• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.572-572
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• 2013

본 연구에서는 Plasma damage-free 선형 대향 타겟 스퍼터(Linear Facing Target sputtering: LFTS) 시스템을 이용하여 성막시킨 GaN-LED의 투명전극용 Ga-doped ZnO (GZO) 박막의 특성을 연구하였다. LFTS 시스템을 이용한 GZO 성막 공정 중 LED소자의 플라즈마 노출에 의한 데미지를 최소화 하기 위해 일정한 타겟간 거리(Target-to-Target distance: 65 mm)에서 타겟과 기판간 거리(Target-to-Substrate distance)를 50 mm에서 120 mm로 변화시키며 GZO 투명 전극을 성막해 박막의 특성과 소자의 특성을 동시에 분석하였다. LFTS에서 플라즈마는 GZO 타겟 사이에 형성된 일방향의 자장에 의해 효과적으로 구속되기 때문에 기판과 타겟 거리를 최적화 할 경우 플라즈마 데미지를 최소화하며 GaN-LED의 제작이 가능하다. 기판과 타겟 사이의 거리가 120 mm에서 최적화된 200 nm 두께의 GZO 투명 전극은 DC 파워 250 W, 공정 압력 0.3 mTorr, Ar 20 sccm 실험 조건하에서 LED 소자 위해 성막되었으며, 이후 $600^{\circ}C$ 수소 분위기에서 1분간 급속 열처리하였고 면저항(37 Ohm/sq.)과 450 nm 파장에서의 투과도(83%)를 나타냄을 확인할 수 있었다. LED 소자와 타겟 사이의 거리가 50 mm에서 120 mm로 증가할수록 성막공정 중 LED 소자에 미치는 플라즈마 데미지의 감소로 인해 GaN-LED 소자의 turn on voltage가 8.2 V에서 3.4 V로 감소한 것을 확인하였으며, 또한 radiant intensity는 20 mA의 전류를 인가하였을 시 0.02 mW/sr에서 8 mW/sr로 400배 향상되었다. 이러한 소자 특성은 대향 타겟 스퍼터 시스템으로 성장시킨 GZO 투명전극이 LED 소자의 투명 전극 층(Transparent Conductive Layer: TCL)에 적용될 수 있음을 말해준다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.3
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• pp.71-79
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• 2003

Existing web-based system management software solutions show some limitations in time and space. Moreover, hey possess such as shortcomings unreliable error message announcements and difficulties with real-time assistance supports and emergency measures. In order to solve these deficiencies, Wireless Remote Control System(W-RCS) was designed and implemented. W-RCS is able to manage and monitor remote systems by using mobile communication devices for instantaneous control. The implementation of W-RCS leads to these security problems as well as solutions to aforementioned issues with existing web-based system management software solutions. Therefore, this paper has focused on the security matters related to W-RCS. The security functions based on public key infrastructure include mobile device user authentication and target system access control. The W-RCS allows real-time user authentication, increases the flexibility of resource administrators and mobile device non, and provides not only uninterrupted services, but also safe mobile office environments.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.311-316
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• 2001

This study analyzed the influence of paste fluidity and vibration time for fundamental properties of porous concrete. Results of this study were shown as follows; 1) Even if target void ratio is same, void ratio and compressive strength of porous concrete is different according to w/c, paste flow and vibration time. So, In case of target void ratio, we must consider the influence of w/c, paste flow, and vibration time. 2) Though w/c and vibration time are same, as paste flow increase, all void ratio, continuous void ratio, and compressive strength decrease and difference between upper and lower void ratio increase. 3) Though w/c and paste flow are same, as vibration time increase, all void ratio and continuous void ratio decrease and difference between upper and lower void ratio increase. Also, compressive strength increase by 10 seconds and decease after 10 seconds. 4) As types of superplasticizer is different, all void ratio, continuous void ratio, and compressive strength are different. So, we must give consideration to paste fluidity and vibration time in order that increase of strength of porous concrete and distribution of uniform void.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.11-14
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• 2018

The aim of this study is to rectify the misclassified image features and enhance the performance of image classification tasks by incorporating a channel- coding technique, widely used in telecommunication. Specifically, the proposed algorithm employs the error - correcting mechanism of convolutional coding combined with the convolutional neural networks (CNNs) that are the state - of- the- arts image classifier s. We develop an encoder and a decoder to employ the error - correcting capability of the convolutional coding. In the encoder, the label values of the image data are converted to convolutional codes that are used as target outputs of the CNN, and the network is trained to minimize the Euclidean distance between the target output codes and the actual output codes. In order to correct misclassified features, the outputs of the network are decoded through the trellis structure with Viterbi algorithm before determining the final prediction. This paper demonstrates that the proposed architecture advances the performance of the neural networks compared to the traditional one- hot encoding method.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.107-114
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• 2023

X-ray fluorescence analysis has been widely used in the field of science and industry because it gives information about elements and their concentrations without destruction of samples. To increase analysis accuracy of fluorescence generated by photons of the transmission-type X-ray tube for mixture and compound samples would be recommend to have strong energy near 10 keV and 20 keV simultaneously. Tungsten of 9.65 keV and molybdenum of 17.48 keV were considered as targets with dual deposition structure for obtaining two strong characteristic X-rays, and the transmission-type X-ray tube was analyzed using Geant4 Monte Carlo simulation. The W-Mo structure resulted in strong characteristic X-ray near 10 keV and 20 keV simultaneously. A structure with Mo-W multilayers of 5 ㎛ thick also gave optimal spectrum. Various material combination and thickness optimization for the dual-structured target can give X-ray spectrum with strong characteristic X-ray of specific energies.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.209-209
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• 1999

