Subject of Research.The paper presents theoretical and experimental analysis of dependence of the determination error of a modulated optical signal under intense background illumination on the value of mutual shift of two current-voltage characteristics if using a double synthesized aperture on multiscan position-sensitive detector. Method. The studies have been carried out on a specially designed setup, that allows scanning photosensitive area of multiscan position-sensitive detector by an optical beam that imitates intense solar illumination. At the same time the position error of determination of weak modulated optical signal coordinate is measured at different relative position of signal and background illumination, and background power. Main Results.Experimental studies have confirmed the theoretical conclusions. It is shown that the use of double synthesized aperture of multiscan position-sensitive detector with the voltage shift of the current-voltage characteristics equal to 0.4 V enables to reduce position determination error of a weak modulated signal by an order of magnitude. Practical Relevance.Research results have opened the opportunity of accuracy increase for position-sensitive systems operating under background illuminations exceeding the level of information optical signal.

 Subject of Research. A mathematical model of optical breakdown in the dielectric liquid droplets when exposed to pulsed laser radiation was developed. The process is considered in several stages: heating, evaporation of the particle, forming a steam halo, ionization of the steam halo. Numerical study was carried out on the basis of the mathematical model to determine the threshold characteristics of the laser pulse. Main Results.Distributions of pressure, density and temperature of the particle steam halo were obtained by means of a calculation. The temperature field around the liquid droplet was determined. It has been found that at high energies in the gas bubble, the conditions are provided for thermal gas ionization and start of the electron avalanche, leading to plasma formation. Due to the volumetric heat generation, the droplet is overheated and is in a metastable state. The plasma cloud is almost opaque to radiation that causes an abrupt increase of temperature. As a result, an explosion occurs inside the droplet with the formation of a shock wave that is propagating outward. Practical Relevance.The results can be used to assess the performance of high-power laser scanning (LIDAR) under the presence of liquid droplets in the atmosphere and other suspensions. Lasers can be used in fire and explosion aerospace systems. Obtained findings can be applied also in the systems of laser ignition and detonation initiation.

Subject of Research.  The paper deals with application of quaternions for optimization of reflector parameters at autocollimation measurements in comparison with a matrix method. Computer-based results on the quaternionic models are presented that have given the possibility to determine conditions of measurement error reduction in view of apriori information on the rotation axis position. The practical synthesis technique for tetrahedron reflector parameters using found ratios is considered. Method. Originally, received conditions for reduction of autocollimation system measurement error are determined with the use of a matrix method for definition of an angular object position as a set of three equivalent consecutive turns about coordinate axes. At realization of these conditions the numerous recalculation of orientation parameters between various systems of coordinates is necessary that increases complexity and reduces resulting accuracy of autocollimation system at practical measurements. The method of quaternions gives the possibility to analyze the change of an absolute angular position in space, thus, there are conditions of accuracy increase regardless of the used systems of coordinates. Main Results. Researches on the mathematical model have shown, that the orthogonal arrangement of two basic constant directions for autocollimator tetrahedron reflector is optimal with respect to criterion of measurement error reduction at bisection arrangement of actual turn axis against them. Practical Relevance. On the basis of the found ratios between tetrahedron reflector angles and angles of its initial orientation parameters we have developed a practical method of reflector synthesis for autocollimation measurements in case of apriori information on an actual turn axis at monitoring measurements of the shaft or pipelines deformations.

 Subject of Research.The paper proposes an original method for studying the parasitic effects in the electro-optic modulator of the fiber optic gyroscope. Proposed method is based on the usage of a special waveform phase modulation signal. Method. The essence of the proposed method lies in modification of serrodyne modulation signal, thereby providing a periodic displacement of the phase difference signal to the maximum of the interference curve. In this case, the intensity level reflects the influence of parasitic effects with the degree of manifestation being determined by the sequence of voltage control signals applied to the modulator. Enumeration of combinations of control signals and the corresponding intensity levels gives the possibility to observe an empirical dependence of the parasitic effects and use it later for compensation. Main Results. The efficiency of the proposed method is demonstrated by the program model of the fiber optic gyroscope. The results of the method application on a production sample of the device were obtained. Comparison with the results of direct estimate of the parasitic intensity modulation effect testifies to the effectiveness of the proposed method. Practical Relevance. The method can be used as a diagnostic tool to quantify the influence of parasitic effects in the electro-optic modulator of the fiber optic gyroscope as well as for their subsequent compensation.

