• Journal of the Korean Society for Railway
• /
• v.7 no.4
• /
• pp.291-295
• /
• 2004

The Track geometry measuring on High-speed railway is the most important subject for the track construction and track maintenance work. Also the measuring accuracy is so significant part because it provides principle data for the maintenance plan and the assesment of working quality and can control the train speed limitation. From this point of view, it is very important to verify for the track recording coach(EM120) in KNR. According to the result of spectrum analysis, the noise near 1m waveband was found on the track recording data from EM120. So, New filter has been applied to remove the noise form track recording data. and it makes possible to acquire resembling result to real track geometry.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.5
• /
• pp.444-450
• /
• 2000

We prepared Co-Cr thin film for perpendicular magnetic recording media with facing targets sputtering system(FTS system) which can deposit a high quality thin film in plasma-free state and wide range of working pressure. The effect of sputtering conditions(argon gas pressure and substrate temperature) on the magnetic and the crystallographic characteristic of Co-Cr thin film was investigated. And the variation of perpendicular coercivity with the variation of film thickness was studied. As a result we obtained the high perpendicular coercivity of 1900Oe and the good dispersion angle of c-axis($\Delta$$\theta$$_{50}$) of 5$^{\circ}$on the film thickness of 100nm for the promising recording layer of perpendicular magnetic recording media.c recording media.a.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.899-901
• /
• 2004

This paper analyzes recording density according to the shape variation of Electric Probe writer, and present a shape design method for improving recording density in perpendicular electric recording device. The gradient of electric field has to be steep to improve recording density because transition region on the media becomes wider when recording. The optimum shape of electrode could be archived by using Response Surface Methodology and 2-Dimensional Finite Element Method.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.1938-1939
• /
• 2001

시스템을 입력과 출력간의 함수관계로 볼 때 출력에 대한 상대차수가 정의되지 않는 점을 특이점이라고 정의할 수 있다. 본 논문에서는 적절한 기하학적 조건을 만족하는 해석적인 시스템(analytic system)에 대하여 그러한 특이점의 성질을 살펴본다. 특이점을 지나는 궤적은 특이점의 특이도와 그에 관련된 함수 값의 부호에 의해서 특이점의 주변에서는 특이 매니폴드를 기준으로 한 영역에서 나머지 다른 영역으로 통과하거나 혹은 그를 기준으로 어느 한 쪽의 영역에만 머물러 있게 됨을 보임으로써 특이점과 이를 지나는 궤적의 상관관계를 명확히 규명하였다.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2008-2010
• /
• 2001

최근에 광 디스크 기기의 고배속화에 따라서 디스크의 재생 속도는 점차로 증가하고 있다. 이러한 경향에 따라 트랙킹 제어 루프에서 나타나는 디스크의 편심에 의한 외란의 영향은 더욱 커지게 되므로 기존의 선형 제어기만으로는 디스크의 편심량이 큰 경우에 고배속에서 원하는 트랙 추종 성능을 얻을 수가 없다. 본 논문에서는 이러한 문제점을 해결하기 위해서 반복 학습 제어 알고리즘과 드라이브 시스템의 액츄에이터의 주파수 응답 특성을 이용한 새로운 트랙 추종 제어 방법을 제안한다. 또한, 제안된 트랙 추종 제어 시스템의 제어 성능을 실험을 통하여 검증하여 본다.

• Macromolecular Research
• /
• v.9 no.6
• /
• pp.313-318
• /
• 2001

The present study relates to a method of manufacturing 100$\mu\textrm{m}$ thick cover layer for the high density digital versatile disc system (HD-DVD), which uses a high numerical aperture of 0.85 at 405 nm wavelength. Spin coating technique was investigated as means for manufacturing the cover layer within sufficient margins of thickness variation and with good mechanical properties including small radial and tangential tilts. The influence of processing variables such as spinning speed, spinning time, and dispensing position was investigated. The effect of viscosity of UV-curable resin was also investigated.

