Physics, mathematics, and technology

2016 Issue №3

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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