• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.223-228
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• 2007

근래 주목받는 키워드인 유비쿼터스(Ubiquitous), UCC(User Created Contents) 등은 기술적 발달과 함께한 사람들의 행동 양식 변화를 잘 반영하고 있다. 기술적인 측면에서 모바일 환경으로의 진화는 사람들에게 시공간적 제약을 없애주었으며, '호모 루덴스'로 표현된 유희적 인간의 개념은 현대인의 행동 양식을 잘 표현했다. 이중 지상파 이동 멀티미디어 방송(Digital Multimedia Broadcasting, DMB)은 방송에 있어서 시공간적 제약을 없앤 대표적인 사례이며, 'EDUTAINMENT(에듀테인먼트)'는 교육에 유희를 결합한 실례라고 하겠다. 특히 DMB는 정보와 유희의 욕구를 기본적으로 충족시킬 수 있는 방송이라는 매체를 이용한다는 점에서 에듀테인먼트의 기술적 기반이 될 수 있으며, 이를 통해 저 연령의 학습자에게 유희와 교육을 동시에 제공함으로써, 학습효과를 높일 수 있는 장점이 있다. 본 논문에서는 DMB 시스템을 위한 유아 대상의 에듀테인먼트 어플리케이션을 설계하고, 구현한다. 이 어플리케이션을 위해 스토리텔링, 음악과 악기 선택 시스템, 타임라인 및 자유표면 게임 시스템 등 DMB 시스템에 적절하며, 에듀테인먼트의 조건을 충족하는 몇 가지 방법론을 제안하여 방송을 통해 콘텐츠와 대상자가 서로 상호작용 할 수 있도록 한다. 이를 위해서는 기존 방송의 음성, 영상 서비스를 넘어 상호작용의 필수적인 요소라고 할 수 있는 데이터 서비스를 요구하며, 이는 MPEG-4 Part 11: BIFS(Binary Format for Scenes) 기술을 기반으로 그 구현에는 VRML에 기초한 BT(BIFS Text) 언어를 사용한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.251-253
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• 2008

최근 유럽에서 DVB-T HDTV 방송 표준이 정하지면서 오디오 포맷으로 HE-AAC가 채택되었다. HE-AAC는 압축효율은 높지만 연산량이 높아 낮은 성능의 DSP에서 수행하기에는 어려움이 있다. DVB-T에서는 5.1채널을 사용하고 있어 더욱더 많은 연산을 필요로 한다. 본 논문은 ISO/DEC 14496-3 MPEG4 HE(High Efficiency)-AAC의 Level4에 해당하는 Multichannel Decoder를 최적화하여 구현하고. 가장 많은 연산을 필요로 하는 Synthesis Filter Bank에 제안된 알고리즘을 적용하여 연산량을 줄였고 대부분의 연산부를 어셈블리로 코드 최적화를 하여 작은 성능의 DSP를 사용하여 실시간 Multichannel HE-AAC Audio Decoder의 구현이 가능하게 하였다. DVB-T 오디오 시스템에 필수로 필요한 Audio Description, Dynamic Range Control, Downmix 등을 함께 구현하여 실제 수신기에 사용이 가능하도록 하였다. DSP는 Samsung의 CalmRISC16 + MAC24 core 를 사용하였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.1
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• pp.34-39
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• 2004

Huffman coding which has been used in many data compression algorithms is a popular data compression technique used to reduce statistical redundancy of a signal. It has been proposed that the Huffman algorithm can decode efficiently using characteristics of the Huffman tables and patterns of the Huffman codeword. We propose a new Huffman decoding algorithm which used a multi way tree search and present an efficient hardware implementation method. This algorithm has a small logic area and memory space and is optimized for high speed decoding. The proposed Huffman decoding algorithm can be applied for many multimedia systems such as MPEG audio decoder.

• Information and Communications Magazine
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• v.14 no.8
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• pp.104-117
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• 1997

본 고에서는 ATM(Asynchronous Transfer Mod) 교환기에 4선식의 HDSL 정합기능을 구현하고, 기존의 음성전화 가입자 서비스 매체로서 완전 동 선로를 이용하여 HDSL(High-rate Digital Subscriber Line) 서비스를 제공하기 위한 가입자 서비스 루프 거리 및 셀 손실 성능을 평가하였다. 이 평가는 전이중 2B1Q 전송 방식을 지원하는 HDSL 정합장치를 통하여 누화, 임펄스 등 구리전화선(copper telephone line)에 존재하는 중요한 전송 손실을 감안한 CSA(Carrier Serving Area)환경에서 각각 26게이지 <0.4 mm> 선로와 24 게이지(0.5 mm) 페어 선로를 이용하여 E1 급(2.048 Mbps)데이터 전송할 때 $10^7$의 셀 손실 율을 만족하는 가입자 서비스 루프 거리를 평가하였다. 또한, ATM 시스템 하의 시범환경에서 MPEG-1급 주문형 비디오서비스, 영상회의 서비스 및 고속 인터넷 접속 서비스 등의 대표적인 서비스 데모를 실시하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1117-1123
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• 2008

Applications for mobile multimedia are testing the performance limits of present day CPUs with variety. However, hardwired solutions are inflexible and expensive to develop. CPUs with flexibility have limitation of performance. So, the requirement for both ASIC-like performance and CPU-like flexibility has led to reconfigurable processor. Mobile systems require low power and high performance concurrently. In this paper, we propose reconfigurable processor for mobile multimedia with high energy efficiency. Reconfigurable processor with 121MOPS/mW is developed by 130nm CMOS technology. And the processor was simulated for energy efficiency with 539MOPS/mW by 90nm CMOS technology and effective use of instructions. And we tested its applications for multimedia field. We tested the case of inverse MDCT for MP3 and DF for MPEG4 and ME for H.264.

