Eastern-European Journal of Enterprise Technologies
http://journals.uran.ua/eejet
<p><span lang="EN-US">Terminology used in the title of the "Eastern-European Journal of Enterprise Technologies" - "enterprise technologies" should be read as "industrial technologies". <strong>"Eastern-European Journal of Enterprise Technologies"</strong> publishes all those best ideas from the science, which can be introduced in the industry. Since, obtaining the high-quality, competitive industrial products is based on introducing high technologies from various independent spheres of scientific researches, but united by a common end result - a finished high-technology product. Among these scientific spheres, there are engineering, power engineering and energy saving, technologies of inorganic and organic substances and materials science, information technologies and control systems. Publishing scientific papers in these directions are the main development "vectors" of the "Eastern-European Journal of Enterprise Technologies". Since, these are those directions of scientific researches, the results of which can be directly used in modern industrial production: space and aircraft industry, instrument-making industry, mechanical engineering, power engineering, chemical industry and metallurgy.</span></p><p><span lang="EN-US">Therefore, the scientists, associated with modern production, have the opportunity to participate in technology transfer to industry, publishing the results of their applied scientific researches. Industrialists, in turn, can draw scientific and practical information from the journal - each in their direction:</span></p><ul><li>specialists in management and computer science - from volumes "Applied Information Technologies and Control Systems", "Mathematics and Cybernetics - Applied Aspects";</li><li>mechanical and design engineers - from the volume "Applied Mechanics";</li><li>production engineers - from volumes "Mechanical Engineering Technology", "Applied Physics", " Materials Science", "Technology of organic and inorganic substances and the Ecology";</li><li>production and power engineers - from the volume "Energy-saving technology and equipment".</li></ul><p><span lang="EN-US">The goal of the journal is to eliminate the gap, which occurs between the rapidly emerging new scientific knowledge and their introduction in the industry, which requires much more time. Industrial enterprises are active subscribers to the "Eastern-European Journal of Enterprise Technologies", and production engineers check the practical value of those scientific and technological ideas, which are recommended for implementation by scientists-authors of the ''Eastern-European Journal of Enterprise Technologies".</span></p><p><span lang="EN-US">The objective of the journal in achieving the goal is forming a "scientific component" of modern technologies transfer from science to industry. Therefore, in the papers, published in the journal, the emphasis is placed on both scientific novelty, and practical value.</span></p>PRIVAT COMPANY "TECHNOLOGY CENTER"en-USEastern-European Journal of Enterprise Technologies1729-3774<p>Our journal abides by the CREATIVE COMMONS copyright rights and permissions for open access journals.</p><p>Authors, who are published in this journal, agree to the following conditions:</p><p>1. The authors reserve the right to authorship of the work and pass the first publication right of this work to the journal under the terms of a Creative Commons Attribution License, which allows others to freely distribute the published research with the obligatory reference to the authors of the original work and the first publication of the work in this journal.</p><p> 2. The authors have the right to conclude separate supplement agreements that relate to non-exclusive work distribution in the form in which it has been published by the journal (for example, to upload the work to the online storage of the journal or publish it as part of a monograph), provided that the reference to the first publication of the work in this journal is included.</p>The development of methods for determining vibration stochastic fields of technological complexes
http://journals.uran.ua/eejet/article/view/155839
<p>The force effects occurring in technological complexes have been studied on the basis of the analysis of technical diagnostics system. Due to the distinction between deterministic and random force effects, there have been proposed various methods to distinguish the vibration of informational diagnostic characteristics in order to ensure prompt and reliable detection of the rapidly developing defects. Reliable diagnostics will make it possible to switch from a system of scheduled preventive repairs to the organization of repairs for the current state, with a decrease in the cost of repairing and rebuilding the units of technological complexes by early detection of the defects emerging in the assembly components.</p><p>On the basis of analyzing the process of propagation of vibroacoustic waves caused by the power action, there has been developed a mathematical model for the emergence and propagation of elastic waves in sophisticated technological complexes from the places of their origin to the point of observation. There have been suggested kinematic schemes for propagation of low-frequency vibrations, vibrosignals from the brush-collector unit, as well as waves from the inner ring of the bearing. This makes possible to substantiate a mathematical model of the occurrence and propagation of vibroacoustic waves in the parts and units of technological complexes from various sources of vibration.</p><p>The comparative analysis of the research findings on the real vibration fields and the results of numerical modeling confirms the adequacy of the model to the real process. The article presents the graphs of the temporal realization of signals in the model, the spectra of the realized signals, as well as their autocorrelation functions reflecting the main characteristics of the signals at the measurement point. The findings can be used to diagnose and reduce the cost of repair and restoration of the units in sophisticated technological complexes by early detection of the defects emerging in the assembly parts.</p>Nadiia MarchenkoOlena MonchenkoGanna Martyniuk2019-02-282019-02-2819 (97)384710.15587/1729-4061.2019.155839Analytical method to study a mathematical model of wave processes under twopoint time conditions
http://journals.uran.ua/eejet/article/view/155148
