Summaries of the Issue
TRENDS IN THE DEVELOPMENT OF DETONATION ENGINES FOR HIGH-SPEED AEROSPACE AIRCRAFTS AND THE PROBLEM OF TRIPLE CONFIGURATIONS OF SHOCK WAVES. Part II - Research of counterpropagating shock waves and triple shock wave configurations Bulat Pavel V, Denissenko Petr V.
The paper deals with current issues of the interference theory development of gas-dynamic discontinuities as applied to a problem of propulsion refinement for the air-spacecrafts, designed for hypersonic flight speeds. In the first part of the review we have presented the history of detonation study and different concepts of detonation engines, as well as air intakes designed for hypersonic flight speeds. The second part provides an overview of works on the interference theory development for gas-dynamic discontinuities. We report about classification of the gas-dynamic discontinuities, shock wave propagation, shock-wave structures and triple configurations of shock waves. We have shown that many of these processes are accompanied by a hysteresis phenomenon, there are areas of ambiguity; therefore, in the design of engines and air intakes optimal shock-wave structures should be provided and their sustainability should be ensured. Much attention has recently been given to the use of the air intakes in the shock-wave structures with the rereflection of shock waves and the interference of shock waves in the opposite directions. This review provides increased focus on it, contains references to landmark works, the last calculated and experimental results. Unfortunately, foreign surveys missed many landmark works of the Soviet and Russian researchers, as they were not published in English. At the same time, it was the Soviet school of gas dynamics that has formulated the interference theory of gas-dynamic discontinuities in its present form. To fill this gap is one of this review scopes. The review may be recommended for professionals, engineers and scientists working in the field of aerospace engineering.
CONCENTRIC LENS SYSTEMS Ezhova Ksenia V, Zverev Victor Alexeevich, Tatiana V. Tochilina
Subject of Research. The paper discusses theoretical foundations of synthesis of concentric lens systems for various applications based on the 3rd order aberration theory. The main difference of concentric lens systems, in addition to the special geometry of the system, is an image spherical surface shape with the radius equal to the focal length of the entire system. For such optical systems compensation is required not only of corner spherical aberration, but also of chromaticity position. Method. The paper presented mathematical apparatus that allows determining the design parameters of the concentric lens systems. The coefficients were introduced determining interrelationship of the radii of curvature for the surfaces of concentric optical systems that gave the possibility to transform the obtained analytical relations in the system of two equations with two unknowns. It is shown that the existence of solutions of the system is determined by the optical constants of the selected lens material. Main Results. The results of correction conditions analysis of the chromatic aberration of position and the sequence of the resulting system of equations have provided theoretical basis for the engineering method of a parametric synthesis of concentric lens systems and developed a mathematical model for the calculation of such systems. Practical Relevance. The undoubted practical significance of the work lies in the examples of specific systems calculation with different possible designs of construction and defining the angular spherical aberration and chromatic aberration of position calculated for each system.
EVALUATION OF CHROMATICITY COORDINATES SHIFT FOR IMAGE DISPLAYED ON LIQUID CRYSTAL PANELS WITH VARIOUS PROPERTIES ON COLOR REPRODUCTION Zharinov Igor Olegovich, Zharinov Oleg O
Subject of Research.We consider the problem of evaluation of chromaticity coordinates shift for image displayed on liquid crystal panels with various properties on color reproduction. A mathematical model represents the color reproduction characteristics. The spread of the color characteristics of the screens has a statistical nature. Differences of color reproduction for screens are perceived by the observer in the form of different colors and shades that are displayed on the same type of commercially available screens. Color differences are characterized by numerical measure of the difference of colors and can be mathematically compensated. The solution of accounting problem of the statistical nature of the color characteristics spread for the screens has a particular relevance to aviation instrumentation. Method. Evaluation of chromaticity coordinates shift of the image is based on the application of the Grassmann laws of color mixing.Basic data for quantitative calculation of shift are the profiles of two different liquid crystal panels defined by matrixes of scales for components of primary colors (red, green, blue). The calculation is based on solving the system of equations and calculating the color difference in the XY-plane. In general, the calculation can be performed in other color spaces: UV, Lab. The statistical nature of the spread of the color characteristics for the screens is accounted for in the proposed mathematical model based on the interval setting of coordinate values of the color gamut triangle vertices on the set of commercially available samples. Main Results. Carried outresearches result in the mathematical expressions allowing to recalculate values of chromaticity coordinates of the image displayed on various samples of liquid crystal screens. It is shown that the spread of the color characteristics of the screens follows bivariate normal distribution law with the accuracy sufficient for practice. The results of simulation are given. We present the ellipses of section for histograms of distribution of chromaticity coordinates for five randomly defined colors that are consistent with the theoretical expressions. Practical Relevance. Research results are usable for engineers designing modern indication equipment based on LCD-panels and for manufacturers while colorimetric calculations and estimation of technological tolerance of chromaticity coordinates among display units in mass production as well.
