Significant scientific and technical advances of recent times in the study of remote regions of the Universe, obtaining images of space and ground-based objects with high resolution became possible thanks to the use of new technologies for the development of large-size optical telescopes. A rise in the main telescope mirror diameter leads to an increase in mass and enhances the possibility of deforming the mirror surface and the telescope’s structural elements. This problem can be overcome by using segmented or flexible mirrors, the shape of which is maintained with the use of active optics. However, atmospheric turbulence degrades the quality of images of space objects obtained by ground-based telescopes. To compensate for the influence of the atmosphere, adaptive optics methods are used in most optical telescopes. An overview of the current state of optical telescopes development is presented. Consideration is given to large ground-based optical telescopes with composite and flexible mirrors with aperture diameter exceeding six meters, controlled by adaptive systems. The high resolving and penetrating capabilities achieved during the creation and modernization of large-sized ground-based optical telescopes allow to set and solve new and important scientific and applied problems in the study of space  objects of natural and artificial origin. One of these tasks, which has become particularly relevant in recent years, is the detection of small-sized fragments of space debris near spacecraft and orbital space stations. 

The method of virtual measurements of zenith distances of stars, constituting the basis of astronomical on-board system of autonomous navigation and orientation (ASANO) for spacecrafts (SC) included into lunar information and navigation support system (LINSS), is described briefly. The effects of errors in the stellar catalog, and errors in measurements carried out with optical-electronic devices on the accuracy of navigational calculations of SC, are analyzed. Characteristics of accuracy of various technological cycles in ASANO functioning are presented. It is noted that the system can be used as the main or backup contour of navigation and ballistic support for the LINSS space segment and other artificial satellites orbiting the Moon. A simulation model of ASANO functioning is created, the accuracy characteristics of the system are obtained by means of modeling, and the requirements for instrumental errors of measurement and accuracy of coordinates specified in the onboard catalog of stars are justified. 

The problem of estimation of the maximum error of complex system using the data, received before and after testing of prototypes, is considered. The method of experimented information priority is applied; the method allows to receive estimations, that are most accurate if the prior information does not contradict results of experiments. Analytical expressions are derived for a posterior estimate of the maximum error of complex system and for the gain in accuracy or number of experiments. An example of application of obtained test results is given. The resulting gain is shown to depend on the proximity of a priori and experimental information. The measure to determine the weights for a priori and experimental data is the likelihood ratio for testing the hypothesis of their homogeneity. 

The problem of measuring a helicopter altitude and flight speed, wind speed and direction, atmospheric pressure and density is considered. Measuring of helicopter movement parameters and environmental characteristics in the parking, starting, take-off and landing, and flight modes, using on-board means involves difficulties due to considerable air-dynamical disturbances caused by inductive flows in the vortex column of the rotor. An integrated system for measuring helicopter movement parameters and the state of the atmosphere relying on the information on the rotor vortex column is proposed. Functional diagram and algorithms of information processing in the integrated measuring system built on the base of stationary multifunctional on-board receiver are presented. It is noted that the use of single fixed on-board multifunctional aerometric receiver distinguishes the proposed system from traditionally employed measuring instruments and determines the broad prospects for the system application in helicopters of various classes and purposes. 

ПA technique of cyber security metrics visualization for support of decision-making process in risk analysis and countermeasure selection is proposed. This technique is used to select suitable visualization models for a predetermined set of security metrics or to create new specific models. A list of security metrics that characterize the network and its objects, indicators describing attacks on network objects and characterizing attackers is given, security incidents occurring in the system, countermeasures, and integral indicators of risk and choice of countermeasures reflecting the overall level of security and used for choice of protective measures are outlined, and a list of visualization models and their classification is presented. A developed software prototype of the visualization system based on the proposed method is presented. An example of the hierarchical creation of a custom model of visualization of security metrics of a corporate computer network based on the developed prototype is considered. 

The tasks of preventing the possibility of theft of credentials of privileged users and reducing the consequences of such theft in the domain network are considered. The problems associated with this task are studied. Ways to get the password hash of a privileged account by an attacker are analyzed, the risk of such theft when using a domain network is assessed. A solution is proposed that consists in building a layered (multi-level) protection, each subsequent level of which is built on the assumption that the attacker has overcome the previous protection level. An approach is proposed which consists in strengthening password protection and preventing the possibility of administration (remote and local) if an attacker has a privileged account data. The proposed approach is stated to provide a complete solution to the problem.  

