• Journal of Korea Multimedia Society
• /
• v.13 no.9
• /
• pp.1272-1284
• /
• 2010

As the mobile computers are becoming powerful and are used like general-purpose computers, operating systems for mobile computers also require swap system functionality that utilizes main memory efficiently. Flash memory is widely used as storage device for mobile computers but current linux swap system does not consider flash memory. Swap system is tightly related with process execution since it stores the contents of process in execution. By taking advantage of this characteristics, in this paper, we study a new linux swap system called PASS(Process-Aware Swap System), which allocates the different flash memory blocks to each process. Trace-driven experimental results show that PASS outperforms existing linux swap system with existing garbage collection schemes in terms of garbage collection cost.

• The KIPS Transactions:PartD
• /
• v.14D no.6
• /
• pp.615-622
• /
• 2007

Recently, users who want to be provided motile devices, such as PDP, PMP, and IPTV connected wireless internet, with multimedia contents are increasing due to an influence of multimedia contents. In the paper, we propose an efficient database design method for managing mobile multimedia services on home network systems. For this, we build relations using attributes required while providing multimedia services, and then design a database. Specially, we propose a database design method based on normalization theory to eliminate redundancies and update anomalies caused by a non trivial multi valued dependency in relations. In the experiments, we compare and analyze occurrence frequencies of data redundancies and update anomalies through query executions on the relation decomposed into normal forms. The results reveal that our database design is failrly effective.

• Journal of Digital Contents Society
• /
• v.7 no.2
• /
• pp.117-124
• /
• 2006

In ubiquitous computing environment, a user can access their personalized services at anytime, anywhere, through any possible mobile or fixed terminals in a secure way. If the user wants to move to a different location, they need to stop the video play at the current location and makes a new request at the new location. As well, the user needs to manually search for the last frame to be seen at the previous location. In this paper, we proposed an implementation of multimedia contents streaming service mobility by user's location tracking. User can play video seamlessly while moving from one machine to another along the user's moving trail.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.643-646
• /
• 2005

In this paper, we present a service model which serves multimedia contents to end consumer(End-user) that have various mobile communication terminals under a communication & broadcasting converged environment that broadcasting and communication networks are linked. A main feature of this service model is that it has a distribution structure that deliver to end consumer via adaptation of content from production of contents offering End to End (E2E) media QoS and personalized contents consumption. The proposed service model may be used as a reference model for distribution of multimedia content in communication & broadcasting converged environment in the future.

• Journal of Broadcast Engineering
• /
• v.11 no.3 s.32
• /
• pp.363-378
• /
• 2006

The Digital Multimedia Broadcasting(DMB) system is developed to offer high quality audio-visual multimedia contents to the mobile environment. The system adopts MPEG-4 standard for the main video, audio and other media format. It also adopts the MPEG-4 scene description for interactive multimedia contents. The animated and interactive contents can be actualized by BIFS(Binary Format for Scene), the binary format for scene description that refers to the spatio-temporal specifications and behaviors of the individual objects. As more interactive contents are, the scene description is also needed more high bitrate. However, the bandwidth for allocating meta data such as scene description is restrictive in mobile environment. On one hand, the DMB terminal starts demultiplexing content and decodes individual media by its own decoder. After decoding each media, rendering module presents each media stream according to the scene description. Thus the BIFS stream corresponding to the scene description should be decoded and parsed in advance of presenting media data. With these reason, the transmission delay of BIFS stream causes the delay of whole audio-visual scene presentation although the audio or video streams are encoded in very low bitrate. This paper presents the effective optimization technique for adapting BIFS stream into expected MPEG-2 TS bitrate without any bandwidth waste and avoiding the transmission delay of the initial scene description for interactive DMB contents.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2002.11b
• /
• pp.617-621
• /
• 2002

