Статьи журнала - Сибирский аэрокосмический журнал
Все статьи: 3183
Self-configuring evolutionary algorithms for travelling salesman problem
Статья
This paper considers genetic algorithm (GA) and ant colony optimization algorithm (ACO) with the automated choice of operators for the travelling salesman problem solving. The choice is based on operator probabilistic rates calculated during algorithm execution. The performance comparison with other heuristics such as Lin-Kernigan heuristic (3-opt) and Intelligent Water Drops algorithm (IWDs) is fulfilled and competitive results are demonstrated.
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Self-configuring genetic programming algorithm for medical diagnostic problems
Статья
Genetic programming algorithm for neural network automatic design is suggested. Ensemble member competence estimations based procedure of decision making with intelligent information technologies is proposed. Effectiveness of the approach is proved on the benchmark and real-world medical diagnostic problems.
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Self-configuring multi-strategy genetic algorithm for non-stationary environments
Статья научная
Many real-world problems of design and control in a field of the aerospace lead to optimization problems. Such optimization problems are complicated and become a great challenge to many optimization techniques. Moreover, many real-world optimization problems are dynamic and changing over time. Changes occur in the parameters, objectives and/or problem constraints. In this case, search algorithms should have the capability to track moving optima and adapt to a new environment. In past years many approaches for non-stationary optimization were proposed. The best results are achieved using a stochastic population-based search such as evolutionary and genetic algorithms. Unfortunately, real-world non-stationary optimization problems include various types of changes and are poorly predictable, thus there is a problem of choosing a proper optimization technique and tuning its parameters. This study presents a novel approach for designing a multi-strategy genetic algorithm based on a hybrid of the island model, cooperative and competitive coevolution schemes. The approach controls interactions of different genetic algorithms and leads to the self-configuring solving of problems with a priori unknown structure. A short survey on non-stationary optimization problem and methods is presented. The results of numerical experiments for benchmark problems from the CEC competition are discussed. The proposed approach has demonstrated efficiency comparable with other well-studied techniques for non-stationary optimization. And it has significant advantage - it does not require the participation of the human-expert, because it operates in an automated, self-configuring way.
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SibCube - проект студенческого космического аппарата СибГАУ класса CubeSat
Статья научная
Описывается студенческий проект сверхмалого космического аппарата SibCube. Определены цели (описаны образовательные и научные цели) и задачи проекта SibCube, проведен анализ физических условий и технических проблем, связанных с ресурсными ограничениями такого класса космических аппаратов. Определены направления исследований и пути решения данных проблем, а именно, тестирование новой элементной базы и технологий, в частности, бортового комплекса управления, выполненного по технологии «система-на-кристалле», и оборудования, поддерживающего телекоммуникационный стандарт Space Wire. Отработка использования новых технологий актуальна в связи с консервативностью космической промышленности. Также в Российской Федерации отмечается ограниченность отечественной элементарной базы. В наше время все чаще говорят о импортозамещении. Для такой огромной отрасли Российской Федерации, как спутникостроение и космическая область, в целом необходимость в своей собственной элементной базе очевидна. Однако необходимо также и тестирование такой базы. Разработчики космических аппаратов предпочитают использовать проверенную элементную базу, опасаясь недостаточной надежности непроверенных элементов. Представлена концепция модульной масштабируемой служебной платформы SibCube и описаны методы достижения модульности и масштабируемости, используемые на конструктивном и системотехническом уровнях.
