technology, but they are not exhaustive in the study of routing in such networks. It is objective enough to study networks built on the basis of the interaction of devices with each other using D2D technology, since such interactions have proven to be effective technologies. This, in turn, involves the development of appropriate routing methods in networks using D2D technology, especially taking into account the property of over-density 5G networks. The paper proposes a criterion for selecting routes, taking into account interference within the channels forming the network nodes. This criterion combines the choice of routes according to the length criteria and the criterion of maximum throughput. Results. A developed combined criterion for selecting traffic routing in a wireless network that uses D2D technology. The results of the study are shown in graphic data. Conclusions. The experiments confirmed the efficiency and effectiveness of the developed method and allow us to recommend this method for practical use as a result of route selection, taking into account those network properties that are more likely to affect the quality of the route.
V. N. Gorev, A. Yu. Gusev, V. I. Korniienko
Radio Electronics, Computer Science, Control, Volume 1, pp 29-35; doi:10.15588/1607-3274-2021-1-3

Abstract:
Context. We consider the Kolmogorov-Wiener filter for forecasting of telecommunication traffic in the framework of a continuous fractional Gaussian noise model. Objective. The aim of the work is to obtain the filter weight function as an approximate solution of the corresponding WienerHopf integral equation. Also the aim of the work is to show the convergence of the proposed method of solution of the corresponding equation. Method. The Wiener-Hopf integral equation for the filter weight function is a Fredholm integral equation of the first kind. We use the truncated polynomial expansion method in order to obtain an approximate solution of the corresponding equation. A set of Chebyshev polynomials of the first kind is used. Results. We obtained approximate solutions for the Kolmogorov-Wiener filter weight function for forecasting of continuous fractional Gaussian noise. The solutions are obtained in the approximations of different number of polynomials; the results are obtained up to the nineteen-polynomial approximation. It is shown that the proposed method is convergent for the problem under consideration, i.e. the accuracy of the coincidence of the left-hand and right-hand sides of the integral equation increases with the number of polynomials. Such convergence takes place due to the fact that the correlation function of continuous fractional Gaussian noise, which is the kernel of the corresponding integral equation, is a positively-defined function. Conclusions. The Kolmogorov-Wiener filter weight function for forecasting of continuous fractional Gaussian noise is obtained as an approximate solution of the corresponding Fredholm integral equation of the first kind. The proposed truncated polynomial expansion method is convergent for the problem under consideration. As is known, one of the simplest telecommunication traffic models is the model of continuous fractional Gaussian noise, so the results of the paper may be useful for telecommunication traffic forecast.
O.а. Глотка
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 13-21; doi:10.15588/1607-6885-2020-2-2

Abstract:
Objective. To study the specifics of the distribution of alloying elements in the carbides of the multicomponent system Ni-5Cr-9Co-6Al-1Ti-11.7W-1.1Mo-1.6Nb-0.15C by directional crystallization, using the calculated method of CALPHAD prediction. Research methods. To find regularities and calculate the distribution of alloying elements in the alloy, the latest CALPHAD method was chosen, and modeling of thermodynamic processes of phase crystallization was performed. The obtained results. The results of thermodynamic calculations of the chemical composition of carbides are given in the form of mathematical dependences. The equation of the influence of alloying elements on the dissolution (release) temperature of carbides is obtained. It is shown that the obtained dependences are closely correlated with the thermodynamic processes occurring in the system. Scientific novelty. It is shown that with increasing total concentration of carbide-forming elements, the chemical composition of carbides becomes more complicated. The titanium content of more than 2% leads to an increase in the temperature of the carbide liquidus, and at 4.5 % topologically densely packed phases is formed. When the concentration of molybdenum in the alloy is more than 4%, the probability of precipitating topologically close-packed phases in the structure increases markedly, which negatively affects the mechanical properties and heat resistance. Practical value. Based on an integrated approach for multicomponent heat-resistant nickel-based alloys, new regression models were obtained that allow adequately predict the chemical composition of carbides by the chemical composition of the alloy, which allowed to solve the problem of calculated prediction of carbide composition by chemical composition of the alloy.
G. Snizhnoi, V. Ol’Shanetskii
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 88-89; doi:10.15588/1607-6885-2020-2-12

