Статьи журнала - Сибирский аэрокосмический журнал
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The theory of real options in the estimation of consecutive innovative projects
Статья научная
Approaches to the estimation of efficiency of the investment projects including consecutive improving innovations are considered, the choice of methodology of real options for the estimation of such projects is proved and its application is shown by the example of an abandon option for the project.
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Статья научная
The applications of space vehicles in the modern world are extensive enough: satellite communication, broadband and narrowband broadcasting, meteorology, scientific research and others. For this reason, modern space vehicles use the latest achievements of science and technology. It allows us to create easy, compact space vehicles with a wide functional. The devices developed in the Research and Production Center “Polus” should meet the requirements of advanced reliability both for regular and for emergency operating modes. One of the scopes of application of such devices is designing of space vehicles. The main task at designing and manufacturing of devices and their components is reliability maintenance. This is a primary requirement to custom-made products for which repair at major failures is extremely labor-consuming. At the same time, serious demands are made to mass, dimensional characteristics, power consumption, payloads, noise characteristics of separate blocks and devices, and other technical parameters. However, it is necessary to consider that at high requirements to characteristics the process of creation of products should be technological. There are various techniques to define reliability of technical devices and their components. One of such ways is carrying out the whole complex of tests simulating a full cycle of operation of the device or a mechanism. However, experimental techniques have essential disadvantages, namely: high cost and long duration. Mathematical modelling allows us to reduce expenses on mock-up designing, engineering time, risks, to reveal weak points, to develop recom- mendations for strengthening the design and to give preliminary conclusions about firmness of the device to loads. Along with thermal, electrostatic and frequency characteristics, mechanical effects play an important role, i. e. dynamic and static loads. In this paper, the results of modelling of external mechanical effects on the device are pre- sented. Numerical modelling of quasi-static loading and effect on the device of random vibration is conducted and the modal analysis is carried out. Oscillation modes of the first three resonant frequencies of the device, stress, displace- ments and accelerations diagrams are obtained. Load factors, the maximum values of displacements and accelerations at impact actions are determined.
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To geostationary collocation problem
Статья научная
This article is about geostationary collocation problem which means problem of cooperative station retention. As part of this task it is assumed that different control centers don’t exchange information about kinematic parameter’s vectors and maneuvers. So there is full information and control possibility for one collocation member only. Sets of kinematic parameter vectors are available for the other collocation members. This situation corresponds to lack of a priority information conditions, so there is f nonparametric uncertainty situation because due to absence of informa- tion on parametric control law which is used to choose maneuvers for other collocation members. Modern collocation theory doesn’t allow to avoid collision and process station retention in this condition. Synthesis of nonparametric regu- lator is in contemplation to solve this problem. First task of this regulator is estimation of previous maneuvers by proces- sing kinematic parameter vectors sets. Second task is estimation of coordinates for every collocation member. Finally, nonparametric regulator must synthesize control which allows to process station retention and collocation. Suggested algorithm belongs to nonparametric class, so it is not necessary to know parametric form of controlling law. It is based on modification of Nadaraya-Watson nonparametric estimation. The geostationary movement model including main perturbations, and most common collocation approaches are suggested. Nonparametric control algorithm is proposed.
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To nonparametric identification of dynamic systems under normal operation
Статья научная
The problem of nonparametric identification of linear dynamic objects is being investigated. In contrast with para- metric identification, the case is analyzed when equations describing a dynamic object are not specified according to the parameters. Moreover, the identification problem is analyzed under normal object operation, opposite to the previ- ously known nonparametric approach based on Heaviside function input to the object and further Duhamel integral application. An arbitrary signal is inputted to the object during normal operation and weight function realizations are represented by observations of input-output object variables measured with random interferences. As a result, we have a sample of input-output variables. As linear dynamical system can be described by the Duhamel integral, with known input and output object variables, corresponding values of the weight function can be found. This is achieved by dis- crete representation of the latter. Having such realization, nonparametric estimate of the weight function in the form of the nonparametric Nadaraya-Watson estimate is used later. Substituting this into the Duhamel integral, we obtain a nonparametric model of a linear dynamical system of unknown order. The article also describes the case of nonparametric model constructing when a delta-shaped function is inputted to the object. It was interesting to find out how delta-shaped function might differ from the delta function. The weight function was determined in the class of nonparametric Nadaraya-Watson estimates. Nonparametric models were investigated by means of statistical modeling. In general, nonparametric models have shown sufficient efficiency in terms of accuracy prediction by nonparametric model in relation to the actually measured output of the object. Evi- dentally, the accuracy of nonparametric models reduces with the growing influence of interference from the meas- urement of input-output variables or the discreteness of their measurement. Previously proposed nonparametric al- gorithms consider the case when Heaviside function was applied to the object, which narrows the scope of nonpara- metric identification practical use. It is important to construct nonparametric model of a dynamic object in condi- tions of normal operation.
