Asymptotic and algorithmic properties of sparse backpack cryptosystems, providing the packing density outside the interval (0,1), are determined in terms of basis of finite-order recurrent sequences. Design of such cryptosystems is used to construct a block cipher in blocks engagement mode. Results of analysis of speed and statistical properties of the encryption algorithm as compared to the known standards of block cipher are presented.

Experiments on generation of applications flow in imitation models are carried out to deduce a combination of distribution laws for time intervals between applications correlated with real traffic in a computer networks. An imitation model of computer network is built in the Any Logic environment. The time of packet transmission in the channel is taken for a continuous random variable, and various laws of distribution of continuous random variable are used while configuring the model. Description of one of developed solutions for the traffic modernization is presented; based on proposed combination of the exponential, the uniform, and Weibull distribution laws, the deviation of the simulated flow from the real traffic is reduced from 40 to 6 %.

The problem of structural-parametric optimization of system for uninterruptible power supply of responsible consumers is considered. Mathematical models of the problem are developed. An economic criterion (minimization of capital investment or the annual cost) is taken for the optimality criterion, while required level of power supply system reliability with the account for redundancy of the uninterruptible sources is considered as the constraints. The dependence of the efficiency coefficient for parallel-working static uninterruptible power supply units from their load is investigated. Based on analysis of methods of discrete optimization problem solution, the method of "branches and limits" is justified. A developed computer program for solution of the problem is presented. As an example, the problem of the structural and the parametric optimization of the uninterruptible power supply system for specific initial conditions is considered. 

Processes of suppression of technical means for interception of side electromagnetic radiation by DVI standard interface are considered. A mathematical model is proposed for the side electromagnetic radiation arising from operation of raster information display systems. An imitation model for evaluating the active noise system impact on technical mean of interception of side electromagnetic radiation is presented.

An improved procedure for numerical compensation of thermal drift for fiber-optic gyroscope in real-time operation of the device is developed. The main idea of the proposed approach lies in the assumption of dependence of the thermal drift of the gyroscope on temperature, its first and second derivatives with respect to time. The correction procedure is performed individually for each fiber-optic sensor based on the data of field tests. The procedure of search of the necessary calibration coefficients is described, modernization of the iterative prediction algorithm and compensation of thermal drift of fiber-optic gyroscope is carried out. It is shown that application of the correction procedure makes it possible to achieve an essential reduction in thermal drift of fiber-optic gyroscope. The results of the comparative analysis of the new and the old algorithms to compensate for drift are presented.

Application of antenna lattice with optimized vector of weight coefficients for external interference suppression with antenna diversity signal receiver in radio-channel with fading is considered.

Metrological characteristics of a prototype of primary piezoelectric converter made of non-metallic material are studied. Mathematical methods are used to derive the conversion function of mass liquid flow into oscillation frequency as well as the developed converter sensitivity. Experimentally obtained dependencies of the metrological characteristics on the mass flow rate and transition process duration for water, milk, beer, and antifreeze-40 are demonstrated. The main sources of methodological errors for the converter are considered, and dependence of the absolute error on the mass flow rate of the water is presented.

The Echelle spectrograph PFES and a new-generation spectrograph ESPRI developed by considering the last achievements in optics and electronics are presented. In the new primary focus spectrograph for the BTA, diameter of the collimated beam, the echelle blaze angle, the lens focal length, and the CCD format are enhanced. Each of the ESPRI parameters (spectral resolution, the length of the concurrently measured spectral range, penetrating power) is at least twice as large as that for the PFES spectrometer. In spectroscopy mode, the spectral resolution is R=30 000, in the measurement mode for linear and circular polarization R=20 000. The new device enables fast transformation of the Spectro-polarimeter into the spectrograph, and vice versa. Schemes of the spectrographs PFES and ESPRI and presented, their characteristics are analyzed. Examples of echelle-spectra images are demonstrated.

Features of computer-aided design systems (CAD) for electronics and mechanical engineering Altium Designer and Autodesk Inventor, using the IDF intermediate data format, are discussed. Organization of the CAD systems collaboration, with one of the basic requirements of duplex data transfer is considered. For example, import and export of printed circuit board project is performed in two ways: via standard functions of both systems and with the use of integrating plug-in IDF Modeler. Results of comparative analysis of two methods using IDF format are presented. Comparison is also carried out of IDF and Step formats, advantages and shortcomings of the formats are analyzed. The proposed methods are said to be applicable for printed circuit board design in Altium Designer and in subsequent development of mechanical component of the electronic device in Autodesk Inventor.

Approaches to the problem of optimization of executive tool trajectory in CNC equipment used for laser treatment of complex-shaped surfaces are considered. Time of processing is used as the main optimization criteria. Two principal time shortening methods are proposed — by increasing in processing speed using smooth aliasing of acceleration/deceleration curves, and by minimizing the quantity of auxiliary passes. A genetic algorithm with crossover (similar to the one used to solve the traveling salesman problem) is proposed to reduce the number of auxiliary paths

Conception of ontological dictionary as a method of knowledge formalization and development of expert systems for design of technological process in instrument parts manufacturing is discussed. General principles of knowledge representation in the additive manufacturing are described. Considerable attention is given to the place occupied by ontological dictionary in multi-agent design system.

Prospects of applying ion-plasma and beam technologies (IPBT) to the production of cardan-less electrostatic gyro rotor with the high geometric accuracy and complex of functional parameters are considered. Technical solutions to the problem of formation of the moment of inertia of the spherical rotor and adjusting its imbalance by spraying the coating on the rotor surface with variable thickness and by local laser evaporation of point mass are proposed. Mathematical models for the management of the main rotor’s functional parameters based on the use of IPBT are presented. The results of the practical application of the developed models are demonstrated.

The problem of noise component of data obtained with electrophysiological study of gastrointestinal tract is considered. A method of quality data control in electrogastroenterography records based on analysis of high-frequency components of measuring signals is presented. A quantitative indicator of measuring signal quality is proposed, the indicator may be used directly during the measurements recording. A positive effect of the proposed method as applied to measurement of gastric contractions rhythmicity is demonstrated.

The problem of improving detection probability for PIR detectors is reviewed. A method based on creation of several directional diagrams optimized for various intruder models is described. Multi-element pyroelectric sensors and corresponding multi-channel signal processing are proposed.