Abstract:
Термодинамічні аспекти протилежного впливу Mn і Ni на магнітний стан аустеніту
A.а. Ленок, В.д. Обдул, O. Vinovets
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 50-56; doi:10.15588/1607-6885-2020-2-7

Abstract:
Purpose of work. Investigation of the features of the technological process of manufacturing curvilinear sections of the pipeline – steeply curved bends. Research methods. Three-dimensional modeling of a design of equipment and a finished product; experimental studies of the technology of manufacturing steeply curved bends by pushing through a curved hole of the assembly matrix without using fillers; estimation of deformation by the method of dividing grids. Obtained results. Literary sources are analyzed and the main problems arising in the manufacture of steeply curved bends for each method are identified. To study the features of the manufacturing technology, a three-dimen­sional model of the assembly matrix was modeled using the investigated method, the design, dimensions and material of the tooling were selected. Equipment was made. Sizes and material of pipe billets were selected. The operations of the technology for the manufacture of steeply curved bends by pushing through a curved hole of the assembly matrix without the use of fillers were determined. Experimental studies of the technology have been carried out. For this, the manufactured stamp was installed on a PG-100A hydraulic press. Pipe billets were placed in a guide sleeve, which was screwed to the assembly die when the press rod was placed in the upper position. The punch pushed the pipe billet along the curved hole of the assembly matrix while moving the rod down. Upon completion of the pushing process, the press rod was in the upper position. For unimpeded removal of the finished product, the guide sleeve was removed, the matrix was unscrewed and removed from the clamps. Several samples were obtained, the presence of defects and problems that arose during the formation of steeply curved bends were revealed. To assess the deformation, the method of dividing grids was used. Scientific novelty. The method of manufacturing steeply curved bends by pushing an assembly matrix through a curved hole was further developed. The peculiarity of the investigated technology - rejection of the use of expensive filler or rigid mandrels, reduction of technological operations and time for manufacturing a unit of a finished product. As a result of the study, dangerous zones of pipe billets in the process of manufacturing steeply curved bends were identified: the place of bending (crushing, corrugation, rupture) and the ends of the finished product at the exit (ovalization, distortion, breaks). Practical value. To prevent the occurrence of dangerous zones during deformation of pipe billets and improve the quality of the finished products obtained, requirements were formulated for the design of the working elements of the developed stamp, the choice of optimal modes of the shaping process, the material and the optimal shape of the pipe billet.
O. Mityaev
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 89-93; doi:10.15588/1607-6885-2020-2-13

Abstract:
СМС-композити: характеристики, сучасний стан та перспективи виробництва, застосування
I. Zolotarevskii
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 22-29; doi:10.15588/1607-6885-2020-2-3

