Факультет Комп'ютерних технологій і систем (ДІІТ)

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ENG: Faculty of Computer Technologies and Systems

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Abnormal Effect of Changing the Wetting Angle in Non-Equilibrium Melt–Solid Metal Systems
(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, Kyiv, 2024) Shtapenko, Eduard Ph.; Syrovatko, Yuliya V.
ENG: The paper deals with the temperature dependence of the contact angle of wetting of a steel substrate with a liquid tin. The experiment shows that the wetting angle is decreased as the temperature rose, and the wettability of this system is improved. However, with the further increase in temperature, the contact angle is increased again that is an abnormal phenomenon. To explain this phenomenon and the process of contact-angle formation in general, we propose the quantum mechanical model based on the Wentzel-Kramers-Brillouin (WKB) conception. In this case, interaction of the melt ions with the substrate atoms is considered indirectly through the formation of a potential barrier with the linear dimensions determined by both the ratio of masses of the atoms of interacting metals and the temperature. From the WKB standpoint, at low temperatures, when the kinetic energy of a generalized particle with the reduced mass is less than the potential barrier, the wave function decays rapidly and, accordingly, the contact angle does not actually change. Quantitative and qualitative changes appear, when the kinetic energy of particles with the reduced mass exceeds the positive barrier values because of increase in temperature. Following the WKB conception, passage or reflection of a particle with the reduced mass over the barrier is determined by the integer or half-integer ratio of the de Broglie wavelength and linear dimensions of the potential barrier. Therefore, qualitative changes in the system, i.e., the wetting threshold and abnormal increase in the contact angle, are described by the processes associated with passage or reflection of a particle with the reduced mass over the barrier. Experimental and theoretical curves of dependences of both the contact angle and the work of adhesion versus temperature show similar dynamics.
About Electromagnetic Compatibility of Track Circuits with the Traction Supply System of Railway
(Institute of Electrical and Electronics Engineers, IEEE, 2018) Serdiuk, Tetiana M.; Feliziani, Mauro; Serdiuk, Kseniia
ENG: Track circuits are of fundamental importance for the safety in railway systems. Thus, they must be immune from electromagnetic interference (EMI). To this aim they must be accurately characterized. The paper deals with the determination of spectrum composition of traction current with the electric traction. A method of measuring the parameters of track circuits (time and amplitude parameters of code current, flowing in rail lines, an input impedance of a track circuit, characteristic impedance and propagation constant) is considered Automated method of measurement of parameters of track circuits and harmonics of return traction current was elaborated by the car-laboratory. The harmonics coinciding with the code frequency are inadmissible for the track circuits.
About Optimizing of Investments Volume to Improve the Basic Indicators of the Enterprise Effectiveness
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2015) Gasanov, Zakariia M.
EN: Purpose. Profit and profitability of any, including transport enterprises are the main economic indicators of the enterprise effectiveness. These indicators reflect the results and successful performance of the enterprise. On the other hand the enterprise effectiveness in the long term, assurance of rapid development and competitiveness is largely determined by the level of investment activity and the range of investment activity. The purpose of this study is the feasibility of the method to determine optimal investments volume for improving these or others (selectable by the management) principal economic indicators of the enterprise effectiveness. Methodology. The basis of the proposed methodology for determining the optimal investments volume is the theory of optimal control, in particular, the procedure of dynamic programming since a managed development process of the enterprise is a multiple stage. This procedure, using a phased plan, allows not only simplifying the solution of optimization problems, but also solving those, which are impossible to apply the methods of mathematical analysis. Findings. The expediency of performing the calculations to determine the optimal investments volume to ensure high rates of enterprise development was proved, it is a key to the effectiveness of the enterprise in the long term and it improves its competitiveness. Originality. It is shown that using methods of the optimum control theory one can calculate the minimum volume of capital investments for the improvement of economic indicators, which determine the enterprise effectiveness. The proposed method of calculation does not depend on the specific content of economic indicators. The effectiveness of this calculation method is demonstrated on a model example. Practical value. The proposed method of calculating the minimum volume of capital investments to improve the economic effectiveness of enterprises is quite simple, but at the same time enables, on the one hand, to determine priority directions of investment activity of the enterprise. On the other hand it improves the manageability and transparency of business enterprises, increases the head's confidence in the correctness of decisions.
