• Journal of Broadcast Engineering
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• v.16 no.1
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• pp.96-107
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• 2011

Recently, studies of 3D HDTV broadcasting technology have been processed actively. Korea is making efforts to modify Advanced Television Systems Committee (ATSC) 8-Vestigial Side Band (8-VSB) systems for terrestrial 3D HDTV broadcasting services. We intend to adopt a new frame structure to use PN (Pseudo-Noise) sequence as frame header, and VSB modulation. PN sequence is used to recover carrier freqeuncy offset, carrier phase error. In this paper, we will describe this system as the modified ATSC systems. The receiver of the modified ATSC system should be able to estimate and recover carrier frequency offset exactly. A existing ATSC systems inserts pilot to recover carrier frequency offset, on the other hand the modified ATSC systems use PN sequence to recovery carrier frequency offset without the use of pilot. In this paper, we introduce carrier frequency recovery (CFR) scheme for the modified ATSC systems. The proposed CFR scheme is composed of coarse CFR scheme using Fitz algorithm and fine CFR scheme using a simple PN sequence correlation algorithm. And, the symbol information of QAM modulated signal is contained in both In-phase (I)channel and Quadrature-phase (Q)channel. However the symbol information of VSB modulated signal is contained in I channel, and Q channel is just Hilbert transform of I channel. For the reason, VSB modulated symbols can not have fixed phase like QAM modulated symbols, and VSB modulated symbols is more sensitive to carrier frequency offset. Therefore we perform phase correction of received PN sequence to improve performance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.127-135
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• 2010

In motion adaptive temporal noise reduction filtering used for reducing video noises, the strength of motion adaptive temporal filtering should be carefully controlled according to temporal movement. This paper presents a motion adaptive temporal filtering scheme based on least-square training. Each pixel is classified to a specific class code according to temporal movement, and then, an iterative least-square training method is applied for each class code to find optimal filtering coefficients. The iterative least-square training is an off-line procedure, and the trained filter coefficients are stored in a lookup table (LUT). In actual noise reduction filtering operation, after each pixel is classified by temporal movement, simple filtering operation is applied with the filter coefficients stored in the LUT according to the class code. Experiment results show that the proposed method efficiently reduces video noises without introducing blurring.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.40-47
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• 2009

A motion adaptive video noise reduction scheme is proposed by cascading a temporal filter and a spatial filter. After a noise-robust motion detection is performed with a pre-spatial filter, the strength of the motion adaptive temporal filter is controlled by the amount of temporal movement. In order to fully utilize the temporal correlation of video signal, noisy input image is processed first by the temporal filter, therefore, image details of temporally stationary region are quite well preserved while undesired noises are suppressed. In contrast to the pre-spatial filter used for the robust motion detection, the cascaded post-spatial filter removes the remained noises by considering the strength of the temporal filter and the spatial self-similarity search results obtained from the pre-spatial filter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.246-249
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• 2005

The TFT-LCD is extensively used from a small watch to a large TV display, and the demand is increasing rapidly. The size of R-LCD glass plate becomes more bigger, and the thickness become more thinner with high demands. As a result natural frequency of the TFT-LCD glass plate becomes more lower. The TFT-LCD glass plate will be moved by robot arm and may receive effect of vibration that occur at transfer. Natural frequency of the TFT-LCD glass plate is increased or decrease according to location that robot arm fixs glass plate. Purpose of a this study is finding support location that optimize the first natural frequency of TFT-LCD glass plate. The size optimization method of ANSYS 8.0 is used as the optimization tool search on the optimal support location of TFT-LCD glass plate. The considered number of support point is from 4 to 9.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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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.

• Journal of Broadcast Engineering
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• v.21 no.6
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• pp.899-912
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• 2016

In ATSC 3.0 systems, a bootstrap signal is located at the start of each frame. In this paper, we propose an initial synchronization scheme for ATSC 3.0 systems using the bootstrap signal. The bootstrap signal of ATSC 3.0 has several repetition patterns in the time domain. By utilizing the repetition patterns within the bootstrap, the proposed scheme can obtain an initial synchronization at the receiver. Also, simulation results show that the proposed scheme can obtain an initial synchronization at very low signal-to-noise ratios.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.848-851
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• 2007

