• Title, Summary, Keyword: Recording

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Signal Processing for Perpendicular Recording Systems

  • Lee, Jun;Woo, Choong-Chae
    • Journal of IKEEE
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    • v.15 no.1
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    • pp.70-75
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    • 2011
  • Longitudinal recording has been the cornerstone of all two generations of magnetic recording systems, FDD and HDD. In recent, perpendicular recording has received much attention as promising technology for future high-density recording system Research into signal processing techniques is paramount for the issued storage system and is indispensable like longitudinal recording systems. This paper focuses on the performance evaluation of the various detectors under perpendicular recording system. Parameters for improving the their performance are examined for some detectors. Detectors considered in this work are the partial response maximum likelihood (PRML), noise-predictive maximum likelihood (NPML), fixed delay tree search with decision feedback (FDTS/DF), dual decision feedback equalizer (DDFE) and multilevel decision feedback equalizer (MDFE). Their performances are analyzed in terms of mean squared error (MSE) and noise power spectra, and similarity between recording channel and partial response (PR) channel.

Topology optimal design of magnetic recording system (자기기록장치의 위상최적설계)

  • Park, Soon-Ok;Choi, Jae-Seok;Yoo, Jeong-Hoon
    • Proceedings of the KSME Conference
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    • pp.618-621
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    • 2008
  • The magnetic recording system shows the difference of the magnetic recording density according to the direction of the magnetic field. The yoke shape of the recording system affects the magnetic field direction; therefore, the recording density may be raised by changing the shape. This paper intends not only to increase the magnetic flux density of the record region but also to reduce the recording loss of a specific region through the simultaneous design of the yoke and the magnet. The recording loss can be reduced by minimizing the magnetic flux of the adjacent area to the recording region. The topology optimization method is used to obtain the optimal shape both of the yoke and the magnet. And the commercial package, Maxwell is used to verify the result.

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Fine Granulation of Recording Layer in Perpendicular Magnetic Recording Media Using Oxide-interlayer (산화막중간층에 의한 수직자기기록층의 입자크기 미세화)

  • 김경환;공석현
    • Journal of the Korean institute of surface engineering
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    • v.37 no.4
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    • pp.196-199
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    • 2004
  • Seedlayers with low surface energy which increases the density of nucleation sites in the initial growth region of the recording layer deposited on them was studied to reduce grain size in recording layer. The seedlayer with low surface energy was so effective to attain finer grain in magnetic upper-layers. The Ni-Fe-O intermediate layer with low surface energy was found to be effective in reduction of grain size as well as magnetic cluster size of Co-Cr-Ta-Pt recording layer. Furthermore, the reduction of grain size in Co-Cr-Ta-Pt recording layer on Ni-Fe-O intermediate layer with low surface energy led to decrease the noise level in the high recording density region.

COMPLETION RATE OF THE MEDICAL RECORDING: PROBLEMS AND MEASURES FOR IMPROVEMENT (의무기록정리율의 문제점과 개선책)

  • Kim, Sae Chul;Kim, Min Soon
    • Quality Improvement in Health Care
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    • v.1 no.1
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    • pp.110-118
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    • 1994
  • As the first step to improve the medical recording for the hospitalized patients, we tried to identify problems of completion rate of the medical recording and made the completion rate of the medical recording within due date known to the public in the hospital and commended the best Department and resident officially. The results were as follows: 1. The average number of the medical recordings per a recorder by years of residency(average number to quorum) was 293.3(398.8) in 1st year, 82.5(68.1) in 2nd year, 21.2(8.3) in 3rd year, and 20.5(1.9) in 4th year-residents. There was only 2 residents who prepared the medical recordings more than the average of 125.6 recordings per a resident. 2. Among 13 Departments, the medical recording was wholly put in charge of the 1st year-resident in 6 Departments. The duty was shared with the 2nd year-resident in 5 Departments and the 3rd year-resident in 1 and the 4th year-resident in Only 1 Department. 3. The more the cases requiring the medical recording, the lower the completion rate(80% less than 100 recordings, 70% in 100-299, 60% in 300-399 and 33.3% in more than 400). 4. There was no difference in the completion rate of the medical recording before(1991) and after(1993) a public nitice(1992). However, 4 Departments showed improvement of 21-45% in the completion rate, and no case was found where billing for medical assurance was postponed due to delayed completion of the medical recording. 5. The completion rate was relatively low(72-78%) from January to March. The main reasons were shortage of men power due to preparation of board examination, attendance to military duty, and lack of training in the medical recording for the new 1st year-residents. 6. The official commendation of the best Department and resident by letters did not improve the completion rate of the medical recording. In conclusion, The main reason of the low completion rate of the medical recording was the fact that the 1st year-residents were almost exclusively responsible for the medical recording. Hence, it is mandotory that this practice gets staffs' attention to improve the completion rate. Public notice of the completion rate of the medical recording shows prompt improvement of the completion rate. Prize money rather than commendation by a letter for the best Department would also be more effective to improve the quality of medical recording.

