Vol 14, No 3 (2013)

The article considers the critical aspects of design of the computer-aided system of the enterprise information security expert assessment, along with comparative analysis of the possible system architecture, classification of the major areas of information security, which are handled by the system and describes the key features, subsystems and custom use cases of the system. It was revealed that the architecture of Web-based applications is optimal for the system being developed. The levels of information security assessed with the system, such as: physical, ICT, administrative procedural level are analyzed in the context of important information assets of a certain enterprise. The authors designed four main functions and six subsystems of the expert system.

The authors suggest an approach to the dynamic model of an object of automatic control system by identification of of the object function and analysis of its nonlinear characteristics with the following study of the numerical characteristics of the obtained random values. The applied software tools provide for automation of the tasks for research on the basis of reliable methods (of Gauss-Newton). As a result it is possible to assess the reliability extend of the used transfer function at the task of the functional approximation for nonlinear characteristics of the object and to obtain quantitative values of the indicator that displays static characteristic from the time series of the full duration.

This article provides for the task of construction of the antenna pointing system, which does not influence the orientation and stabilization of the spacecraft. The mathematical model of the antenna pointing system, that can simulate the dynamic processes occurring in it, is presented. The evaluation of possible disturbing moments is made on the basis of a mathematical model of the spacecraft antenna pointing system. Simulation results of the disturbing moment maximum amplitudes and their corresponding frequencies are defined. It is determined that the found value of the disturbing moments do not exceed the allowable values in the whole time domain. It is shown that the results can be used to estimate the dynamic processes on the spacecraft as a whole and to assess the accuracy of its orientation in space.

The problem of stability of Beck’s column is still relevant, as there are no any unambiguous experimental confirmations of the theoretically calculated value of the critical tangential load on the elastic column, where the load may be caused by the effect of the rocket engine, for example. This article presents the estimation of the influence of the thrust that is delayed toward the tangential position. The estimation has been derived using approximate analytical methods and proves the existence of the dynamic loss of stability even for the states that are stable in the Beck's model. The conditions of the loss of stability are clearly demonstrated. The found solutions extend the capabilities of analysis of the stability and overcritical behavior of the complex nonlinear systems. A new direction of analysis of the deviations from the Beck's model has been formulated.

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.

The rapidly developing radio-navigation system (RNS), in Russia, as well as abroad, becoming an integral part in the life of the state as a whole, as well as of any structural unit in it. As a result, the consumers of RNS increase the demand for quality of communication service, security, functionality in the cost of its purchase and use. The aim of this work is the study and the qualitative analysis of the effectiveness of use of radio navigation systems. The paper describes the main challenges of RNS, as well as possible solutions. A generalized block diagram of the basic communication performance of RNS (economic, technical, operational, functional) is presented. On the basis of the results of this paper the authors propose a method of research and evaluation of the radio navigation systems in combination with other navigation means.

Let B 0 (2,5, k) be the largest finite two generated Burnside group of the exponent 5 of the nilpotency class k and {α 1, α 2} be generators of this group. Earlier the author together with A.A. Kuznetsov obtained the growth functions of B 0(2,5, k) with respect to the generating set {α 1, α 1- 1α 2, α- 1} for k ≤ 5. In this work a computer algorithm that calculates the growth function and the Cayley diameter of the graph of a finite p-group, defined by the generating set А = {α 1, α 2}, is created. On the basis of the algorithm the growth functions of B 0(2,5, k) with respect to the generating set А for k ≤ 5 is obtained. The considered task, besides for substantial significance, has applications as well. For example, a network of processors for parallel computation can be regarded as an undirected graph in which the vertices are the processors, and two vertices are joined with the edge if there is a direct connection between the two processors represented. The design of a large network is more feasible if the number of connections is small, but computations become more efficient if the short paths connect any two vertices (that is, the diameter of the graph should be as small as possible). Of course, these two requirements tend to conflict with each other. At the group-theoretic language the diameter of the graph of a computing network is equal to the maximum length of minimal words of the group graph.

The article considers the problem of critical pressure load determination for rectangular sandwich plate with one free edge, two opposite gimbal-mounted edges and one cantilever edge. Gimbal-mounted edges of the plate are under linearly varying load. This problem is not analytically solved yet. In this work the variation equations of plate stability were solved via Kantorovich method and via generalized Galerkin method, with special beam functions as basic functions. The analytical formula for critical pressure load is obtained. Calculations of critical loads for several variants of plates were done using this formula and the results were verified via finite-element package. The verification shows that the analytical formula could be successfully used in engineering and design calculations with minimal computational cost and high accuracy.

In this review article the authors summarize the results of the research on the mechanics of deformable solids in the Siberian State Aerospace University from the year 2000 to 2013. All articles are divided into three groups: 1) analytical studies of equations of mechanics of solids; 2) the numerical methods of solution of mechanics of solids; 3) the experimental methods in mechanics of solids. The first group includes mainly the works devoted to the analytical solution of the equations of elasticity and plasticity. They used symmetries and conservation laws, which allow to build not only exact solutions of equations of elasticity and plasticity, but also to solve boundary value problems for the equations. The second group contains works devoted to theoretical basis of numerical calculations; there are modifications of known methods that are tailored to address specific problems arising in the modeling of structural elements, in particular, of spacecrafts. The third group includes works that are devoted to the experimental study of the materials used in the construction of elements of spacecrafts.

