• Proceedings of the KSR Conference
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• 2011.10a
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• pp.412-419
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• 2011

With an increase in rail traffic, developing activities around structures of railway have been expanded. Inevitably, the changes to cross though sub-structures of railway have been getting increased. However, this situation affects on the safe operation of trains. Generated wheel load makes on the result in settlement on roadbed and damages on track materials. Therefore, via the numerical analysis were carried out for the box structure and subground using FEM analysis program called. Visual FEA/Geo 4.19. Parametric studies were performed by changing soil depth above box structure constructed in railway embankment. A standard live load was applied to simulate loads from train. Through this study, a minimum required soil depth above subground box structure was recommended based on deformation and stresses in concrete railway system.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2292-2299
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• 2011

The CBTC(Communication Based Train Control) system, a recent train control system, is a wireless communication based train control system that is operated in the moving block system control by tracking trains in real time. In additioin, the system helps to increase the volume of traffic by shortening driving headways through controlling moving block system control. Furthermore, driverless modes are performed by controlling ATP(Automatic Train Protection)/ATO(Automatic Train Operation). In this paper, controllable elements in ATO driverless train control system, affecting comfortable ride, will be analysed and applied to CBTC train control system that developed by POSCO ICT. Finally, the test results of improved comfortable ride will be showed by appling the developed system to the Gyeong-san light rail transit test track.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.965-968
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• 2004

Now a day, the Korean National Railroad is taking new age with the opening of KTX (Korea Train Express). Korean National Railroad is planning using the GSM-r for put KTX and existing equipment to a good. GSM-R is radio communication method selected by ERTMS (European Rail Traffic Management System). So a new algorithm for train movement is necessary to radio communication form. This paper is come up with an algorithm for like that situation.

• ETRI Journal
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• v.37 no.1
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• pp.11-20
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• 2015

This paper deals with optimal power allocation for channel estimation of orthogonal frequency-division multiplexing uplinks in time-varying channels. In the existing literature, the estimation of time-varying channel response in an uplink environment can be accomplished by estimating the corresponding channel parameters. Accordingly, the optimal power allocation studied in the literature has been in terms of minimizing the mean square error of the channel estimation. However, the final goal for channel estimation is to enable the application of coherent detection, which usually means high spectral efficiency. Therefore, it is more meaningful to optimize the power allocation in terms of capacity. In this paper, we investigate capacity with imperfect channel estimation. By exploiting the derived capacity expression, an optimal power allocation strategy is developed. With this developed power allocation strategy, improved performance can be observed, as demonstrated by the numerical results.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.11a
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• pp.9-10
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• 2019

서울시 첫 번째 경전철인 우이신설선은 2017년 9월 개통 이후 대중교통 불모지인 서울 동북부지역의 중요한 교통축을 담당하고 있다. 일평균 약 8만 명이 이용하는 우이신설선은 통행시간의 획기적인 개선과 지역 활성화에 기여하는 등 긍정적 효과가 있으나 개통 2주년이 지난 현재 출퇴근시 혼잡도 문제가 심화되는 등 대시민 서비스 측면에서의 쟁점도 제기되고 있다. 본 논문은 우이신설선 사례를 기반으로 서울시 경량전철 통행특성을 분석하고 첨두시 혼잡원인을 파악하여 계획단계부터 혼잡도를 고려한 시설설계 개선방안 등을 제시하였다. 통행특성 및 혼잡원인 분석은 우이신설선을 통과하는 개별 카드데이터를 활용하였으며, 더 나아가 카드데이터의 특성을 고려한 열차 내 혼잡도 산정 알고리즘을 연구·개발하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.163-168
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• 2007

A light railway operationis an effective means to solve a traffic problem of the city however, noise and vibration is pollution happened. This paper studied noise and vibration pollution of a light railway operation in order to let a decrease. The study range was only track condition and civil engineering structure condition. The way how we decrease noise and vibration in a protection vibration track, ballasted track, non-ballasted track, floating track trends was devoted is long rail laying, low vibration track lying. It was the most economic that the examination results track section a complement, and it was proved that a certain way.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.751-756
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• 2006

The purpose of this study is to grasp present condition of railroad noise, and forecast noise and presented basis data that ready noise reduction countermeasure. This study has predicted the level of noise reduction according to barrier by considering the characteristics of the cause of noise. These result drew using 'Prediction Model of NIER' and 'Shall03 of Germany'. This paper found important factors in railroad noise using this results and become forward syudy direction.

• International Journal of Automotive Technology
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• v.5 no.4
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• pp.239-245
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• 2004

It has been recognized that alternative fuels such as Liquid Petroleum Gas (LPG) show less polluting combustion characteristics than diesel fuel. Furthermore, engine performance is expected to be nearly equal to that of the diesel engine if direct-injection stratified-charge combustion of the LPG can be adopted in the spark-ignition engine. However, spray characteristics of LPG are quite different from those of diesel fuel. understanding the spray characteristics of LPG and evaporating processes are very important for developing efficient and low emission LPG engines optimized in fuel injection control and combustion processes. In this study, the LPG spray characteristics and evaporating processes were investigated using the Schlieren and Mie scattering optical system and single-hole injectors in a constant volume chamber. The results show that the mixture moves along the impingement wall that reproduced the piston bowl and reaches in ignition spark plug. LPG spray receives more influence of ambient pressure and temperature significantly than that of n-dodecane spray.

• Journal of the Korean Professional Engineers Association
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• v.43 no.6
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• pp.23-26
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• 2010

The first high speed railway in Korea was opened to traffic on April 1, 2004 and the second phase will be opened on November 1. 2010. Many technical problems that occurred during construction have been solved. In its early period of project, difficulties were encountered in design, construction of high speed line. because most of Korean railway engineers were familiar only with conventional railway. Now they understand the various phenomena occuring during operation of the KTX and have accumulated extensive technical knowhow. Valuable experiences and knowledges that have been obtained from frials and errors will lead to further improvement for the future project.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.203-205
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• 2008

전기철도의 에너지 소비형태를 다른 수송기관과 비교해 보면 에너지 소비 분담을 측면에서 약 8% 정도를 차지하고 있으나, 수송 분담율은 약 30%이상을 점유하고 있으며, 화물의 경우 수송량의 5%를 담당하고 있지만 에너지 소비는 약 1%미만으로 에너지 효율성이 높은 것으로 나타났다. 그러나 기존의 방법으로 에너지 소비에 대한 효율성을 비교 하는 것은 에너지 소비원이 다르기 때문에 문제가 있어 본 연구에서는 원유로부터 환산하는 효율 계산방법과 필요 에너지, 유효에너지 즉, 'exergie'에 의한 평가 방법을 제안하였다.