• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.4
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• pp.63-72
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• 2007

In this paper, we propose a novel reconfigurable coprocessor for multimedia mobile terminals. Because most of multimedia operations require fast operations of large amount of data in the limited clock frequency, it is necessary to enhance the performance of the embedded processor that is widely used in current multimedia mobile terminals. Therefore, we proposed and have designed the coprocessor which had the ability of fast operations of multimedia data. The proposed coprocessor was not only reconfigurable, but also flexible and expandable. The proposed coprocessor has been designed by using VHDL and compared with previous reconfigurable coprocessors and a commercial embedded processor in architecture and speed. As a result of the architectural comparison, the proposed coprocessor had better structure in terms of hardware size and flexibility. Also, the simulation results of DCT application showed that the proposed coprocessor was 26 times faster than a commercial ARM processor and 11 times faster than the ARM processor with fast DCT core.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.5
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• pp.213-217
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• 2001

Excessive memory buffer requirement in continuous media playback is a serious impediment of wide spread usage of on-line multimedia service. Skewed access frequency of available video files provides an opportunity of re-using the date blocks which has been loaded by one session for later usage. We present novel algorithm which minimizes the buffer requirement in multiple sessions of multimedia playbacks. In continuous media playback originated from the disk, a certain amount of memory buffer is required to synchronize asynchronous disk. Read operation and synchronous playback operation. As aggregate playback bandwodth increases, larger amount of buffer needs to be allocated for this synchronization purpose. The focus of this work is to study the asymptotic behavior of the synchronization buffer requirement and to develop an algorithm coping with this excessive buffer requirement under bandwidth congestioon. We argue that in a large scale continuous media server, it may not be necessary to read the blocks for each session directly from the disk. The beauty of our work lies in the fact that it dynamically adapts to disk utilization of the server and finds the optimal way of servicinh the individual sessions while minimizing the overall buffer space requirement. Optimality of the proposed algorithm is shown by proof. The effectiveness and performance of the proposed scheme is examined via simulation.

• The Transactions of the Korea Information Processing Society
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• v.5 no.8
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• pp.1960-1971
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• 1998

The researches and developments to provide multimedia communication services such as Video on Demand(VoDJ), real time video phonc and multipoint vidco conferencing on broadband ISDN environmcnts have been proceeded with activity. Specifications for Vol) services which is worked by Digital Audio-Visual Council(DAVIC) to support detail technologies including total service system that is consist of VoD server. delive[\! networl, and Set-Top Box(STB) had been already finished and ITU-T SG16 also recommended the standards of H.300 series terminal aspects for conversational multimedia services, But the architectures of multimedia tenninals recommended and specified by these organizations do not have an efficient st11lcture to provide all of retrieval, distrihution and conversational service due to a different point of view about multimedia terminals and services. In this paper, we analyzed the recornmendatio!E and the specifications of intemational public and private organizations like lTU-T, DAVIC and ATM forum. As a result of these analysis. we propose an efficient terminal architecture, and then we have designed, lmplemented the multimedia communication terminal for offering VoI) and real- time conversation ,,, functional module test according to the individual commumication service session and confirined the validiry or terminal implemented to be used on broadband ISDK environments.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.1
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• pp.9-20
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• 2005

Recently, the MPEG-7 standard a multimedia content description standard is wide]y used for content based image/video retrieval systems. However, since the descriptors standardized in MPEG-7 are usually multidimensional and the problem called 'Curse of dimensionality', previously proposed indexing methods(for example, multidimensional indexing methods, dimensionality reduction methods, filtering methods, and so on) could not be used to effectively index the multimedia database represented in MPEG-7. This paper proposes an efficient multimedia data indexing mechanism reflecting the characteristics of MPEG-7 visual descriptors. In the proposed indexing mechanism, the descriptor is transformed into a histogram of some attributes. By representing the value of each bin as a binary number, the histogram itself that is a visual descriptor for the object in multimedia database could be represented as a bit string. Bit strings for all objects in multimedia database are collected to form an index file, bitmap index, in the proposed indexing mechanism. By XORing them with the descriptors for query object, the candidate solutions for similarity search could be computed easily and they are checked again with query object to precisely compute the similarity with exact metric such as Ll-norm. These indexing and searching mechanisms are efficient because the filtering process is performed by simple bit-operation and it reduces the search space dramatically. Upon experimental results with more than 100,000 real images, the proposed indexing and searching mechanisms are about IS times faster than the sequential searching with more than 90% accuracy.

