ISSN 2224-087X (Print)
ISSN 2224-0888 (Online)
Collected scientific papers
"Electronics and information technologies"
(In 1966-2010 published under the title "Electrical engineering")
(Certificate of State Registration ÊÂ ¹17618-6468ÏÐ from February 11, 2011)
|Issue 8, Pages: 3-17|
|Modern methods and means of information protection|
|Yu. Korchak, Yu. Furgala, L. Korchak|
|The paper gives an overview of steganographic and biometric methods and means of information protection, as well as passwords, their current state and perspectives. Particular attention is devoted to methods of creating passwords, requirements to their length and quality. Using the GRC password crack checker service, the analysis of the dependence of the password break time on its quality (length, type of characters used) is analyzed. It has been shown that for safe protection against unauthorized interference, the length of the password must be at least 12 characters, using upper and lower case letters, numbers and special characters. Several approaches to creating passwords are considered, including replacement codes, mnemonic method, Blums method. An analysis of trends in the development of computer steganography shows that in the near future interest in the development of its methods will only increase. One of the reasons for increasing interest in steganography is that a few of countries have adopted restrictions on the use of strong cryptography and the use of steganography solves this problem.The stages of use of steganography for information security are considered and a series of applied software tools for creating a steganographic message (S-Tools, Steganos, JSteg, Hide-in-Picture), and conducting steganalization (StegDetect, FTK Imager, Stegosuite, File Signature Header, Maresware Forensic Suite) are described. Today, the biometric methods of protecting information that are most likely to identify a person are rapidly developing. These information security methods are among the most promising and are already widely used today by such famous manufacturers of electronic and computer equipment as Sharp, CardMedia, Fujitsu, Apple, Biolink Technologies. The article describes modern technologies and devices that are already used to identify fingerprints of a person, which ensures reliable protection against unauthorized interference.|
|Issue 8, Pages: 18-25|
|Emergency landing of quadrocopter in the unmanned flight|
|B. Blahitko, Yu. Mochulsky|
|The necessity of analyzing and modeling process of the emergency landing unmanned quadrocopter is described. All articles, without exception, are devoted to problems of an unmanned flight of a quadcopter, unconditionally foresee that all four pairs of screw-engines and their control system function correctly. In practice, often there are those or other faults in the sequence of links: the control circuit - the motor-the screw. When a malfunction suddenly appears during the quadrocopter unmanned flight, then an emergency situation occurs. Through mathematical modeling the basic features of landing unmanned quadrocopter are considered. The results of mathematical modelling of quadrocopter landing after the appearance of failure of one of the four pairs of electric motor-screw are presented. When the quadrocopter landing after failure of nose pair or of tail pair the electric motor-screw, the quadrocopter begins a counter-clockwise rotate and falls to the ground. When the quadrocopter landing after failure of right pair or of left pair the electric motor-screw, the quadrocopter begins a clockwise rotate and falls to the ground also. The vertical speed at the moment landing is equal to the free fall practically. The horizontal speed at the moment landing, as well as the angle and the landing site are unpredictable, The methods of safe landing of an unmanned quadrocopter in case of failure of one of four pairs of motor-screw are proposed. The basis of the proposed methods is to use a parachuting effect. Parachuting achieved by forced off the power of the motor, which is located at the opposite end of the same yoke as faulty motor As a result, the quadrocopter vertical speed at the moment landing is reduced significantly and is approaching a relatively safe value. The horizontal speed of an unmanned quadrocopter at moment landing, as well as the angle equals null.|
|Issue 8, Pages: 26-31|
|Inhomogeneous states of incommensurate ferroelectric thin film|
|I. Karpa, S. Sveleba, I. Katerynchuk, I. Kunyo, Ya. Shmygelsky|
|The physical phenomena in ferroelectric thin films with incommensurate phase are requires the rejection of the approach of constant amplitude during their phenomenological description. We are obtained the spatial dependence of amplitude and phase functions for the thin surface layer of ferroelectric in its incommensurate phase. It was concluded that size effects in thin-layer crystals should be visible when the length extrapolation is commensurate with the thickness of the crystal.|
|Issue 8, Pages: 32-38|
|Computer simulations of the defects and their impact on the energy properties in In0.5Tl0.5I of substitutional solid solutions|
|A. Kashuba, O. Bovgyra, O. Futey, I. Semkiv, A. Franiv, N. Kashuba|
