• 한국통신학회논문지
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• 제21권8호
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• pp.2055-2062
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• 1996

This paper presents a method of compensating for the gain and phase imbalance of quadrature modulator and demodulator. The gain and phase imbalance are compensated using the received power after the compensation pattern was transmitted at tranceiver. The proposed method is less vulnerable to changes in the transmission channel than the conventional method because compensation is made possible within the tranceiver system, and even the change in phase mblance in accordance with frequency can be compensated utilizing the adaptive algorithm. According to numerical results, a normalized eye opening and a bit error rate are improved by 1.8dB and 3.8dB, respectively.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 추계학술발표대회
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• pp.705-707
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• 2016

본 연구는 e러닝 학습 환경에서 문제 풀이에 대한 전문가와 학습자 사이의 시선 흐름을 비교 분석하여 학습자에게 보다 효율적인 학습 방법을 제시 할 수 있는 데이터를 추출하는 데 목적이 있다. 연구를 위해 빛의 투과율이 적은 장소의 PC에 웹캠을 설치하였고, 학습 화면의 해상도는 $1600{\times}900$로, 3명의 전문가와 5명의 학습자를 통하여 10문항에 대한 시선 추적으로 학습 데이터를 축적하였다. 축적한 데이터를 통하여 고득점 학습자나, 전문가의 학습 방법을 비교하여 유사도를 측정하였고, 유사도에 따라 학습 유형을 추천해 줄 수 있는 가능성을 확인하였다.

• Journal of Information Display
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• 제11권2호
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• pp.63-67
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• 2010

In these authors’ previous paper, it was shown that grey-level stability is one of the main drawbacks of the time-sequential stereoscopic 3D display. In the present study, it was demonstrated that a videoluminance meter can be used to rapidly and easily check the quality of such display. A dedicated pattern was applied to simultaneously check the effect of the grey level on the other eye and the effect of the temporal synchronization. The results were compared with those provided by a temporal model of the display, which was obtained by measuring its temporal behavior. The visual impact of the grey-level instabilities was precisely quantified, and they were found to be a major source of imperfections for the aforementioned display.

• 한국어류학회지
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• 제9권1호
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• pp.108-113
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• 1997

한국산 농어의 형태적 특징을 조사하여 농어 Lateolabrax japonicus를 재 기재하고 농어와 분류학적으로 다른 집단 Lateolabrax sp.를 독립된 종으로 간주하여 잠정적으로 기재하고 국명으로는 점농어라 하였다. 점농어는 체측에 뚜렷한 반점이 있고 눈이 크고 새파수가 적으며 2차 체고와 측선이 등쪽으로 구부러진 특징이 있다. 우리 나라 서 남해안에는 농어와 점농어가 혼서 한다.

• Journal of Ecology and Environment
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• 제29권5호
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• pp.425-432
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• 2006

The tadpoles of 12 Korean anuran species, including Bombina orientalis, Bufo gargarizans, B. stejnegeri, Hyla japonica, Kaloula borealis, Rana dybowskii, R. huanrenensis, R. coreana, R. nigromaculata, R. chosenica, R. rugosa, and R. catesbeiana, were classified based on their morphological characteristics. We collected eggs or tadpoles of the 12 Korean anuran species from Gangwon, Incheon, Chungcheong, and Gyeonggi districts in 2005 and 2006 breeding seasons. When the tadpoles reached at $27{\sim}37$ Gosner's developmental stages, we described morphological characteristics of the tadpoles of each anuran species and measured their physical parameters such as total length, body length, and body mass. After that, we chose 12 morphological characteristics to identify each species and to use them as classification keys such as eye location, caudal musculature pattern, spiracle location, oral disc morphology, and labial tooth row formula. In this paper, we presented classification keys, morphological characteristics, and drawings for the tadpoles of 12 anuran species.

