• 한국전산구조공학회논문집
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• 제28권2호
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• pp.139-144
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• 2015

현재 방음을 위해 사용되는 흡음구조는 흡음률이 높은 재료를 이용하여 만들어진 판을 방음이 필요한 벽에 붙이거나 삽입하는 형상이다. 이러한 형상은 흡음재의 재료가 고정되기 때문에, 사용하는 환경에 따라 효율성이 변화한다는 한계점이 있다. 하지만, 흡음재 없이 흡음효과가 나타나도록 외벽의 구조를 설계한다면, 흡음재의 재료에 대한 제한이 없어져 가용 범위가 상당히 넓어지게 된다. 따라서 우리는 이러한 효율적인 외벽의 구조로서 타공판의 구조를 제안한다. 타공판이 어떻게 흡음률을 가지는 지에 대해 등가물성치를 이용한 수치해석을 통하여 검증하였다. 또한 타공판의 형상과 공명기의 형상이 유사함을 밝혀내었고, 이를 토대로 타공판이 갖는 흡음구조에 대해 분석하였다. 결과적으로 타공판은 별도의 흡음재가 없더라도 효율적인 흡음효과를 낸다는 것을 확인할 수 있었다. 또한 사용자가 타공판의 형상을 쉽게 변화시킴으로서, 특정한 주파수의 소음을 차단할 수 있어 상당히 효율적인 흡음구조임을 확인하였다. 본 연규의 결과들은 향후 자동차, 고속철도, 주택 외벽 등에 사용되는 흡음구조로서 사용될 수 있을 것이며, 나아가 흡음구조를 설계하는데 기본적인 도구가 될 수 있을 것이다.

• 대한후두음성언어의학회지
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• 제8권2호
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• pp.161-165
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• 1997

Background : The rhinomanometry and acoustic rhinometry can assess e nasal passage dynamically and statically Recently, analytic methods such as nasometer and sound spectrogram are gaining wide attention to evaluate the nasality objectively. Objectives : firstly to determine if ere was a relationship between the new methods and nasal airway resistance, and secondly to establish if the measurement of nasalance and sound spectrum could be used as an alternative to rhinomanometry and acoustic rhinometry. Materials and Methods : Thirty two patients who underwent either septoplasty and turbinectomy for nasal obstruction were studied. And their ages ranged form 15 to 45 years, with an average of 26.1 years. The rhinomanometry, nasometer, sound spectrogram were performed at preoperative and postoperative 4 weeks day. Results : After operation, subjective symptoms and rhinomanometric results were significantly improved but nasalance and slope of nana, mama and mamma passage had not meningful change. The significnat changes were noted in nasalance and first nasal formant frequency of nasal consonant of velum(angang). Conclusion : Nasometer and sound spectrogram had a limitation for the measure of nasal patency.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.631-640
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• 2020

In this study, the effect of specimen size and layer thickness on the sound absorption of the leaves of two evergreen broad-leaved tree species, Dendropanax morbiferus and Fatsia japonica, was investigated. The specimen sizes of 0.5 × 0.5, 1.0 × 1.0, and 2.0 × 2.0 ㎠ and layer thicknesses of 1.00, 1.75, and 2.50 cm were considered. At the layer thickness of 2.5 cm, the leaf of the D. morbiferus showed no significant difference in sound absorption coefficients (SACs) as the sample size varied, however, a significant change in SACs was recorded in that of the F. japonica. At 1.0-cm thickness, the SACs of the F. japonica leaf varied more remarkably with the sample size. The 2.50-cm-thick F. japonica leaf with the specimen size 0.5 × 0.5 ㎠ exhibited the highest sound absorption effect among all samples investigated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.645-648
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• 2005

The grounds of multipurpose practical use degree are built much holding world cup 2002 but material that is used in this building most external membrane ceiling is accomplishing PTEE A master and servant. Therefore, this research analyzed assessment about sound absorption special quality that measure ventilation quantitys of 10 act material and analyze correlation with Air Permeability and the sound absorption rate, and follow in change of layer of air of inside facts material. Result is as following. When Air Permeability good dimension is 5$\sim$15 cc/cm$^2$/sec and acoustic absorptivity is the best as Air Permeability result that measure acoustic absorptivity of inside facts material particularly firstly, could know 8$\sim$9 cc/cm$^2$/sec love. When establish sound absorption inside facts in external membrane as result that measure acoustic absorptivity of inside (acts material secondly, could know that acoustic absorptivity is good though become about minimum back layer of air 900mm.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.759-764
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• 2000

