• 한국자기학회지
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• 제7권2호
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• pp.97-102
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• 1997

자기헤드의 오프트랙 성능은 하드디스크 드라이브에서 트랙 피치를 결정하는데 사용되고 오프트랙 성능이 트랙 피치에 관한 함수가 747 곡선이다. 본 논문에서는 747 곡선을 컴퓨터를 이용하여 시뮬레이션 하였다. 헤드의 측면재생과 기록변수는 3차원 유한요소법을 이용한 자장해석을 이용하여 구하였고, 신호대 잡음비 (signal to noise ratio : SNR) 계산을 위한 헤드의 재생 신호와 잡음은 가역정리를 이용하여 구하였다. 생성된 747 곡선에 의하면, 소거밴드의 폭이 클수록 또한 유효 신호대 잡음비 SNR$_{eff}$이 작을 수록 오프트랙의 성능이 향상되었다. 기록된 트랙폭이 4.1 .mu. m 인 평면 실리콘 헤드를 사용하여 시뮬레이션으로 생성된 747 곡선과 스핀 스탠드 (spin stand)로 측정된 747 곡선을 비교했을 때, 두 곡선이 비슷하였으며 이로부터 본 시뮬레이션의 타당성을 입증할 수 있었다.다.

• 정보저장시스템학회논문집
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• 제8권2호
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• pp.61-66
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• 2012

In HDD industry, many technologies have been developed and investigated as means to increase the areal density of drives. Especially, heat assisted magnetic recording (HAMR) system has been considered as the next generation storage device. Most of the HAMR systems use near field optics as heating mechanism. Therefore, light delivery system is indispensable. We considered the light delivery system with laser diode (LD) mount and optical fiber. Mass and stiffness of the HAMR system using these LD mount and optical fiber are changed. The mass and stiffness of the HAMR system affects the slider dynamic behavior. It is necessary to analyze touch down (TD) and take off (TO). And, we performed the TD-TO experiment with HAMR suspension. Finally, we analyzed the result of TD-TO experiments. And we suggested the design of HAMR suspension to improve TD-TO performance.

• 인터넷정보학회논문지
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• 제4권2호
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• pp.31-37
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• 2003

최근 움직임 포착 시스템은 애니메이션 연구 분야에 가장 활발하게 적용되고 있다. 움직임 데이터의 포착은 움직임 포착 시스템은 실제 배우의 움직임과 연결하여 이루어진다. 본 연구는 기하학적 평균 필터를 이용하여 움직임 데이터를 편집하는 방법에 대해 다룬다. 포착한 움직임 데이터에 잡음이 끼면 부자연스러운 동작을 생성하기 때문에 동작을 자연스럽게 만들어 내는 중간 과정이 필요한데 기하학적 평균 필터를 이용하여 자연스러운 동작을 생성할 수 있도록 한 것이다. 실험 결과는 기하학적 평균필터가 다양한 공간필터 중에서 움직임 데이터의 잡음을 제거하는데 가장 우수함을 보여준다. 본 연구의 제안 방법은 실시간 애니메이션, 가상현신, 3D 응용분야등에 다양하게 응용 가능하다.

• Annals of Clinical Neurophysiology
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• 제2권2호
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• pp.107-113
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• 2000

Background & Objectives : Motor evoked potentials(MEPs) to magnetic trans cranial stimulation were performed to evaluate upper motor neuron involvement and relationship to lower motor neuron involvement in motor neuron disease patients. Method : MEPs were obtained in the 17 consecutive patients with motor neuron disease. These patients were divided into three group based on clinical evidence of upper and lower motor neuron involvement, bulbar symptom; amyotrophic lateral sclerosis(ALS), progressive muscular atrophy(PMA), progressive bulbar palsy(PBP). MEPs were recorded from abductor pollicis brevis and abductor hallucis muscles. Abnormal MEPs were defined by delayed central motor conduction time or absent MEP. Results : MEPs were abnormal in 64%(11/17) of patients; 100%(7/7) in ALS, 64%(4/7) in PMA, 0%(0/3) in PBP respectively. In 68 total recording muscles, 34 muscles had evidence of motor weakness and showed abnormal responses in 59%(20/34). Whereas 34 muscles with normal strength, only 3%(1/34) of muscles showed abnormal response. Conclusion : MEPs are well correlated with upper motor neuron signs in ALS and may detect masking upper motor neuron signs in PMA. The muscles with lower motor neuron sign(weakness) usually relate with abnormal MEPs reponses.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.479-483
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• 2006

As high-definition television(HDTV) broadcasting were generalized, there have been many researches and developments about large storage capacity and fast data transfer rate in optical disk drives(ODD). Pickup actuators must have high flexible mode frequencies and gain margins. Flexible modes are caused by the flexibility of moving parts in the actuator and a servo bandwidth is limited by them. As a result, the system becomes unstable for high-speed operations in high density reading and recording. In this paper, we suggest improved modeling method that considers the bonding layer. And, flexible mode frequency of actuator is improved by Design of Experiment of lens holder. Magnet circuit is designed considering the relation with moving part. Through improving yoke design, the magnetic flux is changed and DC tilt is reduced. Consequently, we designed actuator which has high flexible mode frequency and gain margins.