• 치과방사선
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• 제4권1호
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• pp.63-67
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• 1974

The authors have observed a rare case of neurofibroma in 13 years old male who came to the Infirmary of Dental College of Seoul National University because of painless severe swelling of approximately 11 years' duration in the left maxillofacial region and blindness of the left eye about 3 years' duration. As a result of interpretating the serial roentgenograms including tomograms and microscopic findings, we have obtained the following conclusions; 1. Neurofibroma of the patient occurred in about 2 years of age. 2. The familial tendency of the disease has been noted. 3. The growth pattern of the disease was slow, and roentgenographic images revealed severe destruction of bone with irregular borders. 4. The neurofibroma was encapsulated but Verocay body and palisading effect of cells were not seen in the microscopic picture.

• 반도체디스플레이기술학회지
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• 제15권3호
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• pp.6-11
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• 2016

Silicon wafer is one of main materials in solar cell. Micro-cracks in silicon wafer are one of reasons to decrease efficiency of energy transformation. They couldn't be observed by human eye. Also, their shape is not only various but also complicated. Accordingly, their shape classification is absolutely needed for manufacturing process quality and its feedback. The performance of typical classification techniques which is principal component analysis(PCA), neural network, fusion model to integrate PCA with neural network, and support vector machine(SVM), are evaluated using pattern features of micro-cracks. As a result, it has been confirmed that the SVM gives good results in micro-crack classification.

• Journal of the Optical Society of Korea
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• 제14권3호
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• pp.266-276
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• 2010

In the present study, an optical system is proposed for maskless lithography using a digital micromirror device (DMD). The system consists of an illumination optical system, a DMD, and a projection lens system. The illumination optical system, developed for 95% uniformity, is composed of fly's eye lens plates, a 405 nm narrow band pass filter (NBPF), condensing lenses, a field lens and a 250W halogen lamp. The projection lens system, composed of 8 optical elements, is developed for 4 ${\mu}m$ resolution. The proposed system plays a role of an optical engine for PCB and/or FPD maskless lithography. Furthermore, many problems arising from the presence of masks in a conventional lithography system, such as expense and time in fabricating the masks, contamination by masks, disposal of masks, and the alignment of masks, may be solved by the proposed system. The proposed system is verified by lithography experiments which produce a line pattern with the resolution of 4 ${\mu}m$ line width.

• 한국통신학회논문지
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• 제17권9호
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• pp.963-971
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• 1992

본 논문에서는 (4.6) 블록의 새로운 2진 선로부호를 제안하였다. 제안된 2진 선로부호 MB46은 무직류 (DC-Free) 성질 및 유한연속장(runlength limited) 성질을 만족할 뿐만 아니라 대역폭이 나이퀴스트 주파수로 제한되므로 이제까지 알려진 2진 선로부호들 보다 대역폭 효율이 개선된 부호이다. 제안된 부호의 설계에 특별히 적용된 설계기법을 심도있게 설명하였으며, 성능 측정의 일환으로 시뮬레이션을 통하여 MB46의 눈 모양 및 전력스펙트럼을 나타내었다.

• 한국통신학회논문지
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• 제17권10호
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• pp.1074-1080
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• 1992

새로운 (5.8)블록 2진 선로부호를 제안하였다. 제안된 선로부호 MB58은 무직류(DC-free)성질 및 유한 연속장(runlength limited) 성질을 만족할 뿐만아니라, 대역폭이 나이퀴스트 주파수로 제한되므로 대역폭 효율이 개선된다. 또한 이 부호는 memoryless 부호이고, 오류 발생을 검출해 낼 수 있는 장점이 있으며 복호규칙이 간단하다. 제안된 선로부호에 대한 전력스펙트럼에서 DC(f=0)및 나이퀴스트 주파수(f=1/2Ts)에서 전력 영점이 존재함을 시뮬레이션을 통해 확인하였으며 눈 모양의 시뮬레이션을 통해 눈이 충분히 크게 됨을 확인하였다.