2011. № 42

A method for determining transaction serialization order in a database management system (DBMS) with strong strict two-phase locking (SS2PL) concurrency control protocol is proposed. Possible applications of this method for global concurrency control in a Mobile Data Access System (MDAS), which is a distributed heterogeneous database system with client working in a mobile environment, are considered.

Keywords: DBMS, distributed heterogeneous database, mobile data access system, concurrency control protocol, transaction serializability, transaction serialization order, strong strict two-phase locking.

Mathematical expressions for comparison of the methods of direction finding of the emitting source by the measurement errors are obtained. Graphs of distribution of the measurement errors in the coordinate space relative to measuring instruments are presented.

Keywords: direction finding; differential-phase method; Doppler method; direction finding error; lines of equal errors; mean-square error

The main purpose of the work was determination heating in layers of the rubber multilayer beem of the type torsion from composite materials under cycle loading on base analytical formulas built on base of the Duamell-Neimans thermotension hypothesis, theory thermal conductivity in paper by V. Gaitvud and theories function dispersion under cycle loading constructive details in paper by V. Moskvitin. The work has analysis to influence heating on strength, stiffness and adhesive properties in layers beam different section which can get reason fatigue exfoliation.

Keywords: multilayer beam, composite material, layers of the rubber, heating, shear deformation, cycle loading, function dispersion, fatigue exfoliation.

The main purpose of the work was investigation of the behaviour to springy line at loading three-layer beam on base analytical formulas built on base of the theories bending multilayer beam in paper by V. Vasiliev, theories loading three-layer shell in papers by E. Grigolyuk and nonlinear finite element method for bending springy peg within the frameworks of nonlinear dynamic flexible pegs stated in papers by F. Shklyarchuk and T. Grishanina. It was revealled and given explanation appearance unusual types to springy line to springy line at loading beem with greatly differring layer stiffness.

Keywords: three-layer beam, stress-strain state, finite element, nonlinear strain model, unusual springy line weariness toughness, layer stiffness..

The qualitative behavior of a non-holonomic mechanical system fr om robotics is investigated in a vicinity of the sub-manifold wh ere the rank of the system of the constraint equation falls down. New method to study singularities of first integrals of non-holonomic systems which can be reduced to a system of two first order implicit differential equations in two unknown generalized coordinates

Keywords: First integrals; singularities; degeneration of non-holonomic constraints; Whitney umbrella.

The development of numerical statistical method in rarefied gas dynamics relates with the usage of statistical modeling Monte-Carlo method in the first place. It has been used for calculation collision integral in regular finite-different program for solving kinetic equations, solution of integral equation, direct statistical simulation. Currently, most general methods for solving problems in rarefied gas dynamics present direct statistical simulation method. In this case, it is impossible without handling kinetic equations. The present work views general approach to construct Monte-Carlo method.

Keywords: Monte-Carlo method, rarefied gas dynamics equation, kinetic equations, directs statistical simulation method

Some bays of elastic wings of large aspect ratio and blades of helicopter rotors are made as anisotropic shells in order to couple deformation of bending, transverse shear and torsion. When changing the bending moments in this case it is possible to change correspondingly the twisting angles of the cross sections and so to control by distribution of the aerodynamic load along the span. In this work using the theory of thin-walled beams we obtained approximate analytical solution for calculation of the stress state and determined the yielding and rigidity matrixes of a bay of an anisotropic cylindrical shell with arbitrary symmetric one-closed contour or the cross section for bending, transverse shear and torsion. The results of this solution for the yielding matrix coefficients of the shell bay are compared with the numerical solution by the finite element method.

Keywords: cylindrical shell; anisotropic shell; shell with the arbitrary cross section; thin-walled beam; bay method; yielding matrix; rigidity matrix.

Results of researches on the impact of the discharge chamber configuration hybrid plasma thruster on operation and characteristics to increase stability of specific parameters and characteristics in the models of different dimension types within the range of operating power of 100 w to 2.3 kw, including operating modes at high discharge voltage are presented.

Keywords: hall effect thruster; hybrid plasma thruster; discharge chamber; current oscillations.

The article deals with physical simulation of ventilation processes in hydraulic trays for imitating aircraft cabins. The article gives a survey of hydraulic trays design, the process of surveying ventilation airflow in an aircraft cabin, which allows comparing physical and mathematical simulation.

