• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.958-961
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• 1999

A new image encoding and identification scheme is proposed for security verification by using CGH(computer generated hologram), random phase mask, and correlation technique. The encrypted image, which is attached to the security product, is made by multiplying QPH(quadratic phase hologram) using SA(simulated annealing) algorithm with a random phase function. The random phase function plays a role of key when the encrypted image is decrypted. The encrypted image could be optically recovered by 2-f system and automatically verified for personal identification. Simulation results show the proposed method cand be used for the reconstruction and the recognition of the encrypted. Image.

• Journal of the Optical Society of Korea
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• 제13권1호
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• pp.92-97
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• 2009

In this paper, a conventional simulated annealing (SA) method for optimization of a kinoform computer generated hologram (CGH) is analyzed and the SA method is modified to reduce a reconstruction error rate (ER) of the CGH. The dependences of the quantization level of the hologram pattern and the size of the data on the ER are analyzed. To overcome saturation of the ER, the conventional SA method is modified as it magnifies a Fourier-transformed pattern in the intermediate step. The proposed method can achieve a small ER less than 1%, which is impossible in the conventional SA method.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.316-320
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• 2010

We report an application of full-field optical coherence tomography (FF-OCT) for identifying counterfeit bank notes. The depth-resolved imaging capability of FF-OCT was used for tomographic identification of superficially-identical objects. By retrieving the internal structures of the security feature (cash hologram) of an original banknote, we could demonstrate the feasibility of FF-OCT to identify counterfeit money. The FF-OCT images showed that the hologram consisted of micron scale multi-coated layers including an air gap. Therefore, it is expected that FF-OCT has potential as a new non-invasive tool to discern imitation of currency, and it would find applications in a wide field of counterfeit sciences.

• Journal of the Optical Society of Korea
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• 제4권1호
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• pp.19-22
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• 2000

A new image encoding and identification scheme is proposed for security verification by us-ing a CGH(computer generated hologram), random phase mask, and a correlation technique. The encrypted image, which is attached to the security product, is made by multiplying a QP- CGH(quadratic phase CGI) with a random phase function. The random phase function plays a key role when the encrypted image is decrypted. The encrypted image can be optically recovered by a 2-f imaging system and automatically verified for personal identification by a 4-f correlation system. Simulation results show the proposed method can be used for both the reconstruction of an original image and the recognition of an encrypted image.

• 한국정보통신학회논문지
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• 제8권4호
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• pp.838-845
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• 2004

실제 주민등록증을 스캐너로 수집한 후 해당 영상에 대하여 주민등록번호를 인식하였다. 인식을 위한 전처리 과정은 처리 속도를 감안하여 대상부분을 포함 주민등록증의 약 1/8 크기만큼 분할한 후 잡음에 해당하는 홀로그램을 제거하였다. 숫자 인식 방법으로는 원형비교법과 학습법을 병행하였으며 대상 숫자의 단순한 특징 추출을 위해 클러스터링 방식을 사용하였고, 외부 환경에 따라 오인식되는 숫자에 대해 세선화 기법을 병행하여 유사한 숫자간의 유일한 특징으로 구분하였다. 인식에 대한 실험 결과, 숫자 인식에 관한 타 논문의 인식률과 비교하여 양호한 인식률이 도출되었다.

• 한국안전학회지
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• 제14권4호
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• pp.204-210
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• 1999

본 논문에서는 정합필터의 데이터 베이스로 체적 홀로그램을 사용한 광 지문 인식 시스템을 제안하였다. VanderLugt 상관기에 사용되는 정합필터는 방대한 저장 능력과 실시간 랜덤 엑세스의 장점을 갖는 체적 홀로그램에 기록된다 데이터 베이스로 사용되는 지문 영상들은 각각 공간광변조기에 디스플레이 되어 퓨리에 변환 렌즈를 통과한 후 퓨리에 변환된 공간정합필터의 형태로 광굴절매질에 기록된다. 대용량의 데이터 베이스를 구성하기 위한 다중화 방법으로 스텝 모터를 이용하여 기준파의 각도를 회전하는 각다중화 기술을 사용하였다. 실험을 통해 본 시스템이 제한된 영역의 접근을 통제하기 위한 개인 인증용 안전 출입 시스템 및 크레디트카드, 여권, ID등의 위조방지에 이용이 가능함을 제시하였다

