Vol 19, No 3 (2021)

Communications make up the most important part of the city's infrastructure, and as «smart» technologies spread, transport becomes one of the areas of their most active application. The use of intelligent solutions in the development of the transport industry is aimed at reducing of the impact of the «human» factor and associated negative manifestations, reducing transaction costs for the economy, increasing manageability and optimizing traffic management, which gives a positive effect of creating a better infrastructure along with environmentally friendly and socially favorable urban environment. The article describes intelligent transport system within the context of the «smart» city concept. The main advantages and risks of introducing intelligent transport systems, the prospects for their further development, as well as examples of digital forms of interaction between the authorities and society on topical issues of urban governance were analyzed.

The article presents an iterative algorithm for contour superposition. The contours to be superposed are linked by a transformation that includes offsets, angle of rotation, and scale. The points of the contours to be machined do not have a one-to-one correspondence. We have developed the procedure to estimate superposition parameters. This procedure includes the offsets estimation in the Cartesian coordinate system, the rotate and scale estimation in the log-polar coordinate system. The low error in evaluation of parameters is provided by the iteration procedure. The offset rating is used for correction of the angle of rotation and scale, and vice versa. Numerical modeling was used to estimate the error of the superposition parameters depending on the noise power. The error of the developed algorithm is similar to the brute force algorithm but speed processing is faster. The algorithm can be used in real-time measuring systems.

In an earlier work, the possibility of using a combination of M-sequence fragments with varying initial phases for probing a fiber-optic path was considered. The proposed method makes it possible to record the reflectogram of a fiber-optic path with high accuracy, but when it is implemented, the required memory volume increases significantly and the amount of computations increases significantly, due to the need to carry out correlation processing of the backscatter signal from each fragment of the M-sequence separately, and after processing it is necessary to carry out the operation of summing all the obtained autocorrelation functions. In this paper, we consider the use of a circular memory register to reduce the amount of memory occupied by the reflectometer and the number of computational operations. It is proposed to record backscatter signals from each fragment of the M-sequence into one common circular register, and then perform correlation processing of the entire data array at a time using a reference signal in the form of a complete M-sequence.

At present, large repositories of data obtained by scanning handwritten texts have been accumulated. A significant part of them are presented by scanned printed documents, which contain handwritten signatures of officials. The images of texts obtained in the process of scanning are often subjected to computer analysis in connection with one or another need. Search for fragments of these images, containing preset word forms, for example, in philology when studying the frequency of use of certain words by the same author is of significant interest. You can also indicate cases of word search from the standpoint of ensuring the safety of socio-economic processes. An important example is the detection of falsification of signatures of officials, etc. A feature of the automatic search for identical word fragments in images of scanned documents is the ability to identify them using only one text sample (precedent), which requires the creation of a special machine learning technique. In the presented article a decisive procedure for classifying word fragments of images of scanned handwritten text as identical to a given precedent has been developed. It was proposed to use the projection of vectors onto the eigenvectors of subband matrices corresponding to nonzero eigenvalues as elements of the feature space. A method for the formation of total subband matrices is substantiated on the basis of the introduced concept of information subbands in the area of spatial frequencies. A training procedure based on one precedent is proposed. This procedure is based on the developed method for generating vectors, the totality of which simulates the training sample. An algorithm for processing images when searching for identical to a given fragment was formed.

Virtual private network (VPN) technology is currently the mainstay for the exchange of confidential information through Internet. The technologies used to protect traffic of such networks consume router resources and affect the processing speed. Use of routers to encrypt and decrypt data can affect the transfer rate of this data over such network, especially if such network carries not only VPN traffic, but also traffic of ordinary Internet users. This paper compares the impact of encryption and hashing algorithms on the process of transferring packets over two types of VPN connections: Client- to-Site and Site-to-Site connections. A study of the influence of encryption and hashing algorithms on the speed and performance of two VPN-connection technologies when loading a communication channel was carried out. This experiment was carried out on computer and physical models. The computer model of the network was created in the GNS3 network emulator, the physical model was assembled using the next generation routers with integrated services Cisco RV 340. The research results are presented in the form of graphs and diagrams.

A feature of the information exchange process in data transmission networks in a complex interference environment is its randomness. Traditionally, such processes are modeled on the basis of the apparatus of the theory of finite Markov chains. At the same time, the classical approach to determining the characteristics of the message delivery process does not allow taking into account real time. This disadvantage is eliminated using the dummy state method. In this paper, on the basis of a system analysis, we have revealed the regularities of constructing a matrix of transition probabilities of an absorbing finite Markov chain using the dummy state method when simulating the process of delivering message packets through data transmission networks with a point-to-point connection. Construction regularities made it possible to formulate the rules for the automated synthesis of this matrix. The use of the proposed rules for finding the probabilistic-temporal characteristics of information exchange between network nodes is considered.

The process of adaptation (adjustment) to external influences is the driving force of the development of any natural (biological) and technical (anthropogenic) system. An attempt to develop and subsequently implement such a system turns out to be, in fact, a search for a scheme that takes into account all or the most probable operation modes. However, in reality, the designer of such devices solves the problem of minimizing the cases of system blocking. In the course of work, a team of authors made a fairly successful attempt to create an adaptive decoder on the basis of a programmable logic integrated circuit. By adaptation, the authors mean the search for the optimal scheme according to the following criteria: correction and bandwidth, delay. As a proposed solution, a device configuration has been created that includes: Arikana serial decoder, Tala-Vardi and cyclic redundancy code decoder. FPGA Xilinx Artix-7 is used as a platform. Some of the most important benefits of Xilinx’s Artix-7 platform include 50 % less power consumption compared to competitors, support for DDR3 at 1066 Mbps, shipping with an annual license, and use of the 28nm process technology. The results obtained make it possible to assert that the created adaptive decoder based on polar codes is expedient to use in control channels (critical to delays and functioning in the absence of local stationarity) of high-speed and mobile communication systems.