Home – Home – Jornals – Avtometriya 2009 number 6

The hodograph of the normalized moment of the energetic spectrum of a gradient image is analyzed. It is shown that transformation of the matrix form of the hodograph equation to diagonal form gives analytical expressions for the invariant characteristics of the image description-the principal spectral moments of gradient images. In this case, rotation of the coordinate system until its axes coincide with the eigenvector directions reduces the hodograph equation to the canonical form. An analysis of the initial equations, in rotation, yields invariant characteristics of the singular points of the hodograph. Subsets of invariant description characteristics for gradient images of different orders constitute a hierarchical system of invariant description characteristics of the initial image.

A quasioptimal method of antenna array control in information systems is proposed based on optimizing the integral parameters of an array in controlling the complex current amplitudes in some of the array radiators. Numerical calculations were performed which confirmed the validity of the analytical estimates. An estimate was obtained for the choice of the arrangement of  uncontrolled elements of an antenna array that minimizes the decrease in the energy parameters of  the antenna array with the quasioptimal control.

An approach to particle system processing on a GPU is discussed. Balancing of CPU and GPU loads is described in detail. Original approaches aimed at reducing the data flow from the system memory to the video memory are proposed. A comparison between the proposed GPU-based approach and the classical CPU-based particle system animation is given.

This paper considers an algorithm for the synthesis of an optimal filter providing a state vector estimator for a discrete linear dynamic system with additive perturbations containing an unknown constant component. The algorithm does not use perturbation estimators. Results of a computation experiment are given.

Ontology-based information systems for supporting research and commercial activities are considered. The tool kit required for supporting document analysis by automatic extraction of information of significance to the user from document texts is substantiated. These tools should support the various stages of text analysis and include workbenchs for designing specialized dictionaries and knowledge bases. The proposed approach allows a semantic analysis of texts based on knowledge of the subject domain, document genre, and specific terminology used by experts in the subject.

Justification and experimental verification of the computer vision algorithm and the maximum likelihood method for automatic estimation of the time of animal immobility in the forced swimming test are given. The computer vision algorithm is based on studying the difference between the frames with the animal images. The immobility estimates obtained by the existing methods and on the basis of the proposed criterion are compared.

Signal processing in the COMPLEX automated measurement system designed for noncontact inspection of wheel pairs of freight trains is described. The chosen coordinate base and methods of signal filtration and reconstruction ensure high reliability of measurement results during commercial operation even under conditions of intense atmospheric interferences.

A distributed measuring system of the stress-strain state of a plate is developed and tested. Optical fiber is used as the recording element. It is fixed on the surface of the body being deformed so as to solve the problem with the minimum number of measurements. Theoretical calculations are confirmed by the results of full-scale experiments.

A one-dimensional inverse scattering problem for the Helmholtz wave equation is considered. The problem consists in reconstruction of the refractive index of transparent inhomogeneous media from a specified complex reflection spectrum. A method previously proposed by the authors for reconstruction of the Bragg gratings in the coupled mode approximation is used. Numerical simulations of the inverse scattering problem for the classical Rayleigh layer and for an exponentially smooth transitional layer are performed. The solutions obtained demonstrate the high efficiency of the proposed approach. The accuracy of refractive index reconstruction turns out to be essentially dependent on the degree of layer smoothness. The proposed approach can be applied in problems of the development of coated and interference optics, in synthesis of the Bragg gratings and multilayer optical mirrors, and in radiophysics and acoustics.

This paper gives a brief review of some studies of acoustooptic methods for measuring sound velocity in solids performed at the Department of Acoustoelectronics and Acoustooptics of the Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science.

Publications on theoretical and experimental studies of multiple-beam reflection interferometers with a "non-inverted" response function in reflection are reviewed. Their operation principles and optical properties are described. The analytical form of recording of the response functions of such interferometers and the method of choosing parameters for controlling the form of the response functions are considered. Results of calculations and experiments are presented.

Analytical formulas for calculating the reflection coefficient of a thin-film metal-dielectric structure at light incidence angles greater than the critical angle of total internal reflection were obtained using a conducting surface model for a thin absorbing layer. It is shown that an asymmetric interference pattern of the spectral dependence of the reflection coefficient has higher sensitivity to changes in the refractive index of the medium.

The present state of research in the area of low-power design methodologies and mechanisms of power dissipation in digital circuits are considered. The choice of the corresponding model of power estimation is demonstrated to exert a significant effect on quality, cost, and performance of designed digital circuits. An analysis of various power estimation techniques at different levels of abstraction for sequential and combinational circuit design is presented. Special attention is paid to power dissipation analysis of programmable logic devices.

Tidal variations of gravity Δg measured with an error smaller than 1 µGal = 1·10⁻⁸ m/s² during the Solar eclipses on July 31, 1981 and August 1, 2008 with the absolute laser ballistic gravimeters developed and fabricated by the authors are presented.

This paper considers a destructive method of testing the strength flip-chip assemblies (in particular, photodetectors) which consists of separating one microcircuit from another with heating (not below 383 K) after thermal cycling. The method can be used to test the adhesive properties of bonding bumps, for example indium ones, in flip-chip assemblies and determine the causes of debonding in photodetectors. Examples of the causes of failures of cooled photodetectors based on HgCdTe molecular beam epitaxy are discussed.