 We consider combined control in automatic control systems for technological objects trajectory  movements. We present research results of the system disturbance invariance ensuring on the example of the technological manipulator that implements hydrocutting of the oil pipelines. Control is based on the propositions of the fourth modified invariance form with the use of bootstrapping methods. The paper presents  analysis of results obtained by two different correction methods. The essence of the first method lies in injection of additional component into the already established control signal and formation of the channel for that component. Control signal correction during the signal synthesis stage in the control device constitutes the basis for the second method. Research results have shown high efficiency of application for both correction methods. Both methods have roughly the same precision. We have shown that the correction in the control device is preferable because it has no influence on the inner contour of the system. We have shown the necessity of the block usage with the variable transmission coefficient, which value is determined by technological trajectory parameters. Research results can be applied in practice for improvement of the precision specifications of automatic control systems for trajectorial manipulators. 

 A problem of stabilizing for the multirotor unmanned aerial vehicle in an environment with external disturbances is researched. A classic proportional-integral-derivative controller is analyzed, its flaws are outlined: inability to respond to changing of external conditions and the need for manual adjustment of coefficients. The paper presents an adaptive adjustment method for coefficients of the proportional-integral-derivative controller based on neural networks. A neural network structure, its input and output data are described. Neural networks with three layers are used to create an adaptive stabilization system for the multirotor unmanned aerial vehicle. Training of the networks is done with the back propagation method. Each neural network produces regulator coefficients for each angle of stabilization as its output. A method for network training is explained. Several graphs of transition process on different stages of learning, including processes with external disturbances, are presented. It is shown that the system meets stabilization requirements with sufficient number of iterations. Described adjustment method for coefficients can be used in remote control of unmanned aerial vehicles, operating in the changing environment.

 Subject of Research.We present results of structural and dielectric study of organic ferroelectric 2-methylbenzimidazole (MBI) thin films. Method. The films have been grown on substrates of leuco-sapphire, fused and crystalline silica, neodymium gallate, bismuth germanate, gold, aluminium, platinum. The films have been grown by two different methods: substrate covering by ethanol solution of MBI and subsequent ethanol evaporation; sublimation at the temperature near 375 K under atmospheric pressure. Crystallographic orientation studies have been performed by means of «DRON-3» X-ray diffractometer, block structure of the films has been determined by «LaboPol-3» polarizing microscope. Small-signal dielectric response has been received with the use of «MIT 9216A» digital LCR-meter, while strong-signal dielectric response has been studied by Sawyer-Tower circuit. Main Resuts. We have shown that the films obtained by evaporation are continuous and textured. Obtained film structure depends on the concentration of the solution. Films may consist of blocks that are splitted crystals like spherulite. Spontaneous polarization components in such films may be directed both perpendicularly and in the film plane. We have also obtained structures consisting of single-crystal blocks with spontaneous polarization components being allocated in the film plane. Block sizes vary from a few to hundreds of microns. Films obtained by sublimation are amorphous or dendritic. The dielectric properties of the films obtained by evaporation have been studied. We have shown that the dielectric constant and dielectric loss tangent increase under heating. The dielectric hysteresis loops are observed at the temperature equal to 291-379 K. The remnant polarization increases with temperature for constant amplitude of the external electric field, and achieves 4.5mC/cm2, while the coercive field remains constant. We propose that such behavior is explained by increase of the number of crystallites with switchable polarization due to decrease in the coercive field under heating. The remnant polarization decreases with frequency increase. Practical Relevance. Proposed method of ferroelectric films manufacture is characterized by low cost and convenience. Unlike many other ferroelectrics, the films contain no lead and rare metals. MBI films demonstrate the low value of the coercive fields. This paper may be useful for electronic components developers.

