• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.137-143
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• 2007

The P-ECLMS algorithm adapted the existing Post-Processing method occurs the distortion of the near-end signal at the double-talk situation. To solve this problem, we propose the SP-ECLMS algorithm which makes the Post-Processing coefficient differently at the case of the single-talk and the double-talk. When the correlation level is not output less than 30%, the proposed algorithm output the original signal to prevent the signal's distortion.

• International Commerce and Information Review
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• v.14 no.3
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• pp.31-47
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• 2012

The Eurozone was launched to set a goal on using the single currency perfectly in 1999. Using the Euro could get rid of exchange cost and cost of Foreign exchange risk management which was approximately 1% of each member's GDP. It was possible that members has maintained a stable level of inflation and stimulate investment and employment with low interest rate. In addition, they could lead to economic growth and investment as well as increase the Euro demand in financial market. Especially, members has used the Euro as the method of payment on trade each other so that the volume of trade among the Eurozone members has increased continuously which was called "the effect of single market." This paper analyzes the correlation between using the Euro and members' export/import by using random effect estimation and fixed effect estimation. As a result, Eurozone members can get export decreasing effect of 4.68% and import increasing effect of 10.5% respectively on average by using the Euro.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5C
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• pp.478-486
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• 2007

Double-talk detection errors can result in either large residual echo or distorting the near-end talker's input speech. Thus accurate double-talk detection is an important problem in the acoustic echo canceller to improve the speech quality. In the double-talk detection algorithm using a cross-correlation coefficient, double-talk detection errors can occur in the initial convergence period of an adaptive filter or in noisy environment since the cross-correlation coefficient becomes large in such situations. In this paper, we propose a new double-talk detection algorithm based on the cross-correlation method using a normalized error signal power to reduce the double-talk detection errors. The experimental results have shown the performance improvement of an acoustic echo canceller as well as the noise-robustness of the proposed double-talk detector.

• Journal of Korean Electronics
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• v.17 no.10
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• pp.61-65
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• 1997

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.6
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• pp.628-633
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• 2014

This paper proposes a performance improvement method of the conventional double talk detection method which can operate before convergence of the echo canceller. The proposed method estimates the coefficients of the linear predictive coding(LPC) filter by using the primary input signal. The time-varying threshold for double talk detection is determined based on the LPC filter gain of the primary input signal level. The proposed method can reduce not only false detection rate which means wrong detection of single talk as double talk but also double talk detection delay. Computer simulation was performed using a long-term real speech signals. It is shown that the proposed method improves the conventional method in terms of lowering the false detection rate and shortening the detection delay.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.541-544
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• 2000

본 논문은 부밴드별 반향제거 필터 뱅크를 구현하기 위한 가중 Overlap-add 적응필터를 이용한 단일 채널 음향 반향 제거기를 제안한다. 기준 입력 신호의 고유치 분포율에 의존하여 수렴 특성이 결정되는 NLSM알고리즘을 사용하여 전대역 처리 과정에서 발생하는 수렴성능의 저하를 방지하고, 효율적인 블록별 병렬 처리가 가능한 부밴드 처리기법인 가중 Overlap-add 방식을 적용한 적응 반향제거기의 성능을 고찰한다 또한 본 논문에서는 동시 통화 검출을 위한 전용 필터와 에너지 비교 방법을 동시에 사용하는 새로운 형태의 동시통화 검출 기법을 제안한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.203-208
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• 2013

In this paper, we proposed a performance improvement method of the double talk detector which can operate before the echo canceller converges. Microphone input signal is filtered by the linear prediction filter and this filtered signal is used for detection. The coefficients of the linear prediction filter are given by the far-end talker signal. During single talk, filtered signal has low power since the characteristics of the echo signal is similar with those of the far-end talker signal. But, during double talk, the filtered signal does not have low power because the signal of different characteristics is included in the microphone signal. Double talk is detected by this difference. Simulations using real speech signals verified that the proposed method outperformed the conventional methods.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.162-166
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• 2009

In this paper, we propose a novel approach of an acoustic echo cancellation (AEC) algorithm which is differently adopted in the relevant period condition by the suppression parameter of a parametric wiener filter (PWF). The PWF uses the suppression parameter to compensate uncertainty of acoustic echo signal estimation. The existing PWF method using the fixed suppression parameter derives the distortion of the near-end signal at the double-talk. To solve this problem, the boundary condition is devised using decision of the double-talk detection (DTD) algorithm and voice activity detector (VAD). The boundary condition makes it possible to treat differently depending on the case of the single-talk and double-talk. According to the experimental results, the proposed approach is found to be effective for acoustic echo cancellation using the boundary condition.

• International Area Studies Review
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• v.14 no.1
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• pp.203-219
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• 2010

Nowadays an instability of the exchange rate on accounts of global finance crisis brings on a lot of an economic damage such as recession, decreasing of total trade and so on. However some countries which belong to be membership of the eurozone could escape economic slump shortly and easier than others. The reason for this is that they share with the Euro as a their own currency which is the second vehicle currency all of the world. This paper analyzes the correlation of joining the Euro zone and trade with pooled OLS, random effect estimation, and fixed effect estimation. A membership of the Euro zone are able to increase trade 11.3% ~ 25.3% one another on average since some country belongs to the Euro zone. It is very important for some countries which have a plan to affiliate the Euro zone sooner or later to realize economic effect because of a protection of the Euro zone as well as political power.

• The Journal of the Acoustical Society of Korea
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• v.19 no.8
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• pp.35-46
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• 2000

In this paper, we propose a subband acoustic echo canceller using the weighted Overlap-add adaptive filter bank to prevent the decrease of convergence speed in full-band US processing, and make it possible to realize the adaptive filter in block-parallel processing, this paper introduces the weighted overlap-add technique for subband echo canceller. Moreover, we propose a new double-talk detector which employs dedicated filter in addition to the energy comparison method simultaneously. The computer simulation results show that the performance of the proposed subband adaptive echo canceller double-talk detection