• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.55.5-55
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• 2001

The MST (Minimum Spanning Tree) matching algorithm had been used for searching the part accord points extracted from the gray level fingerprint image. The method, however, had some limitations. To obtain the relationship between enrolled and inputted fingerprint, the MST was used to generate the tree graph that represent the unique graph for given fingerprint data. From the graph, the accord points are estimated. However, the shape of the graph highly depends on the positions of the minutiae. If there are some pseudo minutiae caused by noise, the shape of the graph will be different In this paper, to overcome the limitations of the MST, we proposed CRM (Center of Rotation Method) algorithm that found the true part accord points. The proposed method is based on the assumption ...

• 한국수산과학회지
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• 제48권2호
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• pp.221-232
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• 2015

Broadband echoes measured in live chub mackerel Scomber japonicus, goldeye rockfish Sebastes thompsoni, and fat greenling Hexagrammos otakii with different morphologies and internal characteristics were analyzed in time and frequency domains to understand the species-specific echo feature characteristics for classifying fish species. The mean echo image for each time-frequency representation dataset obtained as a function of orientation angle was extracted to mitigate the effect of fish orientation on acoustic scattering. The joint time-frequency content of the broadband echo signals was obtained using the smoothed pseudo-Wigner-Ville distribution (SPWVD). The SPWVDs were analyzed for each echo signature of the three fish species. The results show that the time-frequency analysis provided species-specific echo structure patterns and metrics of the broadband acoustic signals to facilitate fish species classification.

• 한국수산과학회지
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• 제50권2호
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• pp.195-206
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• 2017

Joint time-frequency images of the broadband echo signals of six fish species were obtained using the smoothed pseudo-Wigner-Ville distribution in controlled environments. Affine transformation and principal component analysis were used to obtain eigenimages that provided species-specific acoustic features for each of the six fish species. The echo images of an unknown fish species, acquired in real time and in a fully automated fashion, were identified by finding the smallest Euclidean or Mahalanobis distance between each combination of weight matrices of the test image of the fish species to be identified and of the eigenimage classes of each of six fish species in the training set. The experimental results showed that the Mahalanobis classifier performed better than the Euclidean classifier in identifying both single- and mixed-species groups of all species assessed.

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.8-12
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• 2016

In this paper, we theoretically and experimentally analyze the impact of speckle size of pseudo-thermal light source on ghost imaging. A larger size of speckle can bring improvements in SNR and visibility. At the same time, the edge blur of the retrieved image will become more serious. We also present a setup which can mitigate the edge blur of larger speckle while maintaining the advantages of higher SNR and visibility by changing the speckle size of the object beam with a concave lens.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.144-146
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• 2006

The Data Matrix of two-dimensional bar codes is a new technology capable of holding relatively large amounts of data compared to the conventional one-dimensional bar code which is just a key that can access detailed information to the host computer database. A secret key is used to prevent a watermark from malicious attacks. We encoded copyright information into a Data Matrix bar code for encoding process and it was spread a pseudo random pattern using owner key. We embedded a randomized watermark into the image using watermark's embedding position, pattern generated with a secret key. The experimental results have shown that the proposed scheme has good quality and is very robust to various attacks, such as JPEG compression and noise. Also the performance of the proposed scheme is verified by comparing the copyright information with the information which is extracted from a bar code scantier.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.606-608
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• 1998

Digital watermarking is the technique which embeds the invisible signal into multimedia data such as audio, video, images, for copyright protection, including owner identification and copy control information. In this paper, a new watermark detection algorithm by local masking cross covariance between watermarked signal and pseudo noise signal is proposed. The proposed algorithm enhances the detection probability for embedding information. Since reducing detection errors for the weak embedding signals, the algorithm improves the image quality and robusts against illegal attack to delete the embedding information and data compression applications such as JPEG and MPEGs.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.785-787
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• 2005