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Статья научная
Electrical design of on-board radio-electronic equipment is an important stage in spacecraft design. High charac- teristics of printed circuit boards (PCBs) are essential for miniature units that have reliability, speed, stability of elec- trophysical parameters, electromagnetic compatibility. In order to do that, new design and technological solutions are necessary, in particular transmission lines with stable characteristics of per-unit-length delay (τ) and wave impedance (Z). One of the main lines, realized on a PCB is a microstrip line (MSL). In multi-layer PCBs it is often used with poly- gons. However, their influence on the stability of characteristics is investigated insufficiently. The purpose of the work is to investigate the dependence of τ and Z of MSL on the distance between the side grounded conductors as they are dipped in a substrate. In the TALGAT software we built a geometric model of the line cross-section and calculated (using the method of moments) the matrices (3*3) of per-unit-length coefficients of electrostatic induction taking into account the dielectric as well as ignoring it. We calculated the values for the change of distance between side conductors (s), dipped in a sub- strate, for different values of the height of the side conductors (h1). We revealed that for large values of s (unlike small ones), approaching of the side conductors to the air-substrate boundary does not increase but it decreases the value of τ. When s = 0.38 mm, the change of the value of h1 in the whole range almost doesn't change the values of τ and, therefore zero sensitivity of τ to changes of h1 is possible. Thus we can obtain the required Z value in the range from 48 to 59 Ohms by changing the value of h1. These results are obtained for particular values of the parameters of the line. However it is easy to obtain similar dependencies for other values of parameters. The results can be used to design transmission lines with stable delay un- der control of the impedance value.
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Signals transmission by invariant method with further non-linear processing under weak correlation
Статья научная
The invariant system of information processing based on square-law characterized non-linear processing has been synthesized. In calculating of the parameters of such system it is assumed that the readings of the sub-carrier are interfered with additive noise and weakly correlated with each other. The quantitative estimation of the operation of such system is compared with the quantitative indications of the classical system with amplitude modulation and with the characteristics of the invariant system on the basis of extended synchronous detection.
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Статья научная
The elements of construction of electric propulsion system of spacecraft (SC) correction can accumulate electro- static charge due to interaction with the magnetospheric plasma. The impact of electrostatic discharges on the electri- cal circuit of the correction system can lead to failures of the transformation and control system (TCS). Particular attention is currently being paid to solving the problems related to the impact of electrostatic discharges on electric circuits of the power conditioning units, designed for power supply and control electric propulsion thrusters of space craft correction. Due to the design of the propulsion subsystem thrusters it is impossible to solve the problem of electric charge impact on TCS electric circuits through shielding these circuits. Therefore the impact of electrostatic discharges on electric circuits from the propulsion subsystem thruster is considered to be one of the factors determining the reliability and failure-free operation of TCS and, consequently, of the overall spacecraft propulsion subsystem. This problem is important today due to the following: the widespread use of electric propulsion thrusters in GEO spacecraft correction systems, the implementation of new TCS design and technical solutions suitable for spacecraft unpressurized platforms, the implementation of new electronic component base. The paper addresses the simulation means of electrostatic discharges occurring on the ceramics of the stationary plasma thruster and impacting TCS electric circuits, in particular the test equipment for generating high-voltage pulses, which allows replacing long-term and expensive tests performed on vacuum test benches. The paper contains the review of validation test results for TCS means of protection from electrostatic charge effects using high-voltage pulse generat- ing (HVPG).
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Статья научная
The research work presents the results of computer simulation of mass loading influence represented by two metal layers on variations in the dispersion modes of the Lamb and SH elastic waves phase velocity in the piezoelectric lay- ered structures Me/ZnO/Me and Me/AlN/Me depending on the elastic wave frequency and the ratio of the metal layer thickness to the piezoelectric layer thickness. The studied materials of the piezoelectric layers have a set of such sig- nificant properties as large values of the electromechanical coupling coefficient for piezoelectrics and significant val- ues of phase velocities for bulk waves and surface acoustic waves. Aluminum (Al) and molybdenum (Mo) are consid- ered as metal layer materials, which are most often used in the manufacturing of acoustic electronic devices. For both types of structures it was revealed that only the Lamb elastic wave modes have localized maxima of S sensitivity. It was found that the value of changing in the elastic wave phase velocity depends on the ratio of the metal layer acoustic im- pedance and the piezoelectric plate material. The maximum sensitivity values of elastic wave modes are achieved with Al/AlN/Al configuration, i.e., in a system with low acoustic impedance values of the bulk longitudinal wave for the layer and piezoelectric plate materials. The results of the simulation can be used in the development of various acousto- electronic devices, including some components of the rocket and space technology electronic base.
