Pavlov O.I., Bondarenko A.S.
Recognition of Phonendoscope Signals in the Linear Spectrum Parameters Domain of the Highest Regression
Fig. 1. Tabl. 1. Refs.: 14 titles.
In this paper, we study two new effective domains —linear spectrum projections of the highest regression and the linear spectrum frequency of the highest regression. We also consider classic domains of equivalent parameters and reflection coefficients. Furthermore, we compare the results of classifiers structure of phonendoscope signals by using imaging into the solution space with a minimum mean square error.
Modeling of Film Hydrodynamics in the Grid Structure
Fig. 10. Tabl. 1. Refs.: 16 titles.
Our objective is to determine the speed and thickness of the film as principal parameters that present the efficiency of heat mass transfer. To that end, we apply an analytical model of flow infinite cylinder by the perpendicular flow of inviscid fluid. The model is supplemented with the calculation of local liquid film thickness. The experimental results show that the waves appear on the grid surface with the film. It causes the increase of the flow velocity and reduction of the film thickness.
Iemets O.O., Parfonova T.O.
On Estimating the Acceptable Sets of Solutions of Combinatorial Transport Problem on Permutations Solved by the Method of Branches and Bounds
Fig. 1. Refs.: 18 titles.
We estimate the acceptable set in the method of branches and bounds at solving a transport problem on permutations. We prove the property of this estimation. It allows reducing a number of the operations in the method of branches and bounds.
Optimization of Storehouses Filling in Flow Distribution Problems
Refs.: 7 titles.
The present paper aims to construct the mathematical model of transportation and distribution of a certain item among consumers. This model takes into account stocking in tanks for temporary storage. To that end, we propose the algorithms based on the effective methods of nonlinear programming. Due to the general problem statement, these algorithms can be used for calculation of various types of distribution networks.
The Localization Method of the Linear Function Value on Transpositions with Linear Limitations
Fig. 1. Refs.: 15 titles.
The paper considers the task on columns taking into account the properties of a great number of transpositions as domains of possible solutions of this task. We prove and algorithmize the localization method of the linear function value on a combinatorial set of transpositions. We also study the method of values organization of the efficiency function on a great number of transpositions that makes it possible to find the solutions of the task of linear function on transpositions with linear limitations.
Kuznyetsova N.V., Bidyuk P.I.
The Comparative Analysis of the Models’ Characteristics for Credit Rating
Fig. 6. Tabl. 6. Refs.: 10 titles.
This paper analyzes basic methods of the credit rating (decision tree and logistic regression). More precisely, we propose to use the models on Bayesian networks. We construct the appropriate models for the decision tree, logistic regression and Bayesian networks. We calculate the common accuracy of each model, I-type and II-type errors, and build ROC-curves and GINI-index. Finally, we arrive at the conclusion that it’s reasonable to use Bayesian networks.
Maslyanko P.P., Vozniuk S.S., Vozniuk A.S.
Construction of the Metamodel Activity Based on A.N. Leontiev’s Activity Theory
Fig. 5. Tabl. 1. Refs.: 27 titles.
In this paper, we utilize A.N. Leontiev’s activity theory to design the activity metamodel of extended human and organization systems. This metamodel demonstrates the place of policy, strategy and tactics in the activity and enables to represent subject-related aspects in this process. In addition, it can be used to get structural and dynamic representation of organization system and human activities, as well as applied in the design of information-communication systems.
A Model of Dynamics Forecasting
Fig. 6. Refs.: 6 titles.
The paper considers the possibility of formalizing some elements of the complex forecasting process. It is based on the concept of states and a sudden change of behavior. This concept lays the foundation for design of the complex systems dynamics.
On Solving the Antagonistic Game with the Exponential Kernel on the Unit Hypercube of the 2N-dimensional Euclidean Space
Refs.: 8 titles.
This study proves that the antagonistic game, whose exponential kernel has the positive parameter and is determined on the unit hypercube of 2N-dimensional Euclidean space, is not convex. We discover the half-interval of the kernel parameter which is the center of the hypercube as a set of its pure strategies. It ensures that the game is concave and has the solution in the form of the pure optimal strategy of the first player and the mixed optimal strategy of the second player. The latter consists in equiprobable selection of every vertex of the hypercube which is a set of the pure strategies of the second player.
Construction of Didactic Ontology Based on the Analysis of Concept-Thesis Model Elements
Fig. 1. Tabl. 2. Refs.: 16 titles.
The present paper considers the method of didactic ontology (DO) construction in the educational system. It is based on the semantic and syntactic analysis of concept-thesis model elements by using fuzzy logic. We represent some basic rules for determining the didactic sequence relation and provide its mathematical description. Crucially, we introduce the method of DO visualization on the basis of didactic-semantic maps.
On Obtaining the Simplified Formula for Describing the Laminar Flow of Newtonian Liquid in the Rectangular Channel by Utilizing the Influence Method
Fig. 1. Refs.: 18 titles.
The paper presents the formula to describe an isothermal laminar stable flow of incompressible Newtonian liquid in the rectangular channels. This formula simplifies the calculations of various hydrodynamic processes. In addition, it is convenient for further mathematical treatment and has no application limitations unlike the known analytical dependences.
Kopylov V.I., Smyrnov I.V., Antonenko D.O.
Adhesive Properties and Cohesive Resistance of Thermal Sprayed Coatings
Fig. 6. Refs.: 30 titles.
In this paper, we propose several approaches for estimation of adhesion energy of cooperating surfaces at thermodynamic and electron-statistical plasma spraying. We also analyze and calculate basic physical parameters, responsible for increasing a number of atomic bonds and adhesive strength by using the theory of chemical kinetics. These atomic bonds participate in contact interaction of the basis atoms and corpuscles.
