Vol 18, No 4 (2020)

This paper assesses the various generalized mathematical models of microwave chiral metamaterials based on various forms of material equations. The article concludes that it is necessary to describe a chiral metamaterial as a heterogeneous media, taking into account the dependence of the effective dielectric permittivity on the container permittivity and permittivity of a volumes with chiral inclusions. In this work, mathematical models of a chiral metamaterial are constructed based on the Maxwell Garnett and Bruggeman formulas, taking into account the properties of heterogeneity. As the investigated chiral metamaterial we chose a metastructure based on fine-wire curved gammadions with different numbers of loops. For this structure, the resonance frequencies of chiral inclusions in the form of multi-loop fine-wire curvilinear gammadions were determined. As an example, we solved the problem of reflection (transmission) of a plane electromagnetic wave with linear polarization from a planar layer of a chiral metamaterial based on a uniform matrix of multi-loop fine-wire curvilinear gammadions. In this work, the influence of the number of gammadion loops on the reflecting and transmitting properties of the chiral metamaterial is determined. The article analyzes the issues of using the Maxwell Garnett and Bruggeman formulas to take into account the heterogeneity of the chiral metamaterial and their influence on the results of calculating the reflection and transmission coefficients of the wave. It is proved in this work that a planar layer of a chiral metamaterial based on multi-loop fine-wire curvilinear gammadions allows concentrating the incident electromagnetic field in the plane of the metastructure.

This article discusses the problems that arise with different ways of connecting network virtual switches and using the OpenFlow mode. A technique for automated research of performance parameters of virtual switches with OpenFlow support is proposed. In the course of the study, modes were identified in which significant packet losses and delays of more than 100 ms occur. It was found that at different parts of the packet’s route, using Open vSwitch in OpenFlow mode inside virtual machines is not optimal, while for virtualization systems, the connection via Open vSwitch is more preferable than Linux Bridge. Exceeding the load beyond the identified limits entails the need to optimize Open vSwitch and install a DPDK module for low-latency switching or change the load balancing on such nodes.

The Internet and wireless communications have created new opportunities for the mass exchange of multimedia information. This has created new challenges in terms of the security and storage of the information transmitted through global and local networks. This article is devoted to the study of steganography methods of safety, in particular, those based on LSB concealment, in the spatial area of digital images. The classification of steganography methods has given based on the works of the last 5 years. The most popular and widespread image steganography methods have been investigated, describing their merits and challenges. The most commonly used terminology was identified and various methods of data concealment are presented. The visual and statistical steganalysis methods for computing the statistical difference between the input image and the stegoimage is also considered. The article may be useful to researchers in developing new, more effective steganography methods of information hiding.

The superposition of television signals is a topical issue that is considered in the computer vision systems when locating and recognizing objects, as well as to increase the image quality and decrease the volume of stored data. The article shows the algorithm of the homography superposition of television signals by RANSAC. The developed algorithm includes the following: interest point recognition, a point’s matching between input images by RANSAC and estimation of homography parameters. The optimal additional step is the superposition by the Lucas-Kanade method. This method allows us to estimate subpixel offset in the neighborhood area of interest point and decrease the error of superposition. The developed algorithm is intended to automate television signals superposition of computer vision systems, especially for the aviation equipment and security systems.

The pending issue in digital TV and radio broadcasting technology is the certification of DVB-T2 standard transmitters, which are in operation in 85 regions of Russia. One of the main requirements to network transmitters, which is necessary for certification, is the requirement of time-calibrated information signal delay in modulators of network transmitters. The lack of time delay calibration of information signal processing is the main reason for technical defect in digital broadcasting, caused by the synchronization failure in the network transmitters. The results of the main stages of theoretical research and practical experiments carried out by the author earlier, which allow to take them into account in the development of the project «Rules of application of terrestrial television transmitters» at the level of the Ministry of Communications of Russia, are considered. The Ministry was renamed in its abbreviated name by Government Resolution No. 1389 dated September 9, 2020, into the Ministry of digits of Russia. The proposed algorithm of television transmitters settings, the innovative method and the calibration device, implemented on programmable logic integrated circuits, allow for synchronous operation of networks at the dispersal of information signal delays not only in the modulators of transmitters, as well as in data transmission channels. Upgrading of transmitters according to the recommendations of the article consists in additional equipment of modulators with one universal component of domestic production and adjustment of single-frequency network according to the algorithm considered. High manufacturability of the proposed solution allows to certify DVB-T2 standard transmitters in the shortest possible time and to provide reliable, uninterrupted TV and radio broadcasting by upgrading transmitters in operation in 85 regions of Russia.

Spectrum sensing is the most important function for cognitive radio networks. Since the probabilities of detecting primary users by secondary users can deteriorate under the influence of noise, interference, Rayleigh fading, it is necessary to choose the most suitable network architecture to improve the characteristics in both the delivery channels and in the sounding channels. This article discusses the task of sensing a licensed frequency band in order to detect the primary user of a cognitive radio network with a two-tier network architecture, on the first, lowest tier, secondary users are concentrated in separate small parts of the network coverage area (clusters) located at considerable distances from the center of the fusion of local sounding results individual secondary users. These local results are relayed by the base stations of the clusters to the merger center.

Modern manufacturing enterprises operate on the basis of complex digital systems. The infrastructure of these systems consists of computer nodes. Computer nodes can work efficiently or inefficiently. The efficiency of computer nodes is reflected in the operation of the infrastructure and in the production enterprise itself. Therefore, it is necessary to manage computer nodes. Management of computer nodes based on modeling of queuing systems and nonparametric statistics is considered. The structures of tools for performing the adjustment of parameters of computer infrastructure nodes are proposed. The resulting tool structures can be used as the basis for making adjustments to the parameters of the infrastructure’s computer nodes. This adjustment with the participation of the decision maker will be made taking into account the modeling of queuing systems and the application of nonparametric statistics to the results. The adjustment of parameters will ensure effective support for digital technologies when requirements change at production facilities.

The article concerns the appearance of IT neologisms in English. The enrichment of language happens mainly through addition of new words, meanings, expressions and idioms. The development of vocabulary is directly proportional to the process of neologization. The authors provide a typology of neologisms in the IT industry. Given examples of computer technology neologisms have the main nominative function, as well as the stylistic one. In the course of this research the authors note the emerging trend of idiomatization of neologisms-terms due to the dynamic development of science. The analysis of computer technology neologisms and IT term-neologisms makes it possible to conclude that the lexical structure of modern English is updating regularly, thereby reflecting new trends in the word-formation system.