2021

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1905 рік і Люботинська республіка в історії Харківського технологічного інституту (ХТІ)
(Національний технічний університет "Харківський політехнічний інститут", 2021) Павлова, Галина Вікторівна; Главчева, Юлія Миколаївна
Стаття присвячена діяльності видатних особистостей України та їх ролі у розбудові нашої держави; розкрито роль студентської молоді Харківського технологічного інституту у подіях 1905 року під час створення Люботинської республіки; доведено, що у Харківському технологічному інституті навчалися члени багатьох політичних партій та організацій – Української соціал-демократичної партії, Есерівської групи Південної партії соціал-революціонерів (Українська партія соціалістів-революціонерів), Польської соціалістичної партії, партії народних соціалістів, «Поалей Ціон» та ін., які брали активну участь у подіях кінця ХІХ ст. – початку ХХ ст.; на підставі газетних хронік описано події загального залізничного страйку у Люботині та наслідки, спричинені ними. У статті також наведено біографічні дані Костянтина Кірсти, студента Харківського технологічного інституту, учасника Першої світової війни, під керівництвом якого було збудовано стратегічно важливі два мости через річки Південний Буг та Інгул; засновника "Організаційного комітету з об'єднання всіх професійних робочих спілок м. Києва" та друкованого органу "Шлях робітника", чиї профспілки з'явилися у металістів, трамвайників, деревообробників, працівників водного господарства, харчовиків, людини, яка вважала, що запорука розвитку економіки – "відновлення приватної власності, примирення працівника та капіталіста, підвищення продуктивності праці"; доведено, що історія професійних спілок періоду громадянської війни в Україні, Кірстивського руху чекає правдивого, неупередженого та об'єктивного дослідження, яке має базуватися не лише на радянських партійних друкованих виданнях, а й на архівних матеріалах та достовірних першоджерелах.
25 років факультету "Соціально-гуманітарних технологій"
(Національний технічний університет "Харківський політехнічний інститут", 2021) б/а
Acid treatments quality improving analysis through new working agents usage
(Національний технічний університет "Харківський політехнічний інститут", 2021) Bukhkalo, Svetlana Ivanovna; Ivanytska, Iryna Oleksandrivna; Aheicheva, Oleksandra Oleksandrivna; Zezekalo, Ivan Havrylovych
Decrease in permeability that occurs during the construction of the well and operation are analyzed. The reasons for the decrease in the permeability of the bottom-hole zone in the reservoir rocks that occur in the process of drilling, cementing, reopening and development of wells are determined. The basic principles of acid treatment for intensification of hydrocarbon raw material extraction of sealed productive strata in the process of their drilling are investigated. The solution for acid treatment is given. Specialized products for stimulation are considered. Acid treatments quality increasing through new working agent’s usage and improving the technology analysis is performed: the scientific substantiation of the program realization algorithm of possible influence for concrete geological and physical conditions of a well is presented; systems of geological and technological factors influencing the filtration properties of reservoirs are identified and analyzed; identifying features of development and adaptation types of chemical compositions for specific conditions of the formation; the possibility of conducting experimental research on the development and adaptation the chemical compositions and technologies of influence in the processes of increasing productivity and silencing of wells in relation to specific geological and physical conditions is determined.
Algorithmic support for multicriteria assessment of retail information systems
(Національний технічний університет "Харківський політехнічний інститут", 2021) Bieliaiev, Oleksandr Ihorovych; Liutenko, Iryna Victorivna; Stratiienko, Nataliia Kostiantunivna
This article is devoted to the issues of assessing the effectiveness of information systems for enterprises engaged in retail trade in consumer goods. This article describes the tasks that the retail FMCG trade, as well as the functions of the retail trade, solve. The features of the subject area were considered, which will form the basis for the formation of scales for assessing the effectiveness of information systems. The priorities, tasks, and features of the business model of enterprises engaged in retail trade in consumer goods, depending on the market segment they occupy. Various types of corporate information systems that can be used in retail trade are considered. The analysis of the subject area made it possible not on ly to determine important metrics for assessing the effectiveness of information systems but also to determine the priority of the requirements for the availability of certain functionality in the information system from each business segment, large, medium and small. Also, the existing standards in the subject areas of software development and enterprise organization were considered. This article proposes a methodology for evaluating information systems for enterprises engaged in consumer goods retail trade that belong to different market segments. The proposed methodology is based on the approach of multi-criteria expert assessment. An example of linguistic variables for one of the questions of the questionnaire for experts is given. The order of operation of the expert system is also presented in the form of an activity diagram. The developed expert information system can be monetized by providing referral links to the products of companies supplying information systems for retail. In the future, it is planned to add the ability for qualified experts to select combination of metrics for assessment, as well as change the assessment scale to increase accuracy.
