• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.338-343
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• 2010

This paper's purpose is to support the strategies of the Small and Medium Railroad industries requiring certifications and products inspections. This study's objects are Small and Medium Railroad enterprises pursuing the making products, development and serving services. Research's questions consist of 14 principal questions and some incidental questions which are made for finding out what Small and Medium Railroad enterprises need. This research's result will be used for KRRI Railroad Testing & Certification Center's study. This study will include market research, deciding strategies and setting a range of supporting level for Small and Medium Railroad enterprises who request a test and certification service. After due consideration based on surveys, this paper makes clear what enterprises need actually, also indicates the strategic ways to support by technology transfer and test assistance for Small and Medium Railroad enterprises.

• 한국정밀공학회지
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• 제30권10호
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• pp.1051-1059
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• 2013

In general, lateral ride comfort of railway vehicle is mainly influenced by a secondary suspension placed between the bogie and carbody. Higher operating speeds of train results in increased vibration of carbody, which has a negative impact related to the ride comfort. To solve this problem, researches to replace the conventional passive suspension with (semi)active technology in the secondary suspension of a railway vehicle have been carried out. The semi-active suspension using the magneto-rheological damper is relatively simpler system and has advantage in maintenance compared to the hydraulic type semi-active damper. This study was performed to reduce lateral vibration acceleration of carbody related to ride comfort of railway vehicles with a semi-active suspension system. The numerical analysis was conducted by replacing passive lateral damper with semi-active MR damper, and robust control with the MR damper was applied to the 1/5 scaled railway vehicle model.

• 한국대기환경학회지
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• 제27권2호
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• pp.214-224
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• 2011

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.205-207
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• 2008

Much signaling equipments are installed along railway tracks, and these are working in cooperation with each other, referring to other signaling equipment status. Existing railway signaling system uses signal cables to transmit this information. This system requires high cost for construction and have the problems like many faults from mistakes in cable connection, etc To solve these problems, JREast Inc. has developed a new signaling system based on network technology, utilizing Ethernet-Passive Optical Network(E-PON). In this paper, we review the system proposed by JREast Inc. and field test results performed on railway.

• Smart Structures and Systems
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• 제21권5호
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• pp.637-652
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• 2018

This paper presents a comparative study of displacement measurement using four sensors that are being used in the field: they are a ring gauge, a laser Doppler vibrometer (LDV), a vision-based displacement measurement system (VDMS), and an optoelectronic displacement meter (ODM). The comparative study was carried out on a brand-new high-speed railroad bridge designed to produce displacements within a couple of millimeters under the loading of a high-speed train. The tests were carried out on a single-span steel plate girder bridge two times with different train loadings: KTX and HEMU. The measured displacement is compared as raw and further discussion was made on the measurement noise, peak displacement, and frequency response of four sensors. The comparisonsare summarized to show the pros and cons of the used sensors in measuring displacement at a typical high-speed railroad bridge.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1124-1125
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• 2006

Railroad business had repeated continuous development. Is developing old line improvement skill that technique aging of railroad and hangup of transport capacity decline are happened and minimum expense is spent. Developed skill and equipment are important and examination and by this are important. Therefore, examine skill and examination formality of equipment, examination item, examination kind etc.. developed serving speed elevation of old line in treatise.

• Tribology and Lubricants
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• 제27권1호
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• pp.19-24
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• 2011

Metallic sintered brake pads are often applied to mid/high speed train due to their high strength and thermal characteristics. Imbalance contact between discs and pads can greatly influence the life span, one sided wear, discs attack/crack and threat the safety of the train during operation. In this research, we analyzed pressure/temperature distribution between brake pads and disks. Analyzed data had been verified and modified to conduct further tests of flexible brake pads with small/full-scale dynamo test. Flexible brake pads were installed to high speed train to conduct further tests to identify the differences between rigid brake pads and flexible brake pads. In result, Flexible brake pads showed outstanding disk thermal stability, one sided wear, noise and wear rate than rigid brake pad.

• International Journal of Railway
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• 제4권1호
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• pp.12-18
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• 2011

The ATS system is used to provide wayside signaling. Currently, the oscillation frequency is set at 78[kHz] in the normal state. As the on-board receiver crosses over the wayside transmitter, the oscillation frequency is changed by capacitors of the wayside transmitter in a manner dependent on the train speed. As the oscillation frequency is changed, the waveform is modified in the wayside transmitter as well as in the on-board receiver. When there are other signal systems such as a ATO system present near the wayside transmitter, frequency interference occurs. This phenomenon arises since other signals or communication frequencies present will be included in the waveform. Trains often stop due to these other frequencies included in the waveform. In this paper, a model of the interaction between the wayside transmitter and on-board receiver is suggested and frequency response in the wayside transmitter and on-board receiver in the presence of the other signals are estimated by the coupling coefficient. Also, the coupling coefficients are estimated, and the optimal value is proposed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.48-49
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• 2005

한국형 고속철도시스템은 최고운행속도 350km/h로 주행하는 고속열차(시제열차 7량 편성)의 개발에 성공하여 현재 시운전 시험을 통해 신뢰성과 안정성을 검증하고 있다. 국내 기술로 새롭게 개발된 한국형 고속철도 시스템은 고속운행에 따른 엄격한 안전요구사항을 만족해야 하며, 특히 고속-대량의 수송수단으로서 승객의 안전을 최우선으로 하기 때문에 다른 어떠한 시스템보다 엄격한 안전확인 및 성능검증을 위한 철저한 시험평가 과정이 필요하다. 본 연구에서는 한국형 고속철도 시스템 개발에 적용한 안전설계 요건의 분석내용을 제시하고, 고속철도 차량시스템의 안전성능 요건을 입증하기 위한 성능시험 체계로서 구성품 시험, 완성차시험(단차 및 편성 시험) 및 시운전 시험으로 구분한 한국형 고속철도 차량시스템에 대한 성능시험기준안을 소개하고자 한다.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.228-238
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• 2010

There is an increasing interest in research to help overcome the energy crisis that has been focused on energy storage applications in various parts of power systems. Energy storage systems are good at enhancing the reliability or improving the efficiency of a power system by creating a time gap between the generation and the consumption of power. As a contribution to the various applications of storage devices, this paper describes a novel algorithm that determines the power and storage capacity of selected energy storage devices in order to improve upon railroad system efficiency. The algorithm is also demonstrated by means of simulation studies for the Korean railroad lines now in service. A part of this novel algorithm includes the DC railroad powerflow algorithm that considers the mobility of railroad vehicles, which is necessary because the electric railroad system has a distinct distribution system where the location and power of vehicles are not fixed values. In order to derive a more accurate powerflow result, this algorithm has been designed to consider the rail voltage as well as the feeder voltage for calculating the vehicle voltage. By applying the resultant control scheme, the charging or discharging within a specific voltage boundary, energy savings and a substation voltage stabilization using storage devices are achieved at the same time.