Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

4-9

Authors: Wiktor Kania, Radoslaw Wajman

The project aimed to develop and implement an efficient web server in the C++ programming language. A highly concurrent network server was achieved using system calls such as polls and a limited number of threads. The server has built-in support for a new scripting language called Ckript. It is an original project that exposes most of the server’s functionality and is the primary way of developing back-end web applications. Ckript is an interpreted language with a strong typing system, garbage collection, semi-manual memory management, first-class functions, explicit variable references, support for certain object-oriented patterns and many others. In the article the syntax of the language but also the environment architecture has been explained. Finally, the testing procedure has been described with the results’ presentation and discussion at each step.

15-19

Authors: Borys Mokin, Vitalii Mokin, Oleksandr Mokin, Orken Mamyrbaev, Saule Smailova

The problem of creating mathematical models of nonlinear dynamical systems does not have an unambiguous solution and requires the creation of a separate synthesis method for each such object. To develop a method for synthesizing mathematical models of an extensive class of nonlinear dynamical systems with polynomial nonlinearities. The work uses a method based on the solution of the Volterra integral equation in the ideology set forth in Van Trees H.L., according to which the structure of a nonlinear dynamical object present47s a series connection of the linear part, characterizing the inertial properties of the system, and the nonlinear element, given by static characteristic. The difference of the suggested version of the method from the classical one, proposed in the works of Van Trees H.L., is an expansion of their input and output signals into Fourier series and a representation of the inertial part of these systems by their Bode plots, connected into one structure with input and output signals and non-linearity by Volterra integral equation. The algorithm of the proposed method is disclosed by the example of solving the problem of identifying a nonlinear dynamical system which impulse response of the inertial part satisfies the separability requirement, the order of the polynomial nonlinearity is three, and the model of the input signal has the form of a sinusoid "raised" over the time axis on a priori given constant level. A computational experiment was carried out on the example of nonlinear dynamical systems with the third order of the nonlinear characteristic and the first and second orders of the model of the inertial part of these systems with the specified algorithms of their parametric identification. The suggested method allows to synthesis the mathematical model of a nonlinear dynamical system with the polynomial static characteristic to the case when the input signal has an arbitrary number of harmonics, and the model of the inertial part and the nonlinear polynomial function have an arbitrary order.

24-29

Authors: Nataliia Stelmakh, Oleg Belman

The paper regards the urgency of creating small - sized systems for automated local sorting of household waste for modern residential complexes based on visual spectrometry. For this purpose, algorithms for system operation were developed and the procedure for designing a functional control scheme for the sorting process with the construction of the necessary contours of automated control was presented.

34-37

Authors: Serhii Zakharchenko, Tetiana Korobeinikova, Aigul Tungatarova, Bakhyt Yeraliyeva

A new method of successive approximation ADC calibration without interruption of the main conversion process is proposed. The method is based on the use of information redundancy in the form of redundant positional number systems. The method is based on the selection and analysis of unused combinations in the redundant ADC conversion characteristic.

43-49

Authors: Alexander Osadchuk, Iaroslav Osadchuk, Volodymyr Martyniuk, Lyudmila Krylik, Maria Evseeva