Subject of Research.The paper deals with study of Raman spectra and luminescence spectra in the visible region of the sodium-germanate glass: 49 GeO2 – 13 Na2O – 27 Yb2O3 – 11 La2O3 - 0,25 Er2O3  and presents research results. In addition, this glass is doped with 5 mol% of the following components MgO, BaO, Al2O3, PbO, Nb2O5, TiO2, SiO2, P2O5 in order to study the effect of these additives on the structure of the glassy matrix and the anti-Stokes luminescence spectra of erbium ions. Method. Raman scatteringspectra were recorded by Renishaw inVia Raman Microscope. Excitation source is a helium neon laser (λ= 633 nm) with power equal to 50Wt. Anti-Stokes luminescence of erbium ions was registered in spectral region of 450–750 nm at room temperature (excitation laser wavelength is 975 nm, power is 1Wt). Main Results. It was shown that the structure of the initial glass does not change with the introduction of niobium as Nb2O5 in any coordination plays a role of network forming, building a single mixed grid with tetrahedrons [GeO4]. Introduction of the second glass former P2O5 leads to loosening germanate structure due to the appearance of the phosphate sublattice. This leads to a redistribution of the relative intensity of up-conversion luminescence bands with maxima at 540 and 670 nm compared with the initial glass. Introduction of additives PbO, MgO, Al2O3, TiO2 results in a multicenter structure. In case of titanium oxide addition it leads to a change in the relative intensities of the erbium luminescence. 

The paper proposes solution for the problem of Open Data integration and geocontext markup in LBS-platform. Solution method is based on providing unified platform-level interfaces for executing modular and reusable Open Data import instruments. The method was implemented as an extension for the popular Geo2Tag LBS-platform. The solution gives the possibility to satisfy developer requirements for import subsystem: import performance is on the same level as a typical client requests to platform and import objects are accessible using platform data manipulation interfaces. Sources or executable files of import instruments can be published in an open access for the other LBS-platform users that enables to reuse of these instruments and combine them into libraries. Plugin for Open Data import from "Open Karelia" (museum overlay of Geo2Tag) was implemented as a practical application of proposed method. The paper also contains description of load testing of the method implementation which demonstrated that import plugin provides high performance level in case of the parallel tasks number less or equal to the number of processor cores. Further increase of parallel tasks leads to significant decrease of performance, which still keeps predictable enough. Proposed method is applicable for the wide range of LBS-platforms because it has no reference to any specific LBS-platform features. Solution makes it possible to reach significant competitive advantage for LBS platform and its services because the method overcomes «cold start» problem for LBS. It is achieved by the use of Open Data as an initial content for LBS.

Subject of Research.The paper deals with the algorithm of anomaly detection in the behavior of operating system processes caused by the execution of previously unknown parts of the program code. The algorithm is implemented in the novel intrusion detection system CODA. A testing algorithm allows reducing test time and increasing its accuracy. Method. The proposed detection method is based on creation ofbehavior model for legitimate process using sequences of system calls. Measures of similarity between an arbitrary process and a model are proposed. They allow interpreting the problem of anomaly detection as the problem of vector classification. In order to evaluate the accuracy of the anomaly detection algorithm, the accuracy of the classifier is proposed to be evaluated by cross-validation method. Neural network of perceptron type was used as a classifier. Main Results.A platform for the mass distributed testing of malicious programs in virtual machines was developed. Open source library for distributed computing BOINC was used in the platformimplementation. Academic base of malware and open base Malwr was used to select 60 thousand malicious programs. From the general base33.13% of malware have workedcorrectly. A model of legitimate processes runningwithin half an hourwas created. Estimates ofmalware behavior were recorded as vectors. The most accurate neural network was searched for these vectors classification. Neural networks with different teaching parameters and different number of neurons in a hidden layer were looked over. The most precise perceptron was discovered. The accuracy of the best classifier was 91%. Practical Relevance. The results can be useful in malware detection. Our algorithm does not require Internet connection.It can find both old and new malware. 