The accurate prediction of aeroacoustic analysis is necessary for designers to control and reduce airflow-induced sound pressure levels in high speed rotating DVD drives. This paper focuses on the numerical prediction of airflow-induced sound in DVD drives. Computational fluid dynamics(CFD) is first conducted to evaluate flow field characteristics due to the high-speed disk rotation, and to support the acoustic analysis. The acoustic analogy based on Ffowcs Williams-Hawkings(FW-H) equation is adopted to predict aeroacoustic noise patterns. The integral solution for quadrupole volume source is included to identify the turbulence noise generated inside the DVD tray. The strength of sound pressure level with respect to rotating speed is discussed to meet upfront demand on the high fidelity product development. The present study also focuses on the noise directivity and examines how much the sound noise is sensitive to change in rotating speed. Near-field noise is strongly affected by the flow field characteristic, which is caused by the complex shape of the tray. For a mid-field, the quadrupole noise play as a counterpart of thickness noise or loading noise, so it generates different sound noise patterns compared with those in the near field.

• 대한후두음성언어의학회지
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• 제33권2호
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• pp.77-82
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• 2022

Hunminjeongeum was made by the Great King Sejong, and composed of 17 consonant and 11 vowel letters. All the 28 letters were made according to the shape of vocal organ or space at the point of articulation for each letters. This review article focused on phonetic and phoniatric consideration for explanation of the designs of the middle vowel letters, especially three main vowel letters [ • (天, heaven), ㅡ (地, earth), ㅣ (人, human)] using video-fluoroscopic evaluation as well as computed tomography scanning, etc. During articulating / • / sound, a ball-like space at frontal portion of the oral cavity was found, tongue was contracted, and sound was deep (舌縮而聲深). During /ㅡ/ sound, a flat air space between oral tongue and hard palate was created. Tongue was slightly contacted neither deep nor shallow (舌小縮而聲不深不淺). During /ㅣ/ sound, tongue was not contacted and Sound is light (舌不縮而聲淺). Tongue was moved forward making longitudinal oro-pharyngeal air space. So, I'd like to suggest that we had better change the explanation drawing from a philosophical modeling to a more scientific modeling from real vocal tract space modeling during articulating middle vowels of Hunminjeongeum.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.809-812
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• 2006

This article shows the study on the arresting sound occurrence due to the interaction of the centrifugal Fan and bellmouth suction flow with bellmouth height as variable. It has accomplished to measure of inlet noise and also to analysis suction pressure distribution through experiment and also using CFD. The main cause of sound occurrence was judged with the effect due to static pressure change of bellmouth surface.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제15권4호
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• pp.239-252
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• 1993

This study was done to analyze phonetic dysfunction and the effect of orthognathic surgery to phonation in the patients of mandibular prognathism. 20 persons were chosen as normal group and 20 patients of mandibular prognathism as abnormal for this study. 5 vowel sounds-'ㅏ(a)', 'ㅔ(e)', 'ㅣ(i)', 'ㅗ(o)', 'ㅜ(u)' and 14 consonant sounds-'ㄱ(g)', "ㄴ(n), 'ㄷ(d)', 'ㄹ(l)', 'ㅁ(m)', 'ㅂ(b)', 'ㅅ(s)', 'ㅇ(ng)', 'ㅈ(j)', 'ㅊ(ch)', 'ㅋ(k)', 'ㅌ(t)', 'ㅍ(p)', 'ㅎ(h)', were checked. We recorded these sounds in the period of preopration, postop. 12 months, postop. 24 months. A Formant ratio and a length of consonant time were studied with discriminant analysis. As a result of the study, the following conclusion were gained. 1. As a result of the analysis on vowel dysfunction patiensts of mandibular prognathism, more than 80% of men patients showed the dysfunction in prelingual sound 'ㅔ(e)' and 'ㅣ(i)'. More than 70% of women patients showed the dysfunction in all vowel. 2. One year later from the orthognathic surgery, men patients showed a marked improvement in 'ㅏ(a)'. The next were 'ㅗ(o)', 'ㅜ(u)' and 'ㅣ(i)'. Women patients showed a marked improvement in 'ㅜ(u)'. 3. Two year later from the orthognathic surgery, men patients showed a marked improvement in prelingual sound 'ㅔ(e)' and postlingual sound 'ㅗ(o)'. Women patients showed a marked improvement in 'ㅏ(a)'. More than 20% of patients showed the phonetic improvement compared with the condition of the postop. 12 months. 4. As a result of the analysis on consonant dysfunction patient of mandibular prognathism. more than 80% of men patients showed the dysfunction in lingual sound 'ㅅ(s)'. Most women patients showed the dysfunction in labial sound 'ㅁ(m)' and lingual sound 'ㄴ(n)'. More than 50% of patients showed the dysfunction in labial sound and lingual sound. 5. One year later from the orthognathic surgery. men patients showed a complete improvement in hard palatal sound 'ㅈ(j)'. The next were labial sound 'ㅂ(b)', lingual sound 'ㅅ(s)', soft palatal sound 'ㄱ(g)' and 'ㅋ(k)'. Women patients showed a marked improvement in soft palatal sound 'ㅇ(ng)' and 'ㄱ(g)'. 6. Two year later from the orthognathic surgery, all patients showed remarkable improvement in consonant sounds. except for labial sound 'ㅁ(m)', 'ㅍ(p)' and lingual sound 'ㄴ(n)'. The improvement ratio was increased as the time was going on compared with the condition of postop 12 months.

