UDC 621.372.061
The Image Restoration Algorithms by Conventional Deconvolution / Ivanyuk N.O. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 7–15.
The modified conventional deconvolution method using discrete orthogonal transformations is proposed. The algorithms for method realization in Hadamard transformation field and in RTF basis are considered. RTF transformation is different from Fourier transformation and is the “calque” of difference methods. The main problem of algorithm realization – forming image degradation inverse matrix by symbolic method of any order of matrix forming – is solved. These algorithms for conventional deconvolution method significantly allow simplifying the computations independently of matrix order. Using symbolic methods to realize these algorithms allows increasing computational time thereby; numerous additions and subtractions of the same quantities are excluded. This helps to reduce operational accuracy. This modified restoration method in Hadamard transformation basis is easily programmed. The examples of standard images restoration with different noise level and degradation characteristics (with known impulse responses) are given.
Keywords: image degradation matrix, conventional deconvolution, Hadamard transformation, symbolic method.
Fig. 5. Refs.: 23 titles.
UDC 621.314
Comparative Analysis of Average Risk Using the Recommended Limit Concentration of Gases Dissolved in Oil for Detecting Defects in Transformers 110 kV / Abramov V.B., Shutenko O.V., Baklay D.M. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 16–26.
The comparative analysis of values of average risk, which are accompanied by use of boundary values of concentration of the gases dissolved in oil recommended by known techniques, is presented in this article. For the solution of the given problem, expression for calculation of average risk taking into account laws of distributions of concentration of gases for defectless states and defective states, in conditions, when diagnostics is made on a complex of diagnostic parameters is offered. Using methods of numerical integration, probabilities of correct and erroneous decisions for each of five methods have been calculated. The performed analysis of the received values of average risk has shown that the minimum economic losses will be accompanied by use of boundary concentration recommended by method IEC 60599. Dependences of values of average risks on probability of occurrence of defects in power transformers of a class 110 кВ not hermetically execution were investigated. Analyzed dependences of values of average risks on relation of the prices erroneous decisions. Distinctions in character of these dependences for various techniques were established. The analysis of dependences of value of average risk on probability of occurrence of defects and relations of the prices from erroneous decisions, has specified in necessity of updating of boundary values of concentration of gases taking into account the given factors.
Keywords: diagnostics, defects recognition, methods of interpreting the results of chromatographic analysis, the laws of distribution of gas concentrations, the probability of error types I and II, the average risk.
Fig. 4. Tabl. 5. Refs.: 15 titles.
UDC 681.5.015.8:519
Dynamic Model Heat-Mass Exchange for the Water Cooler of the Industrial Air Conditioner / Golinko I.M. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 27–34.
Mathematical modelling of processes heat-mass exchange for a water cooler, which is used in systems of an artificial microclimate for cooling and air unwatering, is observed. Based on the equations of material and thermal balance two equivalent models allowing to spend modelling of transients in a cooler on the basic channels of regulating and perturbation are gained. Sampling of dynamic model is defined by methods of a control system synthesis of the industrial air conditioner. For raise of accuracy of mathematical calculations in paper experimental definition of factors heat-mass exchange, which allows adapting dynamic model for concrete operating conditions of a water cooler, is offered. The offered mathematical dependences are conveniently realized in the environment of MatLab. The instance of modelling of transients for water cooler CVP 2-SW4 air conditioner CV-P 2L N-63B/F-N which is manufactured by company VTS CLIMA is resulted. The gained transients have aperiodic character without delay. On character of transients, for management of a water cooler it is possible to recommend the PI-regulator. The dynamic model of a water cooler can be used by specialists on automation for the analysis and adjustment of parametres of control systems of industrial air conditioners.
Keywords: heat-exchange apparatus, heat exchange, mass exchange, air conditioner, dynamic model, transients.
Fig. 3. Тabl. 1. Refs.: 12 titles.
UDC 621.315.1.015.532
A Hundredth Anniversary of the Peek’s Law for Estimating the Corona Inception Electric Field / Protsenko О.R., Trotsenko Ye.O. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 35–41.