In joint alignment of laser transmitting and receiving modules of an active laser optoelectronic device (laser locator, rangefinder or altimeter), an installation with a collimator is used. If the device field-of-view angle exceeds one degree, a lens collimator should be used for adjustment. When applied lens collimator is designed for a wavelength other than that of the laser emitter, the collimator aberrations lead to errors in determining centroids of the scattering spots in the focal plane and result in sighting error (direction-finding error). The effects of aberrations of a lens collimator with field-of-view angle of 8o are studied. After optimization of the collimator initially designed for the visible spectral range, the direction-finding error for the wavelength of 1064 nm is reported to decrease several times.   

A new method of performing high-precision measurements of absolute distance to reflecting object is described. The proposed principle of the measuring combines electronic method of determining distances and interferometric method of recording displacements using a meter of interference fringe fraction. A schematic diagram of proposed laser radio-interferometric meter is presented. The possibility of using changes in the length of the laser resonator and the visibility of the interference pattern in accurate long-range measurements is experimentally confirmed.

The problem of experimental identification of frequency response functions of precision electric drives of actuating axis of telescopes is analyzed. Several approaches to experimental estimation of frequency response functions based on Fourier transform are considered, including empirical transfer function estimation, Welch's averaged periodogram method, short-time Fourier transform. The influence of nonlinearity and harmonic distortions on the results of experimental identification of frequency response function (Coulomb friction, cable transition moment, torque ripples and cogging torque of PMSM, dead time of the PWM inverter) is studied. An experimental scheme with a torque loop and a switched controller of the angular velocity and position, which used to limit the angular velocity and position and to provide the permanent sign of angular velocity for reducing the impact of Coulomb friction is described. Approbation of the proposed approaches to the identification experiment was carried out in MATLAB environment using mathematical model of electric drive with two-mass load and experimental data on distortions and nonlinearities obtained while tuning the telescope actuation axis. 

A two-dimensional array of densitometric parameters obtained by processing tomographic medical images of patients with verified diagnoses of lung diseases (cancer and tuberculosis) is analyzed. The possibility of using information about the properties of contours of lung spherical formations is investigated. A technique for constructing contours of such formations based on the analysis of digitized medical images is applied. A mathematical method introduced for describing the contour is based on calculating the conditional center of mass of the image of the pathology and obtaining two one-dimensional signature functions, a module of the radius vector drawn from the center of mass and its polar angle, as functions of the conditional number of the pixel belonging to the contour. Using the spectral analysis of digitized medical images, such characteristics of the contours of the formations under investigation as the spectral entropy of the contour, multiplicity, and the number of local maxima, are calculated. Analysis of statistical difference of these characteristics for different types of diseases (cancer and tuberculosis) was carried out. It is shown that several studied characteristics of the contours are statistically different and therefore enable differential diagnosis of lung disease. 

The influence of the depth of anisotropic etching of silicon in KOH solution on the surface roughness is studied experimentally. Wire etching of silicon wafers at various depths was followed by measurement of roughness parameters with the PF-60 optical profilograph. It is shown that such parameters of surface roughness as Ra, Rz, Rmax vary with the depth. To improve the surface quality and reduce the above parameters, chemical polishing in an isotropic etchant was used. It is argued that the studies carried out have practical significance for the manufacture of silicon structures of micromechanical systems. 

Arterial hypertension (AH) manifestation and development is associated with many endogenous and exogenous factors. A dynamic population model of AH development in different time scales with consideration of personalized treatment strategies is presented. The overall dynamics of the hypertensive patient group using a demographic model is created. Simulation of AH development at the individual level, is performed with the use of clustering the patients array based on data stored in electronic health records. For patients from each group, models of variability of the quantitative characteristics of the patient's digital profile were developed and the probabilities of the development of concomitant pathologies were estimated. A model is constructed of antihypertensive treatment tactics and strategy using a classifier predicting the most effective class of drugs for the patient based on his/her digital profile individual components collected before the treatment initiation. The developed simulation technology can be used to optimize the health care system processes, primarily for outpatient care, to estimate the effectiveness of new drugs and treatment strategies introduction, and to simulate scenarios for new clinical guidelines introduction. 

The methods of rapid signal processing using fractal analysis are investigated. An algorithm for preprocessing of data presented in the form of one - and two-dimensional signals on the example of MRI images and cardio signals is proposed. The obtained results are claimed to serve as a basis for application of fractal analysis in the processing of medical signals on large samples with subsequent statistical analysis.