Showing papers by "Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan published in 2019"
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TL;DR: In this article, social expectations of personality are considered as philosophical and psychological dimensions of the study, presented by analysing expectations in social constructivism, externalizing, building a model of the expected future.
Abstract: Purpose. To analyse the philosophical and psychological contexts of social expectations of personality, to form general scientific provisions, to reveal the properties, patterns of formation, development and functioning of social expectations as a process, result of reflection and construction of social reality. Theoretical basis of the study is based on the phenomenology of E. Husserl, the social constructivism philosophy of L. S. Vygotskiy, P. Berger, T. Luckmann, K. J. Gergen, ideas of constructive alternativeism of G. Kelly, psychology of social expectations of a personality as the unity of the mental process, mental state and properties of expectations. Originality. Social expectations of personality are considered as philosophical and psychological dimensions of the study, presented by analysing expectations in social constructivism, externalizing, building a model of the expected future. The authors clarified some theoretical and methodological aspects of the study of patterns of social expectations in the reflection and construction of social reality. The role of social institutions in the formation of expectations is outlined. The poly-aspect of the investigated problems is shown. It is substantiated that formation, realization of social expectations in organization of interaction of personality and social environment is possible in the presence of subject, object and content of activity. Conclusions. Social expectations influence social behaviour and determine the behaviour of an individual, small contact group, community, or large mass of people. Social expectations are able to set specific requirements, norms, sanctions, ideals that participants of the process must follow or must not violate. The philosophical dimension of the study integrates the ontological, epistemological, axiological preconditions for the formation and realization of the social ideal, represented by the study of the expected future in the forms of utopia, eschatology and thanatology. Psychological dimension of the study has a sufficiently developed content orientation from the psychological content parameters of social expectations to the role of expectations in social institutions and various spheres of human life. Systematic, actionable, self-regulatory, and subjective approaches have constituted a verified system of interpreting the social expectations of personality as a process, a result of the reflection and construction of social reality. The topic of social expectations of personality is far from being completed, in our opinion it is promising to create a deeper philosophical concept of social expectations of the personality. The specific topics are of particular relevance in the context of socio-political uncertainty, domination of the mass consciousness, loss of national and cultural identity.
24 citations
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TL;DR: In this paper, the authors developed a model for predicting and assessing the efficiency of railway transport from the border of one state to border of the other one, taking into account all expendit...
Abstract: The authors developed a model for predicting and assessing the efficiency of railway transport from the border of one state to the border of the other one, taking into account all expendit...
16 citations
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TL;DR: The main objective of the research was to establish a chronology of events leading up to and including the discovery of the remains of Tournaisia, which were found to be related to the Chernobyl disaster.
Abstract: D. Kozachenko: ORCID 0000-0003-2611-1350; V. Skalozub: ORCID 0000-0002-1941-4751; Yu. Hermaniuk: ORCID 0000-0002-4905-8313; R. Korobiova: ORCID 0000-0002-6424-1079; A. Gorbova: ORCID -0000-0002-5612-2715
16 citations
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01 Dec 2019TL;DR: A model based on the dynamical theory of elasticity allows determining complete spatial-temporal account of the deflection dynamics of the rail support, which enables the execution of calculations, including for conditions of fast-speed and high-speed trains.
Abstract: The authors developed a model based on the dynamical theory of elasticity, which allows us to describe the dynamic equilibrium of strains of the railway track layers. The model of the stress-strain state for the railway track consists in a combination of the geometry equations of the outline of a part in the system's space, involved into interaction at a given time and the equations of the dynamic equilibrium of its deformation. Considering the obligation to register the course of the process in time, for each time step of integration the outline of the strains propagations front is determined. The strains propagations front is described by the equations of propagation in the material of the elastic spatial wave of oscillations. It allows determining complete spatial-temporal account of the deflection dynamics of the rail support, which enables the execution of calculations, including for conditions of fast-speed and high-speed trains. With the application of the developed model, a number of scientific and practical problems were solved.
13 citations
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TL;DR: In this article, the authors assess the current state of digital library publishing (DLP) in university libraries in the Ukraine using a mixed methods approach, involving semi-structured interviews and an online questionnaire.
