• The Transactions of the Korea Information Processing Society
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• v.4 no.3
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• pp.811-820
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• 1997

Disk arrays are using to enhance data trandfer rate and I/O performance in multimedia applications which need a high-performance storage device with large storage capacity and high-speed network.As performance varies with configuration and data layout scheme,disk array characteristic variables must be approrpriately deter-mined in desibning disk array archetecture for a speciffic applicatoin. In this paper,in order to design a disk array architecturte as a storage server of a small-scale VOD system,we evaluate performance of a disk array to chose the number of disks in the array,disk array cinfiguration,a degree of declustering for a given data block size of continous media file system and I/D request size through simulation.Simulation result shows that RAID level 5 with 5 disks ios a suitable candidate for the disk array architecture which privides MPEG-2 files with a rate of 6 Mbps,Moreover,we whow that stripe unit is 64 KB and a layout scheme is contigous placement.

• Journal of Broadcast Engineering
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• v.7 no.2
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• pp.114-125
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• 2002

Although there have been a lot of researches on a video abstraction algorithm, the video abstraction tool is necessary to correctly pick up some important shots in a video because the important shots might vary on the person's subjectivity. This paper proposes a video abstraction and search system for making a video abstraction automatically or manually. Proposed system has two main components, server and client. The server generates the Metadata and makes a video abstraction file. The description for video abstraction file is based on MPEG-7. Since proposed system has a function to manually correct the results of each step, the author could produce a good video abstraction easily and efficiently. The proposed system could be used to build a digital video library.

• Journal of Korea Multimedia Society
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• v.2 no.4
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• pp.459-467
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• 1999

With fully harnessing the functions provided by Windows NT, we suggest the generating method of RPL profile and the RPL protocol for remote booting on DL-NCS(Network Computing System for Diskless client PCs). This system can offer clients, without having hard disk, boot remotely Window 9x stored in server's hard disk and can share peripheral devices and application programs in the server side. For booting Window 9x from DL-NCS, twenty-five clients' PCs were set for simultaneous on and finally the PCs were booted in similar time interval compared to that from a desktop PC having local disk. This system was also experimented to the application programs. And this system can yield excellent networking environments. In sum, with using this DL-NCS, we can reduce the installing costs of peripheral device, recycle the lower grade PCs such as 486SX/DX, and save the budgets for software purchase.

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.421-431
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• 2007

Due to the rapid development of wireless communication technology, demands on data services in mobile computing environment are gradually increasing. In mobile computing environments, a mobile host began to use cache to overcome the weak point. Caching at mobile host could reduce the bandwidth consumption and query response time, but mobile host must maintain cache consistency. In this paper, we propose a cache consistency strategy to consider the period of data usage. The server allows an effective broadcasting by classifying data into two groups of periodic and non-periodic. By classifying the data, it prevent from elimination of cache after disconnection of periodic data by using expired time. By storing IR(Invalidation Report) messages, this scheme divides cached data by selection after disconnection. Consequently, we have shown much improvement in total consumption of bandwidth than the conventional scheme.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.1
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• pp.21-35
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• 2000

MIDAS-II is the storage system for BADA DBMS developed at ETRI. This paper describes the extension of MIDAS-II for incorporating the tertiary storage device such as an optical disk jukebox or a tape library, enabling MIDAS-II to function as a storage system of the data server that stores a massive amount of multimedia data. The MIDAS-II disk volume structure is extended to efficiently function as a volume for the tertiary storage device with multiple platters, which canstore huge amount of data of the order of tera bytes. The storage structure of the LOB is changed to efficiently manage the LOB data in the tertiary storage device. The data structures of the shared memory, the process structure, and the utilities in MIDAS-II are also extended to efficiently incorporating the tertiary storage device. The functionalities of each MIDAS-II API function are expanded to handle the tertiary storage device, while the prototypes of those functions are intact in order not to affect the existing application programs. The performance evaluation shows that the extended MIDAS-II works effectively with the tertiary storage device. All these extensions and the performance evaluation are conducted in the SunOS 5.4 environment.