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To the problem of nonparametric robust estimation of the regression function on observations
Статья научная
There are parametric and nonparametric statistical models in the literature. These models differ from each other in levels of the prior indeterminacy in the statistical description of observations. The difference in ways these models were created tends to smoothing by introduction of transition models. It is explained by the fact that a statistical model, as well as any other model, is inevitable idealization and it can be only successful approximation of actual processes at its best. Emphasizing this fact, Box writes: “All models are irregular, but some of them are useful”. When using statistical procedures it is desirable to have information about what deviations have a decisive influ- ence on the final conclusion at statistical analysis. In case the true distribution is not normal, there can be questions of normal theory reference procedures applicability. The recent research approach called “robast statistics” and offered as “third generation statistics” after parametric and nonparametric statistics by American mathematician J. Tyyuki is devoted to answer formulated above questions and create statistical procedures insensitive to deviations from assump- tions. A number of publications on this approach constantly increases, there are already monographs, among them the first book of Hyubera, the book by F. Hampel and others, educational literature is also available. The “robust” term, which corresponds to the definition “rough, strong”, was introduced into statistical literature by Box in 1953 and since the middle of the sixtieth this term has became conventional for the section of statistics where statistical procedures insensitive to deviations from the accepted model assumptions develop. The robust idea has had a long history, which was described in Stigler’s work. It appears in the work of K. Gauss, S. Newcomb, A. Eddington and others. However systematic development of robust ideas began with J. Tyyuki’s works and, especially, after the work of Hyuber in 1964. In this work an estimation of functions with a data outlier problem is given. In case of nonparametric indeterminacy the following steps are used to solve the problem: 1) the type of regression function with input data is set; 2) function estimation is applied. We suggest the following reliable robust nonparametric estimation approach. The main idea is to exclude the data which can affect estimation.
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Статья научная
The article deals with the functional and algorithmic implementation of multi-version execution environment of modules as components of the onboard software of autonomous pilotless objects by means of real-time operating system. One of the approaches to implementation multi-version execution environment - implementation of the princi- ple of a pseudo-parallelism (imitation of concurrent execution of tasks by dividing the time of their execution) are given. Messaging process between multiple tasks implemented by cycloram, as the procedure of returning of voting result by queuing mechanism.
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To the question on innovative development of the Russian economy
Статья научная
Several conceptions of innovation methodology, formed on the institutional level are being reviewed. Their level of methodological interpretation and the possibility of their use as a base for development of methodological instruments are being analyzed.