Abstract: Objective – The objective of this study was to assess the current state of digital library publishing (DLP) in university libraries in the Ukraine. The study was conducted in the hopes of gaining a better understanding of the DLP landscape, namely institutional operations, as well as their varying publishing initiatives, processes, and scope.
Methods – The current study was conducted from January to June 2017 using a mixed methods approach, involving semi-structured interviews and an online questionnaire. Semi-structured interviews were conducted (n = 11) to gain insight into participants’ experiences with DLP. The interviews helped in the creation of the questions included in our online questionnaire. The questionnaire was distributed to 195 representatives (directors and leading specialists) of university libraries in the Ukraine. Replies were received from 111 of those institutions. The questionnaire consisted of 11 open- and closed-ended questions to allow the researchers to obtain a holistic picture of the process under investigation.
Results – Analysis of the 111 questionnaires showed that for 26 libraries, DLP services were performed by employees of a separate structural unit of the library. For 34 libraries, employees of various departments were involved in performing certain types of services. The other 40 respondents’ libraries were planning to do this in the near future. Only 11 respondents replied that they did provide DLP services now nor planned to in the future. Among the libraries providing DLP services, the following results were observed: 54 of 60 work with digital repositories, 47 provide digital publishing platforms for journals, 26 provide digital publishing platforms for books, and 23 provide digital publishing platforms for conferences.
Conclusions – The results obtained indicate a growing trend of expanding digital services in university libraries to support study, teaching, and research. Despite the still spontaneous, chaotic, and poorly explored nature of the development of the library publishing movement in the university libraries of the Ukraine, the readiness of librarians to implement publishing activities is notable. At the same time, the survey results point to specific aspects, such as organizational, economic, personnel, and motivational, that require further study.
11 citations
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01 Oct 2019
TL;DR: The article presents the calculation of the transfer function of the DCM-30-N1-0.2 micromotor DC, obtained a transcendental system of equations for determining the duration of the quasi-optimal control intervals and the dependence of the first control interval on the specified overshoot.
Abstract: The article presents the calculation of the transfer function of the DCM-30-N1-0.2 micromotor DC, obtained a transcendental system of equations for determining the duration of the quasi-optimal control intervals and the dependence of the first control interval on the specified overshoot. The obtained dependence can be used in the engineering methodology for the synthesis of quasi-optimal control and the choice of actuators of the automatic control system.
11 citations
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TL;DR: The practical significance of the obtained results is the use of such a calculation method that does not require significant time for its implementation and can be used as a subsystem of the on-board train control system capable of performing calculations taking into account changes in the current train situation.
Abstract: Development of a method for calculating the optimal mode of conducting a train in terms of energy saving meet the safety requirements and schedules. The method of calculation must solve the assigned tasks without significant time spent on the calculation. To implement this method of calculation was used a simplified model of the train as a controlled system. The existing mathematical and algorithmic methods for solving isoperimetric problems of finding the optimal solution in the presence of restrictions on resources were the information base for methodology development. Scientific works of domestic and foreign scientists, professional periodicals, materials of scientific and practical conferences, methodical and normative materials, currently in force on Ukrainian Railways. The results of these studies were used to create simulators on the basis of computer technology for the training of locomotive drivers. The scientific novelty of the proposed calculation method consists in applying the simplified calculations of the status of the train as a controlled system, without the use of differential equations of motion that allows to significantly increase the speed of the calculations. This, in turn, will solve the problems of finding optimal control in real time, taking into account changing conditions during the movement of the train. The practical significance of the obtained results is the use of such a calculation method that does not require significant time for its implementation and can be used as a subsystem of the on-board train control system capable of per-forming calculations taking into account changes in the current train situation.
8 citations
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01 Sep 2019TL;DR: An artificial neural network was used to classify ALSN signal disturbances, and the efficiency of the proposed algorithm was verified by processing of several specially simulated as well as real ALSN signals measured during tests.
