Home – Home – Jornals – Advanced Search

A likelihood function is obtained for estimating parameters of weak optical signals during detecting by means of recording emission moments of each photoelectron. Likelihood equations are derived and solved by an example of optimal estimates of a Gaussian pulse. Expressions for compatible and incompatible estimates of all three unknown parameters of the pulse are obtained. Analytical expressions for the Kramer-Rao bounds determining the quality of the estimates obtained are also derived. The variances of compatible estimates of the signal amplitude are demonstrated to be three times those of incompatible estimates, while the variances of the estimates of all parameters are inversely proportional to the product of the signal amplitude and its duration.

Thin films obtained by centrifugation of blood serum of healthy people and people with viscera diseases are studied by methods of spectral ellipsometry and infrared spectroscopy. Physical properties of such films are found to depend on the bio-organic composition of blood serum, which, in turn, is determined by pathological processes proceeding in the human organism. It is of interest that spectral ellipsometry and infrared spectroscopy are suitable nondestructive express methods of screening, i.e., preliminary blood diagnostics for patients with viscera pathology. Ellipsometric data on specific features of formation of bio-organic coatings from blood serum of patients with diffuse pathology of liver, hyperlipidemia, and diabetes mellitus are validated by changes in the fine structure of infrared spectra.

Optoelectronic methods for controlling the appearance of nuclear reactor fuel pellets are considered. In the proposed methods, reflected images of pellet surfaces are taken by digital cameras, which provides high contrast of defective areas against the frame background. Image processing algorithms for identification of defective products are given. An experimental model of a system with a capacity of up to 10 pellets per second was designed. A database containing surface images of simulators and real pellets was designed to train the system. Results of real time processing of the obtained images show that the probability of detection of defective pellets is not less than 95%.

The behavior of an inverted pendulum hinged on the wheel axis is studied. An algorithm is proposed for solving both the problem of pendulum stabilization in a given position relative to the vertical and the problem of controlling the velocity of the platform on which the pendulum is located under conditions of energy dissipation. Recommendations on choosing control system parameters are given, and the time of transitional processes is estimated.

We solve the problem of minimizing the ravine non-differentiable function defining the quality of the pole location in the synthesis of automatic control systems with reduced-order controllers. The relationship between the objective functions of the location of the polynomial roots and their derivatives is studied. The possibility of conversion from the non-differentiable characteristic of the location of the polynomial roots to a smooth characteristic of its derivative.

In densely populated cities or indoor environments, limited accessibility to satellites and severe multipath effects significantly decrease the accuracy and reliability of satellite-based positioning systems. To meet the needs of "seamless navigation" in these challenging environments, an advanced terrestrial positioning system is under development. A new principle of mobile robot navigation capable of working in a complex unknown landscape (another planet or just on a cross-country terrain) is proposed. The optoelectrical method proposed has a good spatial domain resolution and immunity to multipath, as well as new optical means for "technical vision" realization. Two related problems are solved: creation of a technical vision system for recognition of images of an unfamiliar landscape and determination of the direction to the initial point of the movement trajectory of the mobile transport robot. Issues of principle design and also of functioning and interaction of system units and elements are described. A mathematical apparatus for processing digital information inside the system and for determining the distances and angle measurements in the system proposed is developed. Some important parameters are analytically determined: expected accuracy, functioning speed, range of action, power issues, etc.

The most essential constraints of conventional technologies of processing multispectral data of remote sensing of the Earth in solving the problem of searching for man-made objects are analyzed. Several methods using structural features of images of man-made objects are modeled and studied. The efficiency of approaches based on classification of fragments with the use of the Harris detectors is demonstrated.

A histogram-based clustering algorithm is proposed that takes into account features of the collection of image texture statistics. The algorithm allows the addition of the false clusters occurring on the boundaries of objects with different textures, thus significantly reducing their number. The clusters are analyzed by estimating their separability in the multidimensional vector space of features and the image context. The application of the algorithm to the automated recognition of types of land cover from aerial photographs of forest landscapes is considered. A comparison of cluster maps and schematic map of ground survey shows their good agreement.

An approach to choosing the composition of a multivariate nonlinear relationship based on pair functions is considered. The approach is based on an analysis of the elements of decomposition of a multiple variance ratio (MVR) into pair variance ratios (PVRs), variance-correlation ratios of coupling effects (VCRCE), and variance ratios of interaction effects (VRIE). It is shown that if such a decomposition contains only PVDR, an additive composition of pair nonlinear functions is recommended. In a decomposition dominated by VRIE, a multiplicative combination is proposed. In a mixed set of variance ratios, mixed combinations are preferred. VCRCE participate in the selection of dominant variables. The identity of the models is determined by MVR. An example illustrating the various combinations of multivariate relationships is given, and variance ratios are analyzed.

A method of using the function of rival similarity (FRiS function) to solve the problem of predicting variables measured on strong (quantitative) scales is proposed. The FRiS-Pro prediction algorithm and the experience of its use in solving problems of predicting a target attribute, measured on the absolute scale (customer demand) at the international competition Data Mining Cup 2009