• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.128-133
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• 2005

Respond time and processing rate representing how many tasks can be done during an unit time in a client/server environment are generally use for measuring the performance of computers. In this paper, we suggest a window buffer managing scheme based on a window with many of short-term sliced slots where a media stream is allocated and deallocated into them so that it can maximize the utilization ration of the limited buffer on a multimedia server. And we also propose a buffer substitution scheme for reducing I/O times of a multimedia server by counting re-reference time point about a used block and then it can be reused by the next consecutive media stream.

• The KIPS Transactions:PartA
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• v.11A no.7 s.91
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• pp.511-520
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• 2004

A peer-to-peer model is very useful in solving the server link bottleneck problem of a client-server model. In this work, we discuss the problems of distributing multimedia content over peer-to-peer network. We focus on two problems in peer-to-peer media content distribution systems. The first is the transmission scheduling of the media data for a multi-source streaming session. We present a sophisticated scheduling scheme called fixed-length slotted scheduling, which results in minimum buffering delay. The second problem is on the fast distribution of media content in the peer-to-peer system that is self-growing. We propose a mechanism accelerating the speed at which the system's streaming ca-pacity increases, called FAST.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.67-70
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• 2014

본 논문에서는 아두이노를 이용하고 SMS와 PHP를 기반으로 구축된 인터렉티브 종이비행기 게임시스템을 설계하고 구현한다. 본 시스템은 LCD가 설치된 건물과 센서가 부착되어 물체가 들어오면 인식할 수 있는 각기 독립된 4개의 방, 게임 사용자의 문자 메시지를 읽고 출력하는 용도의 프린트와 개인서버로 이루어진다. 설계단계는 PHP를 이용한 웹 서버를 통해 사용자가 보낸 문자 메시지를 읽어 오는 첫 번째 단계, 사용자가 보낸 문자메시지의 내용을 프린트를 통해 출력하는 단계, 출력된 내용의 프린트물이 비행기로 접혀 센서가 부착된 각기 다른 4개의 방으로 들어갔을 때 프린트에 적힌 문자메시지의 내용이 LCD에 출력되는 단계로 이루어진다.

• The KIPS Transactions:PartB
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• v.11B no.1
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• pp.91-98
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• 2004

This paper proposes how to support various media on online conversational activity using XML(extensible Markup Language). The method converts media information into XML based messages and handles alike conventional text based messages. The XML based messages are unified to an XML document, and then a HTML document is generated using the XML and an XSLT documents in a server. A user in each client can play or present media through the hyperlink that is associated media information on the HTML document. The suggested method supports use of various media (text, image, audio, video, documents, etc) and efficient maintenance of font size, color, and style on messages according to extension and modification of XML tags. For application, this paper implemented the system to support media that has client and server architecture on online conversational activity. A user in each client inputs text or media based message using JAVA applet and servlet on the system, and conversational messages on every users' interfaces are automatically updated whenever a user inputs new message. Media on conversational messages are played or presented according to a user's click on hyperlink. Applications for the media presentation are as follows : distance learning, online game, collaboration, etc.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.145-152
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• 2012

Due to the large sizes of streaming media, previous delivery techniques are not providing optimal performance. For this purpose, video proxy server is employed for reducing the bandwidth consumption, network congestion, and network traffic. This paper proposes a fast distributed network file system using state transition model in the media streaming system for efficient utilization of video proxy server. The proposed method is composed of three steps: step 1. Training process using state transition model, step 2. base and decision probability generation, and step 3. storing and deletion based on probability. In addition, storage space of video proxy server is divided into each segment area in order to store the segments efficiently and to avoid the fragmentation. The simulation results show that the proposed method performs better than other methods in terms of hit rate and number of deletion. Therefore, the proposed method provides the lowest user start-up latency and the highest bandwidth saving significantly.

• The KIPS Transactions:PartC
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• v.8C no.6
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• pp.765-774
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• 2001

In this paper, we proposed the striping policy for the storage nodes in the Linux-based parallel media stream server. We newly developed a storage clustering architecture, and named it as a system RAID architecture. In this system, many storage cluster nodes are grouped to operate as a single server. This system uses unique striping policy to distribute multimedia files into the parallel storage nodes. If a service request occurs, each storage cluster node transmits striped files concurrently to the clients. This scheme can provide the fair distribution of the preprocessing load in all storage cluster nodes. The feature of this system is a relative striping policy based on the file types, service types, and the number of storage nodes to provide the best service.

• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1766-1777
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• 2000

In multimedia new service on the internet, there are problems such as server overload, network congestion and initial latency. To overcome these problems, we propose a proxy push-caching scheme that stores a portion of continuous media stream or entire stream, and a transmission scheme of NOD continuous media, RTP-RR and RTP-nR to exploit push-caching scheme. With the proposed push-caching scheme, NOD server pushes fixed portion of stream to a proxy when new data is generated, and the cached size of each stream changes dynamically according to the caching utility value of each stream. As a result, the initial latency of client side could be reduced and the amount of data transmitted fro ma proxy server to client could be increased. Moreover, we estimate a caching utility value of each stream using correlation between disk space occupied by the stream and the amount of data stream requested by client. And we applied the caching utility value ot replacement policies. The performance of the proxy push-caching and continuous media transmission schemes proposed were compared with other schemes using simulations. In the simulation, these schemes show better results than other schemes in terms of BHR (Byte Hit Rate), initial latency, the number of replacement and packet loss rate.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.495-502
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• 2004

A rapid growth of the Internet user and rich media content cause an excessive server load and high network traffic, and thus it decreases the quality of service. A solution to this problem is to distribute the content on multiple replicated servers. However, in this circumstance, clients face additional task of selecting the best server to provide proper so${\gamma}$vice which clients request. This paper is intended to propose an adaptive server selection mechanism for a client request based on distance and server load. This will offer a fast and scalable service in response to the increase of massive and realtime multimedia content and contribute to floating a new business model of digital content service.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.647-653
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• 2011

In vessels, various communication systems are now working with different vendor-specific ways, which are apt to cause the inter-operability problems. That, of course, leads to needs of standardization of communication network systems for vessels. The e-navigation system introduced by IMO also takes the standardization process as expected. In this paper, a 4S multiple media communication switching server for seamless communications among existing media for vessels is introduced, and the development of a information exchange software for the sever and its functionality verification results are presented as well.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.10
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• pp.556-568
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• 2003

This paper presents and analyzes the performance of a weighted-window based cache replacement policy for the efficient media caching in streaming media cache servers. The proposed policy makes, for each cached object, use of the reference count, reference time, amount of media delivered to clients and, in particular, the periodic patterns of user requests. Also, by giving weights to the recently referenced media contents, the replacement policy adequately and swiftly reflects the ever-changing characteristics of users preferences. The simulation studies show that the performance of the proposed policy has improved over the conventional policies such as LRU, LFU and SEG - in terms of hit ratio, byte hit ratio, delayed start and cache input.