This article is dedicated to the memory of well-known electrical engineer Frank William Peek, Junior, who estimated the corona inception electric field on the surface of electrodes with a small radius of curvature which allows for corona discharge inception and also known as the “Peek’s law”. Analyzing Peek’s first publications dated 1911–1915, we have seen that he has elaborated and summarized the laws, which describe the phenomenon of corona discharge in gas on the wires of power transmission line. In particular, Peek presented the final version of the half-empirical formula in 1915, which allows estimating the voltage under which a corona appears on high-voltage wires, as well as estimating the power loss caused by this phenomenon. Attention has been drawn to the unrenowned facts related to Peek’s discovery of the formula. It has been discovered that the scientist was using the mean-value method when working on the formula. Also, attention has been drawn to the reasons of difference in indices (coefficients) in Peek’s formula, which can be seen in literature and publications of different authors in our country, as well as other countries. Based on the results of the research of Peek’s successors, it has been shown that all new charts repeat his formula and differ from it only by the value of numeric coefficients and, sometimes, the exponent in the denominator. Three ways of using his formula have been summarized; its direct application in electric power industry has been shown.
Keywords: Frank William Peek, Peek’s law, corona, corona inception electric field, transmission line.
Fig. 1. Refs.: 8 titles.
UDC 620.92
Performance Characteristics of Aluminum Thermosyphon for PVT Solar Collector / Khairnasov S.M., Rassamakin B.M., Alekseik E.S., Anisimova A.A. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 42–48.
This article discusses the design of aluminum profile thermosyphons intended for use in PVT solar collectors. PVT solar collectors can simultaneously convert solar energy into electricity and heat, thus increasing the efficiency of solar power installation. The analysis of experimental studies of performance aluminum profile thermosyphons was presented. Graphical dependencies according to their maximum capacity and heat transportation, thermal resistance on the angle relative to the horizon, as well as the heat transfer coefficients in the evaporation zone of a let down on the density of heat flow were presented. The studies were conducted for outside diameters of their hulls 8, 10 and 14 mm; angles in the range from 5 to 90° and in the temperature range from 20 to 80 °C. The analysis of the experimental data allowed us to select the most optimal design of aluminum profile thermosyphon, which outer diameter is 10 mm. This thermosyphon transmits heat flux of more than 150 W, and the thermal resistance of not more than 0.04 K/W for tilt angles of combined solar collector more than 10 degrees.
Keywords: heat pipe, thermosyphon, solar thermal collectors, PVT solar collectors.
Fig. 7. Тabl. 1. Refs.: 14 titles.
UDC 519.246.8
Estimation of Generalized Linear Models Using Bayesian Approach in Actuarial Modeling / Bidyuk P.I., Trukhan S.V. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 49–55.
The article deals with Bayesian methodology for estimating unknown parameters of mathematical models and the method of analysis statistic data in insurance based on generalized linear models. These models are extension of linear regression when distribution of random variable can differ from normal. For estimating the parameters of proposed models classical and Bayesian approach were used. The main advantage of Bayesian approach is its ability to generate not only accurate estimates but probability distributions too. It gives the opportunity to describe in details the structure and the nature of investigated models. The value of damages in autoinsurance were hired for creating the forecasting model of actuarial process. The model with Poisson distribution and an exponential link function turned out to be acceptable for further use because it has minimum value of observation error and reliable estimate for risk value which was received using Bayesian approach. A normal model with identity link function allows to generate a result after one iteration with small value of observation error but “weak” predicted value of losses and poor risk assessment.
Keywords: Bayesian parameter estimation, generalized linear model, actuarial modeling, forecasting loss in insurance.
Fig. 2. Tabl. 3. Refs.: 10 titles.
UDC 004.8
Improving Adequacy of Type-2 Fuzzy Models by Using Type-2 Fuzzy Sets / Kondratenko N.R. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 56–61.
An information approach to fuzzy modeling was considered. The present paper formulates the task of developing a formal approach, which would enable analyzing fuzzy systems in terms of their capability to describe uncertainties of input information using interval membership functions. The discussed approach would allow to introduce the information factor for evaluating the quality of fuzzy models functioning using interval membership functions, and to increase the adequacy of the application area representation by a developed fuzzy model. The proposed information factor is a target function based on type-2 interval membership functions. The introduced target function optimizes the quantity of mutual information that is reflected from the inputs of a fuzzy model to its outputs. A technique for generating fuzzy type-2 models, which are optimal according to the given quality factor, and an algorithm for building an interval fuzzy model from experimental data and implementing the transition from regular to interval membership functions were introduced. An example of the calculations using this technique for computing the entropy estimation on a fuzzy model’s output is given.
Keywords: type-2 fuzzy model, interval membership function, information approach, optimization function, entropy, information quality factor.
Fig. 5. Refs.: 9 titles.
