• 한국음향학회지
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• 제17권5호
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• pp.63-68
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• 1998

광대역 정보통신망(B-ISDN)에 적합한 직접 제공법의 스트리밍모드 비연결형 서버 는 단일 셀의 전송시간 동안 셀의 송·수신 및 룩업(lookup)을 수행해야 한다는 시간적인 제약을 받기 때문에 버스트 트래픽(Burst Traffic)이 발생했을 경우 셀 손실이 많다는 단점 을 가지고 있다. 따라서 본 논문에서는 ATM 망의 스트리밍 모드 비연결형 서버가 고속으 로 데이터를 처리하여 셀 손실을 줄일 수 있도록 하기 위해 DBLCAM을 제안하였으며, 입 력 VPI(Virtual Path Identifier)/VCI(Virtual Channel Identifier)에 대한 연결 번호를 출력하 는 기능의 포워딩 테이블 VPC맵을 제안된 DBLCAM과 이중 포트 SRAM을 이용하여 설계 하였다.

• 전자공학회논문지 IE
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• 제47권2호
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• pp.54-59
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• 2010

본 논문은 무선 데이터 네트워크에 적용 가능한 적응 프레임 길이 제어 방식을 가진 데이터 링크 프로토콜을 제안한다. 무선 데이터망은 수시로 변화는 에러 환경에 놓여 있다. 이런 에러 환경에서도 잘 적용할 수 있는 가변 프레임 제어 방식을 제안하고 그 성능을 분석하였다. 2상태 마코프 모델을 이용하여 채널 환경을 모델링하였다. 수치해석방식을 통하여 새롭게 제안한 방식이 다양한 종류의 에러환경에서도 좋은 성능을 발휘할 수 있음을 보여 주었다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 추계학술대회
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• pp.281-283
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• 2009

본 논문에서는 군집 소실 채널 상에서 동작할 수 있는 짧은 길이의 인터리빙 된 코드들의 성능을 분석한다. 먼저 좋은 성능을 갖는 짧은 길이의 그래프 부호와 해밍부호를 설계한다. 이 후 군집 소실에 잘 대응하기 위하여 인터리빙 기능을 채널 부호화 방법에 적용한다. 생성된 짧은 코드에 적용한 인터리빙 부호를 군집 소실에 최적의 성능을 보이는 Reed-Solomon (RS) 부호와 성능을 비교한다. 짧은 길이의 부호이므로, ML(Maximum Likelihood)방법과 BP(Belief propagation)의 두 가지 복호 방법들을 이용한 경우 성능의 차이 또한 비교해 본다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.113-116
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• 2001

Reed-Solomon(RS) code is the most powerful burst error correcting code. In Ois paper, the architecture for the adaptive RS encoder adaptable for multi QoS requirements or time-varying channel environments has been designed. In the adaptive RS code, the message length k and the error correction capability t are allowed to be variable so that the block length n is also variable. We proposed the architecture of the adaptive RS encoder by designing the optimal structure of Galois fields multiplier with comparison of fixed multiplier and variable multiplier. The proposed architecture is implemented in VHDL and verified with the simulation tool

• Journal of information and communication convergence engineering
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• 제4권2호
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• pp.58-61
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• 2006

A key issue toward mobile multimedia communications is to create technologies for broadband signal transmission that can support high quality services. Such a broadband mobile communications system should be able to overcome severe distortion caused by timevarying multi-path fading channel, while providing high spectral efficiency and low power consumption. For these reasons, an adaptive suboptimum decision feedback equalizer (DFE) for the single-carrier shortburst transmissions system is considered as one of the feasible solutions. For the performance improvement of the system with the short-burst format including the short training sequence, in this paper, the multiple-training least mean square (MTLMS) based DFE scheme with soft decision feedback is proposed and its performance is investigated in mobile wireless channels throughout computer simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권9호
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• pp.2266-2284
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• 2012

Recent studies have indicated that a significant improvement in wireless video throughput can be achieved by Cross Layer Design with Side-information (CLDS) protocols. In this paper, we derive the operational rate of a CLDS protocol operating over a realistic wireless channel. Then, a Rate-Distortion (R-D) empirical model for above-capacity Scalable Video Coding (SVC) is deduced to estimate the loss of video quality incurred under inaccurate rate estimation scenarios. Finally, we develop a novel Unequal Error Protection (UEP) scheme which leverages the characteristics of LDPC codes to reduce the distortion of video quality in case of typically-observed burst wireless errors. The efficacy of the proposed rate adaptation architecture over conventional protocols is demonstrated by realistic video simulations using actual IEEE 802.11b wireless traces.

• 한국통신학회논문지
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• 제22권7호
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• pp.1403-1410
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• 1997

Because streaming mode connection server suitable to wide area ATM networks performs transmission, reception and lookup with time restriction for the transmission time of a cell, it has demerits of large cell loss incase that burst traffic occurs. Therefore, in this paper to decrease cell loss we propose a high speed CAM (Content Addressable Memory) which is capable of processing data of streaming mode connections server at a high speed. the proposed CAM is applied to forwarding table VPC map which performs function to output connection numbers about input VPI(Virtual Path Identifier)/VCI(Virtual Channel Identifier). The designed high speed CAM consist of DBL(Dual Bit Line) CAM structure performed independently write operation and match operation and two-port SRAM structure. Also, its simulation verification and full-custom layout is performed by Hspice and Composs tools in 0.8 .$\mu$m design rule.

• 디지털콘텐츠학회 논문지
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• 제5권4호
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• pp.316-320
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• 2004

본 논문에서는 이미지 데이터의 저작권 보호를 위해 워터마크 삽입시 워터마크 영상에 DM-SS 기법을 적용하고 DM-SS 방식에서의 Burst성 에러에 강인한 Reed-Solomon 부호화를 적용하여 워터마크 복원에 대한 성능 개선을 하였다. 그리고 영상에 대한 외부 공격으로는 OFDM/QPSK 전송 시스템을 이용하여 전송 시 생기는 여러 가지 요인을 고려하였다.

• 전기학회논문지
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• 제56권11호
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• pp.2033-2035
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• 2007

This paper proposes a novel iterative LMS-based decision feedback equalizer for short burst transmission with relatively short training sequence. In the proposed equalizer, the longer concatenated training sequence can provide the more sufficient channel information and the reused original training sequence can provide the correct decision feedback information. In addition, the overall adaptive processing is performed using the low complexity LMS algorithm. The study shows the performance of the proposed method is enhanced with the number of iterations and, furthermore, better than that of the conventional LMS-based DFEs with the training sequence of longer or equal length. Computational complexity is increased linearly with the number of iterations.

• 한국통신학회논문지
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• 제21권7호
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• pp.1833-1841
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• 1996

Recently, by emerging of the ALE techniques that make it possible to providereliable communications link automatically, high frequency communiation is newly used as emergency communication and back-up for satellite communications. ALE signal is transmitted in burst, and the received signal is subject to distortions by detrimental multipath fading channels. In the case of that channel, the performance of ALE system is highly dependent upon that of synchronization techniques. In this paper, M-ary FSK signals are detected by a bank of bandpass filter, which is implemented using recusive DFT(Discrete Fourier Transform). Also an acquisition and trancking algorithm are designed uisng parallel structure and early-late-gate methods respectively. Finally, we verify the performance ofthe proposed synchronization algorithm by the computer simulation.