Статьи журнала - Сибирский аэрокосмический журнал
Все статьи: 3183
Статья научная
The problem of vector-based semantic classification over the words and notions of the natural language is discussed. A set of generative grammar rules is offered for generating the semantic classification vector. Examples of the classification application and a theorem of optional formal classification incompleteness are presented. The principles of assigning the meaningful phrases functions over the classification word groups are analyzed.
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Emotion recognition and speaker identification from speech
Статья
The performance of spoken dialogue systems (SDS) is not perfect yet, especially for some languages. Emotion recognition from speech (ER) is a technique which can improve the SDS behavior by finding critical points in the human-machine interaction and changing a dialogue strategy. Inclusion of the speaker specific information, by conducting the speaker identification procedure (SI) at the set up of ER task could also be used in order to improve the dialogue quality. Choosing of both appropriate speech signal features and machine learning algorithms for the ER and SI remain a complex and challenging problem. More than 50 machine learning algorithms were applied in the study for ER and SI tasks, using 9 multi-language corpora (Russian, English, German, and Japanese) of both acted and non-acted emotional utterance recordings. The study provides the results of evaluation as well as their analysis and future directions.
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Empirical relationship for queue length estimation in a system with fractal shot input
Статья научная
Traffic in modern data networks and information systems are most adequately described by different classes of fractal models. This kind of models takes into account the following key characteristics of traffic as high variability events grouping and explicit correlation structure on different time scales. Fractal shot process FSNDP, referring to the fractal point process is sufficiently accurate approximation of the network load at individual workstations or small workgroups, is defined with five numerical parameters, with known estimating algorithms on available samples (based on actual traffic dumps). Studies based on queueing system simulation with input FSNDP stream managed to establish a stable relationship between the change in each of the input parameters and the average queue length in the system. Confirmed direct correlation queue length of the parameter characterizing the amplitude of the individual load bursts, found an inverse relationship of the index related to the Hurst parameter and master degree of fractal properties. Based on the identified dependencies, obtained empirical relations between parameters of FSNDP process and the average queue length in single-channel queueing system with unlimited queue and deterministic service discipline FSNDP/D/1. These relationships allow to estimate the average volume of buffer used and the average delay introduced by the network equipment in the load conditions expressed fractal properties from measurements of real traffic. The presence of the formulae increases the importance of traffic models based on FSNPD, since it makes possible to perform a full cycle analysis of queueing systems and queueing networks without involving the simulation methods.
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Статья научная
In this article the integrated approach for automatic formation ensembles of neural networks is proposed. The applying multi-criteria “Self-configurable” genetic programming is described. To each new generated network the mostefficient (“best”) network is added, which by two criteria were estimated on the first stage of the algorithm. Thusa population of neuralnetwork ensembles is created. The criterion of effectiveness of new networks is the third criterion –the effectiveness of ensemble decision, which includes in this network ensemble. Thefinal ensemble with selected net-works by third criteria is created. Also in this article the approach forformation of ensemble decision using the decisions of an added neural networks – Scheme ED1 is applied. Proposed method ondifferent tasks with different amountof inputs and outputs signals (neurons) in ANN was tested. In the resultthis method shows high efficiency.
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Статья научная
In this paper we present an approach which allows us to avoid expansive and time consuming subjective assessments of audio quality degradation caused by different nature distortions while transmitting and receiving of stereo audio signal through the radio channel. This approach is based on the basic version of PEAQ (Perceptual Evaluation of Audio Quality) originally developed mainly for audio codec estimation. The MOV (Model Output Variables) vector of the PEAQ method is mapped to the audio quality degradation scale using two different models: neural networks and non-parametric regression. The results of two independent approaches are compared.
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Статья научная
A lot of sets of subjects and objects in biology, industry, management can be divided into a number of classes, each of which corresponds to a certain distribution component. When analyzing a mixture of distributions, it is necessary to estimate its parameters (task 1) and to assess the correspondence of empirical and theoretical distribution functions (task 2). To solve the first problem, numerical algorithms that implement the method of moments and the maximum likelihood method are used. In this paper, the problem of estimating the distribution parameters is solved by minimizing the good- ness measure by the Quasi-Newton method. The second problem is solved by comparing the empirical and theoretical distribution functions by one or several statistical goodness measures. Statistics of the distribution of these measures depends on the sample size, the method of forming data and estimating distribution parameters. The paper examines the goodness measure between Frocini and omega-square (Kramer - Mises - Smirnov). The evaluation of the statistics of the goodness measure was carried out by the simulation method based on the results of 50000 statistical tests. In each of the tests, the distribution parameters were estimated by minimizing the calculated value of the corresponding goodness measure. The results of simulation modeling allow estimating the statistics of the parameters of a mixture of distributions. The results of solving the considered problems for a mixture of two normal distributions of size 240 are pre- sented.
