# Вимірювальна техніка та метрологія. – 2022. – Випуск 83, №3

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** Measuring Equipment and Metrology : scientific journal. – Lviv : Lviv Politechnic Publishing House, 2022. – Volume 83, № 3. – 48 р. **

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Item Зміст до “Вимірювальна техніка та метрологія”(Видавництво Львівської політехніки, 2022-02-28)Item Calibration of analyzers of the mobile communication system parameters(Видавництво Львівської політехніки, 2022-02-28) Meshcheriak, Oleh; Velychko, Oleh; State Enterprise “Ukrmetrteststandard”The creation and operation of mobile communication systems is impossible without determining the parameters of base stations and mobile communication systems. For these purposes, appropriate devices are used that optimally combine testing capabilities in a single portable solution, which eliminates the need for several separate control and measuring devices. One of the main types of measurements of such devices is the measurement of the power of ultra-high and extremely high frequency signals. The article presents the method of calibrating meters of directional and absorbed power of ultra-high and extremely high frequency signals using the Bird 5000-EX mobile communication system parameter analyzers complete with the Power Sensor 5010V sensor and measuring sensors, Anritsu CellMaster MT8212EA and Arnitsu SiteMaster S331E spectrum analyzers. Calibration schemes for analyzers of parameters of mobile communication systems and analyzers of mobile communication base stations (hereinafter referred to as analyzers) have been developed. A measurement model of the analyzers based on the parameters of the directional and absorbed power of ultra-high and extremely high frequency signals based on the developed calibration schemes was created. The contribution of each component of the measurement model to the calibration result and the corresponding uncertainties of the model components were determined. The measurement uncertainty budget was made based on the proposed analyzer calibration model. The influence of the most significant influential values on the accuracy of measurement results was analyzed. The content of quantitative and qualitative indicators of corrections, which must be taken into account during calibration to achieve the highest accuracy of measurements, is revealed. The practical results of studies of measurement instability are given. The analyzer calibration method described in the article can be used in calibration laboratories that have the appropriate equipment and standards.Item Direct solution of polynomial regression of order up to 3(Видавництво Львівської політехніки, 2022-02-28) Dorozhovets, Mykhaylo; Lviv Polytechnic National UniversityThis article presents results related to the direct solution of the polynomial regression parameters based on the analytical solving of regression equations. The analytical solution is based on the normalization of the values of independent quantity with equidistance steps. The proposed solution does not need to directly solve a system of polynomial regression equations. The direct expressions to calculate estimators of regression coefficients, their standard deviations, and also standard and expanded deviation of polynomial functions are given. For a given number of measurement points, the parameters of these expressions have the same values independently of the range of input quantity. The proposed solution is illustrated by a numerical example used from a literature source.Item Calibration of quartz electronic stopwatchers comparison method using a digital camera(Видавництво Львівської політехніки, 2022-02-28) Meshcheriak, Oleh; Velychko, Oleh; State Enterprise “Ukrmetrteststandard”Measurement of time intervals with low accuracy on intervals from a few seconds to several hours or days is relevant for some broad applications in various fields of activity. Such measurements are widely used in the technological processes of various enterprises during the preparation and quality control of the preparation of medicines, during the maintenance of technical equipment and mechanisms, chemical technological processes, etc. For such measurements, manual electronic quartz stopwatches are widely used, which, despite their not too high measurement accuracy, must guarantee users the accuracy of measurements within the tolerance established by the technical documentation, since the risks of using untested measuring equipment are quite high, or generally unacceptable especially in the medical field. The issue of calibrating quartz electronic stopwatches by various methods remains relevant for many of their applications. The article discusses the calibration of quartz electronic stopwatches by the method of comparison using a digital camera. A calibration scheme for stopwatches was developed and a calibration measurement model was created based on the developed calibration scheme. The contribution of each component of the measurement model to the calibration result and the corresponding uncertainties of the model components were determined. The measurement uncertainty budget was made based on the proposed stopwatch calibration model. The influence of the most significant influential values on the accuracy of measurement results was analyzed. The content of quantitative and qualitative correction indicators, which must be taken into account during calibration to achieve the highest accuracy of measurements, is revealed. The method of calibrating stopwatches described in the article can be used in calibration laboratories that have