• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.609-614
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• 2011

The ship working environment of combat service support boat is much inferior to the ground working environment. For this reason, the crew of a combat service support boat suffer from an occupational disease such as hardness of hearing. Owing to its small size and low status, the improvement of its working and residential environment was occasionally ignored and its indoor noise was not fully investigated. In this study, for improving its residential environment indoor, the indoor noise of its shipboard compartments was analysed. These studies define the indoor noise level of combat service support boat is very high and some of indoor noise is exceeded the criteria for ship noise. Compared with marine police vessels, the indoor noise levels of marine police vessels are higher than the level of combat service support boat.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.83-86
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• 2005

The aim of this study is to establish the indoor noise limits of apartment houses for mad traffic noise. To achieve this goal, psycho-acoustic experiments were carried out with the mad traffic sound sources modulated by the transmission loss characteristics of the external windows. As a result of this study, followings are suggested. 1) On correlation between dose level and psycho-acoustical response, the initial level of negative feeling is located on $40.1{\sim}40.6$ Leq dB(A). 2) On the degree of satisfaction to road traffic noise, near 35% Point being same dissatisfaction degree is to be assumed $40{\sim}41$ dB(A) of indoor noise level presented into three vocabulary. It is suggested to be reasonable level of 40 dB(A) on the indoor noise limits for intruding road traffic noise, and it is appropriate to be the 5dB level difference between grades.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2003.11a
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• pp.95-100
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• 2003

The purpose of this study is to evaluate the noise environment of one-room type multi-family housing around the campus. The field measurements on equivalent noise level of indoor and outdoor were carried out in 6 subject house units during the 26th${\sim}$28th of November 2002. The results are as follows. 1) Outdoor noise levels of 6 subject buildings were distributed 52.8${\sim}$65.3dB(A) and were inappropriate to the standard for environmental noise, 55dB(A). 2) Indoor noise level of 6 subject house units were measured 27.5${\sim}$63.5dB(A). These values were higher than the indoor noise standard (40dB(A)) except subject house D(average 37.6dB(A)). 3) It was found that the differences of indoor noise levels between subject house units were caused by resident's living factor, characteristics of window, and existence of balcony.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.142-149
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• 2000

It is required that the indoor-noise level of KHST (Korean high speed train) should be lower than 66 ㏈(A) at 350 km/h. In this study, the indoor-noise level of KHST has been predicted to determine the maximum allowable sound power levels of major noise sources. It is found that the indoor-noise requirement for KHST can be met by increasing the transmission losses of the floor and side-wall structures as well as by lowering the sound power levels of two major noise sources including the motor fans.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.1
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• pp.9-17
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• 2022

As the COVID-19 pandemic situation worsens, the time spent indoors increases, and the exposure to indoor environmental pollution such as indoor air pollution and noise also increases, causing problems such as deterioration of human health, stress, and discord between neighbors. This paper designs and implements a system that measures and monitors indoor air quality and noise, which are representative evaluation criteria of the indoor environment. The system proposed in this paper consists of a particulate matter measurement subsystem that measures and corrects the concentration of particulate matters to monitor indoor air quality, and a noise measurement subsystem that detects changes in sound and converts it to a sound pressure level. The concentration of indoor particulate matters is measured using a laser-based light scattering method, and an error caused by temperature and humidity is compensated in this paper. For indoor noise measurement, the voltage measured through a microphone is basically measured, Fourier transform is performed to classify it by frequency, and then A-weighting is performed to correct loudness equality. Then, the RMS value is obtained, high-frequency noise is removed by performing time-weighting, and then SPL is obtained. Finally, the equivalent noise level for 1 minute and 5 minutes are calculated to show the indoor noise level. In order to classify noise into direct impact sound and air transmission noise, a piezo vibration sensors is mounted to determine the presence or absence of direct impact transmitted through the wall. For performance evaluation, the error of particulate matter measurement is analyzed through TSI's AM510 instrument. and compare the noise error with CEM's noise measurement system.

• Journal of the Korean housing association
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• v.20 no.1
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• pp.83-90
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• 2009

The present study is a preliminary research improving the dwelling quality of apartment house as a kind of multi-family housing. The purpose of the study is to find out the actual state on characteristics of indoor noise including residents' living in apartment units. The method was field survey consisted of field measurements on equivalent noise level, observation on noise type, and interview on residents' responses. Field survey were carried out in 20 occupied apartment units from January to March 2007. The results are as follows. 1) Averages of indoor noise levels including residents' living noise were measured as $43.9{\sim}62.2\;dB(A)_{Leq5min}$, the average of each house except one was higher than the permissible level, 45 dB(A). 2) The noise types observed were mostly residents' living noise and classified into 'water hammer', 'living equipment noise', 'noise by family', 'hood noise', 'kitchen noise' in own unit, 'walking and talking noise in stairs and corridors', 'noise by neighborhood house', 'noise by the upper story' in building, and outdoor noise. 3) The residents showed slightly non-positive responses at 'noise by the upper story', 'noise by neighborhood house', 'water hammer', and 'noise by family'. Therefore, it is required to plan for preventing deterioration of the dwelling quality by residents' living noise in own unit as well as by neighborhood houses.