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Simulation of the cost of residential property in Krasnoyarsk for 2013-2014
Статья научная
Data on the cost of secondary residential real estate in the city of Krasnoyarsk for the years 2013 and 2014 was collected and analysed. The number of objects in 2013-4031 items, in 2014-1037 items. Each flat is characterised by 13 parameters: number of rooms, layout, residential district, floor, total number of floors in the building, material of the walls, telephone, total useful floor area, living space, kitchen area, WC-and-bathroom unit, kitchen stove, availability of a balcony or stanza. On the basis of ordinary least squares (OLS) an adequate linear model of the cost of a flat for the years 2013 and 2014 was created. Their own significant factors were found for the models of each year. Also separate models for flats in Oktyabrsk and Sverdlovsk districts of the city of Krasnoyarsk for the year 2014 were created. It was examined how the influence of general factors on price formation changed. The number of rooms factor started to have a smaller effect on the price of residential real estate. The negative coefficient on this parameter increased by 1.5 times. Layout also started to have a smaller effect on the price. The negative coefficient increased by 2 times. Residential district: the negative coefficient on this parameter has become smaller which indicates that the location of the flat in the city has started to have a larger effect on the price. Total useful floor area: the effect of this factor did not change. Living space: a change in this factor’s coefficient turned out to be the most prominent because it increased by almost 5 times. From the analysis of models of the price of flats in Oktyabrks district one of important factors is availability of a balcony or stanza. For flats in Sverdlovsk district important factors are material of the walls of the building and availability of a telephone. These facts can be explained by the specific characteristics of these districts. When analysing residuals of the obtained linear models heteroscedasticity of the residuals can be seen; it was shown by Goldfeld-Kvant, White and Glazer tests. With the help of generalised least squares (GLS) on the basis of the linear model new models with homoscedastic residuals were created. The created models adequately describe experimental data.
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Статья научная
The exchange mechanism influence on the electrons ordering on eg orbitals in a chain and in a two-dimensional Heisenberg model with exchange anisotropy for a S = 1/2 spin is determined by a quantum Monte Carlo method. The existence regions of a long-range quasi-one- and two-dimensional antiferromagnetic order with the special exchange topology are determined. The plateau existence region in the field dependence of magnetization, as well as the wave vector of the magnetic structure modulation with Q = p/2 in the (magnetic field - exchange alternating) plane, is determined.
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Статья научная
This article presents an evaluation of the size, form and quantity of the particles of titanium aluminide TiAI3 in rod inoculating alloying composition, used in semi-continuous casting of ingots of aluminum and aluminum-based alloys.
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Social and economic policy of Krasnoyarsk territory as a region of innovative development
Статья научная
The paper presents the relevance of regional planning. It proves that the innovative way of regional economy devel- opment is the most effective at the present stage. Each region follows its own way of innovative development and each one has its own peculiar characteristics. Krasnoyarsk Territory is one of the regions of innovative development, which is proved by various researchers and independent research agencies classifying the regions of Russia on different grounds. Thus, the region with the focus on innovative economic development requires a special social and economic policy, consisting of two aspects - social and economic. Social policy should reproduce human capital as the main fac- tor in the social and economic development of the region. Human capital, in turn, is formed from three interconnected components: reproduction of human resources (demographic policy), their formation and focus vector (employment policy on the labor market) and development of human resources or transformation of human capital into human poten- tial (education policy). For each of the three specified directions, particular recommendations are given within the framework of innovative development. It is necessary, for instance, to introduce a number of benefits that enable moth- ers to combine their work (study) and their main female function to stimulate the demographic policy. Within the framework of the employment policy, it is proposed to strengthen vocational guidance work to help young people's choice in the labor market. The education system should be made more accessible to all segments of population in order to increase its efficiency and quality. As for creating economic basis for innovative development, various forms of business associations and consolidations, such as strategic scientific alliances, investment public-private partner- ships and technology platforms are proposed. Technological platforms can become an effective form of business for Krasnoyarsk Territory, since they will make it possible to use the scientific potential of large universities in the region. The place of small businesses and self-employment in the regional economy of innovative type is defined as an auxiliary infrastructure of large industrial associations in the region.
