Models of computer system use for the system reliability assessment are proposed. The models account for a single-stage procedure of processor equipment recovery and a two-stage reconstruction procedure of memory subsystem: first the hardware and then codes and data. The restoration of software and data, followed by entering relevant information in recovered memory, is realized under control of the processor and therefore may be accompanied by equipment failures, the CPU as well as the memory; during the equipment recovering held at the idle computer, any failures are excluded.

The problem of information security is interpreted as a problem of reservation of threats of information system vulnerabilities by threats of vulnerabilities of the information security system. The approach allows assessing and modeling the threat characteristics and the reliability parameters of protected information system. Requirements to development of a valid threat attacks Markov models with discrete states and continuous time are formulated.

A method is proposed for improving the efficiency of multimedia data compression standards. To improve the efficiency of entropy coding within the standard, the hierarchical enumerative coding (HEnuC) is used, including the coding method of Lynch-Davisson (LD) and enumerative coding of bounded integers (EBI). Experimental study of the proposed solutions is performed using MatLab package for several images. The presented results demonstrate better compression than achieved with the simple entropy coding (Huffman method). The developed approach is recommended for the use in telecommunication systems for storage, transmission, and processing of multimedia data.

The existing approaches of desktop virtualization are analyzed to develop recommendations on the choice of method of virtual personal workplace presentation. To compare the types of virtual desktops, various criteria are employed such as usage of disk space storage, waiting time at the beginning of a session, the possibility of modification by a user, centralized service of the workplace, the ability to work with graphics without having to install special server graphics cards. As a result of the comparative analysis of desktop virtualization methods, a new method of construction of virtualization system for desktop virtualization is proposed.

A robust suboptimal control solution of the speed control is proposed for multi-agent systems described by nonstationary nonlinear differential equations with uncertain parameters, disturbances, communication delay, and possible information constraints in the measurement channels. To compensate for disturbances, the method of auxiliary loop method is used with the loop presented by a parallel reference model for each agent. Classical methods of optimal control are used for speed control, and therefore calculation of optimal control may be carried out with the use of standard packages of existing software, e.g. MatLab. Simulation results are presented to demonstrate the effectiveness of the proposed scheme under uncertainties, delay, and information constraints. The results show that the control accuracy can be improved by increasing the gain in the control law, reduce the high frequency gain in the auxiliary loop, and increase the feedback gain of the observer.

A new structural scheme is proposed for the system, providing robust control for object with delay in control with compensation of slowly varying disturbances. Based on an internal model of the object at each moment the system output response to a disturbance is estimated. Instead of a predictor, in the control loop a special tracking is implemented; the signal comes to the nominal system input, and the disturbance compensation is provided by control response generated by the tracking system. The proposed scheme allows to reduce the system sensitivity to parametric uncertainty of the object model and the delay magnitude.

A brief description of design of spectrographs, located stationary on the Nasmyth focus platforms of the 6-meter telescope. The spectrographs with crossed dispersion NES and Lynx (where the crossed dispersion is provided by diffraction gratings) are considered, as well as the medium-resolution spectrograph (the crossed dispersion is obtained with a prism) and the classical diffraction spectrograph (MSS). These spectrographs can be relatively quickly prepared to observations as for the main scientific program and as a backup device. To measure circular and linear polarization in stellar spectra it is necessary to accumulate a large signal to ensure sufficient spectral resolution. The necessity of calibration to be to performed to account for instrumental effects is noted.

Results of experimental study of heating of the optical elements made of high-purity quartz glass (Russian-made brand KS-4V) with radiation of high-power CW fiber laser are presented. Maximum temperatures of optical element at various power densities of the radiation are measured. The possibility of extrapolating the obtained results to power optics made of quartz glass of other brands produced in Russia and abroad (KU-1, Suprasil 300, and SK-1300) is discussed.

The actual problem of modern metrological maintenance in optical technologies related to highprecision control of the radius of curvature and shape parameters of optical mirrors is discussed. A comparative analysis of technical characteristics of modern interference systems and optical-electronic devices based on wavefront sensors such as Shack — Hartmann (SHWFS) is presented. An original circuit solution for development of a modernized functional diagram of the interference control equipment based on wavefront sensor (OEDWFS) for measuring optical surface curvature radius is described. A new highprecision method for control of curvature radius of surface mirrors with a permissible error of the measurement less than 0,01 % of the nominal value is proposed and scientifically justified. An analysis is given of the output parameter of the functional circuit of the DWF-based instrument — the limiting radius of the recorded wavefront.

Variants of multi-axis platforms used in devices for object micro-positioning are analyzed. A microscope XY-stage with parallel kinematic and piezoelectric drive based on bimorph actuators is recommended. Results of experimental study of the XY-stage are presented and conclusions are formulated.

Peculiarities of development and realization of graduate programs in the field of optical design are analyzed. Partnership between ITMO University (Russian Federation) and Warsaw University of Technology (Poland) is considered. The partnership is based on integration of high-qualified teaching staff, application of innovative educational technologies and accumulation of out-of-date infrastructure resources. A significant part of the educational program is reserved for the research and practice of students to ensure that results of the learning correspond to rapidly changing requirements of the labor market. Modularity, adaptability and variability of the structure of educational programs aimed at the formation of individual trajectories of training.

A parallel algorithm for modeling random Boolean network (RBN) evolution with the use of the GPGPU technology is described. The influence of constraints on the length of attractors in modeling evolution is analyzed. Distribution of attractors length and the values of the average vertex outdegree for critical adaptive RBN derived with the use of proposed algorithm are presented.