• The Journal of the Acoustical Society of Korea
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• 제28권1E호
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• pp.29-34
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• 2009

MPEG4 High Efficiency Advanced Audio Coding (HE-AAC) and MPEG Surround are one of the most efficient combinations for low bit rate multi-channel audio coding. Based on the fact that these two codecs have identical quadrature mirror filter (QMF) analysis and synthesis structures, we propose a dual-domain connection scheme for the codecs. Specifically two time-domain connection methods are analyzed and compared to the QMF subband-domain connection method. Experimental results show that both the time-domain connection methods cause no subjective sound quality degradation compared to the QMF subband-domain connection method, which verifies that one can select either of them depending on application scenarios.

• 대한수학회지
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• 제54권2호
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• pp.461-477
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• 2017

A dual substructuring method with a penalty term was introduced in the previous works by the authors, which is a variant of the FETI-DP method. The proposed method imposes the continuity not only by using Lagrange multipliers but also by adding a penalty term which consists of a positive penalty parameter ${\eta}$ and a measure of the jump across the interface. Due to the penalty term, the proposed iterative method has a better convergence property than the standard FETI-DP method in the sense that the condition number of the resulting dual problem is bounded by a constant independent of the subdomain size and the mesh size. In this paper, a further study for a dual iterative substructuring method with a penalty term is discussed in terms of its convergence analysis. We provide an improved estimate of the condition number which shows the relationship between the condition number and ${\eta}$ as well as a close spectral connection of the proposed method with the FETI-DP method. As a result, a choice of a moderately small penalty parameter is guaranteed.

• 한국전자파학회논문지
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• 제13권3호
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• pp.225-236
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• 2002

본 논문에서는 동일채널 이중편파를 적용하는 디지털무선중계장치의 직교편파간섭을 제거할 목적으로 직교편파간섭제거기(XPIC)의 이론적 모델링, 디지털 설계를 분석하였다. 또한 유한임펄스응답 여파기를 이용한 복소 시간영역 적응등화기(ATDE)를 설계하고, 이를 이용한 XPIC의 구조 및 제어방법을 ATDE와의 연동하여 제시하였다. XPIC와 ATDE를 연동으로 약 25㏈ 이상의 시그너쳐(signature)와 약 23㏈ 이상의 XPIC 개선인자를 얻을 수 있음을 모의실험으로 보였다. 설계된 직편파간섭제거기의 동작검증을 위해 동일채널 이중편파용의 64-QAM모뎀과 연동하여 탭의 수, 알고리즘의 수렴, 장치의 성능, 직교편파간섭제거기의 개선인자에 대한 결과도 검토하였다.