• Journal of Broadcast Engineering
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• v.11 no.3 s.32
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• pp.363-378
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• 2006

The Digital Multimedia Broadcasting(DMB) system is developed to offer high quality audio-visual multimedia contents to the mobile environment. The system adopts MPEG-4 standard for the main video, audio and other media format. It also adopts the MPEG-4 scene description for interactive multimedia contents. The animated and interactive contents can be actualized by BIFS(Binary Format for Scene), the binary format for scene description that refers to the spatio-temporal specifications and behaviors of the individual objects. As more interactive contents are, the scene description is also needed more high bitrate. However, the bandwidth for allocating meta data such as scene description is restrictive in mobile environment. On one hand, the DMB terminal starts demultiplexing content and decodes individual media by its own decoder. After decoding each media, rendering module presents each media stream according to the scene description. Thus the BIFS stream corresponding to the scene description should be decoded and parsed in advance of presenting media data. With these reason, the transmission delay of BIFS stream causes the delay of whole audio-visual scene presentation although the audio or video streams are encoded in very low bitrate. This paper presents the effective optimization technique for adapting BIFS stream into expected MPEG-2 TS bitrate without any bandwidth waste and avoiding the transmission delay of the initial scene description for interactive DMB contents.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.311-318
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• 2001

In recent years, users\` demands for multimedia service are increasing because of a diffusion of internet. Server systems, however, offer inefficient multimedia data service to users. Multimedia applications often transfer the same data between shared devices at very high rates, and therefore require an efficient I/O subsystem. Data copying and context switching have long been identified as sources of I/O inefficiency. Therefore we propose the new Multimedia Stream System Call (MSSC) mechanism, which is inserted into a Linux kernel: The MSSC mechanism operates in kernel domain with RTP (Real-time Transport Protocol). We present measurements indicating that use of our techniques resulted in a 12.5%∼14% gain in throughput as compared with a conventional Linux system.

• Journal of Korea Multimedia Society
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• v.20 no.6
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• pp.853-864
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• 2017

HD padding area is essential redundancy in HD broadcasting. It is possible to use this padding area for the purpose of improving DTV broadcasting services. For utilization of this area, The bit of a service data was converted to black and white $8{\times}8$ block image. Converted block images are compressed with active video and are delivered to a receiver as only DC coefficients in a video stream. video quality is not effected by the proposed method, and service data was perfectly recovered in receiver without errors by using block average and threshold. The proposed utilization of HD essential padding area can possibly overcome the limited transmission stream rate with the bandwidth of HD broadcasting. If service data in transport or video stram were transferred using this padding area, it is possible to improve video quality with expanded video stream rate. Additionally, because the proposed methods are based on well-established standards, it is also useful for world-wide HD broadcasting systems such as ATSC, DVB, and IPTV.

• ETRI Journal
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• v.31 no.6
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• pp.795-802
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• 2009

This paper presents the design of an advanced terrestrial digital multimedia broadcasting (AT-DMB) baseband receiver SoC. The AT-DMB baseband is incorporated into a hierarchical modulation scheme consisting of high priority (HP) and low priority (LP) stream decoders. The advantages of the hierarchical modulation scheme are backward compatibility and an enhanced data rate. The structure of the HP stream is the same as that of the conventional T-DMB system; therefore, a conventional T-DMB service is possible by decoding multimedia data in an HP stream. An enhanced data rate can be achieved by using both HP and LP streams. In this paper, we also discuss a time deinterleaver that can deinterleave data for a time duration of 384 ms or 768 ms. The interleaving time duration is chosen using the LP symbol mapping scheme. Furthermore, instead of a Viterbi decoder, a turbo decoder is adopted as an inner error correction system to mitigate the performance degradation due to a smaller symbol distance in a hierarchically modulated LP symbol. The AT-DMB baseband receiver SoC is fabricated using 0.13 ${\mu}m$ technology and shows successful operation with a 50 mW power dissipation.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.775-779
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• 2011