• The Journal of the Acoustical Society of Korea
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• 제21권2E호
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• pp.71-80
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• 2002

This paper suggests the Cardioid beamforming algorithm of the doublet sensors employing DIFAR (directional frequency analysis and recording) sensor signals in the frequency domain. The algorithm enables target bearing estimation using the signals from directional sensors. The algorithm verifies its applicability by successfully estimating bearings of a target projecting ten narrow-band signals in shallow water. The estimated bearings agree very well with those from GPS (global positioning system) data. Assuming the bearings from GPS data to be real values, the estimation errors are analyzed statistically. The histogram of estimation errors in each frequency have Gaussian shape, the mean and standard deviation dropping in the ranges -1.1°∼ 6.7°and 13.3∼43.6°, respectively. Estimation errors are caused by SNR (signal to noise ratio) degradation due to propagation loss between the source and receiver, daily fluctuating geo-magnetic fields, and non-stationary background noises. If multiple DIFAR systems are employed, in addition to bearing, range information could be estimated and finally localization or tracking of a target is possible.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2010년도 임시총회 및 하계학술연구발표회
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• pp.70-71
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• 2010

In this study, We fabricated FePt-based perpendicular patterned media using a selective combination of E-beam lithography and either Ar plasma etching (deposition-first process) or FePt lift-off (deposition-last process). We employed the deposition-last process to avoid chemical and structural disordering by impinging Ar ions (deposition-first process). For a patterned medium with 100 nm patterns made by this process, the out-of-plane coercivity was measured to be 5 fold larger than its in-plane value. The deposition-last process may be a promising way to achieve ultra-high density patterned media.

• 상하수도학회지
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• 제31권2호
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• pp.141-148
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• 2017

The waterworks company is in charge of managing water facilities buried underground, and the management has been centered on manholes. However, since there is no standard management manual, it has been impossible to introduce and operate a systemized managing tool by water service providers and managers, and manhole management has been carried out by individual data recording personnel for each water service provider. When the management is carried out individually, the data to be shared by other waterworks managers tend to be privatized, and consequently, it may become a big obstacle to proceed with many civil works such as emergency leak repair, road excavation, replacement of old buildings. This report introduces RFID (Radio Frequency Identification) system which is based on the magnetic field capable of IOT. It also describes the necessity of leveraging the system for smart managing of pipe management record that has been done by hand writing. The RFID system includes RFID marker, data reader, portable computer operating program, and data base server operating program. In this system, the data is managed with a single communication device, and it would be possible to share the information on the underground facilities and water treatment facilities. This RFID technology is expected to provide water service providers with opportunities to develop more scientific and modernized underground facilities information systems.

• Journal of Korean Neurosurgical Society
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• 제48권5호
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• pp.448-451
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• 2010

Primary central nervous system (CNS) sarcomas are exceedingly rare, and, to the best of our knowledge, there has not yet been a report of intramedullary sarcoma. Here, we report a primary intradural intramedullary sarcoma of the spinal cord in a four-year-old boy who presented with low back pain and a radiculopathy involving both lower extremities. The tumor showed significant enhancement on magnetic resonance (MR) images due to its extreme vascularity. Gross total tumor removal was performed with microelectrical pulse recording, and the patient also received adjuvant radiotherapy and chemotherapy. After the operation, the patient's sensory deficits were improved. Because CNS dissemination is common, entire neuraxis evaluation is essential, although there was no evidence of dissemination in this case. The prognosis of primary CNS sarcoma is poor due to infiltrative nature and early CNS dissemination is common, and the treatment of choice is radical surgical resection. Adjuvant therapy is also beneficial with radiotherapy and chemotherapy.

• 한국재료학회지
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• 제4권2호
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• pp.233-240
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• 1994

Pt/Co인공격자다층막($[Pt10.7\;{\AA}/Co2.8\;{\AA}]{\times}12$)의 자기특성 및 기록특성이 시료제작시의 조건 (sputtering gas압력, sputtering gas 종류, buffer층의 유무 및 etching)에 따라 어떻게 변화하는지를 알아보았다. Pt/Co다층막의 자기특성은 Tb-Fe-Co계 아몰퍼스재료와 거의 동등한 특성이 얻어졌으며 이다층막을 이용한 광자기디스크의 기록특성은 kerr회전각, 1.23도, 기록 power 특성, 36dB(레이저파장: 780nm)을 나타내어 Pt/Co다층막이 차세대광자기디스크용 재료로서의 실용화가능성을 보여주었다.