• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.337-342
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• 2003

The dynamic load effects are conveyed to the railway bridges through tracks which are generated by moving trains The dynamic load effects may vary due to the dynamic characteristics of the applied vehicle loads and the railway bridges containing the track system. However, the track effects have been neglected or simplified by spring elements in the most studies since it is quite complex to consider the track systems in the dynamic analysis models of railway bridges. In this study, track system on railway bridges is modeled using a three-dimensional discrete-support model that can simulate the load carrying behavior of tracks. In addition, this program is developed with the precise 20-car model and a continuous PSC(prestressed concrete) box girder bridge, which is the main bridge type of Korea Train express(KTX). Three-dimensional elements are used for both. The dynamic response of railway bridges is found to be affected depending on whether the track model is considered or not. The influencing rate depends on the traveling speed and different wheel-axle distance. The dynamic bridge response is decreased remarkably by the track systems around the resonant frequency. Therefore, the resonance effect can be reduced by modifying the track properties in the railway bridge.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.849-852
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• 2011

Dynamic response of high-speed railway bridges is important due to the possibility of resonance from continuous and repeated action of high-speed train running. Acceleration of bridge deck is important parameter in the evaluation of dynamic stability of bridges. This study investigated acceleration characteristics according to type of tracks.

• Journal of Positioning, Navigation, and Timing
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• 제1권1호
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• pp.15-21
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• 2012

For a GNSS receiver's robustness against RFI and the high accuracy of navigation solution in GNSS, interference source detection and mitigation are needed. In this paper, an adaptive lattice IIR notch filter is employed to track single-tone continuous wave and swept continuous wave interference signals, and an interference detection method is proposed. Furthermore, this paper presents interference source characterization algorithm using multiple ground stations' interference detection results. The measurement of the signal powers from each ground station is used to build weighting factors to estimate the type of the interference. The performance of interference detection algorithm is simulated for scenarios of GPS signal in the presence of single-tone continuous wave interference and swept continuous wave interference.

• 한국전자통신학회논문지
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• 제13권5호
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• pp.1135-1144
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• 2018

전동휠체어는 과거 장애인 및 노약자만 활용하는 장비로 인식되었지만, 최근 기능 및 형태의 변화를 통해 다양한 분야에서 다목적으로 활용되고 있다. 이에 본 논문에서는 다양한 분야와 환경에 적용될 수 있는 무한궤도형 전동휠체어의 프로토타입과 이를 제어할 수 있는 통합 모니터링 시스템을 제안한다. 이를 위해 기존 휠체어와 비교하여 운행 시 안전성 향상을 위한 프레임 응력 설계와 안드로이드기반의 앱(App)을 이용하여 전동휠체어를 자유롭고 손쉽게 조작할 수 있는 편의성을 제공한다. 아울러 다량의 전동휠체어를 원격에서 모니터링하고 제어할 수 있는 기능도 지원한다. 시스템 구현 및 성능평가 결과, 응력설계는 5번의 응력 해석을 통하여 존 미제스 응력 값이 정상범위에 해당하는 4.401%로 측정되었으며, 시스템의 제어를 위한 통신 부분에 대한 정확률도 98.75%로 측정되어 기존 휠체어와 비교하여 안전성 높은 것으로 입증되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3180-3186
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• 2011

A segmented scissors type switch has been developed for the urban transit maglev demonstration line to be commercialized near Incheon International Airport in 2013. Based on the design of the previous segmented 3-way switch, the scissors switch is composed of four segmented 2-way switches up/down and left/right and a turn table in the mid point. The main function of the scissors switch is to change the running direction of the train at end terminals. The developed scissors switch is planned to be installed in front of the 102 station, which has a side platform, of the demonstration line. The total length of the switch is 65m and the distance between the up and down track centerlines is 6m. The 2-way switches and turn table are made of steel box type beams, and have their own driving unit, locking unit, control unit, levitation and propulsion rails, and so on. Installed in the factory, a 100,000-cycle continuous operation test was carried out after manual and automatic test operations. The applicapability of the developed switch was verified through the measurements of the linearity of the track after repetitive operations, the mechanical operation noise, the load of the main driving motor, the safety of the control panel, the natural frequency of the girder, the deformation of the girder, and so on.