About Track Circuit Calculation Method Dependent on Ferromagnet Properties in Conditions of Traction Current Noise Influence
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2016) Zhuravlov, Anton Yu.
EN: Purpose. The work is intended to investigate the electromagnetic processes in impedance bond in order to improve noise immunity of track circuits (TC) for safe railway operation. Methodology. To achieve this purpose the methods of scientific analysis, mathematical modelling, experimental study, a large-scale simulation were used. Findings. The work examined the interference affecting the normal performance of track circuits. To a large extent, part of track circuit damages account for failures in track circuit equipment. Track circuit equipment is connected directly to the track line susceptible to traction current interference, which causes changes in its electrical characteristics and electromagnetic properties. Normal operability, performance of the main operating modes of the track circuit is determined by previous calculation of its performance and compilation of regulatory tables. The classical method for determination of track circuit parameters was analysed. The classical calculation method assumes representation of individual sections of the electrical track circuit using the quadripole network with known coefficients, usually in the A-form. Determining the coefficients of linear element circuit creates no metrological or mathematical difficulties. However, in circuits containing nonlinear ferromagnets (FM), obtaining the coefficients on the entire induction change range in the cores is quite a difficult task because the classical methods of idling (I) and short circuit (SC) are not acceptable. This leads to complicated methods for determining both the module and the arguments of quadripole network coefficients. Instead of the classical method, the work proposed the method for calculating the track circuit dependent on nonlinear properties of ferromagnets. Originality. The article examines a new approach to the calculation of TC taking into account the losses in ferromagnets (FM), without determination of equivalent circuit quadripole network coefficients. When building the FM reversal model in parallel magnetic fields, the most accurate methods are the approximation ones that take into account not only the changes in values and over time, but also their derivatives. The development of computer hardware and software makes real the mathematical methods for calculating TC with significant change in ferromagnetic inductance, including the saturation areas. Herewith, it is important to search for approximating analytical expression that describes the dynamic limit hysteresis loop (HL). Practical value. The changes in the electrical parameters of the same TC were analysed using the classical and the new calculation methods, the difference made less than 10%. The work introduced some measures to increase operational noise immunity of TC.
The Accuracy of Traction Current Harmonics Parameters Determination by Windowed FFT
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2018) Havryliuk, Volodymyr I.
EN: In the work the correct choosing of the windowed FFT parameters to achieve the necessary time and frequency resolution of the traction current spectral analysis in accordance with the re- quirements of regulatory documents has been briefly overviewed and investigations of the influence of FFT parameters on the accuracy of the determination of harmonics parameters (such as effective current, frequency, duration) have been carried out.To assess the accuracy of determining the RMS current and frequency of the harmonics, a computer study was performed using a synthesized current with known harmonics parameters, the values of which were chosen in accordance with the permissible values of the parameters determined by regulatory documents and standards.For the spectral analysis of traction current, four types of windows were selected: rectangular, Hann, Hamming and Blackman windows with duration of 0.3 and 1 s. For a sampling frequency of 27500 Hz and a window length of 0.3 s, the frequency resolution is 0.27 Hz for a rectangular window, 0.54 Hz for Hann and Hamming windows and 0.81 Hz for Blackman's window, which is consistent with the requirements of the specifications.The results of spectral analysis of traction current showed that the frequency resolution of harmonics, and accordingly the relative error in determine the frequency and the RMS value of harmonics is lower for high frequencies in spectrum.The type of windows used has a slight effect on the accuracy of determining the frequency of harmonics. The relative error of the effective value of the harmonic current was higher for a rectangular window, and relative error decreased in the row from the rectangular window to the Blackman window. The values of the relative error of the RMS current for several frequencies ofthe harmonics did not meet the requirements necessary for the practical use of the method, and this is due to spectrum leakage and scalloping.For windows with a length of 1 s, the frequency resolution of the traction current was higher. than for windows with a length of 0.3 s, and the relative error of the RMS current and frequen- cies of the harmonics were much lower, but even in this case, the relative error was high for individual frequencies .To ensure the necessary accuracy of the traction current spectral analysis with using win- dowed FFT, proper choosing of the spectral analysis parameters taking into account the traction current parameters is necessary. Taking into account a wide frequency range of traction current, a technique with variable window length and sampling frequency for different parts of the spectrum is perspective for using.