The Specificity of Forming the Structure and Mechanical Properties of АМг6л Alloy with the Enhanced Content of Silicon Admixtures after Casting and Heat Treatment
Fig. 3. Tabl. 7. Refs.: 5 titles.
This paper studies the influence of silicon admixtures with the content up to 2 % on the phase-structural composition of АМг6л alloy after casting in the metallic form and heat treatment. Through experiments performed, we determine that it is possible to increase the content of silicon admixtures from 0,2 to 0,5 % for the АМг6л alloy used after casting in the metallic form. It can be increased under the conditions of conserving a high level of mechanical properties when the magnesium content in an alloy is within the limits of 6–6,5 %. Moreover, it is possible to increase the content of silicon admixtures from 0,2 to 1 % for the АМг6л alloy used after the heat treatment. It can also be increased solely under the conditions of conserving a high level of mechanical properties when the magnesium content in an alloy is within the limits of 6–6,5 %.
Legeza V.P., Legeza D.V.
The Conditions of Violation of Cylinder “Clean” Rolling along the Brachistochrone
Fig. 1. Refs.: 29 titles.
We obtain the algebraic equation of the directive line of the fastest cylinder descent in the parametrical form. By utilizing the equation of cylinder motion with the binding reaction, we also determine the conditions of the cylinder rolling without slipping and tearing off along the brachistochrone. On the theoretical side, we get a significant theoretical result: a center of the cylinder masses circumscribes the cycloid when it moves along the brachistochrone.
Lyashenko B.A., Radko O.V., Skuratovskiy A.K.
The Increase of Resource Indexes of Steel Machinery by Applying Energy Saving Surface Strengthening Technologies
Fig. 3. Tabl. 1. Refs.: 7 titles.
This paper studies a structural-phase composition and durability of 38Х2МЮА steel fabrication strengthened by the technology of gasthermocyclic ionic nitriding. Through experiments conducted, we demonstrate that useful operating life of finished parts increases by 2,3 times due to the influence of ionic nitriding treatment on the properties of strengthened surface layers.
Malezhyk M.P., Zazymko N.M.
On Determining the Stress-Strained State near the Free and Supported Aperture in the Anisotropic Plate at Pulse Load
Fig. 7. Refs.: 12 titles.
In this paper, we simulate the dynamic stress condition near the free and supported circular apertures in an anisotropic plate from explosion loading on the photoelastic orthotropic models. Moreover, we study the diffraction of quasi-longitudinal and quasi-transverse stress waves on apertures and analyze the dynamic stress.
Chernega D.F., Kud P.D., Ivanchenko D.V.
The Foundry Aluminium Alloy for Hydrogen-Storage Barrels
Fig. 4. Tabl. 1. Refs.: 6 titles.
This study deals with the influence of hydrogen and out-of-furnace treatment of melt on mechanical properties and corrosion resistance of Ak9 alloy type. We determine that the hydrogen treatment of melt by compounds and the out-of-furnace treatment by a complex modifier further the increase of strength and corrosion resistance of AK9 alloy type. This alloy is recommended as a material for making the protective barrier shell of a vessel of gaseous hydrogen storage.
Bushinsky V., Voronov S., Pankratov V., Rodionov V.
The Method of Technology Glance Control of Tape and Sheet Materials
Fig. 3. Refs.: 7 titles.
This study demonstrates the method of technology glance control of tape and sheet materials based on the measurement of the ratio of the reflected mirror light flow from a controllable material to a total falling light flow. We show that it is necessary to carry out the glance’s measurement of various types of materials (paper, cardboard, wood-fibrous plates etc.) at the angles not less than 75°. It ensures the greatest sensitivity of a method and the least influence of material chromaticity. In line with the standards of the International Commission on Illumination, the error of the method measurement does not exceed 2 %. The method is recommended to be used in the glance meter structure of information-measuring systems of technology control in such branches as paper, chemical, printing and woodworking industries.
Gordienko V.I., Kolobrodov V.G.
The Influence of Fill-Factor by Pixels of an Infra-Red Matrix Detector on the Quality Thermal Images
Fig. 3. Refs.: 8 titles.
The present paper deals with the modulation transfer function of the matrix detector which takes into account the sizes of a pixel, the format and the fill-factor of a matrix. Investigated here is the dependence of image contrast on the Niquist’s frequency from the fill-factor of the matrix.
Lightweight Class Systems of Launch Vehicles Air Start
Fig. 5. Refs.: 12 titles.
This paper analyzes current trends for developing the lightweight class systems of launch vehicle air start. Crucially, we show their basic advantages and disadvantages.
Melaschenko O.M., Ryzhkov L.M.
On Evaluation of Microsatellite Spatial Angular Orientation by Ellipsoid Filter
Fig. 4. Refs.: 6 titles.
This study aims to examine the dynamics of microsatellite at the ellipsoid filter use in the algorithm of its angular orientation determination. Moreover, we compare the accuracy of orientation determination at the use in the control system of ellipsoid filter to Kalman filter.
Chizh I.G., Afonchyna N.B., Yakimenko T.M.
On Determining ranges of eye ametropy and astigmatism by Employing ophthalmology aberrometers
Fig. 5. Tabl. 1. Refs.: 5 titles.
According to the results of eyes refractometry of patients of all age groups, we study the parameters of ametropy and astigmatism. The experimental results show that in accordance with the ametropy and astigmatism value the distribution of patients’ number is not Gaussian. On the experimental side, we demonstrate that operating ranges of the conservative ophthalmology aberrometer are based on the research results.