Abstract:
Purpose of work. To ascertain the causes of the abnormally large displacement of the martensitic point in steels and iron alloys in strong pulsed magnetic fields at low temperatures. Research methods. Generalization of experimental and theoretical investigations of the strong magnetic field influence on the martensitic transformation in steels and iron alloys, taking into account the magnetic state of austenite. The obtained results. The distributions of the martensitic point displacement ΔMS from the content of the main component - iron and the temperature of the martensitic γ → α- transformation beginning (martensitic point MS) in different experiments are obtained. It is shown that the obtained temperature dependence ΔMS(MS) in a strong magnetic field at low temperatures decomposes into two components, one of which correlates with the generalized Clapeyron-Clausius equations, and the other is opposite to it. In addition, it was found that steels and alloys with intense γ → α- transformation in a magnetic field contain at least 72.5% iron (wt), which at low temperatures in the fcc structure is antiferromagnetic. Scientific novelty. The anomalous temperature dependence of the distribution ΔMS(MS) in a strong magnetic field is explained on the basis of quantum representations of the magnetic interaction of atoms in the Fe-Ni system. This effect is associated with a number of other invar effects, in particular, with an abnormally large spontaneous and forced magnetostriction, a strong dependence of the resulting exchange integral on the interatomic distance. The point of view according to which in these alloys in a magnetic field γ → α- transformation occurs by the type of “magnetic first kind phase transformation” is substantiated. It is assumed that the nucleation of the martensitic phase in a magnetic field occurs in (at) local regions of γ- phase with disoriented atomic magnetic moments (with high compression and increased forced magnetostriction). Practical value. The information obtained in this work provides grounds for explaining the kinetic features of the transformation of austenite into martensite in steels and iron alloys.
L. Gulyaeva, T.в. Татарчук
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 93-95; doi:10.15588/1607-6885-2020-2-14

Abstract:
Роль фізики у фаховій підготовці майбутніх інженерів
С.м. Попов, S. Shumykin, Н. Laptieva
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 82-87; doi:10.15588/1607-6885-2020-2-11

Abstract:
Purpose. To establish mathematical models for the adaptation of materials under conditions of activation of a metastable structural-phase state of quasi-dissipative tribosystems. Determination and substantiation of factors for planning an active experiment due to which it is possible to create mathematical models of stable forecasts for increasing the wear resistance of materials. Research methods. When conducting the experiments, a priori data were used in combination with our own scientific developments of mathematical models of the dependences of the influence of the chemical composition of alloys during manual and automatic electric arc surfacing on the physical and mechanical properties of the surface layer of the material, which is destroyed under tribosystem conditions. It was decided to use mathematical planning of research on the basis of an active experiment with the creation of models for the numerical description of the mathematical expectation in the form of regression equations. Obtained results. On the basis of theoretical and practical scientific research with planning a passive and active experiment, a set of relevant knowledge has been obtained, which makes it possible to determine the main criterion requirements for the sensitivity of deposited steels and alloys to adaptation under the action of external mechanical and energy influences and allows to mathematically describe the characteristics of the alloy and provide a numeri­cal estimate of the correlation parameters among themselves. On the basis of the theory of scientific mathematical planning of the experiment, a set of corresponding experiments was carried out, which made it possible to build spatial graphic models. Scientific novelty. For the first time, theoretical and practical scientific research is presented with the reproduction of a systemic multivariate analysis of the parameters of mathematical models and processes leading to the martensitic ( γ → α ) transformation and determines the substantiation of the chemical composition of the deposited materials to increase fracture resistance under conditions of quasi-dissipative and dissipative tribosystems. Practical meaning. The obtained results of the above studies allow, within the framework of technical and technological accuracy, which is necessary within the framework of practical engineering forecasts, to determine the physical and mechanical properties of wear-resistant deposited alloys under conditions of quasi-dissipative and dissipative tribosystems.
S. Kiyko
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 71-81; doi:10.15588/1607-6885-2020-2-10