|Currently, the properties of semiconductors and dielectrics with a layered crystalline structure are being intensely studied. These investigations seem promising because of the presence of three different crystallographic axes (à ≠ b ≠ c), which considerably expands their practical application. Single crystals of heavy metal halogenides like TlBr - TlI and TlCl - TlBr are of interest for applications in infrared optics and Cherenkov-light detector radiators. A better opportunity to manage in wide energy range the band gap Eg for practical applications exists with varying the cationic content of InI - TlI. The latter content InI - TlI is also perspective for applications in the wide spectral range - from visible to IR regions. The titled compounds may be considered as a particular class of binary semiconducting compounds possessing promising optical parameters. The traditional crystals with heavy cations, like TlI and Tl-In-I, may serve as the suitable modeling crystals and as those for the search and design of novel crystals. They possess a rare coexistence of the ionic and covalence chemical bonds which define a huge anisotropy of the effective masses and carrier mobility. Following these reason one can expect that growth of the corresponding solid crystalline state alloys may be perspective for the design of principally new materials with coexistence the long-range-ordered and locally disordered structures. As a continuation of previous investigations, in the present work, we perform DFT study of the cationic substituted binary compounds (InxTl1-xI). The calculations were realized within the generalized gradient approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) exchange-and-correlation functional. The interaction of electrons with the atomic cores was described with the Vanderbilt ultrasoft pseudopotentials. Computer simulations of the defects (vacancies and inter-nodal inclusions) in substitutional solid solutions (SSS) In0.5Tl0.5I are present. The dynamics of the parameters of the electron subsystem in SSS In0.5Tl0.5I has been studied theoretically making use of the pseudopotential method. The band-energy structure and density of states for the defective structures SSS In0.5Tl0.5I are present. The possibility of metallization of one of the crystallographic directions is established.|
|Issue 8, Pages: 39-50|
|Application finite element method in modelling formation mechanisms of the Earths structures|
|V. Fourman, M. Khomjak, L. Khomjak|
|The numeral integration technique to calculate the gravity anomalies of the geological bodies of complex geometry and different densities using the finite element approach and Gauss formulas is developed. In the two-dimensional case the solution algorithm of the direct gravity problem based on MS Excel is proposed. Its implementation in the program language VBA to simulate the test and modelling problems is used. The prospect of the further researches relatively more realistic three-dimensional problems as soon as software development is specified. Proven technique of numerical solving of the inverse problem of gravimetry on the basis of solving a direct problem and taking into account the local error of approximation of the region by finite elements method can be combined according to the structure for solving an integral problem, namely, the distribution of the thermomechanical characteristics of the Earths crust and mantle environments, rheologically heterogeneous, for a more comprehensive informative mapping of structural features and data on the spatial-temporal distribution of density, temperature and pressure. In the computer modeling method, the influence of such rheological parameters of the geological environment as layering, anisotropy, ductility and viscosity in the distribution of geodynamic, thermoconvertible and mechanical characteristics of geological structures at the local and regional levels in relation to the tasks of tectonophysics for modeling are taken into account. Of course, while this model can serve only as a zero approximation, its results need not be interpreted directly for real geological objects. However, if the topography is taken into account, the necessary amendments are made, specification of the distribution of densities, reconciliation with available geological and geophysical data, and also in the case of transition to three-dimensional models can be argued about the good prospect of such revised combined models of the interconnection of geodynamic, thermoconvex and mechanical characteristics geological structures of mountain structures and methods of their research on the basis of the proposed, rather simple algorithm and corresponding optimized software.|
|Issue 8, Pages: 51-58|
|Checking of linearity of dielectric response of layered GaSe crystals within range dominating by low-frequency dispersion|