<p>Research and analysis of dynamic processes in oscillatory systems are closely connected to the establishment of exact or approximate analytical solutions to the problems of mathematical physics, which model such systems. The mathematical models of wave propagation in oscillatory systems under certain initial conditions at a fixed time are well known in the literature. However, wave processes in lengthy structures subject to an external force only and at the assigned states of the process at two points in time have been insufficiently studied. Such processes are modeled by a two-point time problem for the inhomogeneous wave equation in an unbounded domain t>0, x∈ℝ<sup>s</sup>. The model takes into consideration the assignment of a linear combination with unknown amplitude of oscillations and the rate of its change at two points in time. A two-point problem, generally speaking, is the ill-posed boundary value problem, since the respective homogeneous problem has non-trivial solutions. A class of quasi-polynomials has been established as the class of the existence of a single solution to the problem. This class does not contain the non-trivial elements from the problem's kernel, which ensures the uniqueness of solution to the problem. We have proposed a precise method to build the solution in the specified class. The essence of the method is that the problem's solution is represented as the action of a differential expression, whose symbol is the right-hand side of the equation, on some function of parameters. The function is constructed in a special way using the equation and two-point conditions, and has special features associated with zeroes of the denominator – the characteristic determinant of the problem.</p><p>The method is illustrated by the description of oscillatory processes within an infinite string and a membrane.</p>The main practical application of the constructed method is the possibility to adequately mathematically model the oscillatory systems, which takes into consideration a possibility to control the system's parameters. Such a control over parameters makes it possible to perform optimal synthesis and design of parameters for the relevant technical systems in order to analyze and account for special features in the dynamic modes of oscillationsZinovii NytrebychVolodymyr IlkivPetro PukachOksana MalanchukIhor KohutAndriy Senyk2019-02-272019-02-2719 (97)748310.15587/1729-4061.2019.155148Processes of managing information infrastructure of a digital enterprise in the framework of the «Industry 4.0» concept
http://journals.uran.ua/eejet/article/view/157765
A study of the management of the information infrastructure of a digital enterprise is conducted within the framework of the “Industry 4.0” concept. It is determined that modern digital technologies cause an exponential growth of data flows, for the effective functioning of which the need arises to transform a classic enterprise into digital. There are new business models, network structures based on collective methods of production and consumption, which transform traditional market relations and require the development of new solutions in the field of digital enterprise management. It is noted that the use of all elements (mobility; sociality; BPM, electronic document management system ERP finance and accounting; Big Data Analytics, business analytics) of modern information and communication technologies will increase the productivity and value of enterprises. It is determined that information and communication technologies allow to effectively interact with each other in certain sectors of production and ensure the optimization of any business processes using consumerization. Modern trends in the development of digital enterprises are identified and the prerequisites for the introduction of digitalization in the business space are marked. The constituent elements of the management process of the information infrastructure of a digital enterprise are structured, on the basis of which a model of the information infrastructure management process is proposed. The objectives of the digital infrastructure are substantiated, which are indicated: to increase the speed of decision-making, to increase the variability of processes depending on the needs and characteristics of the client, to reduce the number of employees involved in the process. The methodological foundations of the process of managing the information infrastructure of a digital enterprise are deepened in the context of the “Industry 4.0” conceptKateryna AndriushchenkoVolodymyr RudykOlena RiabchenkoMaryana KachynskaNataliia MarynenkoLidiya SherginaVita KovtunMariia TepliukAlla ZhembaOksana Kuchai2019-02-262019-02-2619 (97)607210.15587/1729-4061.2019.157765Detecting the influence of heat sources on material properties when producing aviation parts by a direct energy deposition method
http://journals.uran.ua/eejet/article/view/157604
<p>Quality of the material obtained by the method of direct energy deposition using three heat sources (plasma arc, electric welding arc and welding arc with cold metal transfer) was studied. AlMg5 alloy wire was used as the filler material.</p><p>The study was conducted to establish at what heat source the deposited material will have the highest physical and mechanical characteristics and performance. It was also necessary to assess quality, size and uniformity of distribution of the deposited layers since these indicators determine accuracy of the resulting product and make it possible to reduce machining allowance.</p><p>Influence of heat sources on formation of surface of deposited plates was revealed: the specimens obtained by the method of plasma surfacing had protrusion height of the deposited layers on the side surface up to 2 mm, the specimens obtained by the method of electric arc and CMT surfacing had protrusion height of 0.5 mm. The obtained data will enable determination of the minimum allowable machining allowance.</p><p>Analysis of chemical composition has shown that each heat source ensured chemical composition of the finished product corresponding to chemical composition of original material. Distribution of alloying elements was uniform among the deposited layers. However, the CMT process provided the most accurate distribution of alloying elements.</p><p>Physical and mechanical properties of the plates obtained by the direct growth method were approximately at the same level with the materials obtained using conventional methods of casting and pressing.</p><p>The specimens obtained by the method of plasma surfacing had the highest values of mechanical properties: σ<sub>t</sub>=28 MPa; σ<sub>0.2</sub>=15 MPa; δ=30.4 % which can be explained by a more dispersed structure and a high level of fusion of the deposited layers.</p>The obtained data will make it possible to determine which heat source is more expedient to use in order to obtain properties necessary for a concrete technological process. They also make it possible to evaluate applicability of the method of direct growth using arc heat sources in mass production of partsMikhail GnatenkoPavel ZhemanyukIgor PetrykSergey SakhnoSergey ChigileichikValery NaumikAlexander OvchinnikovMaria Matkovskaya2019-02-262019-02-2619 (97)495510.15587/1729-4061.2019.157604Advancement of a long arithmetic technology in the construction of algorithms for studying linear systems
