• Journal of Korea Multimedia Society
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• v.7 no.8
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• pp.1058-1065
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• 2004

Embedded system is widely used in various applications from simple monitor to a set-top box with CPU, memory and hard disk drives. Specially, embedded OS is ported in moveable or small machinery since it ordinarily transmits multimedia data. In this paper, we propose Null copy scheme on the embedded linux system for multimedia service, which can reduce memory copy overhead from user address space to kernel one, and vice versa. Since embedded system for networked multimedia service has low level computing power as well as memory, the Null copy scheme can provide more improved QoS. Our image transmission experiment results on embedded linux target board(CPU utilization an Deadline miss rates) installed a web camera have shown that the proposed scheme can increase fast response and lower CPU overhead.

• ETRI Journal
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• v.32 no.5
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• pp.657-664
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• 2010

Many embedded multimedia systems employ special hardware blocks to co-process with the main processor. Even though an efficient handling of such hardware blocks is critical on the overall performance of real-time multimedia systems, traditional real-time scheduling techniques cannot afford to guarantee a high quality of multimedia playbacks with neither delay nor jerking. This paper presents a hardware-aware rate monotonic scheduling (HA-RMS) algorithm to manage hardware tasks efficiently and handle special hardware blocks in the embedded multimedia system. The HA-RMS prioritizes the hardware tasks over software tasks not only to increase the hardware utilization of the system but also to reduce the output jitter of multimedia applications, which results in reducing the overall response time.

• Journal of Information Technology Applications and Management
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• v.12 no.1
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• pp.125-140
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• 2005

Nowadays, we have many embedded systems which store and process multimedia data. For multimedia systems using hard disks as storage media such as DVR, existing file systems are not the right choice to store multimedia data in terms of cost. performance and reliability. In this study we designed a reliable file system with very high performance for embedded multimedia applications. The proposed file system runs with quite simple disk layout to reduce time to initialize and to recover after power failures, uses a large data block to speed up the sequential accesses, incorporates a time-based indexing scheme to improve the time-based random accesses and boosts reliability by backing up the important meta data on a small NVRAM. We implemented the file system on a Linux-based DVR and verified the performance by comparing with existing file systems.

• Korea Multimedia Society
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• v.7 no.4
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• pp.30-39
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• 2003

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.770-774
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• 2002

Recently, most of the embedded system have the function of multimedia information processing and network connecting. This make the overall system more complicated and need a new approach. Moreover the embedded system must be real-time system, which are different with Linux is constructed and the kernel is redesigned on the strong-arm board in order to make the real-time embedded web-server system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.71-80
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• 2004

This paper describes embedded processor architecture design which is applicable to multimedia in mobile platform The main description is based on basic processor architecture and consideration about energy efficiency when used in mobile platform To design processor data path architecture (pipeline, branch prediction, multiple issue superscalar, function unit number) which is optimal to multimedia application and cache hierarchy and its structure, we have nut the simulation with variant architecture using MPEG4 test bench as multimedia application. We analyzed energy efficiency of architecture to check if it is applicable to mobile platform and decide basic processor architecture based on analysis result. The suggested basic processor architecture not only can be applied to mobile platform but also can be applied to basic processor architecture of configurable processor which is designed through automatic design environment.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.6
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• pp.460-471
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• 2004

Since the RTP is suitable for real-time data transmission in multimedia services like VoD, AoD, and VoIP, it has been adopted as a real-time transport protocol by RTSP, H.323, and SIP. Even though the RTP protocol stack for embedded systems has been in great need for efficient support of multimedia services, such a stack has not been developed yet. In this paper, we explain embeddedRTP which supports the RTP protocol stack at the kernel level so that it is suitable for embedded systems. Since embeddedRTP is designed to reside in the UBP module, existing applications which rely ell TCP/IP services can proceed the same as before, while applications which rely on the RTP protocol stack can request HTP services through embeddedRTp API. EmbeddedRTP stores transmitted RTP packets into per session packet buffer, using the packet's port number and multimedia session information. Communications between applications and embeddedRTP is performed through system calls and signal mechanisms. Additionally, embeddedRTP API makes it possible to develop applications more conveniently. Our performance test shows that packet-processing speed of embeddedRTP is about 7.5 times faster than that oi VCL RTP for multimedia streaming services on PDA in spite that its object code size is reduced about by 58% with respect to UCL RTP's.

• Journal of the Korea Society of Computer and Information
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• v.12 no.2 s.46
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• pp.9-19
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• 2007

In recent, development of wireless internet technology gradually has increased multimedia application in mobile device. Specially, application of grand capacity multimedia contents has increased in mobile environment gradually. MPEG-7 can search multimedia data using various type. But in restricted grand capacity of multimedia, MPEG-7 is used to be limited in desktop computer system mostly. Therefore, management of grand capacity multimedia data has become very important researching topic in mobile environment, and so embedded DBMS based on MPEG-7 for multimedia data management in client-server environment is needed. The system supports restricted hardware resource for multimedia application in mobile device. In this paper, we propose a method for MPEG-7 data clustering that included MPEG-7 data property. On the base of the clustering result, we also develop the embedded multimedia database management system based on MPEG-7 scheme(EMDS:MPEG-7 Scheme Based Embedded Multimedia Database Management System) in mobile device such as PDA.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11b
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• pp.1006-1009
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• 2003

In a motion estimation method for use in encoding a moving picture, a full-pixel motion vector is estimated by stochastically sampling a pixel to be processed in a predetermined-sized block of a previous frame or a next frame as a reference frame for each of a plurality of equal-sized blocks in a current frame. Then, a half-pixel motion vector is estimated based on the full-pixel motion vector. Accordingly, both the calculation amount and the calculation time required for the motion estimation are effectively reduced. Further, it can be prevented that the hardware becomes complicated. .

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.482-486
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• 2003

본 논문에서는 PC 또는 mobile phone에서 web server로 접속하여 모형 자동차를 무선 환경에서 원격으로 제어하는 기능을 Linux 기반의 embedded system을 이용하여 구현하였다. 본 system에는 IIS(Internet Information Service) 와 LODEK embedded system 및 ASP(Active Server Pages) 가 사용 되었으며 motor 제어 회로가 구현되었다.