The authors analyze the static accuracy of two types of solar array simulators: based on voltage regulator with current functional feedback and based on current regulator with voltage functional feedback. Parameters and signals variations impact on the static error of simulators is considered as well. The authors suggested the methods of improving the simulator accuracy and give recommendations for optimal selection of solar array simulator structure to achieve minimal error. The impact of parameter variations of solar array simulator devices on the entire error is shown. Along with it the authors consider the devices which meet the exclusive demands for accuracy, such as functional generator and current sensor. The comparison between the impact of systematic error and random error on the solar array simulator accuracy is drawn as well.

The classic problem of torsion of a straight rod with the cross-section being limited to a convex contour, has been solved. It is assumed that the domain of plasticity covers the entire external boundary. The laws of conservation are used to solve the problem. The solution for a piecewise smooth boundary is found with quadrature. The programs developed allow to construct plastic and elastic ranges with any precision in the torsion rod. Testing based on the known solutions gave the coincidence of the results.

The task of this work is to reveal the information on the practical implementation of the developed process of automation of maintenance system and repair of automation in the power plant of Norilsk city. The practical result of the system activity is the optimization of business processes, maintenance and repair of heating automatics and measurements, in order to reduce the time for decision-making and improve their quality. The author specifies the requirements to the system, shows the solvable problems, describes in details the configuration of the system, the composition and interaction of subsystems, network devices, designed interface and the way to access the data. According to the results of the system functionality realization, the reader can see and appreciate its features, cost-effectiveness and possible areas for further development of the system.

The computational modeling of the hardening process with the account of the effect of submersion was carried out. The modeling was performed with the account of temperature dependence of the material characteristics and the convective heat transfer coefficient. For stability of the numerical solutions with high gradients it was used the relation between the time step, thermal diffusivity and the characteristic size of the grid. There were received the distributions of thermal _ fields and stresses in the workpiece in the process of submersion and cooling in hardening medium, distribution of the residual hardening stress and deformation after hardening. The influence of the submersion direction of work parts in hardening medium on mode and value of the residual stress was revealed. To proof the results of the computational modeling, the seria od the full-scale experiments was held. The experimental results appeared to be in good agreement with theoretical calculations.

Development and improvement of the On-Board Control System (OCS) test methods, implemented in satellites manufactured by ISS, is considered in this paper. The authors has analyzed the available bench facilities of OCS test and indicated the problem to investigate and verify the next generation of OCS that based on network organization of data change. In order to solve a problem mentioned above it is required to develop the methods of the processes parallel control, as well as the diagnostic control of any abnormal status which might appear in the computation unit of the On-board computation network. Object-oriented analysis, algorithm creation and analysis methods, UML simulation methods are used during this work. Based on the created algorithms the preliminary stage of the branched Space Wire network test is fulfilled. The developed test facility and methods are used for OCS test bench development for future satellite and may be used to check and verify Control systems based on branched networks of data change. Created conception and methods will be used as a basis to test the new generation OCS in ground conditions.

The article considers the major problems of the control unit organization for spacecraft automation equipment. The advantages of transition to the program of microprocessor control by automation for perspective space vehicles are stated. The methods and solutions of the known problems and algorithmic technology plans, as well as the systemic organization of the designed control systems are discussed. The authors propose an integrated approach to the system organization of the on-board control devices based on the application of single-chip microprocessor-based computer systems of high reliability with a dynamically reconfigurable architecture in the digital part, as the central control systems. An example of organization and implementation of a module for stepper motor control system for disclosure of the antenna to operating position is considered, along with the main advantages of the proposed approach on the example of its implementation.

The main problem to be solved during the development of high-precision GNSS equipment is the reduction of the positioning error. The article describes the experimental results for high-precision navigation equipment. The experiment identified the main sources of pseudorange measurement error. Modern processing methods of satellite signals allow to reduce the pseudorange measurement random error to a few centimeters. Such errors as the ionosphere and troposphere, ephemeris error, and the error of GNSS time support may be excluded from the consideration. Therefore, the main components of positioning error are multipath error and bias error in the analog paths of the receiving equipment. The methods of the multipath error reduction and calibration options for bias error of navigation equipment are examined.

The article dwells upon the actual issues of the analysis of the control subsystem of a satellite with the account of the antenna unit being of high overall dimensions. According to the results of the synthesis of the vehicle orientation control subsystem of a highly elliptical satellite there came the decision to mount the antenna unit fixed stiff on the satellite and the solar array sections to rotate around the satellite body. It is proposed to utilize electromechanical servo-units that have no hidden angular moment and jet engines as servo-units producing external moments. Two drives should be used to rotate the solar array sections around the satellite body. Electromagnetic devices should be used to unload the electromechanical servo-units. The orientation on the Sun and the Earth is implemented with help of electro-optical sensors.

