ISSN 0021-3454 (print version)
ISSN 2500-0381 (online version)
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Summaries of the issue

INFORMATION TECHNOLOGIES AND SYSTEMS

301
A technique is presented that can be used to identify the error of prediction of divergence of time scales discordance for space-distributed clocks. The proposed approach accounts for the error of com-paring the time scales of remote clocks as well as nonstationary properties of the time scale generation process dependent on the master clock generator parameters. The approach makes it possible to gene-ralize the numerical solution obtained for the problem of prediction the time scales divergence error to a wide range of master clock generators. A mathematical model of the clock generation process for the generator under consideration is proposed. The model adequacy is demonstrated using simulation experiment and comparison with the results of measurements performed with the real generator. A method and algorithm of calculating the error of time scales divergence prediction are described, results of a test problem solution with the method are presented.
312
An approach to the problem of prediction of the extent of functional obsolescence of information system using a fuzzy regression model of degradation of the system functionality. Special feature of the approach is introduction of fuzzy time intervals and fuzzy expert assessments of the degree of functional (moral) obsolescence. Forecasting is carried out based on processing the results of fuzzy expert evaluation of the degree of functional obsolescence of the information system. Expressions allowing to determine the optimal values of the parameters of the fuzzy linear regression model, as well as predict the extent of functional obsolescence and functional residual resource of the information system, are presented. The application of the described results makes it possible to obtain predictive estimates of indicators of moral durability of existing information systems necessary for planning the processes of their design, operation, and modernization.

INSTRUMENTS AND SYSTEMS OF AUTOMATIC CONTROL

320
In terms of the bases of return sequences and their corresponding signatures for the backpacking problem, a class of binary return bases characterized by a slower growth compared to the binary ones is distinguished. The inclusion of bases in this class provides a departure from attack of reduction of the basis of Koester—Lagarias—Odlyzko and gives a packing density outside the interval (0,1). The constructions of such bases are employed to develope a symmetric block encryption algorithm that uses shared memory of sender and recipient in Shannon model of secret communication. The algorithm also uses the chaining mode of the ciphertext blocks and generates the corresponding hash function. An additive protocol for creating a symmetric key is given.
INFORMATION SECURITY OF AUTOMATED CONTROL SYSTEMS OF TECHNOLOGICAL PROCESSES Andreev Yury S, Andrey M. Dergachev, Fedor A. Zharov, Daniil S. Sadyrin
331
The modern principles of automatic process control systems (ACS-TP) design are considered, as well as the systems software and hardware components. Specific features of dispatch system characteristics of different generations of the ACS-TP implementation are analyzed. A review of existing threats and vulnerabilities in the field of information security of ACS-TP is presented. It is shown that the recent increase in computing power of ACS-TP elements is accompanied by an increase in unauthorized access to them using the Internet. A new security threat introduced by implementation of the Internet of Things protocols when working with visual data is described. A classification of the main measures aimed at protecting the automated process control systems is given, examples of regulatory documents governing actions to ensure information security and examples of software and hardware products aimed at their implementation are presented.

ELECTRONIC AND ELECTROMAGNETIC DEVICES

340
An experimental setup for measuring low and ultra-low electrical resistances is presented, method of performing measurements of samples resistance is described. The measuring method is based on the known principle of amperemeter-voltmeter. The novelty of the setup is the use of special gaskets made of highly oriented anisotropic pyrographite and installed between the current leads, measuring electrodes, and the sample under study. As a result, the contact electrical resistance at the interface "measuring electrode-test sample" is diminished, and parasitic thermopower is reduced to a negligible value. Along with expansion of the dynamic range of the setup in the area of low resistances, the measurement accuracy is improved up to 10 m. Results of measurements of the electrical resistivity of graphite rings used as heating elements of the high-temperature blackbody model of BB3500YY type are presented. An estimation of measurement error is given.
IDENTIFICATION OF ELECTROMECHANICAL PARAMETERS OF PRECISION ELECTRIC DRIVES Teresa Orłowska-Kowalska, Sergey Yu. Lovlin, Madina Tsvetkova, Abdullin Artur A, Mamatov Alexander G., Valery A. Guryanow
346
A method of identification of electromechanical parameters of the electric drive, based on the method of least squares, is proposed. The method solves the problem of automatic acquisition of experimental data under the conditions of speed and rotation angle limitation. Algorithm realizing the method can be automatically adjusted during its operation to achieve high accuracy of the estimated parameters. An algorithm for servo tracking telescope is presented as an example. The proposed algorithm may be of interest for designers of electromechanical systems with limited motion. Experimental verification of the results on a two-mass bench with variable stiffness coefficient and variable moment of inertia of the second mass was carried out.
USING SPACE-VECTOR PWM WITH VARIABLE MODULATION FREQUENCY IN MULTILEVEL INVERTERS OF PRECISION ELECTRIC DRIVE SYSTEMS Valentin S. Tomasov, Aleksander A. Usoltsev, Konstantin M. Denisov, Denis A. Vertegel
355
Pulsations of load current vector are investigated for various inverter control algorithms with the use of a mathematical model of five-level inverter. It is shown that space-vector modulation has a number of features that need to be taken into account when developing control algorithms aimed at minimization of current pulsations in a wide range of output voltage control. A disadvantage inherent in this modulation method is noted, which consists in an abrupt change in the magnitude of the current pulsations when switching from one modulation level to another, which can lead to resonance phenomena in the instrument drive. While the changes in the pulsations level of are inherent in all modulation algorithms, for sinusoidal PWM and PWM with third harmonic injection, the changes are shown to be significantly smaller and not so abrupt. Current pulsations as a function of the output voltage index are also investigated, and variable frequency modulation is shown to significantly reduce the range of variation of current vector pulsations and provide almost the same average value throughout the entire output voltage control range for all modulation algorithms. The result allows to consider the space-vector modulation as an alternative to sinusoidal PWM and PWM with third harmonic injection in a wide voltage control range. The effect of dead time on the dead zone of the inverter regulation characteristic and, as a result, on the control range of rotation velocity of the electric drive is investigated. An increase in the number of levels is shown to reduce almost proportionally the dead zone and thereby extend the control range.

OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

APPLICATION OF OPTICAL SENSORS IN CONTROL SYSTEMS OF TRAIN TRAFFIC Ephanov Dmitry V., German V. Osadchy, Valery V. Khoroshev
364
The problem of improvement of principles of management and control in railway transport is dis-cussed. The possibility of using optical sensors in railways traffic control systems instead of traditional electric current track circuits is considered. The way of installation and fastening of sensors to railway rails is described, as well as the principle of integration into the control system. A block diagram of the system for recording the parameters of moving units based on optical sensors is given. Results of experimental studies of sensors on Shushary railroad hump yard of October Railway are demonstrated. It is shown that optical sensors can be used not only for positioning of mobile units, but also for measurement of several critical parameters of the units. The results presented in the paper are regarded as a first step towards the transition to a fundamentally new method for controlling the movement of trains based on optical technologies.
IN VIVO STUDY OF HUMAN TOOTH ENAMEL USING COLORIMETRIC DEVICE Prokopenko Victor T., Majorov Evgeniy E., Ludmila I. Shalamay, Natalia E. Popova, Chernyak Tatiana A., Alexeу V. Kurlov, Dagaev Alexander V., Tsygankova Galina A.
372
A colorimetric device for measuring the color parameters of tooth enamel in normal and erosive state in therapeutic dentistry is developed. A block diagram of the colorimeter and the graphic representation of spectral sensitivity of the receiving part of the device are presented. Metrological capabilities of the developed colorimeter are analyzed with the use of results of measurement by a certified device. Results of carried out calibration of the colorimetric device and the data of test measurements of chromaticity coordinates of certified and cataloged glass show that the colorimeter can be used to control diffusely reflecting objects. In particular, the device can be used in therapeutic dentistry to examine in vivo human tooth enamel in various states. Characteristics of the test samples were determined near marked points to confirm the results authenticity.
379
The spectral method is developed for estimating the parameters of the point-spread function (PSF) in the problem of restorating the distorted (smeared, defocused) im-ages. The method is based on the analysis of a spectrum, or the Fourier transform (FT) of a distorted image. This method makes it possible to estimate the PSF parameters: the angle θ and magnitude Δ of image smearing, as well as the size  of the image defocusing spot. This enhances the image restoration accuracy. The smeared image spectrum is compressed in the smearing direction, and this makes it possible to estimate θ and Δ. The defocused image spectrum is also compressed, and more strongly, the larger the defocusing spot. A new estimates are obtained for the smearing parameters θ and Δ using the Nyquist frequency and for the defocusing parameter  using the Bessel function. The results of applying this method to image processing are presented. The developed technique can be used to enhance the accuracy of smeared and defocused image restoration via their mathematical processing by solving the integral equations.

SCIENTIFIC AND PRACTICAL DEVELOPMENTS

OPTIMIZATION OF HEAT-ACCUMULATING SYSTEM FOR COOLING ELECTRONIC DEVICE WITH HIGH-POWER SOURCES Gerasyutenko Victoria V., Vladimir A. Korablev, Dmitry A. Minkin, Alexander V. Sharkov
387
A liquid cooling system is improved by application of a heat-accumulating device. The modified cooling system consists of a heat accumulation unit, flash tank, pump that transfers coolant through the cooling channels, and radiator. Design of heat accumulation device is optimized with the use of developed thermal and mathematical models. The coolant temperature and the radius of the phase transition boundary in the melting substance are calculated. The condition under which the heat accumulator restores the absorption capacity is analyzed. Result of calculated design of heat-accumulating unit providing a thermal mode of device with power of 3 kW within 5 minutes is presented as a practical example. Recommendations are formulated for development and operation of thermal battery allowing to choose parameters and calculate the thermal regime of the liquid heat storage cooling system. Heat storage devices, allowing to significantly improve the weight and size characteristics of cooling systems, are regarded as highly effective means of ensuring the thermal regime of devices operating under severe external conditions.
393
A dynamic model of a piezoactuator is proposed, which accounts for the effect of non-rigidity of the base on the payload displacement. Application of the model makes it possible to evaluate the negative effect of deformations on the quality of the control system operation. The results obtained allow to perform parameter identification and system quality analysis using computer simulation tools. In the adopted scheme, provision is made for choosing measuring means of the system and, if necessary, correcting the control law to minimize the operating errors.

BRIEF NOTES

IMPROVEMENT OF AN ELECTROMECHANICAL DEVICE FOR MEASURING ROTATION ANGLE Vladimir A. Zinkov, Medunetskiy Viktor M. , Ozhiganov Aleхander A.
400
An electromechanical device designed to provide current information about angular position of an object, is presented. The device contains two units: a mechanical reduction gear and a rotary optical en-coder. To reduce the weight and size characteristics of the reduction gear, it is proposed to use a digital angle transducer based on a quasi-cyclic code scale. Improvement of the accuracy of measurement of rotation angle of the output link of the gear is achieved by reducing the backlash in the gearing due to the use of the cone-wedge of gear rims of the gear.
404
Methods of increasing the size of enlightenment area on the spherical surface of large-curvature optical element in a vacuum chamber are studied practically. Results of measuring the distribution of the energy reflection coefficient along the surface of an optical element of large curvature are presented, zone of enlightenment for a single-layer antireflection coating formed from different film-forming materials (MgF2 and SiO2) is determined.