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The paper proposes an approach based on the use of mathematical methods for modeling the behavior of the designed web application and user behavior. This approach allows an evaluation of the usability of this application. The paper discusses the models of user interfaces (UI), which are used to assess the convenience of site navigation. The possibility of using two classes of UI models is shown – structural-logical (ontological) and probabilistic. Models of the first class are used to assess the degree of comprehensibility of the proposed UI navigation on the search web resource in the accepted terms. For this, mathematically defined measures of similarity between the elements of the UI and their relationships and the elements of a hypothetical (but plausible) model of the user’s perception of the search area in a given subject area are used. In particular, the paper substantiates the possibility of using Jaccard and Levenshtein lexicographic distance metrics as such measures of similarity. Probabilistic models are based on Markov chains. With the help of these models, in the presence of reliable statistical data collected during the trial operation of a web application or its prototype, it is proposed to estimate the average number of user steps required to solve a specific problem of finding information about a subject area object. The paper provides some recommendations on the use of similarity measures to improve the usability of the UI of web applications. In addition, data on the technique for estimating the probabilities of transitions of Markov chains and semantic connections are presented. To clarify the features of the UI analysis models proposed in the article, the website of the RTU MIREA Admission Committee (https://priem.mirea.ru) is provided with a fairly simple organization that provides a search for information about admission and training at the University. The application of the approach described in the paper, along with traditional methods of testing the usability of UI, will increase the overall level of usability of applications, and thereby reduce the cost of identifying and correcting related errors.

The article explores the trinitarian systems used in the natural and technical sciences. Various types of trinitarian systems are considered. A systematic analysis of trinitarian systems was carried out. The article proves that the trinitarian system is the simplest complex system. The paper examines the relationship of trinitarian systems with the theory of categories. It is shown that the trinitarian system serves as the basis for categorical analysis. The paper proves that the trinitarian system is the simplest multigraph. The trinitarian system allows transforming spaces of different curvature into each other. The trinitarian system in linear systems defines a cyclicity, which can entail: development, degradation or bifurcation. Triangulation essentially develops a trinitarian approach and can be considered as the use of a trinitarian system to solve theoretical or technical problems in areas such as, for example, psychology, social sciences, politics, geometry, and ground surveying. The general conclusion is that the Trinitarian system is a universal instrument of cognition.

In this paper, the spectral dependences of the transverse Kerr effect (ТКЕ) are studied experimentally and theoretically. The results are obtained for deposited and annealed samples with a corresponding variation in the size of the granules. It was found that thermomagnetic annealing leads to an increase in the ТКЕ value in magnetic nanostructures, while the most noticeable changes in the effect value were observed in the range of medium and high concentrations of the magnetic component in the visible region of the spectrum. The expediency of using the effective medium approach for calculating magneto-optical effects in granular systems, taking into account the size distribution of granules within the lognormal distribution of granules, is shown. Based on this approach, the main features of the optical and magneto-optical properties of nanocomposites are explained by the example of (Co45Fe45Zr10)X(Al2O3)1–X. All calculations are performed in the Bruggemann approximation, which effectively describes the properties of nanostructures in the region of average concentrations. Size effects are clearly manifested in nanocomposites and have a significant impact on the optical and magneto-optical properties of nanocomposites, especially in the IR region of the spectrum, which is associated with intraband transitions. Taking into account the particle size distribution makes it possible to significantly improve the description of such promising inhomogeneous nanostructures. The solved problem is very important and relevant both from the fundamental point of view – the study of magneto-optical, optical and transport phenomena in nanocomposites – and from the point of view of the great possibilities of their application in modern electronics and nanoelectronics. Taking into account the size effects and the particle size dispersion makes it possible to find new promising functional materials and control their properties in a wide spectral range.

