IKBFU's Vestnik

Physics, mathematics, and technology

Mathematics and computer science

Eliseeva N. A., Popov Y. I.

Abstract

The authors construct Foss and Green's normalizations in Norden's sense internally invariantly. The research sets tangent affine connections and tangent central affine connections of the main structural subbundles of H(L, L)-distribution of affine space.

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Program realization of calculation method of radio signal attenuation in atmospheric gases for satellite communications

Abstract

The authors study the application of calculation method of radio signal attenuation in atmospheric gases, proposed by International Telecommunica­tion Union [1]. The paper describes the algorithm of attenuation calculation, created in MATLAB program and calculated resulting attenuation for latitu­des are greater than 45°.

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The export control system automatization

Abstract

The paper considers one of the options for automation of the export con­trol system taking into account the norms of modern Russian legislation. It is concluded that the best option for such an information system is a web appli­cation. The model of classes of export control system by means of UML nota­tion was developed. The paper describes the main roles of users in this system and their functionality. The authors also preliminarily estimate of the time re­quired to process the document before and after the implementation of the in­formation system.

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Developing an employee outflow predicting model

Abstract

For many manufacturing enterprises and large companies which emply many people, there is a problem of staff turnover and, thus, unreliability. As a result, management can't effectively control the outflow of highly qualified personnel, which can result in reduced productivity. The author sees his task in addressing this issue through building a predictive model of the employee outflow. The research included reviewing a dataset of employee outflow, de­veloping some machine learning algorithms and testing a predictive model.

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Investigation of the conditions of applicability of Wiener's attack on the RSA cryptosystem

Abstract

The paper considers the Wiener’s attack for a small secret key in the RSA cryptosystem. Presented a new bound on the secret key, derived under more general assumptions. It is shown that the obtained bound is more accurate than the Wiener’s bound under the classical conditions. The conditions of ap­plicability of Wiener's attack when the bound on the secret key is exceeded. Recommendations on the choice of parameters for the cryptosystem developer are given.

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Theoretical and experimental physics

Numerical model operation of the mass transfer of the disperse phase of aerosol in nonlinear wave fields for axisymmetric quasithree-dimensional geometrical statement

Abstract

The article describes numerical modelling of fluctuations of an aerosol column in pipes at resonant frequencies. The author suggests a mathematical model of dynamics of the heterogeneous medium-mix with approximately equal component mass fractions. The mathematical model suggests the solu­tion of a dynamics equation system for each of the mix component. The carrier medium is a viscous, compressible, heat-conducting gas. The dispersed com­ponent of the aerosol is described by the equation of conservation of average density, the equations of the pulse components conservation, the equation of energy conservation. The mathematical model considers interaction forces of gas and particles of aerosol, as such forces is considered, Stokes's force, Ar­chimedes force and force of the attached masses, as well as heat exchange in­tercomponent. Within the system of the equations of mathematical model, eight equations were solved by means of the final and differential algorithm implemented as a program code. The equations of mathematical model were complemented with the corresponding entry and boundary conditions. Ha­ving obtained the numerical model, the author studies the regularities of the re­distribution of the aerosol dispersed component density of in wave fields. The research reveals the influence of droplet size on the distribution of the dis­persed component of a multiphase medium in the process of resonant oscilla­tions in pipes.

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Calculation method of the channel potential possibilities of surface vessel radiocommunication system in the mode of pseudo-random frequency tuning

Abstract

The article is devoted to the definition of methodological approaches to the development of multi-channel duplex radio communication systems that en­sure reliable operation on a surface vessel. The research provides analytical expressions for the calculation of the possible number of transmit-receive channels in the model, depending on the signal spectrum width in the chan­nel. The proposed software allows you to quickly calculate the parameters of the communication system.

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Mechanics

Simulation of turbulent flow of viscous liquids with dispersed inclusions of close density

Abstract

The authors consider the methods and algorithms for calculating the characteristics of hydro-mechanical processes in the flow of viscous liquid (wa­ter) with dispersed inclusions of close density. In particular, the dependences of the dimensionless intensity of the pulsation energy dissipation on the inert­ness of inclusions at different loads are investigated. The paper presents the results of the solution by the boundary numerical method in Mathcad. It is found that the intensity of the pulsation energy dissipation of the carrier me­dium is directly proportional to the ratio of the distributed density of the dis­persed phase and the carrier phase depends on the inertia of the inclusions, characterized by a dimensionless value.

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