• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.427-430
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• 2008

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 present condition on noise level and types including residents' living noise 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. The results are as follows. 1) Averages of indoor noise levels of subject houses 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 as 'water hammer', 'living equipment noise', 'noise by family', 'hood noise', and '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 show 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 sound environment quality by residents' living noise in own unit as well as by neighborhood houses.

• Journal of odor and indoor environment
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• v.17 no.4
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• pp.346-354
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• 2018

In this study, the condition of the hazardous materials in the bus was monitored according to the ventilation mode of the air conditioning system during bus service. The bus was surveyed using the indoor air quality measurement method of public transportation vehicles within one year of delivery. We evaluate the $CO_2$ and $PM_{10}$, which are the controlled parameters in buses by the Ministry of Environment, and VOCs and HCHO, the non-controlled parameters. The $PM_{10}$ concentration increased due to outdoor air intake; however the $CO_2$ concentration was found to decrease. In addition, the concentration of VOCs and HCHO was found to decrease due to the forced ventilation system and the outdoor air intake. These results show that the concentration of the other materials except $PM_{10}$ can be changed due to the outside air concentration and forced ventilation system. Therefore, through indoor air quality characteristics of the bus according to air condition system are intended to be used as the basis of an operation manual.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.790-795
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• 2004

The characteristics of refrigerator noise recorded in anechoic chamber was investigated in condition of a the real living room and a kitchen. To predict the noise propagation in an apartment unit, room acoustic simulation software was used. It was found that the noise level in the real living room was $4\sim8dB$ higher than in the anechoic chamber. When a noise barrier and absorption materials were used on the rear wall and floor, the noise level reduced up to $3\sim4dB$. In addition, when the subjective evaluation of auralized refrigerator noise was undertaken using headphone, it was revealed that 21dB (A) is the allowable sound pressure level of 95% satisfaction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.225-228
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• 2009

The simulated indoor pass-by noise measurement system is the tool to measure and evaluate the pass-by noise at the test laboratory, without doing measurement at the field. This measurement system can realize the precision measurement under the specific condition and overcome the limitations of the field measurement, i.e. weather conditions, repeatability, .. This measurement system is done in time domain process using the array techniques, which synchronizes the time signals. The reliability of the obtained result depends on the array shapes, which can generate the moving source effect. In this paper, the validations are checked focusing the time domain synchronization of the signals with the optimum microphone array shape.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.6
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• pp.529-535
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• 2011

Indoor noise is very important related to the morale and fighting power of the crew as well as environmental condition for them in a navel vessel. Especially, the crew members working in CIC (combat information center) and sonar equipment room require much more quiet environment condition. One of the most serious noise source in CIC is the cooling fan noise installed in the console of the combat system. Therefore, in this paper, the design of the plenum chamber is studied to reduce the noise of the fan from these consoles by numerical analysis and experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.77-82
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• 2011

Indoor noise is very important related to the morale and fighting power of the crew as well as environmental condition for them in a navel vessel. Especially, the crew members working in CIC(Combat Information Center) and sonar equipment room require much more quiet environment condition in order to increase the performance of their combat system. One of the most serious noise source in CIC is the cooling fan noise installed in the console of the combat system. Therefore, in this paper, the design of the plenum chamber is studied to reduce the noise of the fan from these consoles by numerical analysis.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.517-523
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• 2016

Unlike household refrigerators, commercial refrigerators are composed of separate indoor and outdoor units. The outdoor unit of most commercial refrigerators is designed to run at a fixed speed, which results in low energy efficiency and loud fan noise. Moreover, it cannot respond flexibly to changing thermal load in the indoor unit. Inverter type outdoor units can address such problems through speed changes based on information obtained from the indoor unit. However, using two units from different manufacturers is often not a viable solution. If condition changes in the indoor unit can be detected without communication between the two units, it is possible to adjust the speed of the outdoor unit. This paper attempts to analyze the signal from the outdoor unit when the condition of the indoor unit changes by varying the thermal load.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.720-724
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• 2007

Recently, in accordance with increase of the desire for Sports for All(Life Sports), the swimming pools in many areas are under construction. However, since they used many of the reflexible finish-materials on account of the characteristics of hydrophilic space, most of the Indoor Swimming Pools are generating the excessive reverberation. Such reverberation is bringing about the problem that obstructs the oral communication between the coach and the player, and the Clearness of Sound, besides the sport activity. On this viewpoint, on the object of the actually built indoor swimming pool, after the conduct of an optimized acoustics design by the remodeling through a computer simulation, and by carrying out the Psycho-Acoustics Experiment utilizing of Auralization Technique which is able to experience Virtual Sound Field at the stage of designing, then this thesis has attempted to appraise on the acoustic condition after the completion of construction. It is considered that such result of the study could be utilized as the useful data that enables to improve the curtailment effect of construction cost as well as the acoustic capability, by means of the presupposition control on the acoustic problem from the stage of design, for the occasion when the similar indoor swimming pool is planning to build, henceforth.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.9-12
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• 2008

There are many place of business in complex building, and recently claims of noise have increased in those buildings. It is most desirable reducing the noise problems to establish the noise criteria considering the noise source and the receiving place of business, which are derived from the dose-response of noise and results of the actual condition. The degree of response to the transmission noise could be changed with background noise level in the receiving stores. In this research, the subjective evaluation for three different background level in receiving place of business or rooms were investigated from subjective tests. The eight business sound source including aerobic music were used for the test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.254-254
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• 2014

에어컨 실내기는 소비자와 근접해 있는 실내에 설치되며, 필요성에 의해 가동되므로 소비자들의 소음에 대한 반응이 민감하다. 실내기 소음에는 Fan Noise, Cricking Noise, Refringerant Noise 등이 존재한다. 이중 Refringerant Noise 의 경우 Overall Level 은 낮지만 거슬리는 소음이 발행하여 소비자의 가장 큰 불만을 초래한다. Refringerant Noise 에 대해 발생원인 및 해결 방안 측면으로의 연구는 활발히 진행 중이다. 그러나, 소음에 대한 평가 방법에 대한 연구가 이루어지지 않고 있다. 이에 본 연구에서는 에어컨 실내기 Refringerant Noise 을 대상으로 각 소음 별 특성 분석을 수행하였다. 이를 바탕으로 각 소음 별 영향인자를 도출하였다.