Subject of Research. The paper deals with the effectiveness of multipath transfer of request copies through the network and their redundant service without the use of laborious analytical modeling. The model and support tools for the design of highly reliable distributed systems based on simulation modeling have been created. Method.  The effectiveness of many variants of service organization and delivery through the network to the query servers is formed and analyzed.  Options for providing redundant service and delivery via the network to the servers of request copies are also considered. The choice of variants for the distribution and service of requests is carried out taking into account the criticality of queries to the time of their stay in the system. The request is considered successful if at least one of its copies is accurately delivered to the working server, ready to service the request received through a network, if it is fulfilled in the set time. Efficiency analysis of the redundant transmission and service of requests is based on the model built in AnyLogic 7 simulation environment. Main Results. Simulation experiments based on the proposed models have shown the effectiveness of redundant transmission of copies of queries (packets) to the servers in the cluster through multiple paths with redundant service of request copies by a group of servers in the cluster. It is shown that this solution allows increasing the probability of exact execution of at least one copy of the request within the required time. We have carried out efficiency evaluation of destruction of outdated request copies in the queues of network nodes and the cluster. We have analyzed options for network implementation of multipath transfer of request copies to the servers in the cluster over disjoint paths, possibly different according to the number of their constituent nodes. Practical Relevance. The proposed simulation models can be used when selecting the optimal design solutions for the redundant transmission and maintenance of requests time-critical for stay in information and communication system.

We propose a traffic management system for autonomous vehicles that are agents at the intersection. In contrast to the known solutions based on the usage of semiautonomous control systems in assembly with the control unit, this algorithm is based on the principles of decentralized multiagent control. The best travel plan for intersection passage is produced by means of optimization methods jointly by all agents belonging to a dynamic collaboration of autonomous vehicles. The order of road intersection optimal for a given criterion is determined by the agents in the process of information exchange about themselves and environment. Our experiments show that this protocol can reduce significantly the traffic density as compared to the traditional systems of traffic management. Moreover, the effectiveness of the proposed algorithm increases with increasing density of road traffic. In addition, the absence of the critical object, that is the control unit, in the control system, reduces significantly the effectiveness of possible failures and hacker attacks on the intersection control system.

The paper deals with questions of protection against unauthorized access to the data transmitted between unmanned aircraft vehicle (UAV) and ground control station (GCS). This is due to the fact that standard instruments of network security sometimes provide security of not enough proper level or do not satisfy the restrictions connected with the features of UAV: limited computing resources of the UAV on-board computer and real-time operation. We have offered to use Vernam cipher (one-time pad) as an additional measure for data protection. Vernam algorithm combines such advantages as theoretically proved absolute cryptographic security, ease of implementation, high speed of encryption and low processor load. It is especially important for large volumes of data encryption (e.g. video information). Within the bounds of experimental researches the technique is used based on cryptographic gamma of block cipher GOST 28147-89 in the Cipher Feedback Mode for a one-time pad generation. Application of Vernam cipher means the deletion of used one-time pad pages. The replacement of used one-time pad pages by cipher text is proposed for assurance of the above-named requirement and for simultaneous computer memory saving. It gives additionally the opportunity not only to save key sequences but also to accumulate encrypted data in the on-board computer memory. Realization of the offered method allows increasing the data protection level without engaging large computing power and memory capacity.

A calibration technique for cryogenic temperature sensors is proposed and implemented. The experimental setup is based on the helium cryogenerator, providing calibration of the temperature sensors of various types in wide temperature range, including cryogenic band (25-100K). A condensation thermometer with hydrogen, neon, argon and xenon as working gases is used as a reference sensor. The experimental setup was successfully used for precise (0.1K precision) calibration of platinum resistive temperature detectors (Pt-100) for international nuclear physics experiments MuSun and PolFusion. The setup can also be used for calibration of temperature sensors of the other types.