http://journals.uran.ua/eejet/article/view/157521
<p>We have advanced the application of algorithms within a method of basic matrices, which are equipped with the technology of long arithmetic to improve the precision of performing the basic operations in the course of studying the ill-conditioned linear systems, specifically, the systems of linear algebraic equations (SLAE). Identification of the fact of ill-conditionality of a system is a rather time-consuming computational procedure. The possibility to control computations entering the state of incorrectness and the impossibility of accumulating calculation errors, which is a desirable property of the methods and algorithms for solving practical problems, were introduced.</p>Modern computers typically use the standard types of integers whose size does not exceed 64 bytes. This hardware limitation was resolved using software, specifically, by developing a proprietary type of data in the form of a special Longnum library in the C++ language (using the STL (Standard Template Library)). Software implementation was aimed at carrying out computations for methods of basic matrices (MBM) and Gauss matrices, that is, long arithmetic for models with rational elements was used. We have proposed the algorithms and computer realization of the Gauss type methods and methods of artificial basic matrices (a variant of the method of basic matrices) in MatLAB environment and Visual C++ environment using precise computation of the methods' elements, first of all, for the ill-conditioned systems of varying dimensionality. The Longnum library with the types of long integers (longint3) and rational numbers (longrat3) with the numerator and denominator of the longint3 type was developed. Arithmetic operations on long integers were performed based on the modern methods, including the Strassen multiplication method. We give the results from the computational experiment employing the mentioned methods, in which test models of the systems were generated, specifically, based on the Gilbert matrices of different dimensionalityVolodymyr KudinViacheslav OnotskyiAli Al-AmmouriLyudmyla Shkvarchuk2019-02-262019-02-2619 (97)142210.15587/1729-4061.2019.157521Design and examination of the new biosoluble casting alloy of the system Mg–Zr–Nd for osteosynthesis
http://journals.uran.ua/eejet/article/view/157495
<p>We have performed a comparative analysis of existing materials for the fabrication of implants and report their physical-mechanical properties; their advantages and disadvantages have been defined. It is shown that magnesium alloys are among the most promising biosoluble materials. They are bioinert and biocompatible, but their use in osteosynthesis is limited mainly by their inadequate mechanical properties due to the high rate of biodegradation, which requires improving them by changing the chemical composition of the alloy.</p><p>In order to develop a new magnesium-based biosoluble alloy, we have selected the most suitable doping systems in accordance with the established criteria.</p><p>Employing the methods of experiment design, we studied the separate and joint influence of zirconium, neodymium and zinc on structure formation and mechanical properties of magnesium alloy. Mathematical models have been constructed that describe the influence of the examined alloying elements on the mechanical properties of the metal. Using the regression equations derived, we have carried out the optimization of the chemical composition of magnesium alloy.</p><p>The industrial and pre-clinical tests of implants made from the designed biosoluble alloy have been performed. Experiments on animals confirmed the absence of toxic effect from the products of degradation of the devised magnesium alloy on a living organism. Studying the influence of the designed alloy on reparative osteogenesis during experiment on rabbits has shown the positive dynamics of bone tissue regeneration without noticeable changes in its structure, which ensures reliable merging of elements in bones at osteosynthesis.</p>It was established that the implants made from the designed alloy possess the necessary level of mechanical properties that match the mechanical properties of bone tissue. At the same time, they are non-toxic and provides a secure bone tissue healing until the complete fracture consolidation. Positive results of the experiments conducted allow us to suggest a favorable prognosis on the possibility of using implants made from the devised biosoluble alloy of the system Mg–Zr–Nd in humansVadim ShalomeevNikita AikinVadim ChorniyValeriy Naumik2019-02-262019-02-2619 (97)404810.15587/1729-4061.2019.157495Change in the physicalmechanical and decorative properties of labradorite under thermal exposure
http://journals.uran.ua/eejet/article/view/157307