UDC 004.93’1
The Information Technology of Automated Data Processing in the Multi-Channel Ultrasonic Measurement Systems Menyaylenko A.S., Zakhozhay O.I. – 4 – N 6 – P 62–67
The article is devoted to the application of information technology for the ultrasonic measurement of linear distances. The most attention is done on improving the accuracy and expansion bands of measurement. For that problem’s solving, using of the multi-channel ultrasonic measuring system that consists a plurality of sensors with various measuring characteristics is proposed. To ensure constantly high measurement accuracy in a wide range, a new information technology of automated data processing in multi-channel ultrasonic measurement systems, which are based on a multi-threaded data received from a plurality of sensors and determine the most reliable measurement result, have been proposed.
Keywords: ultrasonic measurement systems, improving accuracy and expansion bands of ultrasonic measurement, multichannel measurement systems.
Fig 7 Refs.: 8 titles.
UDC 512.715:512.772.1:688.321
Application of Discrete Structures and Numerical Sequences in Block Codes / Skuratovskii R.V., Trembovetska O.I. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 68–75.
The purpose to compress information using composition of universal codes with the recursive algorithm of original data recovery was achieved in this work. It obtains compression coefficient higher than in symbolic coding. Proposed method of time coding has reasonable values of compression coefficient and its purpose is coding with compression. For this purpose, entirely new kind of universal coding with the polybasic numeral system was created. The presented method is subtype of universal codes and has an advantage over the Huffman coding for compression, because there is no need to know the exact probability distribution that gives us the characters in the initial data stream and it is a subspecies of the universal coding. The Huffman coding requires exact probability distribution. But when we talk about universal coding it is sufficient to know only the relative order of these probabilities (symbol, are more often, the second of the most common symbol, etc.) withal. Created coding method can be applied in mobile communication and in means of closed communication, if it will be used with block codes, which doesn’t scatter symbol frequencies, because it meets modern requirements for cyphering.
Keywords: code, algorithm, archiving, encryption.
Fig. 1. Refs.: 7 titles.
UDC 681.516.77:519.72
Composite Design Pattern Application and Application of the LINQ Technology in the Context of the Prefix Encoding of Text Using the Huffman Algorithm / Soloshenko O.M. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 76–82.
The designed methods are the implementation of the object-oriented architecture as the class diagram corresponding to the implementation of the Composite design pattern according to the requirements of the flexible implementation of the Huffman tree, the method of the dynamic iterative Huffman tree building. This tree uses the dynamic collection of the node interface using the Visual C# language and the creation method of the initial set of the leaf nodes using the LINQ technology. The implementation methodologies are the idea of the Composite design pattern for the handling with the tree hierarchical structures, the possibilities of the Visual Studio 2010 integrated development environment and the possibilities of the .NET 4.0 Framework and the LINQ technology within Visual C# programming language. The research results are the object-oriented program code in Visual C# language and the class diagram in UML language that illustrates application of the design pattern and principles of inheritance, abstraction, polymorphism and encapsulation for the implementation of the flexible and scalable object architecture of the Huffman tree. The advantages of the mentioned software architecture, the examples of the organization and the storage of large arrays of the text data with the key for decoding symbol table are presented. This proves practical value of the Shannon lemma in the field of information and coding theory.
Keywords: Huffman algorithm, Huffman coding, object-oriented design, Composite design pattern, LINQ, Visual C#,
information and coding theory, prefix encoding, entropy, Shannon lemma.
Fig. 2. Refs.: 6 titles.
UDC 532.542
The Study of the Structure of Laminar Currents in Recirculating Channels with Developed Surface / Berdnyk O.M. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 83–87.
In order to research influence of parameters of the developed surface on structure of a laminar current of viscous incompressible liquid in ring channels the computing model, and algorithm of creation of profiles of speed has been offered. This case deals with a homogeneous layer of obstacles – cylindrical protrusions, distance between which ensures the absence of hydrodynamics interactions. Numerical calculations allowed analyzing dependence of the maximum and average speeds of a stream from density of ledges on a surface of the channel and from their height. In practical standpoint the mathematical model is significant only when moving liquids with very low speed or in fine capillaries, or at conditions from enough viscous liquids (so-called “creeping flow” when Re<<1). Check of reliability of the received results is executed on limit cases which lead to already known tasks. Research showed that the offered computing model adequately displays the main features of process. The presented technique of creation of speed profiles of a laminar stream in ring channels with the developed surface can be used for further studying of a turbulent mode, and for developing engineering methods of calculation of ring channels with turbulizers.
Keywords: duct flows, developed surface, mathematical models of viscous flows.
Fig. 3. Таbl. 1. Refs.: 9 titles.