Abstract: The problem considered in the work is concerned to the methods to reveal and identify the signal disturbances occurred in the railway cab signaling system caused by electromagnetic interference from traction current. The continuous automatic locomotive signalling system (ALSN) is a type of cab signalling systems that provides track status information to the train cab and uses the rails as a continuous communication channel between track and train. To ensure the reliability of the transmission of ALSN commands to the train cab, the basic parameters of the coded current are periodically checked for compliance with certain requirements during planned test trips of a specially equipped railway car-laboratory. The ALSN signal is received by the coils of the car-laboratory and recorded by computer. Then an operator visually analyzes the recorded signal to detect problem segments with interference exceeding the limit level what requires a lot of time and does not provide the necessary accuracy. To automate the detection and identification of the ALSN signal disturbances, the following algorithm has been proposed. At the first stage, the wavelet packet energy Shannon entropy is used to reveal problem segments of ALSN signal. At the second stage, a detailed analysis of the ALSN signal using DWPT is performed to determine the type and parameters of interference at the revealed problem segments. To classify ALSN signal disturbances, an artificial neural network was used. The efficiency of the proposed algorithm was verified by processing of several specially simulated as well as real ALSN signals measured during tests.
8 citations
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01 Mar 2019-Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport
TL;DR: The article analyzes the dynamic qualities of a rolling stock using the example of gondola cars, taking into account the possible movement speed increase on the dynamic loading in order to solve the problem of forecasting the rolling stock dynamics.
Abstract: Purpose . Increasing the maximum loading from the car axle on the rails during transportation of goods and the speed of movement of railway vehicles will enhance the integration processes between the countries. In order to ensure safe and reliable traffic at the railways it is necessary to improve control, quantitative evaluation of the dynamic loading of the rolling stock, which in the process of its operation is a relevant scientific and technical problem. The purpose of this work is to study the influence of the axle loading increase in gondola cars, taking into account the possible speed increase on their main dynamic indicators and indicators of interaction of rolling stock and track. Methodology . The study was carried out by the method of mathematical and computer simulation of the dynamic loading of a gondola car using the model of spatial oscillations of the coupling of five cars and the software complex developed in the branch research laboratory of the dynamics and strength of rolling stock (BRL DSRS). The initial data for research are as follows: the movement of gondola car of the model 12-532 with typical bogies of 18-100 at the speeds ranging from 50 to 90 km/h in curves with radii of 350 and 600 m, with superelevation of 130 and 120 mm, respectively. Findings . The article analyzes the dynamic qualities of a rolling stock using the example of gondola cars, the calculations are performed using the package of applied programs with sufficient accuracy for practice. During the theoretical studies and simulation, taking into account the processes of freight car oscillation in case of increasing the axle loading, the dependences of the main dynamic parameters, taking into account the movement speed were obtained. Originality . Originality of the work results lies in the study of the influence of increasing the axle loading in gondola cars, taking into account the possible movement speed increase on the dynamic loading in order to solve the problem of forecasting the rolling stock dynamics. The results of theoretical studies, taking into account the movement speed in the curved track sections of small and medium radius were obtained for the first time. Practical value . The application of these results will contribute to improving the traffic safety of freight cars and will improve the technical and economic performance of railway transport.
8 citations
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01 Jul 2019TL;DR: 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.
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 of the recorded signal have been proposed. At the first stage, 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.
8 citations
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01 Apr 2019
TL;DR: A program has been developed that implements prediction algorithms using neural networks, as well as optimizing the reactive power mode, to reduce electric power consumption, and losses in electrical networks.
Abstract: The high cost of electric power, as well as the considerable length and branching of electrical networks, necessitate reduce electric power consumption, and losses in electrical networks. One of solutions of this problem is optimizing the reactive power mode. Reducing the reactive power factor at the point of common coupling (PCC) to the economic level established by the power system is not taking into account that in a complex network, power flows with a non-optimal arrangement of compensating devices and improper determination of their power can reach large values, that resulting in an increase in losses in the network. A program has been developed that implements prediction algorithms using neural networks, as well as optimizing the reactive power mode.
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05 Sep 2019-Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport
TL;DR: In this article, the influence of non-symmetrical loading of a flat car on the magnitude of the wear factor of a wheel-rail pair when changing the operation parameters that occur in operation is investigated.
