Summaries of the Issue
ACCOUNTING OF MANY-PARTICLE INTERACTIONS IN MOLECULAR J-AGGREGATES AND NONLINEAR OPTICAL EFFECTS IN THESE SYSTEMS Nikolay A. Veretenov, Levinsky Boris Nahimovich, Leonid A. Nesterov, Rosanov Nikolay Nikolaevich, Sergey V. Fedorov, Fainberg Boris D.
The paper deals with generalization of investigation materials performed by the authors in recent years and analysis of obtained results. The subject of the paper is accounting of many-particle interactions in molecular J-aggregates at their resonance excitation by laser radiation. In this case, not only twin interactions are taken into considerations, but also the interactions of a given particle with three and more particles simultaneously. Three basic directions can be denoted among carried out investigations. The first direction is connected with derivation (from the first principles) of motion equations for molecular of J-aggregates in view of many-particle interactions, and also twin correlations between particles. The derivation of equations from the first principles leads in general to the system of coupled equations for the means of products of n operators relating to n different molecules. Since n increases in every following equation, the problems arise, connected with uncoupling of this system and also factorization of the means with the highest n. The most difficult and complicated problem in this process is correct calculation of relaxed terms, arising due to exciton-exciton annihilation. The first direction is connected concretely with solution of all above mentioned problems. Within the second direction the study of bistability has been carried out on the basis of obtained equations, in view of three-particle interactions. Meanwhile primary attention has been concentrated on analysis of homogeneous regimes in J-aggregates. It has been shown, in particular, that accounting of many-particle contributions leads to the shift of bistability boundary into region of smaller constants of exciton-exciton annihilation. And, at last, the third direction of investigations is connected with analysis of modulation instability for stationary states of J-aggregates considered earlier at bistability study. The study of stability region boundaries and their correlation with boundaries of bistability regions has been carried out. Obtained results give the possibility to determine more rigorously the parameters region, where nonlinear effects can be observed. They can be used for development of optical logic devices and, in particular, molecular memory circuits.
PHOTONICS AND OPTOINFORMATICS
SERS OF BACTERIORHODOPSIN WITH OUT-DIFFUSED SILVER NANOISLANDS Heisler Fabian , Ekaterina S. Piliugina, Semen D. Chervinskii, Anton K. Samusev, Andrey A. Lipovskii
We present the studies on surface-enhanced Raman spectroscopy (SERS) of bacteriorhodopsin in purple membranes using self-assembled silver nanoisland films for Raman signal enhancement. These metal island films were fabricated on soda-lime glass slides subjected to silver-sodium ion exchange in molten Ag0.05Na0.95NO3 at the temperature of 325°C for 20 minutes and subsequent treatment in hydrogen atmosphere at the temperature of 250°C for 10 minutes. The films typically consisted of 20–30 nm closely placed nanoislands. Being tested as SERS substrates for rhodamine 6G the nanoisland films gave the possibility to observe respective characteristic Raman lines from a dried drop of rhodamine 6G dissolved in water in the concentration of 10–6 M. Similarly fabricated substrates were used to obtain SERS spectra of bacteriorhodopsin in purple membranes dispersed in water, and Raman peaks at 1000–1020 cm–1, 1150–1220 cm–1 and 1530– 1570cm–1 were resolved. The substrates made it possible to register characteristic Raman peaks only for an order of magnitude lower concentration of bacteriorhodopsin in contrast to the virgin glass substrate, that is the enhancement of Raman signal was considerably less than for rhodomin 6G. This is supposed to be due to bacteriophodopsin molecules packing in patches, and it prevents bacteriophodopsin in purple membranes from penetration between the nanoislands where the local enhancement of the electric field of exciting light wave is maximal.