The paper presents research  results of fractal properties of microplasma noise at LED avalanche breakdown in the visible spectrum (λ= 660; 700  nm).  The breakdown type of p-n-junctionwas determined as a result of measured current-voltage characteristics at room temperature, at the temperature of 100-105 °C and after cooling down to room temperature. It was shown that the breakdown of avalanche type is realized in the majority of LEDs. It was established that the partial avalanche breakdown mode may be realized in LEDs, when a small current flows in pulses through the device. By increasing the voltage, pulse amplitude increases, closely spaced pulses merge, and time intervals between them are reduced. To interpret experimental results we applied model of processes occurring in microplasma, and noise model of partial and advanced avalanche breakdown (by A.S. Tager). The study revealed previously non-described features of microplasma noise – the fractal nature of microplasma noise. The algorithm for fractal dimension calculating was implemented in MATLAB. The dependence of fractal dimension on the reverse voltage applied to the LEDs was found out. Obtained fractal signal can be applied in optical communication systems for noise free and confidential information transmission.

A prerequisite for the use of intelligent control methods, including algorithms of fuzzy logic, is increasing complexity  in all industries, especially when parameters of technical systems while in operation vary in wide range. The paper provides comparative analysis of the basic types of common fuzzy direct action controllers on the example of speed control system in the DC motor drive. Design features of these types of fuzzy controllers are shown.  Their comparison with traditional PI controller is carried out through the use of simulation, including the conditions of uncertainty expressed in changing of equivalent moment of inertia of the motor shaft. As a result, the conclusion about the feasibility of fuzzy PID-type controller application is made. The features of fuzzy controllers outlined in the paper can be summarized to more complex motor drive systems and to other non-linear systems that require the maintenance of any parameter within a given range.

The paper deals with the idea of a research method for hierarchical multilayer routing systems. The method represents a composition of methods of graph theories, reliability, probabilities, etc. These methods are applied to the solution of different private analysis and optimization tasks and are systemically connected and coordinated with each other through uniform set-theoretic representation of the object of research. The hierarchical multilayer routing systems are considered as infrastructure facilities (gas and oil pipelines, automobile and railway networks, systems of power supply and communication) with distribution of material resources, energy or information with the use of hierarchically nested functions of routing. For descriptive reasons theoretical constructions are considered on the example of task solution of probability determination for up state of specific infocommunication system.  The author showed the possibility of constructive combination of graph representation of structure of the object of research and a logic probable analysis method of its reliability indices through uniform set-theoretic representation of its elements and processes proceeding in them.

The Brownian dynamics method has been used to study the effect of the branching asymmetry on the local orientational mobility of segments and bonds in dendrimers in good solvent. “Coarse-grained” models of flexible dendrimers with different branching symmetry but with the same average segment length were considered. The frequency dependences of the rate of the spin-lattice relaxation nuclear magnetic resonance (NMR) [1/T1H(H)] for segments or bonds located at different distances from terminal monomers were calculated. After the exclusion of the contribution of the overall dendrimer rotation the position of the maxima of the frequency dependences [1/T1H(ωH)] for different segments with the same length doesn’t depend on their location inside a dendrimer both for phantom models and for models with excluded volume interactions. This effect doesn’t depend also on the branching symmetry, but the position of the maximum [1/T1H(ωH))] is determined by the segment length. For bonds inside segments the positions of the maximum [1/T1H(ωH)] coincide for all models considered. Therefore, the obtained earlier conclusion about the weak influence of the excluded volume interactions on the local dynamics in the flexible symmetric dendrimers can be generalized for dendrimers with an asymmetric branching.