<p>We have experimentally investigated samples from the four fields of coarse-grained labradorite, which is extracted in Ukraine. The samples of labradorite were tested at high temperatures of 200, 300, 400, 500, 600, 700, 800, 900 °С.</p><p>Red spots at the surface of samples is the result of oxidation of the metal Fe<sup>2+</sup>: at different fields of labradorite they cover a different area of the sample's surface of natural stone: it ranges from 39 to 60 %. An analysis of the polished labradorite surface after heating revealed that red inclusions are evenly distributed over the surface of labradorite samples. Oxidation of minerals, which is visually observed on all the samples of labradorite, starts at a temperature of 300 °С. One of the features in the research described in this paper is the application of digital image processing in order to quantitatively assess the Fe oxidation area (red spots) at the polished surface of labradorite samples. To a temperature of 500‒600 °С, there is a gradual increase in the oxidized area of the samples' surface. At temperatures above 700 °С, there is a sharp increase in the oxidized area at the samples' surface. In general, the oxidized spots of metals cover between 40 to 60 % of the surface of labradorite samples.</p><p>When heated, the labradorite samples become 50 % brighter than the original value for indicator L in the color system Lab.</p><p>A decrease in the velocity of ultrasonic wave propagation in labradorite samples occurs evenly, without surges. The reason for a decrease in the ultrasonic wave velocity is the formation of defects and cracks in labradorite samples due to an uneven thermal expansion of minerals. At a temperature of 700 °С ° or higher, there is a decrease in the velocity of ultrasound wave propagation in the samples of natural stone.</p><p>At heating, there is a decrease in the indicators for gloss in all labradorite samples. In general, when labradorite was heated up to 900 °С, the samples from the Ocheretyansky deposit lost 11.21 % of their gloss, from the Neviryvsky deposit ‒ 4.03 %, from the Osnikivske deposit ‒ 33.57 %, from the Katerinovsky deposit ‒ 15.3 %.</p>Valentyn KorobiichukVolodymyr ShlapakRuslan SobolevskyiOleksandr SydorovLiubov Shaidetska2019-02-212019-02-2119 (97)142010.15587/1729-4061.2019.157307On the errorcorrecting capabilities of iterative error correction codes
http://journals.uran.ua/eejet/article/view/157299
<p>The influence of the theory of information on development of the error correcting coding theory has been studied. Main differences between the probabilistic approach and the deterministic approach in the analysis of error-correcting capabilities of different classes of linear codes have been demonstrated.</p><p>The automaton hierarchical models for analysis of permutation decoding of cyclic codes have been developed and a cyclic permutation generator based on two Moore automata has been proposed.<ins cite="mailto:1" datetime="2019-02-21T18:50"></ins></p><p>A study has been carried out into the regular and irregular states of linear finite-state machines (LFSM) based on the automaton representation of cyclic codes. A possibility of significant simplification of decoding of cyclic codes based on conversion of irregular LFSM syndromes into regular ones using permutations has been shown.</p><p>The formalized methods for determination of error-correcting capabilities of iteratively decoded cyclic codes (IDCC) have been devised. They imply the replacementof traditional complete checking of all possible options for comparison of code words to directional search for the solution of the assigned problem, which leads to a significant time saving for calculations. The algorithm for determination of error-correcting capabilities of IDCC with respect to double errors is given.</p><p>It has been shown that all iterative codes increase their error-correcting capabilities with an increase in the number of iterations and one can set it as a percentage for errors of various multiplicities. A distribution of error syndromes to separate iterations has been performed, which makes it possible to reduce the length of a check word in a code. As a result, this leads to an increase in a rate of iterative codes in comparison with the traditional correction codes.</p>A comparative analysis of IDCC and LDPC codes has been carried out to determine a scope of their optimal useVasyl Semerenko2019-02-212019-02-2119 (97)313910.15587/1729-4061.2019.157299Analysis of convergence of adaptive singlestep algorithms for the identification of nonstationary objects
http://journals.uran.ua/eejet/article/view/157288
<p>The study deals with the problem of identification of non-stationary parameters of a linear object which can be described by first-order Markovian model, with the help of the simplest in computational terms single-step adaptive identification algorithms – modified algorithms by Kaczmarz and Nagumo-Noda. These algorithms do not require knowledge of information on the degree of non-stationarity of the studied object. When building the model, they use the information only about one step of measurements. Modification involves the use of the regularizing addition in the algorithms to improve their computing properties and avoid division by zero. Using a Markovian model is quite effective because it makes it possible to obtain analytic estimates of the properties of algorithms.</p><p>It was shown that the use of regularizing additions in identification algorithms, while improving stability of algorithms, leads to some slowdown of the process of model construction. The conditions for convergence of regularizing algorithms by Kaczmarz and Nagumo-Noda at the evaluation of stationary parameters in mean and root-mean-square and existing measurement interference were determined.</p>The obtained estimates differ from the existing ones by higher accuracy. Despite this, they are quite general and depend both on the degree of non-stationarity of an object, and on statistical characteristics of interference. In addition, the expressions for the optimal values of the parameters of algorithms, ensuring their maximum rate of convergence under conditions of non-stationarity and the presence of Gaussian interferences, were determined. The obtained analytical expressions contain a series of unknown parameters (estimation error, degree of non-stationarity of an object, statistical characteristics of interferences). For their practical application, it is necessary to use any recurrent procedure for estimation of these unknown parameters and apply the obtained estimates to refine the parameters that are included in the algorithmsOleg RudenkoOleksandr BezsonovOleksandr RomanykValentyn Lebediev2019-02-212019-02-2119 (97)61410.15587/1729-4061.2019.157288Revealing patterns in the aggregation and deposition kinetics of the solid phase in drilling wastewater
http://journals.uran.ua/eejet/article/view/157242
