• 한국임상수의학회지
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• 제14권1호
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• pp.48-55
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• 1997

This study eas conducted to assess the spectrographic analysis agter vocal cordectomy in which procedures included biopsy punch per os, laryngofissure and lactic acid injection to the vocal cord. There were significant difference in dominant frequency(DF) of spectrograms between normal and all surgical procedures for vocal cordectomy at 1 day (p<0.01). Vocal cordectomy(laryngofissure) revealed significant differences in minimum frequency of call (MIFC) and DF during the period of observation after surgery (p<0.01). In lactic acid injextion group, there were also significant differences in DF and maximum frequency of call (MAFC) variables (p<0.01).

• 천문학회보
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• 제43권1호
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• pp.39.2-39.2
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• 2018

GW170817/GRB170817A establishes a double neutron star merger as the progenitor of a short gamma-ray burst, starting 1.7 s post-coalescence. GRB170817A represents prompt or continuous emission from a newly formed hyper-massive neutron star or black hole. We report on a deep search for broadband extended gravitational-wave emission in spectrograms up to 700 Hz of LIGO O2 data covering this event produced by butterfly filtering comprising a bank of templates of 0.5 s. A detailed discussion is given of signal-to-noise ratios in image analysis of spectrograms and confidence levels of candidate features. This new pipeline is realized by heterogeneous computing with modern graphics processor units (GPUs). (Based on van Putten, M.H.PM., 2017, PTEP, 093F01.)

• 한국음향학회지
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• 제43권2호
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• pp.234-242
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• 2024

본 논문에서는 그래프 신경망을 이용한 수동소나 신호 분류 알고리즘을 제안한다. 제안하는 알고리즘은 스펙트로그램을 영상 패치로 분할하고, 인접 거리의 영상 패치 간 연결을 통해 그래프를 표현한다. 이후, 표현된 그래프를 이용하여 그래프 합성곱 신경망을 학습하고 신호를 분류한다. 공개된 수중 음향 데이터를 이용한 실험에서 제안된 알고리즘은 스펙트로그램의 선 주파수 특징을 그래프 형태로 표현하며, 92.50 %의 우수한 분류 정확도를 갖는다. 이러한 결과는 기존의 합성곱 신경망과 비교하여 8.15 %의 높은 분류 정확도를 갖는다.

• ETRI Journal
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• 제46권1호
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• pp.22-34
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• 2024

Exposure to varied noisy environments impairs the recognition performance of artificial intelligence-based speech recognition technologies. Degraded-performance services can be utilized as limited systems that assure good performance in certain environments, but impair the general quality of speech recognition services. This study introduces an audiovisual speech recognition (AVSR) model robust to various noise settings, mimicking human dialogue recognition elements. The model converts word embeddings and log-Mel spectrograms into feature vectors for audio recognition. A dense spatial-temporal convolutional neural network model extracts features from log-Mel spectrograms, transformed for visual-based recognition. This approach exhibits improved aural and visual recognition capabilities. We assess the signal-to-noise ratio in nine synthesized noise environments, with the proposed model exhibiting lower average error rates. The error rate for the AVSR model using a three-feature multi-fusion method is 1.711%, compared to the general 3.939% rate. This model is applicable in noise-affected environments owing to its enhanced stability and recognition rate.

• 음성과학
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• 제11권3호
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• pp.69-81
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• 2004

The purpose of this experimental study was to investigate characteristics of Korean vowels uttered by Japanese speakers. Eight Korean Vowels were uttered three times by ten male Korean and Japanese, female Korean and Japanese, respectively. Formant Frequencies were measured from sound spectrograms made by the Pitch Works. Results showed that female Japanese speakers uttered Korean vowels more similar to those uttered by Korean native speakers than did male Japanese speakers.. In particular, male Japanese speakers have articulatory problems pronouncing the back vowels(/ㅓ/, /ㅡ/, /ㅜ/). It appears that the width of male speakers' articulatory movements is comparatively narrower than those of female speakers.

• 천문학논총
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• 제30권2호
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• pp.229-230
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• 2015

The results of spectral studies of the CTTS type young star RY Tau with spectrograms of the ultraviolet and the visual ranges are presented. We show the first detection of periodic variability of the emission line intensities in UV and visual ranges with a period of 23 days.

