• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.121-126
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• 2009

Video poxy server which is located near clients can store the frequently requested video data in storage space in order to minimize initial latency and network traffic significantly. However, due to the limited storage space in video proxy server, an appropriate deletion algorithm is needed to remove the old video data which is not serviced for a long time. Thus, we propose an efficient video data deletion algorithm for video proxy server. The proposed deletion algorithm removes the video which has the lowest request possibility based on the user access patterns. In our algorithm, we arrange the videos which are stored in video proxy server according to the requested time sequence and then, select the video which has the oldest requested time. The selected video is partially removed in order to free up storage space in video poky server. The simulation results show that the proposed algorithm performs better than other algorithms in terms of the block hit rate and the number of block deletion.

• The Transactions of the Korea Information Processing Society
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• v.4 no.3
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• pp.685-697
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• 1997

A Viedo-on-Demand(VOD) service is a multimedia service that is realized by the rapid advance of computer and data communication techmologies. Basically, a VOD system is composed of a server and a number fo clients.The server stores and manages a large amount of digital moving picture data. Each slient sends an on-line requwet to the server and receives data for real-time displying. Many researches are performed on a VOD server using hard disks for the permanent video fata storage. However, a hard disk is less reliable and requires more storage cost than a massive storage device. Due to these resasons, a multi-level VOD system is proposed for using teh jukeboxes of optical disks as the permanent video storage,device. In this paper, we prpose the necessary software modules and protocols between the server and its clients for the implementation of the multi-level VOD server.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.157-162
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• 2002

Recently, location based services, which make use of location information of moving objects, have obtained increasingly high attention. The moving objects are time-evolving spatial objects, that is, their locations are dynamically changed as time varies. Generally, GIS server stores and manages the spatial objects, of which locations are rarely changed. The traditional GIS server, however, has a difficulty to manage the moving objects, due to the fact of locations being frequently changed and the trajectory information (past locations of moving objects) being managed. In this paper, we have designed a moving object server, which stores and manages the locations in order to support various location based services. The moving object server is composed of a location acquisition component, a location storage component, and a location query component. The contribution of this paper is that we integrate the each work for location acquisition, storage, and query into a moving objects server.

• Journal of the Korea Society of Computer and Information
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• v.16 no.10
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• pp.147-153
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• 2011

In this paper, we present a new video management technique using forward timeline to efficiently store and delete the videos on a local server. The proposed method is based on capturing the changing preference of the videos according to recentness, frequency, and playback length of the requested videos. For this purpose, we utilize the forward timeline which represents the time area within a number of predefined intervals. The local server periodically measures time popularity and request segment of all videos. Based on the measured data, time popularity and request segment, the local server calculates the mean time popularity and mean request segment of a video using forward timeline. Using mean time popularity and mean request segment of video, we estimate the ranking and allocated storage space of a video. The ranking represents the priority of deletion when the storage area of local server is running out of space and the allocated storage space means the maximum size of storage space to be allocated to a video. In addition, we propose an efficient storage space partitioning technique in order to stably store videos and present a time based free-up storage space technique using the expected variation of video data in order for avoiding the overflow on a local server in advance. The simulation results show that the proposed method performs better than other methods in terms of hit rate and number of deletion. Therefore, our video management technique for local server provides the lowest user start-up latency and the highest bandwidth saving significantly.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.4
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• pp.258-262
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• 2004

Storage over Ethernet (SoE) is a network storage architecture that allows direct attachment of existing ATA/ATAPI devices to Ethernet without a separate server. Unlike SAN, no server computer intervenes between the storage and the client hosts. We propose a SoE disk controller (SoEDC) amenable to low-cost, single-chip implementation that processes a simplified L3/L4 protocol and converts commands between Ethernet and ATA/ATAPI, while the rest of the complex tasks are performed by the remote hosts. Thanks to simple architecture and protocol, the SoEDC implemented on a single $4mm{\times}4mm$ chip in 0.18um CMOS technology achieves maximum throughput of 55MB/s on Gigabit Ethernet, which is comparable to that of a high-performance disk storage locally attached to a host computer.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.1365-1373
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• 1995

In this paper, we address the issues related to storage and retrieval of continuous media (CM)data we face in designing multimedia on-demand (MOD) storage servers. To support the two orthogonal factors of MOD server design, i.e., storage and retrieval of CM data, this paper discusses the techniques of disk layout, disk striping and real-time disk scheduling, which are integrated as a combined solution to the high- performance MOD storage subsystem. The proposed clustered striping technique enables either a multiple-disk or a parallel system to guarantee a continuous retrieval of CM data at the bandwidth required to support user playback rate by avoiding the formation of I/O bottlenecks.