현재 magnetron sputter는 반도체, LCD 등을 포함하는 microelectronics 산업에서 박막형성을 위한 주요 장비로 널리 쓰이고 있으며, 소자의 고집적화 및 대형화 추세에 따라 그 이용가치는 더욱 증대되고 있다. 본 연구엣는 TFT-LCD용 Color Filter 제조시 ITO박막형성을 위해 사용하는 magnetron sputter 내부의 플라즈마 분포 및 ion kinetic energy에 대한 해석을 실시하였으며, ITO target의 erosion 형상의 원인을 실험결과와 비교하였다. Magnetron sputtering은 target에 가해지는 bias 전압(DC 혹은 RF)에 의해 target과 shield 혹은 target과 substrate 사이에서 생성될 수 잇는 플라즈마를 target 및 부분에 붙어있는 영구자석을 이용하여 target 근처에 집중시키고, target 표면과 플라즈마 사이의 전위차에 의해 가속된 이온들이 target 표면과 충돌하여 이차 전자방출을 일으킴과 동시에 target 표면에서 sputtering을 일으키고, 이들 sputtered 된 중성의 atom 들이 substrate로 날아가 박막을 형성하는 원리로 작동된다. 이때 target에서 방출되는 이차전자들은 영구자석에 의한 자기장 효과에 의해 target 근처에 갇히게 되어 중성 기체분자들과 이온화반응을 통해 플라즈마를 유지하고 그 밀도를 높혀주는 역할을 담당하게 된다. 즉 낮은 압력 및 bias 전압에서도 플라즈마 밀도를 높일수 있고 sputtering 공정이 가능한 장점을 가지고 있다. Magnetron sputtering 현상에 대한 시뮬레이션은 크게 magnetron discharge와 sputtering에 대한 해석 두가지로 나누어 볼 수 있는데, sputtering 현상 자체를 수치묘사할 수 있는 정량적인 모델은 아직까지 명확하게 정립되어 있지 않다. 따라서 본 연구에서는 magnetron plasma 자체에 대한 수치해석에 주안점을 두고 아울러 bulk plasma 영역에서 target으로 입사하는 이온들의 입사에너지 및 입사각도 등을 Monte Carlo 방법으로 추적하여 sputtering 현상을 유추해보았다. Sputtering 현상을 살펴보기 위해 magnetron sputter 내 플라즈마 밀도, 전자온도, 특히 target 및 substrate를 충돌하는 이온의 입사에너지 및 입사각 분포등을 계산하는데 hybrid 방법으로 시뮬레이션을 하였다. 즉 ion과 bulk electron에 대해서는 fluid 방식으로 접근하고, 이차전자 운동과 그로 인한 반응관계 및 target으로 입사하는 이온의 에너지와 입사각 분포는 Monte-Carlo 방법으로 처리하였다. 정지기장해석의 경우 상용 S/W인 Vector Fields를 사용하였다. 이를 통해 sputter 내 플라즈마 특성, target으로 입사하는 이온에너지 및 각 분포, 이들이 target erosion 형상에 미치는 영향을 살펴보았다. 또한 이들 결과로부터 간단한 sputtering 모델을 사용하여 target으로부터 sputter된 입자들이 substrate에 부착되는 현상을 Monte-Carlo 방법으로 추적하여 성막특성도 살펴보았다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.06a
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• pp.31-36
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• 1997

Bit allocation is a critical problem in video encoding such as MPEG. To improve the quality of the reconstructed sequence for a given bit rate, the assigned target bits for a group of pictures (GOP) must be allocated to each picture efficiently. In this paper, we derive a target bit allocation algorithm for more efficient rate control, by assuming that the average rate-distortion curve for an input source is logarithmic. This target bit allocation is based on Shannon's rate-distortion theory, which deals with the minimization of source distortion subject to a channel rate constraint. Simulation results show that the proposed target bit allocation algorithm provides better performance than the one in MPEG-2 Test Model 5 (TM5).

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.288-291
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• 2006

The authors, R&D member of DAWONSYS and Soongsil University, are developing 5000kW smelting inverter system by 2007 under the sponsor from Korea Energy Management Corporation. As a part of the project, 2500kW inverter system has developed in 2005[6], and installed in real production site, and has been running for 7 months successfully. This report deals with the test result of 2500kW smelting inverter system and design for 5000kW smelting inverter system which is final target of this project.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.445-450
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• 2009

One method to improve quality before releasing of S/W after development is to enhance the reliability, whose direct methodology is to detect and revise fault through testing. Once the S/W is released because it meets the target reliability, the operational reliability problem arises. It is obvious the operational reliability different from that of testing stage depending on the condition whether it is universal(package) S/W or dedicated S/W. I propose the methodology to calculate operational software reliability of universal and dedicated S/W in this paper.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.417-422
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• 2007

In this study, we investigated spatio-temporal eye-hand coordination by the "Global effect paradigm", a target-distracter configuration Global effect is observed a variety of visual tasks, for example, during rapid automatic tracking, scanning for target detail, and the comparison of target configurations. Global effect used to investigate eye-hand coordination with a task that presents a target close to a distracter. Eight young subjects participated in the experiments. The experiments consist of using a distracter less eccentric than the targe1 and using a distracter more eccentric than target. Each experiment consist of tasks which are making reference, pointing the target with watching visual stimulation(saccade) and pointing the target. The subject's task was to move towards the target as quickly as possible. We measured the eye movement by using EOG and the hand movement by using NDI Optotrak system. This study shows that eye and hand movement exists for global effect paradigm in spatio-temporal coordination.