• Speech Sciences
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• v.9 no.3
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• pp.3-16
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• 2002

We examined some problems in speaker identification procedures: transformation of acoustic parameters into auditory scales, invalid measurement values, and comparability of spectral energy values across the frequency range. To resolve those problems, we analyzed the acoustic spectral energy of three Korean numbers produced by ten female students from narrow-band spectrograms at 19 proportional time points of each voiced segment. Then, cells of the first five spectral matrices were averaged to form a matrix model for each speaker. The correlation coefficients and sum of the absolute amplitude difference in each pair of the spectral models of the ten subjects were obtained. Also, some individual matrix models were compared to those of the same subject or the other subject with a similar spectral model. Results showed that in numbers '2' and '9' subjects could not be clearly distinguished from the others but in number '4' it shed some possibility of setting threshold values for speaker identification if we employed the coefficients and the sum of absolute difference. Further studies would be desirable on various combinations of the range of long-term average spectra and the degree of signal pre-emphasis.

• Journal of Computing Science and Engineering
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• v.7 no.2
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• pp.112-121
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• 2013

The last years have seen a rise of interest in using electroencephalography-based brain computer interfacing methodology for investigating non-medical questions, beyond the purpose of communication and control. One of these novel applications is to examine how signal quality is being processed neurally, which is of particular interest for industry, besides providing neuroscientific insights. As for most behavioral experiments in the neurosciences, the assessment of a given stimulus by a subject is required. Based on an EEG study on speech quality of phonemes, we will first discuss the information contained in the neural correlate of this judgement. Typically, this is done by analyzing the data along behavioral responses/labels. However, participants in such complex experiments often guess at the threshold of perception. This leads to labels that are only partly correct, and oftentimes random, which is a problematic scenario for using supervised learning. Therefore, we propose a novel supervised-unsupervised learning scheme, which aims to differentiate true labels from random ones in a data-driven way. We show that this approach provides a more crisp view of the brain states that experimenters are looking for, besides discovering additional brain states to which the classical analysis is blind.

• Phonetics and Speech Sciences
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• v.8 no.2
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• pp.73-80
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• 2016

The purpose of this study was to analyze perceptual and spectral/cepstral measurements in patients with adductor spasmodic dysphonia(ADSD). Sixty participants with gender and age matched individuals(30 ADSD and 30 controls) were recorded in reading a sentence and sustained the vowel /a/. Acoustic data were analyzed acoustically by measuring CPP, L/H ratio, mean CPP F0 and CSID, and auditory-perceptual ratings were measured using GRBAS. The main results can be summarized as below: (a) the CSID for the connected speech was significantly higher than for the sustained vowel (b) the G, R and S for the connected speech were significantly higher than for the sustained vowel (c) Spectral/cepstral parameters were significantly correlated with the perceptual parameters, and (d) the ROC analysis showed that the threshold of 13.491 for the CSID achieved a good classification for ADSD, with 86.7% sensitivity and 96.7% specificity. Spectral and cepstral analysis for the connected speech is especially meaningful on cases where perceptual analysis and clinical evaluation alone are insufficient.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1987.05a
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• pp.9.1-9
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• 1987

뇌간유발청력검사는 최근 들어 신생아 및 영유아에 있어 청력 및 청신경로의 성숙(auditory maturation)정도를 파악할 수 있는 객관적인 진단 방법으로 평가되고 있다. 그러나 상기 검사결과는 측정계기의 종류 및 측정방법에 따라 다소 차이를 보일 수 있다. 우리나라에서는 아직 정상 신생아를 대상으로 뇌간유발청력검사에 대한 보고가 없는 실정이다. 이에 본 교실에서는 87년 3~4월에 Severance병원에서 출생한 정상 신생아 20명을 대상으로, 출생 후 16내지 69 시간내 두 차례에 걸쳐 뇌간유발 전달시간 및 뇌간유발 역치를 측정, 다음과 같은 결과를 얻었기에 보고하는 바이다. 1) 72.5 ㏈, 4KHz click에 대한 평균 절대적 latency는 각각 I(1.68), II(2.74), III(4.33), IV(5.71), V(6.77), Ⅵ(8.16), Ⅶ(9.85)였고 tone pip은 각각 I(2.04), II(3.04), III(4.60), IV(5.75), V(7.14), Ⅵ(8.54), Ⅶ(10.60) 이었다. 2) 평균 뇌간전위 유발역치는 29.5㏈ SPL 이었다. 3) 파형은 A형이 1.7%, 3형이 30.2%, C형이 45.7%, D형이 5.2%, E형이 1.7%, F형이 15.5%이었고, click과 tone pip, 자극음의 강도, ISI에 따른 차이가 없었다. 4) 제1소파에서 제5소파까지의 절대적 latency와 I- III, III-V,및 I-V의 상대적 latency에 있어서, 반복율, 자극음 종류 및 첫째날과 둘째날의 비교치에 있어서만이 선택적으로 유의한 차이가 발생하였으며, 자극음의 크기에는 차이가 나타나지 않았다.