Advanced Study on Resource-Saving Methods of Forming Information Infrastructure of Sorting Stations
(BP International, West Bengal, India, 2021) Kosolapov, Anatolii A.
EN: This chapter discusses a resource-saving method for choosing a rational structure of an automated control system when technical structure migration from a centralized system based on a powerful processor to a functionally distributed system based on microcontrollers. The method allows you to determine a rational number of subsystems that effectively use the computing and financial resources of the project. The approach is illustrated by a real example of designing an automated control system for a marshalling yard.
Analysis and Research of the Causes and Course of Degradation of Lithium Batteries
(EDP Sciences-Web of conferences, 2024) Buriak, Serhii Yu.; Gololobova, Oksana O.; Havryliuk, Volodymyr I.; Serdiuk, Tetiana M.; Voznyak, Oleh M.; Manachyn, Ivan O.
ENG: Energy storage devices based on lithium technology are confidently leading the respective market due to their significant advantages over other technologies in the industry. Despite their relatively recent history of appearance, they managed to undergo many modifications of both physical and chemical components. One of the constant goals of all research in this field is the formation of knowledge about the degradation processes occurring inside a given chemical current source, and ways to influence them. Systematization and identification of the fundamental reasons for the decrease in the performance of lithium batteries still remains a topical issue of today, and therefore is considered in this article. And no matter how studied this issue looks, taking into account the existing many long-term experimental data of a huge number of scientists and a number of different types of companies, but still, optimization of work is impossible without identifying and eliminating as many destructive factors as possible in battery operation. The difficulty of this process lies also in the fact that, taking into account all the high-tech production processes in the world, there are no two identical lithium current sources. On the example of a single battery, the ability to maintain high performance, close to nominal, was demonstrated from a source that, due to its lifetime, should not have had them. The data obtained during the experiment, which confirmed the high performance, show once again that the issue of degradation of lithium current sources can and should be studied further.
Analysis of Operation of Railway Communication Systems
(Дніпровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2019) Botnarevscaia, R.; Serdiuk, Tetiana M.
ENG: Actuality. Technological progress, which has rapidly burst into our lives, dictates its own rules. There is a need to modernize the railway infrastructure, which, in its current equipment, built in 70-80 years of the last century, is morally and technically obsolete. Considering the huge volumes of work to be done, we come to the understanding that it is not possible to carry out such modernization in a short time, both from a financial point of view and from a technical point of view. For a long time, you will have to measure with the simultaneous operation of both new and old equipment and ensure their uninterrupted functioning. New electronic equipment introduced in various fields requires careful testing for electromagnetic compatibility. Ensuring safety in the transport of passengers and goods depends on this. So, the scientific work deals with the analysis of operation of railway communication systems are actuality. The object of research is railway communication lines. The main purpose is to evaluate the quality of different kinds of railway communication and the reasons of noise and interference in these systems. It was carried out the follows in the paper: the reasons of appearance noises in the telecommunication channels (radio and wire communications) were analyzed; the main faults in the overhead communication lines and their influence on the quality of communication were evaluated; the electromagnetic interferences in the communication lines and their frequency diapasons were researched; the further ways of investigation and simulation of influence traction and non-traction systems on the communication channels were described. The scientific novelty is in the proposition of use CST simulation to investigate electromagnetic influence of traction and non-traction power system on the communication channels with the 8-poles mathematic modelling. Research will be carried out by the method of direct measurements on existing equipment and collection of statistical data. At the end of the research, conclusions will be drawn about the electromagnetic compatibility of the of old and new equipment of communication systems, and we can say that the issue does not lose its relevance due to the introduction of new types of rolling stock, the modernization of traction substations.
Analytic Hierarchy Process Sustainability at the Significant Number of Alternatives Ranking
(CEUR-WS Team, Aachen, Germany, 2020) Shynkarenko, Viktor I.; Vasetska, Tetiana M.; Vyshnyakova, Iryna М.
