• 한국음향학회지
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• 제21권8호
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• pp.695-702
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• 2002

소리가 나는 방향을 어떻게 사람이 인지하는가 라는 질문은 전통적인 심리 음향학적 문제 중하나이다. Rayleigh는 이미 1870년대부터 이에 대하여 연구를 수행하였고 이에 대한 관심은 수그러들었다가 되살아나는 방식으로 연구 경력 말기까지 그의 머리를 떠나지 않았다. 이 연구 주제는 소리 지각에 대한 Rayleigh의 유일한 관심사이면서도 음향학의 다른 연구 주제보다 더 많은 관심을 쏟은 주제였다. 그는 당초에 세기차에 의한 소리의 방향 지각을 주장하다가 위상차에 의한 방향 지각을 받아들이는 쪽으로 생각이 옮아갔다. 그리하여 그는 높은 진동수의 음에 대해서는 세기차를, 낮은 진동수의 음에 대해서는 위상차를 감지함으로써 소리의 방향 지각이 이루어진다는 현대적인 결론에 도달했다. 이러한 과정에서 Rayleigh는 매우 주의 깊고 정교한 실험방법을 채용함으로써 탁월한 음향학 실험가로서의 면모를 드러냈을 뿐 아니라 수학적 이론화의 성과를 그의 실험에 연결시킴으로써 설득력 있는 결과를 얻었다.

• 대한통합의학회지
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• 제6권4호
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• pp.191-206
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• 2018

Purpose : This study investigated the correlation between speech intelligibility and acoustic measurements of speech sounds produced by the children with speech sound disorders and children without any diagnosed speech sound disorder. Methods : A total of 60 children with and without speech sound disorders were the subjects of this study. Speech samples were obtained by having the subjects? speak meaningful words. Acoustic measurements were analyzed on a spectrogram using the Multi-speech 3700 program. Speech intelligibility was determined according to a listener's perceptual judgment. Results : Children with speech sound disorders had significantly lower speech intelligibility than those without speech sound disorders. The intensity of the vowel /u/, the duration of the vowel /${\omega}$/, and the second formant of the vowel /${\omega}$/ were significantly different between both groups. There was no difference in voice onset time between the groups. There was a correlation between acoustic measurements and speech intelligibility. Conclusion : The results of this study showed that the speech intelligibility of children with speech sound disorders was affected by intensity, word duration, and formant frequency. It is necessary to complement clinical setting results using acoustic measurements in addition to evaluation of speech intelligibility.

• 소음진동
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• 제9권4호
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• pp.761-768
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• 1999

This paper presents an NVH test of Automotive power steering system performed at a half-car Test-rig. The test was done for neutral and full turn(or relief) conditions in steering wheel at a fixed rpm first, then followed by the same conditions for the rpm run-up. The sound intensity measurement verified the results from the frequency and order analysis, especially about the identification of major noise sources and their dominant frequencies. The results from thie study can be utilized in the system noise tuning when a new steering component is installed. In particular, the noise and vibration reduction at the relief condition will be accomplished through the knowledge obtained from this study and from the on-going research on the hose tuning techniques usign silencers and tuning cable inserted in the pressure hose.

• 한국산학기술학회논문지
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• 제15권12호
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• pp.6993-6997
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• 2014

본 연구의 목적은 자성유체 스피커의 보이스 코일 방열 및 음질 저하 문제를 극복하기 위하여 무향실내에서 자성유체 스피커의 음 왜곡률, 음압레벨 및 주파수 특성과 같은 음질 성능 특성을 고찰하는 것이다. 이를 위하여 자성유체 스피커에서 자성유체 주입량 및 영구자석 자력을 변화시켜가면서 음압 성능을 측정하였다. 그리고 스피커의 음 왜곡률, 음압레벨 및 주파수 특성은 음향시스템 측정 프로그램인 Smarrt를 이용하여 측정하였다. 결과적으로, 자성유체의 주입량은 2.4 ml로 결정되었고, 자성유체를 주입할 경우 음 왜곡률 및 음압레벨은 향상되었다. 자성유체 스피커에서 영구자석의 자력을 8.06 mT에서 9.10 mT로 증가시킬 경우 주파수 특성 및 음압레벨은 더욱 향상되었다. 또한, 자성유체 스피커의 음 왜곡률은 일반 스피커에 비하여 약 0.01% 감소하였다.

