• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.197-200
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• 2009

Since various type of wireless/mobile network likes WLAN, WIBRO, HSDPA were come to us, technology providing high quality multimedia service while user move are actively researched such as MIH (Media Independent Handover) proposed by IEEE for interworking between heterogeneous network and CMIP (Client Mobile IP), PMIP (Proxy Mobile IP) for mobility. Despite the technology about interworking and handover between heterogeneous network are actively researched, handover decision method need to be researched. In this paper we suggest a simple and effective handover method for high quality multimedia service in real wireless environment. For this, we use MIH+CMIP platform for target multimedia service to make handover decision rule in WIBRO and HSDPA networks. After apply this rule, we verified effectiveness of handover decision method through real test.

• Korea Multimedia Society
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• v.5 no.2
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• pp.62-71
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• 2001

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.378-381
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• 2011

These days rapid improvement in Mobile phones and their multimedia limits made them powerful enough to manage complicated tasks. Image processing related support for mobile devices is extremely comprehensive in wireless telemedicine. A basic challenge is how to get best quality of image with the limited screen size and resources of mobile phones. This paper deals with image processing features (capturing rendering and zooming in and out) of Mobile Media API and Advanced Multimedia Supplements (MMAPI and AMS) developed for Mobile Java Platform and customized algorithm is designed to keep all image task cost efficient by using minimum device resources and memory. This scenario is driven by the need for evaluation of a distant patient that cannot be moved to the expert.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.477-480
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• 2001

무선 정보 환경의 변화에 따라 다양한 정보에 대한 풍족함이 요구되면서 양질의 정보를 정확하고 빠르게 선별하여 획득하는 기술이 점점 중요하게 되었으며, 이러한 페러다임의 요구에 Mobile Agent는 중요한 연구가 된다. 본 논문에서는 Mobile Agent가 가져야 할 보안적 요구사항 중 신뢰할 수 있는 Proxy Server를 이용한 인증을 통해 Sever와 Mobile Agent간의 안전한 통신 방법을 제시하며, Server나 Mobile Agent의 부정이 발견되었을 경우 DSS(Digital Signature Standard) 방식의 서명값을 이용하여 이를 증명함으로써 보다 안전하고 효율적인 상호인증 방식을 제안하였다.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.61-63
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• 2004

The procurement of a mobile microwave scatterometer platform involved the consideration to ensure a mobile platform and equipment selected full-filled technical requirement and safety standard in Malaysia. Designing, and modification works involved engineering methodology in determining and selecting a suitable hydraulic telescopic boom that suit a selected mobile platform available locally. The mobile platform is a delivery system for microwave remote sensing microwave scatterometer and other accessories to any locations in Malaysia. Total loading to be carried by the mobile platform is 4500 kg and its overall weight must be 16,000 kg as recommended by hydraulic telescopic boom manufacturers. The telescopic boom will elevate microwave scatterometer system including the antenna to a maximum height of 27 m, and can also be rotated through $3600^{\circ}$. A mechanism is incorporated in the system to enable tracking or monitoring angular movement of the hydraulic telescopic boom when positioned towards predetermined target.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1245-1253
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• 2009

Since 2000, the demand for multimedia content consumption has been continuously increasing. The research and standardization for the mobile broadcast service has been done to deliver multimedia contents to the huge number of users with the minimum cost. A few commercial services started after the related standards were released. We call this mobile broadcast service the 1st generation service. Now, many experts are researching and developing the technologies for 3Screens(TV, PC, and Mobile) Services that an user can enjoy multimedia contents at every place with the various networks and devices. To enable this service, two main technical areas exist. The first is a core network technology that can support the various access network and the second is a common application layer technology. To resolve these technical areas, we propose IMS(IP Multimedia Subsystem) based OMA BCAST(Open Mobile Alliance Mobile Broadcast Service Enabler Suite) as the technical solution for 3 Screen Services in the paper. In addition, we propose application layer multicast that is enable to implement IMS based OMA BCAST to the existing network with the minimum cost. Finally, we show how we can save the implementation cost of IMS based OMA BCAST with the simulation results.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.491-495
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• 2005

Due to the miniaturization and the network supporting functions of home appliances, there is growing need for mobile environment home network system which provides flexibility, mobility and convenience to users. However in home, there are obstacles which make shaded areas and only static and restricted services are available for the existing mobile environment home network system. In this paper, we proposed the mobile environment home network system using Home Robot in order to solve the problem of existing mobile environment home network system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.766-774
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• 2004

The future mobile communication system can support not only voice but also multimedia applications such as data, image and video. It requires greater resources than the voice-oriented mobile system. Efficient resource reservation and hand-over schemes are necessary to maintain the same QoS of transmitted multimedia traffic because the QoS may be defected by some delay and information loss during hand-over. This paper proposes a resource reservation scheme to accommodate multimedia traffics in mobile multimedia networks. In our scheme the position of mobile is estimated in two steps, that is, sector estimation and zone estimation. With this position information, the moving direction is determined. According to simulation results, our scheme provides a better performance than conventional methods.

• ETRI Journal
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• v.24 no.3
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• pp.247-250
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• 2002

In this paper, we propose three symbol syn-chronization schemes for Orthogonal Frequency Division Multiplex (OFDM) systems. The cyclic extension preceding OFDM symbols is of decisive importance for these schemes. The first scheme uses the phase-differential coding of the received OFDM signal. The second and the third schemes use the length of the received OFDM signal. All three schemes make symbol synchronization possible, even though there is a frequency off-set in the system. Simulation results show that these schemes can be used to synchronize an OFDM system over AWGN and multi-path fading channels.

• Journal of Internet Computing and Services
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• v.4 no.4
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• pp.65-74
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• 2003

Recently, It is required that multimedia data display on not only PC but also the Mobile device such as cellar phone, PDA. Mobile divieces has not sufficient of storage space or main memory and has slow network speed. So we can't process the multimedia data with the existing way on PC. This paper presents various methods for MultimediaPresentation which are able to display on the mobile device with the low-bandwidth and small storage. There Is an analysis that Is playable on the mobile device using presentation area devision method and replayable analysis method. If the display of multimedia presentation is impossible from this analysis, to apply prefetch techniques a using EPOB apoint and as User QoS of multimedia data through prefetch techniques have keep, do so that playable. Then, it is proposed to playable smooth multimedia presentation as that each of the presentations through prefetch Scheduling techniques point and quantity of data which are prefetch.