|Linearity of dielectric response in frequency domain of low-resistivity GaSe layered crystals has been checked within the range dominating by low-frequency dispersion (LFD) or quasi-DC conduction (q-DC). The proposed method of linearity checking consists of double - sine and cosine - calculation of integral Fourier transform of spectrum of imaginary part of the complex capacity for later comparison with the spectrum of real part of complex capacity. Integral Fourier transforms were numerically calculated by interpolating the experimental spectra by cubic splines and using C++ language libraries of high-precision calculations GNU MPFR and ZKCM.|
|Issue 8, Pages: 59-65|
|Development of software for representation and analysis of scientific research results|
|O. Babych, Ya. Boyko, I. Gabriel, D. Slotvinsky|
|The software in C ++ programming language for creation of user interface and presentation and analysis of scientific research results was developed. The work of the software for the computer simulation of the temperature dependences of the coefficient and thermoelectric power S(T) of high-temperature superconductors (HTSC) has been analyzed and tested. The results of calculations made it possible to estimate the degree of influence of doping HTSC not only on the parameters of the band spectrum, but also on the critical temperature (Tc) and to follow the relationship between them. The obtained dependences are in accordance with the Anderson model: with the increase in the content of oxygen and the reduction of the concentration of impurities, the degree of ordering in the system increases. As a result of the narrowing of the band and the decline of localized states at its edges, the value of the function of the density of states at the Fermi level acquires large values and improves the superconducting properties. The correlation between Tc and the width of the conducting band W was found. The comparison of the Tc(W) dependence for Tl- and Bi-HTSC with Hg-HTSC was performed.|
|Issue 8, Pages: 66-73|
|Expert system of smartphones search, created as a WEB application on the basis of the Node.js platform|
|V. Grabovskyi, P.-R. Masliy|
Our application is a rules-based expert system, also known as a production system, of which knowledge base contains domain knowledge coded in the form of rules. The project-interface code is located in a views directory. It is divided into logical and structural units. In particular, pages "Home" and "Admin" are located in separate files. A common part of the code that connects the styles of their designs is also organized as a separate file, which allows modifying the styles of both pages in a single file. The styles of the interface design, the device images and the code, which are necessary for correct operation of the program, are located in a public directory. The database-connection code and the database code, which in itself represents a file that stores information in the JSON format, are located in a directory db. routes and expert directories contain a logical block that works with the data entered by a user, as well as a block that generates ranking of the devices presented in the database. The codes of the database and the search-engine blocks are separated, being located in public/js and routes directories, respectively. Finally, a public/js directory includes a code executed on a client side of the program in a web browser, whereas the code executed directly in the program is located in a routes directory.
The knowledge base and the search system created by us enable one to perform quick and expanded searching for smartphones with desired characteristics. Moreover, the software finds the websites with all the necessary information, including the websites of online stores where the smartphones can be purchased. Abilities for editing (modifying and adding) the knowledge base by users are also provided.
|Issue 8, Pages: 74-81|
|Dual-booting and multi-booting of Microsoft Windows family operating systems based on a virtual machine|
|In this work I have implemented method of using dual-booting and multi-booting based on the virtual machine using Microsoft Windows family operating systems, such as Windows 8.1, Windows 10, Windows Server 2016. For configuration of virtual machine with appropriate functionality were applied unpacked files of WIM-file and tools such as DISM, BCDboot. As a result, the virtual machine was able to load different operating systems in turn without changing its own configuration options. Operating-system-level virtualization was carried out based on the VMware Workstation Pro software. It has been found that the developed technique provides the possibility to create virtual machines, the architecture of which is more similar to the architecture of physical machines.|
|Issue 8, Pages: 82-92|
|The software package DiaControl|
|R. Lazirko, S. Sveleba, I. Katerynchuk|
|The software package DiaControl designed for diabetic users. It consist both desktop, web and mobile-interfaces. They are using the MySQL data base. The interfaces are written using the Java programming language and the markup languages of HTML and CSS. The developed software realize different levels of access, namely the patient - the doctor. This software package will help people with diabetes to control the course of the disease by the way of self-control. Also, this complex allows the physician to observe the history of the patients diet.|