Keywords: temperature fields; air velocity fields; aircraft cabin.

The methodology and results of development of the numerical model describing dynamic state of objects externally attached to the wing are submitted. The aircraft impact with a landing strip due to emergency landing is considered. The problem of transitional interaction is solved using finite element method, on basis of which the model of an aircraft carrying externally attached objects is developed. Time dependences of displacements, velocities and accelerations for different points of the objects are obtained.

Keywords: impact; aircraft; emergency landing; dynamic state; freights; external attachment; damping; finite element model; normal modes decomposition.

The article suggests a method of defining design and hydrodynamic parameters of hydrostatic drive, occasionally operating in conditions of significant inertia and positional load. As a simulation case there has been chosen the process of gyroplane rotor starting, there have been defined main parameters of the drive. There has been obtained existence domain of hydrostatic drive project.

Keywords: gyroplane; pump; relief valve; hydromotor; return valve; delivery pressure; reservoir pressure; heat liberation.

The paper describes new approaches of moment of inertia shape formation of future technology seaplanes. Defined preferable zones of placing fuel and payload accordingly its mass. Rated regularities between the geometric characteristics of alternative variants of placing fuel in the wing and payload (water) in the fuselage and the moment of inertia parameters about axis OX of the seaplanes.

Keywords: moment of inertia; fuel tank layout; water tank layout, payload layout.

The paper describes new approaches of moment of inertia shape formation over axis OZ of future technology airplanes. Defined preferable zones of placing payload in a fuselage accordingly its mass. Rated regularities between the geometric characteristics of alternative variants of placing payload in the fuselage and the moment of inertia parameters over axis OZ of the whole aircraft.

Keywords: moment of inertia; payload; layout, fuselage.

Time variations of the refraction index of proton-exchanged guiding layers on lithium niobate (X cut), which reflect slow aging (stabilization) processes in waveguides, were studied by mode spectroscopy technique. Structural changes in channel proton-exchanged waveguides after long-term stabilization (3 years) were studied by wet chemical etching of proton-exchanged layers and 3D profilometry.

Keywords: optical waveguide, lithium niobate, proton, exchange, aging of proton-exchanged waveguides.

The paper develops a gradient continuum model of the mechanics of materials with applications to the materials with a high density of internal interfaces. Assess the effective properties of material, taking into account the internal structure and scale effects, is given. The proposed model is based on the representation intergranular phase of the medium in the form of additional phase. Also the special surface properties of grains are modeled, due to the introduction of the surface energy of deformations. The model takes into account both the presence of variable properties inside the grains, and scale effects associated with the grain size.

Keywords: Ceramic, effective properties, the interphase layer, cohesion, adhesion, the gradient model, the law of the Hall-Petch

It is considered a flight profile for manned mission to Mars using nuclear electric propulsion. Considered flight profile has long duration (1000…1100 days) and it requires relatively low spacecraft mass at low earth orbit (200 metric tons). It is carried out feasibility study of the flight profile. Performance index is required propellant mass. Here minimization of required propellant mass is equivalent to maximization of total dry mass of nuclear electric propulsion system. It is shown the considered flight profile requires nuclear electric propulsion system having specific mass less than 15 kg/kW while thrust efficiency is 0.75, relative tankage mass is 0.1, and manned orbital complex mass is 60 metric ton.

Keywords: spacecraft; Mars project, manned complex, electric propulsion system, nuclear power supply system

There are carried out analysis and optimization of low-thrust heliocentric trajectories of solar orbiter. There are analyzed and optimized both direct flight profile and flight profiles using multiply Earth and Venus gravity assists to decrease perihelion radius and consequence of Venus gravity assisted maneuvers separated by resonant orbits to increase inclination. It is analyzed the expediency of various orbital resonances using. It is demonstrated the feasibility of radiofrequency ion thrusters using to transfer into typical target heliocentric orbits.