Abstract:
Purpose. To build a model of project selection for the portfolio in accordance with the energy strategy of the metallurgical enterprise. The urgency of solving these issues for the metallurgical industry of Ukraine is caused by the need to improve the economic stability of enterprises, increase the competitiveness of products and reduce dependence on energy suppliers. Methods. Methods of program and portfolio management, system approach, models and methods of strategic management in the field of project management and mathematical apparatus of set theory are used in formalizing the model of forming a portfolio of energy saving projects at a metallurgical enterprise. Results. The analysis of the general problem of portfolio management of energy saving projects at metallurgical enterprises is performed. The main stages of formation and implementation of the portfolio of energy saving projects of the metallurgical enterprise are considered in detail. A formalized mathematical model for the selection of energy saving projects at a metallurgical enterprise for the portfolio has been developed. With the help of the proposed approach and models, a portfolio of projects of the metallurgical enterprise PJSC “Dniprospetsstal” was formed, which included promising projects for implementation in accordance with the energy strategy. Scientific novelty. A model of project portfolio formation in accordance with the energy efficiency strategy of a metallurgical enterprise has been developed, which comprehensively takes into account the current state of the enterprise and its future strategic directions, resource and financial support of energy saving projects and risks of adverse events. Practical meaning. The use of this model allows consistent analysis of portfolio projects in order to identify opportunities for their implementation at the metallurgical enterprise, to coordinate project implementation plans and plans at different levels of planning, to select the most promising projects for implementation in accordance with the energy strategy.
В.м. Плескач, V. Ol’Shanetskii
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 45-49; doi:10.15588/1607-6885-2020-2-6

Abstract:
Purpose. Optimization of methods of design, calculation and use of slip bearings; elaboration of recommendations on the use of powder materials and lubricants for the production of slip bearings. Research methods. Analysis of existing calculations of slip bearings, of efficiency of the bearing under conditions of self-lubrication and features of using hydrodynamic lubrication theory for calculations of slip bearings in the presence of liquid lubrication. Results. The area of predominant application of slip bearings, their main elements are clarified and described; recommendations on the sizes of structural elements of bearings are given. The main types of slipping friction and their relationship with the bearing design and operating conditions are analyzed. The possible composition of powder materials for slip bearings, the interdependence of bearing porosity and the viscosity of the oil used to ensure the of its longevity is analyzed. Recommendations for the design of bearings in conditions of liquid friction are given. Generalized methodology for calculating the efficiency of slip bearings is proposed. Based on the theory of hydrodynamic lubrication, a method for calculating slip bearings for liquid lubrication conditions, which provides optimal operating conditions is proposed. Scientific novelty. Optimized selection of powder material and structure to improve lubrication conditions is proposed. The analysis of the influence of the chemical composition of the oil to ensure maximum adhesion of this oil with a bearing surface is resulted; the analysis of the influence of the chemical composition of the oil to ensure maximum adhesion of this oil with a bearing surface, as well as mathematical dependencies that make it possible to adjust the composition of the oil by adding specially selected microadditives is resulted. Generalized approaches to the method of calculation of powder slip bearings, which operating under different friction conditions are proposed. Practical value. Practical methods of designing and calculating slip bearings from powder materials are offered.
G. Slynko, V. Slynko
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 6-12; doi:10.15588/1607-6885-2020-2-1

Abstract:
Purpose. Improving the mechanical and operational properties of details of internal combustion engines by managing the structure formation of phosphorous cast irons. Research methods. Graphitized and bleached phosphorous cast irons with lamellar and globular graphite of laboratory and industrial melts, melted in electric induction furnaces with alloying modification and fractional casting into dry sand molds were investigated. Chemical composition, microstructure, physical and mechanical properties were determined using standard methods. Non-destructive quality control of engine parts, statistical analysis of experimental data and deterministic factor analysis of the influence of structural components on the properties of the cast irons were carried out according to the methods developed with the participation of the authors. Bench and road motor tests of optimal composition cast irons details were carried out in engines according to standard and factory methods in accordance with state standards. Obtained results. The general laws and principles of the formation of the microstructure of cast irons with lamellar and nodular graphite are determined depending on the degree of their alloying with phosphorus and the influence of the scale factor. It has been established that phosphide eutectic in an amount of up to 5.8 % is a strengthening structural component and increases strength, hardness, wear resistance, heat resistance, and machin-ability of phosphorous cast irons with blade tools. The negative effect of phosphide eutectic on plastic properties and cyclic fracture toughness is less significant than the effect of increasing amounts of ferrite, its grain size and graphite. Optimal chemical compositions and microstructures of phosphorous cast irons for internal combustion engines details are recommended. Scientific novelty. For the first time, a comprehensive system for managing the properties of phosphorous cast irons has been developed, including the analytical determination of the required characteristics of structural components and the technology for their production. Practical value. Methods and technologies for melting, alloying, modifying, heat treatment and surface hardening of phosphorous cast irons have been developed. They make it possible to provide the required level of mechanical and operational properties of internal combustion engines details.
S. Homeniuk, S. Grebenyuk, D. Gristchak
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 66-70; doi:10.15588/1607-6885-2020-2-9

