• The Journal of the Acoustical Society of Korea
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• v.32 no.5
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• pp.423-429
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• 2013

The present study aimed to find the most sensitive placement of the skull to perceive speech through the bone vibrator in various protection methods while being exposed to noise. Twenty young normal-hearing adults (10 male and 10 female) participated in the study. As stimulus, Korean spondee words were presented via one of five skull locations (i.e., jaw angle, condyle, temple, mastoid, and vertex), while the participants wore one of four protection methods (i.e., ear form, ear plug, ear muff, and ear form and muff together) against white noise in one of four noise directions (i.e., 0, 90, 180, 270 degrees). The results showed: 1) there was a significant difference among the five skull locations with condyle being the most sensitive placement; 2) there was a significant difference among the four protection methods, with the ear form plus ear muff condition (or dual protection) providing the lowest threshold; 3) when exposed to noise from 90 degrees, the significantly lowest threshold was found; 4) there was no significant difference in results by gender. The pattern of results suggests that the communicative condition via the condyle bone conduction and the dual protection of the air conduction under any noise direction might be ideal for preventing noise-induced hearing loss, although further studies should be undertaken in this area.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.580-586
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• 2005

In this study, experimental tests for driving noise of various optical disk drives (ODD) have been performed using 1/2' microphone noise measurement system. Several new and old ODD models by different manufacturers are practically considered and compared far realistic driving conditions. Sound insulation case with absorbing material fur the present experimental tests is designed and constructed using CATIA system. It is found that average data transfer rate, operating RPM, and sound noise level seems to be different for the same opposed speed ODD by different manufacturers. Moreover, driving sound noise level can be largely affected by both tray shape and driving speed even for the same apparent data transfer rate.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.10 s.103
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• pp.1169-1176
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• 2005

In this study, experimental tests for driving noise of various optical disk drives (ODD) have been performed using 1/2' microphone noise measurement system. Several new and old ODD models by different manufacturers are practically considered and compared for realistic driving conditions. Sound insulation case with absorbing material for the present experimental tests is designed and constructed using CATIA system. It is found that average data transfer rate, operating RPM, and sound noise level seem to be different for the ODD models with same denoted speed by different manufacturers. Moreover, driving sound noise level can be largely affected by both tray shape and driving speed even for the condition of the same apparent data transfer rate.

• Journal of the Korea Institute of Building Construction
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• v.15 no.1
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• pp.123-131
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• 2015

The purpose of this study is to analysis the noise characteristics about noise type, sound level, and noise occurrence frequency of living noise in residential buildings. The field measurement was conducted to classify the types of living noise and to examine the actual states of noise occurrence for each living noise source. Among the 24 types of living noise, 10 noise sources were selected based on the loudness and frequency of each living noise. The result indicated that 10 noise sources show the difference on each noise occurrence characteristic by time zones. Therefore, to reduce noise, a management plan should be introduced based on the actual state of the noise occurrence, considering the individual noise source and the time slot during noise frequently occurs. Moreover, the noise standard for each noise types of living noise should be specificated and the education for residents about characteristics of living noise types should be conducted to improve the consciousness of residents.

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.141-146
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• 2019

The aircraft noise analysis area in this study is a training airfield where various kinds of aircraft are operated. It is difficult to identify the noise analysis as a real measurement in a training airfield. In order to overcome these practical limitations and to establish appropriate noise countermeasures, a noise map is prepared using the Integrated Noise Model Version 7.0 of the aircraft noise prediction program used by the FAA. The noise of C90GT aircraft was measured while flying the takeoff route, landing route, and long route. We want to identify areas where noise damage is more than 70 WECPNL. No area exceeding the legal standard of 70 WECPNL was found in all routes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.65-69
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• 1991