ENG: This paper focuses on the need to evaluate the sustainability of Analytic hierarchy process at the Ranking of more than 10 alternatives. The proposed method is based on simulation modeling of the process of improving expert pair-wise comparison judgments. The represented method provides a stepwise improvement of the pair-wise comparison matrix transitivity. The average discrepancy and coincidence of ranks in multiple modeling are proposed as estimates of the rating stability. The application of the developed method was studied on a statistical sample formed according to the final tables of the England, Germany and Spain football championships. The method for determining probability of some alternatives ranks is developed. It is possible to modify the method for predicting the results of sports competitions and for the case of ranking with partially missing expert ratings.
ANFIS Based Detecting of Signal Disturbances in Audio Frequency Track Circuits
(IEEE, 2020) Havryliuk, Volodymyr I.
EN: The problem considered in the work is concerned to monitoring of signal disturbances occurred in the audio frequency track circuits (AFTC). Track circuits are designed to detect the presence or absence of a train in a particular section of the rail track, and therefore, they are main and safety critical components of an automatic train control systems. Deterioration of the AFTC components appeared during their operation, as well as electromagnetic interference and adverse weather conditions can significantly change the signal current parameters, which can lead to dangerous situations for train movement. To ensure safety of railway signalling system, it is necessary to use an automatic diagnostic system that allows timely detection of appearance of significant disturbances in AFTC signal. The use for this purpose the classifiers with sharp boundaries for input diagnostic parameters and strict rules for signal classification does not allows to reveal incipient defects that arise in the ALSN system. The work investigates the effectiveness of using adaptive neuro-fuzzy inference system (ANFIS) and wavelet packet energy Shannon entropy (WPESE) for timely detecting of signal disturbances in audio frequency track circuits. The obtained results confirmed the efficiency of AFTC signal processing using ANFIS and WPESE for detecting of railway sections with unstable or faulty track circuits operation.
Application of Constructive Modeling and Process Mining Approaches to the Study of Source Code Development in Software Engineering Courses
(Split: Croatian communications and information society, Croatia, 2021) Shynkarenko, Viktor I.; Zhevaho, Oleksandr O.
ENG: We present an approach of constructing a source code history for a modern code review. Practically, it is supposed to be used in programming training, especially within initial stages. The developed constructor uses constructive-synthesizing modeling tools to classify a source code history by fine-grained changes and to construct an event log file aimed to provide information on students’ coding process. Current research applies Process Mining techniques to the software engineering domain to identify software engineering skills. By better understanding of the way students design programs, we will help novices learn programming. This research provides an innovative method of using code and development process review in teaching programming skills and is aimed to encourage using code review and monitoring coding practice in educational purposes. The standard method of evaluation takes into consideration only a final result, which doesn’t meet modern requirements of teaching programming.
Application of Fourier Transform and Wavelet Decomposition for Decoding the Continuous Automatic Locomotive Signaling Code
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпро, 2017) Hololobova, Oksana O.; Havryliuk, Volodymyr I.
EN: Purpose. The existing system of automatic locomotive signaling (ALS) was developed at the end of the last century. This system uses the principle of a numerical code which is implemented on the basis of relay engineering, and therefore, it is exposed to various types of interferences. Over the years, the system has been upgraded several times, but the causes of faults and failures in its operation are still the subject of research. It is known that the frequency and the phase modulation of signal has a higher interference immunity as compared to the amplitude modulation. Therefore, the purpose of the article is to study the possibility of using the frequency methods such as Fourier series expansion and wavelet decomposition to extract the informational component of the received code from ALS signals under the action of various types of interferences. Methodology. One can extract the information unavailable in time representation of the signal using the signal studies in the frequency domain. The wavelet decomposition has been used for this purpose. This makes it possible to represent the local characteristics of the signal and to provide time-frequency decomposition in two spaces at the same time. Due to the high accuracy of the signal representation it is possible to analyze the time localization of spectral components and eliminate interference components even in the case of coincidence of interference frequency with the signal carrier frequency. Findings. To compare informativity of the methods of Fourier expansion and wavelet decomposition it was studied the reference and noisy signal of green fire code using the software package MATLAB. Detailed analysis of the obtained spectral characteristics showed that the wavelet decomposition provides a more correct decoding of the signal. Originality. Replacing the electromagnetic relays in the ALS system by microprocessor hardware involves the use of some mathematical tool for decoding, in order to obtain more information about the code. More often than not, as a mathematical tool, the classical Fourier decomposition is used. But because of a number of drawbacks in this method, it was suggested to use the wavelet decomposition, which has a number of advantages and accounts the disadvantages of the Fourier transform. Practical value. The presented method of code signal research can be the basis for developing dynamic model of the ALS receiver and decoder using digital processing module, which will enable to increase the reliability and accuracy of extraction of the code information component.
