2009. № 36

The procedure and outcomes of development of a numerical model and data of computational researches of a dynamic state of a load-carrying structure of the helicopter are submitted at its abnormal collision with different obstructions at stages of take-off and landing approach. Impact of a helicopter’s structure with an obstruction reconstituting properties of the building or a ship deckhouse under the given requirements of the approach is considered. The problem about non-stationary interaction is solved with use of a finite element method on the basis of which models of a load-carrying structure and an obstruction are developed. Time dependences of displacements, velocities and accelerations in different points of a structure of the helicopter are obtained.

Keywords: impact; load-carrying structure; oscillations; damping; an elasto-plastic material; a method of a finite element; one-way communication; an emergency situation, dynamic state, vibration acceleration

Research of dependence of frequency of occurrence of fires from time, seasonal and other factors in the territories adjoining to rocket proving grounds is conducted. The initial data for research was the database on forest fires of the Russian federation, based on results of space monitoring.

Keywords: the cosmodrome; space monitoring; starts of rockets; forest fires; frequency of number of fires

A consistent use of the exterior differential forms in the electromagnetism shows that fields of electromagnetism are geometrical quantities of two different types: differential forms and contravariant (antisymmetric) tensor densities. These types are connected with each other by a specific operation, named the conjugation, which is a part of the Hodge operation. Field tubes and families of bisurfaces depict electromagnetic fields. The conjugation allows a many-fold differentiation of the fields and leads to field chains. The Helmholtz’s decomposition of a field is a decomposition into a closed part and a closed after conjugation part of the field. Chains of fields of electric and magnetic dipoles are considered in detail. Concept of boundary of a field is used widely. Laplacian is represented in terms of the conjugation, and its action on isolated chains is considered. A sufficient condition of harmonicity of a field is found.

Keywords: Differential forms, Helmholtz decomposition, Hodge operation, Laplacian

Green functions for first order differential equations are considered rather than for common second order equations (for Poisson equation, e.g.). It is shown that a delta function for first order equations gives a closed part of the function that is integrated with the delta function rather than the original function itself as is common. A solution for a first order differential equation is considered as generating. Formulae are presented which relate the generating operator and a boundary operator. The Helmgoltz decomposition is compared with the Poincare decomposition.

Keywords: delta functions; field boundary; Hodge operation; Helmgoltz decomposition

The spectral method [1-4] was developed for analysis and synthesis of nonstationary continuous, discrete, and continuous-discrete control systems. In the last decade, the wavelet transform is used widely in digital signal processing [5, 6, 7-9]. Wavelet transform is liked to Fourier transform, but it describes better the local features of functions in the spectral domain. A wavelet application for linear nonstationary control system analysis is discussed in [10, 11-12]. In [11] the discrete wavelets are constructed by continuous wavelet discretization. In [8] the construction algorithm of p-stage discrete orthonormalized wavelet basis on the segment   is suggested.
In this paper the construction algorithms for p-stage discrete orthonormalized and biorthonormalized wavelet basis are considered. Its realization in the MLSY_SM extension package [11, 12] for Mathcad is shown.

Keywords: Biorthogonal wavelet bases; p-stage wavelet basis; non-stationary automatic control systems; spectral form of the mathematical description; mathematical computer-oriented systems

The method of fractal compression of images by means of iterated functions system is observed in the article. The basic ways of image splitting on not-crossed range areas are considered – they are triangular partitioning with restrictions where the image contours are interpreted as borders, the quadro-tree, and the proposed expansion of quadro-tree subdividing. Comparison of the compressed images quality and compression degree is resulted.

Keywords: Fractal images compression; iterated function system; digital video compression; triangular breaking; quadro-tree subdividing

The tracing technologies of human sight direction (i.e. eye-tracking) are used in various systems of computer interfaces designing. The timeline of eye fixing and trajectory density allow to obtain the conclusions about what elements of considered object or of entire image attract the greatest attention. Also, this technology is potentially capable to answer the question what defects arising at compression of the video image with partial loss of quality are most appreciable. As a specific example of this concept, we develop the approach of eye-tracking system with use of easy-accessible video equipment that allows to expand area of that systems.

Keywords: Technologies of eye-tracking; digital video compression; interface; ergonomic; video equipment

The hierarchy system of galvanic industry security indexes presented in article [1] is being developed. The social and socioeconomic indexes of the third and second levels of the hierarchy system are discussed in detail. These indexes allow to connect social, ecological, economic and technologic aspects of galvanic industry and take into account different exposure pathways of the pollutants on the human health and environment.

Keywords: galvanic industry, human health risk, socioeconomic damage, social and ecological and economic index