DESIGNING FEATURES OF POWER OPTICAL UNITS FOR TECHNOLOGICAL EQUIPMENT Afanasiev Maksim Ya , Fedosov Yury V , Nemkova Anastasia A
This paper considers the question of an optical unit designing for transmitting power laser radiation through an optical fiber. The aim of this work is designing a simple construction unit with minimized reflection losses. The source of radiation in the optical unit described below is an ultraviolet laser with diode pumping. We present the general functioning scheme and designing features for the three main parts: laser beam deflecting system, laser beam dump and optical unit control system. The described laser beam deflection system is composed of a moving flat mirror and a spherical scattering mirror. Comparative analysis of the production technology for such mirrors was carried out, and, as a result, the decision was made to produce both mirrors of 99.99 % pure molybdenum without coating. A moving mirror deflects laser emission from a source through a fiber or deflects it on a spherical mirror and into the laser beam dump, moreover, switching from one position to another occurs almost immediately. It is shown that a scattering mirror is necessary, otherwise, the absorbing surface of the beam dump is being worn out irregularly. The laser beam dump is an open conical cavity, in which the conical element with its spire turned to the emission source is placed. Special microgeometry of the internal surface of the beam dump is suggested for the better absorption effect. An optical unit control system consists of a laser beam deflection system, laser temperature sensor, deflection system solenoid temperature sensor, and deflection mirror position sensor. The signal processing algorithm for signals coming from the sensors to the controller is described. The optical unit will be used in special technological equipment.
APPLICATION OF THE LONGITUDINAL CHROMATIC ABERRATION EFFECT FOR DISTANCES MEASUREMENT ON THE BASIS OF A SINGLE PHOTO Volkova Maria A. , Lutsiv Vadim R.
Subject of Research. We propose a method for measuring the distances to the surfaces of photographed objects based on the effect of longitudinal chromatic aberration. According to this effect, the focal length of lens depends on the wavelength of refracted light, thus the defocus of image formed by lens depends not only on the distance from image plane to lens, but also on the wavelength of light the picture was taken for (red, green or blue color ranges). Method. The proposed method of distance measurement is based on comparison of image defocus for different wavelengths (e.g., red and blue). The comparison is performed in the spatial frequency domain and is based on analysis of image complex spectrograms (the Fourier spectrum calculated locally within a window scanning the image).The distance to each point of photographed surface is calculated in closed form by the analysis of local spatial spectrum with the use of Gaussian model of point spread function. Main Results. The working capacity of distance measurement technique is partially verified on the basis of image defocus imitation by different displacement of objective lens with respect to sensor matrix of camera. The presented analysis of chromatic parameters of traditionally applied optical materials also proves the physical realizability of proposed technique. A technology is also proposed for distance measuring based on really differing image defocus in different color channels applying a special calibration of electro-optical system. Practical Relevance. The proposed distance measurement technique could be practically useful in the cases where any active illumination of objects being photographed is prohibited. It is also worth to be applied in the inexpensive low-sized optical measuring devices like Kinect for Xbox-360.
ANALYSIS OF CAMOUFLAGE COVER SPECTRAL CHARACTERISTICS BY IMAGING SPECTROMETER Kouznetsov Alexander Yu., Sergeev Sergey S.
