Yuhyeon Bak

The PT-2 caching algorithm in the transcoding proxy cluster to facilitate adaptive content delivery

With the advent of wireless network devices, clients such as PDAs and mobiles have become heterogeneous in terms of their capabilities. For the purpose of maintaining different categories of clients, transcoding has emerged as a major field in adaptive multimedia delivery. However, little work has been performed in the area of caching transcoded streaming media in a cluster environment. We therefore propose a new partial caching algorithm for improving cache utilization and adapting heterogeneous content delivery to reduce startup latency.

Design and implementation of the script-based service deployment solution

This paper provides a general overview of the script-based service deployment solution for Unix environments. Our solution requires password-less or pass-phrase-less SSH configuration for basic functionality. The service deployment solution overcomes limitations of Nixes, while maintaining simplicity and ease of use

EXT3NS: Multimedia File System Supporting Network/Storage Card

The EXT3NS is a file system based on a special HIW device, called NS card for multimedia data. In general, normal computer has high level of CPU utilization for networking operations with gigabit level and several copy operations. Therefore, we have developed the NS card to alleviate this overhead. EXT3NS provides the standard APIs to read and write files in storage unit of NS card. The performance measurements on our system show obvious performance improvements. Especially, the system shows much less servers CPU utilization and less fluctuation of client bitrate, hence more reliable streaming service is possible.

On Multiple Description Streaming with Cluster-based Server

The cluster system with shared-nothing storage cannot escape from the problem of skewed request toward specific contents. This paper, therefore, suggests streaming method using MDC (multiple description coding) instead of using single original content; this method is able to cope with skewed request in shared-nothing storage server as well as to continue to provide services in case of the system failure. Also, the system can support adaptive streaming service according to user player type, network status, the load of server, and client

The design and implementation of asset management system on the NGIS

We have developed the next generation Internet server (NGIS) which has network-storage (NS) Cards for streaming service. The NGIS system provides assets of various types to support streaming service and has NS cards with a powerful network function. The NGIS system offers streaming service for assets of various types, such as MPEG 1 files, MPEG 2 files and MPEG 4 files. In this paper, we propose the method of installing assets, such as MPEG 1 files, MPEG 2 files and MPEG 4 files, to support to streaming service in the NGIS system. If the type of multimedia data is MPEG 1 or 2, we propose the method of installing assets, which makes fast forward (FF) files and fast rewind (FR) files in real-time in order to support a FF service and a FR service, and suggest another method which makes a FF file and a FR file off-line and installs the FF file and the FR file when system of installing assets begins. In this paper, also, we propose contents management system (CMS) calling asset installer automatically to install assets when the assets are at a certain place.

The SZIT based-mapping method for on-line adding disks in software RAID

According as the users can connect to remote hosts at anytime by using internet, the demand of non-stop system is increased. Also, the research about on-line adding/deleting disks and hosts are progressed. This paper suggests that the method of reducing additional operation when we add disks to the stripping system. That method can fast mapping like equation based mapping method because of using so-called SZIT(Striping Zone Information Table) and equations. And that method can reduce the relocation overhead in striping system at adding disks.