• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.511-513
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• 2004

위성의 부분체 또는 탑재컴퓨터 및 탑재소프트웨어에 대한 검증시험을 수행하기 위해서는 위성개발에 사용하며 그 기능이 검증된 상용프로그램을 사용하는 것이 일반적이다. 그러나 위성 영령의 전송 및 텔레메트리 데이터의 전송과 분석을 위한 프로그램은 위성에 사용되는 종류 및 포맷에 따라 다양한 형태로 수정되어야 하기 때문에 자체 제작한 프로그램을 사용하게 된다. 99년에 발사되어 성공적으로 임무를 수행하고 있는 다목적실용위성 1호 및 현재 개발이 진행 중인 다목적실용위성 2호의 개발과정에서는 LEX와 YACC이라는 구문분석기를 이용한 VTSP(Verification Test Script Parser) 프로그램이 탑재소프트웨어의 검증시험에 사용되었다. VT5P는 실시간 데이터 전송 및 분석이 가능하지만 UNIX 환경에서만 실행되므로 윈도우 환경에서 작업하던 일반 사용자들에게는 익숙하지 않은 시험환경을 제공하여 텍스트 기반의 작업이 필요하므로 시험 수행에 여러 어려움들이 발생한다. 이러한 단점들을 보완하기 위하여 윈도우 기반의 검증시험 프로그램인 SATS(Spacecraft Automatic Test Script)를 개발하였다. 본 논문에서는 대부분의 사용자들에게 익숙한 윈도우 환경을 제공하며 이더넷을 통하여 장소에 상관없이 다중의 개발자가 시험을 수행할 수 있는 SATS의 개발현황과 수행환경에 대하며 소개한다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1429_1430
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• 2009

본 연구에서는 7인치 샘플패널의 가속 Aging 실험을 통해 Aging time(24hr~529hr)변화에 따른 오방전 발생 Mechanism을 분석하고자 했다. 상온에서 Aging time변화에 따른 정마진, 휘도, Vt close curve를 측정 하였고 시간과 온도(고온: $70^{\circ}C$, 상온: $25^{\circ}C$, 저온: $-20^{\circ}C$)에 따른 Discharge time lag의 변화양상을 측정하였다. 그리고 Sustain pulse수의 조절을 통해 패널의 Priming 조건을 제어하면서 오방전 발생 확률을 수치적으로 측정하였다. 실험을 통해, 패널의 Aging time이 늘어남에 따라서 상판의 MgO층에서 Sputtering현상이 발생하여 MgO 잔재들이 하판의 형광체 표면을 덮는 등 방전 개시 전압의 변화가 오방전 발생에 주요한 원인임을 알 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.310-310
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• 2013

본 연구에서는 Titanium (Ti) source/drain 전극 접합이 차세대 비정질 InGaZnO (IGZO) 기반 박막형 트랜지스터에 미치는 영향을 화학적, 구조적, 전기적 특성 분석을 통하여 관찰하고 Ti/IGZO 접합 특성을 설명할 수 있는 메커니즘을 제시하였다. IGZO 기반 박막형 트랜지스터 소자의 구동 특성은 transmission line method (TLM) 패턴 공정을 이용하여 정량적으로 분석되었다. 비정질 IGZO 기반의 박막형 트랜지스터에서 Ti source/drain 전극 접합에 의한 구동 특성 변화 및 영향을 확인하기 위하여 금속/산화물 계면 반응성이 낮은 silver (Ag) source/drain 전극이 reference로 비교되었으며, 그 결과 Ti source/drain 전극 접합이 적용된 비정질 IGZO 트랜지스터의 경우 Ti 금속과 IGZO 산화물 계면에 형성되는 열역학적으로 안정한 $TiO_x$ 층의 형성에 의해 VT ($-{\Delta}0.52V$) shift 및 saturation mobility ($8.48cm^2$/Vs) 상승됨을 확인하였다. 뿐만 아니라 TLM 패턴을 이용한 IGZO 트랜지스터의 전기적 변수 도출 및 수치적 해석으로부터 $TiO_x$ 계면층 형성이 Ti 금속과 비정질 InGaZnO 계면에서의 effective contact resistivity를 효과적으로 낮출 수 있음을 확인하였다. Ti source/drain 전극 접합에 의해 발생되는 $TiO_x$ 계면층의 화학적, 구조적 특성과 $TiO_x$ 계면층 생성에 의한 소자 특성 변화를 연관시켜 해석함으로써, IGZO 기반 박막형 트랜지스터에서의 Ti source/drain 전극 접합이 비정질 IGZO 기반 박막형 트랜지스터에 미치는 영향을 설명하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.41-47
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• 2009

The power IT project "Development of Prototype for Advanced Substation Automation System based on the Digital Control Technology", is going on how to perform the verification of a IEC 61850 based Merging Unit for development of the full Substation Automation system from station bus to process bus. the testing method that this paper suggests, is including the conformance testing of IEC 61850 communication services and transmission functions of digital sampled values such as current and voltage, and referring to IEC 61850 conformance testing of IED. And finally, the paper shows a test system for the Merging Unit.

