• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2677-2684
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• 2009

In this paper, we study a watermarking method based on the informed coding and embedding by means of trellis code and entropy masking. An image is divided as $8{\times}8$ block with no overlapping and the discrete cosine transform(DCT) is applied to each block. Then the 16 medium-frequency AC terms of each block are extracted. Next it is compared with gaussian random vectors having zero mean and unit variance. As these processing, the embedding vectors with minimum value of linear combination between linear correlation and Watson distance can be obtained by Viterbi algorithm at each stage of trellis coding. For considering the image characteristics, we apply different weight value between the linear correlation and the Watson distance using the entropy masking. To evaluate the performance of proposed method, the average bit error rate of watermark message is calculated from different several images. By the experiments the proposed method is improved in terms of the average bit error rate.

• Annual Conference on Human and Language Technology
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• 2019.10a
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• pp.475-477
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• 2019

문장 부호란, 글에서 문장의 구조를 잘 드러내거나 글쓴이의 의도를 쉽게 전달하기 위하여 사용되는 부호들로, 따옴표나 쉼표, 마침표 등이 있다. 대화 시스템과 같이 컴퓨터가 생성해 낸 문장을 인간이 이해해야 하는 경우나 음성 인식(Speech-To-Text) 결과물의 품질을 향상시키기 위해서는, 문장 부호의 올바른 삽입이 필요하다. 본 논문에서는 이를 수행하는 딥 러닝 기반 모델을 훈련할 때 필요로 하는 한국어 말뭉치를 구축한 내용을 소개한다. 이 말뭉치는 대한민국정부에서 장관급 이상이 발언한 각종 연설문에서 적절한 기준을 통해 선별된 고품질의 문장으로 구성되어 있다. 문장의 총 개수는 126,795개이고 1,633,817개의 단어들(조사는 합쳐서 한 단어로 계산한다)로 구성되어 있다. 마침표와 쉼표는 각각 121,256개, 67,097개씩이다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.896-900
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• 2002

본 논문에서는 기존의 워터마킹 알고리즘보다 채널에 대해서 더욱 강인한 특성을 위해 오류 정정 능력이 뛰어난 터보 부호 및 인간 시각 시스템을 이용한 디지털 워터마킹 방법을 제안하였다. 이 알고리즘에서는 터보 부호를 이용하여 워터마크를 생성하고, 채널에 강인한 특성을 위해 채널의 부가 정보를 이용하여 워터마크를 삽입한다. 제안한 워터마킹 알고리즘의 성능 평가를 위한 모의실험에서 제안한 워터마킹 알고리즘이 기존의 알고리즘보다 견고성면에서 우수함을 확인하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.91-101
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• 2012

DNA watermarking have been interested for both the security of private genetic information or huge DNA storage information and the copyright protection of GMO. Multimedia watermarking has been mainly designed on the basis of frequency domain, such as DCT, DWT, FMT, and so on, for the robustness and invisibility. But a frequency domain watermarking for coding DNA sequence has a considerable constraint for embedding the watermark because transform and inverse transform must be performed without completely changing the amino acid sequence. This paper presents a coding sequence watermarking on lifting based DWT domain and brings up the availability of frequency domain watermarking for DNA sequence. From experimental results, we verified that the proposed scheme has the robustness to until a combination of 10% point mutations, 5% insertion and deletion mutations and also the amino preservation and the security.

• Journal of Korea Multimedia Society
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• v.10 no.11
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• pp.1427-1438
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• 2007

Video watermarking technologies are classified into types of four kinds. The first type is to embed the watermark into a raw video signal and to code the watermarked video signal. Most of video watermarking technologies fall into the category of this type. The second type is to apply watermarking to the coding process, such as block DCT and quantization. The third is to directly embed the watermark into the compressed bitstream itself. Generally, it is referred as labelling rather than watermarking. Finally, the fourth is to embed the water mark into MPEG motion vector. This type has the difficulty in real-time process because of the high complexity and has the blocking effects because of DCT-based on coder. In this paper, we proposed the digital video watermarking that embed the watermark in SPIHT video code for I-frame using motion vector analysis. This method can remove the blocking effect occurred at the DCT-based on coder and obtain video data that has progressive transmission property. The proposed method is to select the region for the watermark embedding in I frame using motion vector estimated from the previous P or B frame. And then, it is to perform DWT and embed the watermark based on HVS into the wavelet coefficients in the same subband of DWT as the motion vector direction. Finally, the watermarked video bitstream is obtained by the SPIHT coder. The experimental results verified that the proposed method has the invisibility from the objective and subjective image quality and the robustness against the various SPIHT compression and MPEG re-code.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.2
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• pp.123-133
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• 2012