• Journal of Ginseng Research
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• v.34 no.4
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• pp.336-341
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• 2010

One mechanism of inner ear damage by noise-induced hearing loss (NIHL) is the production of reactive oxygen species (ROS). Because Korean red ginseng (KRG) has an anti-ROS effect in various tissues, KRG may have a role in preventing NIHL. A window period exists in which ROS formations continue after noise exposure, and further damage can be prevented by antioxidants. In this study, we aimed to investigate the effects of KRG after exposure to noise. KRG (200 mg/kg) was fed to mice for 3 days after noise exposure. The change in hearing level was analyzed by measuring the auditory brainstem response. To induce a temporary threshold shift (TTS) of hearing, mice were exposed to 110 dB white noise for 3 hours. Fast recovery of hearing was observed in mice fed KRG 1 hour and 1 day after noise exposure for 3 days. The expression of 8-oxoguanine was not observed in the inner ears of mice fed KRG 1 hour after noise exposure, but was evident in the stria vascularis of mice in the control group (noise exposure only). From this study, we conclude that KRG acted as an effective inhibitor of NIHL in TTS cases.

• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.273-279
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• 2012

In this thesis, a nonlinear compression fitting method was studied for each frequency channel of a 64 channel digital hearing aid. Unlike conventional fitting formula method done from the result of the hearing loss test, the present fitting method uses the auditory threshold of sound pressure measured near the tympanic membrane while ITE (In-The-Ear) hearing aid is fitted into the user's ear canal. Also, the spectral distribution of the voice sound pressure was used for realizing of output sound pressure compression curves against input sound pressure level. Theoretical research results of FFT-iFFT compression algorithm has been evaluated by experimental gain measurements at each different input sound pressure level 50 dB, 70 dB, 90 dB respectively.

• The Journal of the Acoustical Society of Korea
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• v.24 no.6
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• pp.353-357
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• 2005

Declining auditory performance with advanced age is a well known and common problem that is becoming more Prevalent due to the increasing number of elderly people in our society. We introduce a novel ARCISM (Audiogram Result Computer Input. Save & Management software) data management program which enables the assessment of the risk of past history of hearing impairment on the basis of known risk factors. This study investigates the reference levels of pure tone hearing threshold of normal aging in Korean and the difference between fenders. The subjects were carefully selected by questionnaire and absence of any history of otologic infection, noise exposure. and ototoxic drug among 1603 subjects. who visited Health Promotion Center in Daegu Fatima Hospital for one year. The results show (1) hearing sensitivity declines with age. (2) higher frequency shows steeper slope of hearing declines than lower frequency. and (3) there were more hearing loss at 4 and 8 kHz in men than in women. Due to the ARCISM program. it was possible to manage huge data of hearing results and to obtain the reference level of a9e-related hearing declines. Furthermore, we expect that the results of this study can be the fundamental data for hearing rehabilitation for the elderly and for developing suitable hearing aids for Korean.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.17.1-17
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• 1982