Abstract: Purpose . The paper is aimed at determining the influence of non-symmetrical loading of a flat car on the magnitude of the wear factor of a wheel-rail pair when changing the operation parameters that occur in operation. Methodology . The dynamic loading of the flat car, model 13-401 with typical three-piece bogies is studied using a model of spatial oscillations of a five-car coupling with the help of mathematical and computer simulation. Theoretical calculations are performed for the most dangerous sections of the railway track – small and medium radius curves in the range of permissible speeds. Findings . The indicators of wear of the rolling stock wheels and the rails are analysed on the example of flat cars in the presence of a longitudinal and transverse displacement of the load mass centre relative to the car symmetry centre. To obtain information on the effect of permissible deviations of the arrangement of cargo in the car on the magnitude of the dynamic loading of the wheel-rail contact, the authors performed theoretical studies of the spatial variations of the rail carriage and its interaction with the track. Originality . To determine the wear of the wheel-rail pair, the effect of displacement in two directions from the central axis of symmetry of the load gravity centre was studied, taking into account the value of the travel speed along the curved sections of the small and medium radius using a mathematical model of coupling of five freight cars. Practical value . As a result of the theoretical studies carried out, the authors assessed such factors as wear factor, directional force, and hunting of the wheel set of freight rolling stock in the event of load gravity centre displacement when moving along curved sections of the railway track. To establish the possible cause of intensive wear of the wheels and rails, the following parameters were analysed: lozenging of front bogie side frames; hunting of the left side frame of the front bogie; mutual longitudinal movement of the side frame and axle box of the front wheel set; mutual hunting of the left side frame of the bogie relative to the front wheel set.
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01 Sep 2019TL;DR: The extension for Visual Studio, which monitors the process of programming, is developed and the teacher gets an opportunity of visual monitoring of the program development process, which means the active participation in the formation of an effective student programming style.
Abstract: The aim of this paper is to improve the process of program development using high-level languages. The practical application in programming training is expected, especially at early stages. The teacher gets an opportunity of visual monitoring of the program development process, which means the active participation in the formation of an effective student programming style. The extension for Visual Studio, which monitors the process of programming, is developed.
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01 Sep 2019
TL;DR: The improved mathematical model of traction supply net allows us to estimate the propagation of harmonics and traction return current along the feeder zone with different kind of power supply system.
Abstract: An investigation of propagation of return traction current harmonics in rail lines was carried out for railway sections with d. c. and a. c. traction. A mathematic model of traction supply net was proposed. The improved mathematical model of traction supply net allows us to estimate the propagation of harmonics and traction return current along the feeder zone with different kind of power supply system. The impedance of a power network was determined for low frequency interferences of return traction current. Also this paper deals with the determination of spectrum composition of traction current and most dangerous harmonics for track circuits.
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01 Jun 2019TL;DR: A mathematical model based on stochastic optimization allows to find a balance between the expenses for movement of train traffic flows from different railway lines to their terminal reference station and the expenses of a consignee, subject to the limitations of the technological logistics chain in cargo transportation.
Abstract: Abstract The article proposes a method for determining the rational motion intensity of specific train traffic flows on railway transport corridors with account for balance of expenses on traction resources and cargo owners. A mathematical model based on stochastic optimization is developed, which allows to optimize, in the conditions of risks, the interval between trailing trains on the railway lines taking into account the limited resources of the traction rolling stock, the capacity of the stations and freight fronts at the cargo destination point. Solving this mathematical model allows to find a balance between the expenses for movement of train traffic flows from different railway lines to their terminal reference station and the expenses of a consignee, subject to the limitations of the technological logistics chain in cargo transportation. For the solution of this mathematical model, a Real-coded Genetic Algorithm (RGA) was used.
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10 Jan 2019-Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport
TL;DR: According to the developed model of situation development for the case of a critical defect it is possible to determine the critical level of the defect of the freight car unit taking into account the human factor to limit the risk of an accident or transport event.