• Korean Institute of Interior Design Journal
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• v.14 no.3 s.50
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• pp.191-198
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• 2005

The present study is a preliminary research improving the dwelling quality of one-room type multi-family housings around the university campus. The purpose of the study is to investigate the present condition of Indoor noise level using · residents' responses and field measurements. The respondents are 104 residents living in one-room type multi-family housings. The field measurements on equivalent noise level of indoor and outdoor were carried out in 6 subject house units during the $26th\~28th$ of November 2002. The results are as follows. 1) The residents show relatively non-positive responses at evening and night on the present condition of indoor noise. 2) They answer 'living equipment foise' and 'water hammer' as major types of indoor noise of house unit. 3) Outdoor noise levels, basic factor of noise environment in 6 subject buildings were distributed $52.8\~65.3dB(A)Leq_{5min}$ and were inappropriate to the standard for environmental noise, $55 dB(A)Leq_{5min}$. 4) Indoor noise levels of subject house units were measured as $27.5\~63.5dB(A)Leq_{5min}$, the average of each house unit except one house unit was higher than the level feeling as noise, 40dB(A). 5) It was found that the differences of indoor noise levels between subject house units were caused by 'residents' living noise', 'living equipment noise', 'water hammer', and 'walking and talking noise in stairs and corridors'. 6) Therefore, it is required to plan for improving the quality of noise environment in one-room type multi-family housing around the campus. For example, soundproof construction (including double window with pair glass and balcony), outdoor garden with trees and water for increasing natural sound, interior materials with sound absorbing power to absorb living noise, soundproof pipe or double surface pipe for decreasing 'water hammer', and noiseproof floors, etc. are required.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2007.05a
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• pp.85-88
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• 2007

This research is a case study for improving the sound environmental quality of cafeteria in university campus. The purpose of the study is to investigate the present condition of physical level, type, and source of indoor noise by comparison with a restaurant near campus. Methods were field survey with measurement on equivalent and instant noise level and observation on noise type, and questionnaire survey to 60 students users. Surveys were carried out in the 8th and the 14th of December 2005. The results are as follows. 1) Indoor noise levels of the cafeteria were measured as $67.2{\sim}76.6$(average 73.3) dB(A)Leq5min and $60.3{\sim}90.5$(average 71.2) dB(A), but noise levels of the restaurant were $61.6{\sim}70.4$(average 66.9) dB(A)Leq5min and $59.8{\sim}70.6$(average 64.9) dB(A). 2) The users's responses on major noise type were 'noise by handling equipment and tableware', 'noise by moving chairs', and 'taking noise' in cafeteria, but 'taking noise' and 'background music' in restaurant. 3) It was found that the differences of indoor noise condition between with 2 subjects were caused by finishing materials, kitchen division type, and furniture type.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.650-656
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• 2011

The noise inside a naval vessel is very important in considering the need for hearing protection, improving the working environment and maintaining good communications for crews living on board a naval vessel. The indoor noise of a ship usually is specified by the A-weighted sound pressure level, but other evaluating parameters are required to reflect human senses more effectively. This paper uses additional noise indices related to room acoustics, such as NR(noise rating), NC(noise criterion), RC(room criterion), PSIL(preferred speech interference level) and loudness level to evaluate the noise inside cabins on a naval vessel. Using these psychological noise indices, allowable limit of noise level in cabins is suggested through psycho-acoustic evaluation for the noise in cabins.

• Journal of the Korean housing association
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• v.18 no.5
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• pp.85-91
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• 2007

This is a case study for improving the sound environmental quality of cafeteria in university campus. The purpose of the study is to find out the present condition of physical level, type, and cause of indoor noise of cafeteria in university campus by comparison with a restaurant near campus. Research methods were field survey and questionnaire survey. Field survey was consisted of measurement on equivalent and instant noise level and observation on noise type. Respondents of questionnaire survey were 60 students using subject cafeteria or restaurant. Surveys were carried out in the 8th and in the 14th of December 2005. The results are as follows. 1) Indoor noise levels of the cafeteria were measured as $67.2{\sim}76.6$ (average 73.3) dB(A)Leq5min and $60.3{\sim}90.5$ (average 71.2) dB (A), exceeded the indoor noise recommended value of ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers). But noise levels of the restaurant were $61.6{\sim}70.4$ (average 66.9) dB(A)Leq5min and $59.8{\sim}70.6$ (average 64.9) dB(A). 2) The users's responses on major noise type in the cafeteria were 'noise by handling equipment and tableware', 'noise by moving chairs', and 'talcing noise', but 'taking noise' and 'background music' in the restaurant. 3) It was found that indoor noise level of the cafeteria was caused by sound reflection of finishing materials, noise diffusion by open type kitchen, and dragging noise of movable furniture.