• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.3
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• pp.3-13
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• 2002

There are cases that revoke the certification because of disclosure of private key, deprivation of qualification and the expiration of a term of validity on PKI. So, a user has to confirm the public key whether valid or invalid in the certification. There are many methods such as CRL, Delta-CRL, OCSP for the cert-validation of certification. But these methods have many problems, which cause overload traffic on network and the CRL server because of realtime processing for cert-validation of certification. In this paper we proposed cert-validation of certification improvement method based on FM Subcarrier Broadcasting, which solved problems that are data integrity by different time between transmission and receiving for CRL, and overload traffic on network and the CRL server the realtime management.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10a
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• pp.676-678
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• 2001

공개키 기반 인증시스템에서 사용자의 실수로 비밀키가 노출되었거나 자격의 박탈, 유효기간 만료 등의 이유로 인증서를 폐지해야 할 경우가 있다. 이에 따라서 각 사용자는 수신한 인증서가 유효한 것인지를 확인해야만 한다. 이 인증서 폐지 여부를 확인하는 방법으로는 CRL, Delta-CRL OCSP 등의 방식이 개발되었다. 하지만 이 모든 방식에서의 인증서 유효성 검증은 실시간으로 처리해야 하므로 많은 통신량을 발생시키는 문제점을 가지고 있다. 본 논문에서는 CRL관리의 문제점인 전송시점 차이에 따른 무결성 문제와 실시간 처리를 인한 서버와 네트워크 과도한 트래픽 발생을 해결한 FM Subcarrier Broadcasting을 이용한 효율적인 CRL 구축방안을 제안하였다.

• The Journal of the Acoustical Society of Korea
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• v.10 no.2
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• pp.44-51
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• 1991

In this paper, we have studied the FM-extended broadcasting which makes the enhancement of stereo signal-to-noise ration by utilizing the compression technique and quadrature moduation method of standard subcarrier signal in transmitter station, and corresponding demodulation method and expansion technique in receiver system. The proposed system is completely compatible with the conventional FM stereo system. We have confirmed the validity of the proposed method by implementation of transmitter/receiver system including quadrature modulation/demodulation and companding system.

• Journal of the Korea Computer Industry Society
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• v.2 no.6
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• pp.791-802
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• 2001

In this paper, DARC(Data Radio Channel) error correction decoder for the U Subcarrier Broadcasting System is designed of using (272,190)$\times$(272,190) product code based on (272,190) shortened difference set cyclic code. This decoder has error flag of column and row direction that can store the result of the error correction of column and row direction in the block and frame structure, is designed to be of no benefit the output with majority logic determination to cancel the corrected and determined bit, and can improve by using the error correction method that no error correction of the row direction is performed, if error correction of the column direction is completely performed by error flag.