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To the task of controlling a group of objects on the basis of information technologies
Статья научная
To participate the TPP with cross-section communications in the general primary frequency control, it is necessary to have a working main regulator. The main regulator is designed to maintain the steam pressure in the major steam line of the TPP at a given level, which is a difficult task. At the TPP with cross-connections, the steam produced by the boilers enters the major steam line. To maintain the pressure in the major steam line, it is necessary to control the heat load of the working boilers. Traditional solutions to construct the main regulator found no use, as have a number of disadvantages, not allowing exploiting a system of automatic control. Looking at the steam pressure control system in the major steam line from the bottom to up, it is possible to identify disadvantages that prevent the effective operation of the main regulator at each level. At the lower level of the main regulator, there are controllers of heat load of boilers, built according to the scheme task-heat. Heat load controllers are designed to maintain heat release in the boiler fur- nace at the required level. The heat signal is the sum of the signals for the steam flow of the boiler and the rate of change in the steam pressure in the boiler drum. Such a structure does not allow maintaining the invariance of the heat signal under external disturbances effectively, as sharp changes of the steam pressure in the major steam line lead to a "false" operation of the controllers. At the upper level there is the main regulator itself, which maintains the steam pressure in the major steam line at a given level and corrects the tasks to the controllers of the heat load of the boilers. The simultaneous identical effect on the heat load of the boilers cannot be optimal from the point of view of the criteria for assessing the quality of regulation, since the dynamic properties of the boilers, such as the gain, the transition time constant and the transport delay are individual for each boiler. However, in 2006-2008, the attempt to build an updated main regulator that takes into account the shortcomings of the traditional scheme was made. The basis of the structure of the main regulator is still parametric and, as a result of ten-years’ experience, shortcomings in the operation of the updated main regulator were identified. The shortcomings, in most cases, consist in need of frequent corrections of adjusting coefficients of system because of the change of dynamic properties of an object during the operation. In fact, the same problems related to the parametric structure of the regulator remain. Up-to-date information technologies made it possible to introduce adaptive process control systems that allow to count an extended number of signals entering the system and to form control actions, based on both current and historical data of the technological process. The use of the latest information technologies and modern hardware in the control of complex multi-connected units that solve not only the problems of process control, but also the problem of improving the economic and environmental performance of enterprises, should become a new step in the development of automatic control systems.
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Tools of biotechnological sector formation in the region
Статья научная
At the present time in the world economy a constant increase of importance and influence of hi-tech branches takes place. As a result, appears the natural need in research of various scientific-technological development mechanisms, which correspond to modern views on scientific-technical progress.
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Transparent heaters based on the copper micromesh passivated by graf(ph)ene oxide
Статья научная
The paper presents the results of creating and researching the transparent heaters with enhanced performance characteristics. The heaters are based on a composite coating of a new type by contrast with classical solutions based on transparent conductive oxide films. Such a composite coating is copper micromesh obtained using a self-organized template, stabilized by a thin film of graphene oxide (GO). The micromesh coating is formed by magnetron sputtering of copper onto a template obtained as a result of self-organized cracking of a silica film. Then, a graphene oxide film protecting the micromesh coating from thermal and chemical degradation is applied to the micromesh coating by the spray-method. A composite coating with the surface resistance of 8.9 Ohm/sq is obtained with the transparency of 82.8 % at the wavelength of 550 nm. High uniformity of heating and stability of the composite coating are shown when operating under heating up to 97.2 °C for a long time (24 hours). The composite coating of the GO / Cu micro- mesh on a glass substrate 2 mm thick is characterized by the thermal resistance value of 134.2 °C·cm2·W-1, while the ITO literature sample on an equivalent substrate is characterized by the thermal resistance of 94.04 °C·cm2·W-1, which indicates higher heating efficiency at the same specific power dissipation. This fact opens up prospects for its use as an anti-icing coating in aerospace industry.
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Two-dimensional thermal model of the thermal control system for nonhermetic formation spacecraft
Статья научная
Based on the proposed computational model including a two-dimensional system of equations of thermal balance characteristic of the surface of thermal control system of nonhermetic formation spacecraft the algorithm and the cal- culation program of the temperature control system are developed. It allows to calculate integrated thermal parameters and conduct simulations of the system response. We consider the case of a two-dimensional problem, when arising tem- perature gradients in the transverse direction (Y-axis) and longitudinal direction (X-axis) is taken into account, while the conductive heat transfer inside the skin along the X-axis of the profile of the liquid circuit of the thermal control system is neglected. In this case the transverse gradient (along the Y-axis) is formed by Fourier heat conduction equa- tions through characteristic surfaces, while the longitudinal gradient (along the X-axis) is determined by the heat and mass transfer processes by the refrigerant flow in the liquid ring circuit. The number of docking thermal balances (equations) and, accordingly, the determined temperatures are correlated by the constructive elements of the spacecraft thermal control system: radiation surfaces (N - North, S - South); structural honeycomb panels; heat pipes; liquid circuit.
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Two-level genetic algorithm for X-ray powder diffraction structure analysis
Статья научная
A new evolutionary approach for crystal structure determination of powders based on X-ray diffraction full-profile analysis and genetic algorithm of global optimization is suggested. An investigation of efficiency of given algorithm is carried out on test real-world problems of structure determination.