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Статья научная
Transport operations that ensure the change of the orbit of a spacecraft or its transfer to the departure trajectory are an integral part of almost all space missions. Increasing requirements for the efficiency of transporting spacecraft form the need to search for possible ways to increase this efficiency and assess the characteristics associated with the proposed methods. Current boosters and interorbital tugs, as a rule, use a chemically powered cruise engine, although solutions with the use of an electric jet engine are becoming more common. Due to the high rate of the outflow of working fluid which is much higher than that of combustion products in a chemical engine, the efficiency of use of the substance mass by an electric jet engine significantly exceeds this indicator for a chemical engine. However, the low thrust provided by the electric jet engine leads to high duration of the transport operation and, as a result, to considerable time of exposure to the outer space factors, in particular, radiation. Therefore, the use of the electric jet engine only does not always meet the requirements for the mission. One of the promising ways to increase the efficiency of transport operations is the combination of the traditional chemical and electric jet engines in the propulsion system. Various aspects of the use of such an integrated propulsion system (IPS) consisting of a solar electric jet system and “Fregat” booster were considered, for example, in the frame- work of “Dvina TM” research project. Unlike a chemical engine, in which energy is released from chemical bonds, the energy for accelerating the working fluid by an electric jet engine is supplied from outside. Solar batteries are the most widespread energy source in near- earth orbits, where the amount of solar radiation is sufficient to meet the energy needs of a spacecraft. Solar batteries are sensitive to radiation, damage accumulates in their internal structure and their characteristics degrade. Therefore, there is a need to account for the radiation dose accumulated during the execution of the transport operation and to evaluate the reduction in the efficiency of solar batteries. Uneven irradiation intensity in the radiation belts formed by the Earth’s magnetic field (Van Allen belts) can be taken into account if the assessment of the radiation intensity at the trajectory points of the maneuver is made using the Earth radiation belt model. The paper proposes a method that allows taking into account the effect of ionizing radiation on the degradation of solar batteries when performing a transport operation using an integrated propulsion system based on a liquid- propellant rocket engine and an electric jet engine, taking into account the chosen trajectory and the model of the Earth’s radiation belt.
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Evaluation methods of the effectiveness of human capital use in the organization
Статья научная
The use efficiency of organizational human capital is considered as a background of organizational added value implementation. The most known methods of the use effectiveness of human capital are discussed and analyzed.
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Evolutionary algorithm for automatic generation of neural network based noise suppression systems
Статья научная
We propose using neural network technology to noise suppress in information signals. Neural networks are automatically generated and adjusted with an evolutionary algorithm. It is shown that the evolutionary algorithm provides a reliable noise suppress system.
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Evolutionary design of neural networks for forecasting of financial time series
Статья научная
The problem offorecasting in various technical, economic, and other systems is an important problem of nowadays. The methods of artificial intelligence and machine learning analyze very effectively various data including financial ones. The main problem of such techniques is the choice of model structure and the configuration of its parameters. In this paper we propose an evolutionary method for the neural network designing that does not require any expert knowledge in the area of neural networks and optimization theory from the user. This algorithm has been applied to the FOREX forecasting task of 13 different currency pairs based on the historical data for 12,5 years. The performance of the proposed algorithm has been compared to the forecasting results of other 6 algorithms. The proposed algorithm has shown the best performance on more than half of the tasks. On remaining tasks the algorithm yields slightly to the multi-layer perceptron trained by the particle swarm optimization algorithm. However, the predominance of the proposed algorithm is more significant.
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Статья научная
Numerical values of factors of viscosity, elasticity and plasticity of a media are established. Experimental dependences of viscosity and elasticity of environment on degree of its filling and granularity of abrasive grains are revealed.
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Express-assessment of business value for making tactical decisions in management of companies
Статья научная
The management of enterprise value by the method of express-assessment of business value is considerate in this work. The author offers a more accurate formula for calculating the business value by net assets. Also we introduce a system of quadrants, that enable to make management decisions in order to increase business value efficiently.