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Dynamic characteristics of TbFeCo Magneto-Optical recording media at 680nm wavelength region (680nm 파장에서 TbFeCo 광자기 기록매체의 동특성)

  • Yoon, Doo-Won;Yeon, Cheong;Kim, Myong-Ryeong
    • Electrical & Electronic Materials
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    • v.8 no.5
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    • pp.558-563
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    • 1995
  • Dynamic characteristics of TbFeCo magneto-optical recording media at 680nm wavelength region were studied by means of computer simulation of disc structure and optimization of process variables during sputter deposition. With the slightly reduced Kerr rotation angle due to the reduced wavelength of optical laser source, the improved recording density in TbFeCo magneto optical media showing the CNR greater than 50dB could be achieved by only adjusting the thickness of dielectric and the recording layers when the wavelength of light source is changed from 780nm to 680nm. In addition, the recording power margin of 5mW and the 2mW minimum recording power was realized, It was shown from the present study that the increase in laser power density demonstrated feasibility of low cost and low power laser diode with the reduced optimum recording power.

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Eddy Current Effects on the High Density Magnetic Recording System (고밀도 자기기록 시스템에서 발생하는 와전류에 의한 자기 기록 필드 영향 분석)

  • Won, Hyuk;Park, Gwan-Soo
    • Journal of the Korean Magnetics Society
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    • v.16 no.2
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    • pp.149-156
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    • 2006
  • The frequency of the recording current and the rotating speed of the recording media are Increase for the high densities in perpendicular magnetic recording system with high conductive pole tip head and soft magnetic under-layer. In the paper, the frequency Induced eddy current and velocity induced eddy currents are analyzed by non-linear 3-dimensional finite element analysis. It it turned out that the frequency induced eddy current decreases the amplitude of the recording fields, whereas the velocity induced eddy current only distorts the distribution of the recording fields in the recording media.

A study on the method of the personnel recording of DHRMIS (국방인사정보체계의 인사기록방법에 관한 연구)

  • Cho, Young-Pyong;Yang, Hae-Sool
    • Journal of the Korea Industrial Information Systems Research
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    • v.13 no.2
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    • pp.88-99
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    • 2008
  • In this article, DHRMIS being developed with ERP at resent realizes the personnel affairs recording procedures that all the Ministry of National Defense, the army, the navy and the air force can use on personnel affairs in order to solve the problem of the personnel recording procedures of the MND and each of the troops such as using manual affairs together with computation affairs, absence of electronic recording managements in some of the institutions MND, insufficiency of real time recording, and excess of centralized managements to present and record the personnel data. The personnel recording procedures consist of standardized personnel recording procedures and definition of the personnel recording procedures. This personnel recording procedures propose 3 improvements such as an atomic electronic recording management, a real time recording affair, effective centralization and distribution of verification authority so as to guarantee authentication, integrity, reliance, and accessibility of personnel data. When proposed personnel recording procedures are realized through developing DHRMS, these can bring on unification of 10 recording management systems, reduction of recording management time from 45 days to 3 days, distribution of verification authority MND, each of the troops, each of the institutes, an individual, and reduction of some of the manual documents.

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Effect of Recording Density On the Reproducin Voltage in Perpendicular Magnetic Recording System (수직자기 기록장치에서 기록밀도가 재생전압에 미치는 영향)

  • 박관수;이향범;한송엽;이택동;징평우
    • Journal of the Korean Magnetics Society
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    • v.1 no.2
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    • pp.74-78
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    • 1991
  • The method for analyzing the recording and reading process of magnetic recording system by numerical simulation is introduced. which can simulate the effect of elements of the magnetic recording system. During the whole simulation, hysteresis characteristics must be included. Preisach model and finite element method are used to construct the algorithm. From the wave of recording current, recorded pattern of magnetization in recording media is simulated in recording process, and then waveform of reading signal in head coil is obtained in reading process. To show the validity of this method, this is applied to perpendicular magnetic recording system. Waveform of recording signal and reproduced signal is obtained in several density. Pattern of reprocuced voltage magnitude according to increase of recording density shows roll-off curve.

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