• 한국산학기술학회논문지
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• 제10권6호
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• pp.1201-1206
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• 2009

음상의 거리정위에 있어서 중요한 물리적 요인으로는 알려진 음압레벨, 반사음, 양 귀간 차, 음원의 종류, 머리전달함수(HRTF) 등의 여러 요인들이 중요한 판단 자료로 이용되어진다고 알려져 있다. 본 논문에서는 거리판단에 사용되어지는 물리적 요인 중 음압레벨의 크기가 거리정위에 미치는 영향을 알아보기 위해 반사음이 존재하지 않은 무향실에서 음원의 출력 음압레벨을 일정한 경우와 귀 입력 음압레벨을 일정하게 한 경우에 대하여 청취실험을 통해 거리판단에 있어서 음압레벨의 영향에 대하여 고찰했다. 그 결과. 음원출력 음압레벨을 일정하게 한 경우와 귀 입력 음압레벨을 일정하게 한 청취실험에 있어서 제시한 음원거리보다 지각한 음상거리를 가깝게 정위하는 경향이 있다는 것이 관찰되었다. 또, 귀 입력 음압레벨이 일정한 경우에는 약 2m 정도까지의 거리에서는 실제 제시한 음원거리의 증가에 따라 지각한 음상의 거리가 음원거리에 대응하여 증가하지만, 그 이상의 거리에서는 음원거리의 증가에 따라 지각한 음상거리가 증가가 거의 없음을 알 수 있었다. 반면 음원출력 음압레벨이 일정한 경우에는 지각한 음상거리가 귀 입력 음압레벨이 일정한 경우보다 보다 더 먼 3m 정도의 거리까지 증가하고 있음을 알 수 있었다. 이와 같은 청취실험 결과로부터 반사음이 존재하지 않은 조건에서의 음상의 거리정위에는 음압레벨이 거리판단의 중요한 요소로 작용하고 있음이 확인되었다.

• Fibers and Polymers
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• 제7권4호
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• pp.450-456
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• 2006

The objectives of this study were to investigate physiological and psychological responses to the rustling sound of Korean traditional silk fabrics and to figure out objective measurements such as sound parameters and mechanical properties determining the human responses. Five different traditional silk fabrics were selected by cluster analysis and their sound characteristics were observed in terms of FFT spectra and some calculated sound parameters including level pressure of total sound (LPT), Zwicker's psychoacoustic parameters - loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z), and sound color factors such as ${\Delta}L\;and\;{\Delta}f$. As physiological signals, the ratio of low frequency to high frequency (LF/HF) from the power spectrum of heart rate variability, pulse volume (PV), heart rate (HR), and skin conductance level (SCL) evoked by the fabric sounds were measured from thirty participants. Also, seven aspects of psychological state including softness, loudness, sharpness, roughness, clearness, highness, and pleasantness were evaluated when each sound was presented. The traditional silk fabric sounds were likely to be felt as soft and pleasant rather than clear and high, which seemed to evoke less change of both LF/HF and SCL indicating a negative sensation than other fabrics previously reported. As fluctuation strength(Z) were higher and bending rigidity (B) values lower, the fabrics tended to be perceived as sounding softer, which resulted in increase of PV changes. The higher LPT was concerned with higher rating for subjective loudness so that HR was more increased. Also, compression linearity (LC) affected subjective pleasantness positively, which caused less changes of HR. Therefore, we concluded that such objective measurements as LPT, fluctuation strength(Z), bending rigidity (B), and compression linearity (LC) were significant factors affecting physiological and psychological responses to the sounds of Korean traditional silk fabrics.