<p>We have investigated the influence of the concentration of the solid phase of drilling wastewater on a change in the sedimentation rate of the solid phase at aggregation when applying a physical-chemical method of water purification using flocculants and coagulants. This is important because a change in the concentration of the solid phase in wastewater is an uncontrolled process during reagent-based purification and it significantly affects the aggregation mechanism, as well as the kinetics of a solid phase sedimentation.</p><p>The study was performed using the model wastewater prepared by diluting the used drilling mud with tap water. It was found that the use of flocculants without coagulants is not effective and does not lead to aggregation. It was established that the optimum dose of the coagulant aluminum sulfate that is capable of disrupting the stability of the disperse system of drilling wastewater is 65 mg/g, while increasing the dosage of coagulant has no effect on the rate of flake deposition. Among the flocculants, the most active one is the anionic flocculant A-19. Sludge thickening results in the destruction of floccules; in 9 minutes, the floccule deposition rate is reduced two-fold. Increasing the concentration of a flocculant from 0.8 mg/g to 1.6 mg/g leads to an increase in the deposition rate of the solid phase by 2‒2.5 times.</p>It is shown that the solid phase concentration affects the sedimentation rate of floccules; optimum conditions for aggregation are observed at a concentration of 4‒6 g/l. Mechanical impacts on aggregates exert a destructive effect depending on the concentration of the solid phase. It has been established that changes in the dispersed system can be observed based on a change in pH, which varies depending on the concentration of the solid phase in drilling wastewater. Increasing the concentration of the solid phase from 1 to 10 g/l leads to the change in pH from 7.2 to 8.3; the introduction of coagulant reduces pH, while the subsequent destruction of aggregates leads to an increase in pH. The data obtained in the course of our research, as well as the proposed procedure, could be used in order to select the optimal dosages of reagents during drilling wastewater treatmentOleksii ShestopalovNadegda RykusovaOksana HettaValeriia AnanievaOleksandr Chynchyk2019-02-212019-02-2119 (97)505810.15587/1729-4061.2019.157242Features of formation of microwave GaAs structures on homo and hetero-transitions for the sub-microconnection of the lsic structures
http://journals.uran.ua/eejet/article/view/157212
<p>The features of the formation of microwave GaAs structures are considered and a set of studies is carried out to create a serial technology of large-scale integrated circuit structures (LSIC), including the number of microwaves on GaAs epitaxial layers deposited on monosilicon substrates.</p><p>The conditions for the formation of a two-dimensional electron gas in hetero-structures with the determination of electron mobility depending on the orientation of the surface were investigated. For hetero-structures on the surface of a semi-insulated GaAs substrate rotated from the plane (100) at an angle of 6–10º with oxygen content on the initial surface С<sub>0</sub>=10–50 % relative to the gallium peak of the Auger spectrum, a strong mobility anisotropy was found due to an increase in the angle of reorientation and incomplete annealing of carbon from the initial surface of the GaAs substrate.</p><p>For the deposited layers of gallium arsenide on monosilicon substrates epitaxial technology is used, which can significantly improve the purity of the obtained material, namely, significantly reduce the level of oxygen and carbon isoconcentration impurities, which strongly affect the charge state of the interface.</p><p>For the formation of structural layers on GaAs, the technology for the formation of nitride layers of Si<sub>3</sub>N<sub>4</sub>, AlN, BN by the magnetron method at low substrate temperatures and a given stoichiometry was developed and investigated. The combination of gallium epitaxial nano-silicon arsenide technology to silicon substrates became realistically possible only with the development of technology of magnetron precipitated buffer layers of germanium.</p>The technology of the formation of logical elements NOT, OR-NOT, AND-NOT of high speed with low threshold voltage is developed, which allows to build high-speed chips of combination and sequential types on complementary structuresStepan NovosiadlyiVolodymyr GrygaBogdan DzundzaSviatoslav NovosiadlyiVolodymyr MandzyukHalyna KlymOmelian Poplavskyi2019-02-202019-02-2019 (97)131910.15587/1729-4061.2019.157212A method to form control over queuing systems taking into consideration the probabilistic character of demand
http://journals.uran.ua/eejet/article/view/157201
<p>Queueing systems (QS) belong to the class of systems the quality of control over which cannot be assessed in real time. In other words, it is impossible to apply methods of classic search optimization at the stage of control design.</p><p>The current practice of control design implies the acquisition of historical data required to model an operational process in order to choose its best control parameters. These parameters include: determining the size of the planning horizon, forecasting interval, the type of a forecasting model. All these parameters represent the degrees of freedom of search optimization. Upon defining these parameters, modeling process is repeated for different values of shift in the demand forecasted value towards the region of large positive values. Such a shift leads to an increase in the QS inventory levels and a decrease in the likelihood of a product deficit occurrence.</p><p>Process efficiency is compromised by both the insurance stocks and a shortage of products. However, experience has shown that a certain shift in control towards an increase in the inventory levels improves the efficiency of their functioning.</p><p>Thus, the task on QS inventory control implies the substantiation of choice of control parameters in the process of cyclic simulation of the operational process based on the set of historical data.</p><p>Despite the long history of the subject, there is no method at present whose application would make it possible to obtain control, the parameters of which could be considered justified. This relates to that the best control parameters are determined not by examining the quality of economic models of an operational process but rather by studying the quality of quantitative models of this process.</p><p>In order to further advance the theory and methods of control, we have constructed an economic-mathematical model of uncoordinated operation. The model proposed takes into consideration the result of interaction between processes in the buffering channel and processes in the client channel that aims to meet customer demand considering a factor of information impact from marketing technologies on the internal and external consumer.</p><p>The structure of the constructed mathematical model has passed the validation procedure for consistency, in the process of comparing the redundant and deficient operations.</p>A procedure for estimation optimization of the simulated process has showed a possibility to determine the optimal control parameters based on the criterion for a maximum criterion of efficiency of operational processIgor LutsenkoIllia DmytriievNina AvanesovaIryna SemenyshynaZhanna RozhnenkoOleg Danileyko2019-02-202019-02-2019 (97)283610.15587/1729-4061.2019.157201Studying the authenticity of the golden element from a mongolian warrior's armor by physicalchemical methods
