Вісник Київського національного університету імені Тараса Шевченка. Серія: фізико-математичні науки
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Automated information measuring system for monitoring characteristics of atmospheric ozone
Get PDFThe structural diagram of an automated information and measurement system for monitoring the characteristics of atmospheric ozone, the purpose and interaction of the main components of the system are presented. System management software is considered. The results of determination of the total ozone content (TOC), which were obtained by comparing simultaneous data, determined manually by the operator and using the layout of the information-measuring system, with a relative error of measurement difference did not exceed 4.3%. The results of measurements with automatic averaging of the values obtained during the day showed that there was no need to choose windows of cloudless or homogeneous sky. The development can be recommended for use as a basis for the creation of a modern automated information and measurement system for monitoring the characteristics of atmospheric ozone.Key words: block diagram, the total ozone content, software, comparison of the data, layout information measuring system.Pages of the article in the issue: 104-109Language of the article: UkrainianThe structural diagram of an automated information and measurement system for monitoring the characteristics of atmospheric ozone, the purpose and interaction of the main components of the system are presented. System management software is considered. The results of determination of the total ozone content (TOC), which were obtained by comparing simultaneous data, determined manually by the operator and using the layout of the information-measuring system, with a relative error of measurement difference did not exceed 4.3%. The results of measurements with automatic averaging of the values obtained during the day showed that there was no need to choose windows of cloudless or homogeneous sky. The development can be recommended for use as a basis for the creation of a modern automated information and measurement system for monitoring the characteristics of atmospheric ozone.Key words: block diagram, the total ozone content, software, comparison of the data, layout information measuring system.Pages of the article in the issue: 104 - 109Language of the article: Ukrainia
A survey of driver activity recognition from cameras installed in a car
Get PDFThe article discuses approaches to solving the problem of determining the activity of the driver from the cameras installed in the cargiven the actve development of intelligent driver asistance systems in recent years. The aricle provides an overview of the main problems that arise for the driver while driving Main advances in autonomous drving are presented and the classification of types of autonomous vehicles is provided . Next, the methods of solving the identified problems are described. The main part of the article focuses on solving the problem of determining the state of the driver during driving. Reasons for usage of computer vision and machine learning approaches for soving this task are described. The basic paradigms of the solution of his problem - classification of images, classification of a video stream, detection of the basic points of a body of the driver on the image from the camera installed inside a car are investigated. Main ideas of every method are described. The approaches are evaluated with identification of main advantages and drawbacks of the presented methods.Key words: driver activity, driver assistance system, camera, neural network.Pages of the article in the issue: 89 - 94Language of the article: Ukrainia
On matrix representations of oversemigroups of semigroups generated by mutually annihilating 2-potent and 2-nilpotent elements
Get PDFAmong the old results, there are only some results on the representation type of semigroups, namely, for a finite quite simple semigroup (I. S. Ponizovsky) and some semigroups of all transformations of a finite set (I. S. Ponizovsky, C. Ringel); these papers were discussed on finite representation type. If we talk about new results, and even for semigroup classes, then it should be noted works on representations of the semigroups generated by idempotents with partial zero multiplication (V. M. Bondarenko, O. M. Tertychna), semigroups generated by the potential elements (V. M. Bondarenko, O. V. Zubaruk) and representations of direct products of the symmetric second-order semigroup (V. M. Bondarenko, E. M. Kostyshyn). Such semigroups can have both a finite and infinite representation type.V. M. Bondarenko and Ja. V. Zatsikha described representation types of the third-order semigroups over a field, and indicate the canonical form of the matrix representations for any semigroup of finite representation type. This article is devoted to the study of similar problems for oversemigroups of commutative semigroups.Key words: field, oversemigroup, defining relations, matrix representations, tame and wild semigroup, semigroup of finite and infinite types, canonical form.Pages of the article in the issue: 110 - 114Language of the article: Ukrainia
Baxter estimates of the Hurst parameter of fractional Brownian motion
Get PDFIn the paper consistent estimates of the Hurst parameter of fractional Brownian motion are obtained and confidence intervals of the obtained estimates are constructed.In many applications related to data processing, it is necessary to estimate the Hurst parameter. Among such tasks is the task of signal processing and analysis, when the signal can be considered as the imposition of a useful signal and background noise. Background noise is usually a combination of stochastic and fractal components.Numerical indicators of these properties are, respectively, the Hurst index, the stability index, the coefficients of the relationship of increments, which generalize the autocorrelation function. Obviously, the estimation of the Hurst index is a priority in the analysis of self-similar processes.Currently, there are many methods for estimating the Hurst parameter, but they are all focused on individual cases of processes where the property of self-similarity is combined with either long-term dependence (fractional Brownian motion), or with heavy tails.RS-analysis, disperse-time analysis and deviation analysis are most often used in estimating the Hurst parameter. A common feature of these methods is that they are all based on the use of statistical properties of second-order samples (variance, standard deviation, correlation coefficients).Key words: Hurst index, fractional Brownian motion, consistent estimate.Pages of the article in the issue: 18 - 23Language of the article: Ukrainia
On diagonal locally SL-groups
Get PDFLet N be the set of natural numbers. Let F be a field. In [1], we introduced a class of groups SL^p_s (F) and GL^p_s (F) of periodic infinite (N \times N)–matrices that correspond to a Steinitz number s: In this paper we introduce a wider class of diagonal locally SL–groups and GL–groups and study their relations with locally matrix algebras. In particular, we show that every separable–diagonal locally SL–group (respectively GL–group) is isomorphic to a group SL^p_s (F) (respectively GL^p_s (F)).
