Статьи журнала - Сибирский аэрокосмический журнал
Все статьи: 3160
About the model of the active system
Статья научная
The problem of the active system modeling is researched. There are three sources of information to construct the models. The first source is the theory of the problem, the second one is experts in the field ofproblem, and the third one is data bases. The method considered in this article uses the third way. The nonparametric algorithm for modeling active element in the system is proposed. The results of the computer experiments are published.
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About torsion of parallelepiped around three axis
Статья научная
The theory of limit state deals with statically determinate condition of solids. In this case the system is closed due to extreme conditions, such properties of matter such as viscosity, elasticity, etc. cannot influence the limit state. In other words, when reaching the limit state the nature of the relationship between stress and strain has no effect on the ulti- mate state. The study of such systems has been consistently pursued by D. D. Ivlev and his coauthors. To the equilib- rium equations they attached two or an equation relating the components of the stress tensor. This led to the closure of the system of equilibrium equations. In the theory of plasticity equations, which are closed with a single yield stress are studied well. The most well-known system describing the ultimate state of deformable bodies are well-studied equations describing the torsion of the plastic bodies, the two-dimensional stationary problem of the theory of plasticity. The arti- cle discusses some other systems of equations which are closed only by one equation of flow, which corresponds to the classical theory of plasticity. It is assumed that the components of the velocity vector depend only on two spatial coor- dinates. In addition, for the component of velocity vector conditions of deformations compatibility are performed identi- cally. The constructed systems can be used to describe the twisting of the parallelepiped around the three orthogonal axes. For the constructed system of equations point group symmetries, conservation laws have been found. It is shown that the system allows 8 -dimensional Lie algebra. On the basis of the symmetry group some classes of invariant solutions of rank 1 have been constructed. They depend on arbitrary functions of one variable. It is shown that these solutions can be used to describe plastic torsion of a parallelepiped around three orthogonal axes. It is shown that the system admits infinite series of conservation laws. The concluding paragraph describes the construction of elastic solutions to the problem. It is shown that it boils down to finding three harmonic functions.
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Active metamaterial on the base of integral NEMS-structures
Статья научная
The conception of integrated nanoelectromechanical systems (NEMS) formation method is considered. The method is based on original combination of self-organizing and self-aligning processes. The functionality of proposed NEMS-structures and possible applications of nanomaterial which constituted by two-dimensional array of such structures are discussed. The results of experiments directed to proposed NEMS-technology realization are led.
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Статья научная
One of the most important aims of air traffic control is continuous positioning of aircraft, which makes it possible to control a given flight plan and record deviations from the route, along with organizing search and rescue operations in case of an accident or a disaster. Great difficulties arise when performing this task in areas where there is no radar station in the mountains, forests, at high latitudes or at extremely low altitudes. This problem can be solved by using satellite navigation systems, satellite communication systems and automatic vehicle monitoring. In order to communicate with the control center, it is advisable to transmit data packets of up to 340 bytes contain- ing information about the location of the aircraft and its status. This can be done via GSM mobile networks, and in areas where there is no communication of this kind, via the satellite communications system “Iridium”. To put these two possible ways of communication into practice, the aircraft must have on board an ASC-6 GLONASS / GPS terminal (a vehicle-compatible modification), which determines location, speed and heading of the aircraft. It is also able to reg- ister a number of other parameters, such as the status of the analog / discrete inputs, and RS-232 connected sensors indications. This makes it possible to transmit to the control center not only the geographical position data, but also the speed of the aircraft and other operational data. A special communication module SM-1 can be used to support the sat- ellite communication, as it is ASC-6 compatible through RS-232 interface.
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Статья научная
A program-realized coordinated algorithm of choice for automatic excitation regulator settings has been developed. This algorithm is based on the resultant theory and applies a mathematical model which is synthesized by experimental frequency characteristics of an electric power system.
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Algorithmic and software of the system profiling the actions of users of the information system
Статья научная
The paper describes the software of the system for profiling the actions of users of the information system. This profiling system is aimed at solving the problem of trust in users of information systems. The system should regulate access to protected resources by analyzing user behavior. The algorithmic component of the system is represented by a user behavior model and a general system operation algorithm. The user behavior model is based on the apparatus of Markov chains Software implementation allows in practice to obtain the foundations of the proposed approach to work. At the development stages, the choice of software architecture is carried out. The client-server architecture was chosen as a reasonable decision. The software component of the user activity profiling system consists of five separate software modules. At the end of development, a brief testing of the components is carried out. The novelty of this work lies in the proposal of an approach that uses the profiling of user actions as an additional determining factor in managing access to objects, as a way to strengthen the basic measures “Controlling access of subjects to access objects” in the order system of FSTEC of Russia.