Recently, as the demand of the information storage devices with large storage capacity such as BD(Blu-ray Disk) and HDTV(high-definition television) is increased, the optical storage devices are also required to have fast data transfer rate and large storage capacity. To satisfy these requirements, the actuator for optical disk drive should have high flexible mode frequencies for system stability. In this paper, we suggested a moving magnet type actuator having high flexible mode frequency. However, the moving magnet type actuator does not have sufficient driving sensitivities due to the weight of its moving part. To improve driving sensitivities, we designed the model with the closed electromagnetic circuit for tracking direction. In addition, driving sensitivities and flexible mode frequencies were improved by using DOE(Design of Experiments) for magnetic circuit and modifying the lens holder. Consequently, it is confirmed that the designed model is satisfied with the desired specifications.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.463-464
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• 2008

As the demands of LCD and PDP TV are increasing, the high performance HVICs(High Voltage Gate Driver ICs) technology is becoming more necessary. In this paper, we designed the HVIC that has enhanced noise immunity and high driving capability. It can operate at 500KHz switching frequency and permit 600V input voltage. High-side level shifter is designed with noise protection circuit and schmitt trigger. Therefore it has very high dv/dt immunity, the maximum being 50V/ns. The HVIC was designed using $1{\mu}m$ BCD 650V process and verified by Spectre and PSpice of Cadence inc. simulation.

• Child Health Nursing Research
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• v.4 no.2
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• pp.265-273
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• 1998

The purpose of this study was to identify the children's sleeping patterns, such as the sleeping hours and the nature of sleep disruptions following hospitalization and its accompanying factors. The data were collected from December, 1997 to March, 1998 using a questionnaire developed by researchers. The subjects were 76 children in a hospital. The results of this study were summarized as follows : 1. The average sleeping hours (sleep duration) at night were 10 hours and 10 minutes and 9 hours and 9 minutes before and after hospitalization respectively. There was a significant difference (p<0.01). The average sleeping hours in the day time were 1 hour 28 minutes and 2 hours and 26 minutes before and after hospitalization respectively. There was a significant difference(P<0.01). 2. The mean bed time(sleep onset) was 10: 22 pm and 10 : 28 pm before and after hospitalization respectively. There was no significant difference. 3. The mean hour of rising(sleep termination) was 7: 54 am 7 : 08 am before and after hospitalization respectively. There was a significant difference (p<0.01). 4. The mean number of sleep disruption was 0.72 and 1.94 before and after hospitalization respectively. There was a significant difference(P<0.01). The sleep disruptions were influenced by crying of other children(53.9%), lights(28.9), nursing procedures(18.4%), noise of TV(17.l%) and noise of visitors (15.8%).

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.95-98
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• 2006

본 논문의 목표는 지상파 디지털 방송과 데이터 방송 그리고 아날로그 방송을 수신할 수 있는 DTV Set를 구현하고 일체형 디지털 방송 수신기에서 아날로그 방송과 영상을 입력받았을 때 화질저하의 원인이 되는 De-interlace 알고리즘과 3-D Noise를 적절하게 제거할 수 있는 알고리즘에 관한 연구가 목표이다. 또한, 디지털방송의 수신된 컨텐츠를 다른 저장매체로 불법적으로 복사, 재생을 막기 위한 디지털 컨텐츠복사를 방지할수 있는 알고리즘에 관한 연구이다. 현재, 우리나라에서는 기존의 아날로그 방송과 고품질 디지털 방송 서비스를 위한 디지털 방송이 시험적으로 실시되고 있는 상황이다. 이러한 환경하에서 디지털 방송 수신만을 위한 수신기는 아직 시기상조이며 아날로그 방송과 디지털 방송을 동시에 수신할 수 있는 일체형 수신기가 필요한다. 일체형 수신기에서 가장 문제가 되는 부분이 아날로그 방송을 수신하여 디지털 영상으로 인코딩한 후 화면에 뿌려 줄 때 Even Field와 Odd Field를 분리하여 뿌려주기 때문에 많은 영상의 열화가 발생하게 된다. 이러한 문제를 해결하기 위한 많은 방법들이 연구되고 있는 실정이다. 본 연구에서 사용된 시스템을 간략하게 소개하면 디지털 방송 수신을 위한 SoC 로는 Zoran의 G9 Ellete 채택하였고 아날로그 영상의 Decoder로는 AMI의 ADV7401을 선택하였다. 이에 대한 Operating System는 Real-Time OS인 Thread-X를 선택하였다.