• Proceedings of the KIEE Conference
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• 2006.10b
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• pp.194-198
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• 2006

전국전인 초고속통신망이 구축되면서 인터넷을 통해 서비스되는 정보도 과거의 텍스트 기반의 서비스에서 정지영상, 동영상, 음성 등과 같은 멀티미디어 서비스가 주류를 이루고 있다. 웹캠이나 CCD 카메라로 촬영한 영상을 인터넷을 통해서 실시간으로 서비스할 수 있는 기술이 개발되면서 이를 이용하여 모니터링 서비스, 원격감시 시스템, 다자간 화상회의시스템, 출입관리, 동영상을 스트리밍 서버를 이용한 서비스, 인터넷 방송 등 다양한 분야에서 사용되고 있다. 본 연구에서는 웹 캠나 CCD 카메라를 통해 획득한 영상 중 필요로 하는 부분을 저장하여 향후에 사용할 수 있도록 하는 시스템 을 개발하는 것으로 동화상 캡처 드라이버와 인터페이스 처리 부분, 데이터 분석 처리 부분, 데이터 처리 부분을 C++ 프로그램을 사용하여 개발하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.619-621
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• 2000

최근 인터넷 기술의 발달로 인한 실시간 인터넷 동영상 서비스 등 인터넷을 이용한 방송사업이 활성화되어지고 이에 부가적으로 애니메이션이 감각적 서비스를 지원하고 있는 실정이나 고가의 모션캡쳐 시스템을 통한 캡쳐된 좌표를 적절한 보정을 한 후에 캐릭터를 움직이는 방법으로 이루어지고 있다. 이러한 모션캡쳐 시스템을 통한다면 시스템 및 장비 자체가 고가이고 또한 실시간으로 처리하기 위하여는 좌표값 보정 등이 필요하지만 본 논문에서 제안하는 좌표 추출 및 추적 기법을 이용하여 저가의 가정용 멀티미디어 오버레이 캡쳐보드와 CCD 카메라를 통하여 영상을 캡쳐하고 캡쳐된 영상좌표와 실험용 GDI object를 링크시켜 실시간으로 사람의 입술의 움직임 모양대로 애니메이션이 립싱크되어서 움직여지는 것을 볼 수 있으며, 더 나아가서 외화의 우리말 더빙시 영상처리를 통한 정교한 화면 더빙 및 가상 캐릭터를 이용한 사이버 미팅가지 가능할 것이다.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.71-81
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• 2011

In order to easily create video tutorials, the algorithm is needed that video camera recording, white board images, video attachments, and document data are combined in real-time. In this study, we implemented the video lecture content creation system using wavelet-based lossless compression to composite multimedia objects in real-time and reproduce the images. Using commercially available PC can be useful when lecturers want to make video institutional contents, it can be operated easily and fastly. Therefore, it can be very efficient system for e-Learning and m-Learning. In addition, the proposed system including multimedia synthesis technology and real-time lossless compression technology can be applied to various fields, different kinds of multimedia creation, remote conferencing, and e-commerce so there are highly significant.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.250-258
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• 2003

Recently, the transition from conventional analog broadcasting to digital broadcasting has been proceeding as a result of the advance in digital multimedia broadcasting technique. In radio broadcasting, Eureka-147 DAB(Digital Audio Broadcasting) was decided as the standard system of digital radio broadcasting in Korea. In addition to CD quality audio, a variety of data services and excellent performance in mobile reception can be served by DAB, and DAB was evolved into DMB(Digital Multimedia Broadcasting) in Korea for the purpose of emphasizing moving picture multimedia service by DAB. In case of digital broadcasting, it is absolutely essential to measure the BER(Bit Error Rate) in the received signal in order to evaluate the coverage obtained by a transmitter and the quality of the received signal. In this paper, we propose efficient subchannel data structure and BER measurement algorithm. and then verify it by laboratory experiments. With a proposed method, the synchronization for BER measurement is easily obtained and especially the exact results can be obtained by classifying the lost bits which are included in the reception-failed CIFs(Common Interleaved Frame) into errors. This makes the proposed BER measurement system especially appropriate to DMB in which the frequent changes in channel status caused by mobile reception environment exist.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.5_6
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• pp.223-231
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• 2003

Video-on-Demand (VOD) service needs high resource consumption because of high bandwidth and long playback duration which are characteristics of multimedia. Various techniques such as Patching and Channel-Reserving Patching have been proposed to reduce the demand on the network-I/O bandwidth. Patching allows new clients to join an existing multicast for realization of true VOD, and Channel-Reserving Patching reserves the part of total channel capacity of video server in order to serve the requests for popular videos on which requests of users concentrate. To improve the performance of Channel-Reserving Patching, we propose the method that determines the reserved channel capacity of video server for the popular videos in this paper. The performance of our method is evaluated in terms of average servile latency, defection ratio and fairness through simulation, and is compared with those of Patching and another Channel-Reserving Patching.

• Journal of Broadcast Engineering
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• v.1 no.1
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• pp.14-21
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• 1996

Wireless CATV is a type of CATV that offers its subscribers a mix of microwave channel by transmitting the programming over MMDS frequency. The benefit of wireless CATV can be made available in areas of scattered population and other areas where it is too expensive to build a traditional cable station. Also, due to the lower cast of building a wireless cable station, saving can be passed on to the subscribes. Therefore, in this paper 28[GHz] band bidirectional analog wireless system was proposed. When fully implemented, wireless CATV may have as many as 33 channels of broadcast. Further, if digital wireless CATV is used 150 to 300 channels may become available.