Volume 6 Issue 6
ELECTRONIC NETWORK JOURNAL "RUSSIAN TECHNOLOGICAL JOURNAL
Volume 6 Issue 6
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INFORMATION SYSTEMS. INFORMATICS. PROBLEMS OF INFORMATION SECURITY |
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Kulikov G.V., |
Abstract Signals with multi-phase shift keying (M-PSK) have long been successfully used in digital information transmission systems with high bandwidth. Their use is regulated by various communication standards. The noise immunity characteristics of their reception against the background of white Gaussian noise are well studied. The article deals with the case when, at the input of the receiver, besides noise, there is a scanning interference. The noise immunity of signal reception with multi-phase shift keying in the presence of noise and scanning interference was analyzed using statistical radio engineering methods. In this case, the interference is represented as a harmonic interference with a frequency varying according to the sawtooth law. Two cases are considered in the study. The first is when the scanning interference does not fall into the zone of the main lobe of the signal spectrum. In this case, its influence is negligible, and it practically does not change the noise immunity of the reception. The second case, when the frequency range of the scan coincides with the zone of the main lobe of the signal spectrum, is more dangerous. The dependences of the probability of a bit error on the deviation frequency of the scanning interference, its intensity and the signal-to-noise ratio are obtained. It is shown that the noise immunity of receiving signals with multi-phase shift keying deteriorates greatly in the presence of scanning interference falling in the region of the main lobe of the spectrum of the useful signal, and this effect is greatly enhanced with increasing signal positionality. When changing the frequency deviation of such interference, its effect on the noise immunity of the M-PSK demodulator changes only slightly. To increase the noise immunity of receiving signals against the background of scanning interference, it is necessary to use interference compensation algorithms, for example, tracking notch filters. Keywords: bit error rate, scanning interference, multiple phase-shift keying, noise immunity. |
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Smirnov A.V. |
Method of simultaneous optimization of radio devices performance in frequency and time domains AbstractA new method of searching for optimal transfer functions of radio circuits and devices was developed. This method allows optimizing performance in the frequency and time domain simultaneously. These tasks cannot be solved by analytical methods. The searching was performed in the coordinatespace of transfer function poles and zeros. The heuristic algorithm of multistart local search type was applied. Computation of transfer function, gain and transient response and goal function was implemented at each step of local search. In order to compute transient response the state space method was employed. This method provides robustness to rounding errors. The proposed method has the advantages of universality and flexibility due to the fact that it allows varying the set of quality parameters and their weighted coefficients in the goal function. Another advantage of this method is its capability of searching a set of Paretooptimal solutions, from which we can select the most suitable one. Some examples of the transient function optimization under conditions of gain-frequency response in the stop-band are considered. The found approximations have performance exceeding that of the Bessel and Butterworth filters. Keywords: optimization, goal function, quality parameter, transfer function, gain-frequency response, phase response, transient response. |
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Sterlyadkin V.V., |
Features of radar reflections from the clear sky in the millimeter wavelength range 23 AbstractThe fine structure and conditions for the occurrence of radar reflections from a cloudless atmosphere in various meteorological conditions and at different times of the year are considered. The few research results in the millimeter wavelength range determine the importance and relevance of the tasks in this area. The results of field measurements carried out using a radar of 8 mm wavelength range at different times of the year under various weather conditions are presented. The possibilities of the developed software for processing and analyzing the data are considered. The obtained data can be used in the design of all-weather small-sized weather radars for various purposes. The parameters of pulse Doppler radars of 8 mm wavelength range for measuring wind profiles in a wide range of weather conditions are presented. Sensing modes, methods for processing and accumulating data using software, as well as the form for presenting the results are indicated. The technique of wind profile recovery in the directions of sounding is considered. The data on radar reflectivity in a clear sky in various meteorological situations are given. Separately, the features of the structure of the Doppler spectra in the millimeter wavelength range when reflected from the clear sky are considered. Keywords: Remote sensing of the atmosphere, millimeter wind profiler, reflections from clear sky, radar, Ka wave band. |
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Tarasov I.E., |
Abstract This article presents a state-of-the-art method of mathematical analysis and implementation of a hardware-accelerated generator of kernel functions based on Morlet wavelet. The method is based on heavy usage of hardware cores of high-performance programmable logic devices (PLD) for generating harmonic and Gaussian modulating functions in real-time mode. The usage of modulated harmonic series allows tuning parameters of kernel functions both in frequency and time domains, while fine tuning of damping factor of Gaussian function is performed on the base of fixed-point representation of wavelet samples. The proposed hardware generator has a feature allowing to create high-order kernel functions, which is impossible with the approach based on storing coefficients in on-chip memory limited in size. An analysis performed in the article allows calculating a set of integration limits and corresponding damping coefficients for Gaussian modulating function. Implementation on the PLD was performed with combination of existing IP-cores based on CORDIC algorithm and original developed components. Modelling and implementation are performed with Kintex-7 series PLD. Using this approach several high-precision systems were designed. These systems are precision measurement devices for frequency and phase measurements. They also may be used for software-defined radio devices, including pure digital implementation of an input radio-frequency signal. Some examples are also reviewed. Keywords: wavelet analysis, digital filter, software-defined radio, information-measurement system, PLD, system-on-chip. |
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ANALYTICAL INSTRUMENTATION AND TECHNOLOGY |
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Velichko A.P. |
