• 한국의류학회지
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• 제6권1호
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• pp.61-66
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• 1982

Succeeding to Report 1, to compare folded curtain fabrics with curtain fabrics, the sound pressure level (SPL) of folded curtain fabrics were measured by sound level meter. Transmission coefficient was calculated by the ratio of incidence sound intensity and transmission sound intensity. The relationship between these values and factors (drape coefficient, porosity) relating to the structure of curtain fabrics were investigated experimentally. The following results were obtained: 1. The transmission coefficient by ratio of sound pressure level was lower than that by ratio of sound intensity. 2. In folded curtain fabrics, difference of SPL was smaller and transmission coefficient generally decreased. 3. The relation between the porosity and transmission coefficient of curtain fabrics is given as plus correlation.

• 대한치과보철학회지
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• 제26권1호
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• pp.31-49
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• 1988

This study was performed to investigate the sound distortion following the alternation of the palatal plate thickness, for this study, 3 subjects who were born in Seoul and spoke Seoul dialect were recruited from K university male student population. First, their sounds of /아(a)/, 어(e)/, 오(o)/, 우(u)/, 으($\.{+}$), 이(i)/,에(e)/ without inserting plate were recorded , and then the sounds with palatal plates of different thickness were recorded, respectively. The palatal plates was constructed to cover the alveolar & palatal surfaces of the maxilla with an approximate thickness of 1.0mm, 2.5mm, and thickness of 2.5mm over the alveolar ridge & 1.0mm elsewhere and, named B, C, D-type, in succession. Series of analysis were administered through Computer (16 bit IBM PC/AT) at analyze the sound distortions. These experiments were analyzed by the LPC, Log Area Ratio. The findings led to the following conclusions: 1. Sound distortions were relatively minute in each condition and informations, however, /이(i)/ was the most distorted vowel in all conditions. 2. By and large, sound distortion was large in C, D-types. However, there was no correlation of the distortion rate on the 3 informants, and all tested vowels. 3. It was similar to LPC, Log Area Ratio distortion rates. 4. It was found that the sound distortion wit]1 plate inserted was verified to the numeric value with LPC and Log Area Ratio method.

• 대한치과보철학회지
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• 제31권1호
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• pp.39-50
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• 1993

The purpose of this study was to investigate the association between characteristics of temporomandibular joint sound and possible contributing factors of temporomandibular joint sound. 1487 high school students (798 men and 689 women) aged from 16 to 18 were asked by questionnaires which was made for this study by T.M.J. clinic, dental infirmary, School of Dentistry, Chosun University, and data obtained from questionnaires were analyzed by chi-square test. The following results were obtained: 1. The prevalence of temporomandibular joint sound were found in 35.7% of all the subjects. 2. Temporomandibular joint sound could be unchanged, reduced and increased frequencey over time dependent on the individual. 3. The intensity of temporomandibular joint sound could be unchanged and increased during the chewing of hard food dependent on the individual. 4. The unilateral chewing and bruxism were not considered as possible contributing factors upon the occurring of temporomandibular joint sound. 5. Statistical significant association was found between clenching, stiffness, stress and tempore-mandibular joint sound, respectiely.(P<0.001, P<.01, P<0.05).

• 음성과학
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• 제15권1호
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• pp.53-62
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• 2008

The purpose of this study was to examine the English l sound in an English short story produced by 16 Korean students in order to determine various allophones of the sound using acoustic visual displays and perceptual judgments. The subjects read the story in a quiet office at normal speed. Each word included the lateral sound in onset or coda positions and before a vowel of the following word. Results showed as follows: Firstly, there was a durational difference between the two major groups. Also the majority of the subjects produced the clear l regardless of the contexts. Some students produced the sound as the Korean flap or the English glide [r]. A few missing cases were also seen. The dark l was mostly produced by the subjects of English majors in coda position with a few cases before a vowel in a phrase. Visual displays using the computer analysis were very helpful in distinguishing lateral variants but sometimes perceptual process would be necessary to judge them in fast and weak production of the target word. Further studies would be desirable to test the discrepancies between the acoustical and perceptual decisions.

• Journal of Chest Surgery
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• 제22권4호
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• pp.589-593
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• 1989

The frequency spectrum of the metallic closing sound and its loudness were measured by non invasive techniques in 66 patients. They had examined a total of 7 Carbomedics valve, 10 Duromedics valve, 11 St. Jude heart valve in mitral position and 8 Carbomedics, 10 Duromedics, 20 St. Jude heart valve prostheses functioning normally in aortic position. Statistical comparison of the loudness from sound produced by the three valves in each position, the following; The Carbomedics valve has the lowest average loudness, followed by the St. Jude medical valve, and finally the Edward Duromedics valve. And we analysis the changing factor of the loudness of valve sound, only the velocity of the flow through the valve influenced to the valve sound.