• 통합자연과학논문집
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• 제8권2호
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• pp.81-88
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• 2015

c-Jun N-terminal kinase-3 (JNK3) is a member of the mitogen-activated protein kinase family (MAPK), and plays an important role in neurological disorders. Therefore, identification of selective JNK3 inhibitor may contribute towards neuroprotection therapies. In this work, we performed hologram quantitative structure-activity relationship (HQSAR) on a series of thiophene trisubstituted derivatives. The best predictions were obtained for HQSAR model with $q^2=0.628$ and $r^2=0.986$. Statistical parameters from the generated QSAR models indicated the data is well fitted and have high predictive ability. HQSAR result showed that atom, bond and chirality descriptors play an important role in JNK3 activity and also shows that electronegative groups is highly favourble to enhance the biological activity. Our results could be useful to design novel and selective JNK3 inhibitors.

• 한국음향학회지
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• 제24권3호
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• pp.166-170
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• 2005

본 논문은 근접장 음향 홀로그래피를 이용한 수중 음원의 위치를 추정하는 기술에 대한 것이다. 수중 소음원의 식별에 적용 가능함을 실험으로 검증하고 그 결과를 기술하였다. 실험에 사용된 음원은 2개의 구형 센서로 구성되고 음원의 근거리 음압은 음원과 근접된 위치에 설정된 홀로그램 평면에서 측정된다. 측정된 음압에 대한 상호전력 스펙트럼으로부터 홀로그램 평면에서의 복소음압을 구하고 이를 공간 변환하여 음원 영역에서의 음장분포를 구하였다. 음원 영역에서의 음장분포 결과는 음원의 위치와 발생된 음원준위의 크기를 가시적으로 보여주며, 실험 결과는 음원의 위치와 음원준위의 상대적인 크기를 정확하게 추정하고 있어 근접장 음향 홀로그래피를 이용하여 수중 소음원의 위치 추정과 개별 소음원의 기여도 분석이 가능함을 확인하였다.

• 한국안전학회지
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• 제13권4호
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• pp.256-263
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• 1998

In this paper, we propose a volume holographic fingerprint recognition system based on optical correlator for personal identification. Optical correlator has high speed and parallel processing characteristics of optics. Matched filters are recorded into a volume hologram that can store data with high density, transfer them with high speed, and select a randomly chosen data element. The multiple reference images of database are prerecorded in a photorefractive crystal in the form of Fourier transform images, simply by passing the image displayed in a spatial light modulator through a Fourier transform lens. The angular multiplexing method for multiple holograms of database can be achieved by rotating the crystal by use of a step motor. Experimental results show that the proposed system can be used for the security verification system.

• 한국생산제조학회지
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• 제9권3호
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• pp.130-135
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• 2000

In this study the vibration behavior of the stiffened double cylinder was experimently analyzed. Due to the complex structure of the double cylinder the outside cylinder frequency responses to the exciting forces applied on various posi-tions were analyzed by using spectrum analyzer in conjunction with an accelerometer and the natural frequencies were obtained. The technique of time-averaged holographic interferometry is applied to study the vibration characteristics of outside cylinder with stiffening T frame. The experimental data showed that the T frame had salient effect of damping on the testing structure at most of resonances. however the experimental results also revealed interesting phenomenon. At some particular frequencies the T frame. The experimental data showed that the T frame had salient effect of damping on the testing structure at most of resonances. However the experimental results also revealed interesting phenomenon. At some particular frequencies the T frame seemed to behave as a transmitter. In addition it has been successfully demon-started that optical method such as holographic interferometry is well suited for the identification of mode shapes. They can give us a whole-field non-contact measurement instead of the point-wise measurement by accelerometer in classical modal testing.