Abstract This article considers the possibility of using additional infrared radiometry compensators "transparent" in the operating spectral range of 8–14 µm and having radiating parameters controlled with high accuracy. This will allow a simpler way to register the radiation fluxes of the atmosphere at different zenithal angles without taking into account the hardware function of the radiometer. The constant monitoring of this function is quite a difficult technical task. It is proposed to use a polyethylene film with a thickness of 10 µm as a compensator. Depending on the value of the radiation flow, a certain number of layers of such a film with constantly controlled parameters, which will be a kind of a "reference radiator", are introduced into the measuring channel in front of the radiometer. The article presents theoretical calculations based on the laws of infrared radiation propagation in the Earth's atmosphere, as well as experimental data confirming the expediency of this technique in remote sensing of the atmosphere in the "transparency window". This technique extends the dynamic range of the radiometer in the low temperature range (below 223 K), which is the sensitivity threshold of most radiometers.The temperature of the "clean" atmosphere at the zenith is much lower. Keywords: atmosphere, transparency window, IR radiometer, aerosol, water vapor, wavelength. |
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Titov S.A., |
Abstract Application of a lens multi-element acoustic microscope for the visualization and quantitative characterization of small discontinuities with dimensions of the spatial resolution level is considered. On the basis of the paraxial approximation it was found that the recorded spatio-temporal signal of the microscope ultrasonic array can be treated as an estimation of the scattering function of visualized objects. It was theoretically established that the scattering functions of the observed inhomogeneities can be used for the interpretation of the generated acoustic images. It is shown that the finite size of the array elements constrains the angular resolution of the method due to smoothing of the measured scattering function. Experimental testing of the proposed method was carried out using the developed prototype microscope with a two-dimensional array of square elements and a polystyrene spherical acoustic lens. It was experimentally confirmed that the spatial resolution of the device corresponds to a theoretical estimate obtained by a classical criterion. The generated images of small flat reflectors with different angles of inclination obtained by means of electronic scanning are presented. It is shown that the output array data set is more informative for the quantitative characterization of the discontinuities than their acoustical images. In particular, on the basis of the obtained estimation of the scattering function it was possible to estimate the angle of inclination of the reflectors. Keywords: acoustic microscopy, ultrasonic array, quantitative characterization. |
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MATHEMATIC MODELING |
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Pulkin I.S., |
Properties of the maximum likelihood estimates of the exponent of Pareto distribution 34 AbstractThis paper investigates the statistical properties of maximum likelihood estimation index of the Pareto distribution. In recent years, power distribution laws such as Pareto distribution attract the attention of researchers in various fields of science and technology, from economics and linguistics to Internet traffic analysis. Therefore, the problem of determining the exponent of the power law for a given sample is of exceptional practical importance. It is analytically proved that this estimate is biased, although valid. A formula that eliminates the bias is proposed. Besides, a formula for the variance of the unbiased estimate is analytically derived. In addition, the problem of finding the distribution function and probability density of this estimate as a random variable is set and analytically solved. Next, a formula for mathematical expectation and dispersion based on previously determined probability density is found. The obtained results can be used in various fields of human activity, for example, to predict the intensity of natural and man-made disasters. Keywords: Pareto distribution, method of maximum likelihood, unbiased estimation. |
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PHILOSOPHICAL FOUNDATIONS OF TECHNOLOGY AND SOCIETY |
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Arapov O.G., |
Философские проблемы образования в русской естественнонаучной мысли 36 AbstractThe article is specially devoted to the study of the philosophical understanding of the higher education problem in the context of modern philosophy by Russian scientists. Fundamental principles of higher education development worked out and represented by M. V. Lomonosov, D.I. Mendeleev, V.I. Vernadsky – the greatest naturalists representing Russian science starting from the 18th century up to our times – are considered. Approaches to organizing university education in Russia, to understanding its content and meaning in preparing professional personnel and educating specialist’s character, to forming humanistically oriented creative thinking and to forming stable worldview are shown. The necessity of various spheres and directions of scientific thought is substantiated. The importance of optimal combination of natural-science, special, abstract philosophical knowledge in the education system is shown. It is noted that the success in overcoming many contemporary problems depends on the degree of understanding the importance of strengthening the relation between science and moral and spiritual basis of human and society life. The question of enhancing the role of humanitarian knowledge in the process of forming the research scientist as socially responsible personality is shown to be topical. Keywords: education, philosophy of education, Russian scientists, university, humanitarian knowledge, global problems. |
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Krizhanovskiy I.N. |
Postmodernism: A step in an "inexact direction" 27 AbstractThe article is devoted to the consideration and understanding of postmodernism in the context of its impact on various spheres of society. The author attempts to answer the question of how the onset of a new semantic era coupled with the development of information technologies will affect the state of the society in general and the scientific sphere in particular. The impact of this phenomenon on culture, art (in view of the breadth of the concept, only literature is chosen), social life and science is discussed. Based on the analysis of scientific, publicistic and artistic literary sources, as well as materials from the media, the nature of the trends induced by the sociocultural phenomenon under discussion is established. The author of the article analyzes the works of both apologists of postmodernism (for example, R. Bart, M. Foucault, I. Skoropanova, V. Erofeev) and opponents (for example, J. Baudrillard, A. Dugin, V. Stepin, S. Kara-Murza). We consider relatively new phenomena directly related to the predominance of the philosophical principles of postmodernism in the world information field (for example, “columbiners”, clip thinking, postdemocracy, and some others). The article assesses the attitude of postmodernism to traditional culture and values. The author ascertains the mediated nature of its influence on scientific activity and leans towards a negative assessment of postmodernism (in its present form) as the main ideological principle. Keywords: the influence of postmodernism, society, science, culture, art, trends. |
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