A new magnetically sensitive element based on the synthesized semiconductor material has been developed. A method for the synthesis of a complex compound has been developed tetrakis-µ3-(methoxo) (methanol)-pentakis (acetylacetonate) (tricuprum (II), neodymium (III)) methanol (I). The scheme of arrangement of chemical bonds for this complex compound is offered. Conducted properties have been studied tetrakis-µ3-(methoxo) (methanol)-pentakis (acetylacetonate) (tricuprum (II), neodymium (III)) methanol (I) in compressed form in the temperature range 273 - 493 K showed that conductivity varies from 5.67 ∙ 10-14 (Ohm ∙ m)-1 at a temperature of 273 K to 1.06 (Ohm∙m)-1 at a temperature of 493 K. The experiment showed that in the temperature range 303 - 423 K resistivity of the pressed sample of the test material of compound (I) decreases from 2∙1010 Ohm∙m to 5 ∙ 102 Ohm∙m, ie the isolated compound is a semiconductor. In the developed magnetoresistor when changing the induction of the magnetic field from 10-3 to 200 mT, the resistivity varies from 3.12∙10-5 Ohm to 1.25∙10-2 Ohm∙m, and from 200 mT to 1 T, the resistivity varies from1.25∙10-2 Ohm to 0.3 Ohm. On the basis of the developed magnetically sensitive resistive element the circuit solution of the frequency transducer of a magnetic field is offered. The frequency transducer of the magnetic field is a hybrid integrated circuit consisting of a bipolar transistor and a gate gate transistor, which creates the preconditions for the creation of an autogenerator device, the feedback circuit of which includes a magnetically sensitive resistor based on tetrakis-µ3- (methoxo) (methanol)-pentakis (acetylacetonate) (tricuprum (II), neodymium (III)) methanol (I).The frequency of generation of the developed transducer increases the most in the range from 10-3 T to 0.2 T, and at a supply voltage of 5.0 V varies from 250 kHz to 600 kHz, and in the whole range of changes in magnetic field induction varies from 250 kHz to 750 kHz. The sensitivity of the developed device with frequency output for measuring the induction of the magnetic field is from 400 Hz/mT to 800 Hz/mT.

56-59

Authors: Kostyantyn Ovchynnykov, Oleksandr Vasilevskyi, Volodymyr Sevastianov, Yurii Polievoda, Aliya Kalizhanova , Bakhyt Yeraliyeva

The article provides an analysis of the physical processes underlying the operation of the measuring transducer, with a time based information presentation. A mathematical model is developed that describes the process of free oscillation attenuation excited in the LC-contour of primary measuring transducer, and analyzes and evaluates the influence of external factors that influence the measurement results. The ways of elimination of their influence on the results of measuring control are offered.

64-68

Authors: Tomasz Rymarczyk, Jan Sikora

The accuracy of the calculation of acoustic problems formulated in the frequency domain is presented in this work. The issues of the acoustic point sources modelling were discussed and the influence of frequency as well as the impact of the geometry of the analysed area on the accuracy of calculations were indicated. Speaking about the influence of geometry, we mean not only discretization but also the configuration of the considered area, such as for example point sources localization close to the outer edge.

73-76

Authors: Monika Styła, Sebastian Styła

The paper presents a numerical electromagnetic simulations of SAR limited to human tissues based on FDTD algorithm using Sim4Life platform. Flat-bottomed dielectric vessel (flat phantom) and half-wave symmetric dipole antenna were modeled. Simulations were done for the frequencies 0.9 GHz and 0.6 GHz. The analysis were performed according to the IEEE/IEC62704-1 standard and include distributions of electric and magnetic fields around the phantom and antenna. Finally, SAR distributions in the phantom and near the antenna.

4-9

Authors: Serhii Moroz, Anatolii Tkachuk, Mykola Khvyshchun, Stanislav Prystupa, Mykola Yevsiuk

The analysis of mobile communication standards is carried out, the functional structure and interfaces of interaction between the structural elements of the cellular network are considered. To understand the principle of communication according to the GSM standard, a block diagram of a mobile switching center (MSC), base station equipment (BSS), control and service center (MCC), mobile stations (MS) is presented. The main algorithms for ensuring the confidentiality and security of mobile subscribers' data, in different types of standards, as well as the vulnerabilities of information flows are considered. In particular, the following dangerous types of attacks have been identified, to which mobile network subscribers are sensitive: sniffing; leakage of personal data; leakage of geolocation data; spoofing; remote capture of SIM-card, execution of arbitrary code (RCE); denial of service (DoS). It is established that the necessary function of the mobile network is the identification of subscribers, which is performed by IMSI, which is recorded in the SIM card of the subscriber and the HLR of the operator. To protect against spoofing, the network authenticates the subscriber before starting its service. In the case of subscriber identification, the subscriber and the network operator are protected from the effects of fraudulent access. In addition, the user must be protected from eavesdropping. This is achieved by encrypting the data transmitted over the radio interface. Thus, user authentication in UMTS, as well as in the GSM network, is carried out using encryption with a common key using the "hack-response" protocol (the authenticating party sends a random number to the authenticated party, which encrypts it according to a certain algorithm using a common key and returns the result back).