Keywords: optimal heliocentric trajectory; electric propulsion; ion thruster; gravity assisted maneuver

The problem of protection of the construction of a recoverable space vehicle from intensive exposure joint convective and radiant thermal streams becomes actual by development of reusable space vehicles of new generation. The decision of this problem will demand statement scale theoretical and experimental researches directed on studying of process of interaction joint convective and radiant thermal streams with a surface of heat-protective coating of the spacecraft. Thus development of the new heat-protective materials possessing higher heat-protective properties at their minimal density (ρ ≤ 103 kg / m3) is required. In the given work results of reproduction of the convective-radiant heat exchange accompanying an entrance of space vehicles in atmospheres of planets with the second space velocity are resulted. Such researches are carried out on the faculty « Aerospace heating engineers » of the Moscow Aviation Institute (the State Technical University) at support of the Russian Federal Property Fund, the project №09-08-00169-a.

Keywords: the convective-radiant heat exchange, heat-protective coating, the atmosphere of planet, convective and radiant thermal streams, the problem of protection.

In the article the algorithm of a two-level optimization of space system parameters is considered. It includes the decision of two extremal problems, the organization of the directed adaptation and ensure the coordination of design decisions. The algorithm considers features of search of design decisions in design office by working out the perspective space systems.

Keywords: space system; uncertainty; design decision; multilevel process; two-level model; algoritm.

Usually in solving the problems of designing a space system (SS) the process of acceptance of design decisions has multilevel, hierarchical character and passes in conditions of considerable uncertainty of the initial information. In the article the statistical method of the coordinated two-level optimization of Earth remote sensing space system parameters in the presence of uncertainties is offered. The method is a typical part of multilevel process of developing management. Possibilities of the offered method and questions of an estimation accuracy of the solution at top level of developing management are considered. The method allows to determine the requirements to accuracy of model parameters and to carry out an effective refinement of the design decision.

Keywords: space system; Earth remote sensing; uncertainty; design decision; multilevel process; two-level model.

The paper suggests a functional diagram of the system of risk management of aviation-industrial complex (AIC), which specializes in the development of new models of aircraft, representing a multiloop system with feedback. Four interconnected circuit correspond to the four horizons of management: regulatory and strategic, strategic, tactical, operational. Risk management is constructed in such a way that each circuit has been implemented corresponding subgoal management achievement in the aggregate which is aimed at achieving the main goal - to increase enterprise value. The proposed scheme satisfies the basic management principles: continuity, focus, systematic, integrated approach. The technique of calculating the basic cost parameters of the company used to manage risk as targets of the strategic risk management.

Keywords: Risk; strategic risk management; risk management system of the enterprise; cost approach; the contours of the strategic risk management of aviation-industrial complex

The problem of finding the level of risk in the enterprise of aviation-industrial complex (AIC). To solve it, the authors proposed algorithm for forming fuzzy system, which is used to find the risk level on the grade on the basis of linguistic values of the probability of risk event, the probability of changes to the financial performance of the company after the risk event and the indicator of the relative changes in financial results. Examples are given to demonstrate the effectiveness of the system formed.

Keywords: Risk; the level of risk; fuzzy sets; fuzzy system; fuzzy inference; linguistic variables; fuzzification; defuzzification

In the article presents a methodical approach to formation of Scorecard personnel component of productive efficiency and innovation potential of companies, developers and manufacturers of new aircraft, components, on-board equipment, devices.

Keywords: aviation industry; production capacity; training

This arcticle dicribes the problem of high level of equipment depreciation in Russian air industry. Renovation of funds could be promoted using leasing and credit instruments. The article offers an estimation method that was developed to compare both ways and to make a decision which of them should be used. It takes into account cost factors and non-cost factors and provides combined application of leasing and credit instruments.

Keywords: obsolescence, renewal of equipment, credit, leasing, integration.

The problem of an adaptation of electronic education system for retraining the young experts at the enterprises of an aviation complex is considered. Using the statistical analysis of testing program results, algorithms of adaptation of an initial system content are constructed. The theory of statistical hypotheses is used in the work for the statistical analysis. Results of approbation of the offered system for a number of groups of experts are presented.

Keywords: electronic education system; statistical analysis; statistical hypothes; feedback of control; virtual teacher.

The control system of an autoclave is considered. Obtained the transfer functions for correcting links to reduce the influence of ambient temperature on temperature instability on internal thermocouples of regulator.

Keywords: Transfer function, correction, autoclave, matrix.