UDC 621.923.6:621.318.4:621.002.3
Researches of Surface Quality Parameters of High Speed Sliding Bearings from Composite Materials for Printing Machines at DIamond Grinding / Gavrish А.P., Roik Т.A., Кyrychok P.O., Vitsuk Yu.Yu., Oliynik V.G. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 88–93.
In the article the research results of defect layers formation on surface of high-speed sliding bearings made of new high-alloy composite materials from tool steels wastes and intended for printing machines have been presented. Such quality parameters of surface like cold-work strengthening and distortions of the 2-nd type are supplied by the result of interaction between force and temperature fields appearing on the top of diamond grain at fine diamond grinding of friction surfaces of sliding bearings were shown. It was proved, that final quality of surface depends on interaction of simultaneously arising processes of strengthening and tempering of working surfaces of sliding bearings at diamond grinding. It was defined, that the dependences of cold-work strengthening degree, its depth and distortions of the 2-nd type from composition of diamond tool, its graininess, bond type of diamond disc, parameters of grinding: using lubricating and cooling liquid, depth of grinding, rotation speed of the disc and line feed. The practical recommendations were formulated for choice of diamond grinding tools and cutting parameters, which meet the requirements of working surfaces quality of high-speed bearing for rotary printing machines.
Keywords: new composite alloys, force field, temperature, cutting forces’ components, cold-work strengthening, friction pieces of printing machines, fine diamond grinding.
Tabl. 5. Refs.: 14 titles.
UDC 519.6+531/534
Mathematical Modelling of Dynamics of the Vibroprotective System Equipped with Roller Absorber / Legeza D.V. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 94–101.
Using the methods of mathematical modeling to develop numeral-analytical approach for determination of equations of ACHKH of the nonlinear vibroprotective system with a new isochronous roller absorber in the first approaching and to define the optimum parameters of its tuning. For the conclusion of equations ACHKH the averaging method of W. Ritz, adapted to the probed task, was used. For the solution of nonlinear algebraic equations of ACHKH of the system the special programmatic complex was developed in a non-obvious form. For determination of optimum parameters of tuning of roller absorber, a numeral-graphic method is offered and a numeral experiment is conducted on determination of the indicated parameters. It is set on the basis of numeral experiment, that the own frequency of the optimum adjusted absorber in the nonlinear raising does not coincide with the own frequency of the optimum adjusted absorber in the linear raising. In addition, the maximal values of amplitudes of bearing body for linear and nonlinear tasks differ substantially: a rejection makes about 10 % (less than for a nonlinear task). Main advantage of the offered roller absorber consists of that frequency of own oscillations of absorber does not depend on the relative rejections of its working body. Therefore even at the large relative rejections of working body of absorber originally adjusted his parameters remain stable, and oscillations — isochronous. It is determined that the offered absorber is effective enough: it is possible using it to decrease substantially the level of amplitudes of the forced oscillations of bearings bodies.
Keywords: vibroprotective system, isochronous roller absorber, brachystochrone for a roller, settled forced oscillations, amplitude-frequency characteristic, parameters of tuning of absorber.
Fig. 5. Refs.: 28 titles.
UDC 621.785:669.046
Physical and Chemical Conditions of Complex Saturation Carbon Steel 45 by Silicon and Chrome in Medium of Chlorine / Pogrebova I.S., Iantsevitch C.V., Khyzhniak V.G., Loskutova T.V. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 102–105.
The package of the applied programs with base of the thermodynamic data was used and the theoretical analysis of physical and chemical conditions of complex saturation carbon steel by silicon and chrome in medium of chlorine in the closed reactionary space was carried out at the lowered pressure of a gas phase. The influence of structure of initial components of a sating mix on equilibrium structure gas and condensed of phases of process chromosilicided is revealed. It was theoretically proved that the opportunity of simultaneous application of chrome and silicon on a surface of steel and appearance on steel in medium of chlorine complex diffusion layers is experimentally confirmed based on chrome and silicon. Simultaneous saturation of steel 45 chrome and silicon in chlorine atmosphere for 6 hours at a temperature of 1323 K and a pressure of 102 Pa of the gas phase was carried out in this work. The X-ray diffraction studies, it was found that under the assumed conditions of saturation on the steel surface 45 formed diffusion layer thickness of 90–100 microns, which corresponds to the phase of the corresponding chromium carbides Cr23C6 and Cr7C3, doped silicon (outer coat coatings) and a solid solution of chromium and silicon in α-iron (an inner coatings layer). Using micro X-ray analysis, it was found that the outer zone of the coating of chromium carbide Cr23C6 contains up to 52.87 atomic % chromium, except that it dissolves a small amount of silicon (0.15 % atm.) and iron (up to 15.73 % at.). Located directly underneath the zone based on α-iron which contains 9.87–5.55 % at. chromium, 8.15–3.89 % at. silicon 72.47–84.69 % at. iron.