SOLID BODY ABLATION UNDER EXPOSURE TO ULTRA SHORT LASER PULSES: STUDY BY MOLECULAR DYNAMICS METHODS Ivanov Dmitry S, Veiko Vadim Pavlovich, Yakovlev Yevgeniy Borisivich, Carcia Martin E, Rethfeld Baerbel
The process of laser ablation under the influence of ultra short laser pulses on metals is investigated by methods of molecular dynamics. The validity and applicability of the hybrid atomistic-continuous model for the estimation of optimum modes of ultra short laser pulses processing are explored. Combination of atomistic model of laser-induced non-equilibrium process of a phase transition at the atomic level with continuous two-temperature model for describing the dynamics of photo-excitation of free media is proposed. Applicability of laser ablation model on the example of aluminum films and gold under exposure to pulses with different energy density and duration is shown. It is indicated that, depending on the ratio of the laser pulse duration and the characteristic time of electron-phonon material interaction, photothermal and photomechanical modes of destruction are implemented that determine the quality and performance of the laser processing. It is established that at the duration of laser pulse less than the time of electron-phonon interaction high-performance photomechanical type of destruction is implemented by internal stresses arising in the area of exposure. This is confirmed by a linear dependence of the ablation rate from the absorbed energy. At the duration of laser pulse greater than the time of electron-phonon interaction inefficient photothermal mode of destruction is implemented. The results may be useful for specialists engaged in the development of laser technologies
AUTOMATIC CONTROL AND ROBOTICS
FUNDAMENTAL MATRIX OF LINEAR CONTINUOUS SYSTEM IN THE PROBLEM OF ESTIMATING ITS TRANSPORT DELAY Dudarenko Natalya Alexandrovna, Polinova Nina Alexandrovna, Ushakov Anatoly Vladimirovich
The paper deals with the problem of quantitative estimation for transport delay of linear continuous systems. The main result is received by means of fundamental matrix of linear differential equations solutions specified in the normal Cauchy form for the cases of SISO and MIMO systems. Fundamental matrix has the dual property. It means that the weight function of the system can be formed as a free motion of systems. Last one is generated by the vector of initial system conditions, which coincides with the matrix input of the system being researched. Thus, using the properties of the system- solving for fundamental matrix has given the possibility to solve the problem of estimating transport linear continuous system delay without the use of derivation procedure in hardware environment and without formation of exogenous Dirac delta function. The paper is illustrated by examples. The obtained results make it possible to solve the problem of modeling the pure delay links using consecutive chain of aperiodic links of the first order with the equal time constants. Modeling results have proved the correctness of obtained computations. Knowledge of transport delay can be used when configuring multi- component technological complexes and in the diagnosis of their possible functional degeneration.
MATERIAL SCIENCE AND NANOTECHNOLOGIES
THERMAL AND ELECTRIC FIELDS AT SPARK PLASMA SINTERING OF THERMOELECTRIC MATERIALS Lev P. Bulat, Dmitry A. Pshenai-Severin, Irina A. Nefedova, Anna V. Novotelnova, Yuri G. Gurevich
Problem statement. Improvement of thermoelectric figure of merit is connected with the usage of nanostructured thermoelectric materials fabricated from powders by the spark plasma sintering (SPS) method. Preservation of powder nanostructure during sintering is possible at optimum temperature modes of thermoelectrics fabrication. The choice of these modes becomes complicated because of anisotropic properties of semiconductor thermoelectric materials. The decision of the given problem by sintering process simulation demands the competent approach to the problem formulation, a correct specification of thermoelectric properties, the properties of materials forming working installation, and also corrects boundary conditions. The paper deals with the efficient model for sintering of thermoelectrics. Methods. Sintering process of the bismuth telluride thermoelectric material by means of SPS-511S installation is considered. Temperature dependences of electric and thermal conductivities of bismuth telluride, and also temperature dependences of installation elements materials are taken into account. It is shown that temperature distribution in the sample can be defined within the limits of a stationary problem. The simulation is carried out in the software product Comsol Multiphysics. Boundary conditions include convective heat exchange and also radiation under Stefan-Boltzmann law. Results. Computer simulation of electric and thermal processes at spark plasma sintering is carried out. Temperature and electric potential distributions in a sample are obtained at the sintering conditions. Determinative role of graphite compression mould in formation of the temperature field in samples is shown. The influence of geometrical sizes of a graphite compression mould on sintering conditions of nanostructured thermoelectrics is analyzed. Practical importance. The optimum sizes of a cylindrical compression mould for fabrication of volume homogeneous samples based on bismuth telluride are determined. Ways of updating for the sintering process are shown giving the possibility to fabricating thermoelectric samples with predicted properties.
INFLUENCE OF QUARTZ CERAMICS SINGLE-STAGE PROCESSING BY GEL-FORMING WATER SOLUTIONS ON ITS STRENGTH Sergei K. Evstropiev, Valery M. Volynkin, Alexander V. Shashkin, Dukelskiy Konstantin V, Korobeynikov Anatoliy Grigorievich, Gatchin Yuri A, Vladimir I. Polyakov
The main research results of the influence of quartz ceramics processing by silicon- and aluminum-containing gel- forming water solutions on its durability and porosity are given. Aqueous-alcoholic solutions based on tetraethoxysilane (TEOS, Si(C2H5O)4) with additives of aluminum nitrate are proposed for impregnation of porous quartz ceramics samples. Ceramic samples are being impregnated with solutions at the room temperature for 12 minutes. After impregnation they are being exposed to drying at the room temperature for 24 hours and heat treatment in the electric muffle furnace. The made experiments show that impregnation of quartz ceramics porous samples by gel-forming solutions leads to durability growth of not burned samples by 6-7 times even without additional heat treatment. High-temperature heat treatment of previously impregnated ceramic samples leads to decomposition of aluminum nitrate and removal of fossils, and also to hardening of the formed additional bonds between material particles. It considerably improves strength characteristics of quartz ceramics as well. Thus, the possibility of considerable hardening of porous quartz ceramics and stability growth of its strength properties by preliminary impregnation of silicon- and aluminum-bearing gel-forming solutions even without additional heat treatment is experimentally shown. It is revealed that impregnation of porous quartz ceramic samples by these solutions leads only to insignificant reduction of porosity of samples. Subsequent heat treatment of the impregnated porous ceramic samples at the temperatures, equal to 900-1200oC, results in additional significant increase in their mechanical durability.