Abstract: Purpose. The scientific work is aimed to: 1) study the indicators and criteria for evaluating the influence of human factor on failure-free operation of freight cars; 2) theoretically describe the probabilistic model of the human factor role during the maintenance and repair of freight cars according to technical state; 3) consider the model of situation development for the case of a critical defect of the freight car unit taking into account the human factor. Methodology. In order to achieve this purpose, the methodological approaches were considered: 1) to evaluation of the reliability indicators in the system «man – freight car» during maintenance and repair; 2) to evaluation of the level of traffic safety in case of transition from the existing system of maintenance and repair of freight cars to the system according to technical state. The model of the situation development for the case of a critical defect of the freight car unit with the consideration of the human factor was described. Findings . The approach to the evaluation of risk indicators of potential failures of freight cars is given. The probability of occurrence of negative events (risks) and possible economic damage from their manifestation were taken as the indicators. In the developed model of situation development for the case of a critical defect of the freight car unit with the consideration of the human factor, three possible states are shown: workable and limited workable, unworkable and emergency. Each initial state is characterized by the development of events, which is associated with designers` errors, with defects during manufacture of parts and units, with human factor. Originality . It is proposed to consider the value of the failure probability, which is related to the human factor, as a certain proportion of the overall probability of failure of the system «man – freight car». The interpretation of Harrington's desirability function for the case of application to freight cars is given. During maintenance and repair, it is suggested to introduce an indicator that characterizes the observance of the technology of use of maintenance services for freight cars, taking into account the human factor. Practical value . Based on the conducted research it is possible to evaluate the influence of the human factor on the maintenance and repair of freight cars. According to the developed model of situation development for the case of a critical defect it is possible to determine the critical level of the defect of the freight car unit taking into account the human factor to limit the risk of an accident or transport event.
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11 Sep 2019TL;DR: Using the tools of structural-synthesizing modeling, a set of constructors was developed that can be the basis for solving the dynamic problems on lightning protection of engineering constructions and civil objects, and development of strategy of aircraft behavior in order to mitigate the risks of lightning strokes in the conditions of movement in the thunderstorm front.
Abstract: Using the tools of structural-synthesizing modeling, a set of constructors was developed. Implementing parametric multi-character constructors allows to form fractal sequences of characters. Constructor-converter from the character string to time series creates fractal time series, which determine the location, magnitude and decay rate of lightning discharges. Model video images of lightnings in the thunderstorm front are formed in accordance with the implementation of the constructor-assembler. All constructors are developed on the basis of the generalized constructor that was previously presented and repeatedly tested. The model adequacy of the model is confirmed by comparing the video image of the model with the image, what was obtained by NASA satellite. This approach can be the basis for solving the dynamic problems on lightning protection of engineering constructions and civil objects, and development of strategy of aircraft behavior in order to mitigate the risks of lightning strokes in the conditions of movement in the thunderstorm front.
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30 May 2019TL;DR: The subjectivity of feminist interpretation is not a transparent line between the human being and the surrounding world: the "better" is interpretation, the more "objective" seem our narratives, the stronger appear constructs stipulated by culture, gender, ideology as discussed by the authors.
Abstract: Interpretation as a stream of our consciousness is determined by different contexts and various narratives which stimulate this process reacting to the changeability of the world and human beings in it. The postmodern theory while losing its topicality keeps the key principle of interpretation firm and stable. Interpretation is simultaneously open and fixed, though the process of constructing narratives is not. As interpretation provides vast space for gender, the feminist theory proceeds with the «new feminist reading», and the aim of the feminist criticism lies in revealing misogynism and masculine approaches to different discourses and narratives. Still in postmodernism feminist interpretation often rejects «comprehension» in its classical meaning denying analogy, symmetry and equivalence. The subjectivity of feminist interpretation is not a transparent line between the human being and the surrounding world: the «better» is interpretation, the more «objective» seem our narratives, the stronger appear constructs stipulated by culture, gender, ideology.
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01 Sep 2019TL;DR: The proposed S-models allow automation and visualization of the motion dynamics study for test-bench components in order to determine their rational elastic-weight, kinematic and dynamic behavior.
