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The paper analyses the known available method to search for the author of the text in the natural language base of knowledge proposed by O. Khrulev in which the minimum distance between the frequency dictionaries of the presumed authors and the text under analysis is accepted as a criterion for the successful identification of the author. The patterns and drawbacks of the method are revealed.The paper suggested that since the distance value is based on the average values of this lexeme-usage in all papers of the author on the basis of which frequency dictionaries are created, such leaps will show up when the specific value of the lexeme-usage frequency stands in stark difference to the average one.To test this hypothesis, the paper determines a variation coefficient of each lexeme-usage frequency in the texts under analysis.The analysis of frequency dictionaries of Russian canonical writers conducted in the paper has shown that on average about 90% of the authors' frequency dictionaries contain lexemes whose frequencies of usage are inhomogeneous.The author of the paper suggested that the coefficient of variation shows increase in author's word-hoard, i.e. the larger the vocabulary size, the richer the speech, and, therefore, the less frequently the author uses the same lexemes.In the paper there is a hypothesis that it is wrong to reduce the analysed size of the authors' frequency dictionaries only by critical boundaries: it is necessary to analyse lexemes with a variation coefficient over 33%, which illustrate rich word-hoard.The paper also proposes to define only one specific critical boundary of 10 thousand lexemes, since the indefinite boundary of 5 - 10 thousand lexemes offered by O. Khrulev makes it difficult to identify the author of unknown text. In this case, the lexemes with a variation coefficient over 33% of the total vocabulary size of the studied authors beyond the critical boundary are subjected to analysis.To test this hypothesis, a numerical experiment was carried out. The main point of the experiment was to identify the authors of unknown texts based on the authors' frequency dictionaries. At the same time, there were no unknown texts in the data compilation of the frequency dictionaries. The identification was based on the calculation of distance from the unknown text to the authors' frequency dictionaries, i.e. according to O. Khrulev’ s technique. In calculation different critical boundaries were specified.A numerical experiment has shown that the method proposed in the paper increases the successful identification percent for the larger size texts (more than 5,000 word forms) by 12.5%, and for texts of small size (less than 5,000 word forms) by 15.2%.

Currently, issues on processing of large data volumes are of great importance. Initially, the Andrews plots have been proposed to show multidimensional statistics on the plane. But as the Andrews plots retain information on the average values of the represented values, distances, and dispersion, the distances between the plots linearly indicate distances between the data points, and it becomes possible to use the plots under consideration for the graphical representation of multi-dimensional data of various kinds. The paper analyses a diversity of various mathematical apparatus for Andrews plotting to visualize multi-dimensional data.The first section provides basic information about the Andrews plots, as well as about a test set of multidimensional data in Iris Fischer’s literature. Analysis of the Andrews plot properties shows that they provide a limitlessly many one-dimensional projections on the vectors and, furthermore, the plots, which are nearer to each other, correspond to nearly points. All this makes it possible to use the plots under consideration for multi-dimensional data representation. The paper considers the Andrews plot formation based on Fourier transform functions, and from the analysis results of plotting based on a set of the test, it draws a conclusion that in this way it is possible to provide clustering of multidimensional data.The second section of the work deals with research of different ways to modify the Andrews plots in order to improve the perception of the graphical representation of multidimensional data. Different variants of the Andrews plot projections on the coordinate planes and arbitrary subspaces are considered. In addition, the paper studies an effect of the Andrews plot scaling on the visual perception of multidimensional data.The paper’s third section describes Andrews plotting based on different polynomials, in particular, Chebyshev and Legendre polynomials. It is shown that the resulting image is well correlated with the original point diagram and the Andrews plots based on the Fourier transform. This allows us to draw a conclusion that the Andrews plots based on the polynomial functions can be used for multidimensional data analysis.The fourth section studies wavelets as a basis for Andrews plotting. It is noted that wavelets have some advantages as compared to the Fourier series. In many areas of the signal analysis a Fourier transform is used for measuring the frequency characteristics of the signal over the entire area. The wavelet transform, on the contrary, is used when it is necessary to measure frequency characteristics in time-localized clusters. Fourier and wavelet transforms are complementary. Fourier transform yields an average frequency with respect to time, and the wavelet transform provides the signal frequency values at any time interval. Based on wavelets Andrews plotting through a set of test data, has shown that it is possible to apply this approach to the graphical representation of multidimensional data.