http://journals.uran.ua/eejet/article/view/157156
<p>We report results from an expert study into the historical artifact of the XIV–XV centuries ‒ the golden armor element of a Mongol warrior. The obtained results allowed us to establish signs of authenticity in the historical values made of gold in a given chronological period.</p><p>The microstructure of the object was investigated at a magnification of 10–20 times, revealing significant fragility and frailty of the metal. At magnification by 150–200 times, we found the system of cracks with triple points, individual caverns, and a cavernous character of the fracture. Furthermore, we have revealed many dislocations of fractures and traces of the metal flow at the surface of the item, as well as traces of tools that had been used to clean it. At magnification by 2,000 times, we found an extremely complex morphology of the metal with numerous caverns, as well as the surface of partially dissolved metal, which retains the contours of ancient scratches.</p><p>We have established that the deeper parts of the alloy partially retained their chemical composition, and the concentration of gold in them is only 62–80 %, while the alloy was refined at the surface in a natural way, therefore, the gold content in it was determined to be within 81–98 %. In addition, in the deeper parts of the alloy, silver concentrations are larger compared with the surface layers, because silver compounds are chemically more active and are carried away from the surface under the action of external factors.</p>We have determined a list of features that indicate the authenticity of the object, and which are unambiguously detected using an electron microscope, as well as based on the results of studying the chemical composition of the surface of the artifact by emission method. In our opinion, it is efficient to use electron microscopy in experts' work in order to confirm authenticity, to identify signs of forgery and traces of restoration of artifacts made from gold alloysVolodymyr IndutnyiNina MerezhkoKateryna Pirkovich2019-02-202019-02-2019 (97)344010.15587/1729-4061.2019.157156Reduction and optimal performance of acyclic adders of binary codes
http://journals.uran.ua/eejet/article/view/157150
<p>The conducted studies have established the prospect of increasing productivity of computing components, in particular, combinational adders, based on applying principles of computation of digital signals of the acyclic model.</p><p>Application of the acyclic model is designed for:</p><p>‒ the process of series (for low-order digits of the adder circuit) and parallel (for the rest of the digits) computation of sum and carry signals. Due to this approach, it is possible, in the end, to reduce complexity of the hardware part of the device and not increase the circuit depth;</p><p>‒ setting the optimal number of computational steps.</p><p>The assumption that the number of computational steps of the directed acyclic graph with two logical operations (AND and XOR) determines optimal number of carry operations in the circuit of the n-bit parallel adder of binary codes was experimentally proved. In particular, this is confirmed by presence of the 8-bit parallel acyclic adder with the circuit depth of 8 standard 2-input logic elements. Connection between the number of computational steps of the acyclic graph and the number of operations of a unit carry to the high-order digit causes the process of comparison of the adder structure with the corresponding acyclic graph. The purpose of this comparison is to set the minimum sufficient number of carry operations for adding binary codes in the circuit of a parallel adder using the parallel carry method.</p><p>Use of the acyclic model is more advantageous in comparison with counterparts due to the following factors:</p><p>‒ less development costs since the acyclic model requires a simpler adder structure;</p><p>‒ presence of an optimization criterion, i.e. the number of computational steps of the acyclic graph indicates the minimum sufficient number of operations of a unit carry to the high-order digit.</p><p>This provides the possibility of obtaining optimum indicators of the adder structure complexity and circuit depth. Compared to counterparts of known 8-bit prefix adder structures, this provides a 14–31% increase in the 8-bit acyclic adder operation quality, e.g. power consumption or chip area depending on the chosen structure,</p>There are grounds to assert possibility of increasing productivity of computing components, in particular, binary code adders applying the principles of computation of digital signals of the acyclic modelMykhailo SolomkoPetro TadeyevYaroslav ZubykOlena Hladka2019-02-202019-02-2019 (97)405310.15587/1729-4061.2019.157150Development of a procedure for determining the basic parameter of aquatic ecosystems functioning ‒ environmental capacity
http://journals.uran.ua/eejet/article/view/157089
