• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.2080-2089
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• 1997

Recent evolution in compute technology makesthe multimedia processing widely availiable. Conventional storage systems do not meet the requirements of multimedia data. Several approaches were suggested to improve disk storing methods for them. Bocheck proposed a disk partitioning technique for multiple steams assuming that all steams have same retrieval intervals with the same amount data for each access. While Bocheck's one provides a good method for same period, it does not consider the case of different periods of continous media streams. This paper proposes a new partitioning technique in which a fixed number of blocks are assigned for stresms with different retrieval periodicity. The analysis shows this problem is the same as the one scheduling the steams into a given sequence. The simulation was done to compare the proposed m-sequence merge method with the conventional Scan-EDF and Partitioning methods.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.529-532
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• 2005

In anomaly intrusion detection, how to model the normal behavior of activities performed by a user is an important issue. To extract the normal behavior as a profile, conventional data mining techniques are widely applied to a finite audit data set. However, these approaches can only model the static behavior of a user in the audit data set This drawback can be overcome by viewing the continuous activities of a user as an audit data stream. This paper proposes a new clustering algorithm which continuously models a data stream. A set of features is used to represent the characteristics of an activity. For each feature, the clusters of feature values corresponding to activities observed so far in an audit data stream are identified by the proposed clustering algorithm for data streams. As a result, without maintaining any historical activity of a user physically, new activities of the user can be continuously reflected to the on-going result of clustering.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.893-901
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• 2013

This paper suggests a method of developing live media streaming service through Linux server system on android system environment. The android application constructed in the experiment is able to record media while sending it to Linux server. Generated real time media data is send to linux server through Multipart Request class of Apache Tomcat server constructed on Linux system. Also in this research, by utilizing Android video player and media player class, development of android application structures was accomplished, which has methods of; playing live media stream data on video server, or playing live media stream data while saving stream data in cache. The structure and function of suggested system and application is confirmed by series of experiments.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.904-907
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• 2013

최근 정보통신기술이 하루가 다르게 발전함에 따라 하루에도 수많은 데이터가 흘러나오는 최근의 추세이다. 정형 데이터 뿐 아니라 비정형 데이터 분석까지 진행하는 최근의 추세에 맞춰 현 빅데이터 기술 동향을 분석한다. 빅데이터 시대를 맞아 기존의 데이터웨어하우스(DW)와 발전된 데이터웨어하우스(DW) 어플라이언스에 대해 분석하고 향후 발전 전망과 방향을 제시한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1336-1348
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• 2009

In this paper, we propose an energy-aware multi-tree video multicast scheme for wireless ad hoc networks. Some network nodes may have energy enough to receive and forward the whole video content whereas some may not. Even though the video quality may vary depending on the remaining energy, our scheme enables the low-energy nodes to join the video multicast session. The video stream is split into a set of multiple and independent descriptions by MDC (Multiple description coding) scheme. Each description corresponds to a substream and number of substreams determine the video quality. The member nodes determine how many substreams it would receive depending on the remaining energy and expected amount of packets per substream. So does the intermediate tree nodes. That builds a tree per substream and multiple trees per session. The data source disseminates each substream through corresponding tree. The video quality of the member nodes varies according to number of participating trees. We evaluate the performance of our scheme by simulation. Our scheme showed better peak signal to noise ratio and extended the lifetime of the network nodes compared with MAODV, which builds a single tree, and MT-MAODV, which builds multiple trees but does not consider the available energy.

• Journal of the Korean Data and Information Science Society
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• v.22 no.1
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• pp.19-27
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• 2011

Recommendation systems are developed to overcome the problems of selection and to promote intention to use. In this study, we propose a recommendation system using adjacency data according to user's behavior over time. For this, the product adjacencies are identified from the adjacency matrix based on graph theory. This research finds that there is a trend in the users' behavior over time though product adjacency fluctuates over time. The system is tested on its usability. The tests show that implementing this recommendation system increases users' intention to purchase and reduces the search time.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.21 no.10
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• pp.31-35
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• 2003

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.317-320
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• 2000

본 논문은 양방향 디지털 텔레비전에서 데이터의 전송을 위해 데이터 전송 스트림을 생성하는 스트리밍 서버의 구조 및 기능, 시스템 구현에 관해 서술한다 이 시스템은 ATSC 데이터 방송 규격에서 정의하는 비동기데이터, IP 데이터그램, 동기 및 동기화된 데이터의 전송 기능을 지원하며 국제 전송 규격인 MPEG-2 시스템규격 및 ATSC 데이터 방송 규격에 따라 PC 환경하에서 소프트웨어적으로 구현 되었다.

• Journal of KIISE:Databases
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• v.37 no.1
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• pp.1-11
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• 2010

Recently, there has been a growing interest in the processing of continuous queries over multiple data streams. When the arrival rates of tuples exceed the memory capacity of the system, a load shedding technique is used to avoid the system becoming overloaded by dropping some subset of input tuples. In this paper, we propose an effective load shedding algorithm for multi-way windowed joins over multiple data streams. Most previous load shedding algorithms estimate the productivity of each tuple, i.e., the number of join output tuples produced by the tuple, based on its "join attribute value" and drop tuples with the lowest productivity. However, the productivity of a tuple cannot be accurately estimated from its join attribute value when the join attribute values are unique and do not repeat, or the distribution of the join attribute values changes over time. For these cases, we estimate the productivity of a tuple based on its "arrival order" on data streams, rather than its join attribute value. The proposed method can effectively estimate the productivity of a tuple even when the productivity of a tuple cannot be accurately estimated from its join attribute value. Through extensive experiments and analysis, we show that our proposed method outperforms the previous methods in terms of effectiveness and efficiency.

• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.214-221
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• 2007

In this paper, we presents conformance test tools for the broadcast web site (BWS) service which is one of the data services for terrestrial digital multimedia broadcasting (T-DMB). First, the methodology for the conformance test is established for both transmitters and receivers of T-DMB BWS services. The test tools consist of three parts: BWS bitstream analyzer, BWS reference decoder (software) module, and BWS test bitstreams. For testing transmitted BWS bitstreams, we developed the bitstream analyzer. For testing BWS receivers, we developed the reference Ifecoder module and created the test bitstreams. Actually the bitstream analyzer developed in this paper was used for the verification of the test bitstreams. The same test bitstreams are fed to a BWS decoder module under test and the reference decoder module and the results from the two are compared for verification. The test tools can be used for the test of all the protocol and textual/image specifications related to BWS including MOT protocol, HTML, PNG, MNG, JPEG, and Ecma Script.