Subject of Research.The paper deals with the problems of detection and identification of objects in hyperspectral imagery. The possibility of object type determination by statistical methods is demonstrated. The possibility of spectral image application for its data type identification is considered. Method. Researching was done by means of videospectral equipment for objects detection at "Fregat" substrate. The postprocessing of hyperspectral information was done with the use of math model of pattern recognition system. The vegetation indexes TCHVI (Three-Channel Vegetation Index) and NDVI (Normalized Difference Vegetation Index) were applied for quality control of object recognition. Neumann-Pearson criterion was offered as a tool for determination of objects differences. Main Results. We have carried out analysis of the spectral characteristics of summer-typecamouflage cover (Germany). We have calculated the density distribution of vegetation indexes. We have obtained statistical characteristics needed for creation of mathematical model for pattern recognition system. We have shown the applicability of vegetation indices for detection of summer camouflage cover on averdure background. We have presented mathematical model of object recognition based on Neumann-Pearson criterion. Practical Relevance. The results may be useful for specialists in the field of hyperspectral data processing for surface state monitoring.
RESEARCH OF THERMO-OPTICAL INHOMOGENEITIES IN Yb-Er GLASS AT DIODE PUMPING Khramov Valery Yu., Chavkin Ivan V. , Chavkina Kseniya M.
Subject of Research. Investigation method of thermo-optical distortions in solid-state lasers was developed and presented. The method can be easily used for research of small diameter (approximately 2 mm) active elements. Method. The experimental method described in this paper is based on the registration of deviation of the energy center of the probe beam passing through the thermally stressed active element. Main Results. We have presented experimental results of the thermal lens optical power research in the active element made of Yb-Er glass pumped transversely by a laser diode in the following modes: without generating, free-running and Q-switching. We have submitted obtained dependences of the optical power on the pumping energy. The measurements have been performed for the two polarization components at two wavelengths (632.8 nm and 1550 nm) showing the absence of explicit astigmatism of the thermal lens. Practical Relevance. Knowledge of the thermal regime of such lasers gives the possibility for more precise calculation of the resonator parameters in terms of the thermal lens occurrence.
OPTICAL PROPERTIES OF CARBAMIDE AQUEOUS SOLUTIONS Avramenko Elena V. , Nikolay P. Belov, Odnovorchenko Pavel V., Sherstobitova Alexandra S., Yaskov Andrey D.
Subject of Research. The paper presents the results of measurements of refractometric properties (refractive index n, its temperature factor dn/dt) and the ultraviolet spectral absorption in carbonic acid diamide aqueous solutions (carbamide) depending on solid residue mass fraction md = 0-50 % and on temperaturet = 10-70 °C.Method of Research. Laboratory methods ofliquid-phase medium refractometry and ultraviolet spectrophotometry were applied for the research. We carried out computational modeling of electronic states spectrum for the carbonic acid diamide molecule and theoretical calculation of the fundamental electronic absorption of the molecule in the ultraviolet wavelenght region.Main Results. We have established that the solution concentration md has a nonlinear character and may be represented by the quadratic polynomial with the error Δn= ± 0,0005. We have shown the refractive indexdependence on temperature n(t) changes in linear fashion att = 10-70 °C.At that, the inclination of lines n(t) increases at the increase of md; so, the temperature factor dn/dt may be approximated by the quadratic polynomial. Transmission spectra of solutions in the spectral region λ= 225-760 nm have no special features except for the sharp edge in the short-wavelength region; the fundamental electronic absorptionis responsible for it. We have established that dispersion dependences of the refraction index n(λ;md) in aqueous solutions of carbamide at λ= 360-760 nm and at md = 0-50 % may be calculated with the satisfactory error without additional adjustable parameters from the ultraviolet absorption data in terms of the one-dimentional oscillator Lorentz model.PracticalRelevance. Representedmeasurements of carbonic acid diamide aqueous solutions optical properties may be applied for the adjustment and calibration of commercial refractometers at processing lines of the AdBlue reagent manufacture for the selective catalytic reduction (SCR) of motor transport exhaust gases.
MATERIAL SCIENCE AND NANOTECHNOLOGIES
FIRE-RESISTANCE PROPERTIES RESEARCH OF “WATER GLASS - GRAPHITE MICROPARTICLES” COMPOSITE MATERIAL Eugene A. Pitukhin , Ustinov Anton S.