The paper presents an analytical review of the application of biometric recognition systems in relation to facial image identification technologies. The classification of biometric systems is presented. The trends of technological progress in the field of biometrics and facial recognition capabilities are considered. It is determined that in 2020 there is a trend of transition from the use of biometric recognition technologies in traditional state security systems to the sphere of commercial and user applications. The process of «linking» encryption keys and passwords with the biometric parameters of the data subject is described. It is proposed that a biometric feature and a biometrics parameter mean a certain value that has a physical meaning that characterizes the subject itself. The possibility of using circular neighborhood and bilinear interpolation of pixel intensity values in biometrics is also presented. This will make it possible to build a local binary template. In order to solve the problem of identification of persons, it is advisable to investigate the essence of biometric systems in the technologies of identification of persons, their types, identifying the shortcomings of each of them, on the basis of which to present the directions of elimination and search for the most reliable technologies. The essence of the use of biometric systems in the technologies of identification of persons is, for example, that the user can provide the bank or other counterparty with evidence that it is he who wants to use the services on his accounts. At the same time, the demand has increased for contactless biometric solutions. These technologies are implemented in order to conduct additional biometric verification of users. This allows to minimize possible fraud or violation of the internal rules of the service, for example, the transfer of accounts of some registered users to others.

The article discusses the features of the radiation of ultrafast point clusters of charged particles moving uniformly near a gyrotropic medium interface. It is shown that some types of electromagnetic radiation – transient and/or Cherenkov radiation – have the characteristics of superchiral fields. Therefore, they can be effectively used to study chiral structures (for example, to detect circular dichroism, the frequency characteristics of refractive indices), various materials, including biomaterials. Ultrafast (relativistic) particles can serve as a «tool» not only for studying the structure of various materials. They can also be used as «generators» of quasiparticles that determine the «dynamic» properties of the materials under study, as well as the features of their interaction with radiation of various nature and response to external influences. In this paper, some types of circularly polarized EM waves propagating in optically active (magnetoactive, naturally active, gyrotropic, and chiral) media are considered. Using the generalized reciprocity theorem for media characterized by the Hermitian permittivity tensor, we consider the transient and Cherenkov radiation excited by a uniformly moving bunch of charged particles when it crosses (or moves along) the interface of media, one of which is an optically active gyrotropic medium. It is shown that the superchiral electromagnetic fields of the transition and Cherenkov radiation of dipoles can serve as a source of chiral collective excitations in magnetoactive and naturally active media. The investigated mechanisms of interaction of electromagnetic radiation with chiral materials (structures and media) are one of the possible physical approaches to solving the problem of the chiral purity of the biosphere and to elucidate the factor of deracemization of the organic primeval environment. A new hypothesis is presented, suggesting that ultra-high-speed clumps of charged particles of cosmic origin can cause deracemization of the prebiosphere.

Testing of electronic devices is an integral part of the technological process of any manufacturer of such equipment. In this case, an electronic device is understood as an energy-intensive unit such as a mobile phone, data center or spacecraft. One of the key stages of testing is to identify the effect of electric fields on various electronic components of the device. This stage often requires making a mock-up of some part of an unfinished device in order to fix interference with special equipment. This requires time, financial and human resource costs. In order to reduce these costs in the modern world, the use of mathematical modeling tools for testing noise immunity and electromagnetic compatibility is becoming popular. In this paper, it is proposed to use an algorithm for visualizing electric fields in three-dimensional space and time. The algorithm is easily embedded into applications as a component of a mathematical modeling system. The work considered three ways of visualizing the electric field strength: starting from a simple setting of points in space, on the basis of which the electric field will be built, around the source of electric field radiation, to the use of algorithms that make it possible to arrange points equidistantly based on a given number of points in space for the formation of an electric field. The performance and visual implications of these methods were analyzed. The proposed methodology will be useful to the developer community as an embedded solution for point visualization of the electric field in any project in any algorithmic language with the ability to animate in time.

This paper is devoted to construction of reference walking trajectories for developing pedestrian navigation algorithms for smartphones. Such trajectories can be used both for verification of classical algorithms of navigation or for application of machine learning technics. Reconstruction of closed trajectories based on data from foot-mounted inertial measurement units (IMU) is investigated. The advantages of the approach are the use of inexpensive sensors and the simplicity of the presented method. We propose algorithms for reconstruction of smooth 2D pedestrian trajectories based on measurements from a single IMU as well as on combined measurements from two IMU’s. Introduced algorithms are based on application of modified Kalman filter with an assumption of IMU having zero velocity when foot contacts the ground. In case of two measurement units, it is additionally assumed that the positions of the sensors cannot differ significantly from each other. The algorithms were tested on trajectories lasting from 1 to 10 minutes, passing indoors on horizontal surfaces. Obtained results were compared with high precision trajectories acquired with GNSS RTK receivers. Additionally, the process of inter-device time synchronization is investigated and detailed description of the experiments and used equipment is given. The dataset used for verification of proposed algorithms is freely available at: http://gartseev.ru/projects/rtj2021.

