• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.427-430
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• 2005

The study for seismic characteristics of square concrete-filled steel tubular (CFT) columns is analytically conducted. For predicting the strength and ductility of CFT columns, fiber analysis technique is used. The analytical results show reasonable agreement with experiment results. The influence of the steel tube on the lateral response of CFT columns is studied for the evaluation of seismic performance.

• Tribology and Lubricants
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• v.29 no.1
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• pp.19-26
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• 2013

Cu-matrix sintered brake pads and low-alloy heat-resistant steel are commonly applied to basic brake systems in high-energy moving machines. In this research, we analyzed the tribological characteristics to determine the influence of the air velocity between the disk and pad. At a low brake pressure with airflow, the friction stability was decreased as a result of the lack of tribofilm formation at the disk surface. However, there were no significant changes in the friction coefficient under any of the test conditions. The wear rates of the friction materials were decreased with an increase in the airflow velocity. As a result, the airflow velocity influenced the friction stability, as well as the wear rate of the friction materials and disk, but not the friction coefficient.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.228-232
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• 2014

The magnetic field generated by the feeding line of a wireless power transfer system induces voltage on the rail of a railway system. The induced voltage of the rail can have a bad influence on the track circuit and on safety. This paper simulated three feeding lines to study the relation between the feeding lines and the induced voltage of the rail; it also proposed magnetic field distribution of the feeding line to reduce the induced voltage.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.105-115
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• 2017

The purpose of this study is to find the railroad work characteristics that influence stress of workers in the field of Railroad electricity including railroad signaling. After a self-administered questionnaire survey was conducted from Feb. 13 to Mar. 10 of the year 2017, 445 questionnaire copies were analyzed. Objective work characteristics include total working period, current workplace, work type, train service count, train line type, a type of train in charge, failure/accident participation count, work on holidays, and work hours. Subjective work characteristics include work life satisfaction and subjective work intensity. According to bivariate analysis, stress was different depending on all railroad work characteristics. According to multivariate analysis, total working period, train service count, a type of train in charge, work on holidays, work life satisfaction, and subjective work intensity were found to be influential factors. The moderating effect of subjective work characteristics was not found in the relation between objective work characteristics and stress. Therefore, it is necessary for companies to pay attention to the influential factors on stress and manage stress.

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.75-84
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• 2017

The purpose of this study is to find the relation between the detailed categories of the self-efficacy of workers in the field of railroad signaling and the detailed categories of their fatigue in the use of analysis of moment structure(AMOS) model. A self-administered questionnaire survey of workers in the field of railroad signaling had been conducted and a total of 341 copies were analyzed. This study had the assumption that their general self-efficacy and social self-efficacy would negatively influence their physical fatigue and mental fatigue. As a result, their general self-efficacy negatively influenced their physical fatigue and mental fatigue, whereas their social self-efficacy didn't influence their physical fatigue and mental fatigue. Therefore, it is possible to reduce the fatigue of the study subjects by enhancing corporate support to increase their general self-efficacy.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.320-328
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• 2017

In order to analyze the influence on derailment safety according to the aging of primary rubber springs widely applied to railway vehicles, characteristic tests were carried out on aged primary rubber spring samples. To analyze the effect of primary rubber spring aging on derailment safety, a vehicle dynamic analysis was carried out. The results of the vertical characteristics test for the rubber spring specimens with 17 years of service life revealed that the displacement restoration function was degraded due to rubber aging and the spring stiffness significantly increased. The results of the running dynamic analysis simulating the twist track running in accordance with the EN14363 standard, compared with the normal vehicle model (Case 1), showed that the derailment coefficient and the wheel unloading of the vehicle model (Case 2) using the aging primary spring characteristic increased, and the derailment safety was degraded. IN particular, it was found that the derailment safety due to the reduction of the wheel load is weak in the transient section where a steep slope change occurs.

• International Journal of Railway
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• v.5 no.4
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• pp.156-162
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• 2012

When a vehicle passes through turnout, it is required to minimize the changes of lateral force for running safety of vehicle. Therefore, it is necessary to analyze interaction between the vehicle and the turnout in order to estimate the lateral force and the derailment coefficient on the turnout. In this paper, analysis model of the vehicle and turnout are established and analysis is carried out when the vehicle passes through turnout in order to improve running safety of the vehicle on turnout. To verify the vehicle and turnout analysis model, the contact points between wheel and rail and the influence of changing cradle and tongue rail are also discussed.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.289-296
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• 2014

This study analyzes, based on survey of the behavior of 288 railroad tour conductors. how deep acting and surface acting, which were both classified as emotional labor, influence customer orientation. It also analyzes the moderating effect of POS (perceived organizational support) on emotional labor and customer orientation. The following are the summarized results of the analysis. First, railroad tour conductors' deep acting has a positive influence on customer orientation. And surface acting has a negative effect on it. Second, after the moderating effect of POS has been studied, it is found that POS does not appear to have a moderating effect on customer orientation of deep acting but does appear to have a moderating effect on customer orientation of surface acting. In conclusion, this study implies that it is important, to railroad tour conductors, that organizational level support enhance customer orientation; it is also important to manage railroad tour conductors' emotions in order to enhance customer orientation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.4
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• pp.577-583
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• 2013

We have analyzed influence of potential rise in negative bus, which caused by decrease of power feeding line insulation, upon protecting method of DC ground protection device which detecting potential rise between negative bus and ground in order to detect ground fault in the rubber wheel system. For this purpose, we proposed negative potential equation between negative bus and ground and calculated negative potential according to system condition changes by estimating power feeding line insulation changes in steel wheel system and rubber wheel system, and equalizing DC power feeding system when ground fault occurred. Also, in order to estimate negative potential of real system, we modeled the rubber wheel system, and simulated normal status, grounding fault occurrence and power feeding line insulation changes. In normal status, negative potential did not rise significantly regardless of vehicle operation. When ground fault occurred, negative potential rose up over 300V regardless of fault resistance. However, we also observed that negative potential rose when power feeding line insulation dropped down under $1M{\Omega}$. In conclusion, our result shows that in case of rubber wheel system unlike steel wheel system, relay will be prevented maloperation and insulation status observation can be ensured when ground over voltage relay will be set 200V ~ 300V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.251-251
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• 2010

Linear induction motor performance for a light-weight urban transit has been established and verified. In this paper, linear induction motor is analyzed by finite-element method to consider influence of construction of secondary reaction plate on the transverse edge effect. With this effective analysis method, various models with overhang and cap have been analyzed to consider the relationship between the construction of secondary reaction plate and the transverse edge effect.