• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(4)
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• pp.207-210
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• 2000

We propose a content based watermarking technique in multimedia management system. In the proposed technique, a content description technique of MPEG-7 for the multimedia database is adopted into a watermarking technique. With multimedia features described by MPEG-7 standard, we propose a novel watermarking technique where MPEG-7 descriptors are regarded as perceptually significant portions. The watermark is embedded in cooperating with multimedia features such as MPEG-7 descriptor. To verify the feasibility and performance of proposed watermarking technique, experiments with the MPEG-7 database are performed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1051-1052
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• 2008

As the mobile phone has multi functions and high performance, multimedia processors have an important roles in handsets. Recently high resolution camera (above 5M pixels), HD Camcording and beautiful UI which Using OpenVG or OpenGL are adopted in mobile phone. So we are introduced the function multimedia processor and guide to mobile phone engineers to meet multimedia features.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2019년도 춘계학술발표대회
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• pp.605-607
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• 2019

최적의 사진을 얻기 위해 시각적 방해요소들을 개선할 수 있는 기술들을 조사했다. CNN 모델을 활용한 HDR 이미지 재구성, 방해물과 원하는 피사체와의 깊이 차이에서 생기는 시차를 이용한 이미지 처리를 사용해서 시각적 방해요소를 개선하는 알고리즘을 기술했다.

• Journal of Information Processing Systems
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• 제4권1호
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• pp.1-8
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• 2008

In this paper, we discuss the use of fragmented bandwidth to improve the performance of staggered striping in a multimedia system. It is observed that potential disruptions can occur when nonconsecutive idle disks are used for displaying multimedia objects. We have identified useful retrieval patterns and shown that with proper selections of fragmented disks and a simple buffering scheme, disruptions can be easily eliminated.

• 한국경영과학회지
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• 제30권2호
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• pp.29-40
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• 2005

In this research, we propose packet scheduling algorithm considering different QoS characteristics of real-time traffic and non-real-time traffic in the next generation wireless communication system serving the multimedia traffic and a new efficient framing method cooperated with this packet scheduler. When the selected traffic classes of the selected users are transmitted, our proposed framing method can increase the number of serviced traffic classes by mixing the many different traffic classes within one frame considering data rate decided by the allocated AMC (Adaptive Modulation and Coding) option. Using this proposed method, the fairness among the traffic classes can be achieved and the system performance for total throughput and delay can be enhanced. Simulations are performed to analyze the performance of the proposed framing method. Our proposed packet scheduler and framing method will be applied to the next generation multimedia wireless communication system serving many traffic classes.

• Journal of Computing Science and Engineering
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• 제9권3호
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• pp.134-141
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• 2015

In on-demand multimedia streaming systems, streaming techniques are usually combined with proxy caching to obtain better performance. The patch streaming technique has no start-up latency inherent to it, but requires extra bandwidth to deliver the media data in patch streams. This paper proposes a proxy caching technique which aims at reducing the bandwidth cost of the patch streaming technique. The proposed approach determines media prefixes with high patching cost and caches the appropriate media prefix at the proxy/local server. Herein the scheme is evaluated using a synthetically generated media access workload and its performance is compared with that of the popularity and prefix-aware interval caching scheme (the prefix part) and with that of patch streaming with no caching. The bandwidth saving, hit ratio and concurrent number of clients are used to compare the performance, and the proposed scheme is found to perform better for different caching capacities of the proxy server.

• 한국멀티미디어학회논문지
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• 제20권10호
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• pp.1619-1627
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• 2017

Image hashing has been successfully applied for the problems associated with the protection of intellectual property, management of large database and indexation of content. For a reliable hashing system, improving hash matching accuracy is crucial. In order to improve the hash matching performance, we propose an asymmetric hash matching method using the psychovisual threshold, which is the maximum amount of distortion that still allows the human visual system to identity an image. A performance evaluation over sets of image distortions shows that the proposed asymmetric matching method effectively improves the hash matching performance as compared with the conventional Hamming distance.

• 한국멀티미디어학회논문지
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• 제3권6호
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• pp.643-651
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• 2000

초고속 인터넷의 멀티미디어 서비스 통합에 대한 해결책으로 ATM네트워크 기술이 널리 사용되고 있다. 특히 ABR과 UBR 서비스 클래스는 데이터 애플리케이션을 지원하기 위해 발전되었다. 본 논문에서는, UBR 서비스 상에서는 빠른 재전송과 회복 (FRR) 및 Nagle's 알고리즘의 적용과, ABR 서비스 강에서는 EFCI 스위치 파라미터 조절을 통한 TCP 데이터의 전송성능 향상 효과를 시뮬레이션을 통해 분석하였다. 본 연구의 결과로, ATM 네트워크 상에서 TCP의 성능향상은 TCP 파라미터의 조절과 효과적인 스위치 파라미터의 설정을 통해 가능해 짐을 알 수 있었다.

• Journal of Communications and Networks
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• 제8권3호
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• pp.297-305
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• 2006

High-rate wireless personal area network (HR-WPAN) has been standardized by the IEEE 802.15.3 task group (TG). To support multimedia services, the IEEE 802.15.3 TG adopts a time-slotted medium access control (MAC) protocol controlled by a central device. In the time division multiple access (TDMA)-based wireless packet networks, the packet scheduling algorithm plays a key role in quality of service (QoS) provisioning for multimedia services. In this paper, we propose an adaptive cross-layer packet scheduling method for the TDMA-based HR-WPAN. Physical channel conditions, MAC protocol, link layer status, random traffic arrival, and QoS requirement are taken into consideration by the proposed packet scheduling method. Performance evaluations are carried out through extensive simulations and significant performance enhancements are observed. Furthermore, the performance of the proposed scheme remains stable regardless of the variable system parameters such as the number of devices (DEVs) and delay bound.

• 한국컴퓨터정보학회논문지
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• 제14권7호
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• pp.113-121
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• 2009

DRM이 최근에 많은 사이트에서 제거되어짐에 따라 비디오 서버 상에서 콘텐츠 보호는 중요해졌다. 그러나 기존에 존재하는 보호 방법들은 한계 들을 가지거나 스트리밍 성능을 저하시키므로 사용되어지지 않는다. 본 논문은 eCryptFS와 SELinux를 사용하는 콘텐츠 보호 방법을 제안하고 다양한 벤치마크들을 사용하여 제안한 방법의 성능을 측정한다. 그런 후 본 논문은 제안한 방버이 다른 성능 들은 저하시키지만 스트리밍 성능은 저하시키지 않아서 콘텐츠 보호를 위하여 사용할 수 있다는 것을 증명한다.