• 한국안전학회지
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• 제31권3호
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• pp.130-135
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• 2016

It is very hard to analyze the train derailment safety quantitatively at the curved section because of the diversified affect parameters including the complex interaction between wheel and rail, the train conditions such as the shape of wheel, suspension system, the track conditions such as the radius of curve, cant, transition curve, and the operation conditions, etc. Two major factors related to the running safety of railway vehicle are classified as the railway vehicle and the track condition. In this study, when the railway vehicle passing through curves of actual track condition of subway line NO.3 in seoul ($Yeonsinnae{\leftrightarrow}Gupabal$), the effect that has influence on running safety depending on rail inclination. The analysis result of 1/40 rail inclination condition is more favorable on running safety than other rail inclination conditions because derailment coefficient and wheel unloading ratio are the lowest.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.413-422
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• 2011

축전지는 차량을 기동할 때나 비상시의 제어전원으로서 철도차량의 구성품 중 매우 중요한 부분이다. 현재 널리 사용되고 있는 축전지로는 연축전지와 니켈카드뮴축전지 등이 있으며 점차 소형화 경량화 되어 가고 있는 추세이다. 또한 철도차량의 전자제어기술의 발달로 인하여 필요로 하는 전기용량이 늘어나고 있다. 따라서 다양한 종류의 고효율 축전지들이 신규 노선의 차량에 검토되고 있지만 철도차량용 축전지는 안전상으로 충분히 검증이 되어야 하며 또한 관리 측면에서도 어려움이 없어야 하는 요구조건으로 인하여 실제 적용하는 데에는 많은 어려움이 있다. 본 논문에서는 현재 철도차량에 적용된 축전지 사례를 조사하고 적용을 시도 중인 축전지들의 특성을 확인하여 안전 및 성능, 관리적인 측면에서 어떠한 문제가 있는지 검토하여 향후 축전지 발전 동향에 대하여 논하고자 한다.

• 산업경영시스템학회지
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• 제28권2호
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• pp.117-124
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• 2005

This study tries to develop the models of measuring the level of product availability accommodated for features of specific customers dividing customers into VIP customers and general customers. Functions of costs that the models are composed of are cost of holding safety stock and cost of lost opportunities. The existing model of measuring the level of product availability which focused on cost of holding safety stock for VIP customers should be reinforced by considering cost of lost opportunities caused by general customers' quitting trades with a company. This study tries to present realistic solutions for problems in making decisions related to the total inventory. This study concludes that the model of the level of product availability meeting general customers' needs is more efficient according to increasing of a latent demand of the general customers who quit trades with a company and the cost of lost opportunities.

• 한국IT서비스학회지
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• 제10권3호
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• pp.49-59
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• 2011

A ship scheduling model is presented for the raw material transportation problem with yard storage constraints in a steel mill. The problem is formulated as 0, 1 mixed integer programming considering such constraints as loading port conditions, ship size and hold capacity, unloading conditions, and yard storage space. In addition, inventory related constraints including safety stock are taken into consideration to support the continuous operations of steel making process. The proposed model has been implemented and applied successfully to a real world problem, and its results show the improvement of performance compared to the traditional method. For example, the arrival dates of ships are determined satisfying the constraints. The total inventory level is minimized at the stock yard as a result. Also, the safety inventory level is always kept at the planning stage, and the standard deviation of total inventory level is reduced significantly. Further research is expected to develop efficient heuristics to have a better response time for even larger scale problems.

• 한국안전학회지
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• 제31권3호
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• pp.28-33
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• 2016

Since defects in the wheels of railway vehicles, which occur due to wears with the rail, cause serious damage to the running device, the diagnostic monitoring system for condition-based maintenance is required to secure the driving safety. In this paper, we studied to apply a useful Cepstrum analysis to detect periodic structure in spectrum among the vibration signal processing techniques for the fault diagnosis of a rotating body such as wheel. In order to analyze in variations of train velocity, the Cepstrum analysis was performed after a domain change of the vibration signal from time domain to rotation angle domain. When domains change, it is important to use a interpolation for a uniform interval of the rotation angle. Finally, the Cepstrum analysis for wheel flat detection was verified by using the vibration signal including the disturbance resulting from the rail irregularities and the vibration of bogie components.

