• 문화기술의 융합
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• 제7권1호
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• pp.570-575
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• 2021

인간은 오감을 풍요롭게 느끼면서 생활하기 때문에 인간의 행복한 삶을 영위하기 위해서는 청력이 손상되지 않도록 주의하여야 한다. 생활환경에서 입게 되는 청력손상은 특정 주파수대역이 먼저 손상되는 부분대역에서 청력손상이 일반적이다. 그러나 청력손상의 초기 통증이 별로 나타나지 않아서 그 증세를 초기단계에는 알아내기가 어렵다. 본 연구에서는 간단한 어플 등을 통해 손쉽고 빠르게 청력손상을 자가 측정할 수 있는 고속 측정법을 제안하였다. 이 방법은 voice soub-band별 이득 보상된 pure tone 9개를 번갈아 양쪽 귀에 들려줌으로써 자신의 청력손상을 스스로 고속 판별하게 된다. 1인당 27초 동안 18번의 톤 펄스를 들려주었을 때, 12명의 피험자들 중에서 1명이 부분청력손상 의심자로 확인되었다. 그리고 피험자들에게 들린 횟수 청력판별법을 알려주니, 실험참가자들 스스로가 자신의 청력손상여부를 바로 판별해 내었다. 이러한 측정방법은 스마트 폰으로 27초 내에 양쪽 귀의 청력을 간단히 판단함으로서 병원에서는 10분 이상 소요되었던 청력측정이 비교적 정확하게 이루어져서, 시간과 비용을 줄이면서 청력건강을 유지할 수 있음을 파악하였다.

• 대한소아치과학회지
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• 제50권3호
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• pp.239-251
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• 2023

이 연구는 소음이 유발되는 진료 시 노이즈 필터링 기능이 있는 이어플러그를 착용하고 업무를 시행하여 노이즈 필터링 이어플러그가 치과의사의 청력에 미칠 수 있는 영향에 대해 조사하였다. 연구 대상자의 청력을 평가하기 위해 순음 청력 검사와 변조이음향방사 검사를 첫 내원 시와 1년 후 측정하였다. 연구 결과, 이어플러그를 착용하지 않은 군에 비해 이어플러그를 착용한 군의 순음 청력 역치 평균값이 유의미하게 감소하여 청력이 호전되는 모습을 보였다. 그러나 변조이음향검사의 신호대잡음비는 유의미한 차이를 보이지 않았다. 이러한 결과는 노이즈 필터링 이어플러그가 청력 손실을 예방하는 데 일부 효과적일 수 있다는 것을 보여준다. 그러나 1년간의 관찰 기간은 청력 변화를 충분히 확인하기에 어려울 수 있으므로, 추적 기간을 늘린 후속 연구가 필요할 것으로 보인다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.543-543
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• 2010

The objective of this research is estimating the location of interested sound source by using the similarity between a beamformer output in time domain and the candidate signal. The waveform of beamformer output at the location of sound source is similar with the waveform emitted by that source. To estimate the location of sound source by using this feature, we define quantified similarity between candidate signal and beamformer output. The candidate signal describes the signal which is generated by interested source. In this paper, similarity is defined by four methods. The two methods use time vector comparison, and the other two methods use time-frequency map or linear prediction coefficients. To figure out the results and performance of localization by using similarities, we demonstrate two conditions. The one is when two pure tone sources exist and the other condition is when several bird sounds exist. As a consequence, inner product with two time-vectors and structural similarity with spectrograms can estimate the locations of interest sound source.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.202-205
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• 2004

This paper represents the role of pinna in localizing target direction. Specially, this paper described what is the role of right-side pinna versus left-side pinna. In this experiment, one side of the pinna function was distorted intentionally by inserting a short tube on the ear canal. The localization error caused by right and left side pinna distortion was investigated. Since a laser pointer showed much less error (0.5%) in localizing target position than FASTRAK (30%) that has been generally used, it was used for the pointing task. It was found that harmonic components were not essential for the auditory target localization, however, non-harmonic nearby frequency components were more important to localize target direction of sound. We have found that the right pinna is one of the most important functions in localizing target direction and pure tone with only one frequency component is confusing for localization.

• 대한의용생체공학회:의공학회지
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• 제30권1호
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• pp.94-102
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• 2009

In this paper, we propose a hearing impairment simulator considering reduced frequency selectivity of the hearing impaired, and verify it's performance through experiments. The reduced frequency selectivity was embodied by spectral smearing using linear prediction coding(LPC). The experiments are composed of 4 kinds of tests; pure tone test, speech reception threshold(SRT) test, and word recognition score(WRS) test without spectral smearing and with spectral smearing. The experiments of the hearing impairment simulator were performed with 9 subjects who have normal hearing. The amount of spectral smearing was controlled by LPC order. The percentile score of WRS test without smearing is $89.78{\pm}2.420%$. The scores of WRS with 24th LPC order and with 8th LPC order are $88.00{\pm}3.556%$ and $83.78{\pm}2.123%$ respectively. It is verified that WRS score is lowered by decreasing LPC order. This is a reasonable result considering that spectral smearing is getting heavier according to decreasing LPC order. It is confirmed that spectral smearing using LPC simulates the reduced frequency selectivity of the hearing impaired and affects the clearness of speech reception.