15-19

Authors: Dominik Gnaś, Przemysław Adamkiewicz

This paper discusses two ways of measuring the distance between the transmitter and the receiver using UWB technology, then identifies their advantages and disadvantages. The method of calculating the position is presented together with the method of predicting errors based on room geometry. The hardware configuration of the transmitter and receiver systems included in a location system based on UWB technology is explained. Bluetooth technology is discussed, which is used to connect the location system with the environmental monitoring system.

24-27

Authors: Damian Harasim

This publication presents the basic assumptions about the light guiding mechanisms in tilted fiber Bragg gratings, transmission spectra of the fiber with such structures and their sensor properties related to the occurrence of the so-called cladding modes. The light in the form of modes coupled to the optical fiber cladding causes their spectral properties to depend on the difference in the refractive indices of the surrounding medium and the fiber cladding. With the introduction of a small inclination angle of the diffraction fringes forming the Bragg grating, the cladding modes show sensitivity to changes in the refractive index of the environment of aqueous solutions, which makes the spectrum of their applications broad. This publication presents changes in the spectra of selected modes measured for solutions with a specific refractive index, shift sensitivity, and changes in the mode transmission coefficient and processing characteristics at a selected concentration range of solutions. Experimental results show that high order cladding modes respond both by shifting the central wavelength as well as by changing the transmission minimum. In selected ranges, these parameters show a linear characteristic as a function of changes in the concentration of the cane sugar aqueous solution. In the case of TFBG with a tilt angle of 8 °, the sensitivity of wavelength changes is 0.012nm / RIU for solutions with concentrations ranging from 0% to 10% by weight.

36-39

Authors: Aleksandra Wilczyńska, Karolina Czarnacka, Andrzej Kociubiński, Tomasz Kołtunowicz

In this paper, the transport properties of discontinuous 4 nm copper layers obtained by dual-source non-reactive magnetron sputtering in the presence of argon are presented. The value of resistance and capacitance of the current parallel to the plane of these layers can be adjusted independently by changing the nominal thickness of the metallization. The influence of frequency on the conductivity of the obtained structures in the range from 4 Hz to 8 MHz was studied. Additionally, in order to compare the non-oxidized and oxidized layers, some of them were heated at 500 °C. Based on the results obtained, the mechanism of electric charge transfer was determined, the knowledge of which is essential for planning further experiments based on this sputtering method and potential selection of future application of the structures. Statistical measurements at room temperature will serve as a reference for the conductivity and resistivity values obtained by mathematical calculations from measurements of resistance, capacitance, phase shift angle, and dielectric loss tangent as a function of temperature from 20 K to 375 K, which are expected in further studies on the obtained structures. The work is an introduction to the technology of obtaining multi-layer metal-dielectric structures.

44-46

Authors: Oleksii Perepelytsia, Tetyana Nosova

Apexlocators are devices that determine the working length of the root canal. Measurement with the help of alternating currents of different frequencies in combination with the method of the ratio allows to achieve high accuracy in determining the location of the physiological tip of the root (over 80%). However, such devices cannot accurately visualize where a doctor's tool is. Using image processing algorithms, you can segment tooth root structures with high precision. Therefore, the combination of electronic determination of the root canal length (using apexlocator) with X-ray segmentation is relevant.

4-8

Authors: Tomasz Rymarczyk, Jan Sikora

Two ways of approximation of the BEM kernel singularity are presented in this paper. Based on these approximations extensive error analysis was carried on. As a criterion the preciseness and simplicity of approximation were selected. Simplicity because such approach would be applied for the tomography problems, so time of execution plays particularly significant role. One of the approximations which could be applied for the wide range of the arguments of the kernel were selected.