Keywords: chromosilicide coatings, gas and condensed of phases.
Fig. 2. Tabl. 1. Refs.: 9 titles.
UDC 621.384.3
Temperature Measurement Uncertainty of Patient by Medical Thermal Imager / Ahmed Malik Lazim Al-Mzirawi, Kolobrodov V.G. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 106–109.
The purpose of this article is to develop the method of estimation and research of measurement temperature uncertainty by the medical thermal imager in pathological zones depending on the distance between the patient and the thermal imager. The proposed method is based on the noise equivalent temperature difference (NETD) which depends on the linear objective magnification of the thermal imager. The absolute measurement uncertainty is defined as the difference between two NETD in the case the object of observation is at a distance of temperature measurement and at infinity of the thermal imager. The obtained equations for the estimation of the absolute and the fractional temperature measurement uncertainty depending on the objective magnification and the distance between the thermal imager and the patient. The required interval of the change in objective magnification has been defined, which depends on the pathogenic zone dimensions, micro bolometer matrix dimensions and the objective focus length. The example of the appliance of the proposed method for the determination of the temperature measurement uncertainty by the thermal medical imager has been considered. It also has been found out that when the patient is on the distance more than 1 m far from the medical thermal imager the examined measurement uncertainties can be not considered. Over a distance of 50 cm the significant uncertainties take place, which are recommended to compensate by the using of the special infrared objectives.
Keywords: medical thermal imager, temperature measurement uncertainty, noise equivalent temperature difference.
Fig. 4. Refs.: 9 titles.
UDC 661.52:662.2
Influence of Preconditioning on the Absorbency and Strengh of Ammonium Nitrate Granules Grade B / Kovalenko I.L., Kuprin V.P. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 110–114.
The retention capacity of granulated ammonium nitrate grade B with respect to the liquid fuel due to pretreatment of the granules has been increased, and energy-condensed systems for mining have been developed. Processing technology including opening of hard shell of granules without formation of through pores and creating a rigid framework of slightly soluble compounds in the pores. It has been found, that treatment with a solution of iron (III) chloride and further heating provides formation of iron (III) hydroxyl compounds framework with the developed surface in the pores of granules. It increases the retention capacity of saltpeter with respect to the liquid fuel from 2.5 to 6 % by weight while maintaining the strength of the granules. Introduction of stearin, which is surface active and binds chemically with iron (III) compounds, into the liquid fuel increases the retention capacity of granules over 7 %. The technology enables to create energy-condensed systems containing an oxidation catalyst of fuel directly on the surface of saltpeter granules. Based on research a high-performance and secure energy-condensed system for rock breaking in underground conditions Ukrainit–ANFO has been obtained.
Keywords: ammonium nitrate, retention capacity, fuel, energy-condensed system.
Tabl. 2. Refs.: 11 titles.
UDC 546.05:546.723-12
Fine-Dispersed Iron (III) Oxyhydroxides Synthesis: Carbamide Precipitation / Kоrchugаnоvа О.М., Ovsienko O.L., Аbuzarova К.R. // Наукові вісті НТУУ “КПІ”. – 2014. – N 6. – P. 115–119.
The conditions of carbamide precipitation synthesis of fine-dispersed iron (III) oxyhidroxides from iron (III) sulphate and nitrate solutions were found out. In order to determine the necessary precipitant amount potentiometric precipitation titration of iron (III) sulphate and nitrate solutions with ammonia and hydrolyzed carbamide solutions were carried out. The results of these researches are expounded. The results of the investigations of precipitates properties, which were obtained from different initial solutions and characterized by different aging time, such as the precipitates phase composition and filtration properties, were presented. It was found, that the precipitation process from iron nitrate solution has less material consumption. Obtained precipitates have nanometer dispersity and the best filtration properties (less precipitant resistivity). The properties and composition changes depended on the aging time were revealed. It was determined that the filtration, physical and chemical properties of precipitates, which were obtained from the iron nitrate solution, are almost independent of the aging time. According to the results of X-ray analysis the crystal size is about 40 nm.
Keywords: iron oxyhydroxide, iron (III) salt, carbamide, chemical precipitation.
Fig. 3. Tabl. 3. Refs.: 12 titles.