Allocation of steady-state areas of total electrical load schedules of 10/0.4 kV transformer substations located in residential areas
(Національний технічний університет "Харківський політехнічний інститут", 2021) Dovgalyuk, Oksana; Shcherbak, Iryna; Kovalova, Yuliia; Korobka, Volodymyr
Improving the efficiency of regulating the parameters of distribution network modes is an actual task for the energy sector, requiring a detailed analysis of the nature of the total electrical load graphs of 10/0.4 kV transformer substations. The complexity of the problem in consideration is due to the fact that the load variation of transformer substations 10/0.4 kV in residential areas occurs randomly, due to the significant number, wide range and probabilistic nature of the operating modes ofconnected consumers, and the lack of deterministic links between consumers of electricity. The investigated function of total load of transformer substations 10/0.4 kV on a daily interval is non-stationary, in this connection there was a necessity of allocation of stationarity areas for adjusting the process of regulation of parameters of electrical network modes. In order to solve this problem, total load graphs for 10/0.4 kV transformer substations located in a residential area were constructed based on experimental measurements of active and reactive loads. The use of these dependencies made it possible to analyse the distribution law for the active and reactive power of the total load of 10/0.4 kV transformer substations, which change in time is stochastic characterised. The use of probabilistic-statistical modelling was justified to reliably describe the load variation process of 10/0.4 kV transformer substations. The hypothesis of a normal law distribution of the functions under consideration was confirmed and parametric tests were performed. Fisher's F-criterion was used to confirm the hypothesis of variance constancy, and Student's t-criterion was used to confirm the hypothesis of mathematical expectation constancy. Using the fact of constancy of dispersions and expectations of investigated mode parameters, autocorrelation coefficients of investigated random functions were determined and autocorrelation function graphs were plotted. In order to approximate the functions under investigation, the autocorrelation function coefficients were determined using the least-squares method, and an analysis of the attenuation of the autocorrelation function was carried out. The calculations carried out have highlighted the areas of stationarity on the total load curves of the 10/0.4 kV transformer substations. These stationarity plots can be used for further modelling of load graphs and the formation of control actions to adjust the load of consumer regulators in order to equalise the overall electrical load graph, as well as for voltage regulation facilities, which will contribute to the required modes of operation of the electricity distribution networks.
Analysis of factors influencing the intensity of transformer oil ageing in long-term operation
(Національний технічний університет "Харківський політехнічний інститут", 2021) Ponomarenko, Serhii
The results of the analysis of influence of operational factors and peculiarities of transformer design on intensity of oxidative reactions of transformer oils in the tanks of 110 kV high-voltage power transformers are presented. As a result of two-way analysis of variance it was found that with increasing operating time there is a statistically significant increase in the value of the organic acid content in the oil. At the same time the rate of increase in the organic acids content in the transformer oil, operated under different conditions, significantly differs, which indicates a significant influence of operating conditions on the intensity of oxidative reactions. The results of two-way analysis of variance also show that the effects of changes in factor levels are not additive, that is, the effect of a change in the level of influence of one factor leads to a change in the effect of the level of influence of another. In other words, the process of oil oxidation is cumulative and a certain level of organic acids in the oil can be achieved either over a longer period of operation, but with relatively 'light' operating conditions, or over a shorter period of time, but with more 'heavy' operating conditions. In order to determine the factors most affecting the intensity of oxidative reactions, an analysis of the quality of filled oil, operating time, the influence of the region, the influence of the type and nominal characteristics of transformers on 6 data sets with identical rates of oxidative rea ctions was carried out. The results of the analysis show that the intensity of oxidation reactions is strongly influenced by the operating time, the transformer loa ding factors, the consumer composition (region of Ukraine) as well as the type and quality of oils. At the same time, factors such as rated capacity, type of transformer, number of windings, and the value of rated voltage on the medium and low voltage windings do not influence the intensity of oxidation of oils. The results obtained allow the correction of the maximum permissible values of oil acidity, taking into account the factors affecting the intensity of oxidation of oils.
