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

INFORMATION TECHNOLOGIES AND SYSTEMS, COMPUTER TECHNIQUE

879
The problem of managing a specialized cloud computing system performing heterogeneous resource-intensive tasks is considered when methods of the task execution can be represented as an arbitrary sorting out of a large number of options. Data-based parallelization of tasks under uncertainty is analyzed. To solve the problems of scheduling incoming input streams of tasks, the simulation is performed using the SimEvent/Simulink/MatLab software package. The functioning of the system and especially servers, represented as finite state machines, is analyzed. The peculiarity of the proposed model is the possibility of interrupting the server when an external signal appears. Using the developed server model makes it possible to improve system performance by saving time for each server to complete tasks and more efficiently distributing tasks between the servers of the entire system.
887
Results of research on development of an analytical model of data transmission algorithm that implements temporary access to a radio network resource and technologies for the formation of wide-band signal-code structures are presented. The application of a unified information distributed system with temporary access separation in the context of the use of radio channels for the transmission of packet data is described. A method of estimating the noise immunity of a radio line is considered based on obtained analytical functions that allow for a probabilistic assessment of the correct reception of a sent message in a pre-nondeterministic data transmission environment with a variable level of interference. The perspectives of using the developed analytical models to build promising data transmission systems based on radio are postulated. The possibility of application of obtained results in simulation modeling to solve the problem of providing the necessary level of broadband communication is analyzed.

INSTRUMENTS AND SYSTEMS OF AUTOMATIC CONTROL

896
Combined control in a digital tracking system is considered for the first order astatism and time delay in the direct circuit, which allows to fully compensate for both the speed and acceleration errors. A method for calculating the digital tracking system with a delay is proposed, which excludes an increase in transients oscillation when working out jumps of the driving force caused by compensation of the velocity error. The transfer function of the coupling by the setting effect is determined, compensating for the velocity error and the acceleration error. Impossibility to reduce overshoot by reducing the gain in the direct circuit when compensating for both errors is established, and the causes of this phenomenon are clarified.
909
A control system developed for liquid heat exchanger in hop extract production is presented. A robust controller based on the sliding mode method and the full-order Luenberger observer is implemented. A comparative analysis of this method and the PID control method using pulse-width modulation under conditions of disturbances, noise and quantization of measurements is carried out. Simulation results confirming the advantages of the proposed approach are presented.
METHOD FOR DETERMINING A SPECIAL OPTIMAL CONTROL Vladimir P. Ivanov , Tyugashev Andrey A.
916
The issues of synthesis of optimal terminal control of a nonlinear dynamic system are considered when the control is not on the boundaries of the maximum allowable set of values and linearly enters the mathematical model of the system. In this case, equating to zero the partial derivatives of the Hamiltonian with respect to the control leads to the requirement of zeroing the corresponding Lagrange multipliers. But then, on the formal side, any control satisfies the optimum condition, that is, the optimal control cannot be found in the traditional way. The problem of finding a special control arises. A method for finding a special optimal control is known, but its implementation is associated with the features of solving a nonlinear boundary value problem. Therefore, another method of determining a special optimal control is proposed, based on the sequential differentiation of the condition of the first row of the singularity. The result obtained must satisfy both necessary and sufficient optimality conditions. Illustrative examples are presented.

OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

925
The problem of measuring the thickness of transparent low-scattering and low-absorbing layers of inorganic coatings and films in the range from 0.1 mm to 0.6 mm in real time with a relative measurement error of less than 10% is considered. The measurements are performed using a combination of two methods – laser interferometry and modified triangulation. The subject of the study is to determine the set of parameters necessary for measuring the thickness by the specified optical methods; the purpose of the study is to develop a way to measure the thickness by the combined method so that the refractive index of the sample under study is absent in the set of necessary parameters. The principle of operation when using the combined method is presented and the search for optimal parameters of the measuring installation is carried out, which allows to reduce the measurement error to 5% while reducing the information content of the measurement by 3 times only. The main advantage of the proposed approach is that information on the numerical value of the refractive index of the measured layer is not required to determine the thickness by the combined method.
933
Principle optical schematics of the source with the possibility of spectral adjustment are analyzed. None of the existing tunable sources allows simultaneous rearrangement of the number of spectral lines, their position, and the half-width of a separate spectral line. Such spectral rearrangement is possible with the use of acousto-optic filtration together with a broadband radiation source. At the same time, the features of the acousto-optic filter cause the system low efficiency (5% or less), which limits the use of such a source, for example, in the spectral analysis of highly absorbing media. The choice of a schematic diagram of a broadband source interface system with an acousto-optic filter also affects the efficiency of the circuit and determines its additional characteristics - the complexity of components and dimensions. Results of simulation of the system operation performed using the optical design software Zemax Optical Studio, are reported to be in good agreement with the results of the experiment.
SILICON PHOTOELECTRONIC MULTIPLIERS AS A BASIS FOR CREATING COMBINED SENSORS Ivan R. Gulakov, Andrej O. Zenevich, Olga V. Kochergina, Evgeny V. Novikov
941
The possibility of constructing combined sensors based on silicon photoelectronic multipliers is analyzed. The influence of temperature and supply voltage of silicon photoelectronic multipliers on changes in dark current, sensitivity to optical radiation and critical illumination is investigated. An installation for carrying out the research under consideration is proposed. Experimental samples of Si-photomultiplier tubes (Si-PMTs) with a p+-p-n+ structure produced by JSC Integral (Republic of Belarus), as well as serially produced silicon photomultipliers Ketek PM 3325 and ON Semi FC 30035 are studied. It is shown that the temperature dependence of the dark current for these Si-PMTs has a linear form. The temperature increase is found to decrease the sensitivity of silicon photomultiplier tubes to optical radiation. The value of the critical illumination for Si-PMT is shown to increase with increasing temperature. Based on results of the performed studies, a structure of combined sensor based on silicon photomultiplier tube is proposed, allowing for simultaneous control over the two parameters, temperature and illumination. Main characteristics of this sensor are evaluated.

INSTRUMENT-MAKING TECHNOLOGY

INFLUENCE OF STRUCTURAL FEATURES OF CONSTRUCTION POLYMER-COMPOSITE MATERIALS ON THE PHYSICAL AND MECHANICAL PROPERTIES OF PRODUCTS Abramchuk Mikhail V., Medunetskiy Viktor M. , Svetlana Yu. Perepelkina, Surikov Dmitry G.
949
A brief overview of construction polymer-composite materials with an indication of their main properties is presented. It is noted that these materials are advisable to use in the manufacture of products of complex shapes, in particular gears with a complex configuration of gear rings. Results of experiments with structural polymer materials to study their characteristics of friction and tensile strength, carried out using the universal friction machine MTU-1 and SHIMAZU AGS-500X machine, are presented. Samples of polymer parts are made using FDM technology. Presented graphs showing dependence of the friction coefficient and ultimate tensile strength on the filling factor of polymer samples, are to be taken into account in the design and manufacture of parts.