The paper presents the results of research that is aimed to improve the reliability of transmission of telemetry information (TMI) through a communication channel with noise from the object of telemeasurements to the telemetry system for collecting and processing data. It considers the case where the quality of received information changes over time, due to movement of the object relative to the receiving station, or other factors that cause changes in the characteristics of noise in the channel, up to the total loss due to some temporary sites. To improve the reliability of transmission and ensure continuous communication with the object, it is proposed to use a multi-channel system to record the TMI. This system consists of several telemetry stations, which simultaneously register data stream transmitted from the telemetry object. The multichannel system generates a single stream of TMI for the user at the output. The stream comprises the most reliable pieces of information, being received at all inputs of the system.The paper investigates the task of constructing a multi-channel registration scheme for telemetry information (TMI) to provide a simultaneous reception of the telemeasurement data by multiple telemetry stations and to form a single TMI stream containing the most reliable pieces of received data on the basis of quality analysis of information being received.In a multichannel registering system of TMI there are three main factors affecting the quality of the output of a single stream of information: 1) quality of the method used for protecting against errors during transmission over the communication channel with noise; 2) efficiency of the synchronization process of telemetry frames in the received flow of information; 3) efficiency of the applied criteria to form a single output stream from multiple input streams coming from different stations in the discussed multichannel registering system of TMI.In the paper, in practical implementation of the multi-channel registering system of TMI, additional effect obtained from applying a method of error-correcting coding TMI correcting omissions and inversion bits [1], is applied, as well as the effect of applying the criteria for the choice of parameters of TMI frame synchronizer [2]. This article presents the necessary and effective criteria for constructing the single output stream of information and to assess the quality of the output stream in various realizations of the multi-channel registering system of TMI.The paper discusses two options for building a multi-channel recording system. The first variant of the system does not use additional methods of error-correcting coding during transmission. The second option for constructing a multi-channel system is based on the use of the developed combination of convolutional codes and low-density parity-check (LDPC) (error-correcting coding method presented in [1]).The paper presents selection criteria of the most significant pieces of TMI input streams and a comparative analysis of the effectiveness of the proposed implementations. It gives a comparative assessment of the effectiveness of the proposed methods for constructing a multichannel recording system of TMI according to the following parameters: 1) bit error rate in the output TMI frame; 2) the percentage of fully reconstructed output frames; 3) the gain defined as the ratio of bit error rate in output TMI output frame for the systems under comparison.

The article considers an automatic quadcopter routing task. The quadcopter is an unmanned aerial vehicle (UAV), which has four engines. Currently, such already widely used vehicles are controlled, mainly, from the operator’s control panel. A relevant task is to develop a quadcopter control system that enables an autonomous flight. The aim of this paper is to study the possibility for solving this problem using an algorithm of the stabilization and trajectory control.A mathematical model of the quadrocopter is the fairly complicated non-linear system, which can be obtained by using the Matlab Simulink and Universal Mechanism software systems simultaneously. Comparison of the simulation results in two software packages, i.e. Matlab wherein the nonlinear system of equations is modeled and UM wherein the flight path and other parameters are calculated according to transmitted forces and moments may prove correctness of the model used.Synthesis of controllers for the orientation and stabilization subsystem and trajectory control subsystem, is performed on traditional principles, in particular using the PID controllers and method based on Lyapunov functions known in the literature as "backstepping." The most appropriate controls are selected by comparing the simulation results. Responses to the stepped impacts and to tracking the given paths have been simulated. It has been found that the flight path of a quadcopter almost coincides with designated routing, changes of coordinates for the quadcopter mass center of two controllers under comparison are almost the same, but a deviation range of the angular position for the controller backstepping is much smaller than that of for the PID controller.

Working vocabulary of features include most informative features of objects to be recognized. The aim is to develop a method of forming a working vocabulary of features for recognition algorithms based on Fourier-descriptors of the object image contours.To solve this problem the paper offers to use the method of functional maximization that is the ratio of the distance between the classes to the spread of objects within each of the classes represented in the feature space, which is formed on the basis of Fourier-descriptors.To check the effectiveness of the proposed method to form a working vocabulary of features the numerical experiments have been carried out. The experiments used two databases of reference images consisting of 10 and 13 reference images. Test images obtained by rotating the reference images, by zooming, as well as by adding the noise using the normal law of distribution have been created from these images. The proposed by the author algorithm, which uses the Prewitt operator, threshold segmentation, and morphological processing has marked the contours of images. The original vocabulary of features derived from the Fourier-descriptors has dimension of 98. The vocabularies of working features having the dimensions, respectively, 3 and 4 have been formed on the basis of functional maximization for both reference images. In the course of numerical experiments the frequency of correct decisions to recognise the features of reference bases of images for the original and working vocabularies has been evaluated. It has been proved that the algorithm of recognition with the formed working vocabularies of features provides a great efficiency of automatic recognition of objects.There are known publications, which use a similar method to form a working vocabulary of features in algorithms of human recognition by the image. But there are no publications on choosing the vocabulary of features for recognition algorithms based on the analysis of the image contours that can be used in computer vision systems of automated production lines.