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Статья научная
In this paper the approach for external boundary of pole localization region formulation for transfer function with interval-given parameters is proposed. The boundary is formulated as analytic piecewise function of characteristic polynomial parameters of the given transfer function. Analytic formulation of external boundary of poles localization region allows to reduce computations since existing methods require iterative numeric calculations of characteristic equation roots with fixed step size for edges mapping or full interval root locus mapping as well. Formulated boundary allows to clearly describe system behavior and calcu- late variation ranges of performance indexes. In addition, piecewise function that constrains gives new opportunities for parametric controller synthesis for systems introduced by transfer functions with interval-given parameters. The results can find its practical application in aerospace engineering problems of mathematical analysis and syn- thesis for highly-precise systems of self-direction missiles. In the research the boundary formulation is performed for third order transfer function. Transfer function order was chosen due to the fact that many physical systems and objects can be described mathematically with the third order transfer function, e.g. model of missile target-seeking head with gyro stabilized drive is described with this model. The research was performed on the basis of the following step sequence: firstly, analytical solving of cubic equation applying Cardano’s formula; secondly, interval root locus edges functions obtaining, next external vertexes set obtaining and, finally, external border formulation and plotting.
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Factor analysis of inelastic electron scattering cross section spectra of iron monosilicide FeSi
Статья научная
The inelastic electron scattering cross-section spectra of FeSi silicide were calculated from the experimental re- flected electron energy loss spectra as the product of the average inelastic mean free path and the differential cross section of the inelastic electron scattering. To inelastic electron scattering cross-section spectra study, factor analysis was used. This method allowed us to quantitatively separate the surface and bulk contributions to the spectra, and de- termine the energy of the bulk plasmon more accurately than it is possible using traditional methods. Inelastic electron scattering cross-section spectra (Kλ-spectra) are the products of the average inelastic mean free path λ and the differential inelastic scattering cross-section K (E0, E0 - E), where E0 and E are the energies of the pri- mary and reflected electrons, respectively. The advantage of inelastic electron scattering cross section spectroscopy is that, unlike the reflected electron energy loss spectra, the Kλ-spectra exclude losses due to multiple excitations, and the intensities are determined in absolute units. These spectra are also more sensitive to changes in the energy of the pri- mary electrons and the angle of emission. Inelastic electron scattering cross-section spectroscopy allows to determine the element composition with much greater accuracy than the traditional method of reflected electron energy loss spec- troscopy. In this work, factor analysis is used to study the inelastic electron scattering cross section spectra of the FeSi sili- cide. This method allowed to solve the actual problem of separating spectra into contributions of a different origin, quantify them and determine the energies of a bulk plasmon more accurately compared with traditional methods. The study of electron energy loss processes by isolating contributions of different origin in the inelastic electron scattering cross section spectra is one of the urgent problems of electron spectroscopy, which can be used to assess the effect of surface excitations in REELS, XPS and AES.
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Factors of sustainable development of the agro-economic system
Статья научная
Reserves and factors which ensure stabilization and subsequent sustainable development of agro economic system are analyzed. The priority direction of sustainable development policy of agro-economic system, which is based on five interconnected components, based on the use of economic tools of nature-conservation activity of agricultural tenant farmer stimulation is emphasized.
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Fault tolerant CMOS realization of a minority function for aerospace computer complexes
Статья научная
In recent years, increased attention is paid to the reliability of the critical applications of digital equipment. Reliability means radiation resistance of digital equipment. For aerospace computer systems it is extremely urgent to develop radiation-resistant components. It is one way to ensure that the radiation resistance is the creation of a special archi- tecture - RHBD (Radiation Hardened by Design). This approach includes triple redundancy (Triple Modular Redun- dancy, TMR). In implementing the triple redundancy to increase radiation resistance in the Xilinx FPGA Virtex used majoritarian elements based on a tristate buffer. One of the issuance of majority vote circuit for the loading sign to the pins of the FPGA is using a minority voting function. This feature ensures channel disconnection different from the other two. Only in this case, there is no conflict of signals at the outputs of buffers. Then it was realized majority func- tion (voting by a majority). The FPGA logic elements LUT (Look Up Table) werer used for it. However, in this case FPGA logic resources were spent. CMOS implementation element vote on the minority was described. The paper proposes a fault tolerant CMOS implementation of minority voting function as separate elements in order to improve the performance of redundant circuits and do not use FPGA logic resources. Simulation of CMOS voting member in the minority is made in the circuit simulation of National Instruments Electronics Workbench Group system. Simulation confirms efficiency of the proposed element, and evaluation of the probability of failure-free operation shows its high efficiency. Winning there is a considerable range of probabilities as opposed to triple scheme that gets worse unre- served already at the probability of the order of 0.88.