14-17

Authors: Volodymyr Barannik, Natalia Barannik, Oleksandr Slobodyanyuk

It is shown that the current direction of increasing the safety of information resources when transmitting information in info-communication systems is the use of methods of steganographic instruction in video imagery. The effectiveness of such methods is significantly increased when used in a complex of methods of concealment, which are based on the principles of inconsistent and cosmic communication. At the same time, existing methods of steganographic are used in the process of insertion of information mainly only laws, empty features of visual perception of video images. So, it is justified that the scientific and applied problem, which is to increase the density of embedded messages in the video container with a given level of their reliability, is relevant. The solution of this problem is based on the solution of the contradiction, which concerns the fact that increasing the density of embedded data leads to a decrease in the bit rate of the video container, steganalysis stability, reliability of special information, and video container. Therefore, the research aims to develop a methodology for the steganographic embedding of information, taking into account the regularities of the video container, which are generated by its structural and structural-statistical features. The solution to the posed problem of applying steganographic transformations is proposed to be realised by methods of indirectly embedding parts of the hidden message in certain conditions or functional relationships. The possibility of creating steganographic transformations regarding the indirect embedding and extraction of hidden information in a multiadic basis by modifying the underlying basis system within an admissible set is demonstrated. It is shown that the multiadic system, which is created in the spectral space of DCT transforms, has the potential to form a set of admissible modifications of basis systems.

22-27

Authors: Paweł Kowalski, Piotr Tojza

The article proposes an efficient line detection method using a 2D convolution filter. The proposed method was compared with the Hough transform, the most popular method of straight lines detection. The developed method is suitable for local detection of straight lines with a slope from -45˚ to 45˚. Also, it can be used for curve detection which shape is approximated with the short straight sections. The new method is characterized by a constant computational cost regardless of the number of set pixels. The convolution is performed using the logical conjunction and sum operations. Moreover, design of the developed filter and the method of filtration allows for parallelization. Due to constant computation cost, the new method is suitable for implementation in the hardware structure of real-time image processing systems.

32-37

Authors: Przemysław Falkowski-Gilski

Today, thanks to mobile devices, satellite communication is available to anyone and everywhere. Gaining information on one’s position using GNSS (Global Navigation Satellite Systems), particularly in unknown urban environments, had become an everyday activity. With the widespread of mobile devices, particularly smartphones, each person can obtain information considering his or her location anytime and everywhere. This paper is focused on a study, considering the quality of satellite communication in case of selected mobile terminals. It describes a measurement campaign carried out in varying urban environments, including a set of Android-powered smartphones coming from different manufacturers. Based on this, respective conclusions and remarks are given, which can aid consumers as well as device manufacturers and application developers.

42-46

Authors: Jacek Klimek

The article discusses the principle of operation and the structure of chirped and uniform gratings. It presents the method of producing gratings with monotonic apodisation characteristics, and compares the spectral features of produced gratings with the those obtained by mathematical modelling.

51-54

Authors: Bartłomiej Stefańczak

The article presents the design of a four-wire, three-level AC/DC converter. The converter was controlled with the use of a proportional-resonant controllers based voltage oriented control (VOC). The implemented topology of the AC/DC converter allows to control each of the phases separately. This translates into the possibility of independent control of active and reactive power in each of the phases. In addition, the DC bus of the AC/DC converter is connected in parallel with the energy storage via an isolated DC/DC converter and with a renewable energy sources. The tests were carried out with the use of the designed converter, DSP controller and Matlab/SIMULNIK platform, which was used for automatic code generation. The results obtained show that independent control of each of the phases is possible, however, the operation with large power unbalances on each of the phases leads to large current pulsation on the DC bus. This is a phenomenon that threatens the correct operation of the energy storage. As a result, the level of asymmetry between phases should be limited to the level acceptable by the energy storage.