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Solar thermal propulsion systems with various high-temperature power sources
Статья научная
The paper provides an overview of space thermal propulsion (STP) systems using concentrated solar energy as the main source of power. The paper considers solar thermal rocket engines of various configurations including those with afterburning of hydrogen heated in the “concentrator - absorber” system (CAS) with various oxidizers. Together with hydrogen the oxidizers form high-energy fuel compositions with a high value of ratio of components mass flow-rates which allows reducing the dimension of the CAS. The extreme dependences of the engine thrust on the specific impulse are shown for various values of the hydrogen heating temperature and the oxidizer-to-fuel ratio. The coefficients of the regression dependencies for the efficiency of a two-stage absorber and an absorber with the maximum non-isothermal heating having the highest possible energy efficiency are presented. The algorithms for calculating the main design parameters of the STP system as a part of a spacecraft (SC) are given, taking into account the ballistic parameters of the multi-turn transfer trajectory with multiple active segments applied to the STP systems having an energy-efficient non-isothermal CAS. The engine configurations with thermal heat accumulation and possible afterburning of heated hydrogen are also considered. Thermal accumulation allows accumulating energy in the solar-absorber during passive movement in the illuminated portions of the transfer orbits regardless of the lighting conditions of the apsidal orbit portions where the engine is turned on. Suitable heat-accumulating phase transition materials (HAM) such as the eutectic alloy of boron and silicon as well as refractory beryllium oxide are selected for different phases of the interorbital transfer to the geostationary Earth orbit (GEO). The main characteristics of different configurations of the STP systems in the problem of placing a spacecraft (SC) into high-energy GEO orbits are shown. A model of the SC- STP system operation is given taking into account ballistic parameters and the possibility of accumulating thermal energy. It is shown that the oxidizer-to-fuel ratio in STP systems with thermal energy storage (TES) increases with the decrease of the interorbital transfer time. The STP configurations with a two-stage TES showing a large energy-mass efficiency at moderate values of the solar concentrator accuracy parameter are considered.
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Статья научная
An information processing invariant system based on a linear detector in conditions of inaccurate determination of thresholds is considered. Quantitative estimation of noise immunity of such a system with its further comparison with noise immunity of an ordinary binary system with non-coherent reception is carried out.
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Steam turbines with a low-boiling working agent
Статья научная
The subject of the article is the assembly of a steam-generator plant with a natural working agent. A method of calculation for steam turbines with a low-boiling working agent is offered, which accounts for the correlation between the adiabatic curve indication, pressure and temperature in the overheated vapor area.
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Stochastic network equilibrium search with applications in the gas transportation model of Russia
Статья научная
We suggest an equilibrium search methodology under uncertainty conditions using the example of gas transportation model of Russia. This model includes gas producers and consumers that are joined by the network. Two-stage approach to finding the network equilibrium is described in details. For the first stage we investigate the method of demand and supply functions forming for gas consumers and producers that let us to find the equilibrium price as well as production and consumption volumes of gas. On the second stage we formulate a problem of finding the optimal plan of gas transportation with the network constraints. Then we add to our model the case of demand uncertainty and state a problem of finding the stochastic equilibrium in the gas transportation model. Gas production volume and price which provide demand satisfaction with specified probability is determined in our model. Described method of finding the stochastic equilibrium is applied to the gas transportation model of Russia. Results of numerical calculations are also given in this paper.
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Stratification of territories of innovative development: theoretical approaches
Статья научная
The factors influencing development of regions are studied in the article. The author considers approaches to territories stratification by criteria of innovation, existing in the scientific literature.