Abstract: Wheelset axles are essential parts of railway and mine site rolling stock. For fatigue testing of axles, various test-benches are designed to implement the cyclic loads. The effectiveness of test-bench vibration analysis grows with the use of numerical approach and simulation models created with the aid of visual programming tools. The purpose of the work is to develop and assess the proposed simulation models of test-bench dynamics created with the aid of visual programming tools. Based on mathematical models, the test-bench simulation models of the lever system vibration have been developed. Simulation models are created with the aid of Simulink visual programming tools running under Matlab system. For modelling the components of Simulink, the SimMechanics and DSP System Toolbox Libraries are used. The comparative analysis of proposed models has been made. For the first time, with the aid of Simulink visual programming tools, the set of test-bench vibration simulation models has been obtained in steady-state and transient motion modes for linear task formulation. The proposed S-models allow automation and visualization of the motion dynamics study for test-bench components in order to determine their rational elastic-weight, kinematic and dynamic behavior. Simulation of vibrations was carried out using design parameters of the test-bench metal framework.
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21 Mar 2019-Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport
TL;DR: It is proved that the application of the increased level of abstraction using specialized PHP-frameworks and ORM instead of pure SQL allows the developer to focus on the development of a rather complex and at the same time a simple system from the point of view of development.
Abstract: І. Kliushnyk: ORCID 0000-0001-9939-0755, T. Kolesnykova: ORCID 0000-0002-4603-4375, О. Shapoval: ORCID 0000-0002-2568-036X
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23 Sep 2019-Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport
TL;DR: Biliaiev et al. as discussed by the authors reported ORCID 0000-0002-1531-7882; T.M. Rusakova and T.E. Bondarenko: Orcid 0000-0003-4717-3032; E. Gunko and E. Masevitch: ORcID0000-0001-9257-763X
Abstract: M. Biliaiev: ORCID 0000-0002-1531-7882; T. Rusakova: ORCID 0000-0001-5526-3578; I. Kalashnikov: ORCID 0000-0002-2814-380X; I. Bondarenko: ORCID 0000-0003-4717-3032; E. Gunko: ORCID 0000-0001-9257-763X
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16 Dec 2019TL;DR: In this paper, the authors analyze the experience of university libraries in different countries in working with the Open Textbook (OT) and to consider the prospects of creating a similar pilot project in Ukraine.
Abstract: Objective . The study aims to analyse the experience of university libraries in different countries in working with the Open Textbook (OT) and to consider the prospects of creating a similar pilot project in Ukraine. Methods . The analysis covered the world publications (journals, books, conference proceedings, posts on social networks) in the field of Library and Information Science, devoted to the role of libraries in OT support, that have appeared since 2014. The author studied the aspects revealing that publication, namely OT, support services are areas with great potential for the future development of academic / university libraries. Results . Numerous evidence is presented that the topic of library as a publisher in OT support is most developed in the universities and colleges in economically developed countries, especially in the USA, Canada, Australia, and Great Britain. Library strategies for OT projects have been identified. The author clarified the nature of the initiatives and partnerships of libraries in supporting OT, as well as the basic services and roles of libraries in these projects. Conclusions . Today, the global practice of Scholarly Communication has enough evidence that the functions of the Library, lost in the course of evolution, as a Knowledge Publisher have returned under its “roof” and supplemented the existing function of Knowledge Managers. Digital Library Publishing (DLP) services in OT support help to change the learning environment and life of students (including persons with disabilities), pedagogical practices of teachers by means of free textbooks with an open license, as well as to receive reputation benefits for the university, improving the image of the latter. The possibility of eliminating systemic inequalities in access to academic resources increases the significance and changes the role of libraries in open education. The successes of Ukrainian librarians in supporting digital scholarly communication initiatives and the successful implementation of Open Access support projects (repositories, e-journals, e-conferences) give confidence that they can act as initiators and key partners in creating affordable textbooks.
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01 Jul 2019TL;DR: To prompt detection of all possible armature defects, to use the wavelet Shannon entropy as an integral parameter, the value of which strongly depends on the appearance of any order disturbances in the systems was proposed in the work and results confirmed their effectiveness.