Subject of Research. Research results of the fire-resistance for “water glass - graphite microparticles” composite material (CM) are given. The method for fire-resistance test of the micro composition is suggested in order to determine the limit state of the experimental samples under hightemperature action. Method. Test-benchequipment being used for research includes metering devices of temperature and time, as well as laboratory electric furnace PL20 with a maximum temperature in the chamber up to 1250ºC. Fire-resistance limit for the test samples of composite material is determined by the loss of insulating ability (I). For that purpose, the time is obtained from the test beginning with the standard temperature mode up to a limiting condition. Main Results. In accordance with the requirements of regulatory documents fire-resistance limit I15 has been obtained equal to 15 minutes. The qualitative and quantitative phase analysis of the CM structure has been done. By the study of samples by X-ray diffraction and electron microscopy we have determined that the material retains the same chemical structure with a monotonic heating above 700° C. Practical Relevance. The composite material with obtained characteristics can be used as a protective coating for building constructions with the aim of fire-resistance enhancement and fuel hazard reduction.
SEMI-AUTOMATIC SPEAKER VERIFICATION SYSTEM Bulgakova Elena V, Sholokhov Alexey Vladimirovich
Subject of Research. The paper presents a semi-automatic speaker verification system based on comparing of formant values, statistics of phone lengths and melodic characteristics as well. Due to the development of speech technology, there is an increased interest now in searching for expert speaker verification systems, which have high reliability and low labour intensiveness because of the automation of data processing for the expert analysis. System Description. We present a description of a novel system analyzing similarity or distinction of speaker voices based on comparing statistics of phone lengths, formant features and melodic characteristics. The characteristic feature of the proposed system based on fusion of methods is a weak correlation between the analyzed features that leads to a decrease in the error rate of speaker recognition. The system advantage is the possibility to carry out rapid analysis of recordings since the processes of data preprocessing and making decision are automated. We describe the functioning methods as well as fusion of methods to combine their decisions. Main Results. We have tested the system on the speech database of 1190 target trials and 10450 non-target trials, including the Russian speech of the male and female speakers. The recognition accuracy of the system is 98.59% on the database containing records of the male speech, and 96.17% on the database containing records of the female speech. It was also experimentally established that the formant method is the most reliable of all used methods. Practical Significance. Experimental results have shown that proposed system is applicable for the speaker recognition task in the course of phonoscopic examination.
COMPUTATIONALLY EFFICIENT PRIVATE INFORMATION RETRIEVAL PROTOCOL Afanasyeva Alexandra V, Bezzateev Sergey V
This paper describes a new computationally efficient private information retrieval protocol for one q-ary symbol retrieving. The main advantage of the proposed solution lies in a low computational complexity of information extraction procedure, as well as the constructive simplicity and flexibility in choosing the system parameters. Such results are based on cosets properties. The proposed protocol has communication complexity slightly worse than the best schemes at the moment, which is based on locally decodable codes, but it can be easily built for any parameters of the system, as opposed to codes. In comparison with similar solutions based on polynomials, the proposed method gains in computational complexity, which is important especially for servers which must service multiple requests from multiple users.
FORENSIC LINGUISTICS: AUTOMATIC WEB AUTHOR IDENTIFICATION Vorobeva Alisa A.
Internet is anonymous, this allows posting under a false name, on behalf of others or simply anonymous. Thus, individuals, criminal or terrorist organizations can use Internet for criminal purposes; they hide their identity to avoid the prosecuting. Existing approaches and algorithms for author identification of web-posts on Russian language are not effective. The development of proven methods, technics and tools for author identification is extremely important and challenging task. In this work the algorithm and software for authorship identification of web-posts was developed. During the study the effectiveness of several classification and feature selection algorithms were tested. The algorithm includes some important steps: 1) Feature extraction; 2) Features discretization; 3) Feature selection with the most effective Relief-f algorithm (to find the best feature set with the most discriminating power for each set of candidate authors and maximize accuracy of author identification); 4) Author identification on model based on Random Forest algorithm. Random Forest and Relief-f algorithms are used to identify the author of a short text on Russian language for the first time. The important step of author attribution is data preprocessing - discretization of continuous features; earlier it was not applied to improve the efficiency of author identification. The software outputs top q authors with maximum probabilities of authorship. This approach is helpful for manual analysis in forensic linguistics, when developed tool is used to narrow the set of candidate authors. For experiments on 10 candidate authors, real author appeared in to top 3 in 90.02% cases, on first place real author appeared in 70.5% of cases.
DEVELOPMENT AND TESTING OF ERRORS CORRECTION ALGORITHM IN ELECTRONIC DESIGN AUTOMATION Romanova Eva B.