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Stress analysis of solar array driver mechanism actuator of the spacecraft “Luna-Resurs-1”
Статья научная
The intrrest of spacefaring nations in the Moon has grown considerably in recent years. Russia, China, the European Space Agency, the USA and some other countries have the Lunar programs. The movement around the Moon has a number of the features caused by gravitational field of the Moon, mascons and the small period of rotation. Therefore these features need to be considerd at the design of both the space vehicle and its components. The electro- mechanical block of solar array drive mechanism (SADM) of the spacecraft “Luna-Resurs-1” for a remote research of the Moon is presented. It serves for rotation of solar batteries panels and provides orientation of the panels by active part to the Sun. The purpose of this work is the analysis of strength characteristics of the spacecraft electromechanical block of SADM in the research of the Moon. Stress analysis of the basic power elements of the design by method of final elements in the Static analysis application of a CATIA package is made. The results of the calculation confirm the lifting power of a load-carrying structure. The minimum margin of safety of the most loaded detail is equal to 1.91. The developed device considers all the features of the movement on an orbit of the Moon and can be used in the research spacecrafts when studying a terrain and structure of the Lunar surface.
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Статья научная
The S-box is the most important component of modern cryptographic algorithms which largely determines the quality of cryptographic transformation. The modern method of estimating the S-boxes quality employs their representation as component Boolean functions to which cryptographic quality criteria are applied. Such criteria include: nonlinearity, correlation immunity, an error propagation criterion, and a strict avalanche criterion. Nevertheless, it is obvious that a cryptanalyst is not constrained in the ways of representing the cipher components, in particular, using the functions of many-valued logic. The design features of modern cryptographic algorithms allow their representation in the form of 4-logic functions, which determines the need to research cryptographic properties of the S-boxes represented as component 4-functions. In the literature today there are methods for measuring the nonlinearity of 4-functions; nevertheless, there are no similar methods for researching the differential properties of 4-functions, in particular, involving their compliance with the strict avalanche criterion. In this paper the strict avalanche criterion is generalized to the case of 4-functions and the compliance of the S-boxes component 4-functions of the “Magma” cryptoalgorithm to the strict avalanche criterion has been researched. All balanced 4-functions of length N = 16 satisfying the strict avalanche criterion were synthesized using the restricted brute-force method. The basic properties of the constructed class of 4-functions are determined, and bijective S-boxes based on them are constructed. It has been established that S-boxes of length N = 16 satisfying the strict avalanche criterion, both in terms of component Boolean functions and in terms of 4-functions, also possess optimal nonlinear properties. This circumstance allows us to recommend S-boxes satisfying the strict avalanche criterion of component 4-functions for use in modern cryptographic algorithms.
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Structure, network protocols of the Internet of things for quality production control
Статья научная
The subject of research is the model and structure of the Internet of things (IoT) network for product quality control in industry and agriculture. The purpose of the article is to analyze communication protocols and structures of IoT networks. The method of analysis and structural design of IoT networks is applied. The field of application is automation of monitoring products of enterprises of the aerospace industry. The article provides an overview and analysis of existing IoT technology; it considers the protocols and composition of IoT networks, and provides variations in the structures of building such networks. 4 levels of IoT architecture are described, as well as the communication protocols are used. The directions of building the Internet of things network for product quality control are defined. A multi-agent model of such system is presented, for the implementation of which the structure of the IoT network is given. The structure of a multigent system (MAS) for monitoring product quality in industry and agriculture includes many agents, such as product quality agents, communication agents, database agents, agents for analyzing information received from sensor agents, and decision-making agents. This MAS implements functions to ensure the required class of product quality and it is based on building a local network of the Internet of things. The research proposes an algorithm for processing information in such an IoT network. Analyzers (sensors) product qualities will be periodically polled and their values will be recorded in the server database. The decision-making subsystem sends data on product quality compliance to the enterprise administrator on a mobile device. The server structure is implemented using cloud IoT platforms, for which a brief overview is provided. The one IoT network implementation is developed using LTE NB-IoT technology. This approach can be used in the aerospace industry for product quality control within automation 4.0.
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