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Algorithms for calculating complex indicators in dynamic structures of data representation
Статья научная
This paper presents algorithms for calculating complex indicators on set factual data, represented in dynamic structures with the application of the graph theory.
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Статья научная
A new algorithm for the solution of complex constrained optimization problems based on the probabilistic genetic algorithm with optimal solution prediction is proposed. The efficiency investigation results in comparison with standard genetic algorithm are presented.
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An algorithm for an object grasping by a manipulator in an unknown static environment
Статья научная
An algorithm for a n-link manipulating robot (MR) control in an environment with unknown static obstacles is considered. A theorem is proved which states that following the algorithm a MR in a finite number of steps will either grasp an object or will give a proved conclusion that an object cannot be grasped in any configuration.
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An analysis of intelligent methods and algorithms for unlabeled data processing
Статья научная
Intelligent algorithms and method is well-suited to many problems in data processing, where unlabeled data may be abundant. We survey previously used selection strategies for intelligent model, and propose two novel algorithms to address their shortcomings, focus on Active Learning (AL). While has already been shown to markedly reduce the annotation efforts for many sequence labeling tasks compared to random selection, AL remains unconcerned about the internal structure of the selected sequences (typically, sentences). We propose a semi-supervised AL approach for sequence labeling.
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Статья научная
He authors propose an approach to research tests of copra-spring stand, designed for testing rockets and space- craft on inertial forces of a pulse character. The authors present the design of the stand, consisting of two main parts: mobile and stationary. The authors present a method for calculating the magnitude of the load factors and the oscillation frequency of the test object, and calculate the parameters for adjusting the spring stiffness. They describe the possibility of carrying out dynamic tests for imitating transient loads that hermetic structures such as modules of habitable orbital stations, loaded by internal pneumatic pressure, withstand during their lifecycle. The authors present the results of research tests when the stand without any additional weight was falling from the height of 20, 35 and 50 mm. They determine the levels of axial and transverse accelerations on the envelope of the stand and the lower ring. A comparison of the original and filtered signal from the load factor sensors obtained in each test case was made. The authors present the results of calculating accelerations of the moving part of the stand using the video processing of the experiment. To determine the position of the stand envelope they developed special software. The essence of the software was to determine the coordinate of the border of the color change from the frame height from a light color to a darker one using averaging in rows. The authors show that the results of a comparison of man- ual frame-by-frame measurement and data obtained by the software method indicate a sufficient convergence of the results using a drop from the height of 20 mm experiment. The comparison of axial loads obtained by various methods is given, when the moving part of the stand is thrown from the height of 20, 35 and 50 mm, respectively. The zero time points for the video and accelerometers were determined so that the first maximum is reached simultaneously. According to the results of research tests, the authors describe the development and validation of the finite element model of the stand. The calculations were carried out in a nonlinear formulation, which makes it possible to correctly take into account the loading of the stand at all stages, using the method of direct solution of the equations of motion. The authors show the results if calculating the time dependences of displacements and load factors at the sensor instal- lation places and a comparison with the experimental results, which shows a good convergence.
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An automatic device for measuring resistivity of the silicon four-point probe method
Статья научная
An automatic device for measuring the resistivity of single-crystalline silicon by means of the four-point probe method has been developed.