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Features of electroactivated water production at a coaxial electrode location
Статья научная
Important characteristics of any product are quality and reliability. One of the factors affecting product reliability is the surface cleanliness provided by flushing with liquids. Electroactivated water and aqueous solutions can be used as liquids. On the basis of domestic and foreign experience, leading experts have developed methodological instructions for the widespread implementation of electro-activated water and aqueous solutions in instrument-making and mechanical engineering. For the production of electrochemically activated water and solutions, non-flowing and flow- through modular elements, as well as universal installations, have been developed. Analysis of the structures of these devices has shown that flat metal plates are used as electrodes, therefore there are volumes of water that are subjected to uneven electrical effects. As a result, the specific energy consumption for obtaining activated water is significant. The purpose of the work is to reduce the specific energy consumption in the production of activated water and aqueous solu- tions. Coaxial arrangement of the electrodes leads to reduction in energy consumption. The study of the electroactiva- tor of water with a coaxial arrangement of electrodes allowed us to establish the optimal ratio between the volumes of anolyte and catholyte and the time of electrolysis of water and an aqueous solution of sodium chloride. A new indicator of efficiency (the specific energy consumption per unit of change in the pH of water or an aqueous solution) objectively reflects the perfection of the design of electroactivators. The research results can be used in instrument and mechanical engineering.
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Features of operational costs decomposition by carrying out of ship-repair works
Статья научная
Types of costs decomposition at the ship-repair enterprises are offered, considering individual character of works and allowing improving qualitative characteristics of cost management.
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Features of synthesis of composite material based on silicon dioxide and carbon nanotubes
Статья научная
Today, there are many papers showing the effectiveness of the use of carbon nanotubes as additives to composites. Their use in polymers is especially successful, but the efficiency of their use in ceramics poses many questions. The aim of the work was to study the effect of the addition of carbon nanotubes on the properties of ceramics. For this purpose, pure silica, obtained by the hydrolysis of tetraethoxysilane in an alkaline medium, was taken as a model. The obtained granules of the material were well sintered at 900 ° C and it was decided to compound this material with carbon nano- tubes. Depending on the method of introducing, the result turned out to be diametrically opposite. Nanotubes intro- duced during the synthesis of silica played a role in the formation of silicon dioxide grains and effectively compacted the material, increasing its hardness. On the contrary, nanotubes grown in ceramic pores wedged the grain of silicon dioxide, making the material softer. In the first case, it is important to note that the synthesis of ceramics is not affected by the synthesis of nanotubes. In turn, nanotubes always affect the process of forming ceramics. This influence leads to a change in the structure of the grains of ceramics, and as a consequence of the mechanism of interaction between them, which in turn changes the density and strength of the ceramics. In the second case, in order to grow nanotubes in the pores and cavities of the ceramic material, one must first im- pregnate the ceramic material with a catalyst. Thus, there is a requirement for a precursor of the catalyst - the absence of its interaction with ceramics. The second requirement is for inertness of the ceramics, both to the catalyst and to the entire synthesis process. In addition, it is necessary that the structure of the pores does not change during the synthesis, i.e. they did not close during the synthesis of nanotubes, but provided transportation of the starting materials and reac- tion products. Therefore two mechanisms that affect the formation of a composite ceramic material have been described. The described composite can be used in the rocket and space industry for compounding ceramic fairings and thermal insu- lation.
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Features selection for text classification based on constraints for term weights
Статья научная
Text classification is an important data analysis problem which can be applied in different domains including airspace industry. In this paper different text classification problems such as opinion mining and topic categorization are considered. Different text preprocessing techniques (TF-IDF, ConfWeight, and the Novel TW) and machine learning algorithms for classification (Bayes classifier, k-NN, SVM, and artificial neural network) are applied. The main goal of the presented investigations is to decrease text classification problem dimensionality by using features selection based on constraints for term weights. Such features selection provides significant reduction of dimensionality and less computational time for calculations. Besides, the use of constraints for term weights could increase classification effectiveness. We have observed such increase for three out of five problems. In the remaining two problems, no significant change and a decrease of classification effectiveness was observed.
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