Abstract: The article deals with the problem of automatic detection defects of armature and contact springs in railway signalling relays. Signalling relays are currently basic components in train control systems that ensure train traffic safety and to ensure their reliable operation, the relays are periodically subjected to routine maintenance. Most of the tests for signalling relays are performed manually, which is time consuming and very expensive. For developing the automatic method for detecting and identifying the relay armature defects the investigations were performed with ten different types of neutral signalling relays. For each type of relay, several groups were formed, which consisted of three relays, in which one group contained fully serviceable and properly configured relays, while the other groups contained relays with some artificially created defects in the form of deformed contact springs or defects in the coil or magnetic core. To identify the features of the basic defects of relays, the time dependence of the transient currents were measured during relay switching on and off. Three segments are clearly distinguishable on the transient current curve: the first segment when the anchor is in the initial position and the magnetic circuit is open, the second one when the armature moves from the initial to the final position, and the third one when the anchor is picked up and the magnetic circuit is closed. In the first and third segments the current in the relay coil increases exponentially with time constants depending only on the impedances of the coil, which allows to use these time constants for detecting defects in the relay coil and magnetic circuit. In the second segment the current in the relay coil is determined by electromechanical processes that occur during the movement of the armature, which include magnetic, friction, deformation forces etc., and defects of moving components lead to a change in the shape of transient current curve and to appearance of some features in the form of sags and swells on it. Du to these features are small, using the wavelet decomposition of the transient current dependences for detecting defects of armature in signalling relays was proposed in the work. For prompt detection of all possible armature defects, to use the wavelet Shannon entropy as an integral parameter, the value of which strongly depends on the appearance of any order disturbances in the systems was also proposed in the work. The effectiveness of the proposed methods have been investigated and obtained results confirmed their effectiveness.
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01 Apr 2019TL;DR: During the experiment, the energy quality improved when the parallel mode was used, and the concept of smart grid has been proposed to reduce energy losses for dynamic power management.
Abstract: The article is devoted to the experiment, what was performed on the local distribution networks with poor power quality. As a rule, these networks are subsystem of AC traction power supply system, and their design causes voltage unbalance and other power quality problems in consumers. Often, the network is powered by transformers with different vector groups, therefore their parallel operation is impossible. The purpose of the experiment is to assess the effect on energy quality of a regime with sources on both sides. The quality of electrical energy was estimated, considerable attention is devoted to unbalance voltage. Using the statistics methods measurement data are studied. During the experiment, the energy quality improved when the parallel mode was used. The concept of smart grid has been proposed to reduce energy losses for dynamic power management.
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01 Aug 2019••
01 Apr 2019
TL;DR: It is suggested that the instantaneous reactive power should be used for the analysis of electromagnetic exchange processes in DC power systems because of the random character of voltage and current.
Abstract: The paper is dedicated to the estimation of instantaneous reactive power in a DC traction power system. Currently, the integral and frequency methods are mostly used to define reactive power and do not give high accuracy in the calculations of power balance or cannot describe the essence of physical processes. The problem is complicated in DC electric transport systems due to random impulse character of voltages and currents. As a comparison, the calculation of reactive power according to various approaches was performed for the DE1 electric locomotive. It is suggested that the instantaneous reactive power should be used for the analysis of electromagnetic exchange processes in DC power systems. The paper shows the definition and main formulas for defining the instantaneous reactive power taking into consideration the random character of voltage and current. Numerical calculations together with statistical analysis were performed for two variants of experimentally recorded voltages and currents: the first one - on the bus-bar of traction substation, which supplies the section with the Pendolino trains in Poland and the second one - on the current collector of the VL8 electric locomotive in Ukraine. They confirm the validity of the aforementioned method.
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01 Jun 2019TL;DR: In this paper, a series of finite-element models simulating the stages of rock excavation and installation of temporary lining elements have been developed and analyzed, and the obtained results allowed to determine the cardinal change of force factors in temporary lining, depending on the stage of construction.
Abstract: The paper presents the results of a numerical analysis of force factors in temporary lining at the tunnel construction by New Austrian Tunneling Method (NATM). The relevance of the performed research is substantiated by the complexity of the temporary lining operation in the form of arches combination, anchors, and shotcrete that arose during construction of the Beskydskyi tunnel in Ukraine. NATM, used in construction, is associated with a change in the sectional area of the working and a staged installation of temporary lining, which leads to a gradual change in the stress-strain state of the “temporary lining – surrounding massif” system. In turn, this leads to a change in the force factors (bending moments and normal forces) in temporary lining. In this study, a series of finite-element models simulating the stages of rock excavation and installation of lining elements have been developed and analyzed. The obtained results allowed to determine the cardinal change of force factors in temporary lining, depending on the stage of construction. Changing the force factors at different stages of the tunnel construction by the NATM makes it possible to perform an optimal selection for temporary lining location.