|Issue 8, Pages: 93-101|
|Spectral approach for the template segmentation and object search|
|V. Parubochyi, R. Shuwar|
|The objects search and recognition are one of the most common tasks of digital image processing. Since they require high costs of computing, they are the slowest and most resource-consuming parts in a large number of image processing and recognition systems. It creates the need for simple and effective image recognition methods. Unfortunately, the most of the simple methods are also less effective. On the other hand, not all systems require extremely high accuracy and they can use more simple methods with the same success as complex ones. |
The article deals with the spectral approach to the implementation of template segmentation and the object search based on a two-dimensional discrete Fourier transform. The spectral template segmentation is a simple modification of the spatial template segmentation which uses Fourier spectrums of the template image and blocks of the analyzed image in the same way as the template image and blocks of the analyzed image are used in the spatial template segmentation. The implemented methods of the spectral template segmentation and object search were compared with the original methods of the spatial template segmentation and object search. On the basis of this comparison, the advantages and disadvantages of the proposed methods were investigated; the speed and accuracy of recognition and search of objects were estimated. Also, the influence of image spatial and texture modifications on the quality of the recognition and object search was considered. For spatial modifications of the image the image rotation at 45, 90 and 180 degrees was considered, and for texture modifications of the image the noise was added, the brightness was increased and decreased.
As a result, conclusions about the possibility of using the proposed methods in practical systems were drawn. Also, a number of approaches to optimize and improve the accuracy of the object recognition based on these methods were proposed.
|Issue 8, Pages: 102-110|
|Data asquisition system based on Raspberry Pi microcomputer|
|V. Goshovsky, V. Dzikovskyi, R. Mysiuk, V. Rabyk, I. Sasovets|
|Hardware and software implementation of a system for data acquisition from measurement instruments based on the Raspberry Pi microcomputer is described. This system gathers the data and sends them to the remote server for further loading into the database. The functional diagram for connecting the RE-205 and PBI-8 devices to the RS-485 interface is given. The mentioned devices are the temperature controller and the 8 channel temperature display, respectively. Another schematic diagram shows the implementation of RS-232 to RS-485 converter used for connection of RS-485 interface to the Raspberry Pi microcomputer. The ModBus-485 application for the Raspberry Pi (Raspbian) is written in C language. This app allows one to form queries to the network - connected RE-205 and PBI-8 devices, get data from them and store the measurement results in the SD card of the microcomputer as well as to check the reliability of those data. The functional diagram for gathering and transfer of the data is also given. |
The data transfer between the microcomputer and the server is possible via the Ethernet network, by a GSM module or via the Internet connection. The results of measurements can be stored at the computer as well as in the DropBox storage. The user can control the instruments using the Web interface, or an Android application, or by the Interface Control software for MS Windows. The dedicated web interface allows the user to remotely control the data acquisition process and view the data.
The Interface Control application (Android) for the smartphones makes it possible to set the connection with the DropBox, get and process the data from measurement devices. Also this application contains the interface to the My SQL database, allowing one to create the settings files for the devices, get the data files and visualize them.
|Issue 8, Pages: 111-117|
|Calculation of energy consumption model of smart house|
|L. Monastyrskii, Ya. Boyko, O. Petryshyn|
|The aim of this work was creating of heat regime management of smart house; witch satisfies conditions of comfort and economy. The investigation was dedicated calculation of minimization condition of payment of consumed energy heating of smart house. Saving is possible at the expense of different power supply tariffs. Cheaper payment was implemented by optimization time diagram of discrete inclusion of heater in different cost electroenergy tariff. If was installed values of minimum Emin and maximum Emax energy possible for house in condition of permanent inclusion of heater. Time step of introduced energy was equal to one hour. |
The model of smart house represents system of linear algebraic educations, solution of such give set possible chart options of discrete inclusions of heater. From a set of option was selected the case that answers minimum of payment of heating. It was created the calculation program by Python with using library Pulp. The code of program is given in the appendix.