62-66

Authors: Dawid Zarzeczny

Currently, various methods are used to assess the biocompatibility of materials. After an in-depth and detailed review of the literature, the method used in the research was selected. As part of the experiments, a method based on the analysis of the values ​​of electrical parameters of cell cultures measured in the presence of electrodes was used. The electrode is a structure made of a thin layer of metallization. It measures the change in resistance, impedance and capacity of a mixture of cells and the substance in which they are grown. The plate containing the electrode assembly is called the measurement matrix. Currently, commercially used test matrices are made of gold or platinum. However, their high price means that large-scale research is significantly limited. In order to increase the access to the widespread use of this method, it was decided that it was necessary to use cheaper materials, reducing the necessary costs of conducting experiments. Considering this, an attempt was made to use a different conductive material to build matrices compatible with the ECIS® Z-Theta measurement system. Their use would enable in vitro research on living cells. In the presented work, titanium was used as a material that may turn out to be an alternative to the materials currently used. Its application to the production of matrices will allow to study the influence of this metal on the behavior of cells.

75-77

Authors: Jarosław Tatarczak

This work presents measurement results of pollutants generated during 3D printing. The measure of pollutants is the concentration of particulate matter with a diameter of up to 2.5 μm (PM2,5). Materials acrylonitrile-butadiene-styrene (ABS), polyactide (PLA) for a 3D printer and low-cost particulate matter concentration sensors PMS3003, PMS7003 were used in the research. Research results show that low-cost sensors can be useful for monitoring pollution during 3D printing in offices, laboratories or private homes.

4-8

Authors: Andrii Rudyk, Andriy Semenov, Olena Semenova, Sergey Kakovkin

The paper outlines the latest technologies used by the world's leading manufacturers in the development of mobile low-observable robotic systems and promising measures to improve the quality of components and design of such objects. Methods of detecting objects using stealth technologies are considered, and it is shown that only due to a system approach it is possible to compensate for the reduction of the effective scattering surface of low-observable objects by technical means of radar stations. It is shown that the main method of increasing the range to the radio horizont is the use of an air-based radar. Methods of detecting objects on the traces of their interaction with the environment are promising for organization of cooperation of several radars in the detection of low-observable objects.

14-17

Authors: Anzhelika Stakhova, Volodymyr Kvasnikov

The current state of control of vibration measuring equipment is studied in the work, the analysis of technologies of control of vibrating measuring machine equipment is carried out. It is determined that during the control a sufficient requirement for the analysis of changes in the state over time is to conduct periodic vibration measurements in the same modes of operation of the object. Therefore, the urgent task is to increase the reliability and accuracy of measurement results. It can be enhanced by obtaining additional information. For this purpose, recommendations for optimizing the vibration control points of the mechanism are formed. To increase the accuracy of measurement results when controlling the equipment for vibration signals, the methods of mounting the measuring transducer in the equipment monitoring system are considered. It is shown that the method of mounting the measuring transducer can affect the results of vibration measurements.

22-29

Authors: Yaroslav A. Kulyk, Bohdan P. Knysh, Roman V. Maslii, Roman N. Kvyetnyy, Valentyna V. Shcherba, Anatoliy Ia. Kulyk

In the article are presented the results of researches that touch the problem of the reliability improvement of determining the impurities concentration in biological objects in liquid by using the method of gas discharge visualization. There is an improved analysis method for biological objects in liquid based on gas discharge visualization (GDV), proposed criteria approach towards the assessment of liquid bio object’s composition applying this method, presented the assessment of the nature of liquid bio objects, which use the intensity of spectral components of its radiation has gotten during GDV. There is a developed and researched math model of ignition of a crown discharge and the dependency of spectrum intensity of radiation of liquid-phase biological object on its chemical composition proposed a conversion function for the assessment of the impurities concentration, together with the informative parameters of GDV images. All the results of the experimental researches of GDV and spectral composition of liquid-phase biological objects (LPBO) are presented in the article. The proposed approach lets specify the range of Mg concentrations in an oral fluid (OF) at various thyroid disorders obtained by the trilonometric method. It was found that the concentration of Mg in oral fluid of patients without thyroid disease is 12.73 ± 2.16 mg/l, patients with risk factors for thyroid disease have a concentration of 14.98 ± 1.92 mg/l, patients with sporadic goiter have a concentration of 26.65 ± 3.73 mg/l. Such data allow providing the patients with a better diagnosis of pathological disorders in glandular thyroids that are based on the concentration of Mg in oral fluid. It is confirmed that the concentration of Mg in oral fluid greater than 15 mg/l may indicate the presence of trilonometric pathology, including the focal thyroid gland.

