• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.663-665
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• 2004

Ethernet-based passive optical network(EPON) technology is being considered as a promising solution for next-generation broadband access network. It must have the property of high efficiency, low cost, and support quality of service(QoS). A major feature for this new architecture is the use of a shared transmission media between all connected optical network unit(ONU). Hence, medium access control(MAC) arbitration mechanisms are essential for the successful implementation of EPON. In this paper we propose a simple dynamic bandwidth allocation(DBA) algorithm that improves the performance of network and supports IP-based multimedia applications with the bursty data traffic. In addition, we introduce analytic models of proposed algorithms and prove the system based on our algorithm to be asymptotically stable. Simulation results show the new DBA algorithm provides high bandwidth efficiency and low queueing delay of ONU in EPON.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1661-1664
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• 2003

The transcoding is a method which converts a multimedia stream to an adaptive format, such as frame rate and resolution, that can be played in the mobile devices. Due to the heavy consumption of CPU power for transcoding, the server in charge cannot supply all streams requested from clients if it is already occupied by several streams. The load balancing among proxies is a common approach for solving such problem. In addition to collaborative works for load balancing, the mobility must be taken into account in the mobile environments. Thus, the wired-network based algorithm is not suitable for the streams service in the mobile environments. In this paper, we propose an alternative scheme for cooperative proxy architecture that considers the case in which mobile devices are moving over other zones.

• Journal of Korea Game Society
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• v.10 no.5
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• pp.95-102
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• 2010

This paper proposes a parallel algorithm of the flocking behaviors using GPU. To do this, we used CUDA as the parallel processing architecture of GPU and then analyzed its characteristics and constraints. Based on them, the paper improved the performance by parallelizing to find the neighbors for an agent which requires the largest cost in the flocking behaviors. We implemented the proposed algorithm on GTX 285 GPU and compared experimentally its performance with the original spatial partitioning method. The results of the comparison showed that the proposed algorithm outperformed the original method up to 9 times with respect to the execution time.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.413-416
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• 2004

네트워크 기술의 발달과 컴퓨터 성능의 향상으로 영화, 음악, 게임, 도서 등과 같은 다양한 형태의 디지털 콘텐츠 산업이 발전하였다. 그러나 P2P 기술을 이용한 파일 공유 서비스는 디지털 콘텐츠의 불법적 사용을 부추기고 있다. 이러한 디지털 콘텐츠 불법 복제와 무단 배포는 창작자의 저작권 침해와 유통질서를 혼란에 빠지게 한다. 따라서 디지털 자원에 대한 지적 재산권 보호문제가 새로운 이슈로 떠오르게 되었다. 현재 디지털 콘텐츠에 대한 저작권 보호를 위해 암호와, 워터마킹, 그리고 CPSA(Content Protection System Architecture) 등과 같은 기술들이 개발되고 있다. 즉, 저작권 보호를 위한 기술은 소프트웨어적인 방법과 하드웨어적인 방법으로 양분되어 발전되고 있다. 그러나 이처럼 서로 다른 방식으로 개발된 기술들은 호환성과 상호 연계성 측면에서 문제점을 드러내고 있다. 따라서 본 연구에서는 하드웨어와 소프트웨어 접근 기술들의 특성과 문제점들에 대해 살펴보고 효과적인 멀티미디어 콘텐츠 보호를 위해 이 두 가지 기술을 제시하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.134-144
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• 2009

The Ubiquitous/Unified Communication Platform supports various multimedia communication tools such as VoIP, Email, Unified Messaging, Instant Messaging, Web Conferencing, Audio/Video Communication etc. In this paper we introduced the main functions and architecture of the Unified Communication Platform and we researched on the function analysis and design of the VoIP System that supports PC-to-PBX/PSTN Phone and PBX/PSTN Phone-to-PC communications through the connectivity and interoperation with PSTN.

• The KIPS Transactions:PartA
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• v.10A no.6
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• pp.723-728
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• 2003

In this paper, we propose the two-tiered proxy system that offers a seamless media service to mobile nodes in mobile computing environment. This proxy system is composed of a media proxy and a mobile proxy. We also propose the handoff protocol and the transmission mechanism for the seamless media service. The simulation result shows that the media service is improved in the two-tiered proxy system.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.3
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• pp.9-15
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• 2014

In the ubiquitous computing environment, a ubiquitous vehicle will be a communication node in the vehicular network as well as the means of ground transportation. It will make humans and vehicles seamlessly and remotely connected. Especially, one of the prominent services in the ubiquitous vehicle is the vehicle remote operation. However, mutual-collaboration with the in-vehicle communication network, the vehicle-to-vehicle communication network and the vehicle-to-roadside communication network is required to provide vehicle remote operation services. In this paper, an Internet-based human-vehicle interfaces and a network architecture is presented to provide remote vehicle control and diagnosis services. The performance of the proposed system is evaluated through a design and implementation in terms of the round trip time taken to get a vehicle remote operation service.

• Journal of Broadcast Engineering
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• v.3 no.1
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• pp.24-37
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• 1998

This paper presents a new interworking paradigm using service-level interworking functionality for provision of end-to-end interperability in Heterogeneous Network Environments such as ATM network to Internet, Internet to ATM network. PSTN to ATM network, etc. We propose the concept of the Service Interworking Broker. We also propose the functional architecture of the Interworking Broker. The middleMEN is implemented for evaluating the functions of the Interworking Broker

• JSTS:Journal of Semiconductor Technology and Science
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• v.12 no.1
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• pp.10-17
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• 2012

This paper presents a clock regenerator using two $2^{nd}$ order ${\sum}-{\Delta}$ (sigma-delta) modulators for wide range of dividing ratio as defined in HDMI standard. The proposed circuit adopts a fractional-N frequency synthesis architecture for PLL-based clock regeneration. By converting the integer and decimal part of the N and CTS values in HDMI format and processing separately at two different ${\sum}-{\Delta}$ modulators, the proposed circuit covers a very wide range of the dividing ratio as HDMI standard. The circuit is fabricated using 0.18 ${\mu}m$ CMOS and shows 13 mW power consumption with an on-chip loop filter implementation.

• Convergence Security Journal
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• v.10 no.3
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• pp.9-14
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• 2010

The network architecture and analysis model for evaluating the information security are presented to distribute the reliable and secure multimedia digital contents. Using the firewall and IDS, the function of the proposed model includes the security range, related data collection/analysis, level evaluation and strategy proposal. To develop efficient automatic analysis tool, the inter-distribution algorithm and network design based on the traffic analysis between web-server and user are needed. Furthermore, the efficient algorithm and design of DRM/PKI also should be presented before the development of the automatic information security model.