INVESTIGATION OF SORPTION CHARACTERISTICS OF POLYMERIC MINERAL-FILLED COMPOSITES FOR MEDICINE Yuliya A. Ignatieva, Uspenskaya Maya Valerievna, Oleg V. Borisov, Olekhnovich Roman O, Roman A. Evseev, Kirill N. Kasanov
The polymer compositions on the base of acrylic derivatives and bentonite particles modified by silver ions with various share and dispersion are received and studied by radical polymerization in the water. Partially neutralized acrylic acid, acrylamide and methylene-bis-acrilamide and particles of bentonite with fraction 0 - 0,05 mass.% are chosen as initial substances. The influence of bentonite concentration on absorbing characteristics of polymer materials in the distilled water is shown. It is demonstrated that the increase of bentonite fraction up to 5 mass.% leads to the rise of degree of equilibrium swelling by 1,5 – 2 times in comparison with an unfilled polymer matrix. The acrylic nanocompositions with a mass fraction of bentonite equal to 0,01 mass.% possess the greatest kinetic characteristics. Kinetic dependences of new composite materials swelling in physiological solution from a filler dispersion part are investigated. It is shown that in high dispersion (with particle size less than 0,25 mm) a part of mineral–containing filler equal to 1 mass.% leads to significant increase in values of equilibrium swelling degree in comparison with an unfilled sample (by 1,5 times). The effect of polyelectrolyte suppression of polymer composition swelling in physiological solution is studied. It results in values reduction of equilibrium swelling degree in comparison with these values in the distilled water. Application prospects for the received compositions are shown at bandages creation for wounds treatment of various etiologies. Research results are recommended for usage in medical practice for optimization of wound process march.
CRYSTALLIZATION KINETICS OF POLYMERIC NANOCOMPOSITES BASED ON POLYAMIDE 12 MODIFIED BY Cr2O3 NANOPARTICLES Shapoval Ekaterina Sergeevna, Zuev Vyacheslav Viktorovich
In situ polymerization method is used for obtaining polymeric composites based on polyamide12 matrix (PA 12), filled with Cr2O3 nanoparticles. The carried out researches result in synthesis method development for polymeric nanocomposites based on PA 12 matrix filled with nano-sized Cr2O3magnetic particles providing uniform embedding of the filler into polymeric matrix without formation of nanoparticles agglomerates. Mechanical tests on samples compression are carried out. It is shown that mechanical properties of polymeric composites (Young’s modulus, durability limit) are decreased for 20-30 % as compared with not modified PA 12 synthesized by means of the chosen method. The influence of the filler on crystallization morphology and kinetics of polymeric nanocomposites is determined by electron microscopy and differential scanning calorimetry. The values of crystallization degree, crystallization rate constant for different supercooling intervals and parameters of Avrami equation are obtained. The initial nucleation is shown to be going on according to non-thermal mechanism, and nanoparticles are not the germs of crystallization. It is stated that nanoparticles are embedded into polymeric matrix and uniformly allocated in crystallites. Research results can find their application at creation of electric and magnetic fields, micro-sized mechanical devices, and at development of new materials for 3D printers.