The study of ultrafast laser interaction with graphene-like materials based on transition metal dichalcogenides attracts most scientific groups. It is connected with potential use of these materials in flexible optoelectronic devices of visible and THz range. In this paper the parameters of generation of terahertz field from the surface of bulk layered crystal and monolayer film of tungsten diselenide are analyzed. Generation of terahertz radiation from the surface of experimental samples was studied by the terahertz time-domain spectroscopy in reflection geometry. Bulk layered crystals of tungsten diselenide were grown by gas transport reactions. Monolayers of tungsten diselenide crystals were grown by chemical vapor deposition on a silicon substrate. The bandwidth of the generated terahertz radiation from the surface of the bulk layered tungsten diselenide crystal was ~ 3.5 THz. For tungsten diselenide monolayer the spectrum bandwidth of the generated THz radiation was ~ 2.5 THz. The peak amplitude of the generated terahertz field for both samples was at a frequency of ~ 1 THz. Research of the influence of the angle of rotation of a polarization plane of optical femtosecond pump on peak-to-peak amplitude of the generated terahertz field from the surface of investigated samples was carried out. Symmetry analysis of the azimuthal dependence of THz radiation made it possible to separate the mechanisms of THz radiation and evaluate their contribution. The analysis results confirm that the only possible contribution to the generation of terahertz radiation in a tungsten diselenide monolayer crystal is the second order nonlinear optical effect – optical rectification. One of the contributions to the generation of tungsten diselenide is a nonlinear-optical effect of the third order – surface optical rectification.

The paper shows the approach and the result of taking into account the mutual influence of on-board subsystems of a complex technical object along the DC power supply circuits. Technical objects are understood as a mobile, energy-intensive vehicle, such as an aircraft, a surface or submarine vessel, or a railway locomotive with strong magnetic fields. The aim of the work is to create a simple and intuitive tool for mathematical modeling of the magnetic field vector at an arbitrarily specified observation point. The task is being solved in order to improve the accuracy of magnetic measurements on board, in particular, in navigation problems. On-board DC networks are considered, to which the approach of mathematical modeling is applied. The disadvantages of commercial programs of a similar purpose are noted. The binding of the objects under consideration to the general coordinate system is described. An analytical algorithm for calculating the magnetic field vector from the on-board cable network with a pronounced 3D trajectory is shown. Examples of visualization of the simulation results are given. An algorithm for calculating the induction vector based on the Biot-Savard law is considered. The algorithm for the analytical solution of the problem is described in detail. A specific power cable of the on-board network is considered. The cable is given by a set of straight conductors with current. The ways of future improvement of the created product with the transition from one observation point to the field map in a given three-dimensional zone of arbitrary position, volume and orientation are outlined. The obtained result is considered as an element of the procedure for achieving electromagnetic compatibility of energy-intensive and highly sensitive subsystems of a modern complex technical object.

Semiconductor industry calls for emerging memory, demonstrating high speed (like SRAM or DRAM), nonvolatility (like Flash NAND), high endurance and density, good scalability, reduced energy consumption and reasonable cost. Ferroelectric memory FRAM has been considered as one of the emerging memory technologies for over 20 years. FRAM uses polarization switching that provides low power consumption, nonvolatility, high speed and endurance, robust data retention, and resistance to data corruption via electric, magnetic fields and radiation. Despite the advantages, market share held by FRAM manufacturers is insignificant due to scaling challenges. State-of-the-art FRAM manufacturing is studied in this paper. Ferroelectric capacitors and memory cells made by main commercial FRAM manufactures (Texas Instruments, Cypress Semiconductor, Fujitsu и Lapis Semiconductor) are explored. All memory cells are based on the lead zirconate titanate PZT capacitor with the thickness of about 70 nm and IrOx/Ir or Pt electrodes. The leading FRAM technology remains the 130 nm node CMOS process developed at Texas Instruments fabs. New approaches to further scaling and new devices based on ferroelectrics are reviewed, including binary ferroelectrics deposited by ALD techniques, piezoelectronic transistors, ferroelectric/2D-semiconductor transistor structures, and others. Whether FRAM technology will be able to resolve one of the main contradictions between a high-speed processor and a relatively slow nonvolatile memory depends on the success of the new technologies integration.