An Approach to Assessing the Operational Reliability of Real-Time Systems at the Stage of Conceptual Design
(ScientificWorld-NetAkhatAV, Karlsruhe, 2023) Belyaev, Nikolai; Kosolapov, Anatoliy; Egorov, Oleh Yo.; Sokur, Maria; Parpolita, Oleksandr M.
ENG: Сurrently, many facilities operate in real-time mode in an environment with a high level of radio-magneto-electronic interference. The software of such systems, debugged in stationary conditions, during the period of pilot operation gives a large number o.
Approximation of Periodic Functions of Many Variables by Functions of a Smaller Number of Variables in Orlicz Metric Spaces
(Springer, 2019) Babich, Yurii P.; Mikhailova, Tetiana F.
EN: For periodic functions of many variables, we propose a method for their approximation in the Orlicz spaces Lφ (T^m). According to this method, the functions are approximated by the sums of functions of smaller number of variables each of which is piecewise-constant in one variable for fixed values of the other variables. A Jackson-type inequality is analyzed for these approximations in terms of the mixed module of continuity.
Artificial Neural Network Based Detection of Neutral Relay Defects
(Dnipro National University of Railway Transport named after Academician V. Lazaryan, 2019) Havryliuk, Volodymyr I.
EN: Abstract. The problem considered in the work is concerned to the automatic detecting and identifying defects in a neutral relay. The special design of electromechanical neutral relays is responsible for the strong asymmetry of its output signal for all possible safety-critical influences, and therefore neutral relays have negligible values of dangerous failures rate. To ensure the safe operation of relay-based train control systems, electromechanical relays should be periodically subjected to routine maintenance, during which their main operating parameters are measured, and the relays are set up in accordance with technical regulations. These measurements are mainly done manually, so they take a lot of time (up to four hours per relay), are expensive, and the results are subjective. In recent years, fault diagnosis methods based on artificial neural networks (ANN) have received considerable attention. The ANN-based classification of relay defects using the time dependence of the transient current in the relay coil during its switching is very promising for practical utilization, but for efficient use of ANN a lot of data is required to train the artificial neural network. To reduce the ANN training time, a pre-processing of the time dependence of relay transient current was proposed using wavelet transform and wavelet energy entropy, which makes it possible to reveal the features of the main defects of the relay armature, contact springs, and magnetic system. The effectiveness of the proposed approach for automatic detecting and identifying of the neutral relays defects was confirmed during testing of the relays with various artificially created defects.
Audio Frequency Track Circuits Monitoring Based on Wavelet Transform and Artificial Neural Network Classifier
(Institute of Electrical and Electronics Engineers, IEEE, 2019) Havryliuk, Volodymyr I.
EN: Abstract. The problem of revealing and identifying of signal disturbances in audio frequency track circuits is considered in the article. Track circuits are a key component of automatic train control system and used to detect whether the rail section is free or occupied. Amplitude-modulated signals used in track circuits have low noise immunity, therefore the power wide-band-frequency interference generated by an electrified railway can cause failure operation of track circuits. To ensure the safety of the track circuits, they are subjected to periodic maintenance with registration of the signal current to the computer and measurements of its parameters. The detection of time intervals during which the interference in the track circuits exceeds certain limit values is performed by simple visual analysis of the recorded signal and is time consuming and expensive. In order to automate the revealing and identification of disturbances in audio frequency track circuits with values exceeding the certain level, a new method for processing the of the recorded signal have been proposed. At the first stage of the proposed method, the segments of a signal with interference exceeding a certain permissible level are revealed using the wavelet packet energy Shannon entropy. At the second stage, for the revealed segment with disturbances, a detailed analysis of the signal should be carried out using the digital wavelet packet transform to determine the type and parameters of the disturbances. For automatic identification of the track circuits signal disturbances, an artificial neural network classifier has been used. As a result of investigation the features of the signal disturbances in audio frequency track circuits have been extracted. The processing of the track circuits signals in accordance with the proposed method show high effectiveness in the revealing and identification of the signal disturbances.