INORGANIC PHOSPHORS IN GLASS BASED ON LEAD SILICATE GLASSES Vladimir A. Aseev, Anastasiya Yu. Bibik, Kolobkova Elena V, Nekrasova Yana Andreevna, Nikonorov Nikolay V. , Romanov Alexey E, Julia V. Tuzova, Mariya A. Shvaleva
We created and synthesized luminescent composite of the "phosphor in glass" type, based on the lead-silicate matrix and fine-dispersed powder of cerium-activated yttrium-aluminum garnet crystal. Lead-silicate system (40SiO2-20PbO-(40-x) PbF2-xAlF3, x = 0-25) was chosen as the glassy matrix. Initial glass was reduced to powder (frit) for "phosphor in glass" composite with a particle size about 50 µm. Glass frit and powder of commercial YAG:Ce3+ phosphor were mixed in a ratio of 30 to 70 (wt %). Then this composite was pressed in a tablet and sintered on a quartz substrate at 823 К for 30 minutes. Thus, the plane parallel sheet for composite of the "phosphor in glass" was obtained with a diameter equal to 10 mm. For the purpose to reduce the loss of light in the presence of dispersion at a glass-phosphor boundary, optimization of glass mixture was done by adjusting the refractive index. X-ray phase and spectral-luminescent analysis of the derived composite were done. The results of these studies showed that there was no degradation of YAG: Ce powder during sintering. Dependence of luminescence intensity from temperature in the range from room temperature to 473 К was studied. It was shown, that with the phosphor in glass usage thermal quenching of luminescence was reduced in comparison with the silicone. The model of white LED was created with the "phosphor in glass" composite based on lead-silicate glasses with low temperature of vitrifying. The derived LED emits white light with a color temperature of 4370 K, and the luminous efficiency is equal to 58 lm/W. The developed luminescent composite based on the lead-silicate matrix can be used for the production of high-power white light LED.
IMPROVEMENT OF RECOGNITION QUALITY IN DEEP LEARNING NETWORKS BY SIMULATED ANNEALING METHOD Potapov Alexey Sergeevich, Vita V. Batishcheva, Shu-Chao Pang
The subject of this research is deep learning methods, in which automatic construction of feature transforms is taken place in tasks of pattern recognition. Multilayer autoencoders have been taken as the considered type of deep learning networks. Autoencoders perform nonlinear feature transform with logistic regression as an upper classification layer. In order to verify the hypothesis of possibility to improve recognition rate by global optimization of parameters for deep learning networks, which are traditionally trained layer-by-layer by gradient descent, a new method has been designed and implemented. The method applies simulated annealing for tuning connection weights of autoencoders while regression layer is simultaneously trained by stochastic gradient descent. Experiments held by means of standard MNIST handwritten digit database have shown the decrease of recognition error rate from 1.1 to 1.5 times in case of the modified method comparing to the traditional method, which is based on local optimization. Thus, overfitting effect doesn’t appear and the possibility to improve learning rate is confirmed in deep learning networks by global optimization methods (in terms of increasing recognition probability). Research results can be applied for improving the probability of pattern recognition in the fields, which require automatic construction of nonlinear feature transforms, in particular, in the image recognition. Keywords: pattern recognition, deep learning, autoencoder, logistic regression, simulated annealing.
EXPERIMENTAL STUDY OF FIRMWARE FOR INPUT AND EXTRACTION OF USER’S VOICE SIGNAL IN VOICE AUTHENTICATION SYSTEMS Olha N. Faizulaieva, Igor S. Nevlyudov
T Scientific task for improving the signal-to-noise ratio for user’s voice signal in computer systems and networks during the process of user’s voice authentication is considered. The object of study is the process of input and extraction of the voice signal of authentication system user in computer systems and networks. Methods and means for input and extraction of the voice signal on the background of external interference signals are investigated. Ways for quality improving of the user’s voice signal in systems of voice authentication are investigated experimentally. Firmware means for experimental unit of input and extraction of the user’s voice signal against external interference influence are considered. As modern computer means, including mobile, have two-channel audio card, two microphones are used in the voice signal input. The distance between sonic-wave sensors is 20 mm and it provides forming one direction pattern lobe of microphone array in a desired area of voice signal registration (from 100 Hz to 8 kHz). According to the results of experimental studies, the usage of directional properties of the proposed microphone array and space-time processing of the recorded signals with implementation of constant and adaptive weighting factors has made it possible to reduce considerably the influence of interference signals. The results of firmware experimental studies for input and extraction of the user’s voice signal against external interference influence are shown. The proposed solutions will give the possibility to improve the value of the signal/noise ratio of the useful signals recorded up to 20 dB under the influence of external interference signals in the frequency range from 4 to 8 kHz. The results may be useful to specialists working in the field of voice recognition and speaker discrimination.