현재 잘 갖추어진 정보통신 인프라에서 이동통신사들이 제공하는 서비스들이 각기 다른 무선 마크업 언어를 사용하고 있어 하나의 컨텐츠를 제공하기 위해서는 각 이동통신사별로 별도의 추가 개발이 이루어져야 하는 등 서비스 발전에 장애 요인이 존재한다. 본 연구에서는 이러한 국내외 무선 인터넷의 현실을 고려하여 무선 인터넷 컨텐츠의 생산성 향상 또는 서비스의 질적 향상을 위하여 유무선 인터넷 컨텐츠들을 이동 단말기들에 적합하도록 변환 작성하여 전송해주는 프럭시(proxy)를 개발하였다. 본 연구의 특징은 metaXML로 정의된 중간 언어를 채택하여 서로 다른 마크업 언어로 작성된 컨텐츠들을 효과적으로 변환할 수 있다.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2003.11b
• /
• pp.1031-1034
• /
• 2003

향후 무선인터넷 망이 완전히 개방되면 다양한 포털, 컨텐츠 사업자가 등장할 것이다. 이는 사용자에게는 다양한 서비스를 받을 수 있는 장점이 있지만 현재 휴대폰에서의 모바일 인터넷 컨텐츠 탐색 시 발생하는 사용성 문자를 한층 더 증대 시킬 것으로 예상된다. 기존의 연구들은 단일 포털 업체만을 대상으로 연구를 하였기 때문에 여러 포털 업체에서 제공하고 있는 컨텐츠들을 적절히 탐색할 수 있는 기법에 대해서는 아직 연구가 부족하다. 본 논문에서는 시멘틱 웹 구현 기법 중 하나인 토픽맵을 이용하여 효율적으로 모바일 인터넷 컨텐츠를 탐색하고 관리할 수 있는 기법을 제안한다.

• Korea Multimedia Society
• /
• v.5 no.1
• /
• pp.68-75
• /
• 2001

컴퓨터 기술과 네트워크 기술의 결합은 새로운 기술의 가능성을 제시하였고, 다양한 미디어의 융합을 통하여 새로운 멀티미디어 세상이 전개되기 시작했다. 쇼핑, 강의, 진료, 회의 등이 가상 세계에서 가능하게 되었으며 다양한 음악, 영화, 게임 등을 컴퓨터 네트워크를 통하여 실시간으로 즐길 수 있게 되었다. 즉, 인터넷을 통하여 텍스트, 이미지, 사운드, 동영상 등을 기반으로 하는 멀티미디어 컨텐츠를 누구나 쉽게 얻을 수 있고 이를 다시 복제, 배포할 수 있는 환경이 되었다.(중략)

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2010.07a
• /
• pp.360-363
• /
• 2010

Streaming Technology can support the real-time playback without downloading and storing multimedia data in local HDD. So, client browser or plug-in can represent multimedia data before the end of file transmission using streaming technology. Recently, the demand for efficient real-time playback and transmission of large amounts of multimedia data is growing rapidly. But most users' connections over network are not fast and stable enough to download large chunks of multimedia data. In this paper, we propose an intelligent IP streaming system based on personalized media service. The proposed IP streaming system enables users to get an intelligent recommendation of multimedia contents based on the user preference information stored on the streaming server or the home media server. The supposed intelligent IP streaming system consists of Server Metadata Agent, Pumping Server, Contents Storage Server, Client Metadata Agent and Streaming Player. And in order to implement the personalized media service, the user information, user preference information and client device information are managed under database concept. Moreover, users are assured of seamless access of streamed content event if they switch to another client device by implementing streaming system based on user identification and device information. We evaluate our approach with manufacturing home server system and simulation results.

• Journal of Advanced Navigation Technology
• /
• v.17 no.1
• /
• pp.56-62
• /
• 2013

Recently with smart phones and tablets, next generation mobile communication systems have supported various multimedia contents services. Thus, multimedia communication systems have been gradually increased compared to voice communication systems. Since the growth of multimedia services has increased users' duration on systems and decreased systems' effectiveness on power, a study on effective usage of power needs to be researched. Furthermore, radio shadow areas under heavy urban environments have generated unnecessary power consumption which reduces the usage duration of power on next generation mobile communication systems. This paper has reviewed the communication network architecture on next generation mobile communication systems and the unnecessary power consumption in radio shadow areas. This paper has also proposed the method of the effective power usage and analyzed the effective power usage on next generation mobile communication systems with simulation.