<p>Environmental capacity as the main parameter of functioning of aquatic ecosystems was studied. This parameter is an effective indicator of violation of structural and functional processes in the technogenically altered water body. The adapted conceptual model of the system of indicators Actions - State - Consequences was applied.</p><p>In accordance with the developed classification of the system of indicators, balance of environmental capacity of the aquatic ecosystem serves as a part of the integral indicator of state of the aquatic ecosystem, as a consequence of effect of exogenous factors of anthropogenic origin. Due to the use of integrated indicator systems, it was possible to provide not only qualitative but also quantitative characteristics of the environmental capacity.</p><p>Estuary of a medium peneplain river which is the most representative part of the river and reflects consequences of anthropogenic effects occurring in the river basin was selected as a study object. Taking into account the hierarchical pattern of levels of water systems development, the study of the state of medium rivers at a local level will enable development of water conservation measures that will contribute to improvement of water quality in large rivers. The developed procedure can be successfully adapted to other technogenically altered peneplain rivers.</p>The results of the performed mathematical calculations were presented in a form of graphs of dependence of environmental capacity and techno-capacity on numerous parameters of the aquatic ecosystem functioning. Dynamics of changes in these parameters in 2009‒2017 was demonstrated. The study results indicate that biota adapted to a certain level of technogenic pollution and environmental capacity was stable (27‒37) in the period of 2012‒2016 which shows optimal conditions for existence of the aquatic ecosystem. The generalized estimation of changes over the whole period of studies suggests that the loss of environmental capacity (decreased to 13.3) was caused by excessive technogenic impact on the river aquatic ecosystem which predetermines formation of techno-capacity. As a result, a reduction in the level of remaining ecological reserve necessary for restoration of a technogenically altered aquatic ecosystem of the river was observedVolodymyr IsaienkoSvitlana MadzhdYana PysankoKyrylo NikolaievEvgen BovsunovskyiLarysa Cherniak2019-02-192019-02-1919 (97)212810.15587/1729-4061.2019.157089Identification of the state of an object under conditions of fuzzy input data
http://journals.uran.ua/eejet/article/view/157085
The modernization of the methods for identification of the state of objects under conditions of fuzzy input data, described by their membership functions, was performed. The selected direction of improvement of traditional methods is associated with the fundamental features of solving this problem under actual conditions of a small source data sample. Under these conditions, to solve the problem of state identification, it is advisable to transfer to the technology of description of source data, based on the mathematical apparatus of fuzzy mathematics and less demanding in terms of information. This transition required the development of new formal methods for solving specific tasks. In this case, the procedure for solution of the fuzzy system of linear algebraic equations was developed for multidimensional discriminant analysis. To solve the clustering problem, a special procedure of comparison of fuzzy distances between objects of clustering and centers of grouping was proposed. The selected direction of improvement of the traditional method for regression analysis was determined by impossibility of using the classical least squares method under conditions when all variables are described fuzzily. This fact led to the need to construct a special two-step procedure for solving the problem. In this case, the linear combination of the measure of distance of the sought-for solution from the modal one and the measures of compactness of membership function of the explained variable are minimized. The technology of fuzzy regressive analysis was implemented in the important practical case when the source fuzzy data are described by general membership functions of the (L-R) type. In addition, the analytic solution to the problem in the form of calculation formulas was obtained. The discussion showed that the modernization of the classical methods for solving the problem of the state identification, considering the fuzzy nature of representation of source data, made it possible to identify objects under actual conditions of a small sample of fuzzy source dataSerhii SemenovOksana SiraSvitlana GavrylenkoNina Kuchuk2019-02-192019-02-1919 (97)223010.15587/1729-4061.2019.157085Improving the model of decision making about abnormal network state using a positioning system
http://journals.uran.ua/eejet/article/view/157001
<p>We have proposed to supplement the model of decision making about abnormal states of a wireless network under conditions of uncertainty by another attribute ‒ the location of wireless mobile and stationary devices in a controlled network.</p><p>The method of trilateration, based on the measurement of signal strength at three points, is considered. This method has a high accuracy of determining the location of a wireless device, provided that the most accurate model of radio waves propagation is constructed. However, given the specificity of radio waves propagation inside the premise, it is rather difficult to build such a model for them. Therefore, it is proposed to use the method of radio fingerprints. This method is based on the construction of radio maps for each of the three access points, which indicates the signal level from a typical wireless device located at a certain number of reference points. We have also considered the possibility of the combined application of two methods, which will make it possible to determine the location of a wireless device even when it is outside the radio map.</p><p>Experimental studies were carried out, including the creation of radio maps for a room of area 70 m² with 26 reference points. We employed three identical routers and a smartphone. During the experiment, it turned out that, depending on the orientation of the mobile device (in fact, its antenna), the measured power changes, so the radio maps were constructed based on average power for six different positions of the mobile device. It is shown that the level of the signal is almost independent of the door and window position in the room.</p>This analysis of the principles of organizing various types of attacks on wireless networks has revealed that accounting for the position makes it possible to detect attacks of the types "man in the middle" and "false access point" that were not identified by the base model. In addition, the improved model allows determining the source of interference at the "muting" attackIvan AntipovTetyana Vasilenko2019-02-192019-02-1919 (97)61110.15587/1729-4061.2019.157001The influence of the pack decarburizing process with Pinctada maxima shell powder agent on the properties of high carbon steel
http://journals.uran.ua/eejet/article/view/153762