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27 Feb 2019-Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport
TL;DR: Amelina and Cherednychenko as mentioned in this paper were the first to report their findings, with ORCID 0000-0002-8525-7096; M.L. Biliaiev and O. Berlov reporting ORCIDs 0000-0001-1457-9282.
Abstract: L. Amelina: ORCID 0000-0002-8525-7096; M. Biliaiev: ORCID 0000-0002-1531-7882; O. Berlov: ORCID 0000-0002-7442-0548; L. Cherednychenko: ORCID 0000-0002-1457-9282
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01 Jun 2019TL;DR: In this paper, the authors highlight the results of the complex analysis of the retaining pile structure with determining the stability coefficient by numerical methods and compare the stability coefficients of a slope by different methods for the existing landslide stretch for the public roadways of local significance C141017 (Lviv-Shehyni) - Sudova Vyshnia.
Abstract: The paper highlights the results of the complex analysis of the retaining pile structure with determining the stability coefficient by numerical methods. To achieve this purpose, after designing a structure with jet grouting piles, the research of the stability coefficients of the landslide hazard slopes in the software complex “OTKOS” and its stress state in the software complex LIRA-CAD system was conducted. The relevance of the completed research is to develop rational parameters of the pile structure. A comparison of determining the stability coefficient of a slope by different methods for the existing landslide stretch for the public roadways of local significance C141017 (Lviv-Shehyni) – Sudova Vyshnia was carried out. Originality of the paper lies in the fact that to determine the stability coefficient in the model, the layeredness of the slope under study is taken into account, and the nonlinear volumetric problem is solved in the course of the numerical analysis of the stress state. The rational distance between piles in the gap and the length of the pile under a certain percentage of cement and ground was justified.
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10 Jan 2019-Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport
TL;DR: A new technology to improve the management of train sections by dividing them into operational zones is developed, which will significantly reduce information flows and facilitate the work of the train dispatchers, create the necessary conditions for creative decision-making on the inter-sectional regulation, and contribute to increase in the service speed of trains.
Abstract: Purpose. The work is aimed to investigate the feasibility of transferring automatic control to low-density stations of the sections (according to the principle of supervisory control of trainline) to the operators at principal stations. Methodology. The article analyzes the work of heavy traffic sections of the Ukrainian Railways JSC. It was found out that the information workload of dispatchers who control the train movement at the sections of the main course, constantly exceeds the permissible level. The possibility of using the technology of supervisory control of train movement by the introduction of operational zones has been investigated. Findings. The authors found out that the capacity of receiving and departure tracks at the stations of the sections is extremely limited. The occupancy of run-around tracks by the out-of-work trains hinders any regulatory measures at the sections. Trains pass one after another without giving priority, that is, they pass through the section in the order in which they entered it. Due to the limited number of tracks at the pre-section intermediate station, freight trains are placed for run-around by the passenger ones at the distant approaches. This leads to a loss of service speed and reduces the level of utilization of the sections` working capacity. The introduction of operational zones will significantly reduce information flows and facilitate the work of the train dispatchers, create the necessary conditions for creative decision-making on the inter-sectional regulation, and will contribute to increase in the service speed of trains. Originality. The article developed a new technology to improve the management of train sections by dividing them into operational zones. In each zone, consisting of two or three run-arounds, the duty officer of the principal station, performing in this case the functions of the train dispatcher, can control the train movement. Practical value. It has been proposed to put trains from technical stations that idle due to uneven movement, especially the trains from the terminal stations (division points) of the locomotive circulation sections, to reserve routes of the pre-section intermediate stations. Laying the reserve tracks and their maintenance, taking into account the periodicity of use and reduced permissible speed, can be allowed according to less tight standards for the construction of the roadbed, ballast section, sleeper density, taking into account the use of switches and decommissioned tracks.