SYSTEMS FOR SUPPORT OF COLLABORATIVE STUDIES IN THE COLLA ENVIRONMENT BASED ON THE EVENT BUSH METHOD Diviacco Paolo , Cyril A. Pshenichny, Behncke Boris , Oksana M. Kanzheleva
Problem statement. Conventional tools of online communication in global networks for support of scientific and research projects fail to handle specific issues that arise at scientific collaboration of different scientific schools. They cannot be used to bring together the knowledge relating to the same field but generated in various scientific schools, under different paradigms and on different conceptual grounds. Existing software solutions, both synchronous (e.g., Webex or ShowDocument) and asynchronous (Zimbra, Google Docs and others) are efficient only when the users share similar understanding of the context and do not bring their own non-formalized meanings in it. Meanwhile, a tool is needed for scientific cooperation that makes it possible to bring one’s own meanings and relate them to the common context. Methods. Special tools for support of collaborative research in the COLLA environment using the methods of knowledge engineering and knowledge representation are given. Effective modeling of many knowledge domains is shown to require special methods of dynamic knowledge modeling; one of the well-developed is the event bush method. Results. The paper deals with issues of combination of the event bush method and COLLA collaborative research support technique on the example of S&R projects in seismology and volcanology. Approach approbation is done on the example of two urgent tasks for geosciences: estimation of progress scenarios for geological disasters caused by Etna eruption, one of the most dangerous European volcanoes, and one of the most perilous earthquake effects (location effect). Practical application. Event bush method can be used for quantitative assessment of similarity-difference for modeled effects based on the expert knowledge about them. This opportunity can find its substance in many fields of science far beyond geosciences.
BILINGUAL MULTIMODAL SYSTEM FOR TEXT-TO-AUDIOVISUAL SPEECH AND SIGN LANGUAGE SYNTHESIS Karpov Alexey A, Zelezny Milos
We present a conceptual model, architecture and software of a multimodal system for audio-visual speech and sign language synthesis by the input text. The main components of the developed multimodal synthesis system (signing avatar) are: automatic text processor for input text analysis; simulation 3D model of human's head; computer text-to-speech synthesizer; a system for audio-visual speech synthesis; simulation 3D model of human’s hands and upper body; multimodal user interface integrating all the components for generation of audio, visual and signed speech. The proposed system performs automatic translation of input textual information into speech (audio information) and gestures (video information), information fusion and its output in the form of multimedia information. A user can input any grammatically correct text in Russian or Czech languages to the system; it is analyzed by the text processor to detect sentences, words and characters. Then this textual information is converted into symbols of the sign language notation. We apply international «Hamburg Notation System» - HamNoSys, which describes the main differential features of each manual sign: hand shape, hand orientation, place and type of movement. On their basis the 3D signing avatar displays the elements of the sign language. The virtual 3D model of human’s head and upper body has been created using VRML virtual reality modeling language, and it is controlled by the software based on OpenGL graphical library. The developed multimodal synthesis system is a universal one since it is oriented for both regular users and disabled people (in particular, for the hard-of-hearing and visually impaired), and it serves for multimedia output (by audio and visual modalities) of input textual information.
POLICE OFFICE MODEL IMPROVEMENT FOR SECURITY OF SWARM ROBOTIC SYSTEMS Igor A. Zikratov, Andrei V. Gurtov, Zikratova Tatyana Viktorovna, Kozlova Ekaterina Vadimirovna
This paper focuses on aspects of information security for group of mobile robotic systems with swarm intellect. The ways for hidden attacks realization by the opposing party on swarm algorithm are discussed. We have fulfilled numerical modeling of potentially destructive information influence on the ant shortest path algorithm. We have demonstrated the consequences of attacks on the ant algorithm with different concentration in a swarm of subversive robots. Approaches are suggested for information security mechanisms in swarm robotic systems, based on the principles of centralized security management for mobile agents. We have developed the method of forming a self-organizing information security management system for robotic agents in swarm groups implementing POM (Police Office Model – a security model based on police offices), to provide information security in multi-agent systems. The method is based on the usage of police station network in the graph nodes, which have functions of identification and authentication of agents, identifying subversive robots by both their formal characteristics and their behavior in the swarm. We have suggested a list of software and hardware components for police stations, consisting of: communication channels between the robots in police office, nodes register, a database of robotic agents, a database of encryption and decryption module. We have suggested the variants of logic for the mechanism of information security in swarm systems with different temporary diagrams of data communication between police stations. We present comparative analysis of implementation of protected swarm systems depending on the functioning logic of police offices, integrated in swarm system. It is shown that the security model saves the ability to operate in noisy environments, when the duration of the interference is comparable to the time necessary for the agent to overcome the path between police stations.
RELATIONAL THEORY APPLICATION FOR OPTIMAL DESIGN OF INTEGRATED CIRCUITS Demidov Daniil Valentinovich
This paper deals with a method of relational theory adaptation for integrated circuits CAD systems. A new algorithm is worked out for optimal search of implicit Don’t Care values for combinational multiple-level digital circuits. The algorithm is described in terms of the adapted relational theory that gives the possibility for a very simple algorithm description for both intuitive understanding and formal analysis. The proposed method makes it possible to apply progressive experience of relational databases in efficient implementation of relational algebra operations (including distributed ones). Comparative analysis of the proposed algorithm and a classic one for optimal search of implicit Don’t Cares is carried out. The analysis has proved formal correctness of the proposed algorithm and its considerably less worst-case complexity. The search of implicit Don’t Care values in the integrated circuits design makes it easier to optimize such characteristics of IC as chip area, power, verifiability and reliability. However, the classic algorithm for optimal search of implicit Don’t Care values is not used in practice due to its very high computational complexity. Application of algorithms for sub-optimal search doesn’t give the possibility to realize the potential of IC optimization to the full. Implementation of the proposed algorithm in IC CAD (a.k.a., EDA) systems is adequate due to much lower computational complexity, and potentially makes it possible to improve the quality-development time ratio of IC (chip area, power, verifiability and reliability). Developed method gives the possibility for creation of distributed EDA system with higher computational power and, consequently, for design automation of more complex IC.
