• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.5
• /
• pp.951-959
• /
• 2001

Video database has the function that stores videos and retrieves the video informations for the service request of users. Therefore, the purpose of the video database is to provide not only an environment both convenient and efficient for retrieving and storing video, but also to serve the requested video informations with rapid startup latency for more users. But, some users of video database as VOD application might tolerate slow startup latency because they would watch video during one hour or two hours. In this paper, we propose the novel policy of the storage system of video database, which serves efficiently the users by considering the classes of the users in video database. The policy admits the random movements of disk heads for urgent user classes but maintains the sequential or restricted movements of disk heads for less-urgent user classes like VOD application in storage system of video database. So, it can not provide only rapid startup latencies for urgent requests but also it can process more service requests in all.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.5
• /
• pp.1172-1181
• /
• 1997

A militimedia data is a data mixed of formatted data like an audio and video. Multimedia data has characteristics that it need large amount of storage,wide network bandwith andreal time responsibolity. Because of these characteristocs, the VOD server and continous media storage server have a disk stripe structure or disk stripe sructure or disk array structure(RAID).In the parallel disk access system,high-speed play-back of continous media using segment interleavung may not ensure Qos pf other cioents because of the concentrated load within some disks. The load concentration of disks is related to both the number of disks in the system and playback rate of contimous media.In this paper. we describe that high-speed playback scheme,which is independent of the number of disk and plyback rate can be achieved by technique of changing the in-teval of access to segnent location.We show the experimental result of this technique in this pater.

• Journal of KIISE:Computer Systems and Theory
• /
• v.28 no.9
• /
• pp.442-460
• /
• 2001

In video-on-demand(VOD) systems it is important to minimize initial latency and memory requirements. The minimization of initial latency enables the system to provide services with short response time, and the minimization of memory requirements enables the system to service more concurrent user requests with the same amount of memory. In VOD systems, since initial latency and memory requirement increase according to the increment of buffer size allocated to user requests, the buffer size allocated to user requests must be minimized. The existing static buffer allocation scheme, however, determines the buffer size based on the assumption that thy system is in fully loaded state. Thus, when the system is in partially loaded state, the scheme allocates user requests unnecessarily large buffers. This paper proposes a dynamics buffer allocation scheme that allocates user requests the minimum buffer size in fully loaded state as well as a partially loaded state. This scheme dynamically determines the buffer size based on the number of user requests in service and the number of user requests arriving while servicing current requests. In addition, through analyses and simulations, this paper validates that the dynamics buffer allocation outperforms the statics buffer allocation in initial latency and the number of concurrent user requests that can be supported. Our simulation results show that, in proportion to the static buffer allocation scheme, the dynamic buffer allocation scheme reduces the average initial latency by 29%~65%, and in a systems having several disks. increases the average number of concurrent user requests by 48%~68%. Our results show that the dynamic buffer allocation scheme significantly improves the performance and reduce the capacity requirements of VOD systems.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1999.04a
• /
• pp.80-87
• /
• 1999

초고속 정보통신망의 구축과 개인용 컴퓨터의 보급이 늘어나면서 인터넷을 비롯한 다양한 형태의 정보 서비스들이 크게 증가하고 있다. 그러한 서비스를 위한 정보들은 대부분 대규모 데이터 전송을 요구하는 음성이나 동영상과 같은 멀티미디어 정보들로 이루어지며, 그들은 전자도서관이나 거대한 정보 저장소에 디지털로 인코딩 되어진 형태로 저장된다. 그런데 사용자들이 원하는 정보가 하나의 서버에만 저자오디는 중앙집중적인 환경에서는 그 서버가 모든 서비스 요구들을 처리해야 하기 때문에 병목 현상이 발생할 수 있고, 네트워크의 과부하로 인하여 양질의 서비스를 제공하기 어려워진다. 본 연구는 멀티미디어 정보중에서도 가장 많은 전송량이 요구되는 VOD 서비스를 효율적으로 지원할 수 있는 환경 구축방안을 찾는 것을 목표로 한다. 이를 위하여 비디오 정보들을 다수의 서버들에 분산 저장하고, 서버의 위치와 정보의 배치 방법에 따른 서비스 시간과 throughput을 시뮬레이션으로 분석하고, 각각의 경우에 대한 비용을 추정하여 가격대성능비 측면에서 가장 효율적인 방법을 제안하였다.