Application of elements of studying the function of one variable when solving chemical problems
(Національний технічний університет "Харківський політехнічний інститут", 2021) Prishchenko, Olga Petrivna; Chernogor, Tetyana Timofiyivna
In the article some problems are examined with chemical maintenance, for the decision of that the elements of research of function one variable are used. A course of higher mathematics is basis of physical and mathematical training of specialists-chemists of university profile. The primary purpose of teaching of educational discipline "Higher mathematics" is preparation of students to using of modern mathematical vehicle as an effective instrument for the decision of scientific and practical problems in area of chemical and contiguous disciplines. Mathematics for chemical engineers is primarily a useful tool for solving many chemical engineering problems and tasks. It is difficult to find a branch of mathematics that is not at all used to solve these problems at all stages of their analysis. As a result of study of higher mathematics a student must know the methods of mathematical analysis in application to one function and a few real variables. Many chemical phenomena are described through functional dependence. At the study of chemical processes, it is necessary to use research elements functions of one variable, the exposure of properties of function, characterizing her different internals, behaves to that. In practical classes in higher mathematics, when considering the topic 'Derivative and its applications', it is often necessary to solve problems of a general nature. But for students of chemical specialties, tasks that are directly related to their profession are of greater interest. Thus, considering tasks similar to those given in this article, we will increase the interest and motivation of future specialists to study this material.
Application of the correlation theory of inhomogeneous random fields to the study of the statistically inhomogeneous screen model
(Національний технічний університет "Харківський політехнічний інститут", 2021) Cheremskaya, Nadezhda Valentinovna
The article considers the problem of finding a field created by a system of fluctuating sources on the screen, which is characterized by a correlation function, where   1 2, AA K r r  the correlation function is separable. This image corresponds to a random field on the screen, which is the sum of a separable field and a heterogeneous random field of the first rank, which significantly changes the correlation radius at a distance l. The model studied in this paper does not assume uncorrelated sources and coincidence of laws of intensity change and therefore corresponds to a system of sources with significantly different intensities and laws of their change in the direction of wave propagation in the transverse plane. The correlation function of the sources be not assumed to be separable and the field distribution on the screen is an inhomogeneous random field of the first rank or is the sum of a separable field and a statistically inhomogeneous field of the first rank. To find a solution in the approximation of a parabolic equation, a method of immersion in the corresponding Hilbert space is proposed, which allows one to quickly and efficiently find the statistical characteristics of the solution. As an example, the influence of statistical inhomogeneity on the intensity function of a luminous screen, which has the shape of a round disk, is considered. An off-screen correlation function is obtained, which contains information on the size and nature of inhomogeneities of emitting sources on a luminous screen. A numerical analysis of the representation for the correlation function is carried out in the case when the statistical heterogeneous of the environmen is generated by the presence of a continuous spectrum or a spectrum at zero. The article obtains approximate calculation formulas for the average temperature field and its dispersion, which take into account fluctuation processes in the calculation of thermal regimes of solar panels, which allow to make appropriate corrections in theoretical calculations.
An approach to analysis of ArchiMate application architecture models using the software coupling metric
(Національний технічний університет "Харківський політехнічний інститут", 2021) Kopp, Andrii Mykhailovych; Orlovskyi, Dmytro Leonidovych; Ersoyleyen, Dorukhan
Applications architecture is the baseline of any organizational activity, which main goal is to provide the executional environment for business processes in order to deliver products or services to satisfy customer needs and generate revenue. Nowadays, large software engineering projects always begin with the architecture design phase, despite the waterfall or agile methodology is used by a software development team. Applications architecture design is the most important and, at the same time, error-prone stage of the whole software engineering project. It is well-known that design shortcomings made on the design phase may increase drastically to testing and maintenance phases. Further costs to defects fixing may be hundred times higher in the later project stages in compare to the design stage on which applications architecture is defined. Common system design solutions, which were proven on practice and used in many projects, are known as architectural patterns. Software architecture patterns are considered as building block for system implementation. The most popular and efficient way to share architectural patterns are graphical models that used as any other blueprints of engineering solutions. Applications architecture models are built to represent system design, whereas, such models are already based on certain patterns as the industry best practices. Hence, in this paper we consider a relevant problem of applications architecture models analysis, which relevance is defined by those fact that designed blueprints of information systems and other software solutions should be carefully checked for all presumable inefficiencies in order to avoid extra efforts and related costs for defects fixing in the later project stages. It is proposed to use ArchiMate enterprise architecture modeling language, since it can be used not only to represent applications architecture, but is connection to business and technology layers. In order to evaluate applications architecture models, respective ArchiMate metamodel is considered and represented as labeled directed graph, and coupling software metric is selected for analysis. Sample calculations are demonstrated, obtained results are discussed, conclusion and future work directions are formulated.
