• 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.1014-1023
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• 2006

The purpose of this study is to propose the proper vocabularies for evaluating H.D TV set fan noise. To achieve this goal, psycho-acoustic experiments were carried out with TV set fan noise modulated at specific frequency band. Finally, a correlation analysis between vocabularies, and a factor analysis of psycho-acoustical responses were conducted. As a result of this study, followings are suggested. Analyzing the psycho-acoustical response corresponding to the various sound level, the higher the sound levels, the higher the response values were. It is estimated that the sound level determined psycho-acoustical responses. On the degree of response to fan noise, the initial level of negative feeling is located on $35{\sim}40$ dB(A). The factor of evaluating H.D. TV set fan noise has induced three the appropriate korean adjectives; Irritate, Monotonous, stuffy and dryness. The result of this study may be used to evaluate the acoustic threshold level for indoor noise or a basis for specifying the desired acoustic environment of dwellings.

• Journal of environmental and Sanitary engineering
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• v.18 no.3 s.49
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• pp.100-109
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• 2003

Recently, Indoor air quality(IAQ) in workplace, residential environments and schools has been concern of people, scientists and related the public. And so in Seoul has recognized the healthy effect related to IAQ in schools. Therefore, the objective of this study reported in this article were to measure and compare the perception of IAQ of selected air pollutants at three different schools in Seoul. We performed a questionnaire survey of 400 students about their awareness for the importance of IAQ in our school. And we measured the IAQ of 3 schools considering as site region, construction year and studying level. The indoor air pollutants and parameters such as temperature, relative humidity, respirable particulate matter(PM10), formaldehyde(HCHO), total bacteria counts(TBC), carbon dioxide(CO$_2$), and noise were monitored in indoors. In results, all most response of occupant has recognized the awareness of IAQ at schools. The PMIO, TBC and Noise level of all schools were higher than the standard of the public 150 ${mu}$g/m$^3$ and 500CFU/m$^3$, the level formaldehyde(HCHO) was below 0.1 ppm of the healthy guideline of Korea And the concentration of CO$_2$ were investigated below 1,000 ppm of the standard implying ventilation in 2 schools except for 1 school(c school). Finally, the control of most important pollutants of IAQ in school were PM10, TBC and Noise. Therefore, it can be concluded that the indoor air quality of selected 3 schools studied was perceived as acceptable, it is recommended that the government related IAQ was suggested the guideline and control of IAQ problems in schools, and all member relating school need to be effort to reduce the exposure of sources to undesirable indoor pollutants such as Particlate and Noise.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.5 s.122
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• pp.437-447
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• 2007

A series of research to seek for the relationship between subjective responses and noise level for transportation noise have been proceeded, and their results showed similar for some cases and different for some other cases as well, which is considered due to the various conditions such as the way of survey, different scale applied, and country etc. This study aimed to analyze the relationship between sound level and subjective response for the different kinds of transportation noise. The noises recorded in real situation were played to thirty subjects with fourty nine adjectives. The percentage of people annoyed(% PA) and the percentage of people highly annoyed(% HA) were calculated from the subjective results and compared how many percent of people are annoyed and highly annoyed for the same sound level. As a result of calculating the average, the aircraft noise was highest and the white noise lowest. The relationship between window TL and average point was well correlated except the aircraft noise which was scattered because of high sound level at specific frequency and low TL at corresponding frequency. This means that appropriate rating method for airborne sound transmission should be sought for to evaluate outdoor noise which has different frequency characteristics. The Boltzmann equation for % PA and % HA was applied to predict the sound level corresponding to the percentage. It is concluded that the aircraft noise and road traffic noise have almost same response and the railway noise was same with white noise, used for the reference noise, annoyed lower than other noises about by 3 dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.11-16
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• 2006

It appraises that use an indoor noise standard, a NC value which is a noise appraisal, a dB(A) value, a N value in foreign country because it doesn't yet ready an appraisal standard in domestic. Also, It appraises that the supply and drainage noise which could change water supply pressure, $4kg/cm^2,\;3kg/cm^2,\;2kg/cm^2,\;1.5kg/cm^2,\;1kg/cm^2$, bring about a noise and inquires how does noise level indicates according to each instruments. In case of a water supply pressure standard, $3kg/cm^2$, a C-605is $3{\sim}5dB(A)$ lower than another instruments in directly overhead stories. It appears that all of them is similar to level in directly under level except c-407(2)Analyzed the NC value, c-605is the lowest level, NC-50, of a water supply pressure, $4.0kg/cm^2$, c-407 is the highest level, NC-55.(3) In case of N value, which is one of water supply methods in Japan, it is the lowest level, N-55, of a water supply pressure, $4.0kg/cm^2$ same as NC value and C-407is the highest level, N-60.(4) In case of water supply that is likely to noise level, It appears 6dB(A) level gap each instruments, and C-605 is the lowest level, 63.9dB(A).

