• 영어어문교육
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• 제17권3호
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• pp.119-139
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• 2011

Free-talking in Korea has recently been emphasized as a way of improving students' speaking ability outside of the classroom. The purpose of this study is to examine perceptions of free-talking, to understand what type of roles were played by or allotted between Korean students and international professors (IPs) and to look for effective speaking strategies for utilizing free-talking. Participants of this study were 68 university students and 23 IPs. The data collected through a survey type of questionnaire were analyzed by this researcher and the main findings indicate that students and IPs have somewhat different viewpoints about their concepts of free-talking. Students expressed varying viewpoints depending on their experience and class (year). In terms of the benefits, usefulness, and satisfaction of free-talking, students and IPs seem to be in more agreement with each other although the two groups have conflicting perceptions in the particular operation of free-talking, especially in terms of preparation and feedback. Students stated that they feel anxious, nervous, and that they struggle with peer pressure while free-talking. However, they feel that through free-talking they build up confidence and increase their speaking ability. Regarding roles, most professors play a helpful role as a guide or facilitator while students want professors to provide more suitable materials and to tutor them by means of appropriate feedback and strategies as well-prepared teachers like a prompter, participant or tutor in the timely manner. Finally, this paper proffers a few practical suggestions for activating free-talking and a discussion of the pedagogical implications.

• 대한간호
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• 제27권3호통권146호
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• pp.21-26
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• 1988

• 디지털산업정보학회논문지
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• 제12권1호
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• pp.43-50
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• 2016

This paper is on an acoustic echo canceller solving the double-talk problem by using the blind signal separation technology. The acoustic echo canceller may be deteriorated or diverged during the double-talk period. So we use the blind signal separation to detect the double talking by separating the near-end speech signal from the mixed microphone signal. The blind signal separation extracts the near-end signal from dual microphones by the iterative computations using the 2nd order statistical character in the closed reverberation environment. By this method, the acoustic echo canceller operates irrespective of the double-talking. We verified performances of the proposed acoustic echo canceller in the computer simulations. The results show that the acoustic echo canceller with this algorithm detects the double-talk periods well, and then operates stably without diverging of the coefficients after ending the double-talking. The merits are in the simplicity and stability.

• 한국전자통신학회논문지
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• 제12권3호
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• pp.419-426
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• 2017

본 논문은 기하학적 개념에 기반한 암묵신호분리를 이용하여 동시통화문제를 제어하는 음향반향제거기에 관한 것이다. 음향반향제거기는 동시통화 구간에서 성능이 저하되거나 발산하게 된다. 따라서 혼합된 마이크 입력신호로부터 근단화자신호를 분리해서 동시통화상태를 검출하기 위하여 암묵신호분리기술을 이용한다. 암묵신호분리는 미지의 입력신호들로부터 기하학적 개념에 기반하여 변형과 회전의 두 단계를 거쳐 근단화자신호를 추정해낸다. 컴퓨터 시뮬레이션을 통하여 이 음향반향제거기의 성능을 검증하였다. 동시통화 구간에서는 반향제거필터의 계수가 발산하는 것을 방지하기 위하여 계수 갱신작업을 중지하도록 하였다. 시뮬레이션 결과, 이 방법을 사용한 음향반향제거기는 암묵신호분리의 빠른 수렴속도로 인해 동시통화의 유무에 상관없이 안전하게 동작함을 확인하였다.

• 융합신호처리학회논문지
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• 제4권3호
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• pp.15-20
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• 2003

핸즈프리 마이크를 이용한 원격회의나 원격 통신 시스템과 같은 몇 가지의 응용분야에서, 음성 신호는 주위 잡음뿐만 아니라 마이크와 스피커사이의 결합에 의해 발생하는 에코에 의해서 왜곡되기 쉽다. 게다가 채널 왜곡이나 부가적인 잡음을 포함한 환경 잡음들은 원래의 입력 음성신호에 영향을 미치리라 고려된다. 본 논문에서는, 이러한 핸즈프리 음성에 있어서의 음성 인식률을 향상시키기 위해 에코 제거기와 최대 사후 추정(MAP)을 이용한 새로운 접근방식을 소개한다. 이 접근방식에서, 제안된 시스템이 에코를 포함한 주위 잡음 환경에서의 핸즈프리 음성인식에 효과적이라는 것을 보여준다 또한, 실험 결과는 에코 제거기와 MAP 환경적응 기술의 결합 시스템이 에코와 잡음 환경에 잘 적응하는 것을 보여준다.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2005년도 추계 학술대회 발표논문집
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• pp.151-154
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• 2005

원거리 음성인식에서 인식률의 성능향상을 위해 필수적인 다채널 마이크 환경에서 방 안의 도처에 분산되어있는 원거리 마이크를 사용하여 TV, 조명 등의 주변 환경을 음성으로 제어하고자 한다. 이를 위해 각 채널의 인식결과를 통합하여 최적의 결과를 얻고자 채널의N-best 결과와 N-best 결과에 포함된 hypothesis의 frame-normalized likelihood 값을 사용하여 Bayesian network을 훈련하고 인식결과를 통합하여 최선의 결과를 decision 하는데 사용함으로써 원거리 음성인식의 성능을 향상시키고 또한 hands-free 응용을 현실화하기위한 방향을 제시한다.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제23권2호
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• pp.93-111
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• 2020