• Proceedings of the IEEK Conference
• /
• 2003.07d
• /
• pp.1661-1664
• /
• 2003

The transcoding is a method which converts a multimedia stream to an adaptive format, such as frame rate and resolution, that can be played in the mobile devices. Due to the heavy consumption of CPU power for transcoding, the server in charge cannot supply all streams requested from clients if it is already occupied by several streams. The load balancing among proxies is a common approach for solving such problem. In addition to collaborative works for load balancing, the mobility must be taken into account in the mobile environments. Thus, the wired-network based algorithm is not suitable for the streams service in the mobile environments. In this paper, we propose an alternative scheme for cooperative proxy architecture that considers the case in which mobile devices are moving over other zones.

• Journal of Korea Multimedia Society
• /
• v.6 no.7
• /
• pp.1209-1218
• /
• 2003

To guarantee client buffer stabilization and visual quality, the VOD service that provides real time video titles on requirements of numerous users, needs a mechanism which transfers frames with dropping or skipping algorithm by network condition. In this paper, we show an algorithm that transfers withdrawed skipped MPEG frames(I, P, B frame) from disk to client dependent on network load. Moreover, we verify through a simulation that adaptive dealing on network load can reduce the network load and stabilize client receiving buffer.

• Journal of the Korea Computer Industry Society
• /
• v.4 no.10
• /
• pp.741-750
• /
• 2003

$MTP^{TM}$ guarantees high bandwidth that is necessary to tansmit high qualify full motion video data effectively. In other hand TCP/IP which is used for information search does not guarentee high bandwidth as that in $MTP^{TM}$. Therefore VOD service system that searches information manged by DBMS and transmits required full motion video data should control different kinds of protocol simultaneously. This paper describes the configuration of VODB system that has solved these problems.

• Korean journal of communication and information
• /
• v.34
• /
• pp.98-131
• /
• 2006

The objective of this study is to review diverse determinants of windowing in Korean drama such as rating, theme, type of drama, quantity of newsbreak and independent production. The after-market will be overseas market, domestic cable TV and emerging two revenue sources such as VOD and DVD. Korean dramas aired on free TV between 2000 and 2004 will be analysed by chi-square.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2000.11a
• /
• pp.345-348
• /
• 2000

요즘 PC를 이용한 여러 가지 사업 아이템들이 상품화되어 쏠아져 나오고 있다. 대표적으로 PC방을 비롯해 가정에서도 고속 인터넷이 가능해지면서 게임뿐만이 아니라 전반적인 생활 자체가 컴퓨터를 통해 이루어져 가고 있다고 해도 과언이 아니다. 흔히 볼 수 있는 노래방 또한 그 예외가 된 수 없다. 현재 노래방에서의 한계점은 신곡이 추가될 때마다 대부분 팁 자체를 교환하거나 추가해줘야 하고 TV 브라운관에 보이는 영상 또한 비디오를 통해 따로 상영해 주어야 한다. 본 논문에서는 PC로 클라이언트-서버 모델을 이용해 노래방 시스템을 구성하여 기존 노래방 시스템의 단점을 극복하고 나아가서 여러 가지 부가 서비스를 지원해 줄 수 있는 인터넷 노래방 시스템의 구현에 대해서 기술한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.05a
• /
• pp.741-742
• /
• 2013

Passive optical networks (PONs) are the emerging solution for access networks since PONs provide high bandwidth. TDM ((time-division multiplexing) PON cannot support sufficient bandwidth for new broadband services such as UHD (ultra high-definition) IP TV, and VOD (video on demand). The solution is TWDM PON which is a mixture of WDM (wavelength-division multiplexing) and TDM. This paper proposes a new MAC (media access control) protocol for TWDM PON.