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The paper presents an approach to the parametric convergence performance improvement applied to the direct adaptive multi-sinusoidal disturbance compensation problem. The proposed method improves the performance of the existing solutions and ensures the transient monotonicity. The Dynamic Regressor Extension and Mixing (DREM) procedure followed by the discrete gradient estimator is applied for disturbance parameters estimation. The paper proves the applicability of Kreisselmeier’s scheme as an extension of the algorithm in procedure dynamic regressor extension. A numerical simulation is presented to illustrate the improvement of the transient processes of estimating the parameters of an unmeasured perturbation using the DREM procedure. The work can be used in solving practical problems in the fields of processing and evaluating harmonic and multi-harmonic signals, e.g., to suppress vibrations in electromechanical systems.

This paper deals with an optimal control problem for a linear discrete system subject to unknown bounded disturbances, where the control goal is to steer the system with guarantees into a given terminal set while minimising the terminal cost function. We define an optimal control strategy which takes into account the state of the system at one future time instant and propose an efficient numerical method for its construction. The results of numerical experiments show an improvement in performance under the optimal control strategy in comparison to the optimal open-loop worst-case control while maintaining comparable computation times.

The paper focuses on new steganographic algorithm development. Proposed algorithm is stable to compression, including high rate compression, and based on singular vectors insensitive of image matrix blocks which corresponding to maximal singular values. Algorithm is polynomial of degree 2. The results of numerical experiments confirm the efficiency of the proposed algorithm. [ABSTRACT FROM AUTHOR]

he most important element concerning efficiency and safety of developing mineral deposits is the consideration of the main structural features of the rock massif. The paper considers methodological issues of the GPR sensing application to study the internal structure of rocks. GPR surveys have been performed on a working bench of the Zhelezny mine, Kovdorsky GOK. Initially, the sensing has been performed by longitudinal profiling of the rock mass in its natural state to the depth of 20 m in combination with a telemetric survey of rock fracturing in the borehole located on the profile. Then the borehole was completely flooded with water, and GPR sensing studies have being repeated after 15, 30 and 60 minutes simultaneously with the registration of a decrease in the water level in the borehole. The GPR study results have been analysed in order to identify the effect of rocks' water-saturation on the recorded electromagnetic characteristics, and to determine the relationship of structural disturbance of rocks and their dielectric constant before and after water-saturation. It has been revealed that rock water saturation is an indicator that allows for more contrasting detection of rock disturbance zones due to the relatively insignificant difference in dielectric constant in the undisturbed and disturbed dry rock massif. The rock disturbance in an open pit slope has been estimated by GPR sensing, using water-filled borehole for contrast of measurements. The assessment has shown that water-saturated, porous, permeable, fractured rocks have higher dielectric constant values than dry / monolithic, weakly fractured rocks that have lower dielectric values permeability. It has been established that due to the water-saturation of rocks changes in the values of dielectric constant increased twice, and amounted to 0.6 units, while before saturation these changes were only 0.3 units, i. e. were two times lower. In order to substantiate the assessment of rock disturbance by GPR sensing, a comparative analysis has been made of GPR data and void of rocks in the vicinity of the borehole calculated on the basis of the filtration coefficient. The analysis has shown that the dielectric constant increases with increasing voids in the rock and, accordingly, with increasing water-saturation

The paper considers the problem of robust control of an electric generator with unknown parameters under the effect of external bounded disturbances and the presence of high-frequency measurement noises. It is assumed that only the load angle is available for measurement, but not the rotor speed. The electric generator model is described by a system of third-order differential equations with algebraic coupling equations. The proposed approach based on the separation of the filtering and estimating properties of the control system is used to solve the problem. Unlike existing analogs this scheme gives the possibility to control independently the quality of filtering and the quality of output stabilization. Also it compensates parametric uncertainties and external disturbances with required accuracy that can be reduced by selecting algorithm parameters. The proposed algorithm is easy in implementation and selection of design parameters.