Subject of Research. We have developed and presented a method of design errors correction for printed circuit boards (PCB) in electronic design automation (EDA). Control of process parameters of PCB in EDA is carried out by means of Design Rule Check (DRC) program. The DRC program monitors compliance with the design rules (minimum width of the conductors and gaps, the parameters of pads and via-holes, the parameters of polygons, etc.) and also checks the route tracing, short circuits, the presence of objects outside PCB edge and other design errors. The result of the DRC program running is the generated error report. For quality production of circuit boards DRC-errors should be corrected, that is ensured by the creation of error-free DRC report. Method. A problem of correction repeatability of DRC-errors was identified as a result of trial operation of P-CAD, Altium Designer and KiCAD programs. For its solution the analysis of DRC-errors was carried out; the methods of their correction were studied. DRC-errors were proposed to be clustered. Groups of errors include the types of errors, which correction sequence has no impact on the correction time. The algorithm for correction of DRC-errors is proposed. Main Results. The best correction sequence of DRC-errors has been determined. The algorithm has been tested in the following EDA: P-CAD, Altium Designer and KiCAD. Testing has been carried out on two and four-layer test PCB (digital and analog). Comparison of DRC-errors correction time with the algorithm application to the same time without it has been done. It has been shown that time saved for the DRC-errors correction increases with the number of error types up to 3.7 times. Practical Relevance. The proposed algorithm application will reduce PCB design time and improve the quality of the PCB design. We recommend using the developed algorithm when the number of error types is equal to four or more. The proposed algorithm can be used in different types of modern EDA.
EFFICIENCY OF REDUNDANT QUERY EXECUTION IN MULTI-CHANNEL SERVICE SYSTEMS Bogatyrev Vladimir A, Slastikhin Ivan A.
Subject of Research.The paper deals with analysis of the effectiveness of redundant queries based on untrusted computing in computer systems, represented by multi-channel queuing systems with a common queue. The objective of research is the possibility of increasing the efficiency of service requests while performing redundant copies of requests in different devices of a multi-channel system under conditions of calculations unreliability. The redundant service of requests requires the infallibility of its implementation at least in one of the devices.Method. We have considered estimation of the average time spent in the system with and without the use of redundant requests at the presentation of a simple queuing model of the M / M / n type to analyze the effectiveness of redundant service of requests. Presented evaluation of the average waiting time in the redundant queries is the upper one, since it ignores the possibility of reducing the average waiting time as a result of the spread of the probability of time querying at different devices. The integrated efficiency of redundant service of requests is defined based on the multiplicative index that takes into account the infallibility of calculations and the average time allowance with respect to the maximum tolerated delay of service. Evaluation of error-free computing at reserved queries is received at the requirement of faultless execution of at least one copy of the request. Main Results. We have shown that the reservation of requests gives the gain in efficiency of the system at low demand rate (load). We have defined the boundaries of expediency (efficiency) for redundant service of requests. We have shown the possibility of the effectiveness increasing of the adaptive changes in the multiplicity of the reservation of requests, depending on the intensity of the flow of requests. We have found out that the choice of service discipline in information service systems is largely determined by the economic efficiency of information services, estimated by the profit from the error-free provision of information services obtained per time unit (rate of profit). We have demonstrated the existence of an efficiency area of information services at the redundant service of requests under failures and errors. We have determined the flow rate threshold of requests below which a redundant service of requests is appropriate. Practical Relevance The results presented in the paper can be used in the computer systems design including the systems providing information services.
INVESTIGATION OF NEURAL NETWORK ALGORITHM FOR DETECTION OF NETWORK HOST ANOMALIES IN THE AUTOMATED SEARCH FOR XSS VULNERABILITIES AND SQL INJECTIONS Shabalin Yury D. , Eliseev Vladimir L.
A problem of aberrant behavior detection for network communicating computer is discussed. A novel approach based on dynamic response of computer is introduced. The computer is suggested as a multiple-input multiple-output (MIMO) plant. To characterize dynamic response of the computer on incoming requests a correlation between input data rate and observed output response (outgoing data rate and performance metrics) is used. To distinguish normal and aberrant behavior of the computer one-class neural network classifieris used. General idea of the algorithm is shortly described. Configuration of network testbed for experiments with real attacks and their detection is presented (the automated search for XSS and SQL injections). Real found-XSS and SQL injection attack software was used to model the intrusion scenario. It would be expectable that aberrant behavior of the server will reveal itself by some instantaneous correlation response which will be significantly different from any of normal ones. It is evident that correlation picture of attacks from different malware running, the site homepage overriding on the server (so called defacing), hardware and software failures will differ from correlation picture of normal functioning. Intrusion detection algorithm is investigated to estimate false positive and false negative rates in relation to algorithm parameters. The importance of correlation width value and threshold value selection was emphasized. False positive rate was estimated along the time series of experimental data. Some ideas about enhancement of the algorithm quality and robustness were mentioned.
