• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 춘계학술대회
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• pp.98-100
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• 1991

A sensitive surface acoustic wave (SAW) sensor for the detection of odorants has been constructed by depositing different phospholipids and fatty acids on the surface of the SAW device wi th the Langmuir-Blodgett technique. The characteristics of SAW device operating at 310 MHz deposited with phosphatidylcholine were analyzed. Amyl acetate, acetoin, menthone and other organic gases showed different affinities. The identification of odorants depending on the species of lipid used for coating is discussed in terms of the similarity of the normalized resonant frequency shift pattern. Using a number of different lipid-coated SAW devices, odorants could be identified by a neural-network pattern recognition with back-propagation algorithm.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.1313-1317
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• 2006

In this study, various hydraulic phenomena were analyzed from the dam model experiments and the analyzed results were compared with existing computation results. Sungduk dam model structures were constructed using Froude similarity law by 1:50 scale. From the measurements of hydraulic phenomena at spillway channel, an improvement method was trying to be suggested over shortcoming of existing design plan. The result of model experiment showed no big difference with that of each part's numerical interpretation. Sidewall overflows were observed, as water conveyance occurred due to the linear characteristics of spillways, which raised the necessity for improving the linear forms of spillways. Also, it was judged to be necessary improving load pressure and establishing protective structures at the riverbed grounds of downstream channels.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2010년도 하계학술대회
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• pp.400-403
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• 2010

본 논문에서는 디지털 카메라의 자동초점 속도를 향상시키는 새로운 기법을 제안한다. 제안된 방식은 위상차 검출 방식에서 사용되는 추가적인 자동초점 모듈을 장착하지 않으면서도 빠르게 초점이 맞는 위치의 거리와 방향을 계산할 수 있는데, 이는 이중 분할 조리개를 이용하여 위상차가 발생하도록 하고, 컬러 필터를 이용하여 분리함으로써 소프트웨어 영상 처리만으로 위상차를 측정하여 정확한 초점 위치를 찾을 수 있기 때문이다. 이중 분할 조리개에 의해서 발생한 컬러 영상 채널 간의 상이한 정도를 측정하기 위하여 초점이 맞는 정도를 수치화 할 수 있는 유사도 측정 기준을 제시하는데, 이 기준으로 측정된 유사도를 비교함으로써 불일치 정도를 추출하며 정확한 초점을 잡기 위한 거리와 방향을 계산한다. 실험에서는 상용 디지털 카메라를 개조한 프로토 타입에서 취득한 영상을 사용하여 제안한 방식의 유효성을 검증하였다.

• 지식경영연구
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• 제8권1호
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• pp.15-28
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• 2007

In the age where the Internet changes everything, even the earth has become flat. The boarders between nations, locations, times, and industries are not meaningful, and no single company can do the whole process well. Therefore, various types of 'Value network' and 'Relation web' emerge for moving first and learning fast. Both the relationship maturity model (RMM) proposed and the partnership management initiatives at SKT demonstrate that the concept is important, and that the final goal can be reached only through a series of critical outcome at each phase. In particular, recognizing as core infrastructures various online/offline channels, deep trust, and rich communications is an important finding for a successful relationship management. Also, related literatures suggest the following key factors to be influential in more than two phases: professionalism including expertise, similarity, channel infrastructure, trustful/trustworthy, and absorptive capacity. Based on these findings, future efforts need to be put on the research & development of related measurement and management tools. It is hoped that more dance with their partners through these efforts.

• Journal of the Optical Society of Korea
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• 제12권3호
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• pp.136-146
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• 2008

We proposed an adaptive steganography of an optical image using bit-planes and multichannel characteristics. The experiment's purpose was to compare the most popular methods used in optical steganography and to examine their advantages and disadvantages. In this paper we describe two digital methods: the first uses less significant bits(LSB) to encode hidden data, and in the other all blocks of $n{\times}n$ pixels are coded by using DCT(Digital Cosine Transformation), and two optical methods: double phase encoding and digital hologram watermarking with double binary phase encoding by using IFTA(Iterative Fourier Transform Algorithm) with phase quantization. Therefore, we investigated the complexity on bit plane and data, similarity insert information into bit planes. As a result, the proposed method increased the insertion capacity and improved the optical image quality as compared to fixing threshold and variable length method.