INTERVALS OPTIMIZATION OF SYSTEMS INFORMATION SECURITY INSPECTION Bogatyrev Vladimir A, Bogatyrev Anatoly Vladimirovich, Bogatyryev Stanislav Vladimirovich
A Markov model is suggested for secure information systems, functioning under conditions of destructive impacts, which aftereffects are found by on-line and test control. It is assumed that on-line control, in contrast to the test one, is char- acterized by the limited control completeness, but does not require the stopping of computational process. The aim of re- search is to create models that optimize intervals of test control initialization by the criterion of probability maximization for system stay in the ready state to secure fulfillment of the functional requests and minimization of the dangerous system states in view of the uncertainty and intensity variance of the destructive impacts. Variants of testing intervals optimization are con- sidered depending on the intensity of destructive impacts by the criterion of the maximum system availability for the safe execution of queries. Optimization is carried out with and without adaptation to the actual intensity change of destructive impacts. The efficiency of adaptive change for testing periods is shown depending on the observed activity of destructive impacts. The solution of optimization problem is obtained by built-in tools of computer mathematics Mathcad 15, including symbolic mathematics for solution of systems of algebraic equations. The proposed models and methods of determining the optimal testing intervals can find their application in the system design of computer systems and networks of critical applications, working under conditions of destabilizing actions with the increased requirements for their safety.
ALGORITHM FOR SEMANTIC TEXT ANALYSIS BY MEANS OF BASIC SEMANTIC TEMPLATES WITH DELETION Anastasia V. Mochalova
The systems of automatic text processing have become more and more important due to the constant growth of textual data. One of the main issues arising in such systems is a problem of semantic analysis. The paper deals with an algorithm for finding semantic dependencies by means of basic semantic templates with deletion. While working with the Drools expert system (and PHREAK algorithm for fast pattern matching) we have developed and implemented a semantic analyzer for construction of semantic dependencies between parts of a sentence. During the semantic analysis we add some text parts to the priority queue according to the rules described in the semantic templates, and then at each iteration of the sentence being analyzed we drop some segment of the analyzed text which has the highest priority in the queue. To determine the priority in this queue two values are used: the priority of semantic relationship group and word position. The proposed algorithm is implemented in Java. We have prepared 2160 rules using Drools expert system. The software implementation of the proposed algorithm has shown its applicability for the systems of automatic text processing. Testing results have proved that suggested algorithm of semantic analysis without Drools expert system operates 6-8 times slower, on the average. We use proposed semantic analyzer as a composite module to intellectual question-answering system.
ARCHITECTURE OF WEB BASED COMPUTER-AIDED MANUFACTURING SYSTEM Nikolay E. Filyukov
The paper deals with design of a web-based system for Computer-Aided Manufacturing (CAM). Remote applications and databases located in the "private cloud" are proposed to be the basis of such system. The suggested approach contains: service - oriented architecture, using web applications and web services as modules, multi-agent technologies for implementation of information exchange functions between the components of the system and the usage of PDM - system for managing technology projects within the CAM. The proposed architecture involves CAM conversion into the corporate information system that will provide coordinated functioning of subsystems based on a common information space, as well as parallelize collective work on technology projects and be able to provide effective control of production planning. A system has been developed within this architecture which gives the possibility for a rather simple technological subsystems connect to the system and implementation of their interaction. The system makes it possible to produce CAM configuration for a particular company on the set of developed subsystems and databases specifying appropriate access rights for employees of the company. The proposed approach simplifies maintenance of software and information support for CAM subsystems due to their central location in the data center. The results can be used as a basis for CAM design and testing within the learning process for development and modernization of the system algorithms, and then can be tested in the extended enterprise.