Abstract:
The relevance. The aerospace domain requires studies of mathematical models of nonlinear dynamic structures with time-varying parameters. The aim of the work. To obtain an approximate analytical solution of nonlinear forced oscillations of the designed models with time-dependent parameters. The research methods. A hybrid approach based on perturbation methods, phase integrals, Galorkin orthogonalization criterion is used to obtain solutions. Results. Nonlocal investigation of nonlinear systems behavior is done using results of analytical and numerical methods and developed software. Despite the existence of sufficiently powerful numerical software systems, qualitative analysis of nonlinear systems with variable parameters requires improved mathematical models based on effective analytical, including approximate, solutions, which using numerical methods allow to provide a reliable analysis of the studied structures at the stage designing. An approximate solution in analytical form is obtained with constant coefficients that depend on the initial conditions. Conclusions. The approximate analytical results and direct numerical solutions of the basic equation were compared which showed a sufficient correlation of the obtained analytical solution. The proposed algorithm and program for visualization of a nonlinear dynamic process could be implemented in nonlinear dynamics problems of systems with time-dependent parameters.
В.I. Мазур, П.I. Лобода, Т. Soloviova, M. Vterkovskyi, Д.о. Ремiзов, О. Kovryzhko, L. Smolinskyi
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 30-36; doi:10.15588/1607-6885-2020-2-4

Abstract:
Purpose of work. To investigate the features of microscopic kinetics of peritectoid transformation in Fe-Mo system alloys in an isothermal mode. Experimental part. Microscopic analysis of samples on light (Jenaphot 2000, K. Zeiss) and scanning electron (REM 106I, Selmi) microscopes, X-ray spectral microanalysis of the component’s concentrations distribution between the phases, X-ray phase analysis (Rigaku Ultima IV diffractometer). Results. Microstructure changes, phase composition and crystal lattices parameters of the phase constituents of the powder alloy during sintering at 920 °C were investigated. Variation in the phase constituents mass fraction during 7 hours of the isothermal exposure is analyzed. The formation of anomalous diffusion porosity at the beginning of the process, the nonmonotonic change in the phase constituents fraction and formation of intermediate phases with an unstable component’s concentration are the main features of the microscopic kinetics. The sintering mechanism is proposed. Scientific novelty. A local peritectoid transformation existence at the Fe/Mo interface was established by analyzing the local diffusion flows of components atoms. This transformation occurs upon isothermal supply of Mo atoms with the formation of a cooperative peritectoid structural constituents according to the α- Fe + Mo → α + μ scheme with residual Mo crystals. Formulation of the problem. This work aims to clarify the phenomenological theory of peritectoid transformation during isothermal α-Fe grains enrichment with molybdenum by studying the features of microscopic kinetics in the Fe-Mo system alloys. Practical value. Peritectoid (α + μ) with branched phase соnstituents of cooperative genesis forms a developed system of local diffusion flows of Mo atoms in α -Fe. This increases the molybdenum peritectoid transformation rate at a relatively low sintering temperature for these alloys and reduces the energy consumption in the technological process.
Yu. Kravchuk, T.в. Татарчук
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 57-65; doi:10.15588/1607-6885-2020-2-8