Subject of Research.  We present research results for numerical modeling possibility of discharges in gas mixtures within the modern model of nonlocal plasma by creation a sequence of plasma-chemical and numerical models and comparing the results with experimental data. Method. Creation method for series of models with gradually increasing complexity has been used. It is based on a step by step expansion of the range accounted for elementary processes in nonlocal glow discharge plasma in the air. The air is approximated by the mixture of nitrogen and oxygen at low pressures under conditions suitable for experimental verification. For each iteration of plasma chemical scheme, corresponding numerical models of gas-discharge were created. The graphs of the discharge gap electrical parameters on the pressure were obtained by this method. Theoretical data obtained at each step have been compared to the experimental data and the results of previous computer models. Main Results. The model has been created  that provides a good agreement with the experimentally obtained dependencies of the voltage drop across the discharge gap on the gas pressure in the areas of normal and abnormal glow discharge. By the updated model the optimum value for the coefficient of secondary electron emission from the cathode was chosen. Additionally, we have obtained the spatial distribution of the internal parameters of nonlocal plasma (longitudinal and transverse profiles of the electric potential, electron and ion densities, the electron temperature) as a subject to further experimental verification. Practical Relevance. The created models are perspective to be used for diagnosis and the setting of parameters of micro-discharges in the air. They have different applications, including developing method of electronic collision spectroscopy (CES) gas mixtures.

Subject of Research. Algebraic Bayesian networks are referred to a class of probabilistic graphical models that are a representation of knowledge bases with uncertainty. The distinguishing feature of ABN is the availability of global structures. Among them there are primary and secondary structures that are directly used in various kinds of probabilistic logical inference as well as tertiary and quaternary involved in the problems of automatic synthesis and identification of the properties of the secondary structure and partially in the machine learning tasks within specified networks. Existing algorithms for quaternary structure changing require its complete rebuild when changing the primary structure. That feature slows down the whole global structures synthesis, dispels user’s attention who is forced to re-analyze the whole rebuilt structure instead of focusing on the changes that were directly caused by the limited modification of the original data. This fact reduces ABN attractiveness as a model for data processing in general. Scope of Research. This paper is aimed at speeding up the rebuild process and eliminating the shortage of the quaternary structure rebuild algorithms when adding and deleting vertices of primary structure expressed in excess rebuild of the entire structure. The task of algorithm incrementalization for quaternary structure rebuild is solved to achieve the goal. Method. The proposed approach is based on the properties of incremental algorithms that reduce the amount of computations due to the result obtained at the previous step of the algorithm. All the arguments used in the paper are expressed in a graph theory language to apply the established system of terms and classical results. Main Results. The paper presents incremental and decremental algorithms, complemented by a proof of correctness and listing. Given algorithms are based on the previously obtained incremental algorithms for tertiary structure. Moreover, a detailed analysis of the plurality of separators is carried out on each stage of the algorithms. Theoretical and Practical Relevance. These algorithms develop a global structure of algebraic Bayesian networks as well as the theory of probabilistic graphical models in general. Furthermore, they create the groundwork for creation of the secondary structure invariants that may be non-unique even if the primary structure is fixed unlike the current approach where connections are included in the secondary structure. The deletion of manipulation with a set of secondary structures considerably simplifies and makes foreseeable visualization of such complex object as ABN and may improve the computational characteristics of probabilistic logical inference algorithms. It also enables to reformulate the problem of ABN machine learning excluding any need for synthesis of many different objects with complex structure and virtually the same semantics. It also can be expected that the obtained incremental algorithms will accelerate computational processes of rebuilding and properties analysis for all four global ABN structures.

The paper proposes a method for identification of axial moment of inertia of the mechanical system called reaction wheel pendulum with a viscous friction in the bearings of the suspension. The method is based on the reversible symmetric motions. Pendulum system motion includes a free measured motion and reverse symmetrical motion at the same angular interval. The pendulum includes a rod with a low-power DC motor with a flywheel attached to the end of the rod. The angle of rotation and velocity of the rod and the flywheel are measured by encoders. The paper introduces a new method,presents a design formula,a mathematical model of the pendulum system and a robust motor control law for it. The method is based on energy algorithm and control residing in electric motor operational changes by means of a flywheel. The mechanical system moves symmetrically that is provided by nonuniform controlled flywheel rotation. As a result, the influence of dissipative factors on identification results is eliminated. Dynamic modeling is carried out for the pendulum system and proves high accuracy of the method. The research results can be used for identification of complex mechanical systems under the action of resistance, dissipative and other forces.