EVALUATION OF SEMANTIC SIMILARITY FOR SENTENCES IN NATURAL LANGUAGE BY MATHEMATICAL STATISTICS METHODS Pismak Alexey E., Kharitonova Anastassia E., Tsopa Evgeny A, Klimenkov Sergey V.
Subject of Research. The paper is focused on Wiktionary articles structural organization in the aspect of its usage as the base for semantic network. Wiktionary community references, article templates and articles markup features are analyzed. The problem of numerical estimation for semantic similarity of structural elements in Wiktionary articles is considered. Analysis of existing software for semantic similarity estimation of such elements is carried out; algorithms of their functioning are studied; their advantages and disadvantages are shown. Methods. Mathematical statistics methods were used to analyze Wiktionary articles markup features. The method of semantic similarity computing based on statistics data for compared structural elements was proposed.Main Results. We have concluded that there is no possibility for direct use of Wiktionary articles as the source for semantic network. We have proposed to find hidden similarity between article elements, and for that purpose we have developed the algorithm for calculation of confidence coefficients proving that each pair of sentences is semantically near. The research of quantitative and qualitative characteristics for the developed algorithm has shown its major performance advantage over the other existing solutions in the presence of insignificantly higher error rate. Practical Relevance. The resulting algorithm may be useful in developing tools for automatic Wiktionary articles parsing. The developed method could be used in computing of semantic similarity for short text fragments in natural language in case of algorithm performance requirements are higher than its accuracy specifications.
INVESTIGATION OF INFLUENCE OF ENCODING FUNCTION COMPLEXITY ON DISTRIBUTION OF ERROR MASKING PROBABILITY Levina Alla B. , Taranov Sergey V.
Error detection codes are mechanisms that enable robust delivery of data in unreliable communication channels and devices. Unreliable channels and devices are error-prone objects. Respectively, error detection codes allow detecting such errors. There are two classes of error detecting codes - classical codes and security-oriented codes. The classical codes have high percentage of detected errors; however, they have a high probability to miss an error in algebraic manipulation. In order, security-oriented codes are codes with a small Hamming distance and high protection to algebraic manipulation. The probability of error masking is a fundamental parameter of security-oriented codes. A detailed study of this parameter allows analyzing the behavior of the error-correcting code in the case of error injection in the encoding device. In order, the complexity of the encoding function plays an important role in the security-oriented codes. Encoding functions with less computational complexity and a low probability of masking are the best protection of encoding device against malicious acts. This paper investigates the influence of encoding function complexity on the error masking probability distribution. It will be shownthat the more complex encoding function reduces the maximum of error masking probability. It is also shown in the paper that increasing of the function complexity changes the error masking probability distribution. In particular, increasing of computational complexity decreases the difference between the maximum and average value of the error masking probability. Our resultshave shown that functions with greater complexity have smoothed maximums of error masking probability, which significantly complicates the analysis of error-correcting code by attacker. As a result, in case of complex encoding function the probability of the algebraic manipulation is reduced. The paper discusses an approach how to measure the error masking probability in the case of nonuniform distribution of the input code words. This approach can also be used to study the characteristics of security-oriented codes in case of strong and weak models of algebraic manipulation.
ENGINEERING AND TECHNOLOGIES
IMPROVEMENT OF REFERENCE BASE IN THE FIELD OF METROLOGICAL ASSURANCE OF THREAD JOINTS Zakharenko Yury G. , Kononova Natalia A. , Mosckalev Andrey A. , Askarova Elmira F. , Mikheyev Evgeny A.