• Journal of Magnetics
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• 제6권4호
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• pp.109-118
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• 2001

A computer simulation, utilizing the Landau-Lifshitz-Gilbert equation, of ultra-high- density recording on continuous longitudinal media is carried out. The two important features of this work are the use of a planar-type head, which enables a high write field of 14183 Oe ts be generated at the center of the recording medium, and the media with very high coercivities up to 13010 Oe. From a systematic investigation, it is found that the optimum write field is higher than the medium coercivity by only 3400 Oe over a wide coercivity range. This new finding allows one to write an a medium with a very high coercivity by using a planar-type head. It is demonstrated that a reasonably good bit pattern with a bit density of 605 kfci is generated on the medium with a coercivity of l1720 Oe, and, combined with a high track pitch density of 100 ktpi, a recording density of 60 Gb/in$^2$can be obtained in a single layer medium. With an improved write- head designs even a higher recording density of 75 Gb/in$^2$may be possible since comparison of the results for the bit pattern from the present head profile and the ideal Lindholm profile indicates an increase in the track pitch density of about 27%. Even at this density, the thermal stability parameter (KV/kT) at room temperature is high enough (60) to provide ample room for thermal stability.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.400-405
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• 2005

The vertical slope of railway track is the differences of attitude for the horizontal distances between two positions of railway. It is better to be small vertical slope for the comfortable of passengers and the operation of railway system. However, the variable vertical slope is required that the simple vertical slope causes the huge quantities of embankment and cutting, the continuous welded rail tunnels, the continuous welded rail bridges, etc,. This research is for the relation between the vertical slopes and the trainset performances. This research shows that the effective vertical slopes for the operation of railway. The velocity of car and operation time and the consumed energy was considered for each vertical slope and type of car power system. The result of suitable vertical slope from this research is to be used for the design of railway plan.

• 대한토목학회논문집
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• 제14권4호
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• pp.907-913
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• 1994

철도교량은 도로교량과는 달리 궤도가 부설되어 있고 일반적으로 이 궤도는 레일을 연속적으로 용접하여 침목위에 고정시키므로 온도변화에 따라 종방향으로 큰 힘이 작용하게 된다. 따라서 철도교량의 설계는 수직방향의 열차하중 뿐만 아니라 종방향의 궤도축력을 고려하여야만 하고, 특히 장대교량의 경우 교량형식, 경간, 교각단면, 지점배치방법 등의 결정은 궤도축력에 의하여 지배된다. 본 연구는 교량상의 궤도축력에 대하여 이론적인 해석을 하고, 이 해석방법을 고속철도 교량설계에 이용할 수 있도록 하기 위하여 장대레일이 부설되어 있는 철도교량에서 궤도축력을 실측하여 이론해석결과치와 비교하였다. 최근 유럽철도에서는 궤도의 종방향해석모델을 유한요소로 하여 개발된 해석방법이 사용되고 있으나, 이 방법은 입력에 많은 시간이 소요되고 교량구조물의 세부설계가 완료되어야 하므로 계산결과 장대레일 허용응력이 만족되지 않을 때는 교량설계를 다시 해야 하는 동 교량의 설계 과정상 불편한 면이 많다. 따라서 일시에 수많은 교량의 형식에 대한 검토가 필요한 경부고속철도의 프로젝트의 경우 좀더 간단한 해석방법의 개발이 필요하게 되었다. 이 방법에 의한 해석결과는 유한요소법에 의한 해석결과치와도 큰 차이가 없으며, 또한 운행선상에서의 실측결과와도 잘 일치하므로 교량의 예비적인 설계에 매우 유용한 방법으로 활용될 수 있을 것이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집(한일합동학술편); 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.926-931
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• 1987

The present study is devoted to the development of a simplified teaching method whereby the control data of the 3-dimensional operations of a playback-type trial robot can be stored in a personal computer. The control data of the 3-dimensional operations are given using an instruction wand handled by an operator. The operator's task is only to track a desired robot path with the wand. The 3-dimensional position of the wand are measured by ultrasonic devices, the principle of which was developed for this study and is introduced in detail. In order to clarify the applicability of this method, experts were performed with respect to a continuous-path teaching and a pick-and-place task teaching which are typical jobs of robot operators.

• 문화기술의 융합
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• 제9권4호
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• pp.593-599
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• 2023

곡선부에는 차량-궤도의 하중불균형 등 다양한 요인에 의한 탈선의 위험이 내재 되어있어 도시철도에서는 탈선방지 가드레일을 설치, 운영하고 있다. 앵글형 탈선방지 가드레일은 가드앵글을 포함한 다양한 부품으로 구성되어 탈선을 방지하는 기능을 수행하는데 탈선이 발생하지 않더라도 구성품에서 다양한 손상이 발생하고 있어 지속적인 유지관리가 필요하다. 손상현황을 조사하여 손상 빈도가 높은 앵글형 탈선방지 가드레일의 구성품을 분류하였으며, 다양한 손상의 발생 조건 등을 조사하였다. 또한 손상원인을 공학적으로 분석하고자 정밀 3차원 수치모델을 이용한 수치해석을 수행하였다. 수치해석은 열차의 탈선하중을 해석적으로 모사하고자 정적상태의 극한하중조건으로 적용하였으며, 앵글형 탈선방지 가드레일, 레일, 차륜의 실제도면을 이용하여 모델링하였다. 손상현황조사와 수치해석 결과를 비교 분석하여 구성품의 손상에 대하여 공학적으로 규명하고자 하였다.