Pages of the article in the issue: 8 - 11
Language of the article: EnglishLet N be the set of natural numbers. Let F be a field. In [1], we introduced a class of groups SL^p_s (F) and GL^p_s (F) of periodic infinite (N \times N)–matrices that correspond to a Steinitz number s: In this paper we introduce a wider class of diagonal locally SL–groups and GL–groups and study their relations with locally matrix algebras. In particular, we show that every separable–diagonal locally SL–group (respectively GL–group) is isomorphic to a group SL^p_s (F) (respectively GL^p_s (F)).
Pages of the article in the issue: 8 - 11
Language of the article: Englis
Bending vibrations of viscoelastic plates within the Kirchhoff-Love model
Get PDFWithin the framework of the hypotheses of the classical Kirchhoff-Love theory, complete systems of resolving equations are constructed to determine the stress-strain state and the temperature of dissipative heating under steady transverse vibrations of plates made of a linear viscoelastic material, the properties of which depend on the frequency of external excitation and temperature. The equations were obtained without any preliminary suggestions about the law of temperature variation over the plate thickness. This law is determined in the process of solving the problem. The unrelated problem of vibrational bending of viscoelastic plates for complicated way of fixing a contour and different types of thermal boundary conditions is considered. Mathematical models of problems on the steady-state transverse vibrations of plates made of a linear viscoelastic material, the properties of which depend on temperature for an arbitrary law of its change over the thickness of the object. If the material characteristics depend on temperature, investigation of the influence of temperature of dissipative heating is reduced to solution of complicated non-linear systems of differential equations.Key words: viscoelastic plates, dissipative heating, Kirchhoff-Love theory.Pages of the article in the issue: 64 - 67Language of the article: Ukrainia
Adhesive contact of elastic solids with stohastic roughness
Get PDFModel of normal adhesive contact between elastic bodies with stochastic surface roughness is under consideration. Roughness is simulated by Winkler-Fuss nonlinear layer, which can resist to compressive and tensile (in the case of adhesion) contact stresses. Mechanical properties of the layer are determined by statistical theories of adhesive contact between nominally flat rough surfaces. The contact of solids is described by nonlinear boundary integral equations with non-monotonic operators. Their solutions determine reduction of effective thickness of rough layer, contact stresses, contact region, adhesion force. Formulas for adhesion force calculation are presented for the most frequent nominal gap between solids in contact for DMT–theory of contact.Key words: adhesive interaction, contact of rough solids, adhesion force.Pages of the article in the issue: 53 - 56Language of the article: Ukrainia
Sample continuity with probability one for the estimator of impulse response function
Get PDFThe problem of estimation of a stochastic linear system has been a matter of active research for the last years. One of the simplest models considers a ‘black box’ with some input and a certain output. The input may be single or multiple and there is the same choice for the output. This generates a great amount of models that can be considered. The sphere of applications of these models is very extensive, ranging from signal processing and automatic control to econometrics (errors-in-variables models). In this paper a time-invariant continuous linear system is considered with a real-valued impulse response function. We assume that impulse function is square-integrable. Input signal is supposed to be Gaussian stationary stochastic process with known spectral density. A sample input–output crosscorrelogram is taken as an estimator of the response function. The conditions on sample continuousness with probability one for impulse response function are investigated.Key words: impulse response function, linear time-invariant system (LTI), Gaussian process, crosscorrelogram, sample continuity.Pages of the article in the issue: 96 - 102Language of the article: Ukrainia
On central limit theorems for branching processes with dependent immigration
Get PDFIn this paper we consider subcritical and supercritical discrete time branching processes with generati-on dependent immigration. We prove central limit theorems for fluctuation of branching processes with immigration when the mean of immigrating individuals tends to infinity with the generation number and immigration process is m?dependent. The first result states on weak convergence of the fluctuati-on subcritical branching processes with m?dependent immigration to standard normal distribution. In this case, we do not assume that the mean and variance of immigration process are regularly varying at infinity. In contrast, in Theorem 3.2, we suppose that the mean and variance are to be regularly varying at infinity. The proofs are based on direct analytic method of probability theory.Key words: Branching process, immigration, m?dependence.Pages of the article in the issue: 7 - 15Language of the article: Englis
Professor Yu.V. Kozachenko (01.12.1940 - 05.05.2020) - prominent scientist and teacher
Get PDFPages of the article in the issue: 9 - 29Language of the article: Ukrainia