• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1453-1458
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• 2006

KTX Railway rolling stock wheel run its course to corrode, deteriorate and wear away through out the time. So it is natural that the performance and ability of wheel gets declined. The frequency characteristic analysis were accomplished to above trend and shock wave flow to wheels were examined. The result will be used to find Railway rolling stock wheel crack and maintenance method hereafter.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.349-356
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• 2002

This paper describes a mathematical programming model for constructing the rolling stock assignment plan. This plan is a schedule which assigns daily routings, maintenance activities, and other tasks to trainsets. A generalized set partitioning model which is a kind of integer programming model is suggested as a model for constructing the assignment plan. And a column generation method are suggested as a solution method.

• 품질경영학회지
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• 제30권3호
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• pp.53-65
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• 2002

This paper studies an economic manufacturing quantity (EMQ) model with two types of failures and planned preventive maintenance of the production facility. One is a type I (major) failure which should be corrected by a failure maintenance and the other is a type H (minor) failure which can be minimally repaired without interrupting the production run. The objective is to determine the lot size and preventive replacement policy minimizing the long-run expected cost per unit time. We consider a control policy with a constant production lot size and preventive maintenance after completing n production runs. It is assumed that both preventive and failure maintenance times are random and the demand arriving during a stock-out period is lost. An expression for the expected cost per unit time is obtained in the general case. A special case is discussed and numerical results are provided.

• KIEAE Journal
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• 제10권4호
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• pp.29-37
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• 2010

The industrialized countries have promoted the rehabilitation of existing housing units as a national agenda, such as green policies, whereas korea, although having a housing stock as huge as that of world countries, have focused on the growth of housing by constructing new units rather than rehabilitating existing ones. Today, it has been so long since many multiple dwellings in Seoul and in the vicinity of Seoul were constructed. There were, however, very few political efforts to encourage the rehabilitation of housing. Today, substantial time has passed since multiple dwellings in Seoul and the first-stage new cities such as Bundang and Ilsan were constructed. What is required to maintain the quality of the existing housing and use it with safety is to promote the engineer of maintenance for multiple dwellings to work the maintenance of existing multiple dwellings. The objective of this study is to compare and analyze the maintenance qualification system of multiple dwellings of Japan, and then to propose to raise engineers of maintenance for multiple dwellings in korea.

• Structural Monitoring and Maintenance
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• 제6권3호
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• pp.219-235
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• 2019

Scheduled inspections of common crossings are one of the main cost drivers of railway maintenance. Prognostics and health management (PHM) approach and modern monitoring means offer many possibilities in the optimization of inspections and maintenance. The present paper deals with data driven prognosis of the common crossing remaining useful life (RUL) that is based on an inertial monitoring system. The problem of scheduled inspections system for common crossings is outlined and analysed. The proposed analysis of inertial signals with the maximal overlap discrete wavelet packet transform (MODWPT) and Shannon entropy (SE) estimates enable to extract the spectral features. The relevant features for the acceleration components are selected with application of Lasso (Least absolute shrinkage and selection operator) regularization. The features are fused with time domain information about the longitudinal position of wheels impact and train velocities by multivariate regression. The fused structural health (SH) indicator has a significant correlation to the lifetime of crossing. The RUL prognosis is performed on the linear degradation stochastic model with recursive Bayesian update. Prognosis testing metrics show the promising results for common crossing inspection scheduling improvement.

• 한국안전학회지
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• 제36권2호
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• pp.1-9
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• 2021

The 8200-unit electric locomotive, which is a high-efficiency multipurpose electric locomotive, is a German model, namely BR152 series ES64F, and it is manufactured to suit the operating conditions in Korea. Since 2003, 83 locomotives have been introduced in Korea, and they have been operating in the general railway sector for both passenger and freight transport. Although more than 15 years have passed since their first introduction, owing to the characteristics of vehicles introduced overseas, responding promptly to failures has been difficult owing to problems related to factors such as transfer of technology and procurement of parts for maintenance. Furthermore, there have been difficulties in operating the locomotives on the basis of the manufacturer-recommended time-between-overhaul (TBO) cycle. Therefore, a new TBO should be determined. To support the development of a reliability-based maintenance system, this study conducted a reliability and TBO analysis by using failure data obtained from KOVIS, and future management measures are presented.

• 한국의류학회지
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• 제28권8호
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• pp.1165-1174
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• 2004

The purpose of this study was to survey on the actual condition disposable coveralls of railroad rolling stock maintenance workers. The data were obtained from 100 male workers of railroad rolling stock maintenance wearing disposable coveralls using a questionnaire. The results were as follows. Disposable coveralls were exchanged into new ones in a week or 1-2 weeks. The major reasons of the exchanges were ＇Because it was contaminated(76.2%)＇ and then ＇It was torn(23.0%)＇ The response to the wearing frequency was the highest in ＇As possible as freqeuntly＇, and then ＇Sometimes＇ When workers were reluctant to wear the coveralls, the first reason was heat owing to wearing the coveralls. Therefore, wearing frequency became lowered in Summer. The torn parts of disposable coveralls most frequently were around the armhole and the crotch. The contaminated parts followed with the cuffs, the arm, and then the back. The uncomfortable parts were around the neck and the armholes. Workers felt uncomfortable because of heat and sweat caused by garment design obstructed convective airflow. Second, they complained that the coveralls make them irritated in a toilet. Third, they dissatisfied with materials of coveralls because the soils like oil were soaked into the coveralls and stained on the inner clothing. In regard of the color of coveralls, worker＇s favorite color was blue. In regard of style, the preferences to the separate style with a hood and the coveralls style with a hood were 49.0% and 25.0%, respectively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1335-1344
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• 2010

도시철도는 시민을 빠르고 안전하게 수송하는 대중교통의 중심축이다. 도시철도차량의 유지보수는 고장 방지를 위한 예방정비의 개념이며 정해진 규정과 정비지침에 따라 시행되어야 한다. 신뢰성 있는 검수설비는 유지보수의 정확성과 전동차 운행의 정시성을 보장할 수 있다. 부산도시철도 전동차 검수용 검수설비를 자체 기술로 개발하여 활용한 사례 연구를 통해 유지보수 과학화와 전동차 안전운행 및 업무 효율 향상 방법을 고찰하고자 한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1607-1612
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• 2007

To assure safe usage of railway rolling stock, it is important to evaluate the strength of the wheel which is core part in bogies. However, conventional standard testing methods using destructive technique could not evaluate mechanical properties of degraded wheels during rolling stock maintenance work. Instrumented indentation test is a new way to evaluate nondestructively the strength of mechanical components by analyzing indentation load-depth curves. In this study, to evaluate tensile strength of the wheel, instrumented indentation test is performed nondestructively according to KS B 0950. Furthermore, test results are examined by tensile test in accordance with KS R 9221.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.234-240
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• 2010

Display Unit(DU) of TCMS is very useful device display many data for operation and maintenance graphically. At This Time, rolling stock is reducing the wiring and size of desk for cutting down on their cost and making light weight. Dual Du(Display Unit) of TCMS could make the desk of cab simply by integrating cab's switches and gauges. Dual DU is not only can reduce the wiring and simplify desk of cab but also can making system of TCMS reliable by including backup function each other. For this reason. In this paper, advantages, application and example analysis of Dual DU of TCMS for rolling stock are described through the ongoing projects.