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Various methods of adaptive space-time signal processing in a survey radar system with a digital antenna array and wideband sounding signals intensively influenced by active and passive interferences are considered. Approaches to simulation of interferences acting on radars and their suppression by adaptive signal processing are discussed. It is proposed to simulate signals and interferences and their processing after transformation to the complex envelope in the frequency domain.

The problem of segmentation of natural and anthropogenic objects from panchromatic satellite images of very high spatial resolution (< 1 m) using texture analysis is considered. The effectiveness of various statistical methods for extracting texture features is analyzed. Based on the results of numerical experiments represented in this paper, we have selected methods that make it possible to segment the main types of natural and anthropogenic objects, as well as various structures of the forest canopy, with high accuracy (> 95%). We proposed the TTSPCA method, which allows the joined use of the most informative features extracted by different statistical methods. The results of numerical experiments show that the method proposed has higher texture segmentation accuracy (> 99%) in comparison with the standard texture extraction methods considered in this paper.

We discuss the technology of data processing for the AIRS hyperspectral suite and AMSU-A microwave sounder installed on board the Aqua satellite. This technology makes it possible to retrieve geophysical parameters of the Earth’s atmosphere and surface even with 80 % coverage of an observation area by clouds. The failure of the AMSU-A sounder in 2016 led to exclusion of its readings from the AIRS data processing scheme and to implementation of the simplified AIRS Only algorithm used today by NASA. In this paper we propose an approach to repair the AIRS «all-weather mode» using data from the ATMS scanning microwave radiometer on board the Suomi-NPP and NOAA-20 satellites. It is shown that the inclusion of the ATMS readings in the data processing algorithm makes it possible to obtain geophysical results that practically coincide with the original AIRS/AMSU data.

A method for estimating the nonlinear functional of the probability density of a three-dimensional random variable is proposed. It is relevant in the implementation of procedures for fast bandwidths selection in the problem of optimizing kernel estimates of the probability density. Solving this problem can significantly improve the computational efficiency of nonparametric decision rules. The proposed approach is based on the analysis of the formula for the optimal bandwidths of the kernel probability density estimate. The bandwidths of the kernel functions are represented as the product of an undefined parameter and the standard deviations of the analyzed random variables. The main component of the undefined parameter is a nonlinear functional of the probability density. The considered functional for a family of unimodal distribution laws is determined by the form of the probability density and does not depend on the density parameters. It is determined by the approximation of the functional dependence on the antikurtosis and skewness coefficients, which are estimated from the initial statistical data. To simplify the problem of restoring the desired dependence, the antikurtosis and skewness coefficients are transformed into a generalized parameter. The initial information is made up of a family of lognormal distribution laws. The errors of approximation of the considered nonlinear functional of the probability density are estimated by the values of the introduced generalized parameter for a family of three-dimensional lognormal distribution laws of independent random variables. The possibility of using the proposed methodology for estimating nonlinear functionals of the probability densities that differ from lognormal distribution laws is investigated. The influence of the arising approximation errors on the mean square criteria for recovering a nonparametric probability density estimate of a three-dimensional random variable is analyzed.

The features of carrying out X-ray lithography by synchrotron radiation (SI) using masks on thin (up to 50 microns) and thick (up to 1 mm) layers of X-ray resists are described with an illustration on specific examples of X-ray lithography stations of the VEPP-3 storage ring. The calculated graphs of the spectral dependence of the resolution of X-ray lithography on the size of the gap between the working surfaces of the X-ray mask and the substrate being processed, graphs of the dependences of the SI beam intensity and the absorbed power density on the depth of radiation penetration into the resist, and similar graphs for the contrast of the X-ray mask are presented. A description of self-supporting perforated (with through holes) metal X-ray masks is given. Reaching a new qualitative level of their production by laser cutting with a femtosecond pulse duration is illustrated by SEM photos, which will allow obtaining samples of planar elements of terahertz optics in the form of metal microstructures formed by means of the LIGA technology, varying the cell sizes, the width of “the line” of structures, and their thickness in a significantly wider range than was done earlier.

The optimal design of a cooled flip-chip photodetector in the infrared spectral range for installation in a cryostat is determined both with the possibility of bending during cooling and with rigid attachment to a pedestal through a sapphire plate. A numerical calculation is carried out for a radially symmetric photodetector model: GaAs (first layer) - Indium (ring structures) - Si - GaAs (second layer) with a plate diameter of 10 mm. The maximum deformation loads in the edge indium ring are determined for plates of different thicknesses (from 0 to 700 μm), which occur when the photodetector is cooled to 77 K. For the photodetector model, when it is fixed on a cooled cryostat pedestal with the possibility of bending, the optimal design is determined - GaAs(1) and Si plates with a thickness of about 50 μm and without GaAs(2;, the maximum deformation loads in the edge indium ring (width 15 μm, thickness 5 µm) with this configuration are approximately 427 MPa. When the model is rigidly mounted on the pedestal of the cryostat, the optimal design is GaAs(1) and Si plates 50 µm thick and a GaAs(2) compensation layer 100 µm thick; the maximum deformation loads in the edge indium ring under these conditions are 600 MPa.

A viscous liquid flow along a semi-infinite plate with small periodic irregularities on the surface was considered for large Reynolds numbers. The flow near the plate is described by Prandtl equations with induced pressure which are non-classical PDE, because they contain a limiting term. The main goal is to construct a numerical algorithm for solving these equations with periodic boundary conditions. The results of numerical modeling of the flow are presented.

This paper is devoted to the substantiation of a multiplicative model of time series decomposition based on the axiomatic approach. In this model, the original time series is represented as a component-by-component product of the selected components. The components are described in the form of monomials. To determine the values of variable monomials, a function is minimized that measures deviations from the unit of all components of the product of the selected components from the values of the corresponding components of the original series. In the model under consideration, all the components of the original series and the selected components are positive numbers. Four requirements are formulated for methods of selecting components. It is proved that all these requirements are met if and only if the time series decomposition is performed by a multiplicative model. As an example, we consider a model for selecting trends and seasonal fluctuations from monthly series of efficient data.

Based on the previously developed kinetic model of the catalytic reaction of the synthesis of benzylalkyl ethers, two- and three-criteria optimization of the conditions was carried out. The problem of multicriteria optimization is formulated with the definition of variable parameters: reaction temperature, proportionality coefficient of the starting reagents, reaction time; optimality criteria: yield of a target and by-products; restrictions on variable parameters. The computational aspects of multicriteria optimization by a grid algorithm (sensing) are examined. The calculated front values (optimality criteria) and Pareto sets (variable parameters) determine the exhaustive values of the reaction conditions and allow the decision maker to choose the most optimal ones. This made it possible to give technological recommendations for the industrial implementation of the synthesis of a benzyl butyl ether in the presence of a metal complex catalyst with a maximum yield of target products and a minimum content of by-products.

In this paper, one construction of the original «Harten-Lax-van Leer» method using a piecewise-linear reconstruction of physical variables is described. The obtained numerical method makes possible to reproduce a low-dissipation solution at discontinuities. To verify the method, we used the classical problems with an analytical solution based on various configurations of shock waves, contact discontinuities, and rarefaction waves. On the Sod-like problem, the order of accuracy of the developed numerical method was studied, it was shown that the main suppression of the order of accuracy occurs when the rarefaction wave is reproduced. The numerical method was verified by means of a three-dimensional Sedov test of a point explosion, and on the problem of a supernova Ia type explosion with two symmetric ignition points, leading to the formation of a G1.9+0.3 like remnant.