### SYSTEM ANALYSIS, CONTROL, AND INFORMATION PROCESSING

SYNTHESIS OF SELF-CHECKING COMPUTING DEVICES
BASED ON A COMPLETE SYSTEM OF SPECIAL GROUPS
OF THE DIAGNOSTIC OBJECT OUTPUTS
Ephanov Dmitry V.

355

Features of concurrent error-detection circuit synthesis for a known diagnostic object structure are discussed. A complete set of special groups of outputs that characterize them by some diagnostic parameter is presented. Separation of special groups of outputs allows to select a code for building an integrated control circuit, taking into account the possibility of detecting errors with a specific multiplicity and a certain type. A method for constructing an integrated control circuit is proposed, which involves an analysis of all subsets of the diagnostic object outputs, their classification by belonging to any special group of outputs, as well as the subsequent coverage of all outputs by special groups with the choice of the best coverage method by the criterion of structural redundancy, indicating specific codes to control the calculations. The proposed method is assumed to be effective in several cases of organizing built-in control circuits and to allow synthesizing a self-checking device even when this cannot be achieved by using the duplication method.

STATIONARY CHARACTERISTICS OF GI/G/1/1 QUEUING SYSTEM
IN TERMS OF THE RENEWAL PROCESS
Aleхey I. Peschansky

373

The semi-Markov process describing queuing system operation is analyzed as a renewal. Its regeneration points are the moments of requests arrivals to the free system. Formulas are established for calculating the following characteristics of the system for a regeneration cycle: average numbers of incoming, serviced and lost requests; average residence time of the system in the free state; average total sojourn times in the system for one and two claims. The final probabilities of the system physical states, average stationary sojourn times in the states, in the queue and in the system are expressed in terms of the renewal process characteristics.

OPTIMIZATION OF PROCESSES IN CYBER-PHYSICAL SYSTEMS
Tatiana V. Avetisyan, Yakov E. Lvovich, Andrey P. Preobrazhensky

389

The features of solving problems related to the optimization of information transfer processes in cyber-physical systems at manufacturing enterprises are considered. A multi-stage process of making an optimal decision on the formation of a cyber-physical system is presented, the use of which makes it possible to overcome the difficulties associated with the large dimensions of the analyzed problem. Conditions imposed on the controlled parameters are revealed. A set of restrictions in the system is presented. A block diagram of the process of making an optimal decision reduced to a certain procedure, is given. A principle of constructing a generalized efficiency criterion is shown. A set of extremal problems used in the course of a cyber-physical system analysis is formulated. On the basis of a system of functional equations presented in the form of recurrent relations, realization of the optimality principle is demonstrated. The features of costs distribution by resources in a cyber-physical system are considered and an example of the rational use of modular capacities in the overall structure of the system is given. The results of mathematical modeling are presented to demonstrate the possibility to increase the efficiency of the data transmission process.

TWO-LEVEL AND MODULARLY TWO-LEVEL QUASI-ORTHOGONAL
WALSH-STRUCTURED MATRICES FOR IMAGE MASKING
Alexander M. Sergeev

399

A separate class of quasi-orthogonal matrices, namely, two-level Mersenne matrices structured according to Walsh, are studied. The difference between the systems of orthogonal Hadamard–Walsh and Mersenne–Walsh functions is shown. Modular two-level Mersenne–Walsh matrices and their portraits are considered. A system of functions constructed using a modularly two-level Mersenne–Walsh matrix has twice as many levels as a system of functions constructed on the basis of a two-level Mersenne matrix structured according to Walsh. As an applied problem using structured quasi-orthogonal matrices, the procedure for masking images with two-level and modularly two-level Mersenne-Walsh matrices with an assessment of the results of masking - destruction of the original image is considered. The example of a test image demonstrates the change in the brightness histogram and the influence of the order of the masking matrix on the masking result.

### OPTICAL AND OPTO-ELECTRONIC INSTRUMENTS AND SYSTEMS

RELIABILITY OF DUAL-AXIS SCANNING HEADS USED IN ADDITIVE MANUFACTURING
Yury I. Shanin, Ilya S. Sharapov

409

A dual-axis scanning system ("scanner") intended for use in additive production and selective laser melting of metal powders is presented. The scanner consists of three independent nodes - a collimator, a scanning head and an F-theta lens, connected to each other. The purpose of the work was a brief review and calculation and experimental justification of the main technical solutions taken in terms of ensuring the reliability of the scanner at the stage of design development and issuance of working design documentation. In accordance with GOSTs for reliability, analysis of the circuit design and reliability requirements is carried out, causes of possible failures of the scanner during operation and possible limit states in its operation are considered, calculations are presented to substantiate the health of the scanner both during operation and in storage and transportation conditions. Thermal calculations of the collimator, scanning head, and F-theta lens are carried out. The influence of low (during storage) and high (during operation) temperatures on optical components of the design is also considered. Strength calculations, including those based on the finite element method using the ANSYS software, are performed for scanning mirrors installed in the scanning head and subjected to high angular accelerations. Results of the study testify the reliability of the elements and the scanner as a whole. A method for calculating the reliability of the scanner is proposed. Measures recommended for making changes to the design in order to increase its reliability are outlined. The developed recommendations are implemented in the process of a prototype scanner manufacturing.

OPTIMIZATION TECHNIQUE FOR A TIME-OF-FLIGHT OPTICAL TURBIDIMETER
Natig H. Javadov , Fakhraddin G. Agaev , Bibikhanym R. Jabbarli

423

The issues of optimizing a fiber-optic time-of-flight optical turbidimeter are discussed and the conditions for its optimal operation with sensitivity being the optimization criterion, are determined for both conventional and distributed implementations. An optimization technique is proposed: for the usual case, expressions are obtained for the optimal relationship between the measurement time on the receiving fiber of the light signal emitted by the transmitting fiber, counted from the pulse start moment, and the distance between the transmitting and receiving fibers; for the distributed version of the implementation of the turbidimeter, the conditions for the extreme operation mode are determined. The technique can be applied in advanced water quality control systems.

### INSTRUMENTS AND METHODS FOR MONITORING THE NATURAL ENVIRONMENT, SUBSTANCES, MATERIALS AND PRODUCTS

EXPERIMENTAL MEASURING SYSTEM
FOR CONTROL OF AIRCRAFT HULL SURFACES
Majorov Evgeniy E., Gennady A. Kostin, Chernyak Tatiana A.

430

A measuring system for monitoring aircraft hull surfaces is studied experimentally. Results of experimental research into the measurement range, the output signal amplitude, as well as the measurement error are presented. A comparative analysis of the results of experimental measurements and independent measurements performed with a certified instrument is carried out. The dependences of the averaged amplitude of the output signal on the distance of the output signal from the optical pupil to the surface under investigation during the controlled object movement, as well as on the light beam diameter at the object surface, are obtained.