<p>In the present study, ductility enhancement of high carbon steel AISI 420 was conducted by pack decarburizing method to improve mechanical properties of this steel. This specimen was placed in a rectangular box containing pinctada maxima shell powder (PMSP) mixed with the carburizing agent with different percentage variations and heat treated in an oxygen atmosphere at different temperatures and soaking times. Phase analysis results indicated that the pack decarburizing process at a temperature of 900 °C, for soaking time 3 hours and an additional 30 % PMSP in the carburizing agent causing the martensit microstructure, the surface hardness number and thickness of carbon layer decreased but the impact energy of high carbon steel AISI 420 increased. The surface hardness number, carbon layer thickness each respectively decreased by 63 % and 60 %, but impact energy or impact strength increased by 33 %. This phenomenon indicates that the pack decarburizing treatment causes carbon diffusion from the surface of the specimens to the carburizing agent or reverse carbon diffusion occurs, because the concentration of carbon in the carburizing agent is higher than the surface of the specimen. The addition of PMSP in the carburizing agent increases the occurrence of carbon diffusion from the surface of specimens to the carburizing agent or reverse carbon diffusion occurs, because differences in concentration and influence of PMSP contains elements of Ca which function as catalysts or energizers. The results showthat the pack decarburizing process with an additional PMSP in the carburizing agent accelerates the diffusion of carbon atoms out the surface of the specimens (reverse carbon diffusion process), thus decreasing the thickness of the surface carbon layer, surface hardness number and increasing the impact energy</p>Sujita DarmoRudy SoenokoEko SiswantoTeguh Dwi Widodo2019-02-192019-02-1919 (97)61310.15587/1729-4061.2019.153762Construction and investigation of a method for measuring the non-stationary pressure using a wavelet transform
http://journals.uran.ua/eejet/article/view/156959
<p>Automated control systems badly need measurements of fast-changing non-stationary physical quantities in real time, or close to that. In this area, there is a separate group of tasks on measuring the non-stationary pressure in liquids and gases.</p><p>This paper demonstrates that measuring the non-stationary pressure in real time, or close to that, represents a problem on restoring an input signal, which, in terms of mathematics, belongs to the class of ill-posed problems (according to J. Hadamard). We have derived a solution to the inverse problem of measurement that is based on a mathematical model for measuring transformation enabled by a pressure sensor. Based on this solution, we have constructed a measuring method, which implies the wavelet processing of the sensor's output signal. In this case, we suggest that such basic functions of wavelet transformation should be selected that are the modification of the pulse transition function of the sensor.</p><p> This paper reports an experimental study into the feasibility of the developed method, based on the measurement of the simulated pressure pulse. A pressure pulse is simulated by dropping a ball of the calibrated mass onto the sensor's membrane. We have proposed a measurement scheme for determining the duration of touch between the ball and the membrane. Testing the accuracy of the method implies comparing the actual mass of the ball with that derived from the sensor's output signal. The proposed method has demonstrated high accuracy because the maximum relative error in determining the mass of the falling ball was only 0.65 %.</p>The proposed method for measuring the non-stationary pressure could be used in control systems that require the high-speed dynamic correction of a measurement error. Specifically, these include control system in aerospace engineering, testing complexes, military technology, scientific researchMyroslav TykhanTaras RepetyloSerhii KliuchkovskyiOlha Markina2019-02-182019-02-1819 (97)283410.15587/1729-4061.2019.156959Substantiation of parameters for the technological process of restoring machine parts by the method of plastic deformation
http://journals.uran.ua/eejet/article/view/156779
<p>We have studied technological processes related to the restoration of worn-out parts of agricultural machinery (plowshares, cultivator sweeps) that operate under conditions of intensive abrasive wear. We have determined the influence of operating parameters of the technological process on the quality of the restored surface of the cutting elements of machines’ working bodies under conditions of regular and vibration deformation. It was noted that the restoration technologies based on vibratory oscillations make it possible to create new machining methods characterized by higher intensity: the physical-mechanical properties of the recovered parts’ material, their shape and dimensions, as well as machining regimes. We have performed a strain gauge study of changes in the parameters of cutting elements in the working bodies of tillage machines, which made it possible to determine the magnitude of deformation when parts are machined. We have constructed a mathematical model of the dynamics of abrasive wear of the above-specified working bodies, which allowed us to define the patterns in the wear intensity distribution of a working body’s cutting element.</p>Based on the derived curves of density distribution of wear magnitudes for cutting elements in the specified parts, we have defined a wear law that revealed patterns of change in the strained-stressed state of the working surface in a cutting element. We have estimated the influence of basic factors on the processes occurring in the material of parts during operation. The main factors for vibration machining of the parts’ working surface have been established: the amplitude, frequency of oscillations of a machining tool, the time of hardening. The criteria for the threshold condition of parts under conditions of abrasive wear have been defined: the thickness of edge of the cutting element of parts and a change in size. We have established the positive role of compressive stresses when machining the parts’ material in their wear-resistance improvement. A dependence of the magnitude of parts’ wear on the following key factors has been established: their material, restoration technique, operation duration. It has been proven that the use of vibratory oscillations of the machining working body reduces the intensity of wear of parts in tillage machinery, which is important and relevant to improving the reliability of agricultural machinesAnatolii DudnikovVladimir DudnikOlena IvankovaOleksii Burlaka2019-02-152019-02-1519 (97)758010.15587/1729-4061.2019.156779