Current trends in the design of electronic systems is the use of embedded systems based on systems on a chip (System-on-Chip (SoC)) or (VLSI SoC). The paper discusses the design features of electronic systems on a chip using the SystemC design and verification language. For the joint design and simulation of digital systems hardware and software, seven modeling levels are presented and discussed: executable specification, disabled functional model, temporary functional model, transaction-level model, behavioral hardware model, accurate hardware model, register transfer model. The SystemC design methodology with functional verification is presented, which reduces development time.The architecture of the SystemC language and its main components are shown. The expansion of SystemC–AMS for analog and mixed analog-digital signals and its use cases in the design of electronic systems are considered. Computing models are discussed: temporary data stream (TDF), linear signal stream (LSF) and electric linear networks (ELN). The architecture of the SystemC–AMS language standard is shown and examples of its application are given. It is shown that the design languages SystemC and SystemC–AMS are widely used by leading developers of computer-aided design systems for electronic devices.

This article focuses on gender discourse genesis in the context of both a new feminist movement and the emergence of feminist linguistics. The process of feminist linguistic theory conversion into the feminist social and political practices has also been revealed in the paper. German universities committed to all-European academic cultural tradition differed greatly from other European educational institutions by the number of women in the academic community. The low women representation in German academic environment is due to the following several factors:- academic institutions do not compete with each other for future students;- professionalization of science, achievements in scientific researches have caused the high status of a scientist in the German society, as well as the prestige of the academic career;- the academic career has become attractive for social elites;- the university boom has led to a dramatic increase of the number of female students and the number of women in the academic staff as well.These have resulted in the re-evaluation of a woman’s place and role in the society including the language structures and reflected by the academic discourse practices and notably in the so called geschlechtsgerechte Sprache, i. e. “equity in languages” principles.

The paper analyzes the condition of additivity of the information and reference kiosk, which allows designing a static kiosk, which is essentially a set of pages organized in order to provide users with reliable information in various fields of knowledge and practice, with additive properties. The condition of additivity is analyzed based on the loading time of the pages of the informational kiosk is implemented on the basis of the concept of a simple website with narrow subject matter by adding the concept of a vertical portal, in connection with which introduced the concept of optimal page load time of the informational kiosk, since the main task of the informational kiosk is the display of the user requested page containing the content within a certain time interval, and a key component of the kiosk GUI. Information and reference kiosk, as a small subscriber system in terms of functionality and volume of content, containing information in text, audio or video format, aimed at providing reference information to the user and giving him a means of interaction, by providing all available system objects and functions implemented in the form of graphical components, is not an exception. The article also discusses the key concepts of the information and reference kiosk, such as additivity, ergodicity, and entropy.

A review of robotic systems was carried out. The paper analyzes applied hardware and software solutions and summarizes the most common block diagrams of control systems. The analysis of approaches to control systems scaling, the use of intelligent control, the achievement of fault tolerance, and the reduction of the weight and size of control system elements belonging to various classes of robotic systems were carried out. The goal of the review is finding common approaches used in various areas of robotics to build on their basis a uniform methodology for designing scalable intelligent control systems for robots with a given level of fault tolerance on a unified component base. This part is dedicated to service robotics. The following conclusions are made on the basis of the review results: the key technology in service robotics from the point of view of scalability is the Robot Operating System (ROS); service robotics is today the main springboard for testing intelligent algorithms for the tactical and strategic control levels that are integrated into a common system based on ROS; the problem of ensuring fault tolerance in the service robotics is practically neglected, with the exception of the issue of increasing reliability by changing behavioral algorithms; in a number of areas of service robotics, in which the reduction of mass and dimensions is especially important, the robot control systems are implemented on a single computing device, in other cases a multi-level architecture implemented on Linux-based embedded computers with ROS are used.