In 1965, Rosenberg reported that platinum compounds not only inhibit growth and cell division of E. coli but also has anti-tumor activity. Since then, through animal and clinical experiments by Welsch(1971), Speer(1972), Rossof(1972), Hill(1974), and Wittes(1975), it was proved that Cis-platinum has excellent supressive effects on malignant tumor, especially on head and neck cancer. Accordingly, Cis-platinum is now widely used, sometimes without any other durg, or sometimes with Bleomycin and Methotrexate etc. Inspite of the strong anticancer effect, the use of Cis-platinum is quite often discouraged because of the reports that Cis-platinum causes auditory impairment at high frequencies above the speech range due to inner ear damage and irreversible change in the renal tubules. Since Kohonen et al(1965), Standnicki et al(1974) reported that Cisplatinum has toxic effects at the basal turn of the cochlea using guinea pig, many studies on ototoxicity after infusion of Cis-platinum have been carried out using animals. But the studies on ototoxicity in human beings can hardly be found except in reports by Piel et al(1974) and Hong et al (1979). So the authors did a study which tried to clarify the ototoxic effect by comparing the hearing level after infusion of Cis-plastinum with the hearing level before infusion of Cis-plastinum in 30 patients who was treated with Cis-platinum and admitted to the dept. of otolaryngology of Yonsei University Hospital during 2 years and a half from July. 1979 to March. 1982 and the following results were obtained. 1) The results of auditory evaluation, using the pure tone average, hearing loss of 4kHz and 8kHz, Speech Reception Threshold, PB score, SISI showed that the difference of dosage does not change the hearing level after infusion of Cis-platinum and before infusion of Cis-platinum. 2) Cis-platinum had no effect on the hearing level of patients with conductive hearing loss, or with sensorineural hearing loss, as well as with normal hearing level. 3) The infusion of Cis-platinum did not cause any change in creatinine clearance, creatinine, uric acid, but only one case showed that Cis-platinum caused severe nephrotoxicity. 4) The infusion of Cis-plastinum did not cause any change in hemoglobin, leukocyte count, platelet count and there was no correlation with the amount of infusion. 5) To see the side effect of hydration practiced with the infusion of Cis-platinum, the electrolytes, particularly the K level in the serum was measured. But the results did not show any change. 6) Judging from the results of this study mentioned above, ototoxicity caused by infusion of Cis-platinum can be prevented by sufficient hydration. Also the results might say that the appropriate method of infusion of Cis-platinum might be effective in the patients with head and neck cancer who had sensorineural hearing loss for whom the infusion of Cis-platinum has been absolutely cotraindicated.

• Journal of agricultural medicine and community health
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• v.48 no.1
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• pp.41-49
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• 2023

Objectives: To obtain audiologic basic data to diagnose the noise induced hearing loss of workers in fisheries. Methods: The charts of the referred fishermen with noise induced hearing loss from November 2022 to February 2023 at a general hospital were retrospectively reviewed. Pure tone audiometry, speech audiometry, auditory brainstem response test and auditory steady state response test were conducted. Results: All of them were men over 60 years of age, and the average duration of exposure to noise was 38.9 ± 10.8 years, and the average symptom duration of hearing loss was 13.4 ± 4.3 years. Although the hearing thresholds in the high frequencies were higher than thresholds in the low frequencies, the audiogram showed a down-sloping pattern without rebound at 8 kHz. 10.5% of the cases had thresholds greater than 75 dB in high frequencies, but 57.9% had thresholds greater than 40 dB in low frequencies. Other hearing test results of fishermen were similar to those of general noise-induced hearing loss. Conclusions: Although the fishermen were exposed to noise for a long time, they recognized hearing loss late. The hearing threshold in lower frequencies of the fishermen was higher than expected. Further studies will be needed to analyze the audiologic characteristics of noise-induced hearing loss of the fishermen after confirming noise exposure by conducting a survey on the working environment, such as the noise level and working hours.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.89-93
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• 2009

Purpose: To purpose of this study was the pure-tone audimetry changes to compare pre and post fogging after visual correction in normally hearing adults. Methods: The estimated that no ocular and audiolar disesases, we selected (male: 30, female: 20) in corrected visual acuity over the 1.0 eye. Pre and post fogging were measured using the pure-tone audimetry. Results: To compared fre and post fogging, fre fogging was higher than fre fogging. The take value were just about every kind of Hz but 200 Hz, respectively which were statistically significant (p<.05). Low Hz area in 250 and 500 Hz were 6.8${\pm}$8.4dBHL, 4.3${\pm}$6.6dBHL, there is not all the difference between any other area, 2000 Hz in the middle Hz area was 0.8${\pm}$4.5dBHL. Conclusions: The study presents different results of measurements in within normal limits. we thought that pure-tone thresholds to the pre and post fogging after refractive correction in normal adults and would be used basic data.