• 복식
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• 제52권6호
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• pp.41-50
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• 2002

The purpose of this study is to classify korean clothing image using brainstorming method. Brainstorming theme is selected 'The Land of Morning Calm 'which famed to foreigner about Korea. Brainstorming members were 10 persons for 1st. 9 persons for End. The 119 words of association from 'morning calm'were to extracted at 1st brainstorming. The group of senses image were to classified at End brainstorming. The results of this study were as follows : 1. The clothing image type of tactual sense implied feeling of that downy bedding in a soft spring and grandmother's hands as warm. rough. 2. The clothing image type of smelling sense associated smells of pleasant. mild. and fresh. 3. The clothing image type of auditive sense consisted mainly sense of indirect. resonance. small, and clear sounds. 4. The clothing image type of visual sense associated pure, passive, gentle, and lasting life-force as weeds and wild flowers. Korean line is pointless and rounded curve. Korean form is soft silhouette as streamy, not exaggerate and wavy detail of slim and short. Korean color is not dyed, just natural color and pastel tone. Korean textile is a natural material as linen, ramie. and coarse silk.

• 한국산업보건학회지
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• 제20권2호
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• pp.94-101
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• 2010

This study was performed to examine the asymmetry of hearing loss among the noise exposed male workers. Findings of otoscopic examination, pure tone audiometry and tympanometry were evaluated for 179 male workers working in the noise exposed workplace. And also selfadministered structured questionnaires were used for each worker's work-related and general characteristics including personal health behaviors. There were significant differences of hearing threshold between right and left ears at 1,000 Hz and 3,000 Hz(p<0.05). And also significant differences of hearing threshold were noted in the age group over 50 at 3,000 Hz, the high risk drinking group either at 3,000 Hz and 4,000 Hz, the work duration group 10-19 years at 3,000 Hz, the noise exposure group under 90 dB(A) at 3,000 Hz, the noise exposure group over 90 dB(A) at 1,000 Hz, the non-wearing protective device group at 4,000 Hz, and the wearing protective device group at 3,000 Hz(p<0.05). Further study is needed to explore the extent and the related factors of the asymmetry of hearing loss in the general population and occupationally noise exposed group.

• 소음진동
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• 제7권1호
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• pp.71-79
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• 1997

The objective of this study is to investigate experimentally the effect of surface conditions of the plate on the impinging jet noise. The experimental results about the spectrum, the sound pressure level and the directivity are pressented and discussed in relation with the surface conditions. Regardless of the surface conditions, the pure tones of high level are generated at the same frequency band and the overall sound power level of impinging jets is much higher than that of the free jet. However, the velocity dependence of the sound pressure level and the directivity are different between smooth surfaces and rough surfaces. The dependence of sound pressure level on the jet velocity shows that the smooth surface generates quadrupole-type sound like free jets. However, the perforated or the rough surface radiates sound power exactly proportional to the sixth power of the jet velocity, indicating that the source is fixed dipole type. The directivities of 1/3 octave band sound pressure level for both the free and impinging jet show the peak directivity at 115$^\circ$ upstream, probably due to the refraction associated with velocity gradient.

• The Journal of the Acoustical Society of Korea
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• 제22권2E호
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• pp.78-86
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• 2003

We analyzed the measured acoustic field to explore the characteristics of a horizontal coherence in shallow water. Signal spatial coherence data were obtained in the continental shelf off the east coast of Korea using a horizontal line array. The array was deployed on the bottom of 130 m water depth and a sound source was towed at 26 m depth in the source-receiver ranges of 1-13 ㎞. The source transmitted 200 ㎐ pure tone. Topography and temperature profiles along the source track were measured to investigate the relationship between the horizontal coherence and environment variations. The beam bearing disturbance and array signal gain degradation is examined as parameters of horizontal coherence. The results show that the bearing disturbance is about ± 8° and seems to be affected by temporal variations of temperature caused by internal waves. The array signal gains show degradation more than 5㏈ by the temporal and spatial variations of temperature and by the down-sloped topography.

• 한국소음진동공학회논문집
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• 제17권8호
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• pp.736-740
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• 2007

A laboratory study on low frequency noise assessment has been carried out to evaluate the relevance of the weighting curve. Especially, the A-weighting curve which is used in most noise assessments has been evaluated using the acceptability limit in this study. The acceptability limit is one of the indicators in which the subjective responses were well-reflected. For the measurement of the acceptability limit, pure tone stimuli were used in the frequency range between 20 and 200 Hz. The measurement was proceeded in the anechoic chamber to minimize the background noise level. A total of 29 test subjects, who were aged between 19 to 33 years, participated in this study. They had been exposed to various stimuli for about 1 hour by supra-aural earphone. The measurement consisted of two listening sessions: hearing threshold and the acceptability limit session. The results showed that the tendency of the acceptability limit curve was approximately equal to C-weighting curve which had been found to be superior to A-weighting curve in assessment of low frequencies.