A review of robotic systems is presented. The paper analyzes applied hardware and software solutions and summarizes the most common block diagrams of control systems. The analysis of approaches to control systems scaling, the use of intelligent control, achieving fault tolerance, reducing the weight and size of control system elements belonging to various classes of robotic systems is carried out. The goal of the review is finding common approaches used in various areas of robotics to build on their basis a uniform methodology for designing scalable intelligent control systems for robots with a given level of fault tolerance on a unified component base. This part is dedicated to industrial robotics. The following conclusions are made: scaling in industrial robotics is achieved through the use of the modular control systems and unification of main components; multiple industrial robot interaction is organized using centralized global planning or the use of previously simulated control programs, eliminating possible collisions in working area; intellectual technologies in industrial robotics are used primarily at the strategic level of the control system which is usually non-real time, and in some cases even implemented as a remote cloud service; from the point of view of ensuring fault tolerance, the industrial robots developers are primarily focused on the early prediction of faults and the planned decommissioning of the robots, and are not on highly-avaliability in case of failures; industrial robotics does not impose serious requirements on the dimensions and weight of the control devices.

Design solutions of domestic VLSI were obtained as a result of the application of computeraided design tools of a foreign supplier (CAD Synopsys, Cadence Design Systems and Mentor Graphics), based on standard libraries of PDK elements (Project Design KIT) of factories and IC-modules also supplied mainly by foreign companies. As a rule, the developer does not have its own production facilities, using the services provided by foreign factories (fablesscompanies). Due to this fact, relevant are the studies aimed at the development of a complex of measures, excluding the possibility of unauthorized changes into IC, i.e. protection of projects against intentional hardware and technology violations made during the formation of the control information for handing it over to the production facility and/or in case of IC manufacture at the factory. This paper considers this task from the standpoint of the analysis of the methodology of design for testability (DFT), i.e., a complex of measures that provide obtaining solutions at the design stage. The solutions include the verification of the correct performance of the manufactured chip by means of external tests and/or self-testing procedures. It was proposed, inter alia: 1) to analyze the libraries of standard elements used in the project with full disclosure of their specifications; 2) to create nodes with the physical non-cloning function in the projects on the basis of the libraries of standard elements in models and analysis programs; 3) to analyze IP modules used in the project with the maximum disclosure of structure, methods and algorithms for providing test coverings; 4) to provide for the development in projects of special test kits and methods of their generation at the design stage of functions in order to detect malicious nodes and programs both within SoC cores and at the level of system buses; 5) to develop at the design stage and to apply during tests a technique of special hardware measurements of parameters of the manufactured circuits and analysis of their results, inter alia, according to measurements of delays in distribution of signals and/or buses current consumption.

The paper presents the results of studies of the operation of the inverting DC–DC converter with charge pump and LDO, which are part of the combined bipolar secondary power supply LM27762, at the near to maximum input voltage of 5.5 V and an output voltage of –4.9 V. The ripple voltages were measured at various load currents from 10 to 250 mA at the positive pole of the flying capacitor, at the output of the charge pump system and at the output of the microcircuit. It was shown for the first time on the basis of the obtained information that at low load currents up to about 107 mA the charge pump system operates in the burst mode, and at currents greater than 109 mA – in the charge pump mode with a constant frequency. The results do not confirm the information in the documentation on the microcircuit that, at themaximum input voltage of 5.5 V, the charge pump can enter the PWM mode in hot conditions. When working in burst mode, the presence of LDO in the LM27762 chip reduces the ripples of the negative voltage at the output. However, they significantly exceed the values given in the documentation on the chip. During switching to the constant–frequency mode, the level of negative voltage ripples at the output of the microcircuit decreases sharply, but it increases with further increase of the load current and exceeds the values given in the documentation.