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Статья
In this paper we describe and investigate the two-steps system sorting out inappropriate words in searching of similar words in the lexicon for automatic concatenation of Russian sub-word units. This two-steps system consists of com- puting the Levenshtein distance on the first stage and computing the similarity coefficient by the relevance function on the second stage. We also compared the performance of the Wagner-Fisher algorithm and the suggested algorithm
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Use of conservation laws to solve the problem of load wave in an elastoplastic rod
Статья научная
The process of propagation of plastic deformations in a semi-infinite elastic plastic rod caused by dynamic loading applied to the end of the rod, which is not decreasing in time, is considered. The equations are written in the Lagrangian coordinate system. It is assumed that during deformation there is no lateral bulging of the rod and that the influence of transverse deformations of the rod on the process of propagation of longitudinal waves is negligible. At the initial moment, the rod is in a deformed and dormant state. Small deformations of the rod are considered. The density of the rod during deformation does not change. The only non-zero component of the stress tensor will be the component along the ox axis, non-zero components of the strain tensor will be the components along the Ox, Oy axes. As a result, a system of two quasilinear first-order homogeneous equations is constructed. The equations are hyperbolic. They are built for performance and ratio on them. Next, the equations are written in terms of Riemann invariants. For the equations constructed, the conservation laws are found in the case when the current remaining depends only on the functions sought. As a result, a system of linear equations with coefficients depending only on the required functions is obtained. Тhe construction of conservation laws is reduced to the solution of the boundary value problem for the known Euler-Poisson-Darboux equations. This problem is solved with the help of Riemann functions. The conservation laws allowed us to find the coordinates of the points of intersection of characteristics, and thus to solve the problem. In conclusion, the article considers the case when one of the characteristics crosses the line on which the initial conditions are given. In this case, as is known, the Cauchy problem cannot be solved. This leads to a procedure which, with the help of conservation laws, makes it possible to find out the solvability of the Cauchy problem. It is reduced to the solution of a simple integral equation by the method of successive approximations.
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Статья научная
The article considers the content of the course of post graduate students’ training in a foreign language for scientific purposes in a technical university of aerospace profile. The experience of work in the context of SibSAU training of young scientists to effectively functioning in an international professional scientific community is analyzed. The experience of work in connection with the growing trend of writing scientific texts (articles, publications, monographs, etc.) in a foreign language (English) is presented. A complex structure of work with postgraduate students in teaching a foreign language for scientific purposes is developed and presented. Particular attention is paid to the integration of Internet resources in the process of preparing for the candidate's exam in a foreign language, and subsequent publications in international scientific systems such as Web of Science, Scopus. The article reflects the experience of testing and implementation of various Internet sources, presents the most effective ones. High cognitive professionally-oriented and didactic potential of the Internet technologies used is marked.Particular attention is paid to the scientific search systems, allowing a full-text search on articles of major foreign publishers’ magazines, articles in the archives of articles and preprints, scientific resources of Internet. Links for work with authentic scientific periodicals, modern dictionaries and encyclopedias are proposed. The article maybe of interest to postgraduate students of technical universities of aerospace profile, preparing for the successful functioning in the scientific community in order to accommodate their publications in leading peer-reviewed journals, as well as for foreign language teachers using in integrated methods in teaching a foreign language for scientific purposes.
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Статья научная
The article reveals new methods of effectiveness increase in teaching foreign languages to technical students using information and communication technologies and their practical implementation at the premises of the Foreign Languages Resource Center of Siberian State Aerospace University. Adoption of information and communication technologies to the educational process is based on students’ independent language learning that encourages more productive development of language competences mastered by students and future specialists in a special area of technical knowledge as a whole.