Basic bases of calculations and optimization of NPP power unit equipment parameters methods of mathematical modelling
(Національний технічний університет "Харківський політехнічний інститут", 2021) Yefimov, Olexander Vyacheslavovych; Ilchenko, Boris Samuilovich; Tiutiunyk, Larysa Ivanivna; Harkusha, Tetyana Anatoliivna; Yesipenko, Tetyana Oleksiivna; Motovilnik, Anastasiia Vadimovna
The materials of the article consider the optimization of certain parameters and characteristics of the equipment of NPP power units, which are closely related to the processes of their design and construction. Modern NPP power units are complex technical systems. They include a set of interconnected equipment for different technological purposes, which ensures the performance of power units of a complex function of electricity production and heat of the specified quality and according to a given load schedule. Complete mathematical models of the functional state of steam turbine power units are characterized by a large number of nonlinear connections and contain implicit functions. This complicates their widespread use to solve problems of systematic analysis of the quality of operation of power units. The aim of the work is to analyze the basic theoretical foundations, methods and approaches to the calculation and optimization of the parameters of the equipment of NPP power units by methods of mathematical modeling. The solution of the problem of optimization of NPP power unit parameters includes the following stages: selection of optimality criteria (objective functions); development of a system of interconnected mathematical models in accordance with the required hierarchical level of optimization research; selection of computational methods and optimization algorithms. Taking into account the above methodological provisions and approaches increases the efficiency of mathematical modeling to solve problems of calculations and optimization of NPP power unit parameters.
Biometric method of personality authentication based on the eye tracking data
(Національний технічний університет "Харківський політехнічний інститут", 2021) Pavlenko, V. D.; Shamanina, T. V.; Chori, V. V.
A new method of biometric identification of a computer user is proposed based on the Volterra model and eye tracking data in dynamics (eye tracking technology). The nstrumental computational and software tools for constructing a nonparametric nonlinear dynamic model (Volterra model) of the human oculo-motor system have been developed on the basis of data from experimental studies "input-output" using innovative eye tracking technology. The obtained multidimensional transition functions are used to construct a biometric identification system for individuals.
Building a classifier in the personality recognition system based on eye tracking data
(Національний технічний університет "Харківський політехнічний інститут", 2021) Chori, V. V.; Shamanina, T. V.; Pavlenko, V. D.
The article proposes a new method of biometric identification of computer systems users, based on the determination of the integral Volterra model of the human oculo-motor system (OMS) according to experimental research "input-output" using innovative eye tracking technology. With the help of the Tobii Pro TX300 eye tracker, the data of OMC responses to test visual stimuli were obtained, displayed as bright dots on the computer screen at different distances from the start position in the "horizontal" direction. Based on the data obtained, the transition functions of the first, second and third orders of the OMS for two people were determined. To construct a personality classifier, the informativeness of the proposed heuristic features, determined on the basis of the transition functions in terms of the probability of correct recognition (PCR), is investigated. Pairs of features are established that are resistant to computational errors and have a high PCR value - in the range 0.92 - 0.97.
Calculation of the spatial flow in the francis high-head turbine using the CFD software package
(Національний технічний університет "Харківський політехнічний інститут", 2021) Krupa, Y. S.
