• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.6
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• pp.93-103
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• 2009

Recently, there is an increase in demand of real-time multimedia service in the WLAN environment, with a commercialization of IEEE 802.11n standard. However, the 802.1x authentication protocol is too slow to provide seamless real-time multimedia service, which defined in an IEEE 802.11i security standard. In this paper, a Ticket-based authentication mechanism in the CAPWAP(Control And Provisioning Wireless Access Point) architecture is introduced to support for the fast handoff.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.51-56
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• 2014

Thesedays, there are many smart device applications developed, especially on the using various sensors included in the smart device. Smart devices have several sensors which are camera, GPS, mike, and communication module for collecting ubiquitous environment, and many applications are developed by using such sensors. In this paper, we developed the multimedia stream architecture and examined the smart device applications based on open source with front and back-end server clouds for developing the conceptual architecture. Also, we examined the back-end distributed servers, realtime multimedia stream transferring, multi-media store, and media relay for other server and smart devices. We test the examined architecture on the real target environment to collect the SIP initial setup time, media stream delay, and end-to-end play time. The test results show that there have good network operation environment to provide realtime multimedia services, and we need to improve the end-to-end play time by minimizing the initial setup time.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.38-41
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• 2014

Due to the diversity of device performances and the possibility of providing multimedia service through many networks, media consumption environment has been changed in various ways. In recent, mobile services and broadcasting services started to provided through IP network. According to this flow changes, there was great demand for various multimedia services through heterogenous networks. To solve this problem, MMT was suggested as a standard of multimedia transport which replaces MPEG-2 TS(Transport Stream) which is used for HD(High Definition) transport. MMT can be provided various broadcasting based on IP through terrestrial, satellite, cable broadcasting networks, and also deliver multimedia through many networks at the same time. MMT was risen as a method of servicing UHD broadcasting. In this paper, we present an implementation of service architecture for hierarchical UHD broadcasting over heterogenous networks using MMT.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.7
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• pp.305-317
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• 2008

As a mobile computing environment is rapidly changing, increasing user demand for multimedia-over-wireless capabilities on embedded processors places constraints on performance, power, and sire. In this regard, this paper proposes color media instructions (CMI) for single instruction, multiple data (SIMD) parallel processors to meet the computational requirements and cost goals. While existing multimedia extensions store and process 48-bit pixels in a 32-bit register, CMI, which considers that color components are perceptually less significant, supports parallel operations on two-packed compressed 16-bit YCbCr (6 bit Y and 5 bits Cb, Cr) data in a 32-bit datapath processor. This provides greater concurrency and efficiency for YCbCr data processing. Moreover, the ability to reduce data format size reduces system cost. The reduction in data bandwidth also simplifies system design. Experimental results on a representative SIMD parallel processor architecture show that CMI achieves an average speedup of 6.3x over the baseline SIMD parallel processor performance. This is in contrast to MMX (a representative Intel's multimedia extensions), which achieves an average speedup of only 3.7x over the same baseline SIMD architecture. CMI also outperforms MMX in both area efficiency (a 52% increase versus a 13% increase) and energy efficiency (a 50% increase versus an 11% increase). CMI improves the performance and efficiency with a mere 3% increase in the system area and a 5% increase in the system power, while MMX requires a 14% increase in the system area and a 16% increase in the system power.

• Information and Communications Magazine
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• v.29 no.9
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• pp.56-62
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• 2012

초고속 인터넷, 다양한 통신 기기, 신규 인터넷 애플리케이션 등의 확산으로 인터넷 상의 콘텐츠 트래픽 규모가 급격하게 증가하고 있다. 비디오와 같은 대용량 멀티미디어 콘텐츠 트래픽이 전체 트래픽에서 차지하는 비중은 날로 증가하여, 2014년에는 전체 인터넷 트래픽 중 90% 이상을 차지할 것이라고 예측되기도 한다. 따라서 트래픽의 대부분을 차지하는 콘텐츠 중심으로 네트워크 아키텍처를 혁신할 필요성이 대두되고 있다. 본 논문은 최근 급증하는 콘텐츠 서비스의 송수신 특성에 적합한 네트워크 아키텍처에 대한 학계와 산업체의 연구동향과 콘텐츠 네트워킹 관련 기술의 국제 표준화 동향을 고찰하고, 향후 실제 적용을 위한 이슈를 분석한다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.769-772
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• 2006