Abstract:
The purpose of the work. Statistical and experimental analysis of coating methods on the turbine nozzle apparatus to increase the temperature regime. Research methods. Calculation method of finite elements, experimental. The results obtained. Studies have shown that the use of thermally protective coatings TZP thickness of 250 мm with a thermal conductivity of 1 W / mK on the two steps of the turbine can implement one of two possibilities: - at constant operating temperature of the blade material to increase the temperature of the gas in front of the turbine by about 100 °C, which will increase efficiency and fuel savings by more than 13 %;- without changing the temperature of the gas in front of the turbine - to increase the durability of the blades by about 4 times, due to a decrease in their operating temperature. The analysis of two methods of drawing TZP was carried out, in the work the estimation of a temperature condition of the nozzle device (CA) of the turbine of a high pressure of the engine, decrease in its temperature due to drawing TZP and increase of its resource is carried out. The problem was solved by applying TZP on the blades of the nozzle apparatus. The analysis of two methods of drawing TZP was carried out, the estimation of a temperature condition of the nozzle device (CA) of the turbine of high pressure of the engine, decrease in its temperature due to drawing TZP and increase of its resource is carried out. Scientific novelty. The problem of creating efficient, economical and reliable gas turbines is the most difficult among the many problems that arise in the development of gas turbine construction. Important elements of turbines are working and nozzle blades, the material and design of which determine the allowable gas temperature in front of the turbine and thus directly affect the technical and economic performance of the gas turbine engine. Practical value. The obtained results are important for the further development of aircraft engine construction, due to the application of TZP achieved an increase in the resource of CA from 40,000 hours to 67,000 hours.
V. Klochikhin, С.м. Данилов, N. Lysenko, V. Naumyk
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering pp 37-44; doi:10.15588/1607-6885-2020-2-5

Abstract:
Purpose. To study the effect of modification by the titanium carbonitride Ti(C, N) ultrafine particles additives in the form of powder and briquettes on the structure and physical-mechanical properties of the ЖС3ДК-ВІ alloy used for the manufacture of aircraft engine turbines cast rotor blades. Research methods. Preliminary high-temperature treatment of the melt was carried out on a VIP-10 installation. On the UPPF-3M installation with the alkaline melting pot, the ЖС3ДК-ВІ alloy was modified with ultrafine particles of titanium carbonitride Ti(C,N) in an amount of 60...80 g in the form of briquettes or powder wrapped in nickel foil. The samples were subjected to homogenization at a temperature of 1210 °C with a holding time of 3.5 hours and air cooling. The chemical composition of investigated alloys was determined. The macrostructure was studied on plates ~ 4 mm thick after chemical etching. The microstructure was evaluated on microsections before and after etching in the Marble reagent. Microhardness, ultimate strength, elongation and contraction, impact strength were determined at room temperature. Long-term strength tests were carried out at 850 °C under a load of 350 MPa. The bending test of the blades was carried out on a manual screw press in accordance with GOST 14019-80. Results. The microstructure of Ti+TiCN briquettes has been studied by optical and electron microscopy. X-ray microanalysis of specimen fractures confirmed a fairly uniform distribution of titanium carbonitride in the volume of briquettes. The chemical composition, macro- and microstructure of the experimental alloy have been studied. A fracto-graphic study of the samples fracture structure was carried out. The modifying effect of titanium carbonitride ultrafine particles on the dendritic structure, distribution and change in the morphology of primary carbides, the number and distribution of carbonitride particles has been established. A comparative analysis of the mechanical and heat-resistant properties of the ЖС3ДК-ВІ alloy of standard composition and modified with ultradispersed Ti(C,N) particles has been carried out. Bending tests of turbine rotor blades were carried out. Scientific novelty. It is shown that the use of ultrafine titanium carbonitride powders for bulk modification of the heat-resistant nickel alloy ЖС3ДК-ВІ makes it possible to increase the mechanical and heat-resistant properties of the material. Increasing the amount of modifier promotes grain refinement. More stable properties and favorable structure are provided by melt modification with ultrafine Ti(C,N) particles in the form of briquettes. It was found that modification with powdered Ti(C,N) leads to a decrease in the impact toughness values due to the formation of boundary microporosity. Practical value. The technology of the heat-resistant nickel alloy ЖС3ДК-ВІ, used for the manufacture of cast rotor blades of gas turbine engines, modification with additives of titanium carbonitride Ti(C,N) ultrafine particles, providing an increased level of performance properties of finished products, has been developed.
V Grabovskii, O Lisitsa
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering; doi:10.15588/1607-6885-2021-1-13