MODELING AND SIMULATION
SIMULATION OF PULSED BREAKDOWN IN HELIUM BY ADAPTIVE METHODS Stepan I Eliseev, Vladimir I. Demidov, Chirtsov Alexander S, Anatoly A. Kudryavtsev, Kolobov Vladimir I, Evgeny A. Bogdanov
The paper deals with the processes occurring during electrical breakdown in gases as well as numerical simulation of these processes using adaptive mesh refinement methods. Discharge between needle electrodes in helium at atmospheric pressure is selected for the test simulation. Physical model of the accompanying breakdown processes is based on self- consistent system of continuity equations for streams of charged particles (electrons and positive ions) and Poisson equation for electric potential. Sharp plasma heterogeneity in the area of streamers requires the usage of adaptive algorithms for constructing of computational grids for modeling. The method for grid adaptive construction together with justification of its effectiveness for significantly unsteady gas breakdown simulation at atmospheric pressure is described. Upgraded version of Gerris package is used for numerical simulation of electrical gas breakdown. Software package, originally focused on solution of nonlinear problems in fluid dynamics, appears to be suitable for processes modeling in non-stationary plasma described by continuity equations. The usage of adaptive grids makes it possible to get an adequate numerical model for the breakdown development in the system of needle electrodes. Breakdown dynamics is illustrated by contour plots of electron densities and electric field intensity obtained in the course of solving. Breakdown mechanism of positive and negative (orientated to anode) streamers formation is demonstrated and analyzed. Correspondence between adaptive building of computational grid and generated plasma gradients is shown. Obtained results can be used as a basis for full-scale numerical experiments on electric breakdown in gases.
ON ALGORITHMS CREATION FOR STRAPDOWN STABILIZED GYROCOMPASS OPERATION BASED ON ELECTRICALLY SUSPENDED GYROSCOPE Emelyantsev Gennady Ivanivich, Andrei A. Medvedkov, Tijing Cai
The paper presents operation algorithms of ESG-based strapdown stabilized gyrocompass (SSGC) located onboard a mobile vehicle. Initial alignment mode and calibration of drift model coefficients onboard a vehicle is aided by reference attitude (heading, pitch and roll angles) and position data. The required reference attitude parameters can be generated by joint processing of data from MEMS IMU with gyros and accelerometers and GPS compass. Depending on the vehicle dynamics and required accuracy of generated heading, the system may use IMU based on the fiber-optic gyros and accelerometers instead of MEMS to construct the place vertical. Specific features of SSGC algorithms in heading generation are considered. Calibration and corrected operation modes of the system are described. The SSGC uses two ESGs with orthogonal angular momentum vectors, where one gyro is the reference (unit vector of its angular momentum is aligned with the celestial axis) and the other one is virtual (with zero misalignments with respect to the inertial frame, and zero drift model coefficients). Joint processing of SSGC data and external position aiding is realized by extended Kalman filter with full-state feedback control. Simulation modeling results of the system operation algorithms are presented. Simulation modeling has confirmed the system compass effect and determined the time required for calibration of ESG with solid-rotor. The results have been applied at «Concern CSRI “Elektropribor”», JSC.
MODELING AND EXPERIMENTAL STUDY OF A FIBER OPTIC HYDROPHONE SENSING ELEMENT Plotnikov Mikhail Yurievich, Kulikov Andrey Vladimirovich, Efimov Mikhail E
A model of the fiber-optic hydrophone sensor is suggested. Hydrophone construction comprises a malleable core made of a polymeric material with regulated elastic properties to which the optical fiber is wound. The built-in module of Comsol Multiphysics - Acoustic Solid Interaction is used in the simulation; it evaluates the impact of the acoustic field of different frequencies and amplitudes on the value of the sensor surface deformation. The proposed model gives the possibility for simulating the hydrophone in various environments; materials and dimensions of sensor are selected at the design stage to ensure the required performance: frequency response and sensitivity of fiber optic hydrophone. Correctness of the model construction was verified by results comparison of the computer simulation and experimental study in the acoustic pool. The prototype was represented as the phase interferometric fiber-optic hydrophone on the Bragg gratings. The sensing element is formed as a cylindrical core round which the optical fiber is wound. Core characteristics are: the material attenuation (damping) – 0.1, Young's modulus of the core - 6 MPa, Poisson’s ratio - 0.49. The prototype was tested in the experimental pool, which design makes it possible to carry out measurements at frequencies above 3 kHz in the absence of reflections of the acoustic signal. The impact assessment of the acoustic field is carried out by means of an approved piezoelectric hydrophone: the amplitude of the acoustic field of a plane wave is 0.5 and 1 Pa, frequencies of the acoustic impact are 3000 - 8000 Hz. According to the findings fabricated prototype sensitivity was equal to 0.1 rad / Pa at the frequency of 3 kHz. Studies have shown that the sensitivity of the simulated fiber optic hydrophone will decrease with increasing frequency of hydroacoustic exposure. At 8 kHz frequency the sensitivity is decreased to 0.01 rad / Pa. Prototype testing results have confirmed the adequacy of the computer model that makes it possible to recommend the proposed model for the development and study of fiber optic hydrophones
INFORMATION TECHNOLOGIES IN EDUCATION
NEW APPROACHES TO EFFICIENCY OF MASSIVE ONLINE COURSE Liubov S. Lysitsina, Pershin Alexander Alexandrovich, Vladimir L. Uskov
This paper is focused on efficiency of e-learning, in general, and massive online course in programming and information technology, in particular. Several innovative approaches and scenarios have been proposed, developed, implemented and verified by the authors, including 1) a new approach to organize and use automatic immediate feedback that significantly helps a learner to verify developed code and increases an efficiency of learning, 2) a new approach to construct learning interfaces – it is based on “develop a code – get a result – validate a code” technique, 3) three scenarios of visualization and verification of developed code, 4) a new multi-stage approach to solve complex programming assignments, 5) a new implementation of “perfectionism” game mechanics in a massive online course. Overall, due to implementation of proposed and developed approaches, the efficiency of massive online course has been considerably increased, particularly 1) the additional 27.9 % of students were able to complete successfully “Web design and development using HTML5 and CSS3” massive online course at ITMO University, and 2) based on feedback from 5588 students a “perfectionism” game mechanics noticeably improves students’ involvement into course activities and retention factor.