This paper discuss about DNA watermarking using coding DNA sequence (CDS) for the authentication, the privacy protection, or the prevention of illegal copy and mutation of DNA sequence and propose a DNA watermarking scheme with the mutation robustness and the animo acid preservation. The proposed scheme selects a number of codons at the regular singularity in coding regions for the embedding target and embeds the watermark for watermarked codons and original codons to be transcribed to the same amino acids. DNA base sequence is the string of 4 characters, {A,G,C,T} ({A,G,C,U} in RNA). We design the codon coding table suitable to watermarking signal processing and transform the codon sequence to integer numerical sequence by this table and re-transform this sequence to floating numerical sequence of circular angle. A codon consists of a consecutive of three bases and 64 codons are transcribed to one from 20 amino acids. We substitute the angle of selected codon to one among the angle range with the same animo acid, which is determined by the watermark bit and the angle difference of adjacent codons. From in silico experiment by using HEXA and ANG sequences, we verified that the proposed scheme is more robust to silent and missense mutations than the conventional scheme and preserve the amino acids of the watermarked codons.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.421-423
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• 2001

H.263 부호화 기법에 비해 H.263+에서의 주용 특징중 하나는 에러 강인성으로, 그중에서 계층부호화 모드는 한 개의 송신 영상에 대해서도 복호기와 전송로에 따라 여러 가지 화질의 재생 영상을 얻을 수 있는 기능, 즉 에러 및 패킷 손실 발생 가능 채널에서 비디오 정보 전송시 디코더측에서 사용 가능한 다양한 비트율, 해상도, 디스플레이 율을 허용함으로써 비디오 정보에 대한 전송을 향상시키는 기법이다. FEC(Forward Error Correction)기법에 의한 부가적인 비트 삽입에 제한적인 저 대역폭 네트워크 및 무선 통신망과 같은 네트워크 환경에서는 ATM(Asynchronous Transfer Mode)망에서와 같인 계층부호화된 비트 스트림의 기본 계층에 대해 무손실 전송이 어려우므로, 고급계층과 동등한 채널을 통해 전송시 기본계층 및 고급계층 모두에 대해서는 에러가 발생 할 수 있다. 따라서, 본 연구에서는 저대역폭 비디오 전송을 위해 계층 부호화 모드중 SNR(Signal to Noise Ratio) 계층부호화로 부호화된 비트스트림을 에러 발생가능 채널로 전송시 각 계층에 대한 에러의 영향력을 실험한다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.11-18
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• 1998

A binary line code, called MB46d, is designed by use of the BUDA(Binary Unit DSV and ASV) cell concept to retain the property of being runlength limited, DC tree, and with a power spectral null at the Nyquist frequency. This new code is a stateless line code with a simple encoding and a decoding rule and enables efficient error monitoring. The power spectrum and the eye pattern of the new line code are simulated for a minimum-bandwidth digital transmission system where the sinc function is used as a basic pulse. The obtained power null at the Nyquist frequency is wide enough to enable easy band-limiting as well as secure insertion of a clock pilot where necessary. The eye is also substantially wide to tolerate a fair amount of timing jitter in the receiver.

• Journal of Satellite, Information and Communications
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• v.4 no.1
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• pp.14-20
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• 2009

This paper describes synchronization concept and algorithm of the reverse DS-SS/TDMA control channel to handle satellite terminals which are distributed through the mission area. Military satellite control channel should have ECCM capabilities and handle more than several hundreds satcom terminals simultaneously. DS-SS/TDMA control channel can satisfy these demand but it spend much synchronization time. Proposed algorithm insert the preamble which is divided with several short sub bins prior to control data and use the parallel matched filtering searcher for each sub bin. As a result of the test, proposed algorithm can acquire most of control channel packet successfully within several milliseconds in severe jamming environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.262-271
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• 2004

There are channel errors when video data are transmitted between encoder and decoder. These channel errors would make decoded image incorrect, so it is very important to detect and recover channel errors. This paper proposes a method of error detection and recovery by hiding specific information into video bitstream using fragile watermark and checking it later. The proposed method requires no additional bits into compressed bitstream since it embeds a user-specific data pattern in the least significant bits of LEVELs in VLC codewords. The decoder can extract the information to check whether the received bitstream has an error or not. We also propose to use this method to embed essential data such as motion vectors that can be used for error recovery. The proposed method can detect corrupted MBs that usually escape the conventional syntax-based error detection scheme. This proposed method is quite simple and of low complexity. So the method can be applied to multimedia communication system in low bitrate wireless channel.