The way of the adaptive management process of development of the high-precision antenna reflectors, made of polymer composites, is considered. The process proceeds in a successive order, at the each process step the process parameters are measured and controlled, experimental curves defining the relationship of monitored parameters with quality of the finished product, are refined. On the basis of the obtained data the process parameters of the following stages, providing for the finished product quality target value, are optimized.

New data about influence of ceramic nanoparticles additives on the hard metals WC-Co, WC-TiC-Co, TiC-Ni-Mo properties are obtained with the use of calculating and experimental methods. The final physical and mechanical properties of hard metals modified with nanoparticles depend on their microstructural parameters, proportion of volume ratios and size of carbide and ultrafne particles. Nanoparticles introduced into a binder decrease the thikness of the metal interlayer and therefore increase the strength of binder and composite as a whole. The reduction of the carbide grain average size was found out as well (owing to nanoparticles blocking influence on recrystallization). The test results display that the modification with nanoparticles enables to increase the main properties: service durability 1,3-4 times; wear resistance 1,6-2 times; fracture toughness 1,8-2 times; transverse rupture toughness at 25-50 %.

In the article we propose the mathematical models for stationary and dynamic processes of the technological furnaces as objects with distributed parameters. This mathematical model is based on the laws of conservation of energy, mass and impulse and includes differential equations in private derivatives. Computational investigation of the stationary modes of tubular furnaces is conducted. For this purpose the boundary-value problem is formulated for calculation of concentration of the combustible substance, density, speed, temperature of the flue gas and temperature of the heated raw materials going for separation to the rectificative column. The results of the calculation of the technological parameters are presented. The proposed method can be used at automation rectificative plant in petroleum-refining and petrochemical industry.

The metal products of machine-building profile manufactured of billets passed through the cycle of melting-crystallization and having microcrystalline structure, demonstrate higher physical-mechanical properties and exploitation characteristics in comparison with the metal products of macro crystalline structure. During the process of melting the refining structure additives are introduced into liquid metal using master alloys for the aim of the structure refinement. In particular, the similar master alloy is the rod aluminum-titanium master alloy containing titanium aluminide particles which are the crystallization centers. It is determined, that the rod heating in the process of its introducing into the liquid metal leads to enlargement of the titanium aluminide particles, that decreases the efficiency of structure refinement. Therefore, in every particular case, it is necessary to optimize the velocity of rod introducing into liquid metal.

Aluminium is one of the most promising materials for hydrogen storage with high volumetric density. Furthermore, the excellent kinetics of hydrogenation and dehydrogenation can be achieved with surface modification of some transition metals. The possibility of hydrogen usage at the Al 3Ti, Al 3Ni and Al 4Pd phases, which can be obtained by high-temperature synthesis, was investigated by density functional calculations.

The ellipsometric measurement features of the ferromagnetic samples under the influence of an external magnetic field are shown. The analytical expressions for the Fresnel coefficients are presented with regard to the magnetooptical parameter in the off-diagonal elements of the dielectric permittivity. The model of a homogeneous semi-infinite medium, one-layer model, and the multilayer model of the reflective optical systems in the presence of a magnetic field in the equatorial magneto-optical Kerr effect configuration are analyzed. These models permit to interpret the experimental data of the ellipsometric and magneto-ellipsometric studies of layered magnetic nanostructures. For the first time the relationship of the ellipsometric parameters Ψ and A with magneto-optical parameter Q is obtained, δΨ and SA corrections in the ellipsometric angles are evaluated due to the equatorial surface magnetooptical Kerr effect. As a result, it becomes possible to measure the magnetic characteristics of the layered nanostructures, such as the hysteresis loop and coercivity with the conventional ellipsometric apparatus.

Oxyfluoride CsZnMoO 3F 3 has been prepared with the solid state synthesis. It was found that crystal is isostructural to pyrochlore and its crystal structure was defined with the Rietveld method more exactly. Despite the fact that the main structural element in this compound is distorted polyhedron, the cubic phase has been realized. The stability of the cubic phase over the temperature range T = 110-293 K was proved by the heat capacity measurement. The EPR spectra were analyzed over the range of 77-295 K. The presence of defects was revealed. The comparison between compound under investigation and CsMnMoO 3F 3 was implemented. Just a tiny change of the thermal parameters and the cell parameters was registered.

The features of interaction of Russian space industry companies with consumers at international market are considered. The article is aimed to research of the features of making contacts and signing contracts at international market of space products. The purpose of the article is to identify the features of making contacts with foreign consumers of Russian space industry products, to study factors defying the selection of space products manufacturer and to study experience of one of the most successful companies of Russian space industry in communication with foreign clients. Methods of analysis of expert opinions are used. The result of the work is the list of factors defining the features of interaction of Russian space industry companies with consumers at international market that should be considered during organizing interaction with foreign clients. The list helps to increase effectiveness of international market activity.