• Journal of Veterinary Clinics
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• v.14 no.1
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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).

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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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.)

• The Journal of the Acoustical Society of Korea
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• v.43 no.2
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• pp.234-242
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• 2024

We propose a passive sonar signal classification algorithm using Graph Neural Network (GNN). The proposed algorithm segments spectrograms into image patches and represents graphs through connections between adjacent image patches. Subsequently, Graph Convolutional Network (GCN) is trained using the represented graphs to classify signals. In experiments with publicly available underwater acoustic data, the proposed algorithm represents the line frequency features of spectrograms in graph form, achieving an impressive classification accuracy of 92.50 %. This result demonstrates a 8.15 % higher classification accuracy compared to conventional Convolutional Neural Network (CNN).

• ETRI Journal
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• v.46 no.1
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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.

• Speech Sciences
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• v.11 no.3
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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.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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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.

• Journal of the Korea Convergence Society
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• v.10 no.9
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• pp.193-198
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• 2019

This study analyzed the changes of vowel formant, voice intensity, and fundamental frequency of vowels for 11 months using acoustochemical spectrogram analysis of women diagnosed with amyotrophic lateral sclerosis (ALS). The test word was a vowel /a, i, u/ and a diphthong /h + ja + da/, /h + wi + da/, and /h +ɰi+ da/. Speech data were collected through the word reading task presented on the monitor using 'Alvin' program, and the recording environment was set to 5,500 Hz for the nyquist frequency and 11,000 Hz for the sampling rate. The records were analyzed by using spectrograms to vowel formants, voice intensity, and fundamental frequency. As a result of analysis, the fundamental frequency and intensity of the ALS process were decreased and the formant slope of the diphthong was decreased rather than the formant change in the vowel. This result suggests that the vowel distortion of ALS due to disease progression is due to the decrease of tongue and jaw co morbidity.

• Animal Systematics, Evolution and Diversity
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• v.29 no.4
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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.

• Speech Sciences
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• v.12 no.2
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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/.

• Speech Sciences
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• v.10 no.2
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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.