• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1025-1033
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• 2011

In this paper, we introduce the contactless power transmission device for transmitting the power with the resonant characteristic of the cavity resonator. When transmitting the power, the contactless power transmission device begins to work in the condition where the transceiver adheres closely. The transceiver is electrically separated because there is no conductive terminal outside and the size of the receiver required for the electric power transmission can be minimized. The cavity resonator comprises slots for the input port and output port in the upper side conductor plate of the cavity and forms the input port and output port using the stripline structure at this upper part. The some of output port is separated from it and the electric power receiver is formed thus the union can be possible. The rest except electric power receiver become the electric power transmitter, which includes the input port of stripline-slot coupling, cavity, and the slot of the output port. If the transmitter and the receiver are combined, they become the form in which the electricity is transferred from the input port to the output port in a cavity resonator. The center frequency of the contactless power transmitter manufactured is 5.782 GHz. and $S_{21}$ is measured as -1.07 dB. It is confirmed that the high electric power transfer rate is approximately 78 %.

• The KIPS Transactions:PartC
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• v.11C no.6 s.95
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• pp.773-780
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• 2004

In this paper, we measured the transmission characteristics of a MPEG2 and a DV that are typical stream-type traffics on the very high speed network and carried out the subjective evaluation of end users for these stream-types. In the subjective evaluation of these stream-type data, video quality evaluation is based on ITU-R BT.500-1 and audio qualify evaluation is based on ITU-R BS.1116-1. Also experiment method to acquire the subjective evaluation of end users is selected the 5 grades method of DSCQS. Under the same condition, in case of MPEG2, the evaluation grade of the video and the audio duality becomes deteriorated at the load rate of $54\%$ that network traffic increases rapidly. In case of DV the evaluation grade of video duality began decrease, but the degree of the change was slower than MPEG2 at the same load rate. Moreover the subjective evaluation grade of end users was superior to load rate $70\%$ in case of DV audio quality, traffic and QoS control that consider the subjective evaluation of end user is required. Conclusively, in case of MPEG2, we can perform traffic control that only use the actual measurement values on the network. However in case of DV, we can perform traffic control that the actual measurement values on the network and the subjective evaluation of end users are considered at the same time.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.38-40
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• 2012

비디오 서버는 다수의 비디오 요청을 동시에 서비스하기 때문에 통신망 대역폭을 공평하고 효율적으로 활용하는 것이 중요하다. 모바일 통신망에서 클라이언트들의 재생 버퍼 수준을 이용하여 VBR 비디오 스트림을 전송하는 스케쥴링 알고리즘들이 본 논문에서 제시되었다. 요청된 비디오 재생시 서비스 품질과 실시간적 성능을 향상시키기 위하여 비디오 서버는 일시적으로 버퍼 수준이 낮은 비디오 요청 작업을 우선적으로 서비스하고자 더 많은 대역폭을 할당하는 실시간 스케쥴링 알고리즘을 수행한다. 버퍼 수준이 상이한 모바일 클라이언트들에게 공평한 서비스와 부하 균형이 제공되는 시뮬레이션 결과가 나타났다.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.134-139
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• 2008

In this paper, we propose an analysis model for the performance of channel error probability in Stream Control Transmission Protocol (SCTP) using Markov model. In this model it is assumed that the compressor and decompressor work in Unidirectional Mode. And the average throughput of SCTP protocol is obtained by finding the throughputs of when the initial channel state is good or bad.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.287-290
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• 1999

In the transmitter of optical fiber transmission systems, a time-division multiplexer combines several parallel data streams into a single data stream with a high bit rate. In this paper, we design a 2:1 (2-channels) time-division multiplexer using SiGe HBT with emitter size of 2$\times$8${\mu}{\textrm}{m}$$^2$. The operation speed is 10Gbps, the rise and fall times of 20-80% are 34ps and 35ps, respectively and the dissipation of power is 0.86W.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.251-254
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• 2003

DMB is a next-generation multimedia broadcasting system that not only enables digital broadcasting services such as transmission of CD-duality audio, traffic information, and real-time stock information, but also allows reception of high-quality digital TV in high-speed driving conditions. In the DMB system, MPEG-2 TS(Transport Stream) multiplex method and MPEG-4 System SL(Sync Layer) have been selected as the delivery layer. In this paper, an efficient interface scheme between an MPEG-2 TS processing hardware and software-implemented MPEG-4 system within a DMB terminal device is proposed.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.635-637
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• 1999

기존의 인터넷 기반 데이터 서비스는 'Best-effort' 정책으로 멀티미디어 서비스를 위한 트래픽 제어(traffic control) 기능을 제공하지 못한다. 그러므로 실시간 데이터 전송을 기반으로 제공되는 VOD(Video-on-Demand) 서비스는 사용자가 원하는 QoS(Quality of Service)를 제공할 수 없다. 따라서 인터넷 상에서 트래픽 제어 기능을 갖춘 중개자를 두어 VOD 서비스를 제공하는 방법에 대해 제안한다. 중개자의 주요 기능은 비디오 서버와 클라이언트 사이에 비디오 데이터의 버퍼링 기능을 이용하여 실시간 트래픽 제어를 수행한다. 이런 기능을 가진 중개자를 에이전트라 부르고, 에이전트에 대한 설계 및 구현에 대해 기술한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1744-1759
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• 2000

In this paper a synchronized stream cryptosystem for secure link layer communication on a radio channel is designed. We have proposed new interleaving schemes to randomize a burst error and experimented with different types of interleaving schemes. The proposed techniques of interleaving schemes are : (1) interleaving scheme based on frame(2) interleaving scheme based on group. The proposed schemes are very robust in randomizing

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.280-282
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• 2003

SCTP (Stream Control Transmission Protocol)은 신뢰성있는 스트림 전송을 위해, 기존의 전송 프로토콜로 사용되어온 TCP/UDP 프로토콜의 장점을 살린 차세대 전송프로토콜 기술로, IETF SIGTRAN에서 개발한 표준이다. RFC 2960(SCTP)는 신뢰성 있는 데이터 전송이 기존의 전송프로토콜에 비해 뛰어나다는 평가를 받고 있다. 본 논문에서는 이러한 SCTP의 신뢰성을 바탕으로 에러 발생시 에러를 지각하고, 이를 기반으로 향상된 멀티미디어 서비스 품질을 제공할 수 있는 시스템과 그 방법에 대해 제안한다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.113-113
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• 2004