 The paper presents simulation results of hydrostatic bearing dynamics in spindle assembly of standard flexible production module with throttled circuit. The necessity of dynamic quality increase for automatic control system of the hydrostatic bearing with the use of correcting means in the form of RC-chains is shown. The features of  correction parameters choice coming from the existence of the crossing connections in automatic control system structure are noted. We propose the block diagram of automatic control system of the hydrostatic bearing in Simulink working field and cyclic algorithm for determination program of RC-chain parameters implemented in MATLAB taking into account typical thermal processes for the finishing treatment. Graphic-analytical method for the correction parameters choice is presented based on the stability stock phase gradient for dynamic quality determination of automatic control system. Researches of the method estimability in case of using the standard metal bellow valve as the hydrocapacity for RC-chain are also carried out. Recommendations for the bellow valve choice are formulated. The check of dynamic quality indicators concerning transition processes calculated by means of the appropriate programs developed for MATLAB is performed. Examples are given for phase stability factor gradient schedules with partition of various areas of hydrostatic bearing dynamic quality for different frequencies of spindle rotation and procedure description of data cursor function application on  MATLAB toolbar. Improvement of hydrostatic bearing dynamics under typical low loadings for finishing treatment is noted. Also, decrease of dynamic indicators for high loadings treatment in case of roughing treatment is marked.

Subject of Research. Decision-making model is offered for informational and educational systems. The study of multi-criteria model is carried out taking into account knowledge, reaction and doubt. Method. The model of material proficiency by the user is based on identification of the personal characteristics when operating with the system. As a result of personal characteristics tracking in the system, an image is formed for each user that can be used for identifying his state: knowledge level, proportion of error, handwriting information, etc. During registration the user is passing an input test. Multi-criteria test results are automatically stored in the user's personal database (agent matrix) and accounted for psychological comfort, formation of the next system content, management of knowledge levels, decision-making when working with the system. The proposed method gives a more clear and "transparent situational picture" for objective decision-making. Main Results. Implementation of multi-criteria decision-making model contributes to the quality of distance education. Also, the method makes it possible to reduce the probability of guessing the correct answer, thus increases the objectivity of knowledge level evaluation in diagnostic systems for management of learning process based on remote technologies. Practical Relevance. Obtained theoretical results of the work are used in training systems on the basis of multi-criteria decision models. Thus, the proposed model leads to an increase in the average score of about 0.3-0.4 points and reduces the training time in 1.5 to 2.0 times.

 We consider the problem of calculating chromaticity coordinates estimates of triangle vertices gamut for displays with maximum area of color reproduction. Initial data for the evaluation are tabulated data on the shape of the spectral locus interpolated by Bezier splines. Research results are chromaticity coordinates of the triangle vertices gamut maximum area specified on the color chart according to the standards of the International Commission on Illumination.

Methods for gene set enrichment analysis, widely-used for analysis of gene expression data, were studied. A problem of cumulative calculation of enrichment statistic was considered. For this problem an algorithm based on square root decomposition heuristic was developed. An asymptotic run-time complexity of the algorithm was found. Practical implementation showed an order of magnitude increase in performance compared to a naïve algorithm when run on typical input sizes. The developed algorithm can be used to improve significantly the performance of gene set enrichment analysis.

The paper deals with the results of probabilistic model development for behavioral computer network. We present a method for the system state simulation immediately after the attack. To describe the threats we have selected an appropriate set of mathematical models for processes. The authors have proposed a modification of the attack trees theory including probabilistic attack trees, describing the ways to achieve objectives by illegal intruders and calculating the probability of the various types of threats. The proposed method enables to assess the levels of risks and vulnerability of the studied networks with the aid of the system behavior simulation.

The model of information infrastructure control for small pedagogical system including virtual machines is presented. Particular models of pedagogical system parameters are defined within the control model; the usage of risk model and application possibility of software technical quality model are justified. The key events (decision points) are highlighted in describing the life cycle of infrastructure control. The set of methods and algorithms supporting decision-making in the framework of a small pedagogical system is proposed. In order to illustrate the applicability of the generated solutions the main results of the experiments are presented.