지식정보화의 사회적 발전에 따라 IT기술도 장소와 공간에 제약 받지 않는 이동성, 휴대성이 강조되고 있다. 이는 유비쿼터스 사회로의 급격한 진입이라는 시대적 상황과 맞물려 유비쿼터스 컴퓨팅 환경에 적합한 컴퓨팅 디바이스의 등장이 요구되고 있다. 본 논문에서는 다양한 포터블기기(PMP, UMPC, MP3, 게임기)들의 기능과 콘텐츠를 조사, 분석하여 차세대 포터블 멀티미디어 시스템에서 요구되는 기능을 도출하였으며 또한 이를 기반으로 모듈화 된 포터블 멀티미디어 시스템의 구조를 설계했다. 본 연구의 결과는 점차 성숙해가고 있는 포터블 멀티미디어 시스템 산업의 하드웨어적 표준을 제시함으로써 효율적인 개발 방안을 모색할 수 있을 것으로 기대된다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.5
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• pp.465-471
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• 2016

An IPTV has emerged as a widespread system when a realtime network and broadcasting system have progressed. Interestingly, it can also be organized with IPTV STBs and FC-AL for a high-quality TV content-sharing architecture. It is, however, not easy to configure a large community network with the FC-AL since it only has a 7-bit address space with supporting up to 127 users in the FC-AL single loop. We, therefore, propose an extendible FC-AL-based IPTV network architecture using a FC switch device. In this article, our suggested architecture shows a superb startup delay, such as less than 20msec. In addition, it demonstrates outstanding extendibility, such that the number of accomodable users increases almost linearly according to adding loops. Lastly, it reveals exceptional time-shifting hours, i. e., which supports more than 140 hours with 1000 users.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.78-80
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• 1999

마이크로 커널 구조는 필수 불가결한 커널 기능만을 가지게 되며, 운영체제의 기능성은 서버로 동작하게 된다. 따라서 모노리틱 운영체제에 비해서 커널 기능의 확장 및 개발이 용이하다는 장점을 가지게 된다. 본 연구에서는 기존에 제시된 마이크로 커널의 접근방식에서 추가적으로 멀티미디어를 지원할 수 있는 멀티미디어 마이크로 커널(M3K)을 구현하고 있다. 특히 M3K는 멀티미디어의 실시간 특성 및 기능을 제공할 수 있는 구조로서 컴포넌트에 기반한 커널 프레임워크를 사용하고 있다. 본 논문은 M3K 마이크로 커널을 구현함에 있어서 커널 구조 자체를 컴포넌트화시켜 필요한 기능만을 선택적으로 결합해서 사용할 수 있는 방법을 제시하고 있으며, 현재 동작중인 쓰레드 컴포넌트의 아키텍처 위주로 설명한다.

• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.1076-1087
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• 2010

Together with a new advent of embedded processor developed to support specific application area and it evolution, a new research of software development to support the embedded processor and its commercial challenge has been revitalized. Retargetability is typically achieved by providing target machine information, ADL, as input. The ADLs are used to specify processor and memory architectures and generate software toolkit including compiler, simulator, assembler, profiler, and debugger. The EXPRESSION ADL follows a mixed level approach-it can capture both the structure and behavior supporting a natural specification of the programmable architectures consisting of processor cores, coprocessors, and memories. And it was originally designed to capture processor/memory architectures and generate software toolkit to enable compiler-in-the-loop exploration of SoC architecture. In this paper, we designed the class-based ADL based on the EXPRESSION ADL to promote the write-ability, extensibility and verified the validation of grammar. For this works, we defined 6 core classes and generated the EXPRESSION's compiler and simulator through the MIPS R4000 description.

• The KIPS Transactions:PartA
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• v.18A no.3
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• pp.99-108
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• 2011

Processor technology is currently continued to parallel processing techniques, not by only increasing clock frequency of a single processor due to the high technology cost and power consumption. In this paper, a SIMD (Single Instruction Multiple Data) based parallel processor is introduced that efficiently processes massive data inherent in multimedia. In addition, this paper proposes pixel subword parallel processing instructions for the SIMD parallel processor architecture that efficiently operate on the image and video pixels. The proposed pixel subword parallel processing instructions store and process four 8-bit pixels on the partitioned four 12-bit registers in a 48-bit datapath architecture. This solves the overflow problem inherent in existing multimedia extensions and reduces the use of many packing/unpacking instructions. Experimental results using the same SIMD-based parallel processor architecture indicate that the proposed pixel subword parallel processing instructions achieve a speedup of $2.3{\times}$ over the baseline SIMD array performance. This is in contrast to MMX-type instructions (a representative Intel multimedia extension), which achieve a speedup of only $1.4{\times}$ over the same baseline SIMD array performance. In addition, the proposed instructions achieve $2.5{\times}$ better energy efficiency than the baseline program, while MMX-type instructions achieve only $1.8{\times}$ better energy efficiency than the baseline program.