• Journal of Broadcast Engineering
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• v.15 no.3
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• pp.346-354
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• 2010

T-DMB is using MPEG-4 BIFS standard format for broadcasting interactive data service. BIFS enables us to represent contents as a scene which consists of various objects such as AV, image, graphic, and text. It also enables us to control objects by using user interaction. BIFS was designed to be adapted to multimedia systems with various input devices. Today, however, we are in lack of considering about mobile device with restricted input unit. The problem is that a consistent user control of interactive data contents is not possible due to the limitations of input units in T-DMB terminals. To solve the problem, we defined KeyNavigator node that provides a means to select or navigate objects (like menu) in BIFS contents by arrow keys and enter key of mobile terminal. By using KeyNavigater node, not only BIFS contents providers can make BIFS contents as they want, but also users can get a way to control BIFS contents consistently and easily.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3C
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• pp.297-303
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• 2009

Integral imaging is a well-known 3D image recording and display technique. The huge size of integral imaging data requires a compression scheme to store and transmit 3D scenes. In the conventional compression scheme, the data amount of elemental images depends on the various recording condition such as the positional location of a 3D object, the illumination and specification of the lenslet array even if an identical pickup system is used. In this paper, to reduce the dependence of the image characteristics of elemental images on the pickup conditions, a compression scheme using block division on the elemental image of integral imaging is proposed. The proposed scheme provides an improved compression ratio by considering the local similarity of elemental images picked up from three-dimensional objects according to a positional location. To test the proposed scheme, various elemental images are picked up and a compression process is then carried out u sing a standard MPEG-4. Based on compression ratio results, the proposed compression scheme is improved by approximately 9% compared with the conventional compression method.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.269-275
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• 2014

The DAB system was designed to provide CD quality audio and data services for fixed, portable and mobile applications with the required BER below $10^{-4}$. However for the T-DMB system with the video service of MPEG-4 stream, BER should go down $10^{-8}$ by adding FEC blocks which consist of the Reed-Solomon (RS) encoder/decoder and convolutional interleaver/deinterleaver. In this paper we propose two types of turbo coded T-DMB system without altering the puncturing procedure and puncturing vectors defined in the standard T-DMB system for compatibility. One(Type 1) can replace the existing RS code, convolutional interleaver and RCPC code by a turbo code and the other one (Type 2) can substitute the existing RCPC code by a turbo code. Simulation results show that two new turbo coded systems are able to yield considerable performance gain after just 2 iterations. Type 2 system is better than type 1 but the amount of performance improvement is small.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.5 s.305
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• pp.29-40
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• 2005

According as base of digital hologram has been magnified, discussion of compression technology is expected as a international standard which defines the compression technique of 3D image and video has been progressed in form of 3DAV which is a part of MPEG. As we can identify in case of 3DAV, the coding technique has high possibility to be formed into the hybrid type which is a merged, refined, or mixid with the various previous technique. Therefore, we wish to present the relationship between various image/video coding techniques and digital hologram In this paper, we propose an efficient coding method of digital hologram using standard compression tools for video and image. At first, we convert fringe patterns into video data using a principle of CGH(Computer Generated Hologram), and then encode it. In this research, we propose a compression algorithm is made up of various method such as pre-processing for transform, local segmentation with global information of object image, frequency transform for coding, scanning to make fringe to video stream, classification of coefficients, and hybrid video coding. Finally the proposed hybrid compression algorithm is all of these methods. The tool for still image coding is JPEG2000, and the toots for video coding include various international compression algorithm such as MPEG-2, MPEG-4, and H.264 and various lossless compression algorithm. The proposed algorithm illustrated that it have better properties for reconstruction than the previous researches on far greater compression rate above from four times to eight times as much. Therefore we expect that the proposed technique for digital hologram coding is to be a good preceding research.

• The Journal of the Acoustical Society of Korea
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• v.14 no.2E
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• pp.91-97
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• 1995

This paper describes the implementation of a multi-channel audio codec for HETV. This codec has the features of the 3/2-stereo plus low frequency enhancement, downward compatibility with the smaller number of channels, backward compatibility with the existing 2/0-stereo system(MPEG-1 audio), and multilingual capability. The encoder of this codec consists of 6-channel analog audio input part with the sampling rate of 48 kHz, 4-channel digital audio input part and three TMS320C40 /DSPs. The encoder implements multi-channel audio compression using a human perceptual psychoacoustic model, and has the bit rate reduction to 384 kbit/s without impairment of subjective quality. The decoder consists of 6-channel analog audio output part, 4-channel digital audio output part, and two TMS320C40 DSPs for a decoding procedure. The decoder analyzes the bit stream received with bit rate of 384 kbit/s from the encoder and reproduces the multi-channel audio signals for analog and digital outputs. The multi-processing of this audio codec using multiple DSPs is ensured by high speed transfer of date between DSPs through coordinating communication port activities with DMA coprocessors. Finally, some technical considerations are suggested to realize the problem of real-time operation, which are found out through the implementation of this codec using the MPEG-2 layer II sudio coding algorithm and the use of the hardware architecture with commercial multiple DSPs.