• The Journal of the Acoustical Society of Korea
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• v.31 no.1
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• pp.39-50
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• 2012

A voice transformation (VT) method that can make the utterance of a source speaker mimic that of a target speaker is described. Speaker individuality transformation is achieved by altering three feature parameters, which include the LPC cepstrum, pitch period and gain. The main objective of this study involves construction of an optimal sequence of features selected from a target speaker's database, to maximize both the correlation probabilities between the transformed and the source features and the likelihood of the transformed features with respect to the target model. A set of two-pass conversion rules is proposed, where the feature parameters are first selected from a database then the optimal sequence of the feature parameters is then constructed in the second pass. The conversion rules were developed using a statistical approach that employed a maximum likelihood criterion. In constructing an optimal sequence of the features, a hidden Markov model (HMM) was employed to find the most likely combination of the features with respect to the target speaker's model. The effectiveness of the proposed transformation method was evaluated using objective tests and informal listening tests. We confirmed that the proposed method leads to perceptually more preferred results, compared with the conventional methods.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.6
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• pp.696-707
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• 1988

This study simulates a typical solar system using the transient simulation program TRNSYS, and calculates the maximum cooling load of the model room of $50m^2$. In this study, energy rate control method is used in calculating a maximum cooling load. On the ground of the maximum cooling load of the model room, the variables that have an effect on the solar collection performance of the solar system are made a selection. Also in this study the trend of the solar collection performance is shown as the variables change. The results show that the variables which have an effect on the collection performance are collector area, collector mass flow rate, collector slope and the volume of storage tank, and the optimal value of Ac/Vt is not constant but varies as the collector area and the collector mass flow rate. Also the results show that for cooling system the optimal value of the collector slope is latitude minus $15^{\circ}$ during the seasonal operations, and twenty percent of the maximum cooling load is saved with the aid of the solar energy.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1617-1620
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• 2008

The effects of the temporal and permanent bright image stickings were examined under variable panel working gas pressure in the 42-in. ac-PDP with a high Xe (11 %) content. In the cells with and without temporal and permanent bright image stickings, the display luminance, firing voltage, and Vt closed curve were measured relative to the working gas pressure. With a decrease in the working gas pressure, the temporal bright image sticking was observed to be reduced, whereas the permanent bright image sticking was observed to be deteriorated.

• Journal of Oriental Neuropsychiatry
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• v.9 no.1
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• pp.59-71
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• 1998

The effect of Samyonjihwangtang(SJT) on th level of brain antioxidants was examined in aged rat. Samyongjihwangtang(SJT) is assed Cervi Pantiri-chum Cornu, Ginseng Radix to Yukmijihwangtang. The experimental groups were divided into three groups and treated as follows ; normal group(NC), Vt.E administrated group(PC), SJT administrated Group(SJT). From the purified microsome of brain tissue, those were measures the amounts of oxidant materials like malonaldehyde(MDA) and H_2O_2, then activities of antioxidants enxymes like Superoxide dismutase, Catalase, NADPH-cytochrome P-450 reductase.The results were as follows;1. In TBA reaction to measure the amount of MDA, oxidant material of brain tissue of aged rat, both treated groups showed significant decrease.2. In the formation of Hydrogen peroxide, the treated group(SJT) showed a little decrease.3. The activity of Superoxide dismutase was increased significantly in both treated groups than normal group.4. the activity of Catalase was increased significantly in both treated groups than normal group. 5. The activity of NADPH-cytochrome P-450 reductase in the treated group(SJT) showed a little increase.According to the above results, it is suggested that Samyongjihwangtag(SJT) has some antioxidant effects on the tissue of brain.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.3
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• pp.1047-1062
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• 2018

In this paper the problem of massive multiple input multiple output (MIMO) channel estimation with sparsity aware adaptive algorithms for $5^{th}$ generation mobile systems is investigated. These channels are shown to be non-stationary along with being sparse. Non-stationarity is a feature that implies channel taps change with time. Up until now most of the adaptive algorithms that have been presented for channel estimation, have only considered sparsity and very few of them have been tested in non-stationary conditions. Therefore we investigate the performance of several newly proposed sparsity aware algorithms in these conditions and finally propose an enhanced version of RZA-LMS/F algorithm with variable threshold namely VT-RZA-LMS/F. The results show that this algorithm has better performance than all other algorithms for the next generation channel estimation problems, especially when the non-stationarity gets high. Overall, in this paper for the first time, we estimate a non-stationary Rayleigh fading channel with sparsity aware algorithms and show that by increasing non-stationarity, the estimation performance declines.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.32-33
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• 2019

The purpose of this study are analyzing marine incident occurred in Busan VTS area, establishing standard of marine incident based on the data, and presenting the way to activate marine incident system. As implement this system, it is figured out that marine incident system could contribute to preventing similar accident, standing out role of VTS and improvement of VTS officer's ability. It includes efficiency of VTS marine incident and matters which necessary to implement this system.