34-39

Authors: Vladislav Kutsman, Oleh Kolesnytskyj

The article proposes a method for dynamic signature identification based on a spiking neural network. Three dynamic signature parameters l(t), xy(t), p(t) are used, which are invariant to the signature slope angle, and after their normalization, also to the signature spatial and temporal scales. These dynamic parameters are fed to the spiking neural network for recognition simultaneously in the form of time series without preliminary transformation into a vector of static features, which, on the one hand, simplifies the method due to the absence of complex computational transformation procedures, and on the other hand, prevents the loss of useful information, and therefore increases the accuracy and reliability of signature identification and recognition (especially when recognizing forged signatures that are highly correlated with the genuine). The spiking neural network used has a simple training procedure, and not all neurons of the network are trained, but only the output ones. If it is necessary to add new signatures, it is not necessary to retrain the entire network as a whole, but it is enough to add several output neurons and learn only their connections. In the results of experimental studies of the software implementation of the proposed system, it’s EER = 3.9% was found when identifying skilled forgeries and EER = 0.17% when identifying random forgeries.

45-49

Authors: Bartosz Wijatkowski, Jakub Smołka, Maciej Celiński

The aim of this research is to check which of two devices the keyboard or the controller – has a positive effect on a player's game-play in a platform game. Four parameters are defined: death count, error count, game time, learning time. A custom game is designed and implemented specifically for the research. The conducted experiment is divided into thirty-minute sessions, during which one player participates in the game after getting acquainted with the game’s mechanics. After completing the game, he/she fills out a survey in which he/she can express his/her level of satisfaction while using the assigned device. Each player has only one attempt. 16 players agree to participate. They are divided into two groups of 8 people each. Participants in the first group use the keyboard while those in the second group use the controller. In order to determine final results for the tested devices, the AHP method is used. The importance values for all pairs of measured parameters are determined in order to calculate their priorities. The priorities allow for distinguishing important from less important parameters. For this purpose, a survey of experienced players is conducted. They help to identify parameter importance. After trials and analysis of responses from the game-play satisfaction and parameter importance surveys, it turns out that players using the keyboard achieve better results, and the keyboard is more satisfying to use.

4-13

Authors: Taras Panskyi, Volodymyr Mosorov

A variety of clustering validation indices (CVIs) aimed at validating the results of clustering analysis and determining which clustering algorithm performs best. Different validation indices may be appropriate for different clustering algorithms or partition dissimilarity measures; however, the best suitable index to use in practice remains unknown. A single CVI is generally unable to handle the wide variability and scalability of the data and cope successfully with all the contexts. Therefore, one of the popular approaches is to use a combination of multiple CVIs and fuse their votes into the final decision. The aim of this work is to analyze the majority-based decision fusion method. Thus, the experimental work consisted of designing and implementing the NbClust majority-based decision fusion method and then evaluating the CVIs performance with different clustering algorithms and dissimilarity measures in order to discover the best validation configuration. Moreover, the author proposed to enhance the standard majority-based decision fusion method with straightforward rules for the maximum efficiency of the validation procedure. The result showed that the designed enhanced method with an invasive validation configuration could cope with almost all data sets (99%) with different experimental factors (density, dimensionality, number of clusters, etc.).

