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

INFORMATION TECHNOLOGIES AND SYSTEMS

291
Currently the problem of energy depletion attacks on modern wireless Internet-of-Things devices becomes increasingly important. While latent to attack targets and their monitoring systems, such attacks can exhaust the energy resource of the device in a fairly short period and thereby disrupt its operability and availability. Possible types of energy resource depletion attacks are analyzed. A generalized model of an intruder conducting attacks of this type are proposed, experimental studies are carried out using two developed software and hardware simulation stands with hardware and software devices based on Android 5.1 and Digi XBee v2 platforms.
298
A methodical approach to estimation of operation effectiveness of information system with temporary redundancy is proposed. Probability of successful implementation of the information system task is taken for the functioning efficiency index.  An integral equation based on the theorem of total probability is used for quantitative estimation of the probability. The Laplace transform is used to solve the integral equations. Analytic expressions are obtained for the probability density of the excess time, the values of the first and second initial moments, the variance and the standard deviation. An approximate formula is used for the inverse transition from the Laplace image of the obtained solution to the time domain. The amount of information work performed by the system with temporary redundancy is estimated. A distinctive property of the proposed approach is accounting for results of monitoring the information system functioning.

INSTRUMENTS AND SYSTEMS OF AUTOMATIC CONTROL

MODIFIED METHOD FOR PARAMETERS ESTIMATING IN FINITE-TIME CONTROL SYNTHESIS Zimenko Konstantin Alexandrovich, Polyakov Andrey E., Efimov Denis V., Kremlev Artem Sergeevich
304
A modified method for estimating parameters used in finite-time control synthesis is proposed. The object under the control is a chain of consecutively connected integrators in the presence of external disturbances and parametric uncertainties. It is assumed that the state vector is available for measurement. Results presented in the previous papers of the authors are extended. The developed method does not require the execution of additional computational procedures, such as the search for parameters on a certain numerical grid and allows to obtain the estimates of the necessary parameters analytically. Thus, the presented method is reported to simplify considerably the synthesis of a finite-time regulator.
309
Digital following systems with calculation devices providing a low speed of mismatch evaluation characteristic for automated control systems of industrial process of first generations. An increase in the rate of change of the driving influences requires an improvement in dynamic accuracy of the DCS of the support-rotary devices. A radical means of increasing dynamic accuracy is the elimination of the speed error and errors in the acceleration of the MSC. It is shown that an effective increase in the dynamic accuracy of the automatic control system of the automated process control system is possible to achieve without significant changes to the MSC itself, with the help of the control for the mastering signal being processed according to the proposed algorithm. The possibility to obtain a high quality of transient processes in a closed loop is demonstrated, while at a low rate of error calculation it is impossible to achieve low oscillation of the transient processes caused by jumps of the driving force.

COMPUTER TECHNIQUE

317
A technique for synthesis of various complex discrete linear systems on the base of differential equations for continuous analog filters is considered. The systems include low and high frequency filters, vibrational links, rejection and selective filters.  To derive the difference equations describing the operation of synthesized linear systems, the derivatives of differential equations are replaced by their analogs in the form of complex difference equations. With the correct choice of discretization period, the frequency properties of synthesized discrete filters coincide practically with the frequency properties of the respective continuous filters. Specific examples of design of complex discrete filters of low and high frequencies using the method of invariant selective differential equations are presented. 
323
Characteristics of weight-based code with summation without the operation of carries to the detection of errors in self-checking circuits of built-in test of logical devices of automation and computer tech-nique are analyzed. It is shown that in the case when the described code uses a sequence of weight coefficients forming a natural series of numbers, it ensures detecting of any single and double errors in data vectors. For this indicator, the proposed code is comparable to the classic Hamming codes but has more simple functions describing check bits. For some values of data bits number, the new code has the number of check digits one less than the classic one. This makes it possible to organize self-checking circuits of built-in control for logical devices with reduced structural redundancy in comparison with both duplication and using Hamming code for these purposes. The characteristics of error detection by types (unidirectional, symmetrical or asymmetrical) and multiplicities are better for a Hamming code identifying more errors at the logical device output than with the use of the proposed weighted code. Experiments carried out with the systems of benchmarks LGSynth`89 and MCNC Benchmarks confirm the theoretically obtained patterns. 

OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

BROADBAND ANTIREFLECTIVE COATING BY THE METHOD OF MOLECULAR LAYER DEPOSITION Khoa Fam Van, Phi Thai Ngo, Gubanova Lyudmila Alexandrovna
336
The potentialities of a new method of optical interference coatings — the method of molecular layer deposition – are considered. The method allows for constructing structures with the layers thickness of several tens of nanometers. In the research, experimental determination of the refractive indices is performed for the two materials used for formation of broadband antireflection coating — silicon dioxide SiO2 and aluminum oxide Al2O3. A technique is presented for analysis of antireflection coatings satisfying one or more of given conditions. Such coatings can be formed from symmetrical or asymmetric cells. The resulting coatings have a low reflectance in the wavelength range 420—820 nm, and the average reflectance values of symmetric and asymmetric multilayer systems in the wavelength range comprise 1,18 and 0,78 %, respectively. It is shown that asymmetric systems usually provide a greater possibility of enlarging the enlightenment zones than symmetric systems. The effect of thickness deviations on antireflection coating properties s analyzed for the given spectral range. It is established that the molecular layer deposition method makes it possible to create low reflective coating for the wide spectral range while reducing the size of the interference system.
342
Results of pilot studies of changing the characteristics of optical sensors of the spacecraft movement control system under the impact of external destructive influences of thermal and mechanical nature are presented. An analytical description is derived for dependencies of the sensor characteristics deter-mining the accuracy of the retention of the angular position of the spacecraft irrespective of the change in optical parameters of its elements, which allows to determine the maximum permissible levels of the influencing factors. The choice of the object of experimental research is substantiated and its constructive-functional scheme is presented. The problems of experimental research are formulated, the experimental procedure is presented, and the graphs of the output control signal versus the angular position are plotted based on the results of the experiments and simulations. 
COMPENSATION OF ERROR CAUSED BY INHOMOGENEOUS AIR PATH IN THE CONTROL SYSTEM OF REFERENCE MARKS SPATIAL POSITION Elena A. Sycheva , Korotaev Valery Viktorovich, Anton Maraev, Alexander Timofeev
348
The effect of vertical temperature gradient in the air on spatial position of active reference marks measurement accuracy is investigated for the case when the marks are mounted on an object controlled by an optical electronic system. To compensate the effect of air medium inhomogeneity, application of the dispersion method is proposed. Interrelation of control accuracy requirements and system parameters is shown. Accuracy of dispersion difference evaluation is estimated experimentally. A condition is derived for system parameters choice based on minimization of non-excluded error component.  
APPLICATION OF FIBER AND THERMAL-SENSITIVE ELEMENTS IN SECURITY AND FIRE ALARM SYSTEMS Kozlov Aleksei S., Labkovskaya Rimma Ya., Tkalich Vera L., Pirozhnikova Olga I.
356
A series of new magnetically controlled commuting devices for security and fire alarm systems, including fiber-optic and terbium-metallic elements, has been developed. These devices allow expanding the operational and functional capabilities of the element base of automation devices designed for use in modern security systems. The tasks solved by this series of devices include also the expansion of the logical capabilities, increasing the sensitivity, increasing the service life and ensuring the stability of the contact resistance of the switching devices. The devices can be used in development of fire and burglar alarm sensors operating at rated currents of 10 A and higher, as well as in circuits with increased switching power. A modified optical microphone is considered that performs the functions of fire alarm in shipborne optical communication systems. The estimation of static and dynamic errors confirmed the increase in reliability of these devices in comparison with analogues. 

SCIENTIFIC AND PRACTICAL DEVELOPMENTS

360
The process of internal thread surface ion-plasma nitriding of nut, which is a part of nut-roller screw, is considered. Ion-plasma nitriding is used to harden the surface layer of a part after machining, this allows to obtain a surface of the required quality without additional grinding required when traditional methods of bulk hardening are applied. Technological regimes are selected, and additional requirements are imposed on the workpiece material during nitriding of threaded surfaces that, as a rule, are not subjected to surface hardening treatment. The complex of developed constructive and technological measures provides the resource of the roll-screw transmission more than five times higher than that of the models presented in the world market, with a significant reduction in the cost of production due to the elimination of long and expensive grinding processing from the technology.  
368
Results of studies of mechanical stresses that occur in the sensitive element of micro-pressure sensor when it is mounted in the package are presented. The finite element method is used to numerically simulate both the residual mechanical stresses of the sensitive element crystal and the stresses caused by thermal expansion-compression, when the sensitive element crystal is placed in the system which binds support crystal and package. The optimal design of support crystal, which includes both two-dimensional and three-dimensional temperature compensator elements, is found to allow for minimizing stresses caused by temperature fluctuations. Among the considered types of support crystals, the ones that do not add additional negative functional in the output characteristic during sensitive element operation are selected, and a design that is easy to manufacture is chosen. An appropriate model of support crystal that is applicable for sensitive element sensor of both the absolute and differential pressure is proposed. 

BRIEF NOTES

374
A block diagram of the simulation model of a pedestrian navigation system that implements integration of inertial sensors measurements and of corrective information from the biomechanical model of pedestrian motion is presented. The composition and content of the computational procedures of the model are briefly described. 
377
Issues of improving flexibility of technological lines due to the extending of working zones of indus-trial manipulators are considered. A method is proposed for extending the working zone of manipulator, wherein the manipulator is mounted on a fixed base surface.