• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.569-575
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• 2022

This is a research thesis on the development of a monitoring and diagnosis device that prevents the risk of an accident through monitoring and diagnosis of a modular Main Circuit Breaker (MCB) using Vacuum Interrupter (VI) for Korean high-speed rolling stock. In this paper, a comprehensive MCB monitoring and diagnosis was performed by converging vacuum level diagnosis of interrupter, operating coil monitoring of MCB and environmental temperature/humidity monitoring of modular box. In addition, to develop an algorithm that is expected to have a similar data processing before the actual field test of the MCB monitoring and diagnosis device in 2023, the cluster analysis and factor analysis were performed using the WEKA data mining technique on the big data of Korean railroad transformer, which was previously researched by Tae Hee Evolution with KORAIL.

• Korean Journal of Occupational Health Nursing
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• v.33 no.2
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• pp.47-54
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• 2024

Purpose: This study aims to identify the level of subjective noise perception among School Meal Facility Workers and analyze the relationship between subjective noise perception and insomnia, as well as the factors affecting insomnia. Methods: School meal facility workers were surveyed from November 1 to December 31, 2021, and 717 people were selected as participants for the study. Using SPSS/WIN 25.0, t-test, x² test, and multiple logistic regression analysis were conducted. The Korean Insomnia Severity Index (ISI-K) was used to evaluate insomnia. Results: The variables that showed significant differences in insomnia in general characteristics, health-related characteristics, subjective health perception, and subjective noise perception of the study participants were mental disorders such as subjective health perception, work stress, depression, etc., gastrointestinal disorders, and subjective noise perception, among which subjective health perception, mental disorders such as depression, and subjective noise perception were analyzed as factors influencing insomnia. Conclusion: To improve the quality of insomnia and sleep among school meal facility workers, there is a need to improve healthcare, emotional management, and noisy work environments.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.4
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• pp.299-305
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• 2015

A statistical annoyance model to railway noise at platform was proposed by jury evaluation test performed in hearing laboratory. ITX-Saemaeul and Mugunghwa were chosen as the noise sources of the test, and announcement sound was included to simulate real situation. Logistic regression analysis produced %HA_LAB curve. Hosmer-Lemeshow test and classification accuracy test were used to verify the model's statistical significance. It was shown that the model which was generated from relatively small number of samples is statistically significant.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.645-653
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• 2012

This study analyzes the effects of the KTX driver's person-environment(job, organization, Coworker) fit on job satisfaction, organizational commitment and turnover intention. It, additionally, examines the mediating effect of job satisfaction and organizational commitment between person-environment fit and turnover intention. Consequence of the analysis indicates that person-environment fit has mostly meaningful influences on job satisfaction, organizational commitment and turnover intention. But person-job fit makes a meaningless impact on job satisfaction, and person-coworker fit also makes a meaningless impact on job satisfaction and turnover intention. The mediating effect of job satisfaction and organizational commitment is mostly effective, but the mediating effect of job satisfaction does not affect the relation between person-organization fit and turnover intention. In conclusion, this study implies that, in order to grasp KTX driver's turnover intention and to protect actual turnover, it is important to enhance job satisfaction and organizational commitment as well as to improve overall person-environment fit.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.604-608
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• 2012

Traditionally, the track circuits have been used for the purpose of train locating. However, the recent train control systems like a CBTC(Communications Based Train Control) do not utilize the track circuits to minimize the amount of ground signal devices. Therefore, there are increasing concerns over the system that can locate the position of train exactly without using the track circuits. Then, the contactless locating methods are added to ensure safety when the shunting sensitivity of the track circuit becomes low for the existing sections equipped with the track circuits. In this paper, a prototype of train locating device has been designed and tested, which utilizes the current phase difference upon magnetic field variation. The results show improved features of this method over the conventional track circuits method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8927-8932
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• 2015

A directional feeding method at the railway transformer is applied for supplying the power to the electric railway substations, and the pre-installed facilities with common feeder are utilized in preparation for the failure of feeding system and in finding a fault location in case that the catenary failure occurs. However, it is some difficulty in finding the fault location since there is an interface problem with the facilities when the supplying power system operates. In this paper, Auto Fault Locator Transfer Drive System (ALTDS) is designed to search for the fault location efficiently, and the measuring data are obtained and compared with the KORAIL standards. Further, the ground connection test is accomplished 24 times as the verification method, and it is shown that the methodology provides better performance than the existing traditional one.

• Journal of the Korean Geotechnical Society
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• v.31 no.9
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• pp.29-38
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• 2015

In this study, track dynamic interaction characteristics caused by the vehicle running through transitional section such as bridge abutments were studied using the finite element analysis program. The geometric condition of track was generated by trigonometric function and allowable maximum track irregularity is determined by KORAIL track maintenance criteria. The sub-infrastructure under rail fastener system was modelled by 3D solid elements. To reduce computational cost only half track line is numerically considered and the roller boundary condition was applied to each side of model. In this study, the vehicle-track dynamic interaction analysis was carried out for standard Korean transition section of concrete track and the dynamic behaviors were investigated. The dynamic characteristics considered are wheel load variation, vertical acceleration at body, and maximum Mises stress at each part of transitional section.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.256-263
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• 2009

KORAIL carries out an improvement project of railway signaling system for the conventional line from the existing method which permits a train to move within limited speed the ground signal of ATS(Automatic Train Stop) system. The proposed system makes possible that a train can be driven using a speed profile created by onboard signaling system(ATP) with the movement authority from ground balise. A driving test over 100,000km is being executed by developing a tilting train for the speed elevation on the conventional line. And, the introduction of the tilting train by ATP system to the Jung-ang line is expected. However, a speed elevation on a curved line section has a restriction. Therefore, research on safety braking model and train separation control technology for the localization of ATP system is required preferentially. In this paper, we presented a safety braking model of ATP system and a train separation control method that use ground balise as variable information provider, and executed a performance simulation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.121-128
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• 2016

The restructuring of Korean railway industry, separation of between train operators and an infrastructure manager, had been conducted in 2004 to increase the productivities of railway operations. However, the maintenance-staffs are still employed by Korail (train operator), not by the infrastructure manager, which led the maintenance of railway infrastructure to be conducted by the train operator. The infrastructure manager is now only taking care of financial transferring issues once the train operator requests expenses spent for facility maintenance. Such incomplete restructure may result in a lack of safety performance on railway operations as the roles and responsibilities are less likely to be assigned under the multiple train operators. Thus, this study proposes the way of structuring maintenance divisions and their roles and responsibilities to assure the safe work execution under the circumstance of multiple train operators on the same rail network.

• Journal of Korean Society of Transportation
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• v.30 no.4
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• pp.7-19
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• 2012

In this study of estimating the benefits of environmental materials, the CVM method used in environmental economics was applied to estimate the value of pedestrian environment improvement. After finding the Willingness To Pay (WTP) level of residents through CVM, this study attempts to calculate quantitative benefits from the pedestrian environment improvement. In this study, a survey targeting the inhabitants in Seongbuk-gu adjacent to a business area was carried out for pedestrian environment improvement considering form of payment, willingness to pay and such by establishing and showing several virtual scenarios depicting a quiet and comfortable pedestrian environment. As a result, the willingness to pay level of the Seongbuk-gu residents was 627 won of surcharge for pedestrian environment improvement per month. Additionally, the annual total benefits by pedestrian environment improvement was estimated within a range from 1,247,516,820 won to 286,305,110 won.