A method has been developed for finding the shortest Hamiltonian path in an arbitrary graph based on the rank approach, which provides high efficiency and a significant reduction in the error in solving the problem of organizing the process of managing multiple transactions and queries when they are implemented in network databases. In many cases, existing solutions do not provide the necessary results in terms of access time and accuracy of the found solution. Using the developed method allows minimizing the idle time of computing devices, reducing the volume and time of data transfer from one device to another, increases overall scalability, minimizes data access time, etc. An important advantage of the proposed method is to reduce the number of elementary operations and the number of vectors being processed the queue of the operations of the request, which leads to a significant reduction in time to implement the procedures for the formation of echer di operations in the requests. Methods of graph theory were used in this paper. The effectiveness of the task solution was evaluated using a systems approach, system analysis and the theory of operations research. Processing of experimental data obtained during the work was carried out in accordance with the provisions of mathematical statistics.

This paper presents the results of a study on the irradiation of heterostructures based on gallium arsenide with neutrons and gamma rays. The horizontal channel of the IRT-2000 reactor with an energy of 2.65 MeV served as a source of neutrons. Two types of structures were considered: autoepitaxial (AES) and heteroepitaxial (HES). They were obtained by the MOC-hydride method under reduced pressure using gallium and aluminum organometallic compounds and arsine. The obtained results show that irradiation with neutrons and gamma-quanta just slightly changes the concentration of the charge carriers of the autoepitaxial structures and the density of the charge carriers of the heteroepitaxial structures. As for the mobility of charge carriers, some increase in their mobility is observed at the initial moment of irradiation. As the irradiation flux density increases, the mobility either stabilizes at a certain level or decreases. The increase in mobility after the first irradiation of the heterostructures indicates an increase in the lifetime of charge carriers, apparently due to a decrease in the concentration of recombination centers in the structures, most likely, the density of structural defects at the heteroboundaries. When irradiating with fast neutrons, a similar picture is observed. Initially, the mobility of charge carriers slightly increases as the concentration of charge carriers slightly changes. Then the characteristics stabilize. An increase in the uniformity of properties over the area of the structures is observed. It is assumed that this is due to the appearance of clusters of defects and impurities.

The magnetorefractive effect (MRE) is important and interesting from both fundamental and practical points of view. This effect consists in a change in the reflection coefficient or the passage of an electromagnetic wave from magnetized structures with magnetoresistance effects. It can be giant, tunnel and colossal magnetoresistance depending on the type of structure. MRE is most clearly manifested in the IR region of the spectrum and can reach tens of percent. It is possible to show its unambiguous dependence on the magnitude of the magnetoresistance. This article discusses the features of MRE in multilayer metal nanostructures with giant magnetoresistance. The MRE simulation is carried out using a model that relates this effect to magnetoresistance, as well as in the framework of the model taking into account spin-dependent scattering. The last model in earlier works allowed describing a number of experimental data well qualitatively and in some places quantitatively. In this paper, taking into account the frequency dependence of the resistance allowed us to improve the first model, which allowed us to obtain a good qualitative and quantitative description of the effect value – this is a fundamentally new result. The article highlighted the key opportunity for the application of magnetorefractive effect as a contactless method to study nanostructures, a method of nondestructive testing of all electronic components. A comparison with experimental data is also made. A good description is demonstrated in the framework of the two models considered, which can effectively describe the relationship between MRE and magnetoresistance.

The paper presents the main results of scientific and practical research in the field of special design reengineering and counterreengineering of radioelectronic devices. Methods and means of special design reengineering of functional modules of multilayer printed circuit boards and case microcircuits are presented. The basic process design for the reengineering of multilayer printed circuits of radioelectronic products is presented. The design is based on the physical principles of destructive and non-destructive decomposing test: mechanical processing and chemical etching, stereolaser structuring, IR imaging electrothermics and X-ray analysis. The article formulates positions and methodology of the circuit analysis of the basic architecture of electrical circuits and signal processes of radio electronic products by the configuration of the printed circuit, its electronic component base and their connected topologies. The article considers methods and techniques for the reengineering of radiotechnical circuits and signals enabling to reproduce the list of the electronic component base and the essential circuit technique, as well as to study the basic circuit characteristics of the appliance in four main modes: functional, in-circuit, peripheral and identification visualization. The methods and means of authentic performance of radioelectronic devices for a number of constructive and radiotechnical identifiers are considered. Technical methods and solutions for counterreengineering of radioelectronic devices have been developed.