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Статья научная
The microstructure of a layered polymeric composite material used in the construction of a metal composite over- wrapped pressure vessel is investigated. The purpose of this work was to evaluate the parameters characterizing the structure of a laminate polymer composite material. Due to their technological and structural features, laminated polymer composite materials have a number of operational disadvantages that lead to a reduction in the overall level of strength characteristics. From the different zones of the nine-layer composite shell of the metal composite overwrapped pressure vessel, four vertical flat samples of the composite material for the manufacture of thin sections were cut out. The method of electron-scanning microscopy was used. The analysis of the percentage confinement of fibers in the ma- trix was carried out. The structure of the layered polymeric composite material is uniform with the presence of a dis- persion of distances between the fibers. The analysis of porosity in a composite material was carried out. The analysis of the structure of composite materials with different porosity has shown that with increasing pore area and their num- ber, the strength characteristics of composite tapes and reinforcing fibers decrease. Using the “mixture rule” and “polydispersity model”, the values of the effective modulus of elasticity of the composite material are estimated. It is determined that the modulus of elasticity of the composite material in the zone of the flange of the composite shell is less than at the equator. A complex evaluation of the quality of a laminate polymer composite material used in the structure of a metal composite overwrapped pressure vessel was carried out. The obtained results of inhomogeneity of the me- chanical properties of the composite shell are necessary for design calculation of the stress-stain state of metal over- wrapped pressure vessels.
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Analysis of risks of the foreign trade transactions between Russia and China
Статья научная
The foreign trade transactions in the system of economic activity between Russia and China are considered. Recommendations about conducting the foreign trade transactions with China with the purpose to increase the efficiency of it are resulted.
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Analysis of spacecraft orbital motion stability of Gonets-M No 37152
Статья научная
In the present investigation we envisage the spacecraft motion of Gonets-M (Gn-M) orbit group which is located in a circular orbit at a height of 1500 km with an inclination of 82.5 degrees. Its movement is measured based on the current navigation parameters which reveal its orbital motion analysis. Gn-M has a special characteristic feature of rotation with apsidal motion in frozen orbit. Based on this fact, the present study was carried out with the conception of a frozen orbit of Gn-M by investigating eccentricity parameter e and perigee argument w. The comparative analysis is presented as graphs which indicates the variation in the values of eccentricity parameters e and the perigee argument w which is calculated based on the current navigation parameters and the predicted motion of Gn-M. An orbital meas- urement was carried out by studying three Gn-M of the same orbital plane over a period of one year. The study insight on the complete analysis of specific changing revolution of the nodical period of Gn-M staying at frozen orbit. The am- plitude vibrations of an orbital nodical period are calculated and compared with the orbital parameters of Gn-M which are in the same orbital plane. Overall the results obtained in the present investigation are promising enough which can aid in improving the calculation accuracy of orbit correction parameters of Gn-M.
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Antenna modules of GNSS user equipment: innovative approaches
Статья научная
An original engineering conception of the navigation antenna module design, involving the idea that a dielectric substrate of the antenna element is made of a ceramic in the form of a turned cup provided with the patch on its top and metalized cavity, in which all active elements are placed, is suggested. The cup-shaped antenna element has additional advantages against the patch antenna of a traditional form: it has a wider matching band, higher radiation efficiency, a wider radiation pattern, and a wider (up to 1.5 times) meridian angle range, with circular field polarization. Metamaterial, used in the antenna element of an all-ceramic type antenna module, allows obtaining a circular field polarization even at low elevation angles, which only a quadrifilar antenna has. To work with all operating GNSS systems (in the extended bandwidth), an antenna element, which has two planar axial elements placed on the common substrate, is proposed. The antenna element can also be designed to work in 2 bands, for example, in L1 and L2 GLONASS/GPS or in L1 and L2 GPS/GALILEO. A multi frequency stacked antenna design method with opposite feeding of the antenna elements, which provides the antenna element isolation of more than 25 dB and identical radiation patterns is suggested. It is proposed to use for multipath mitigating a special type of the EBG-metamaterial and, as well, a special method of multipath mitigating ground plane mounting, which doesn’t narrow antenna element radiation pattern and doesn’t spoil phase center stability.
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Статья научная
The strict hierarchical manpower system is modeled in the state space where the desired number of men in particular rank is determined by predefined trajectory function. The transition model is represented by the principles of System Dynamics where each rank is represented as the state element and transition as the flow. The basis for the model is the structure of the exponential delay chain with additional outflows from particular states. The strategy for achieving the desired states is determined by the application of the genetic algorithms which are implemented in JavaScript as well as the System Dynamics model. Parameter boundaries were taken into consideration which was determined according to the historical data. Predetermination of the desired system states by the set of exponential functions reduced the optimization burden. The optimization problem was defined as the minimization of the sum of quadratic difference between desired and actual states in all ranks for the observed time horizon. Time boundaries in considered optimization problem were not constant which contributes to the complexity of the addressed optimization task. The six state finite automaton code realization is described which prevents the oscillations in the strategies. The algorithm for integration of system dynamics model and genetic algorithm with finite automaton is described.
