• The KIPS Transactions:PartB
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• v.9B no.2
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• pp.181-190
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• 2002

This paper proposes a motion-video multimedia system needed for computer applications like remote lecturing, distance learning, product demonstrations, and so on. The applications need a multimedia system which can author and play a motion-Video that is composed with computer screen images and audio continuously varing as time flows, not with real motion videos. Since the computer screen images are not like the real world video images in several rejects, MPEG is not competent as a compression algorithm for computer screen images raring continuously In this paper a new compression algorithm has been proposed, and a multimedia system that authors and plays a motion-video file which contains computer screen images and audio has been implemented. Also this paper shows the result of performance evaluation of both the compression algorithm and the multimedia system implemented in the paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2202-2211
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• 2006

EXT3NS is a special-purpose file system for large scale multimedia streaming servers. It is built on top of streaming acceleration hardware device called Network-Storage card. The EXT3NS file system significantly improves streaming performance by eliminating memory-to-memory copy operations, i.e. sending video/audio from disk directly to network interface with no main memory buffering. In this paper, we design and implement a buffer cache mechanism, called PMEMCACHE, for EXT3NS file system. We also propose a buffer cache replacement method called ONS for the buffer cache mechanism. The ONS algorithm outperforms other existing buffer replacement algorithms in distributed multimedia streaming environment. In EXT3NS with PMEMCACHE, operation is 33MB/sec and random read operation is 2.4MB/sec. Also, the buffer replacement ONS algorithm shows better performance by 600KB/sec than other buffer cache replacement policies. As a result PMEMCACHE and an ONS can greatly improve the performance of multimedia steaming server which should supportmultiple client requests at the same time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.4077-4091
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• 2017

This paper presents the design of a broadcasting scenario and system for an 8K-resolution content. Due to an 8K content is four times larger than the 4K content in terms of size, many technologies such as content acquisition, video coding, and transmission are required to deal with it. Therefore, high-quality video and audio for 8K (ultra-high definition television) service is not possible to be transmitted only using the current terrestrial broadcasting system. The proposed broadcasting system divides the 8K content into four 4K contents by area, and each area is hierarchically encoded by Scalable High-efficiency Video Coding (SHVC) into three layers: L0, L1, and L2. Every part of the 8K video content divided into areas and hierarchy is independently treated. These parts are transmitted over heterogeneous networks such as digital broadcasting and broadband networks after going through several processes of generating signal messages, encapsulation, and packetization based on MPEG media transport. We propose three methods of generating streams at the sending entity to merge the divided streams into the original content at the receiving entity. First, we design the composition information, which defines the presentation structure for displays. Second, a descriptor for content synchronization is included in the signal message. Finally, we define the rules for generating "packet_id" among the packet header fields and design the transmission scheduler to acquire the divided streams quickly. We implement the 8K broadcasting system by adapting the proposed methods and show that the 8K-resolution contents are stably received and serviced with a low delay.

• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.127-133
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• 2009

With advances in video technology, many researchers are interested in video quality assessment to prove better performance of proposed algorithms. Since human visual system is too complex to be formulated exactly, many researches about video quality assessment are in progressing. No-reference video-quality assessment is suitable for various video streaming services, because of no requested additional data and network capacity to perform quality assessment. In this paper, we propose a novel no-reference video-quality assessment method with the estimation of dynamic range distortion. To measure the performance, we obtain mean opinion score (MOS) data by subject video quality test with the ITU-T P.910 Absolute Category Rating (ACR) method. And, we compare it with proposed algorithm using 363 video sequences. Experimental results show that the proposed algorithm has a higher correlation with obtained MOS.

