• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.61-64
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• 2001

초저속 고압축 비디오는 고압축 부호화를 위해 주로 P-픽쳐 부호화 방법을 사용한다. P-픽쳐는 현재 프레임과 이전 프레임간의 데이터 의존성이 높기 때문에 전송시 패킷 손실이 발생할 경우 복원 영상에 심각한 화질 열화를 야기할 수가 있다. 따라서 본 논문에서 초저속 고압축 비디오 데이터에 대한 미디어내 동기화를 위해 TCP 기반 멀티스트림 생성 기법을 제안한다. 제안한 기법은 TCP 기반으로 신뢰성 있는 전송이 가능하며, 멀티 스트립을 통해 병렬 전송이 가능하므로, TCP 기반에서 네트워크 트랙픽에 의해 발생하는 지터에 민감하지 않아 최선의 서비스를 제공할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.7-9
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• 2005

본 논문에서는 모바일 무선 네트워크 상에서 효율적으로 XML문서를 방송하기 위한 기법을 제안한다. 이를 위해 XML 문서의 구조정보를 무선 방송 데이터의 색인으로 활용하여 XML문서를 스트링으로 재구성한다. 방송되는 XML스트링의 색인은 XML 경로 요약을 이용하여 축약된 형태로 표현하며, 구조 정보를 XML스트림의 색인으로 사용하기 위해 XML문서는 구조정보와 컨텐츠 정보로 분리한다. 축약된 색인을 이용하여 각 클라이언트는 방송되는 XML 스트림에 대하여 지역적으로 질의를 수행함으로써 전체 XML문서 중 자신이 원하는 정보만을 수신한다. 성능평가를 통해 제안하는 기법이 접근 시간 및 튜닝시간에서 많은 이득을 볼 수 있음을 보인다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.821-825
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• 2002

In the paper, we described a new visual telephone system to solve the unsatisfactory items of existing systems based on H.320. The system has a differential task interrupt transfer feature for real time video phone service. Owing to the result of interrupt transfer of different speed according to the time critical degree of tasks, the flow of audio and video data stream can be kept as constant speed.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1043-1046
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• 2004

본 논문에서는 MPEG-4 스트림의 디지털 저작권 관리(DRM)를 위한 암호화 방법을 제안한다. MPEG-4는 멀티미디어 스트리밍을 위한 표준이며 MPEG-4 파일 포맷에 따라 저장된다. 인가된 사용자들만 접근이 가능하도록 MPEG-4 파일 포맷으로부터 추출된 I-VOP, P-VOP의 매크로 블록(MB)들과 모션 벡터(MV)들을 암호화 하는 3가지 방법을 설계하였고, MPEG-4 데이터의 암호화에는 DES(Data Encryption Standard)를 사용하였다. 이러한 암호화 방법을 기반으로 MPEG-4 데이터 스트리밍을 위한 인터넷 방송 서비스용 DRM 솔루션을 구현하고, 최적의 암호화 방법을 선택하기 위해 복호화 속도 및 영상의 품질을 비교하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.249-252
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• 2009

Recently, it is possible for users to acquire necessary data easily as the various schemes of the searching information are developed. Since these data rise continuously like stream data, it is required to extract the appropriate data for the user's needs from the mass data on the internet. In the traditional scheme, they are acquired by processing the user queries after the occurred data are stored at a database. However, it is inefficient to process the user queries over the large volume of continuous data by using the traditional scheme. In this paper, we propose the query processing scheme to extract the data efficiently for the user requirements from the large volume of continuous data. On the proposed scheme, we present the Event-Profile Model to define the data occurrence on the internet as the events and the user's requirements as the profiles. We also show the filtering scheme to process the events and the profiles efficiently.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.147-157
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• 2018

Recently, with the advancement of network technologies, and the activation of IoT and social network services, many graph stream data have been generated. As the relationship between objects in the graph streams changes dynamically, studies have been conducting to detect or analyze the change of the graph. In this paper, we propose a scheme to incrementally detect frequent patterns by using frequent patterns information detected in previous sliding windows. The proposed scheme calculates values that represent whether the frequent patterns detected in previous sliding windows will be frequent in how many future silding windows. By using the values, the proposed scheme reduces the overall amount of computation by performing only necessary calculations in the next sliding window. In addition, only the patterns that are connected between the patterns are recognized as one pattern, so that only the more significant patterns are detected. We conduct various performance evaluations in order to show the superiority of the proposed scheme. The proposed scheme is faster than existing similar scheme when the number of duplicated data is large.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.769-782
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• 2009

Stereoscopic video service is one of the most widely adopted technologies for 3-Dimensional technology. However, the stereoscopic video service has not been penetrated into the market since there does not exist a proper transmission method even though the conventional MPEG-2 Transport Stream (TS) has support for broadcast service of mono-scopic video contents. This is partly because the MPEG-2 TS does not support displaying a stereoscopic video content which consists of several composition types widely used in the market. This paper proposes the new MPEG-2 TS specification suitable for transmitting and displaying stereoscopic video contents. In order to show feasibility of the proposal, this paper describes an end-to-end system which is implemented with consideration of the method how to multiplex and de-multiplex stereoscopic video contents as well as keeping backward compatibility with the traditional MPEG-2 TS.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.75-84
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• 2017

It becomes more and more more important for the storage that supports high speed recording and stable access from network environment. As one field of basic science which produces massive astronomical data, VLBI(: Very Long Baseline Interferometer) is now demanding more data writing performance and which is directly related to astronomical observation with high resolution and sensitivity. But most of existing storage are cloud model based for the high throughput of general IT, finance, and administrative service, and therefore it not the best choice for recording of big stream data. Therefore, in this study, we design storage system optimized for high performance of I/O and concurrency. To solve this problem, we implement packet read and writing module through the use of libpcap and pf_ring API on the multi core CPU environment, and build a scalable storage based on software RAID(: Redundant Array of Inexpensive Disks) for the efficient process of incoming data from external network.

• Journal of Korea Multimedia Society
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• v.14 no.9
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• pp.1152-1164
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• 2011

Stock price is stream data to change continuously. The characteristics of these data, stock trends according to flow of time intervals may differ. therefore, stock price should be continuously prediction when the price is updated. In this paper, we propose the new prediction system that continuously predicts the stock price according to the predefined time intervals for the selected stock item using HTM model. We first present a preprocessor which normalizes the stock data and passes its result to the stream sensor. We next present a stream sensor which efficiently processes the continuous input. In addition, we devise a storage node which stores the prediction results for each level and passes it to next upper level and present the HTM network for prediction using these nodes. We show experimented our system using the actual stock price and shows its performance.

• The KIPS Transactions:PartD
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• v.14D no.5
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• pp.483-490
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• 2007

Recently mining techniques that analyze the data stream to discover potential information, have been widely studied. However, most of the researches based on the support are concerned with the frequent event, but ignore the infrequent event even if it is crucial. In this paper, we propose SM-AF method discovering association rules to an abnormal event. In considering the window that an abnormal event is sensed, SM-AF method can discover the association rules to the critical event, even if it is occurred infrequently. Also, SM-AF method can discover the significant rare itemsets associated with abnormal event and periodic event itemsets. Through analysis and experiments, we show that SM-AF method is superior to the previous methods of mining association rules.