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

• Journal of the Ergonomics Society of Korea
• /
• v.34 no.3
• /
• pp.265-278
• /
• 2015

Objective:To study the sources of indoor noise, its effects on human health, noise assessment and regulation through the use of standards, and techniques used to reduce noise. Background: Noise significantly affects the living environment, and there are an increasing number of reports of its impacts on human health. Method: We reviewed domestic and foreign data regarding environmental noise, and examined its effects and the standards used to regulate noise levels. Results: We describe the major sources of indoor noise and suggest possible legal standards, as well as recommended criteria for the control of noise. Conclusion: South Korea has higher legal standards of environmental noise than international standards in terms of threshold values. People in Korea are exposed to various sources of noise, and therefore the reduction of noise is urgently required. Application: Depending on the features of indoor spaces, an appropriate degree of indoor noise can be determined and techniques to reduce excess noise are required.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.17 no.1
• /
• pp.9-17
• /
• 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 Society of Safety
• /
• v.30 no.4
• /
• pp.142-150
• /
• 2015

A portable recoilless guided missile generates a strong back blast and impulsive noise at the nozzle when it launches. In the case of indoor operations, the hazard of the blast noise from a recoilless weapon increases due to limited indoor spaces. Also, the noise levels determine the operational feasibility of a weapon; therefore, it is important to predict the blast noise levels distribution in the indoor space in advance. In addition, computational fluid dynamics (CFD) method generally used for fluid related simulations, requires high computing cost and time to simulate the whole domains. The domain includes both blast wave region and large and various indoor space region. Therefore, an efficient method for predicting the far-field noise level within a short time should be developed. This paper describes an analysis model for predicting the indoor noise distributions by considering the shape effect of the building within a short time. A new developed blast wave model was implemented using the noise source. Additionally, noise reflections at the closed surfaces such as walls and noise transmissions at the opened surfaces such as windows and doors were considered in calculating the noise levels. The predicted noise levels were compared with the experimental data obtained from the indoor launch test to validate the reliability of program.

• Journal of the Korean Home Economics Association
• /
• v.27 no.1
• /
• pp.85-96
• /
• 1989

The purpose of study was to survey the indoor noise of apartment houses, residents, attitudes and their adaptation behavior in order to offer the information helpful to apartment designers and residents, in their housing policy. Documentary research and questionnaire survey methods were used in this research. The sample was taken from 187 housewives living in apartments in Seoul. Data were analyzed with the SPSS program. The results were as follow : 1. It was found that apartment residents pointed out washing machine noise inside the home, piano and other musical instruments noise outside the home. 2. Piano and other musical instrument noise were heard at 3 to 6 pp.m. when residents heard the noise, and water supply and drainage noise in bathrooms were found most noisy. 3. Apartment residents were discontent with noise outside the home, and they displayed positive adaptation behavior at a reduced noise level. 4. Attitudes arising from indoor noise in apartment houses and human noise, water supply and drainage noise, doorway opening and closing noise were found to be significant in sampled apartment groups. 5. The youngest child's age was a significant variable on the residents' attitudes and adaptation behavior of indoor noise in apartment houses. 6. Between the resident' attitudes and adaptation behavior involving indoor noise in apartment houses. 6. Between the resident' attitueds and adaptation behavior involving indoor noise apartment houses, the more they became discontented, the more quickly they adapted in a postive manner.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.892-896
• /
• 2001

Recently, many indoor driving ranges are being built near residential areas because golf is one of the popular sports. Consequently, environmental noise occurs in the residential areas. This study is to predict the noise near the indoor golf driving range by the computer simulation(commercial software Raynoise 3.0) for various cases of noise control methods.

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

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

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

• Journal of the Korean Society for Railway
• /
• v.4 no.1
• /
• pp.9-15
• /
• 2001

It is required that the indoor-noise level of KHST (Korean High Speed Train) should be lower than 66 dB(A) at 300 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 requirements 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 the major noise sources.