• Journal of Information Processing Systems
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• v.7 no.1
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• pp.53-62
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• 2011

With the steady growth of mobile technology and applications, demand for more storage in mobile devices has also increased. A lightweight block-level protocol, Internet Advanced Technology Attachment (iATA), has been developed to deliver a cost-effective storage network solution for mobile devices to obtain more storage. This paper seeks to contribute to designing and implementing Load Balancing (LB), Network Monitoring (NM) and Write Replication (WR) modules to improve the protocol's scalability and data availability. LB and NM modules are invoked to collect system resources states and current network status at each associate node (server machine). A dynamic weight factor is calculated based on the collected information and sent to a referral server. The referral server is responsible to analyze and allocate the most ideal node with the least weight to serve the client. With this approach, the client can avoid connecting to a heavily loaded node that may cause delays in subsequent in-band I/O operations. Write replication is applied to the remaining nodes through a WR module by utilizing the Unison file synchronization program. A client initially connected to node IP A for write operations will have no hindrances in executing the relevant read operations at node IP B in new connections. In the worst case scenario of a node crashing, data remain recoverable from other functioning nodes. We have conducted several benchmark tests and our results are evaluated and verified in a later section.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.231-234
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• 2003

This paper designs and implements fault-tolerant server of meta server for shared filesystem (SANfs) in SAN environment. SANfs is the filesystem that many clients can share data in Network-attached storage in SAN environment and meta server is the server that processes file operation in SANfs. The focus of this paper is the implementation of fault-tolerant server of meta server in SANfs. In the event of a meta server, meta server failovers to a fault-tolerant server where its processing continues seamlessly. If meta server doesn't restore, fault-tolerant server searches reliable client and makes another fault-tolerant server and work as meta server. Heartbeat monitors meta server and shadow server and controls them.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.89-91
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• 1998

현대 사회의 정보 요구 증가와 편리함의 추구는 정보통신 기술의 발달과 함께 멀티미디어 데이터 서비스를 급증 시켰다. NOD 데이터의 경우 이러한 요구에 부합하므로, 많은 사용자를 가지게 될 것이며, 그에 따른 제반 요건으로 서버 구현에서 scalability, availability, reliability 등이 중요한 요건이다. 따라서 이러한 요건을 멀티미디어 데이터 특성을 이용한 저장 방법으로 만족시키려는 많은 연구가 있다. 그러나 NOD 시스템에 대한 연구는 미흡한 실정이며 clustered 환경에서의 New 데이터에 대한 연구는 거의 없다. VOD 데이터에 적합한 것으로 알려진 일반적인 저장 방법이 NOD 데이터에 반드시 적합한 것이 아니며, 본 논문에서는 기존에 연구된 데이터 저장 방법 중에서 NOD 데이터의 small volume, skewed popularity distribution 등의 특성을 고려하여 clustered storage server환경에 맞는 striping 정책을 찾는다.

• Proceedings of the Safety Management and Science Conference
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• 2002.11a
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• pp.157-163
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• 2002

Automated manufacturing systems are applied to shop floors as a tool for the increase of productivity and quality and the decrease of manufacturing lead times and industry accidents. One of the most important issue of the present day is the application of Internet. The development of Internet technologies makes manufacturing enterprises break spacial barriers between users and shop floors, and collect various field data in remote sites. In this research, an Internet-based remote control system for a small-sized automated storage and retrieval system is developed for the purpose of real-time monitoring and control of automatic production equipment. The developed system has a client-server architecture and transmits real-time images of the automated storage and retrieval system to a client by ar CCD camera connected to a server. Based on the transmitted images, the client sends commands to PLC of the server, and part storage and retrieval tasks are executed.