The purpose of this study was to examine mathematics teachers' perceptions of multicultural education. To achieve this goal, the study explored how 10 elementary mathematics teachers noticed multicultural content in a mathematics textbook. Building upon noticing framework (Jacobs, Lamb, & Philipp, 2010), we first examined teachers' attention toward multicultural content in a mathematics textbook. Then, we examined teachers' interpretation of the content. We employed a content analysis approach to examine the collected data. The results indicated that most mathematics teachers held a content integration perspective. Their view was that "multicultural education" referred to learning about the diverse cultures of different countries. Moreover, although they noticed some multicultural content in the textbook, they wanted to discuss them in superficially descriptive ways and avoid talking about social justice issues. Additionally, some teachers believed that mathematics is a culture-free subject. They argued that multicultural content should not be presented in mathematics textbooks. We also discussed uncommon themes, which were reported by only a few mathematics teachers.

• 전자공학회논문지 IE
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• 제44권4호
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• pp.1-10
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• 2007

본 논문에서는 송수화기를 사용하지 않고도 통화 가능한 핸즈프리 통화방식에서 스피커의 출력신호가 마이크로 입력되는 음향반향(acoustic echo)을 효과적으로 제거할 수 있는 음향반향 제거기가 적용된 핸즈프리 전화기의 구현에 관하여 연구한다. 적응필터만을 적용한 기존의 음향반향 제거기는 반향신호와 동시통화의 문제를 동시에 해결하는데 있어서 많은 어려움을 갖고 있다. 이를 해결하기 위해서 본 논문에서는 modified NLMS 알고리즘이 적용된 적응필터, 두 개의 독립된 망각인자(forgetting factor)를 이용하여 원단신호의 음성구간을 정확하게 검출하는 VAD, 마이크신호와 잔여반향신호의 상호상관계수를 이용하여 동시통화 구간을 신속하고 정확하게 판단하기 위한 동시통화 검출기, 그리고 VAD와 동시통화 검출기를 이용한 출력제어부로 구성된 음향반향 제거기를 제안한다. 이러한 구조의 음향반향 제거기가 적용된 핸즈프리 전화기는 기존의 핸즈프리 전화기와 차별되게 반향도 없고 동시통화도 원활한 성능을 보여준다.

• 말소리와 음성과학
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• 제7권2호
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• pp.149-156
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• 2015

We propose a new method for automatic fluency scoring of English speaking tests spoken by nonnative speakers in a free-talking style. The proposed method is different from the previous methods in that it does not require the transcribed texts for spoken utterances. At first, an input utterance is segmented into a phone sequence by using a phone recognizer trained by using native speech databases. For each utterance, a feature vector with 6 features is extracted by processing the segmentation results of the phone recognizer. Then, fluency score is computed by applying support vector regression (SVR) to the feature vector. The parameters of SVR are learned by using the rater scores for the utterances. In computer experiments with 3 tests taken by 48 Korean adults, we show that speech rate, phonation time ratio, and smoothed unfilled pause rate are best for fluency scoring. The correlation of between the rater score and the SVR score is shown to be 0.84, which is higher than the correlation of 0.78 among raters. Although the correlation is slightly lower than the correlation of 0.90 when the transcribed texts are given, it implies that the proposed method can be used as a preprocessing tool for fluency evaluation of speaking tests.

• The Korean Journal of Pain
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• 제20권2호
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• pp.174-180
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• 2007

Background: The diagnosis of trigeminal neuralgia (TN) is based on only clinical criteria. The purpose of this study was to estimate the clinical manifestations of TN patients treated at our pain clinic. Methods: A total of 341 patients with TN from Jan. 2004 to Dec. 2006 was evaluated the intensity, site, and onset of pain, facial sensation, duration of pain attack, pain free interval, triggering factors, and effects of the previous treatments with TN specific questionnaire and interview at the first visit of our pain clinic. Results: About 80% of the patients were over 50 years of age and 256 (75%) patients were women. Average durations from first attack of their pain and from current pain attack were 7 years and 16 weeks, respectively. The two most frequently involved trigeminal nerve branches were maxillary (40%) and mandibular (39%) branches. Three quarters of the total patients experienced only paroxysmal pain that lasted less than one minute. About 90% of patients had pain free period at least one time. Most common triggering factors were chewing (88%), brushing teeth (82%), washing face (79%), and talking (70%). Only 16 patients (5%) had no previous treatment and the others had more than one treatment, such as medication (68%) and interventional procedures (35%). The most common reasons for early discontinuation of carbamazepine were dizziness, ataxia, and vomiting. Conclusions: TN has specific clinical features of pain, which should be considered at diagnosis.