At present, the development of software packages for calculating computational fluid dynamics problems has reached a high level of efficiency, accuracy and flexibility, with their help it is possible to solve the most diverse and complex problems. All modern software packages for computational fluid dynamics solve the problems of continuum mechanics using models based on the Navier-Stokes equations. These models are based on three conservation equations: conservation of mass, conservation of momentum and conservation of energy. A numerical simulation of the spatial flow of a high-head radial-axial hydraulic turbine Fr 310 was carried out for two variants of the flow path – with an runner with 15 blades (modification 1) and with 17 blades (modification 2), using the OpenFOAM software package. The OpenFOAM software package is one of the most used products designed to solve fluid dynamics problems and is distributed under a free GPL license (General Purpose License). The process of solving the set hydrodynamic problems using the CFD (Computational fluid dynamics) software package includes the following stages: creating a three-dimensional model of the object under consideration using a computer-aided design system; construction of a computational grid with the required parameters; selection of a mathematical model that most accurately describes the working process in the flow parts of hydraulic machines; selection of a suitable turbulence model; setting boundary conditions. A visualization of the results of a numerical study of two modifications of the Fr 310-V-100 hydraulic turbine is presented. A method for calculating hydraulic losses in the flow path of a hydraulic turbine is presented. The analysis of the results of numerical simulation was performed. This analysis showed that the modification of a hydraulic turbine with a runner with 15 blades is better in terms of efficiency than the modification with 17 blades. Comparison of the two modifications was carried out exceptionally by the values of the hydraulic efficiency of the hydraulic turbine.
CFD проектування пальника котла-утилізатора в системі освіти магістрів теплотехнічних спеціальностей
(Національний технічний університет "Харківський політехнічний інститут", 2021) Тарасов, Олександр Іванович; Литвиненко, Оксана Олексіївна; Михайлова, Ірина Олександрівна
Для розвитку навичок CFD проектування і розуміння процесів горіння у майбутніх фахівців теплофізичних спеціальностей проведено роботу моделюванню пальникового пристрою котла-утилізатора КУП-70-4,0-440, що працює у складі енергоблоку на ВАТ «Рубежанський картонно-тарний комбінат» в місті Рубіжне. В процесі побудови геометричної моделі враховано влив гідравлічного опору на потік колекторів, що подає і роздає. Для спрощення розрахунків задача виконувалась в двовимірній, вісісиметричній постановці. Аналізуючи розрахункові моделі горіння, обрано модель Non-Premixe Combustion, яка дозволила врахувати вхід палива і окислювача в зону реакції двома різними потоками, а також турбулентне дифузійне розповсюдження полум’я. Було досліджено шість варіантів моделей: перші три варіанти з жаровою трубою з суцільним диском, наступні три варіанти мали пальник з несуцільним диском. В результаті дослідження було обрано оптимальну форму пальника, що забезпечила найякісніший процес горіння, про що свідчить найвища температура факелу, і найменша температура біля диску. Проведене дослідження дає майбутнім магістрам навички моделювання процесів горіння в енергетичному обладнанні.
Comparative assessment of gaseous fuel emission
(Національний технічний університет "Харківський політехнічний інститут", 2021) Levytska, Olena Hryhoriivna; Voytenko, Yulia Vladimirovna; Orishechok, Anastasiia Oleksiivna
The work presents estimated comparative assessment of emissions release in combustion products during work of high–power steam boilers with the use of traditional fuel –natural gas and alternative fuels – blast–furnace and coke–oven gases generated in the process of technological cycle at iron and steel and coke–chemical enterprises. Calculation algorithm is shown and formulas for assessment of carbon content in exhaust gases are defined, conclusions on ecological efficiency of gaseous fuels are given. The purpose of the work was to evaluate the emissions of harmful substances generated during the combustion of natural, blast furnace and coke oven gases, justification of the calculation of carbon content of a given chemical composition and determine the optimal environmental impact of analogues of natural gas. The comparative estimation of pollutant emissions into atmospheric air during combustion of natural, coke oven and blast furnace gases revealed: –high sulfur dioxide emissions from combustion of blast furnace and coke oven gases due to the presence of sulfur compounds in the composition of these gases; –relatively high emissions of nitrogen compounds for natural and coke oven gases and relatively low emissions for blast furnace gas; – сarbon emissions are high for all types of fuels which have been considered, most carbon dioxide gets into the air when burning natural gas, least – when burning blast furnace gas; –significantly higher methane emissions are observed during the combustion of natural and coke oven gases, respectively, smaller – for blast–furnace gas combustion; –coke oven and natural gases are characterized by low mercury emissions. Comparative assessment of the calculated values of hazardous substances emissions in the combustion products in the process of combustion of natural, coke–oven and blast–furnace gases shows that even at lower working heat of combustion values the coke–oven and blast–furnace gases can compete with natural gas. For the first time, a comparative characterization of the emissions of harmful substances in the combustion of natural, coke oven and blast furnace gases is presented, and it is shown that the gases used in coke and metallurgical industries, which are used as analogues of natural, are logical to use, but require the installation of treatment systems. The paper defines a formula for calculating the carbon content in natural gas from the Urengoy–Uzhhorod gas pipeline. The provided calculations and the introduction of simplified formulas serve as an example for the calculation of emission factors and emissions in assessing the level of safety of existing equipment and can be used in the development of permit documents of enterprises that carry out emissions of harmful substances to the environment.