|Issue 8, Pages: 118-126|
|Optimization of permanent magnet focusing system for submm clinotrons|
|K. Ilyenko, Yu. Novosel, T. Yatsenko|
|We propose to use optimized composite permanent magnet and iron insert focusing system that provides not only for a simpler assembly of the magnet pole pieces but also for insertion of more magnet material magnetized longitudinally into the preferable spatial positions. This has the potential of reducing total mass of the current in-house design (for the same given on-axis value of guide magnetic field) for modern compact submm-waveband clinotrons and other vacuum electron devices under development at the Department of Vacuum Electronics of O. Ya. Usikov IRE NAS of Ukraine by about 25 - 30 per cent while also decreasing the overall size of the magnet assembly as it allows us to put much less magnet material at larger transverse radial positions (where it is much less efficient in terms of mass-dimensional characteristics). To achieve such a goal, we use the known method of multiple decomposition of the permanent magnet system space together with our own developed methodology of geometric similarity based on the fact that magnetic field in a given point of space depends as the inverse cube of the distance to that point from the volume element with magnet material and is simultaneously proportional to the value of the volume of magnet material that creates the magnetic field. Major advantage of the proposed here design lies in the realization of the fact that iron field concentrators inserted in the both pole pieces of the focusing system, and used to avoid manufacturing complications of choosing the optimal magnetization angles for magnet material placed in different spatial positions of the system, may not occupy the total axial distance in each pole piece but can be reduced without loss of their efficiency to a portion of the axial distance whereas the rest of the axial distance could be fitted with magnet material magnetized in the optimal (longitudinal) direction. This either enhances the value of the guide magnetic field in the operational volume of the permanent magnet focusing system or can be used to remove less efficient magnet material from other parts of the permanent magnet focusing system thus reducing its overall mass and dimensions. A certain attention needs to be paid when choosing an appropriate model in optimization efforts as the iron concentrators are nonlinear elements. Optimization calculations were checked using the package CST Electromagnetic Studio.|
|Issue 8, Pages: 127-134|
|Influence of deformation and high-temperature annealing on dislocation-related electroluminescence of p-type silicon|
|B. Pavlyk, M. Kushlyk, D. Slobodzyan, R. Lys, J. Shykoryak, R. Didyk, I. Matvijishyn|
|This paper, reports about ongoing research on the restructuring of dislocation-related electroluminescence centers in structures based on p-Si doped with oxygen.The generation of dislocations was carried out in the process of uniaxial plastic deformation along  direction (p = 107 Pa, T = 1000 K). In order to increase the concentration of oxygen-containing complexes and to rebuild defect subsystem in a near-surface silicon layer, a hightemperature annealing (T = 1300 K) in the flow-oxygen atmosphere was made.|
It is shown that plastic deformation and high-temperature annealing in oxygen atmosphere generate high concentration of dislocations on silicon surface (107 ñm-2), which allows to create highly radiative Al-Si (p) structure. Electroluminescence spectra of these structures at different concentration of dislocations, duration of high-temperature annealing and pressure magnitude of elastic deformation were studied.
Such defects with the energy levels in the band gap Ev-0.08 eV (60° dislocation), Ev+0.14 eV (dislocation-V), Ev+0.26 eV (dislocation-O) correspond to dislocation-related electroluminescence (DEL) centers.
The elastic deformation has a slight impact to the intensity of bulk electroluminescense maximum intensity. For pressure values from 0 to 22 MPa, the intensity varies over the range of 1% from the 10 level. At the same time, as for the D2-D4 bands, the growth of the maximum intensity begins with pressure values of 10 MPa and up to 22 MPa. At maximum mechanical stress, the intensity value is ~ 1.5 times higher than the initial one. The evolution of the structural defects and impurities during the elastic stress increases intensity of D1-line (1.54µm). Modeling of the underlying physical processes has testified that the near-contact Si layers are strained. Such layers act as getter sites for the structural defects and impurities.
|Issue 8, Pages: 135-142|
|Impact of the process of measuring the p-Si crystals resistance on its value during the elastic deformation|
|B. Pavlyk, R. Didyk, R. Lys, J. Shykoryak, D. Slobodzyan|
|The influence of the resistance measurement process of p-Si crystals on its absolute magnitude has been investigated under the influence of elastic deformation and magnetic field (B = 0.354 Ò). |
It has been experimentally discovered that during measuring the resistance, its final value is not established immediately. It is established in 40-50 seconds once the sample is connected to an ohmmeter. It has been established the influence of the voltage applied to the sample on the results of the measurement of the R(σ) dependence. It has been shown that the external voltage, which coincided with the voltage polarity from the ohmmeter, causes an increase in the resistance of the crystals. The processing of the sample by an external electric field (1 V) causes an increase in the resistance change rate by almost an order of magnitude during the measurement R(σ).