the appropriate equipment and standards.Item Investigation of sensitive elements of temperature transducers based on thermometric material Lu1-xScxNiSb(Видавництво Львівської політехніки, 2022-02-28) Pashkevych, Volodymyr; Krayovskyy, Volodymyr; Haranuk, Petro; Romaka, Volodymyr; Stadnyk, Yuriy; Romaka, Lyubov; Horyn, Andriy; Lviv Polytechnic National University; Ivan Franko National University of LvivThe results of experimental studies of sensitive elements of temperature transducers based on semiconductor thermometric material Lu1-xScxNiSb, x = 0.01–0.10, are presented. Thermometric materials Lu1-xScxNiSb were made by fusing a mixture of components in an electric arc furnace with a tungsten electrode (cathode) in an atmosphere of purified argon under a pressure of 0.1 kPa on a copper water-cooled hearth (anode). Heat treatment of alloys consisted of homogenizing annealing for 720 h in vacuumed to 1.0 PA at a temperature of 1073 K. Arrays of diffraction data of X-ray diffraction studies were obtained on a powder diffractometer STOE STADI-P, and using the program Fullprof calculated structural characteristics. The chemical and phase compositions of the samples were monitored by metallographic analysis (scanning electron microscope Tescan Vega 3 LMU). The basis of the sensitive element of the resistance thermometer on Lu1-xScxNiSb materials is polycrystalline samples in the form of rectangular parallelepipeds with a size of 0.5×0.5×5 (mm3), to which the contacts are made of copper and/or platinum wire. Experimental measurements of electrical resistance values were performed using the four-contact method, and the values of the thermopower coefficient by the potentiometric method concerning copper and/or platinum. The thermoelectric pair platinumthermometric material was the basis of the thermoelectric converter. Modeling of thermometric characteristics of sensitive elements of the thermometer of resistance of the thermoelectric converter is carried out by a full potential method of linearized plane waves (Full Potential Linearized Augmented Plane Waves, Elk software package). The results of experimental measurements served as reference currents in modeling the characteristics.X-ray phase analysis showed the homogeneity of the studied samples of thermometric materials Lu1-xScxNiSb, as evidenced by the absence of traces of extraneous phases on the diffractograms. The dependences of the period of the unit cell a(x) Lu1-xScxNiSb are not linear, which indicates more complex structural changes than the one-act substitution of the Lu atom by Sc. Measurements of the values of the specific magnetic susceptibility χ (T, x) were performed by the relative Faraday method at T = 273 K using a thermogravimetric installation with an electronic microbalance EM-5-ZMP in magnetic fields up to 10 kGs. Experimental studies of the specific magnetic susceptibility of χ(x) sensitive elements have shown that the samples at all concentrations are Pauli paramagnetics, and the value of χ(x) is determined by the electron gas. In this case, the values of the magnetic susceptibility χ(x) are proportional to the density of electronic states at the Fermi level g(εF). In the area of concentrationsx = 0–0.02, the values of magnetic susceptibility χ(x) undergo insignificant changes, which indicates small changes in the concentration of current carriers. At a concentration x > 0.02 there is a rapid increase in the density of electronic states at the Fermi level g(εF), indicating an increase in the concentration of free current carriers. The presence of high-temperature activation sites on the temperature dependences of the resistivity ln(ρ(1/T)) for all Lu1- xScxNiSb samples indicates the location of the Fermi level εF in the band gap εg of the semiconductor, and positive values of the thermopower coefficient α(T) specify its position – near the valence band εV. The main carriers of electric current are holes. The nature of the behavior of the resistivity ρ (x, T) Lu1-xScxNiSb at all temperatures also corresponds to the results of modeling the kinetic properties. The fact that in the range of concentrations x = 0–0.04 the values of the resistivity ρ (x, T) Lu1-xScxNiSb change slightly at all temperatures indicates a significant advantage of the concentration of holes over electrons. This is indicated by positive values of the thermopower coefficient α (x, T). At concentrations x ≥ 0.04, the resistivity increases rapidly, which is due to the appearance of donors, which partially compensate for the acceptors, which reduces the concentration of free holes, and, as a result, we have an increase in the resistance. The behavior of the thermopower coefficient α (x, T) Lu1-xScxNiSb is adequate. The appearance and increase in the electron concentration are accompanied by an increase in the thermopower coefficient α (x, T). At a concentration of x ≈ 0.07, the dependence of the thermopower coefficient contains an extremum, and then the values of the thermopower coefficient rapidly decrease at a temperature of T = 80 K and concentrations at x ≈ 0.1. Electrons are already the main current carriers. This is indicated by the negative values of the thermopower coefficient. It was experimentally established that at the concentration range x = 0–0.07 the Fermi level velocity εF from the valence band εV is ΔεF/Δx = 4.9 meV /% Sc, and at the concentration, x ≥ 0.07 – ΔεF/Δx = 11.2 meV /% Sc. The presence of a difference in the velocities of the Fermi level εF indicates different rates of generation of acceptors and donors: at a concentration of x ≥ 0.07, the concentration of donors increases ~2 times faster than