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Статья научная
The estimation of adequate service life of aircraft instruments is a factor of great importance in aircraft operation process. Changing the instrument service interval affects both reliability (shorter intervals make it easier to locate malfunctions of components and assemblies as early as possible) and economic performance (inducing increase of operating costs). So, the increasing the service interval without potentially reducing reliability is an economically im- portant task. To determine the optimal time to maintenance for aviation components and assemblies, it is necessary to determine the span of their service life with the highest degree of precision. The problem of calculating such estimates is compli- cated by the fact that the data on component failures are scattered and incomplete, which makes it difficult to assess their statistical characteristics accurately. The purpose of this article is to find an effective method of statistical characteristics assessment for small samples as the first stage of modeling of the aircraft components and assemblies reliability. It is induced by specific operational factors of aviation components exchange at small airlines operating Soviet-time aircraft. The article examines two methods of resampling, bootstrap and jackknife. There is also an assessment of mean time to failure expectation for fuel gauges, of the variance and root-mean- square deviation in the article. The bootstrap method is offered as applicable for statistical characteristics assessment of mean time to failure ex- pectation for aircraft components and assemblies taken for analysis in small samples (pressure gauges were chosen as an example of such analysis). The assessments and calculations can be used by airlines to state the nonfailure service time of a variety of components and assemblies.
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Applied classification problems using ridge regression
Статья научная
The rapid development of technical devices and technology allows monitoring the properties of different physical nature objects with very small discreteness of the data. As a result, one can accumulate large amounts of data that can be used with advantage to manage an object, a multiply connected system, and a technological enterprise. However, regardless of the field of activity, the tasks associated with small amounts of data remains. In this case the dynamics of data accumulation depends on the objective limitations of the external world and the environment. The conducted research concerns high-dimensional data with small sample sizes. In this connection, the task of selecting informative features arises, which will allow both to improve the quality of problem solving by eliminating “junk” features, and to increase the speed of decision making, since algorithms are usually dependent on the dimension of the feature space, and simplify the data collection procedure (do not collect uninformative data). As the number of features can be large, it is impossible to use a complete search of all features spaces. Instead of it, for the selection of informative features, we propose a two-step random search algorithm based on the genetic algorithm uses: at the first stage, the search with limiting the number of features in the subset to reduce the feature space by eliminating “junk” features, at the second stage - without limitation, but on a reduced set features. The original problem formulation is the task of supervised classification when the object class is determined by an expert. The object attributes values vary depending on its state, which makes it belong to one or another class, that is, statistics has an offset in class. Without breaking the generality, for carrying out simulation modeling, a two-alternative formulation of the supervised classification task was used. Data from the field of medical diagnostics of the disease severity were used to generate training samples.
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Applying software-mathematical models of onboard equipment to develop onboard software
Статья научная
This paper deals with the testing of the functioning logic of spacecraft subsystems at the stage of developing system onboard software. The increasing complexity of the structure and operation logic of spacecraft due to the increased requirements in terms of providing consumers with information services (navigation, satellite monitoring of transport, geodesy, communications etc.) demands maintaining the reliability of uninterrupted operation, the implementation of automated parrying of emergency situations during the operation of spacecraft onboard equipment. In order to meet these requirements, it is necessary to test the interaction of onboard equipment and onboard integrated computing complex software that implements the target-oriented operation of spacecraft onboard systems. In such a case, meeting the requirements for reliability increase of onboard software should not lead to the increase of the manufacturing period of spacecraft. In this work we propose the approach for testing information and logical interaction between onboard equipment and software of a spacecraft onboard integrated computing complex with the use of a laboratory testing sample unit and a software-mathematical model. We described the basic concepts of conducting two-stage testing of onboard soft-ware, involving autonomous and system testing on the ground testing complex. The proposed approach is applied as part of the onboard software development cycle in accordance with the standards of the JSC “Academician M.F. Reshetnev “Information Satellite Systems”. The approach proposed in this work helps reduce the number of errors during onboard software development and testing of information and logical interaction between onboard equipment and a spacecraft as a whole in every operation mode.
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