• Proceedings of the Korea Institute of Convergence Signal Processing
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• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
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• pp.41-44
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• 2001

In the wide variety of radio propagation channel models, frequency selective fading which from multipath waves and diversity noises, electric and electronic devices ...etc in our environment, change characteristics of the sub channels in the wide bandwidth. so orthogonality among the OFDM subcarriers would be distorted and ICI(Inter Channel Interference), ISI(Inter Symbol Interference) be generated. This paper investigate BER characteristics of the OFDM System using Subband Grouping Method which adopted different channel modulation for each subband.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.63-66
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• 2004

본 논문에서는 채널간간섭 자기소거를 위한 부대역 부호화기법에 따른 직교 주파수분할다중화의 첨두전력대 평균전력비가 분석된다. 인접부대역에 대척신호를 할당하는 기존 상관부호화의 경우 전송신호열에서 형상성분이 발생되며, 이로 인하여 직교 주파수분할다중화 시스템의 첨두전력 대 평균전력비가 최대 3dB 가량 증가됨을 이론적$\cdot$실험적으로 검증한다. 그리고 이와 같은 형상성분을 제거할 수 있는 새로운 부대역 부호화기법이 제시된다. 여기서는 인접부대역에 할당되는 신호쌍의 위상차가 신호사상기의 출력에 따라 변화된다. 그 결과, 새로운 부대역 부호화기법이 적용된 시스템은 기존의 시스템보다 $2\~3dB$ 적은 첨두전력 대 평균전력비를 가지는 것을 확인할 수 있다.

• Journal of Broadcast Engineering
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• 제8권2호
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• pp.181-197
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• 2003

Notion Compensation(MC) technique using Sub-Band Coding with the hierarchical structure is efficient to estimate real motion. In the hierarchical pyramid method, low-band MC pyramid method is popular, where the upper layer estimate the glover motion and next lower layer estimate the local motion. The low-band MC pyramid scheme has two problems. First, because the quantization errors at lower layer are accumulated when using coding and quantizing, it is impossible to search the exact Motion Vector(MV) Second, because of the top-down search problem in the hierarchical structure, MV mismatch in upper layer causes serious MV in lower layer So. we propose new hierarchical MC pyramid method based on edge classification. In this Paper, we show that the performance of proposed Pass-band motion compensation pyramid technique is better than low-band motion compensation pyramid. Also, in the pyramid motion estimation, we propose initial MV estimation scheme based on the edge-pattern classification. As a result, we find that PSNR was increased.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제47권4호
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• pp.38-42
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• 2010

In this paper, a design method of the compact narrow band filter on the microstrip board is proposed using slot-type split spiral resonators. The design technique of this filter is based on cascading filter stages consisting of the combination of slot-type split spiral resonators, capacitive gaps between patches, and inductive grounded stubs with the meander configuration. By these means, it was possible to get the nearly symmetric frequency responses, adjustable bandwidths, compact sizes. And also excellent characteristic of the out-of-band rejection is achieved in contrast to the conventional filter design technique. The measured insertion loss shows good results about -3.47dB at the center frequency($f_0$=1GHz) and passband return loss is less than -12.62dB. The 3dB fractional bandwidth(FBW) is approximately 7.3%. The results of the frequency response measured on the fabricated band pass filter substrate show satisfactory agreement with the simulated frequency responses by the MWS(Microwave Studio) of CST in the region of interest.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 한국통신학회 1994년도 하계종합학술발표회 논문집
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• pp.147-150
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• 1994

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 한국통신학회 1995년도 추계종합학술발표회 논문집
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• pp.737-740
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• 1995

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 한국통신학회 1996년도 추계종합학술발표회 논문집
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• pp.633-636
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• 1996

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 한국통신학회 1992년도 추계종합학술발표회 논문집
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• pp.365-368
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• 1992

• The Journal of the Korea institute of electronic communication sciences
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• 제9권1호
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• pp.33-40
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• 2014

In this paper we propose new image coding using wavelet transform. The new method constructs hierarchical bit plane and progressively transports each bit plane. The Proposed algorithm not only supports multi-resolution, dividing original image into special band and various resolution using Antonini's wavelet basis function but also reduces blocking effects that come into JPEG. In encoding time this algorithm considers each band characters and priority of transport order, and applies to fast search of image.

• The Transactions of the Korea Information Processing Society
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• 제4권10호
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• pp.2640-2650
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• 1997

In this paper we propose new image coding using wavelet transform. The new method constructs hierarchical bit plane and progressively transports each bit plane. The proposed algorithms not only supports multi-resolution, dividing original image into special band and various resolution but also reduces blocking effects that come int JPEG. In encoding time this algorithm considers each band characters and priority of transport order, and applies to fast search of image.