A slow change in the resistance of the sample (within 5 %) in the magnetic field is observed. Resistance increases or decreases in turn. Changes in resistance over time (from growth to decrease) occur more often in an elastically deformed sample. The growth rates of resistance are greater compared to the rates of change in resistance of the sample, which was in a non-compressed state. Without the magnetic field, the nature of the dependence of the rate of change in the resistance of the sample from time t significantly differs from that described above.
|Issue 8, Pages: 143-152|
|The band structure and refractive parameters of potasium ammonium sulphate solid solution crystal|
|V. Stadnyk, P. Shchepanskyi, M. Rudysh, R. Brezvin, ². Ìàtviishyn, L. Karpliuk, Z. Kohut|
|In this work we present results of quantum chemistry calculations of the electronic and optical properties of the representative of potassium sulphate - ammonium sulphate system, K1.75[NH4]0.25SO4 crystal. Current research was motivated by performed so far experimental study of refractive indices and birefringence dispersions of the crystal, which revealed the increase of optical indicatrix symmetry at room temperature, not detected in either K2SO4 or (NH4)2SO4 crystals. Thus we found interesting to investigate the peculiarities of electronic structure of specified compound along with comparison of theoretically deduced refractive parameters with experimental data. |
Ab initio calculations of the band-energy structure, the distribution of the electronic density with contribution of individual atoms and dielectric function in this work are performed using ultrasoft pseudopotentials and generalized gradient approximation (GGA) in the framework of the density functional theory. As input parameters X-ray analysis data served. Before the calculations the optimization of the structure was performed. Optimized structure was for about 9.3 % increased in volume; maximal deviation from the experimentally established lattice parameters is on the level of 5.4 %. The coordinates of special points were: Ã(0; 0; 0); F(0; 0.5; 0), Q(0; 0,5; 0.5) and Z(0; 0; 0.5).
It is established that the band gap of the crystal is of a direct type and is equal Eg = 4.8 eV. The bottom of conduction band is formed mainly by the s-states of potassium atoms and the top of the valence band is formed by the oxygen p-electrons. Band structure of the crystal is characterized by a low dispersion of energy levels with an exception of lowest in conduction band in the vicinity of Brilluoin zone center which is rather typical for ABSO4-group crystals. The genesis of main bands of the crystal is established and contributions of individual atoms are discussed. Presence of NH4 complexes in the crystal leads to the decreasing of band gap value and insignificant changes in the band structure.
Imaginary part of dielectric function is calculated from the momentum matrix elements between the occupied and unoccupied wave-functions. From this, using Kramers-Kronig relation its real part was obtained. Knowing the real and imaginary parts of dielectric function the spectral dependences of refractive indices were deduced. The crystal reveals normal dispersion for three crystal optics directions in a visible spectrum region and satisfy the relation nz > nx > ny. Obtained results are in a good agreement with the experimental data.
|Issue 8, Pages: 153-157|
|Volodymyr Savchyn: remarkable experimental scientist. Remembering the collaboration|
|Some aspects of the activity of the distinguished professor Volodymyr Savchyn (04.04.1947-04.03.2013) are presented. Being a scientist and a teacher, he was also an incredibly skilled experimentalist, creating unique state-of-the-art setups, and a talented writer that published three textbooks on solid state physics. For the author of this paper, professor Volodymyr Savchyn was a friend and advisor through many years of collaboration.|
© Ivan Franko National University of Lviv, 2011
Developed and supported - Laboratory of high performance computing systems