We consider the main and essential legislative and applicative issues of metrological assurance of thread joints in the Russian Federation and international practice. Basic limitations of the existing measuring methods of the main thread gage parameter - the pitch diameter of thread - are represented. We give the description of the first echelon state working calibration standard for linear unit, placed in service in D.I. Mendeleyev Institute for Metrology (VNIIM), including the general field of applications and metrological characteristics according to the state verification schedule. The possibilities of etalon application in the field of measurements of thread gages parameters are shown. Technical solutions for reducing the components of uncertainty of measurements of the pitch diameter using the etalon are described: temperature stability; reducing of external vibration effects on measuring procedure; developing of the special software for minimizing human factor and increasing automation level of the measuring procedure. The solutions described have enabled to achieve expanded uncertainty value about 0.7-1.0 microns. As a result, we also propose further ways for development and improvement of the system of metrology assurance in the field of thread joints.
MODELING AND SIMULATION
MICROCLIMATE CARTOGRAPHY USING DATA FROM THE EARTH REMOTE SENSING AND SIMULATION OF THERMAL FIELDS Shcherbakov Vladimir M., Altukhov Alexander I., Korshunov Denis S, Voyuts Veronica S.
Subject of Research. The paper proposes geoinformation technology that provides automated compiling of informative microclimatic map by co-processing of digital terrain models, historical dataof meteorological observations and satellite registration of plant vegetation index for a number of years. We present a new solution for urgent task of microclimate cartography according to satellite imagery and modeling of thermal fields. Method. Insolation and vegetation index NDVI were selected as indicators of microclimatic environment areas, showing the main microclimate forming factors that affect the condition of plants and the dynamics of their life cycle phases change. Main Results. We have done the comparison of the seasonal rhythm variability of microclimatic indicators for synchronicity and their being timed to each other. We have defined indicative properties of microclimate parameters, generalization degree of cartographic image, borders for microclimatic cartography. We have presented a fragment of microclimate map obtained with the use of the proposed GIS technology implemented in “ArcGIS” environment. Practical Relevance. Proposed technology allows the creation of formalized microclimate maps showing the distribution of insolation and photosynthetic activity of plants foliage on the Earth surface, taking into account the features of the terrain, and the search for locations favorable for growing the required crops and forecasting solution of problems in the sphere of nature.
NUMERICAL SIMULATION OF SHOCK WAVE DIFFRACTION OVER RIGHT ANGLE ON UNSTRUCTURED MESHES Bulat Pavel V, Volkov Konstantin N.
Subject of Research. Numerical simulation results and investigation of shock wave diffraction of differentintensity on the flat right angleare presented. Method. The numerical model is based on the solution of unsteadyEuler equations for inviscid compressible gas. The finite volume method and explicit WENO-type difference scheme of the third-order of accuracyare used. Convective fluxesare calculated independently for each direction with the approximate Riemann solver(HLLC method). Time integration is performed with the Runge-Kutta method of the third order. Main Results. Flow structure and flowquantitative characteristicshave beendetermined. To visualize and interpret the results of numerical calculations theprocedure of identification and classification of gas-dynamic discontinuities has beenappliedbased on the use of dynamic compatibility conditions and methods of digital image processing. The results of calculations have beenpresented in the form of numerical shadow pictures, schlieren images and interferograms, and compared with the optical observations. Significantly better agreement with the experimental data has beendemonstrated as compared toconventionalnumerical methods. Application of numerical methods of high order accuracy has yielded a numerical solution which is free from non-physicaloscillations on the shock waves with minimal smearingoverdifference cells. Practical Relevance. The study of shock-wave phenomena is of interest for the solution of problems related to the impact of shock waves on the design elements, the operation of pulsed gas-dynamic devices, the use of shock waves in technological processes. Supersonic flows around angle configurations lead to interference and diffraction phenomena complicated by flow separation. These effects make complexthe calculation of such phenomena using conventional numericalmethods. The problem ofthe results interpretation is not less complicated one,as well, in particular, identification of gas-dynamic discontinuities.
MODELING OF RAIL BAR DYNAMIC GAP AT ITS BREAK FOR DIFFERENT STIFFNESS VALUES OF RAIL BASE Zaitseva Tatiana I., Uzdin Alexander M.