at the site x = 0–0.07. The functions of conversion of sensitive elements of resistance thermometer and thermoelectric transducers in the temperature range 4.2–1000 K are modeled. The ratio of the change in the values of the thermopower coefficient to the range of temperature measurements in thermocouples is greater than all known industrial thermocouples. In addition, the temperature coefficient of resistance (TCR) of the obtained resistance thermometers is higher than the TCR of metals but is inferior to the value of TCR of sensitive elements made of traditional semiconductors. At the same time, none of the known resistance thermometers based on traditional semiconductors provides stable characteristics at temperatures of 4.2÷1000 K.Item Bit operations with elements of the RSA algorithm in encryption-decryption of color images(Видавництво Львівської політехніки, 2022-02-28) Kovalchuk, Anatoliy; Peleckh, Yuriy; Bubela, Tetiana; Lviv Polytechnic National UniversityAn image as a stochastic signal is one of the most common forms of information. Protecting images from unauthorized access and applying is a correspondingly urgent task. This causes the use of well-known classical encryption methods in the case of image encryption. But the image is a signal that possesses, in addition to typical informativeness, also visual informativeness. Informativeness for modern image processing methods makes it possible to ensure unauthorized access. Creating an attack on an encrypted image is possible in two ways: by traditional hacking of encryption methods, or by classical methods of visual image processing (filtering, highlighting contours, etc.). In this regard, one more requirement is put forward to encryption methods in the case of their application concerning images – this is the complete noise of the encrypted image. This is necessary so that the use of visual image processing methods becomes impossible. The RSA algorithm is one of the most widely known industrial standards for encrypting signals. Unlike symmetric encryption, in an open-key encryption scheme, it is impossible to calculate the decryption procedure, knowing the encryption procedure. Namely, the working time of the algorithm for calculating the decryption procedure is so great that it cannot be implemented on any modern computers, as well as on computers of the future. Such coding schemes are called asymmetric. Therefore, the urgent task is to implement the application of the RSA algorithm so that when encrypting an image: – the cryptographic stability of the RSA algorithm has not become worse; – the full image noise was achieved to prevent the use of visual image processing techniques. The algorithm of elements of the RSA algorithm, as the most resistant to unauthorized decryption of signals, and bitwise operations for a compatible combination during encryption and decryption of images is proposed by the authors. Encryption – decryption is performed without additional noise. The proposed algorithm is applied to images in which there are strictly extracted contours. Elements of the RSA algorithm are assigned to perform bitwise operations on the intensity values of pixels of a color image. The developed algorithm has higher cryptographic stability compared to the traditional RSA algorithm. The authors described the possibilities of using elements of the RSA algorithm in bitwise transformations when encrypting and decrypting images. The results of encryption simulation for cryptographic transformations of color images of a given dimension are presented. Modified models and algorithmic procedures of key formation processes of direct and inverse cryptographic transformations have been developed. They are reduced to elemental mathematical operations.Item RSA algorithm in fractional-rational n-ary forms while encryption-decryption of monochrome images(Видавництво Львівської політехніки, 2022-02-28) Kovalchuk, Anatoliy; Kustra, Nataliia; Yatsyshyn, Svyatoslav; Lviv Polytechnic National UniversityThe basis for image protection is the assumption that the image is a stochastic signal. But the image is a specific signal that possesses, in addition to typical informativeness (informativeness of data), also visual informativeness, which brings new challenges to the issue of protection. Therefore, the urgent task is to implement such application of the RSA algorithm that when encrypting an image: the cryptographic stability of the RSA algorithm did not deteriorate; achieves full image noise to prevent the use of visual image processing methods. An algorithm for encryption-decryption of monochrome images in fractional-rational forms of order n using the elements of the RSA algorithm is proposed, as the most resistant to unauthorized decryption of signals. The proposed algorithm is applied to images with strictly separated contours. Elements of the RSA algorithm are applied to construct the coefficients of fractional-rational affine transformations. The developed algorithm is inherent in the higher cryptographic stability compared to the ordinary RSA algorithm. The possibilities of using the elements of the RSA algorithm in affine transformations while encrypting and decrypting images are described. The results of encryption modeling for cryptographic transformations of monochrome images of a given dimension are given. Modified models and algorithmic procedures of key formation processes, direct and inverse cryptographic transformations, reduced to mathematical element-by-element operations, have been developed.Item Титульний аркуш до “Вимірювальна техніка та метрологія”(Видавництво Львівської політехніки, 2022-02-28)