• 한국융합학회논문지
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• 제10권9호
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• pp.193-198
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• 2019

본 연구는 근위축성측삭경화증(amyotrophic lateral sclerosis, ALS)으로 진단된 여성을 대상으로 음향음성학적 스펙트로그램 분석을 이용하여 11개월 동안 모음과 이중모음의 포먼트 변화(vowel formant variation)를 분석하였다. 검사어는 단모음 /a, i, u/와 이중모음 /h + ja + da/, /h + wi + da/, /h +ɰi+ da/를 이용하였다. 발화자료는 'Alvin' 프로그램을 이용하여 모니터에 제시된 단어읽기과제를 통해 수집되었고, 녹음환경은 nyquist frequency는 5,500Hz, sampling rate는 11,000Hz으로 설정하였다. 녹음자료는 스펙트로그램을 이용하여 강도, 음도와 이중모음의 포먼트를 분석하였다. 분석결과, ALS의 진행과정에서 기본주파수와 강도가 저하되었고, 단모음에서의 포먼트 변화보다는 이중모음의 포먼트 기울기의 감소가 특징으로 확인되었다. 이 결과는 병의 진행에 따른 ALS의 모음왜곡이 혀와 턱의 협응력 감소에 기인함을 시사한다.

• Animal Systematics, Evolution and Diversity
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• 제29권4호
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• pp.294-307
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• 2013

The burrowing-cricket genus Velarifictorus Randell, 1964 is reviewed in Korea, comparing with morphologically resembled genus Lepidogryllus Otte and Alexander, 1983 for the first time. First, Velarifictorus aspersus borealis Gorochov, 1985 is confirmed from only restricted area of southern regions in Gyeongsangnam-do and Jeollanam-do. Second, Velarifictorus micado (Saussure, 1877) is confirmed from nearly all around the Korean peninsula including North Korea. Third, the previously not recorded Velarifictorus ornatus (Shiraki, 1911) is newly recognized from South Korea. Relating to the genus Velarifictorus, the resembled genus Lepidogryllus Otte and Alexander, 1983 and its species Lepidogryllus siamensis (Chopard, 1961) com. & stat. nov. is studied and compared with Velarifictorus members. A key, descriptions, tables, photographs, figures, oscillograms and spectrograms of calling sounds are provided to aid identification between the four similar species.

• 음성과학
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• 제12권2호
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• pp.7-16
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• 2005

The purpose, this experimental study was to identify pronunciation difficulties between male and female Korean speakers in their articulation of English vowels. Ten English mono-syllabic words were spoken six times by six male and six female college students. Formant frequencies were measured from sound spectrograms made by Pitch Works. Results show that Korean female speakers uttered English vowels more similar to those uttered by English native speakers than did Korean male speakers. While Korean male speakers could not readily distinguish between /i/ and /I/, /u/ and /v/, and /$\epsilon$/ and /ae/, respectively, Korean female speakers had difficulty only with /$\epsilon$/ and /ae/. The tentative results suggests that on the whole Korean speakers have difficulty in discriminating tense vowels from lax vowels, and they also have articulatory problems pronouncing low and back vowels such as /ae/. /a/ and /c/.

• 음성과학
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• 제10권2호
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• pp.223-236
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• 2003

The purpose of this experimental study is to investigate characteristics of English pitch accents uttered by Korean speakers. Six English sentences were uttered five times by fifteen male undergraduate and graduate students from three groups, Seoul, Yongnam and Honam dialect speakers. We compared the subjects' data with the data of a native speaker of English as model pronunciation of English pitch accents. Acoustic features(Fo, duration, amplitude) were measured from sound spectrograms made by the PC Works. Results showed that (1) acoustic features of English pitch accents are Fo and duration for the native speaker and Korean speakers altogether, (2) Seoul dialect speakers uttered English pitch accents more similarly to the English native speaker than the other dialect speakers and (3) Korean speakers generally have difficulties in pronouncing L* accents. It appears that Korean speakers have more problems in pronouncing L* accents than H* accents.