The article study notion of the digital image contrast. Various quantitative estimates of the contrast of digital images are investigated. Comparative experimental studies of different contrast estimates were performed on two standard image databases. It is shown that the evaluation of contrast by calculating the arithmetic average or MSE values of a set of local estimates does not always coincide with the visual contrast assessment. Experimental results showed that the Weibull distribution shape parameter is a more accurate estimate of the set of local contrast estimates calculated by the BEGH, GORD, LOEN functions and correlates well with the visual contrast estimates.

The article explored some properties of a very popular feature of image structural similarity, called the SSIM index. According to https://scholar.google.com, the article [3], where it was first described, has made more than 20,800 citations during the last 14 years. This indicator is actively used by the scientific community in imaging research. It acquired the status of an unofficial international standard for assessing image quality in the presence of a template, often referred to as the image quality metric. This article debunks some of the myths that have arisen around this index. A theorem is proved which states that the SSIM index and any of its linear transformations are not metric functions. In many publications and in the Matlab application software package in the description of the SSIM function, it is said that the SSIM index is used to measure the image quality. However, this index, as well as any comparison function with a reference image (such as full-reference), in principle, cannot assess the quality of the analyzed images. They estimate only a certain degree of similarity between the template image and its distorted copy. The article also shows that the SSIM index cannot always correctly determine the similarity of images of the same scene, while the Pearson linear correlation coefficient makes it much faster and more accurate.

The structure of model which allows to spend an estimation of system functioning efficiency of radio monitoring system of short-wave radio communication adaptive systems in adverse conditions of influence of external jams is described.

The article discusses a mathematical model of wind, taking into account its stochastic component and wind of a steady direction, presents the results of a comparative analysis of the effect of wind parameters on the total wind velocity vector acting on unmanned aerial vehicles (UAV). The main non-line arities of the autopilot servo elements and their influence on the output signal are considered. The reaction of the contour of the UAV flight altitude stabilization to the wind is considered, taking into account the nonlinearity of the servo drive elements. Proved the need to take into account the wind in the synthesis of automatic control systems (ACS) and the contours of the angular stabilization of the drone at stages where the flight speed of the drone is less than 30 m / s.

The description of the method and algorithm for embedding a hidden message or a digital watermark into files of Microsoft Word electronic documents in .DOCX format based on two steganographic methods is given. A Microsoft Word electronic document in .DOCX format is used as a steganographic container. One of the methods uses the features of displaying a document by a word processor and the word processor allows the displacement of hidden characters, such as spaces, tabs and paragraphs, in the text relatively to the line of text. The second method uses the feature of the .DOCX format electronic text document that a document is an archive containing Open XML format files and media files, so specialized steganographic methods for XML files can be used for embedding a hidden message. In this case the quotes replacement method is used. The embedding of a hidden message by one of the methods is used for checking the integrity of the other message through the second method. Depending on the capacity of the steganographic container a method can be chosen to embed the message and

a method to control the integrity of the message. The algorithm of the inverse steganographic transformation for extracting a message and confirming the integrity of an electronic document is considered. The application is developed to perform the embedding of a hidden message in an electronic text document depending on the capacity of the container. The possibility of using of some steganographic methods is analyzed with the aim of forming a multi-key steganographic system intended for a digital watermarking of an electronic document Microsoft Word format .DOCX.

This work is aimed at finding possibilities for increasing the accuracy of measurements and interfering analog interfaces for remote measurements using resistive strain gauges by introducing a new structural scheme, which is shown on the Fig. 1. It shows us the Schematic of the electrical functional analog interface for remote measurement using multiplexer and resistive strain gauges, which contains a measuring chain, a transmitter, the input of which is connected to a DC source through an analog demultiplexer, and the outputs of the measuring chain through the analog multiplexer are connected to the measuring amplifier, and a two-channel analog-digital converter with simultaneous sampling. The measuring chain is made in the form of three resistive current dividers, where one divider is formed by a resistive strain gauge and adjusting resistor, and two others – exemplary resistors.

By introducing a new structural scheme, it will be possible to increase the accuracy of measurements and impedance of analog interfaces for remote measurements using resistive strain gauges. In this case, unlike the classical method of model measures, this method is distinguished by the «indistinguishability» of the measuring line, which makes it possible to compensate for a greater number of influential factors, in particular, the correlated noise of operational amplifiers and noise caused by the presence of the overall ground loop, the resistance of analogue switches and lines of communication.

At the Fig. 2 we can see the electric model of the measuring channel in the software Elektronic Workbench.

From the analysis of the simulation results it was found that the random additive component of the error would dominate. Since in the simulation of the only random component of the error there is a quantization error, the use of the differential method of measuring the output voltage will significantly improve the metrological characteristics.

In the Kanter’s and Kinsella’s works is proposes the use of two synchronized artificial neural networks (SANN) connected by opening communication channel to confidential formation of a common cryptographic key. At the same time, there are few questions of practical suitability of this technology for cryptographic applications. There are no recommendations on the choice of parameters of the used networks, ensuring acceptable speed and guaranteed confidentiality of the generated general secret.

In this regard, it is interesting to substantiate the rational values of the parameters of ANN from the point of view of cryptographic requirements and security analysis of the proposed method of formation of cryptographic keys.

The use of information technology and, in particular, learning management systems, increases the ability of both the teacher and the learner to achieve their goals in the educational process. Such systems provide educational content, help organize and monitor training, collect progress statistics, and can also take into account the individual characteristics of each user of the system. The purpose of this study is to determine the direction of development of modern learning systems and technologies for their implementation. The evolution of learning management systems, the transition to intelligent learning systems, the main stages of such systems were reviewed, the types of learning sequences were analyzed, the transformation

into adaptive learning systems was identified, and the scheme of the system and its mathematical model were presented. Expertise systems, the theory of fuzzy sets and fuzzy logic, cluster analysis, as well as genetic algorithms and artificial neural networks are defined as the mechanisms for implementing the learning systems. An artificial neural network in an adaptive learning system will allow you to create a unique training program that will build on existing knowledge and the level of perception of educational material by students. By formalizing the intellectual processes that both the teacher and the student carry out, it is possible to automate a certain part of the teacher’s functions, reduce the cost of manual labor, which will make it easier to monitor the learning process and also make the learning process more efficient.