• Safety and Health at Work
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• 제8권2호
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• pp.226-230
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• 2017

The performance of sound barriers was evaluated to determine their technical effectiveness and practicality in reducing noise exposures to operating engineers in construction. Commercially purchased sound dampening mats (SDMats) were installed inside three heavy-equipment engine compartments. Sound pressure levels (SPLs) were measured before and after installing the SDMats while the equipment was on idle and full-throttle settings where it normally operates. SPLs inside the heavy-equipment operator cabs were significantly reduced by 5.6-7.6 dBA on the full-throttle setting following installation of the SDMats (p < 0.01). The evaluated engineering control intervention was simple to install, affordable, and substantially reduced the engine noise reaching the heavy-equipment operator, potentially reducing reliance on hearing-protection devices to protect construction workers from noise exposures.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1244-1249
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• 2002

In this study, the physical characteristics of steel-wire sound absorbing materials with different thickness and bulk density is experimentally obtained in terms of the porosity and specific flow resistivity. Based on the experimental results, the following conclusions can be made. The porosities of steel-wire sound absorbing materials are smaller than those of general absorbing materials, which are inversely proportional to the volume densities. For the porosity measurement with a good accuracy, the dynamic correction based on the system compliance should be involved in porosity measurement. In addition, the flow condition for the precise measurement of the specific flow resistivity of steel-wire sound absorbing materials should be limited in the laminar flow region.

• 비파괴검사학회지
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• 제30권3호
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• pp.207-211
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• 2010

In this paper, the fluid AID(acoustic inspection device) was developed to measure SOS(speed of sound) since fluids used in most of industrial fields have different properties and its equipment is highly expensive. From AID developed, it is intended to get potentially the capability to distinguish the kind of fluid using the measurement by the SOS at various fields. In order to measure the sound speed of specific fluids, the measurement system and ultrasonic sensors are composed. The fluid used in the experimental work are soybean oil, glycerin, diesel oil and the error of time difference due to the container wall is extracted for preliminary experiment. As results, the variations of sound speed according to the temperature change of target fluid were analyzed and the polynomial equations were proposed.

• 한국컴퓨터그래픽스학회논문지
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• 제15권1호
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• pp.25-34
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• 2009

사운드는 가상현실 및 컴퓨터 애니메이션에서 사용자의 현실감 및 집중도를 높이기 위한 중요한 요소이다. 최근에 컴퓨터 그래픽스 분야에서도 연구자들이 사운드 관련 연구들에 관심을 가지고 여러 컴퓨터 그래픽스 학술지와 학회에 주목할만한 연구결과들이 발표되고 있다. 본 논문에서는 컴퓨터 그래픽스 분야에서 소개된 논문들을 중심으로, 컴퓨터 그래픽스에서 관심을 가지는 사운드 연구의 주제에 대하여 알아보고 중요성을 가지는 논문들을 소개한다. 특히 본 논문에서는 다음 두 가지 분야의 논문들을 소개한다. 첫째, 사운드를 물리적으로 합성함으로써 그래픽스의 물리 법칙에 동기화되는 사운드를 생성하는 것이다. 둘째, 음원에서 나오는 사운드가 사람에게 들리는 음향적 환경을 모델링하는 것이다. 사운드에 대한 연구에서 주된 관심은 이러한 음향학적인 물리법칙을 더욱 효율적으로 모델링하여 적은 자원으로도 실제적인 사운드 효과를 발생할 수 있는지에 대한 것이다. 이러한 관점을 중점으로 다양한 사운드 관련 논문들을 살펴보고 컴퓨터 그래픽스와의 관계를 살펴보도록 한다.

• 한국소음진동공학회논문집
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• 제20권11호
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• pp.1018-1024
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• 2010

The printer noise consists of the noise of the various components and parts such as motor, fan and solenoid. And the human's printing sound recognition shows various aspects when the printer starts to print papers because the components operate at the same time. Especially, printers are usually installed in the quiet office room. Therefore the printing noise is related to its competitiveness in the market. The importance of the printer sound qualities is increasing and it is necessary to develop the sound quality evaluation system, so it is a key point to identify the noise source of the printer and develop the sound quality index to each component. By using this evaluation system, it is possible to evaluate the sound quality of a prototype printer compared to the already existing one. In this paper, the printer sound quality evaluation system was developed by the following steps. Firstly, the signal processing method was applied to the recorded printing sound to identity and split the noise of components. Secondly, the MLR(multiple linear regression) method and the psychoacoustics were used to develop the sound quality index. Finally, the improvement of the printer sound quality is possible by using the result of the MLR and the path analysis. The output of this research will be applied to the development of a new printer.