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Using genetic programming techniques for inertia-free system identification tasks
Статья научная
The problem of identification of inertia-free objects is being investigated. The overall pattern of the process investi- gated is being described. As a research object, a stochastic inertia-free process of modeling has been chosen. A feature of the process under consideration is the fact that unmanaged but controlled variables influence the process under investigation. In addition, the process under investigation is affected by unmanaged and uncontrolled variables. The levels of priori information has been briefly considered and characterized. For each level of priori information the identification method has been described. Particular attention is paid to the levels of priori information under which the identification task in a “broad” sense needs to be addressed. As a method of identification, genetic programming is considered. Method of genetic programming has been chosen as a research object since this method is more commonly used in the identification problem. Despite the frequency with which this method is used, it is interesting to look at the results of this method under different conditions. As changing conditions, the object’s complexity and the change in the volume of the training sample were used. For the identification process, objects with different structures were selected. The dependence of the time of finding the structure of the object on the size of the training sample was investigated. As shown by studies, there is no clear correlation between the time of finding the structure of the object and the size of the training sample. In addition, relationship between the time of the structure and the “complexity” of the object was investigated. As a criterion of “complexity” of the object, the number of input variables was taken. The study showed correlation between some values; with the increase in the number of input variables, the time of finding the structure of the process also increased.
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Using signals of navigation satellites in the monitoring of the earth covers
Статья научная
The features and capabilities of remote sensing of earth covers by means of signals of navigation satellites are pre- sented. The methods of reflectometry of the surfaces of earth covers and radioscopy of forest canopy are described. The options for using the signals of GLONASS, GPS systems are considered. Test measurements of interference diagrams were carried out on 5 test platforms from heterogeneous soil surfaces: salt marshes and asphalt; water surfaces of sa- line and freshwater bodies in summer, including ice cover of small thickness in the period of autumn freeze-up. The method of radioscopy helped obtain the data on the spatial and temporal characteristics of attenuated signals of the GLONASS and GPS satellites in the pine forest. Estimates of the linear attenuation coefficients of the signals passing through a forest canopy with a coordinate reference were made. The results obtained are the basis for the development of methods and technologies for continuous monitoring of the characteristics and state of earth covers by means of sig- nals of navigation satellites for solving a wide range of applied tasks.
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Verification of finite-element model spacecraft via test results
Статья научная
The question of ensuring strength, durability and survivability of a spacecraft construction with mathematical mod- eling complexes is a modern trend in satellites design. This approach is based on the shortening of the prelaunch preparation stage. In particular, this is due to the reduction in the number of vibration tests of a spacecraft (SC). In the present work, using the example of vibration tests of “Express-1000K” service system module, we consider the verifica- tion technique for the mathematical model of communication satellites, output by a pair of payloads. The choice of this research object was caused by the conceptual scheme for modern space vehicles constructing, based on the modular principle. The service system module is the basic supporting structure of the spacecraft, able to integrate with any pay- load (information support, scientific research, geodesy and remote sensing, navigation) and is a universal tool in a sat- ellite construction. In tests with harmonic vibration, the first longitudinal and transverse tone of the spacecraft oscilla- tions are well identified, which can be fairly easily predicted applying the finite-element model. Proceeding from this, the accuracy of forecasts depends, to a greater extent, on the complexity of the modeled construction and the modeling procedure being used. The study provides a finite-element modeling technique for spacecraft output by a pair of pay- loads; the dynamic characteristics of the object of investigation by calculation and experimental methods are obtained. The identification procedure was carried out using the ‘modal consent’ method. The verification technique considered in the study makes it possible to carry out effective adjustment of the finite-element model. The finite-element model obtained by verification results allows to effectively evaluate the behavior of a spacecraft already at the design stage, which enables to shorten the time of vibration tests. The main results of this research were applied in verification of mathematical models of modern spacecraft developed by JSC “ISS”. The importance of applying verification methods of the mathematical model of the product at the preliminary (design) stage of spacecraft creation was noted.
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Video based flame detection algorithm
Статья научная
Video based flame detection from a surveillance camera offers early warning to ensure prompt reaction to devastat- ing fire hazards. Many existing fire detection methods based on computer vision technology have achieved high detec- tion rates, but often with unacceptably high false-alarm rates. This paper presents an automatic flame detection method using computer vision and pattern recognition techniques. This method uses the features of fire, such as the moving parameters, chromatic components, and geometrical (flickering) features. For experimental researches the databases of Bilkent University and Dyntex database were used. The developed method of flame detection on video provides 89.5-98.2 % of accuracy for flame sequences. The number of frames of test video sequences was 6.853, the total duration of the videos is 5 minutes. Experimental results show that the proposed method is feasible and effective for video based flame detection.
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