INFORMATION INFRASTRUCTURE OF THE EDUCATIONAL ENVIRONMENT WITH VIRTUAL MACHINE TECHNOLOGY Gusarova Natalya Fedorovna, Ivanov Roman Vladimirovich, Artem D. Beresnev, Dmitry N. Fedotov
Subject of research. Information infrastructure for the training environment with application of technology of virtual computers for small pedagogical systems (separate classes, author's courses) is created and investigated. Research technique. The life cycle model of information infrastructure for small pedagogical systems with usage of virtual computers in ARIS methodology is constructed. The technique of information infrastructure formation with virtual computers on the basis of process approach is offered. The model of an event chain in combination with the environment chart is used as the basic model. For each function of the event chain the necessary set of means of information and program support is defined. Technique application is illustrated on the example of information infrastructure design for the educational environment taking into account specific character of small pedagogical systems. Advantages of the designed information infrastructure are: the maximum usage of open or free components; the usage of standard protocols (mainly, HTTP and HTTPS); the maximum portability (application servers can be started up on any of widespread operating systems); uniform interface to management of various virtualization platforms, possibility of inventory of contents of the virtual computer without its start, flexible inventory management of the virtual computer by means of adjusted chains of rules. Approbation. Approbation of obtained results was carried out on the basis of training center "Institute of Informatics and Computer Facilities" (Tallinn, Estonia). Technique application within the course "Computer and Software Usage" gave the possibility to get half as much the number of refusals for components of the information infrastructure demanding intervention of the technical specialist, and also the time for elimination of such malfunctions. Besides, the pupils who have got broader experience with computer and software, showed better results within tests due to the usage of information infrastructure with virtual computers. Practical application. Obtained output can be recommended for introduction into the activity of educational institutions of secondary and higher education, and also for developing the author's and specialized courses focused on collective actions of pupils.
TWO-LAYER PHASE COMPENSATING INTERFERENCE SYSTEMS Georgiy V. Nikandrov, Putilin Edvard Stepanovich, Gubanova Lyudmila Alexandrovna, Starodubov Dmitry Sergeeivich
The paper deals with creation of optical interferential coatings, giving the possibility to form the wave front without the change of energy characteristics of the incident and reflected radiation. Correction is achieved due to the layer, which thickness is a function of coordinate of an optical element surface. Selection technique is suggested for refractive index materials, forming two-layer interference coating that creates a coating with a constant coefficient of reflection on the surface of the optical element. By this procedure the change of coefficient of reflection for the optical element surface, arising because of the variable thickness is eliminated. Magnesium oxide and zirconium dioxide were used as the film-forming materials. The paper presents experimentally obtained thickness distribution of the layer, which is a part of the phase compensating coating. A new class of optical coatings proposed in the paper can find its application for correcting the form of a wave front.
A PROTOTYPE OF BARENTSNET PROFESSIONAL SOCIAL NETWORK FOR INFORMATION SUPPORT OF DEVELOPMENT MANAGEMENT FOR BARENTS EURO-ARCTIC REGION Masloboev Andrey V, Strand Remi Morten
A prototype of professional social network BarentsNet has been developed for management activities information support of entities participating in the management process of developing and resource potential settling of the Barents Euro- Arctic region. BarentsNet system is implemented as a multi-domain web-service and provides formalized ontology-based expert knowledge integration of the Arctic and sub-Arctic territories development features, and professional contacts linking automation within the system for cooperation and joint project realization in this sphere. The functionality organization model, executive core and software components of the BarentsNet system have been developed.