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O Glotka, V Klochikhin, V Ol’Shanetskii
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering; doi:10.15588/1607-6885-2021-1-1

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S Popov, S Shumykin
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering; doi:10.15588/1607-6885-2021-1-7

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V Pleckach, V Ol'shanetskii
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering; doi:10.15588/1607-6885-2021-1-12

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T Tatarchuk
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering; doi:10.15588/1607-6885-2021-1-5

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V Mazur
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering; doi:10.15588/1607-6885-2021-1-6

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G Snizhnoi, V Ol’Shanetskii, V Sajhnev
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering; doi:10.15588/1607-6885-2021-1-3

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G Slynko, R Sukhonos, P Tsokotun, V Slynko, D Volodin
Innovative Materials and Technologies in Metallurgy and Mechanical Engineering; doi:10.15588/1607-6885-2021-1-10

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, O.V. Bialobrzheskyi
Electrical Engineering and Power Engineering pp 40-50; doi:10.15588/1607-6761-2020-2-5

Abstract:
Purpose. The purpose of the article is to investigate the modes of operation of a three-phase active power filter in the composition of an autonomous electrical network when connected to a network of three-phase nonlinear load of different spectral character.Methodology. For the research, the provisions of the pq-theory of power, the theory of electrical circuits, the theory of automatic control, mathematical modeling in the Matlab package were used.Findings. The graphs and spectral composition of the mains voltage and load current have been obtained, which makes it possible to evaluate the effectiveness of using a power active filter in the filtration mode as part of an autonomous electrical network, which is a synchronous generator. Originality. The efficiency of the parallel operation of a power active filter in the filtration mode with a synchronous generator at an abruptly variable nonlinear load is proved.Practical value. The use of the proposed technique will make it possible to create a three-phase power active filter for its use in autonomous electrical networks, represented by a synchronous generator with automatic regulation of the excitation voltage.
V.V. Zіnovkin, O.V. Blyzniakov
Electrical Engineering and Power Engineering pp 17-23; doi:10.15588/1607-6761-2020-2-2

Abstract:
Purpose. To establish quantitative indicators of the influence of non-sinusoidal loads on the parameters and operability of contacts of voltage control devices of transformers of power-consuming electrical installationsMethodology. In our research, we used the probabilistic-statistical methods to analyze the experimental findings. Experimental studies were carried out applying advanced software-based methods for processing, systematizing and visualizing the findings derived.Findings. The analysis of the accident rate of transformers for power-consuming technological installations showed that adjustable transformers, in particular, on-load tap-changers, are in many cases the cause of failure in the operation of electrical installations. On the example of a switching device of the RNOA-110/1250 type, it was experimentally established that the non-sinusoidality of the current caused by abruptly alternating loads, in combination with an increase in the number of switchings, leads to an increase in the contact resistance, which significantly reduces the reliability and serviceability of contacts. Originality. The dependence of the transient resistance of the contacts of the voltage control device under the load of the transformer on the degree of non-sinusoidality of the load current is obtained. Practical value. The results of the work can be used in the development of new designs of on-load tap-changers for special purpose operation under conditions of load fluctuations. In particular, the work is aimed to increase the reliability of on-load tap changers contact systems, as well as in the study of the operating conditions of network and furnace transformers in power supply systems of energy-intensive technological installations.
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