• 대한기계학회논문집B
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• 제29권3호
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• pp.306-313
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• 2005

The performance of a regenerative pump is affected by many parameters, especially blade shape of impeller, leakage flow in the clearance and head losses at the inlet & outlet. An impeller with J-shape blade was designed and 5 times scale up model was tested at similarity conditions to evaluate the performance. Performance variations with clearance change were executed. The amounts of leakage flow through the clearance were estimated using the one-dimensional leakage flow models and analysis. Main leakage flow is generated through the gap between the impeller and casing. The inlet & outlet head losses were also estimated. Such corrections are very important to evaluate the final performance of the impeller and pump. Cavitation test was also performed at 1,200 rpm. NPSH of the regenerative pump was obtained and growth of cavity within blades was visualized.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2088-2093
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• 2008

In this study, flow field measurement of the Pebble Bed Reactor(PBR) for the High Temperature Gas-cooled Reactor(HTGR) was performed. Large number of pebbles in the core of PBR provides complicated flow channel. Due to the complicated geometries, numerical analysis has been intensively made rather than experimental observation. However, the justification of computational simulation by the experimental study is crucial to develop solid analysis of design method. In the present study, a wind tunnel installed with pebbles stacked was constructed and equipped with the Particle Image Velocimetry(PIV). We designed the system scaled up to realize the room temperature condition according to the similarity. The PIV observation gave us stagnation points, low speed region so that the suspected high temperature region can be identified. With the further supplementary experimental works, the present system may produce valuable data to justify the Computational Fluid Dynamics(CFD) simulation method.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.361-366
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• 2003

For regenerative pump performance test we made 5 times enlarged and 3 different kinds blade types impeller with similarity. Due to geometrical characteristic of regenerative pump, there are two kinds of groups which effect on performance of it. One is geometric shape of impeller blade and the other is clearance and inlet/outlet head loss. To study performance of regenerative pump with impeller shape changes, we tested it with reducing clearance. And we reconcile performance data in the case of zero clearance and zero inlet/outlet head loss. Finally we could verify the influence of each group.

• 한국멀티미디어학회논문지
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• 제25권5호
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• pp.676-684
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• 2022

As realistic media are widespread in various image processing areas, image or video compression is one of the key technologies to enable real-time applications with limited network bandwidth. Generally, image or video compression cause the unnecessary compression artifacts, such as blocking artifacts and ringing effects. In this study, we propose a Deep Residual Channel-attention Network, so called DRCAN, which consists of an input layer, a feature extractor and an output layer. Experimental results showed that the proposed DRCAN can reduced the total memory size and the inference time by as low as 47% and 59%, respectively. In addition, DRCAN can achieve a better peak signal-to-noise ratio and structural similarity index measure for compressed images compared to the previous methods.

• 한국음향학회지
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• 제35권5호
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• pp.331-339
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• 2016

본 논문은 음선 기반 블라인드 디컨볼루션을 이용하여 송 수신기의 상대적인 이동으로 인한 도플러 편이가 존재하는 수중 음향 채널 환경에서의 송신 신호 및 채널 임펄스 응답 추정에 대한 방법을 제시한다. 도플러 편이가 존재하는 수중 채널 환경에서 m시퀀스와 같은 도플러 효과에 민감한 탐침 신호를 사용할 경우, 도플러 왜곡에 의한 수신 신호와의 낮은 상관도에 의해 정합 필터 처리만으로는 채널 임펄스 응답 추정에 어려움이 따른다. 본 연구에서는 음선기반 블라인드 디컨볼루션을 이용하여 도플러 편이가 포함되어 있는 송신 신호의 위상을 추정한 후, 이를 수신 신호에 보상함으로써 도플러 편이가 보상된 채널 임펄스 응답 추정에 대한 방법을 제안한다. 해상실험을 통해 측정된 수신 데이터에 대하여 정합 필터만으로는 채널 임펄스 응답 추정이 어려운 반면 제안된 방법을 통한 채널 임펄스 응답 추정 시, 음선 모델에서 예측된 전달경로와 유사한 특성을 보여주는 것을 확인하였다. 또한 산란 함수를 통해 추정된 도플러를 보상한 송신 신호에 비해 음선 기반 블라인드 디컨볼루션을 이용하여 복원한 송신 신호가 더 우수한 도플러 보상효과를 나타낸다.