Subject of Research.The paper deals with questions of operation safety for continuous welded rail track under dynamic loads. We study the gap value formed in the rail bar in view of its possible break under the conditions of dynamic loads caused by the moving train and varying temperatures. Occurring strains are linked to a variable stiffness of the rail track base (ballast). Methods. We studied longitudinal oscillations in a semi-infinite rod under dynamic loads and in the process of thermal expansion of the finite length rod on the elastic-damped foundation. Oscillatory processes in a semi-infinite rod on an elastic foundation was modeled using the extended equation of longitudinal vibrations, taking into account the reaction of the foundation, performing the role of a damper. To determine the state of the model after the damping of oscillations we used the time limiting transition. In solving the problem of thermal expansion of the finite length rod on the elastic foundation we used equilibrium equation for small fragment, which takes into account the thermal load and the elastic force of both the rod and the foundation. Main Results. We have calculated the maximum value of the dynamic displacement of the rod end at different values of parameters. We have obtained the distributions of stresses and displacements along the rod length for different stiffness distribution in the elastic foundation. In the event of accidental break in the rail, the gap value after the damping of oscillations is set at the level of 5-7 cm. We have shown that the amplitude of these oscillations can reach 10-12 cm. The availability of limited stiffness change zones in the rail base causes no significant deformation of rail bars, but can lead to the growth of the gap in the rail bar break. Practical Relevance. The proposed model can be used in the calculation and design of continuous welded rail tracks.
ALGEBRAIC PROPERTIES OF MATRIX COMPONENTS OF CONTROL PLANT MODELS IN PLACEMENT STATE MATRIX MODES OF SYSTEM ALGORITHMS FOR DESIGNED SYSTEM Vunder Nina A., Ushakov Anatoly Vladimirovich
Subject of Research.The paper deals with the problem of required placement of state matrix modes in the system being designed.Methods.The problem has been solved with the use of vector matrix formalism of state space method with the dominant attention at the algebraic properties of the object control matrix. Main Results. Algebraic conditions have been obtained imposed on the matrix components of control plant and system models, which has helped to create the algorithms for solving the tasks without necessarily resorting to matrix Sylvester equation and Ackermann's formula. Practical Relevance. User’s base of algorithms for synthesis procedures of control systems with specified quality indices has been extended.
ANTIREFLECTION MULTILAYER COATINGS WITH THIN METAL LAYERS Konstantinova Yulia A. , Gubanova Lyudmila Alexandrovna
The design of anti-reflective coatings for metal surfaces of Al, Ti, N,i Cr is proposed. The coatings have the form of alternating layers of dielectric/metal/dielectric with the number of cells up to15. The method of calculation of such coatings is proposed. We have calculated the coatings of the type [HfO2/Cr/HfO2]15, [ZrO2/Ti/Al2O3]15, [ZrO2/Cr/ZrO2]15. It is shown that the proposed interference coatings provide reduction of the residual reflectance of the metal several times (from 3.5 to 6.0) in a wide spectral range (300-1000 nm). The proposed coatings can be recommended as anti-reflective coatings for energy saving solar systems and batteries, and photovoltaic cells.
TWO-STEP ALGORITHM OF TRAINING INITIALIZATION FOR ACOUSTIC MODELS BASED ON DEEP NEURAL NETWORKS Medennikov Ivan P.
This paper presents a two-step initialization algorithm for training of acoustic models based on deep neural networks. The algorithm is focused on reducing the impact of the non-speech segments on the acoustic model training. The idea of the proposed algorithm is to reduce the percentage of non-speech examples in the training set. Effectiveness evaluation of the algorithm has been carried out on the example of English spontaneous telephone speech recognition (Switchboard). The application of the proposed algorithm has led to 3% relative word error rate reduction, compared with the training initialization by restricted Boltzmann machines. The results presented in the paper can be applied in the development of automatic speech recognition systems.
ON THE POSSIBILITY OF BURNING ACCELERATION IN THE COMBUSTION CHAMBERS OF ADVANCED JET ENGINES BY DEEPLY SUBCRITICAL MICROWAVE DISCHARGE Bulat Pavel V, Esakov Igor I. , Volobuev Igor A., Grachev Lev P.
The paper deals with the problem of increasing the speed of propagation of the flame front as applied to the problems of reducing noxious emissions of nitrogen oxides formed during operation of jet engines and industrial turbines, as well as the stabilization of a supersonic combustion. We investigate the possibility of reducing the induction time using non-equilibrium cold plasma produced by an electromagnetic vibrator in beam quasi-optical MW radiation. The positive effect of cold non-equilibrium plasma on increasing the rate of occurrence of oxidation reactions in the air is well known and undisputed. The presented results of the experiments demonstrate the advantage of the method developed in terms of efficiency and suppression of nitrogen oxide emissions. Also they show that combustion stabilization is achieved similarly in a supersonic flow.