• Title/Summary/Keyword: 트랙좌표계

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Dynamic analysis of railway vehicle by using track coordinates (트랙 좌표계를 이용한 철도차량 운동 해석)

  • Kang, Ju-Seok
    • Proceedings of the KSR Conference
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    • pp.818-823
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    • 2011
  • 6-generalized coordinates of absolute translational displacements and angular displacements measured at Cartesian coordinates system fixed at the ground has been used to describe general dynamic behavior of a rigid body in mechanical systems. However, track coordinates system moving with the centerline of the track can be used to develop dynamic formulations for railway vehicle. It is easy to impose the constraints of track coordinates by the virtue of track coordinates system moving with track centerline. In this analysis, dynamic equations of railway vehicle by using track coordinates system is derived and the simulation results are presented.

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A Study on the Dynamic Analysis of Railway Vehicle by Using Track Coordinate System (트랙좌표계를 이용한 철도차량의 동역학 해석에 관한 연구)

  • Kang, Juseok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.2
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    • pp.122-130
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    • 2013
  • Rail geometries such as cant, grade and curvature can be easily represented by means of a track coordinate system. In this analysis, in order to derive a dynamic and constraint equation of a wheelset, the track coordinate system is used as an intermediate stage. Dynamic and constraint equations of railway vehicle bodies except the wheelset are written in the Cartesian coordinate system as a conventional method. Therefore, whole dynamic equations of a railway vehicle are derived by combining wheelset dynamic equations and dynamic equations of railway vehicle bodies. Constraint equations and constraint Jacobians are newly derived for the track coordinate system. A process for numerical analysis is suggested for the derived dynamic and constraint equations of a railway vehicle. The proposed dynamic analysis of a railway vehicle is validated by comparison against results obtained from VI-RAIL analysis.

LaserPen: a new pointing device for a beam projector (프로젝터를 위한 지시 및 입력 장치인 레이저펜 시스템)

  • 최규완;이기혁
    • Proceedings of the Korean Information Science Society Conference
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    • pp.573-575
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    • 2003
  • 본 논문에서는 광학 시스템의 대칭성을 이용하여 프리젠테이션시 마우스와 같이 사용할 수 있는 레이저펜 시스템을 제안한다. 성능 평가를 위해 비슷한 상황에서 사용될 수 있는 자이로스코프 타입 포인팅 디바이스, 트랙볼 타입 포인팅 디바이스와 비교 실험한 결과 절대 좌표계를 이용하는 레이저펜 시스템이 가장 우수한 결과를 보였다.

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Map Creation Algorithm and Initial Attitude Estimation Method for Optical Head Tracker System (광학방식 헤드 트랙커를 위한 맵 생성 알고리즘과 초기자세 추정기법)

  • Lee, Young-Jun;Park, Chan-Gook
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.7
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    • pp.680-687
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    • 2008
  • This paper presents map creation algorithm and initial attitude estimation method for the proposed optical head tracker system. The optical head tracker system consists of the IR stereo cameras and infrared LEDs as features on the helmet. In order for the stereo camera to track the luminous LEDs, it must take in to account the light radiation from the LEDs to determine the position of the center points. The proposed map creation algorithm makes map data about the position of features center points on the helmet frame. Also, initial attitude estimation method is proposed to estimate the initial attitude and position of a pilot head from the camera frame by the use of the feature pattern on the helmet. Therefore, the head motion can be expressed with respect to the body frame of a flight.

Structure of Data Fusion and Nonlinear Statistical Track Data Fusion in Cooperative Engagement Capability (협동교전능력을 위한 자료융합 구조와 비선형 통계적 트랙 융합 기법)

  • Jung, Hyoyoung;Byun, Jaeuk;Lee, Saewoom;Kim, Gi-Sung;Kim, Kiseon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.1
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    • pp.17-27
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    • 2014
  • As the importance of Cooperative Engagement Capability and network-centric warfare has been dramatically increasing, it is necessary to develop distributed tracking systems. Under the development of distributed tracking systems, it requires tracking filters and data fusion theory for nonlinear systems. Therefore, in this paper, the problem of nonlinear track fusion, which is suitable for distributed networks, is formulated, four algorithms to solve the problem of nonlinear track fusion are introduced, and performance of introduced algorithms are analyzed. It is a main problem of nonlinear track fusion that cross-covarinaces among multiple platforms are unknown. Thus, in order to solve the problem, two techniques are introduced; a simplification technique and a approximation technique. The simplification technique that help to ignore cross-covariances includes two algorithms, i.e. the sample mean algorithm and the Millman formula algorithm, and the approximation technique to obtain approximated cross-covariances utilizes two approaches, by using analytical linearization and statistical linearization based on the sigma point approach. In simulations, BCS fusion is the most efficient scheme because it reduces RMSE by approximating cross-covariances with low complexity.

A Study on Iris Recognition by Iris Feature Extraction from Polar Coordinate Circular Iris Region (극 좌표계 원형 홍채영상에서의 특징 검출에 의한 홍채인식 연구)

  • Jeong, Dae-Sik;Park, Kang-Ryoung
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.44 no.3
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    • pp.48-60
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    • 2007
  • In previous researches for iris feature extraction, they transform a original iris image into rectangular one by stretching and interpolation, which causes the distortion of iris patterns. Consequently, it reduce iris recognition accuracy. So we are propose the method that extracts iris feature by using polar coordinates without distortion of iris patterns. Our proposed method has three strengths compared with previous researches. First, we extract iris feature directly from polar coordinate circular iris image. Though it requires a little more processing time, there is no degradation of accuracy for iris recognition and we compares the recognition performance of polar coordinate to rectangular type using by Hamming Distance, Cosine Distance and Euclidean Distance. Second, in general, the center position of pupil is different from that of iris due to camera angle, head position and gaze direction of user. So, we propose the method of iris feature detection based on polar coordinate circular iris region, which uses pupil and iris position and radius at the same time. Third, we overcome override point from iris patterns by using polar coordinates circular method. each overlapped point would be extracted from the same position of iris region. To overcome such problem, we modify Gabor filter's size and frequency on first track in order to consider low frequency iris patterns caused by overlapped points. Experimental results showed that EER is 0.29%, d' is 5,9 and EER is 0.16%, d' is 6,4 in case of using conventional rectangular image and proposed method, respectively.