• Animal Bioscience
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• 제35권9호
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• pp.1454-1460
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• 2022

Objective: Early environmental enrichment in life can improve cognition in animals. The effect of prenatal auditory stimulation on learning ability and fear level in chick embryos remained unexplored. Therefore, this study investigated the effect of prenatal auditory stimulation on the learning ability and fear level of chicks. Methods: A total of 450 fertilized eggs were randomly divided into 5 groups, including control group (C), low-sound intensity music group (LM), low-sound intensity noise group (LN), high-sound intensity noise group (HN) and high-sound intensity music group (HM). From the 10th day of embryonic development until hatching, group LM and group LN received 65 to 75 dB of music and noise stimulation. Group HN and group HM received 85 to 95 dB of noise and music stimulation, and group C received no additional sound. At the end of incubation, the one-trial passive avoidance learning (PAL) task and tonic immobility (TI) tests were carried out, and the serum corticosterone (CORT) and serotonin (5-HT) concentrations were determined. Results: The results showed that compared with the group C, 65 to 75 dB of music and noise stimulation did not affect the PAL avoidance rate (p>0.05), duration of TI (p>0.05) and the concentration of CORT (p>0.05) and 5-HT (p>0.05) in chicks. However, 85 to 95 dB of music and noise stimulation could reduce duration of TI (p<0.05) and the concentration of CORT (p<0.05), but no significant effect was observed on the concentration of 5-HT (p>0.05) and PAL avoidance rate (p>0.05). Conclusion: Therefore, the prenatal auditory stimulation of 85 to 95 dB can effectively reduce the fear level of chicks while it does not affect the learning ability.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1399-1400
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• 2010

• 대한치과보철학회지
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• 제31권1호
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• pp.51-61
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• 1993

The purpose of this study was to evaluate a possible occlusal contributing factor on the pathogenesis of temporomandibular joint sound by a new computer aided method for analysis of occlusal contact. 20 subjects without temporomandibular joint sound as control group and 20 subjects with temporomandibular joint sound as experimental group in the TMJ clinic, dental infirmary, School of Dentistry, Chosun University were selected so as to investigate the distribution and intensity of the bilateral occlusal contacts on silicone rubber bites in habitual intercusal position through a computer aided system. The following results were obtained : 1. The distribution and intensity of the occlusal contact could be analyzed and expressed as color density value per levels by this computer aided method. 2. There was not statistical significance between control and experimental group in total occlusal contacts. 3. There was statistical significance between control and experimental group In the total difference of right and left occlusal contacts.(P<0.05).

• 소음진동
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• 제8권6호
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• pp.1043-1052
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• 1998

The noise sources in the outdoor unit of RAC are identified by the sound intensity method. The main noise sources are compressor noise and fluid noise which is caused by the fan. heat exchanger and shroud. First. the fluid noise is reduced through the design of new fan and shroud. reduction of the system resistance by rearrangement of heat exchanger. and optimization of the complex parameter between the fan and shroud. Next, in order to reduce the compressor noise, the new shape of compressor mount and sound-proof material was applied. As a result, the overall noise was reduced by 4∼5dB (A).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.87-87
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• 2004

An air-conditioner has various noise sources such as a fan noise, a motor noise, and a vibration induced noise. To reduce these noise effectively, noise sources must be identified. Especially in this paper, the structure borne sound radiated from the motor bracket of the indoor air-conditioner is considered. To do this, the operational deflection shape, which is used for understanding of the behavior of the motor bracket at a particular frequency, is obtained and compared with the sound intensity, which is used for the noise identification. Through this study, the noise sources of indoor air-conditioner are defined and the effective noise reduction method is proposed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.210-215
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• 2001

CD-ROM Drives Rotating high speed as 10000 rpm cause serious noise and vibration problems. At the high speed, dominant noise is Air Borne Noise produced from high-speed airflow and Structure Borne Noise produced from structural vibration. In this research, vibration and sound characteristics in CD-ROM Drive were studied by the use of experimental analysis and computational simulation. Sound intensity techniques and ODS(Operational Deflection Shape) techniques are applied to identify the acoustic noise source of CD-ROM drive. And Computational simulation using SYSNOISE is conducted for describing the noise behavior.