• Journal of Broadcast Engineering
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• v.22 no.3
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• pp.295-312
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• 2017

Digital video content is the most information-intensive and high-value content. Therefore, it is necessary to protect the intellectual property rights of these contents, and this paper also proposes a watermarking method of digital image for this purpose. The proposed method uses the frequency characteristics of 2-Dimensional Discrete Wavelet Transform (2D-DWT) for digital images and digital watermark on global data without using local or specific data of the image for watermark embedding. The method to insert digital watermark data uses a simple Quantization Index Modulation (QIM) and a multiple watermarking method that inserts the same watermark data in multiple. When extracting a watermark, multiple watermarks are extracted and the final watermark data is determined by a simple statistical method. This method is an empirical method for experimentally determining the parameters in the watermark embedding process. The proposed method performs experiments on various images against various attacks and shows the superiority of the proposed method by comparing the performance with the representative existing methods.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1155-1160
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• 2011

The importance of broadband wireless communication implemented at subway tunnels is growing up. At 18GHz wireless video transmission system, the transmitter requires a digital modulation method. At subway tunnel, A 18GHz's influence of the multi-pass padding is strong. OFDM digital modulation that is strong for multi-pass padding is recommended. Duplexing methode uses FDD to transmit and receive broadband data at the same time. In the case of FDD we assign a private use channel each with the transmission at the receiving. In this paper, We implement multiple access wireless OFDM transceiver. We verified that one ground transceiver communicates with two car transceiver at the same time.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1008-1013
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• 2011

The importance of broadband wireless communication system at subway tunnels is growing up. At 18GHz wireless video transmission system, the transmitter requires a digital modulation method. At subway tunnel, A 18GHz's influence of the multi-pass padding is strong. OFDM digital modulation that is strong for multi-pass padding is recommended. Duplexing methode uses FDD to transmit and receive broadband data at the same time. In the case of FDD we assign a private use channel each with the transmission at the receiving. In this paper, We implement multiple access wireless OFDM transceiver. We verified that one ground transceiver communicates with two car transceiver at the same time.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.565-568
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• 2005

Even though there has been a great deal of research and development for the compression techniques such as H.263, MPEG-1, and MPEG-2 in DVR systems, an efficient scheme for storing, accessing, and managing the huge amount of video data from multi-channel cameras needs to be developed. In this paper, we describe an implementation of MPEG-4 encoder for PC-based real-time multi-channel DVR systems.

• Journal of Korea Multimedia Society
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• v.2 no.4
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• pp.438-450
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• 1999

In this paper, a new watermaking method embedding digital watermarks in the compressed video for the copy protection of multimedia data. The proposed method segments objects and embeds independent watermarks in each objects by spread spectrum method in the bitstream domain which is compressed by DCT and motion compensated coding method like MPEG-2. And, the proposed method not only embeds watermarks but show the robustness to the attacks like average operation or statistical analysis.

• Journal of Digital Contents Society
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• v.9 no.4
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• pp.679-686
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• 2008

Wireless LAN(WLAN) is a rather mature communication technology connecting mobile terminals. IEEE 802.11 is a representative protocol among WLAN technologies. With the rising popularity of delay-sensitive real-time multimedia applications(video, voice and data) in IEEE 802.11 wireless LAN, it is important to study the MAC layer delay performance of WLANs. In this paper, performance for packet delay model that recently have been proposed schemes is analysed in wireless LAN and proved performance results via simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.196-201
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• 2010

영상보안 시장은 DVR(Digital Video Recorder)을 중심으로 아날로그 시스템을 디지털로 빠르게 대체하며 네트워크를 이용한 고화질 시장으로 발전을 거듭하고 있다. DVR의 핵심적인 기능인 녹화, 검색 기능은 시스템에서 상대적으로 속도가 느린 디스크 자원의 의존도가 높은 기능으로 성능에 직접적인 영향을 미치는 녹화 파일 포맷이 최적화 되지 않을 경우 심각한 성능 문제를 일으킬 수 있다. 본 논문에서는 인덱스를 이용하여 고속 탐색 및 재생 성능을 유지하면서 비디오와 오디오 데이터 외에도 다양한 형태의 이벤트 데이터를 수용하여 DVR의 녹화와 검색 기능의 실제 운용 환경에 적합한 AMS (Advanced Multi-channel Streaming) 파일 포맷을 설계하고 최근 DVR 전용 파일 포맷으로 제안된 ESP 파일 포맷과의 비교 실험을 통하여 기능 및 성능이 향상되었음을 확인 하였다.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2427-2429
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• 1998

Digital watermarking is the techinque which embeds the invisible signal into multimedia data such as audio, video, images, for copyright protection, including owner identification and copy control information. This paper proposes a new watermark embedding and extraction technique by extending the direct sequence spread spectrum technique. The proposed technique approximates the frequency component of pixels in spatial domain by using Laplacian mask and adaptively embeds the watermark considering the HVS to reduce the degradation of Image. In watermark extraction process, the proposed technique strengthens the high frequency components of image and extracts the watermark by demodulation. All this processes are performed in spatial domain to reduce the processing time.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.11a
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• pp.183-186
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• 2003

DMB(Digital Multimedia Broadcasting)는 유럽의 디지털 오디오 방송규격인 Eureka-147 DAB(Digital Audio Broadcasting) 전송시스템을 기반으로 하여 동영상 및 음성, 문자데이터 등을 포함한 멀티미디어 서비스를 제공하기 위한 새로운 방송표준이다 따라서 DMB 시스템은 Eureka-147 DAB 전송부 이외에 영상 및 음성을 압축하는 미디어압축 (복)부호화부, 압축된 미디어 스트림을 다중화 하는 비디오 (역)다중화부가 추가된 구조를 갖는다. 본 논문은 DMB 표준의 비디오 다중화부의 분석을 통하여 확장된 전송기능 및 높은 전송효율을 제공할 수 있는 새로운 비디오 다중화 구조를 제시한다. 또한 표준 비디오 다중화기와 제안된 비디오 다중화기의 성능평가를 위해 기능적으로 분석하고 시뮬레이션을 통해 전송효율을 측정하였다.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.650-654
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• 1995

In digital video recording, higher areal density is strongly required for realizing digital VCRs. In order to accomplish higher areal density. we have implemented a system that has a narrow track pitch and can record data of about 30 Mbps(15 Mbps per channel) with the conventional S-VHS tapes. After computer simulation using the characteristics of the experimental system, we have selected appropriate equalizer and detection method by taking into account performance and cost (including hardware complexity). As a result, the selected equalizer and detection schemes are cosine equalizer and integrated de tection, respectively. The implemented system confirms reliable operation with a symbol error rate of less than $1{\times}10^{-4}$. In this paper, We will show the performance of the implemented system together with simulation results.