Physics, mathematics, and technology

Physics, mathematics, and technology

Mathematics and computer science

Creation of the Norden normalization of the L-, E-subbundles of the SH -distribution of the projective space

Abstract

Norden 1st and 2nd kind inner normals of the L-, E-subbundle of a special class (SH -distribution) of the regular threefold distributions (H -distributions) of the projective space are constructed.

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A model of mid-scale irregularities of the low-latitude Earth ionosphere : evaluations of a non-linear correction method for the Z-scheme

Abstract

A nonlinear correction of the finite-differential scheme for solution of the cross convection-diffusion equations within models of the Rayleigh — Taylor instability in the equatorial region of the Earth ionosphere is considered. For test problems the experimental value of the approximation order of the offered method of non-linear correction of the finite-differential scheme for different types of limiters is received numerically.

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A finite differences approximation of the boundary value problem of a heat convection in the ladle with steel

Abstract

For the numerical solution of the boundary value problem of convective heat transfer in a ladle while blowing steel argon proposed finite-difference approximation of the original mathematical model of convective heat transfer in a continuous divergence form. Used stable and economical implicit monotone conservative difference scheme.

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Mathematical modeling of synthesis technologies of powder materials for the space robotics

Abstract

The production process is analyzed and a brief description of the main theoretical models of spark plasma sintering (SPS) is given. The experience of the use of numerical modeling by the finite element method (FEM) using specialized software for the study of SPS is examined. Goals and objectives of numerical simulation of the process are formulated. The main shortcomings and limitations of known methods of modeling are outlined.

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Theoretical and experimental physics

Bases of the theory of digital communication systems with not orthogonal carrier frequencies

Abstract

The algorithm of the solution of the task of permission of signals in communication systems with not orthogonal carrier frequencies is provided. A basis are provisions of the theory of optimum reception in the annex to communication systems. It is shown that the system of equations of credibility allows to solve for communication systems the problem of permission of signals in the field of their nonorthogonality. It is shown that the solution of the task of permission of signals in communication systems can be consolidated to the task of filtering with original pulse and frequency responses.

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A semiotic approach to construction of information systems in the field of security

Abstract

The paper is devoted to issues of semiotic approach for the design of information security systems, based on knowledge extraction from semistructured sources. The problems of developing of optimal variants for the prevention of threats to decision support systems. The technique continuous monitoring of text messages, identify the events and situations and develop scenarios possible development of crisis situations is proposed.

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Search algorithms for an extremum in the maximum likelihood method

Abstract

This article presents a comparative evaluation of steepest descent and simulated annealing for the minimization of the likelihood functional for solving the problem of the resolution of two radio pulses on time by maximum likelihood method. The combined algorithm, which allows increasing of the computation performance, wa

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An analysis of possible damage of electrical devices by thunderstorm activity on the model of cloud-to-ground discharge

Abstract

The present work is devoted to analysis of the risk of impact of electric energy of thunderstorm activity on the electrical devices, including home appliances, located in areas with low-rise buildings and in rural areas.

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An automation of the case centers synthesis on the basis of the organizations universal pattern VSM Cenose

Abstract

Today there is a great need for computer systems that support decisionmaking class situation centre at the Federal and regional level, for large, medium and small enterprises. The technology of auto-automation of the synthesis of the situational centers for all subject areas, to simplify the design of situational centers and reducing its cost.

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A development of the low power engine for work on a krypton

Abstract

Addressing such space mission as station keeping at the orbit, satellite orbit rising, debris deorbiting, cargo transportation and development of thrusters for deep space missions, electric propulsion appears to be an undisputed alternative for the chemical thrusters. Also, even the best solutions provided by electric propulsion technology still require optimization despite its more than of half a century history. Currently xenon is the propellant of choice for ion and Hall effect thrusters, however xenon is very expensive, that’s why different cheaper propellants appears as an alternative fuel for advanced electric propulsion thrusters

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Mechanics