Authorship Determination of Natural Language Texts by Several Classes of Indicators with Customizable Weights
(CEUR-WS Team, Aachen, Germany, 2021) Shynkarenko, Viktor I.; Demidovich, Inna
ENG: In this work we try to improve the results of texts and their fragments attribution using the classification method of the least distance in Euclidean space of images, by selecting weights for each of the image measures. For weights determination the genetic algorithm was used. Images are formed using statistical and modified recurrent analysis and the text complexity indicators. We will try to identify the effectiveness for each of them. It was found that this method usage improves the efficiency of the text attribution and the reliability of authorship determination of the texts from the control sample reaches 80-91%.
Automated Measurement of Parameters of Track Circuits
(Дніпропетровський національний університет залізничного транспорту імені академіка В. Лазаряна, Дніпропетровськ, 2015) Serdiuk, Tetiana M.
EN: The method of measuring the parameters of track circuits (a time and amplitude parameters of code current, flowing in rail lines, an input impedance of the track circuit, a characteristic impedance, a propagation constant) is considered in this paper. The algorithms of definition of parameters of track circuit (ТС) are elaborated. As a result, the develop hardware-software apparatuses allows you to define by the EMF induced in the two receiving coils separately, the following quantities: the magnitude of the code current for the entire length of the track circuit, the duration of the pulses and pauses for all parcels of code, determine the type of code signal and the type of code track transmitter, coordinate, the length of the TC, serviceability of insulating junctions and electrical connectors. The results of measurements of EMF induced in each of the receiving coils apart, the spectral composition of the noise occurring in the traction network, and harmonic amplitude and impulse noise, the causes of noise in the rail network can be revealed. Algorithm for checking the status of the track circuit involves determining the state of the track circuit and it is carried out on the current curve of the locomotive signalling depending on the coordinates obtained from the measurements. Underestimated the value of ALS current compared with the calculated value indicates an undervalued ballast resistance. The test of offered measuring apparatuses were executed on the Pridneprovsky railway.
Automated Monitoring of Content Demand in Distance Learning
(CEUR-WS Team, Aachen, Germany, 2021) Shynkarenko, Viktor I.; Raznosilin, Valentyn V.; Snihur, Yuliia
ENG: In this paper the research of means and the development of software for matching the student’s gaze focus with the structure of information on the computer monitor during distance learning is presented. Widespread hardware is envisaged to be used. Primary processing of the face image, eye regions separation is performed by means of the OpenCV library. An appropriate algorithm to calculate the center of the eye’s pupil has been developed. The influence of the system calibration process with different schemes of calibration point display, its delay time on the screen and location of the additional camera according the accuracy of the calculation the coordinates of the gaze focus is investigated. Based on the performed experiments, it was defined that the error of gaze focus recognition with using two cameras can be reduced to 4-10%. The proposed approach makes it possible for objective measurement the working time of each student with one or another part of content. The lecturer will have the opportunity to improve the content by highlighting significant parts that receive little attention and simplifying those elements that students process for an unreasonable amount of time. It is planned to integrate the developed software with the LMS Moodle in the future.
Automatic Method for Monitoring the Lower Ionosphere and Lightning Location by Tweek-Atmospherics
(Університет прикладних наук Інхолланд, Голландія, 2018) Shvets, Аleksandr V.; Krivonos, Alexey P.; Serdiuk, Tetiana M.; Hayakawa, M.
ENG: A new real-time technique is proposed for automatic identification of tweek atmospherics, distance finding to lightning and estimating the effective heights of the lower ionosphere for the fundamental and higher order modes of the Earth-ionosphere waveguide. Effectiveness of the technique is demonstrated with the experimental records of atmospherics. Application of a clustering algorithm allowed us to reveal different patterns of variations of the lower ionosphere effective height along different propagations paths. The distance finding accuracy of our tweek method had been roughly estimated by a comparison with independent data from the Blitzortung.org lightning location network to be less than 100 km with standard deviation less than 200 km in the range of distances from 500 to 1400 km.

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