소음제어대책 수립시, 흡음구조는 공조용소음기, 공업용소음기, Enclosure, 실 내 흡음판등에 폭넓게 이용되고 있다. 흡음구조의 재료중 글라스울은 뛰어난 흡음성능과 고온에서의 내구성 및 난연성등으로 인하여 여러 흡음재료중에 서 가장 많이 이용되고 있으나 글라스율 미립자의 비산 및 강도문제로 글라 스율에 글라스 클로스(Glass Cloth), P.E.Film등과 같은 글라스울 비산방지막 과 유공함석판을 붙인 흡음구조체로 제작하여 이용하는 것이 일반적이다. 국 내외적으로 글라스울만의 흡음율 데이타는 각종 문헌등에 많이 발표되어 있 으나 글라스울에 글라스울 비산방지막과 유공함석판을 붙인 흡음구조체의 흡음율데이타는 거의 없는 실정이다. 본 연구에서는 이러한 글라스울 흡음구 조체의 글라스울의 밀도, 글라스울 비산방지막의 종류, 유공함석판의 유공치 수 등에 따른 흡음특성을 잔향실법 흡음율측정방법에 의해 측정 평가하고 이들을 상호 비교검토하여 각종 소음 제어대책의 기초 설계자료로 제시하고 자 한다.

• The Journal of the Acoustical Society of Korea
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• v.19 no.6
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• pp.23-27
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• 2000

Noise can be defined as any undesired or loud sound. The sound level of mobile phone ring tones could be considered as noise if it is too loud on a specific situation. To classify a specific sound level of mobile phone ring tones as noise, it is useful to evaluate the mean opinion scores(MOS) on sound levels under some specific situations. The paper evaluates MOS on various sound levels (in dBA) of mobile phone ring tones, types of ring tone(bell/melody), and gender(male/female), location (street/office).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.223-230
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• 1995

본 연구에서는 선박소음해석을 수행하기 위한 기초작업으로서 실선 선박모델을 크게 3가지 경우로 구분하여 모델링 하였으며, SEA법을 적용하여 고체소음의 전달손실을 이론적으로 예측할 수 있는 방법을 제시하였으며, 또한 STL을 도입하여 각 요소간의 에너지 흐름 및 구성판요소의 재료별 방진효과를 알아보았다. 이 방법의 결과 다음과 같은 결론을 얻을 수 있었다. 1) 내장판의 종류에 따른 전달특성은 고주파 대역에서는 plywood, 저주파 대 역에서는 rockwool이 높은 손실값을 보였으며, glasswool은 전 주파수 대역에서 고른 손실값을 가짐을 확인하였다. 2) 기진원으로부터의 거리가 멀어짐에 따라 내장판의 효과가 크게 나타나며, 기진원의 근방 요소에서는 내장판의 효과보다는 강판의 두께의 영향이 두드 러짐을 알 수 있었다. 3) 내장판 요소중 plywood의 방진효과가 가장 크게 나타남을 알 수 있었다. 4) 본 SEA법에 의한 연구에서는 구성 판요소의 재질과 두께에 따른 고쳇음 의 전달특성을 이론적으로 해석하였으며, 차후 실험을 통한 검증이 요구되어 진다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1067-1073
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• 2006

In this paper, we present noise measurement results of 8 vehicles. The measurement was done by a close proximity method attaching surface microphones on the test vehicle. For the 9 road surface types constructed at Korean highway test road, the vehicles were tested from 50 to 120 km/h at the interval of 10 km/h in normal steady state and inertia cruising conditions. Using the results, we evaluate and discuss the effect of vehicle noise generation depending on the different conditions for vehicle type, speed, road surface and loading condition, especially focused on friction noise between tyre and road surface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.428-433
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• 2006

In this paper, we present noise measurement results of 8 vehicles. The measurement was done by a close proximity method attaching surface microphones on the test vehicle. For the 9 road surface types constructed at Korean highway test road, the vehicles were tested from 50 to 120 km/h at the interval of 10 km/h in normal steady state and inertia cruising conditions. Using the results, we evaluate and discuss the effect of vehicle noise generation depending on the different conditions for vehicle type, speed, road surface and loading condition, especially focused on friction noise between tyre and road surface.