Computational and experimental method for estimating the residual life of gears based on vibration monitoring data
(Національний технічний університет "Харківський політехнічний інститут", 2021) Ishin, Nikolay Nikolaevich; Gavrylov, Sergii; Goman, Arkadiy; Skorokhodov, Andrey; Dakalo, Juriy
A computational and experimental method for estimating the residual life of gears in the inter-repair period is proposed. The method is based on the main provisions of the theory of vibration-pulse diagnostics of spur gears, developed at the OIM of the National Academy of Sciences of Belarus. The main performance criteria are the contact and bending endurance of the teeth. Accounting for changes in the value of the coefficient of internal dynamic load in the gearing during the operation of gears is carried out on the basis of vibration analysis during their vibration monitoring. The proposed method makes it possible to estimate the residual life of the gear mechanism at any stage of operation, providing the opportunity to organize the transition from planned preventive maintenance of machines to maintenance according to the actual condition.An example of estimating the residual life of a gear pair that limits the reliability of a two-row planetary gear motor-wheel of a heavy-duty dump truck is given.
Determine recommendation systems to search for books by preferences of web users
(Національний технічний університет "Харківський політехнічний інститут", 2021) Kozulia, Mariia Mykhailovna; Sushko, Vladislava Vladimirovna
Currently, the question of state, formation and development of the information source interaction system, the scientific interac tion and users' requests in certain fields of activity remains relevant under the conditions of the development of the use of Internet services. Recommendation systems are one of the types of artificial intelligence technologies for predicting parameters and capabilities. Due to the rapid increase in data on the Internet, it is becoming more difficult to find something really useful. And the recommendations offered by the service itself may not always correspond to the user's preferences. The relevance of the topic is to develop a personal recom mendation system for searching books, which will not only reduce time and amount of unnecessary information, but also meet the user's preferences based on the analysis of their assessments and be able to provide the necessary information at the right time. All this makes resources based on refer ral mechanisms attractive to the user. Such a system of recommendations will be of interest to producers and sellers of books, because it is an opportunity to provide personal recommendations to customers according to their preferences. The paper considers algorithms for providing recommender systems (collaborative and content filtering systems) and their disadvantages. Combinations of these algorithms using a hybrid algorithm are also described. It is proposed to use a method that combines several hybrids in one system and consists of two elements: switching and feature strengthening. This made it possible to avoid problems arising from the use of each of the algorithms separately. A literature web application was developed using Python using the Django and Bootstrap frameworks, as well as SQLite databases, and a system of recommendations was implemented to provide the most accurate suggestion. During the testing of the developed software, the wo rk of the literature service was checked, which calculates personal recommendations for users using the method of hybrid filtering. The recommendation system was tested successfully and showed high efficiency.
Development and comparative analysis of semi-supervised learning algorithms on a small amount of labeled data
(Національний технічний університет "Харківський політехнічний інститут", 2021) Yamkovyi, Klym
The paper is dedicated to the development and comparative experimental analysis of semi-supervised learning approaches based on a mix of unsupervised and supervised approaches for the classification of datasets with a small amount of labeled data, namely, identifying to which of a set of categories a new observation belongs using a training set of data containing observations whose category membership is known. Semi-supervised learning is an approach to machine learning that combines a small amount of labeled data with a large amount of unlabeled data during training. Unlabeled data, when used in combination with a small quantity of labeled data, can produce significant improvement in learning accuracy.The goal is semi-supervised methods development and analysis along with comparing their accuracy and robustness on different synthetics datasets. The proposed approach is based on the unsupervised K-medoids methods, also known as the Partitioning Around Medoid algorithm, however, unlike K-medoids the proposed algorithm first calculates medoids using only labeled data and next process unlabeled classes – assign labels of nearest medoid. Another proposed approach is the mix of the supervised method of K-nearest neighbor and unsupervised K-Means. Thus, the proposed learning algorithm uses information about both the nearest points and classes centers of mass. The methods have been implemented using Python programming language and experimentally investigated for solving classification problems using datasets with different distribution and spatial characteristics. Datasets were generated using the scikit-learn library. Was compared the developed approaches to find average accuracy on all these datasets. It was shown, that even small amounts of labeled data allow us to use semi-supervised learning, and proposed modifications ensure to improve accuracy and algorithm performance, which was demonstrated during experiments. And with the increase of available label information accuracy of the algorithms grows up. Thus, the developed algorithms are using a distance metric that considers available label information.