22-25

Authors: Pavlo Ratushnyi, Yosyp Bilynskyi, Stepan Zhyvotivskyi

In this work, the problems of research of ultrasonic images of joints are formulated. It is that for early diagnosis of developmental disorders of the hip joints needs to take frequent pictures, and the least harmful to health is ultrasound. But the quality of such images is not sufficient for high-quality automated measurement of geometric parameters and diagnosis of deviations. The ultrasound image of the hip joint is evaluated by quantifying the exact values of the acetabular angle, the angle of inclination of the cartilaginous lip, and the location of the center of the femoral head. To get these geometric parameters, you need to have clear images of objects. And for the operation of automated computer measurement systems, it is necessary to use such methods of pre-digital image processing, which would give clear contours of objects. Known and available image processing algorithms, in particular contour selection, face problems in processing specific medical images. It is proposed to use the developed method of sharpening to further obtain high-quality contour lines of objects. A mathematical model of the method is presented, which is a formula for converting the intensity values of each pixel of a digital image. As a result of this method, the noise component of the image is reduced, and the intensity differences between the background and the objects are increased, and the width of these differences is one pixel. The algorithm of a sequence of processing of ultrasonic images and features of its application have resulted. The results of the developed set of methods are given. The paper presents the results of processing the real image of the hip joint, which visually confirms the quality of the selection of objects on view.

30-35

Authors: Marcin Wardach, Paweł Prajzendanc, Kamil Cierzniewski, Michał Cichowicz, Szymon Pacholski, Mikołaj Wiszniewski, Krzysztof Baradziej, Szymon Osipowicz

This paper presents the design and research results of a claw pole machine with hybrid excitation. This machine is excited by permanent magnets and an electromagnetic coil. Both excitation sources are located in the rotor of the machine. Additionally, the rotor is made of a laminated core. This approach facilitates the process of its construction and enables the implementation of even very complicated structure of the rotor, which would be difficult in case of making the rotor from a one piece of material. This paper presents the construction as well as the results of simulation and experimental tests of the machine prototype. The tests showed that the proposed machine has the ability to adjust the voltage in a wide range. Such as a feature could be used, for example, to increase the speed of motor operation in case of an electric vehicle application, but also to regulate the voltage in wind turbines which generators operate at varying rotor speeds resulting from changing wind speed.

40-43

Authors: Klara Janiga

In low-voltage power networks with a large share of distributed energy sources, the phenomenon of overvoltage is increasingly observed. Although it may be desirable to raise the voltage value downstream of the network, in some cases the upper allowable voltage limit is exceeded. The method of eliminating voltage rises commonly used in the Polish power system is the installation of overvoltage protections, disconnecting the source from the grid. Such action reduces the profitability of prosumer installations, discouraging future potential investors. It turns out, however, that this is not the only disadvantage of such a solution. Sudden and uncoordinated disconnections and reconnections of more energy sources cause abrupt voltage changes that negatively affect the voltage conditions in the network. The aim of the paper is to present the operating algorithms of a standard overvoltage relay used in inverters of photovoltaic microinstallations. These algorithms – described in standards and national regulations – were tested in a typical inverter used in public low-voltage networks and implemented in the created simulation model of the relay. The described tests will be used for further work to demonstrate the need to coordinate the operation of overvoltage protections or replace them with other measures to improve voltage conditions in the grid with high share of photovoltaic sources.

48-51

Authors: Anzhelika Stakhova, Volodymyr Kvasnikov

It is known that vibration is generated to one degree or another by all moving parts of machines. Vibration processes arising in the process of functioning of machines and equipment are highly informative, reflecting the technical condition of many parts and assemblies quite fully. Therefore, the use of vibration diagnostics systems makes it possible to determine a defect even at the stage of inception, thereby excluding emergency stops of machinery. An urgent task is to create a vibration analysis device, which consists of a sensor for measuring vibration, the principle of operation of which is based on the use of a direct piezoelectric effect. The output signal of the sensor will go to a personal computer or any other device with the Windows operating system, where a spectral analysis of the measured vibration signal is carried out using a Matlab-based diagnostic program.

56-60

Authors: Jacek Wilk-Jakubowski

Satellites are the transmission medium for providing connectivity and building global, continental, or regional networks around the world (satellite operators effectively use satellites to support Internet traffic), and point-to-point connections are also possible. In practical use, there are combinations of VSAT networks with terrestrial wireless extensions, allowing end users to increase the capabilities offered via satellite. This paper provides selected information on broadband satellite networks using VSAT technology, including available protocols and transmission platforms. The aim of the article is also to present the chosen technical aspects of satellite networks working with the usage of VSAT technology.