• International Journal of Internet, Broadcasting and Communication
• /
• v.12 no.4
• /
• pp.128-136
• /
• 2020

In this paper, we presented a simple hologram recording set for learners to broaden their program choices and experience holographic techniques with lifelong education programs. In order to obtain quality 3D images, the quality of light sources and recording mediums, which are the main elements of hologram recording, must be good. In addition, due to the characteristics of the hologram, the ambient vibrations shall be minimized for accurate interference pattern recording. The simple hologram recording set presented in this paper has not significantly restricted in space and location, and anyone can easily experience it at a reasonable price compared to the existing hologram production method. Also, it can make two different type of hologram (transmission and reflection) for providing easy access to recording and reconstruction of the hologram. Experiments have shown that holographic manufacturing practices are a very useful way to educate the public on optics and photonics technologies.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.10 s.241
• /
• pp.1119-1129
• /
• 2005

A new measurement system of wall pressure fluctuations on a rotating machinery, composed of digital recording device, was developed and evaluated. The small-sized digital recording device was attached on the rotating machinery and then was detached for data reduction. In order to obtain the system transfer function of the digital recording system, a dynamic calibration was performed utilizing the signal from a 1/8 inch B&K microphone as input. The time history of the unsteady pressure was then reconstructed from the output of the sensor by using this transfer function. The reconstructed pressure signals showed good agreement with the reference signal in both temporal and spectral sense. This sensor was then used to measure the wall pressure fluctuations on a rotating blade. An array of microphones were installed on the blade in the circumferential and radial directions. Various statistical moments were obtained from the measurement data set. Comparison of these quantities with the existing studies demonstrated satisfactory agreement. These tests give credence to the relevance and reliability of this device for applications in more complicated turbulent rotating machineries.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.11
• /
• pp.2439-2450
• /
• 1997

As recording densities increase in digital magnetic recording channels, the performances of digital detection techniques such as PRML and DFE degrade significantly due to nonlinear distortion in recording channels. The primary impediments for hgih-density recording are generally classified as nonlinear transition shift, which can be reduced substantially by the precompensation technique, and partial erasure which usually requires sophisticated nonlinear equalization techniques. In order to acheieve the highest density recording, accurate estimation of the parameters associated with these two noninear distortions is crucial. In this paper, a new estimation technique to distinguish these two different nonlinear effect using a proposed adaptive algorithm in time domain is presented. The effectiveness of the proposed adaptive approach to identify uniquely the nonlinear parameter with bias is demonstrated by computer simulation.

• The Journal of Korean Academy of Prosthodontics
• /
• v.25 no.1
• /
• pp.253-267
• /
• 1987

The purpose of this study was to improve limitations and disadvantages of the mechanical pantograph and the Visi-Trainer, and to design the reliable and reproducible device mandibular movement tracking device (MMTD) that is more simple, convenient and save the chair time than the mechanical pantograph and Visi-Trainer. MMTD was consist of head frame, horizontal bar, condylar path tracking stylus holders, anterior path tracking stylus holder, two condylar path plastic recording plates, one anterior path plastic recording plate, toggles and open occlusal clutch. To prove the reliability and reproducibility of MMTD, a five adults were selected and mandibular condylar movement was recorded one time by the mechanical pantographic tracing and MMTD. The border movement recording of the mandibular incisor (frontal, sagittal and horizontal) was also recorded by Visi-Trainer and the MMTD. The obtained results were as follows; 1. The condylar movement path (sagittal, horizontal) of the MMTD was not coincidence with that of mechanical pantograph. 2. Measurements of the angulation which established between working and balancing path records by use of the mechanical pantograph and MMTD, there was no significance. 3. In a view of MMTD's reproducibility, there was revealed almost similar recording pattern. 4. The border movement recording of the mandibular incisor by the MMTD and the Visi-Trainer showed almost same reliability and reproducibility. 5. The subjects were able to his original mandibular movements by use of open occlusal clutch in the MMTD.