Development of technology and the potential of drinks with "anti-age" effect
(Національний технічний університет "Харківський політехнічний інститут", 2021) Kondratiuk, Nataliia Vyacheslavivna; Savchenko, Alina Mykolayivna; Cherniavska, Anna Yuriivna; Sytnik, Kateryna Igorivna
Modern trends in the creation of drinks provide for the use of various infusions, plant extracts, as well as vitamin and mineral complexes, organic acids and polysaccharides as part of their bases, which allows to ensure the normalization of physiological and metabolic processes in the human body and prevent a number of diseases and syndromes that lead to a decrease in working capacity. The main problems in the creation of various drinking forms are associated with the purification and preparation of water, the dissolution of components and their possible interaction with each other in the packaging unit during storage. Considering the above, it is relevant to create dry concentrates of health-improving drinks with long shelf life. The developed approach and technology is a promising form of drinks to improve the living standards of the population of Ukraine and other countries. The developed products will improve immunity, prevent a number of nutritional diseases, improve dietary intake during diet therapy and help restore micronutrient balance in the human body. It has been established that the physiological value of dry drinks according to the described production method is preserved in finished product forms (sticks with a metallized backing, sachets, sachets with a “zip-fastener” and a metallized inlay, plastic cans with a screw cap and with polymer backing as a control against preliminary opening) the entire recommended shelf life is from 12 to 24 months. The mixture is a convenient form for transportation and preparation. When diluted in liquid media (purified drinking water, mineral water, milk, fermented milk drinks, drinks based on plants, cereals, legumes, tea, coffee, cocoa), the specified functional properties are preserved and improved due to the activation of biologically active substances contained in the mixture and dilution media. The novelty of individual technological solutions and the indicated physiological and functional properties lies in the use of extracts of plants, fruits, berries, vegetables, as well as additionally introduced vitamins, mineral salts, amino acids, hydrolysates and isolates of plant proteins, natural bioenhancers and bioactiators with unique «anti-age» effects.
Diagnostics of the presence of a fatigue crack in the compressor blade using the spectrum of vibration amplitudes at the superharmonic resonance
(Національний технічний університет "Харківський політехнічний інститут", 2021) Savchenko, Kyrylo Valentynovych; Zinkovskyi, Anatolii Pavlovych; Onyshchenko, Yevheniia Oleksandrivna; Kruts, Vadym Oleksiiovych; Kabannyk, Serhii Mykolaiovych
In this study, the solution of the forced vibration response of a structural element with a fatigue crack was carried out using the finite element method to determine the influence of its presence on the flexural forced vibration behaviour of the compressor blade airfoil at the superharmonic resonance of the order 1/2. The blade airfoil with a low twisted angle was used as an object of investigation to perform the computational analysis. Its vibrations in the plane of minimum stiffness were excited by the kinematic displacement of root edge elements. The fatigue crack was modelled as a mathematical cut. Two locations of the crack were investigated – on the leading edge and convex side of the blade airfoil. The nonlinearity due to the intermittent contact of the crack surfaces, which is caused by the opening and closing of the crack during each vibration cycle, was taken into account by solving the contact problem. To quantify this kind of nonlinear dynamic behaviour, the vibration diagnostic parameter was defined as the displacement amplitude ratio of the dominant harmonics at the superharmonic resonance of the order 1/2. Based on the results of the calculations it has been found that regardless of the crack location, the ratio nature is the same for all vibration axes. However, with vibrations in the plane of minimum stiffness, the crack on the convex side of the airfoil has an opening mode propagation, which makes it possible to fix its location due to a sharp change in the ratio of the amplitudes of the dominant harmonics along the corresponding axis.