• KIEAE Journal
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• v.9 no.1
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• pp.99-106
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• 2009

This study aims to survey the acoustical environment in the region around airport where there are various transportation noises such as aircraft noise, railway noise and traffic noise, and to analyze the subjective response on the noise to the people who live in house or work in office nearby airport. Measurement and subjective response evaluation were carried out at the same time and outdoor noise level was measured all day long to calculate one day results such as average Leq or one day WECPNL etc. The results showed that the military aircraft produces very high level comparing with commercial aircraft, for instance the sound level of commercial outdoor was lower than that of military aircraft indoor. Double and triple window were more effective for controlling the noise than single window, which showed the possibility of sound insulation treatment by installing windows having higher sound insulation performance. Finally the subjective response was resulted that the most annoying noise is from aircraft and counterplan they hope is 'airport moving out'. Leq 65 dB(A), the criteria value of sound insulation treatment, was corresponding to the subjective response of median annoyance '4' out of 7th scale.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.249-250
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• 2023

The objective of this study is to evaluate the airborne sound insulation performance between housing units and community facilities during the construction phase. Community facilities adjacent to housing units can lead to noise problems, hence it is necessary to minimize noise transmission during the design phase. However, flanking noise transmitted through gaps of structures, windows, pipes, and other openings may result in substandard sound insulation performance falling below the design standards. Therefore, It is crucial to measure airborne sound insulation in the field during the construction phase. The measurement was conducted using the survey method for the field measurement of the airborne sound insulation in accordance with KS F ISO 10052:2021. Although the noise standards caused by community facilities in apartment complexes are not specified in current laws and regulations, desired noise level was set based on international guidelines for indoor noise. First, the level of noise generated in community facilities was estimated, and then the sound insulation performance was evaluated to determine whether the desired noise level was achieved.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.5
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• pp.394-400
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• 2018

Various numerical methods have been adopted for indoor noise assessments of ship plant. Acoustical radiosity method is one of the high frequency approaches for acoustic field analysis, which assumes diffuse reflections by boundaries so that it could be efficiently applied to the acoustically diffused indoor space noise analysis. In this study, an acoustic field analysis program has been developed based on radiosity method, which could apply for acoustically large enclosures such as ship's indoor space. For this purpose, the procedure of the acoustical radiosity method has been summarized and implemented to an acoustic field analysis program using MATLAB. Numerical example for a rectangular indoor space has investigated validity of the implemented program. Steady state sound pressure levels calculated for a continuous acoustic source signal have shown good agreement with those by other solutions such as an analytic solution and a ray tracing method. Instantaneous sound pressure levels calculated for an impulsive acoustic signal have provided the clues of direct/reflected acoustic field and reverberation time.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.1
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• pp.69-77
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• 2021

The noise environment was evaluated using the ISO recommended NR evaluation curve and PSIL (Preferred Sound Interference Level) in order to investigate the onboard educational environment according to the noise in the Motor Vessel Saehaerim, a fishing training ship under making way. As a result, NRNs were measured at 37-61 dB in accommodation areas, 44-56 dB in work areas, 37-57 dB in educational and conference areas, 83-103 dB in engine areas and 65.3 dB and 51.2 dB in the work and education areas respectively based on PSIL. The NRNs, which evaluated the cabin of the experimental ship according to the purpose, exceeded all of the indoor standard noise recommended by the ISO, and the PSIL had a generally short conversational distance within 0.25-2.3 m and 0.75-1.3 m for teaching and work areas.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.547-552
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• 2002

The purpose of this study is to propose indoor noise level in residential buildings affected by transportation noise (road traffic, railway and air-craft noise) based on subjective evaluations, 30 subjects participated in the experiment to evaluate the noise. Experimental environment reproduced real living and office environment, and in asking subjects' annoyance to the noise. An experiment to investigate the subjective responses to various computer noises (CD-Rom, HDD, Fan) in office environment was also undertaken. The Result shows that the lower limit of transportation noise is $40{\sim}41dB(A)$ and upper limit is $55{\sim}60dB(A)$, whereas the lower limit of various computer noises is $36{\sim}40dB(A)$ and upper limit is $45{\sim}52dB(A)$.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.1
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• pp.41-48
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• 2014

This paper analyzes the Monte Carlo localization (MCL) method, which estimates the pose of an indoor mobile robot. A mobile robot must know where it is to navigate in an indoor environment. The MCL technique is one of the most influential and popular techniques for estimation of robot position and orientation using a particle filter. For the analysis, we perform experiments in an indoor environment with a differential drive robot and ultrasonic range sensor system. The analysis uses MATLAB for implementation of the MCL and investigates the effects of the control parameters on the MCL performance. The control parameters are the uncertainty of the motion model of the mobile robot and the noise level of the measurement model of the range sensor.