### INFORMATION TECHNOLOGIES AND SYSTEMS

AREA PREDICTION OF LAUNCHER DETACHABLE ELEMENT FALL BASED ON MEASURED DATA
Nikolay F. Averkiev, Dastanbek A. Bulekbaev

3

The problem of accuracy improvement of area prediction of launcher detachable element fall is considered. An approach to refinement of model of detachable element movement is proposed based on the use of data obtained with measuring instruments along the space apparatus launch rout.

TEST POLYNOMIALS OF GORDON—MILLS—WELCH SEQUENCES
Victor G. Starodubtsev

7

An algorithm of Gordon—Mills—Welch sequences building up is proposed. The algorithm is based on the use of structural properties of finite fields with double expansion.

FRACTAL ANALYSIS OF BRAIN TOMOGRAMS
Виноградова А. А., Anna O. Kaznacheeva, Musalimov Victor M

14

The fractal analysis application for quantitative estimation of object structure is studied. Results of Hurst parameter calculation for magnetic resonance images of brain are presented. The distribution parameters are evaluated, and probability intervals are estimated. Stochastic modeling carried out for the normal and the uniform distributions reveals specific features of Hurst parameter used as a diagnostic indicator.

TRENDS IN SCIENCE AND TECHNOLOGY PROGRESS IN THE FIELD OF SERVERS MANUFACTURING FOR DATA CENTERS
Yury L. Leokhin, Igor N. Dvoretsky

20

Analysis of server equipment market is presented; comparative analysis of servers’ characteristics is carried out using the production of largest manufacturers as an example. The main tendencies in research and development of the server equipment manufacturing for data-centers are formulated.

PARALLEL SOLUTION OF THE HARTREE–FOCK PROBLEM FOR GRAPHENE MOLECULE: SCALABILITY AND HYPEREFFICIENCY
Svitenkov Andrey, Dmitry Spelnikov, Maslov Vladimir G, Boukhanovsky Alexander V

25

A method of parallel solution of Hartree–Fock problem based on DC algorithm is considered. Calculation of the self-consistency problem solution is partly carried out with local processors to minimize the computational time.

### INSTRUMENTS AND SYSTEMS OF AUTOMATIC CONTROL

NEURAL NETWORK CONTROL SYSTEM OF NONLINEAR DYNAMICS OF BUCK CONVERTER
Alexey I. Andriyanov, Nikita A. Krasnov

33

A design of neural network control system of buck converter based on direction-to-target method is presented. With the system, given nonlinear dynamic properties of the converter are maintained.

PHASE LOCKED LOOP SYSTEM SYNTHESIS FOR THREE-PHASE ACTIVE VOLTAGE RECTIFIER CONTROL SYSTEM
Abdullin Artur A, Polyakov Nikolay A

38

Phase locked loop system synthesis method is described in terms of state space formalism. Implementation of synthesized phase locked loop system in three phase active voltage rectifier control system allows to compensate for reactive power component and to correct current shape in mains.

ACCURACY PARAMETERS OF A NONLINEAR LINK FOR SELF-OSCILLATORY ACCELEROMETER
Sergey V. Luchko, Sergey Yu. Baluev, Mikhail A. Vatutin, Yury A. Kuzmichev, Klychnikov Alexey I., Vitaly P. Efimov

43

The effects of deviation of radioelement parameters from their nominal values on accuracy of measurements with pendulum accelerometer in self-oscillatory operation mode are considered. Recommendations for minimization of the effects are formulated.

### HEAT REGIMES AND RELIABILITY OF INSTRUMENTS AND SYSTEMS

ANALYSIS OF EFFICIENCY OF INFRARED IMAGERS DATA CORRECTION
Sergey M. Borzov, Victor I. Kozik, Artem S. Feoktistov

47

Comparison of various methods of test bench calibration of infrared imagers is carried out and stability of the imagers’ parameters is estimated. Correction procedure performed just after calibration is shown to allow for high quality of images.

A METHOD FOR CALCULATION OF NON-STATIONARY TEMPERATURE OF SPACE OBJECT ON A CIRCULAR ORBIT
Yulia Bayova, Lapovok Yevgeniy V., Hankov Sergei I.

51

A formula for energy balance of spherical space object with uniform temperature is derived with the account for the orbit altitude and slope. The proposed approach incorporates evaluation of integral coefficients of the object exposure to the Earth infrared radiation and solar radiation reflected by the Earth. A mathematical
model for calculation of non-stationary temperatures of the object in transition between shadowed to sunilluminated orbit segments is presented.

### INSTRUMENT-MAKING TECHNOLOGY

IMPROVEMENT OF LASER THERMOCHEMICAL RECORDING ON THIN CHROMIUM FILMS USING REPEATED PROCESSING
Elena Shakhno, Dmitry A. Sinev

57

A method for improvement of spatial resolution of planar structures produced by repeated local laserinduced oxidation of thin chromium film and subsequent etching is investigated theoretically.

NONREGULAR DIFFRACTION GRATING FOR LASER LINE GENERATOR
Balya Vera K, Denisyuk Igor Yu, Elisabeth B. Sheklanova, Nadezda Vorzobova

61

Manufacturing of diffraction grating of “battered” period for laser line generator is analyzed. The method under consideration is based on nano-imprint replication of master sample made by laser engraving of thermosensible film. Optical characteristics of the obtained diffraction optical element are measured.

### BRIEF NOTES

UNCERTAINTY ANALYSIS OF PREDICTION MODELING OF COMPLEX SYSTEMS: DATA UNDERSTANDING AND ENSEMBLE TECHNOLOGIES
Ivanov Sergey V, Boukhanovsky Alexander V

66

Combined application of data understanding methods and ensemble technologies to uncertainty analysis of prediction modeling of complex systems is discussed using the problem of St. Petersburg flood prevention as an example.

DESIGN OF HARMONIC SIGNAL GENERATION BLOCK OF DIGITAL SIGNAL PROCESSING CIRCUIT IN FIBER-OPTIC HYDROPHONE
Plotnikov Michael Yurievich, Ivan Deyneka

68

A method of harmonic signals generation using Chebyshev polynomials is proposed for the digital signal processing circuit in interferometric-type fiber-optic hydrophone. Realization of the method with a field programmable gate array was developed and tested.