• The KIPS Transactions:PartD
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• v.9D no.3
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• pp.477-486
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• 2002

vCard that is the electronic business card automates the exchange of personal information typically found on a traditional business card. vCard information contains not only simple text, but also graphics and multimedia data like pictures, company logos, Web addresses, and so on. This paper describes the design and implementation of Web-based vCard agent system for exchanging vCard, an electronic business card and searching another user's vCard in mobile phone environment. In today's business environment, such as that this information is typically exchanged on business cards. Our web agent system in this paper connect web server which provide vCard service and search, edit vCard information displayed by web browser of mobile phone and exchange vCard with another user through internet. Considering characteristics of wireless devices that have limited storage space, It also saves constructed XML documents that include user's informations in a web server and solves the security problem by exchanging not personal data or XML but encrypted directory name where XML document exits as exchanging vcard.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.1
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• pp.179-187
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• 2019

With the recent development of small computing devices, IoT sensor network can be widely deployed and is now readily available with sensing, calculation and communi-cation functions at low cost. Sensor data management is a major component of the Internet of Things environment. The huge volume of data produced and transmitted from sensing devices can provide a lot of useful information but is often considered the next big data for businesses. New column-wise compression technology is mounted to the large data server because of its superior space efficiency. Since sensor nodes have narrow bandwidth and fault-prone wireless channels, sensor-based storage systems are subject to incomplete data services. In this study, we will bring forth a short overview through providing an analysis on IoT sensor networks, and will propose a new storage management scheme for IoT data. Our management scheme is based on RAID storage model using column-wise segmentation and compression to improve space efficiency without sacrificing I/O performance. We conclude that proposed storage control scheme outperforms the previous RAID control by computer performance simulation.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.123-131
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• 2009

In this paper, we design ZigBee RF based framework for mobile web service on collected data by sensor node and transmitting data to data base by sensor network and remote sensing server through wireless connection. The proposed system is an integrated platform of sensor network for the sensor management and providing SOA based sensor web access. This paper combines SOA technology with sensor network. composes sensor node as web view, and provides high capability. extensiveness, reliability, and usability to the user who accesses to sensor web. The mobile message conversion module, SOAP message processing module. WSDL message generator, and mobile web service module is embodied for improving the capacity of the framework. The capacity evaluation of local wireless communication system which is proposed in this paper is analyzed through NS-2 simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.140-145
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• 2009

Recently, lots of research activities have been carried out to provide advanced smart control functions applying a computer networking technology to telemeter/telecontrol systems. In this paper, we suggest client/server architecture with specially designed remote and local control software for applicant those to greenhouse model. The server system collects and integrates various datas related sensor or actuator, and stores in database maintaining high quality of remote I/O control operation. Where as the client system simply operation such as control panel on the internet web browser. Implemented system well communicate interactively both monitoring and control status of greenhouse including multimedia informations. In this study we also analyze the extent of the performance enhancement in terms of overall throughput and data transfer time effected by packet size.

• Proceedings of the Korea Database Society Conference
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• 2001.11a
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• pp.536-554
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• 2001

인터넷 이용자의 증가와 멀티미디어 등 대용량 콘텐츠에 대한 수요의 증가로 인해 데이터 트래픽은 기하 급수적으로 늘어나는 데 비해 네트웍 성능향상에 대한 투자는 이에 미치지 못함으로서 결과적으로 인터넷은 트래픽의 병목현상, 즉 정체현상이 발생하게 되었으며 점차 그 정도가 심해지고 있다. 이 문제를 해결하기 위해 제안하는 방안이 바로 전략적 CDN(Content Delivery Network) 이다. 현실적으로, 본 연구는 물리적인 망 증설만으로는 트래픽 체증 문제를 해결하기는 어려우므로 주요 ISP 네트웍에 전략적 캐시서버를 설치하여 CP의 콘텐츠를 각 ISP 네트웍마다 분산하여 저장하고 이용자의 요청 시 이용자의 인터넷 회선이 물려 있는 ISP 네트웍에서 바로 콘텐츠를 전송하여 데이터 손실과 속도 저하 등의 문제를 해결하는 CDN의 구성과 그 효과를 실증적으로 밝혔다.