• 한국철도학회논문집
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• 제16권3호
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• pp.183-188
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• 2013

철도차량을 유지보수 하는 목적은 열차가 운행하는 동안 고장이 발생하지 않도록 하는 것이다. 최근의 철도차량은 전기전자 부품은 물론 IT기술이 접목되어 주기적인 예방정비 방식으로는 차량고장을 근본적으로 예방할 수 없게 되었다. 따라서 KTX에 RAMS가 적용되어 도입된 이후 코레일에서 도입하는 철도차량은 RAMS를 적용하고 있다. 새로 제작되는 차량은 운행초기 하자보증기간 동안 신뢰성 검증을 하게 되며, 유지보수 과정에서는 RCM 기법을 적용한다. 본 논문에서는 철도차량의 특성 및 운영 환경에 적합한 철도차량 신뢰성유지보수체계인 RCRM(Reliability Centered Rolling stocks Maintenance) 방안을 제시하고자 한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1916-1932
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• 2008

철도사고의 발생 확률은 적지만 한 번의 사고로 인하여 피해가 막대하고 빠르게 확산되는 특징이 있다. 이러한 예상치 못한 철도사고 예방을 위하여 열차안전운행의 최일선 접점에 있는 기관사의 역할은 무엇보다 큰 비중을 차지하고 있다 할 것이다. 철도안전법 시행 이전 기관사 양성은 각 철도운영기관에서 자체적으로 정한 자격기준, 교육기간, 실무수습을 거쳐 양성하였으며 동일차종을 운전하는 기관사 양성에 있어 철도운영기관 별로 각기 다른 기준으로 선발 교육함에 따라 철도차량운전자에 대한 양성 관리가 체계적으로 이루어 지지 않았다. 철도안전법 시행으로 철도차량 종류에 따라 면허의 종류를 분류하고 전문교육훈련기관을 지정하여 일정한 교육을 이수한 후 제3의 평가기관을 지정, 평가토록 함으로써 일정 수준이상 득점을 해야만 면허가 발급되는 체제를 갖추게 되었으며 교육훈련기관과 평가기관을 분리하여 운전자에 대한 능력을 객관적으로 검증할 수 있도록 하였다. 교육대상자에 따라 과목별 이론교육 시간을 달리 배정하고 실기교육의 대부분을 차지하고 있는 운전시뮬레이터의 취급시간을 최대한 확보하여 철도차량운전자의 자질을 극대화하는 교육프로그램이 되도록 설계하여야 한다. 본 논문을 통하여 면허취득을 위한 교육훈련의 효과를 극대화 하고 실용적인 교육을 위하여 필요한 제반 여건에 대하여 국내외 면허 교육훈련을 비교분석을 통하여 현행 제도의 문제점 및 개선방안에 대하여 연구하고자 한다.

• 한국항만학회지
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• 제14권1호
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• pp.37-45
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• 2000

Centralized safety stock in a periodic replenishment system which consists of one central warehouse and m regional warehouse can reduce backorders allocating the centralized safety stocks to regional warehouse in a certain instant of each replenishment cycle. If the central warehouse can not monitoring inventories in the regional warehouse, then we have to predetermine the instant of allocation according to demand distribution and this instant must be same for all different replenishment cycle. However, transition of inventory level in each cycle need not to be same, and therefore different instant of the allocation may results reduced shortage compare to the predetermined instant of allocation. In this research, we construct a dynamic model based on the assumption of monitoring inventories in the regional warehouse everyday, and develop an algorithm minimize shortage in each replenishment cycle using dynamic programming approach.

• 한국안전학회지
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• 제30권5호
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• pp.114-122
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• 2015

FMEA and FTA have been widely applied to the safety studies for railway systems respectively. But it would be more effective to use these two methods at a same time because these are complementary. This article suggests a FMEA-FTA combined analysis technique to evaluate the risk for railway systems. A FMEA-FTA combined risk evaluation model and process are proposed and a case study is dealt with for PBU(Pneumatic Breaking Unit), a major subsystem of a railway vehicle.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.857-865
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• 2010

Recently the demand of the driverless rolling stock is increasing with advancement of the stable communication technique and control technique. The automatic train operating system has advantages which takes low operating cost and is able to dispose elastically in demand. Beside it provides high safety and effectiveness because it will be able to control power, signal and communication system from Operation Control Center and the safety and effectiveness are high. The establishment of PSD, Platform Screen Door, is advanced in the goal which is passenger safety, fire protection, noise and dust reduction etc. When but, two advanced systems also have risks of operation delay and accident when two systems are not controlled smoothly. Thus, I'll introduce control method between onboard controller, door control unit in rolling stock and PSD controller to help system design.