In the Bluetooth specification version 1.0, one specific frequency in one piconet was created depending upon the device clock and the Bluetooth native address at one specific time slot in the frequency hopping method. The basic hopping pattern was arranging the 79 ISM frequency band in pseudo-random fashion. Possible problem is the chance of collision of ownership of one specific frequency by more than 2 wireless devices when they are within the communication-active range. In this paper, we propose the adaptive frequency hopping method in order to resolve the possible problem so that more than 2 wireless devices communicates with their own client devices without being interfered. The proposed method was implemented with HDL later to be synthesized with an automatic EDA synthesizer and verified as well. The implemented adaptive frequency hopping circuit operated normally at 24MHz which will be the target clock frequency of the target Bluetooth device.

• 한국컴퓨터정보학회논문지
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• 제6권4호
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• pp.21-29
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• 2001

본 논문에서는 웨이브릿 변환 알고리듬을 이용하여 영상을 다해상도 변환하고, 중간주파대역의 중요한 계수에 각종 워터마크 시퀀스를 삽입 후 이의 강인성을 유사도 비교를 통하여 측정한다. 웨이브릿 변환은 주파수 영역 특성과 공간 영역의 특성을 함께 갖고 있는 장점을 가지고 있으며, 워터마크로는 임의 난수, 가우시안 시퀀스, 카오스 시퀀스 그리고 소벨 시퀀스를 이용한다. 다양한 공격에 대하여 실험한 결과 카오스 시퀀스가 다른 시퀀스들에 비해 높은 유사도를 보임으로써 향후 워터마크 시퀀스로 사용하기에 적합함을 보인다.

• International Journal of Internet, Broadcasting and Communication
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• 제16권1호
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• pp.124-131
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• 2024

Breast cancer classification using ultrasound, while widely employed, faces challenges due to its relatively low predictive value arising from significant overlap in characteristics between benign and malignant lesions, as well as operator-dependency. To alleviate these challenges and reduce dependency on radiologist interpretation, the implementation of automatic breast cancer classification in ultrasound image can be helpful. To deal with this problem, we propose a semi-supervised deep learning framework for breast cancer classification. In the proposed method, we could achieve reasonable performance utilizing less than 50% of the training data for supervised learning in comparison to when we utilized a 100% labeled dataset for training. Though it requires more modification, this methodology may be able to alleviate the time-consuming annotation burden on radiologists by reducing the number of annotation, contributing to a more efficient and effective breast cancer detection process in ultrasound images.

• 보존과학회지
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• 제16권
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• pp.64-76
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• 2004

지사동 출토 슬래그에 대하여 화학적인 분석과 현미경 조직관찰에 의하여 금속학적인 조사연구를 수행하였다. 화학적인 분석은 ICP, XRD, SEM-EDS로 실행하였으며 슬래그 조직은 금속현미경 및 SEM으로 관찰하였다. 화학적 분석 결과, A 및 C 지구 슬래그의 전철량(Total Fe)은 $39\~45\%$ 로 고대 제철과정에서 발생했던 철분의 평균치에 해당하였다. 또한 CaO 성분은 $3\~8\%$로 많은 양은 아니지만 조재제로 Ca성분을 함유한 재료를 소량 사용한 것으로 사료되었다. A지구에서는 Ti성분이 미량 검출되었으며 C지구에선 Ti 성분과 V 성분이 다량 검출되었다. XRD 분석 결과 Fayalite, Wustite, Magnetite, Ilmenite, Pseudo - brookite, Ulvospinel, Forsterite, Fephroite, Olivine 같은 화합물이 검출되었다. 이는 금속현미경 및 SEM에 의한 관찰에서도 위와 같은 조직을 확인하였다. 따라서 A지구의 로에서는 주로 철광석을 이용한 제련작업을 하였고 C지구의 제철로에서는 철광석을 원료로 하는 제련작업과 사철을 원료로 하는 제련작업이 병행되었던 것으로 추정되었다.