As the technology of multimedia sensor networks is desired in large numbers of applications nowadays, real-time service becomes one of the most important research challenges. Even though lots of related works have been conducted to meet this requirement in several ways, the specific traffic model for real-time has not been taken yet. Thus, it causes lack of adaptability of those approaches in real deployment. To solve this problem, in this paper, we model the application via (m,k)-firm streams which have weakly hard real-time property. And then, a novel forwarding scheme based on modified DBP (Distance-Based Priority) is proposed by considering local-DBP and stream DBP together. Local-DBP can contribute to identify the detailed causes of unsatisfied quality, that is, network congestion or wireless link failure. Simulation results reveal that (m,k)-firm is a good traffic model for multimedia sensor networks and the proposed scheme can contribute to guarantee real-time requirement well.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.275-278
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• 2003

Terrestrial DMB(Digital Multimedia Broadcasting) system is the standard that offers multimedia broadcasting services at mobile environment and is based on Eureka-147 DAB(Digital Audio Broadcasting) for transmission method. Also DMB provides the error protection method of convolution coding. In this paper, we study on the effective error resilience coding of MPEG-4 video stream over DMB system. To accomplish error resilience, we first partition one data into several data using the data partitioning, and we control the coding rate of the convolution coding according to the importance of the partitioned data. In this algorithm, we suggest and analyze the efficient rate control algorithm considering convolution code rate.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.279-282
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• 2003

Terrestrial DMB(Digital Multimedia Broadcasting) system is the standard that offers multimedia broadcasting services at mobile environment and is based on Eureka-147 DAB(Digital Audio Broadcasting) for transmission method. Also DMB provides the error protection method of convolution coding. In this paper, we study on the effective error resilience coding of MPEG-4 video stream over DMB system. To accomplish error resilience, we first partition one data into several data using the data partitioning, and we control the coding rate of the convolution coding according to the importance of the partitioned data. In this algorithm, we suggest and analyze the efficient rate control algorithm considering convolution code rate.

• ETRI Journal
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• v.31 no.1
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• pp.65-67
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• 2009

We introduce an advanced terrestrial digital multimedia broadcasting (AT-DMB) system that overcomes the limitation of data transmission rates of T-DMB by doubling it with the same frequency bandwidth. In this letter, we propose an efficient algorithm which generates a scalable transport stream in AT-DMB by multiplexing certain types of elementary streams encoded using scalable video coding and an MPEG-surround audio coder for high-quality multimedia services.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2060-2063
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• 2003

Terrestrial DMB(Digital Multimedia Broad-casting) system that is now under standardization in Korea offers multimedia broadcasting services at mobile environment and is based on Eureka-147 DAB(Digital Audio Broadcasting) for transmission method. Also DMB provides the error protection method of convolution coding. In this paper, we study on the effective error resilience coding of MPEG-4 video stream over DMB system. In our algorithm, the first, we partition the MPEG-4 data using the MPEG-4 data partitioning method, and then controls the convolution coding rate according to the importance of the partitioned data. From our simulation result, we show that our algorithm is proper for terrestrial DMB services.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11a
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• pp.167-170
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• 2002

본 고의 Multi-Media Caching System 은 이동 단말기의 보급 & 발달로 예상되는 Trans-coder 부하의 증가와 응답 시간 개선 하기 위한 것으로 기존의 Web 문서의 Caching System 과 비교 분석 하고, 빈번한 이동 단말기의 요구에 의해서 발생하는 않은 trans-coder 작업을 최소화 할 수 있는 XML 기반의 Caching System을 연구 하고자 한다. 즉, 기존의 Web Caching System의 장점과 XML의 재 사용 성, 확장 성, 플랫폼 독립성, 다양한 종류의 응용 프로그램과의 접목성 등의 장점을 살리고, Cache System Manager에 의해 최소환의 Trans-coder 동작이 일어나도록 한다. 따라서 Trans-coder 된 작업을 Caching System 에 보관 관리 하는 최적의 Caching System Manager 방법을 제안하고자 한다.