• Journal of Korea Multimedia Society
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• v.3 no.3
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• pp.263-271
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• 2000

In this paper, an acoustic echo canceller(AEC) is implemented by ADSP-2181. This AEC uses a noise robust adaptive algorithm and a postprocessing method which attenuates residual echo using cross-correlation between estimated error signal and microphone input signal. We propose new postprocessing method that uses two thresholds to prevent signal distortion after postprocessing and to improve the performance of AEC without extra computational burden. Through experiments using a 16 bit fixed-point DSP board (ADSP-2181 EZ-KIT Lite board), it is shown that the noise robust adaptive algorithm performs well in the double-talk situations and the convergence speed is comparable to NLMS. Using the postprocessor, ERLE is improved about 20 dB. As a result, the AEC with a postprocessor shows better performance than conventional ones.

• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.35-43
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• 1999

In this paper, a new robust adaptive algorithm and a post-processing method are proposed to improve the performance of AEC without computational burden. Its step-size is normalized by the sum of the powers of the reference input signal and the desired signal. When the near-end speaker's speech and noise are applied into the microphone, the step-size becomes small and the misalignment of coefficients are reduced. To reduce the residual echoes, a new post-processing method, which is co-operated with the proposed noise-robust adaptive algorithm, is proposed in this paper. The method is based on the correlation of the desired signal and the estimation error signal. The residual echoes are attenuated as proportional to the correlation normalized with the power of desired signals. The normalized correlation plays a role as Wiener filter for residual echoes. In the double-talk situation, the estimation error signals, that are residual echoes, dominantly include the near-end speaker's speech and the normalized correlation closes to 1. Therefore, the near-end speaker's speech can be transmitted without being attenuated. When the desired signals consists of only the acoustic echoes, the residual echoes are mostly attenuated and canceled by the proposed post-processor. The computation of AEC using the proposed post-processor is comparable to NLMS algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.12
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• pp.1346-1351
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• 2014

We propose a novel approach for stereophonic acoustic echo suppression using spectro-temporal filtering based on soft decision. Unlike the conventional approaches estimating the echo pathes directly, the proposed technique can estimate stereo echo spectra without any double-talk detector. In order to improve the estimation of echo spectra, the extended power spectrum density matrix and echo overestimation control matrix are applied on this method. In addition, this echo suppression technique is based on soft decision technique using speech absence probability in STFT domain. Experimental results show that the proposed method improves compared with the conventional approaches.

• The Journal of the Korean bone and joint tumor society
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• v.3 no.2
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• pp.69-79
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• 1997

Objective : The objective of this study was to compare expression of various proto-oncogenes and rates of apoptosis in osteosarcoma patients. Modulation of apoptosis may influence resistance to chemotherapy and therefore affect the outcome of cancer treatment. Osteosarcoma is one of the most fatal malignancies in young adolescents and investigation of the role of apoptotic cell death is warranted in relation to chemotherapy and tumor outcome. Design : The terminal deoxynucleotidyl transferase to exposed 3'-hydroxyl termini of DNA (TUNEL method) staining method has been applied for the in situ detection of DNA double strand breaks. Patients : Thirty-three osteosarcomas in various stages of differentiation from twenty-nine patients were investigated immunohistochemically for p53, Bcl-2 and TUNEL method for apoptosis. Results and conclusion; We have found that higher level of wild type p53 were correlated with enhanced expression of apoptosis. Increased apoptosis rates were found in cases of negative Bcl-2 expression. In the present study, we have concluded that a significant proportion of osteosarcoma, a tumor in which resistance to chemotherapy often occurs, express high levels of p53 and low levels of Bcl-2. Our data provide further evidence for cross-talk between Bcl-2 and p53 and suggests that these genes are important determinants of drug-induced apoptosis.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.449-458
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• 2023

Many people think that sign language is only for people who are deaf and cannot speak, but of course it is necessary for people who want to talk with them. One of the biggest challenges in ASL(American Sign Language) alphabet recognition is the high inter-class similarities and high intra-class variance. In this paper, we proposed an architecture that can overcome these two problems, which performs similarity learning to reduces inter-class similarities and intra-class variance between images. The proposed architecture consists of the same convolutional neural network with a double configuration that shares parameters (weights and biases) and also applies the Keras API to reduce similarity learning and variance through this pathway. The similarity learning results the use of the dual CNN shows that the accuracy is improved by reducing the similarity and variability between classes by not including the poor results of the two classes.

• The Journal of the Acoustical Society of Korea
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• v.28 no.5
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• pp.483-490
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• 2009

In this paper, we develop a speech interface that has acoustic echo cancelling and barge-in functionalities in the car environment. In the echo canceller, DT (Double-Talk) detection algorithm using the correlation coefficients between reference and desired signals can make DT detection errors often in the background noise. We reduce the DT detection errors by using the average power of noise and echo estimated from the input signal. In addition, to make it possible for drivers to give speech command to the system by interrupting the speaker output, barge-in functionality is implemented with the combination of DT detection and appropriate gain control of the speaker output. Through the computer simulation with the assumed car environment and experiment in the real laboratory environment, implemented speech interface has shown good performance in removing acoustic echo signals in the noisy environment with proper operation of barge-in functionality.

• Journal of Korean Classical Literature and Education
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• no.35
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• pp.87-122
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• 2017

1) The passage "Sila seongdae so-seongdae cheonha daepyeong nahu-deog (新羅盛(聖)代 昭盛代 天下大平 羅侯德)" of the Korean Dynasty , corresponds to the primary passage of Cheonyong Rang Manghaesa(처용랑 망해사)>. These passages are ironic expressions of King Heongang's reign. This passage can therefore be interpreted as having the meaning of "People talk about King Heongang who ruined the kingdom. The bright politics of Silla's loyalty is the virtue of King Heongang." 2) "Cheoyong aba isi insaeng-ae sangbuleo hasilandae isi insaeng-ae samjaepalnan-i ilsi somyeol hasyatda (處容 아바 以是人生애 相(常)不語시란 以是人生애 相(常)不語시란 三災八難이 一時消滅샷다)." This was said by Cheoyong(처용), who was unable to reveal his anger while witnessing his wife being raped by Yuk-sin(疫神). This passage means, "Father Cheoyong(처용), in this world if a man does not express anger about the absurdity of the world, he can escape from catastrophe," or, "Father Cheoyong (처용), because in this world you had not expressed anger about the absurdity of world, you could escape from catastrophe." 3) In "maa-man maa-man haniyeo sibi jegug-i moda jiseo syeon aeu cheoyongbi-hal maa-man haniyeo (마아만 마아만 니여 十二諸國이 모다 지 셰온 아으 處容아비 마아만 니여)," the most likely interpretation of Maa is "마아(麻兒)," which means "scarecrow." In this way, this passage emphasizes that Cheyong(처용) is not a scarecrow, but a representative of the eyes of all people in all kingdoms. 4) In "meoja oeyaja logliya ppallina nae singohal maeyara (머자외야자 綠李야 리나 내 신고 야라", meoja (머자) is the double arranging shape of meotda(멎다), and oeyaja(외야자) is the double arranging shape of oeda(외다); those characters mean "ugly" and "wrong for each other." Additionally, Rokri(綠李) can be regarded as an administrator in blue or black clothes who is performing an errand of the yuksin(疫神).