• Journal of Internet Computing and Services
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• v.15 no.6
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• pp.1-8
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• 2014

As the e-learning spreads widely and demands on the internet video service, transmitting video data for many users over the Internet becomes popular. To satisfy this needs, the traditional approach uses a tree structure that uses the video server as the root node. However, this approach has the danger of stopping the video service even when one of the nodes along the path has a some problem. In this paper, we propose a video-on-demand service that uses multiple paths. We add new paths for backup and speed up for transmitting the video data. We show by simulation experiments that our approach provides a high-quality of video service.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.959-962
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• 2005

Efficient video data storage and search techniques are essential for DVR-based security systems. We have designed appropriate data structures and search techniques for efficient image storage and search, in this study. The date and time can be saved and searched as a folder form. The overall system is designed for MPEG4 CODEC. It can handle variable sizes of frames (100bytes $^{\sim}$ 6Kbytes) produced by MPEG4 CODEC without errors. We also have developed image transmission techniques through inter-net networking.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.757-764
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• 2002

This Paper describes our experiences with the design and implementation of a networked multimedia information management system in an object-oriented framework for distributed multimedia applications, and an integrated QoS-resource negotiation protocol which has been applied to a video server in our networked multimedia infrastructure. The salient features of our framework to support efficient multimedia streaming are explained. Next the paper explores the challenges faced in integrating the proposed QoS negotiation policy into the framework.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.176-177
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• 2019

360 도 VR (Virtual Reality) 영상을 기존의 비디오처럼 재생하고 전송하기 위해서는 아직까지도 논의 되어야할 많은 문제들이 존재한다. 특히 보는 장면에 비하여 전방위의 영상을 보내야하는 VR 영상은 매우 큰 용량을 가질 수 밖에 없다. 그럼에도 불구하고 사용자의 불편함을 덜기 위해서는 HMD (Head-Mounted Displays) 의 빠른 반응 속도가 필요하다. 따라서 QER (Quality Emphasized Region)기반의 전송 기법은 영역별로 차별화된 화질의 영상을 전송하여 실감미디어의 몰입감을 유지하고 대역폭의 낭비를 줄이는 뷰포트 적응적 360 도 비디오 스트리밍 시스템 (Viewport-Adaptive 360-Degree Video Streaming System)의 일종으로 제안되었다. 그러나, 사용자의 시점 정보를 계산하기 위해서는 매 프레임마다 차원 변환을 위한 복잡하고 많은 계산이 필요하고, 이러한 중복된 계산은 시스템의 성능을 저하시키는 요인이 될 수 있다. 본 논문에서는 이러한 차원 변환에 따른 자원낭비를 줄이기 위하여 QER 선택을 위한 개선 방법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.05a
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• pp.536-539
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• 2020

길이 좁고 차도와 인도의 구분이 없는 골목길의 특성상 사각지대가 많고 보행자의 동선을 예측하기 힘들어 교통사고가 많이 발생하고 있다. 따라서 본 논문에서는 AI 를 활용, 영상 내 사물을 추적하여 골목길에서의 사고를 예방하는 시스템을 제안한다. 해당 시스템은 Object - Detection & Tracking 을 사용하여 보행자 및 차량을 식별·추적하여 두 개 이상의 사물이 동시에 교차로에 접근 시 사고 예방 알람을 발생시킨다. 이 시스템을 전국에 설치되어 있는 CCTV 에 활용하면 추가적인 비용과 설치 시간에 제한받지 않고 전국적으로 응용할 수 있을 것으로 기대된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.301-304
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• 2013

In this paper, to improve the fast boot and soft real-time for the responsiveness in Qplus with relative evaluation rather than an absolute evaluation using validated to perform the services actually used. Qplus is included soft real-time, fast booting, and file system technology. There is a development board that mounted on an embedded Linux and Qplus. AV (Audio / Video) group communications is ported on the development board for soft real-time multimedia streaming services and to evaluate the performance of communication. We performed three major evaluation such as booting time measurement experiment, own performance measurement experiments for soft real-time measurement experiment, and performance measurement experiments for via the network communication performance evaluation. They are a practical Qplus performance evaluation and analysis.