• Asian Journal of Atmospheric Environment
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• 제8권1호
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• pp.35-47
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• 2014

The purpose of the study is to evaluate the pollution level (gaseous and particle phase) in the public facilities for the PAHs, non-regulated materials, forecast the risk level by the health risk assessment (HRA) and propose the guideline level. PAH assessments through sampling of particulate matter of diameter < 2.5 ${\mu}m$ ($PM_{2.5}$). The user and worker exposure scenario for the PAHs consists of 24-hour exposure scenario (WIES) assuming the worst case and the normal exposure scenario (MIES) based on the survey. This study investigated 20 PAH substances selected out of 32 substances known to be carcinogenic or potentially carcinogenic. The risk assessment applies major toxic equivalency factor (TEF) proposed from existing studies and estaimates individual Excess Cancer Risk (ECR). The study assesses the fine dusts ($PM_{2.5}$) and the exposure levels of the gaseous and particle PAH materials for 6 spots in each 8 facility, e.g. underground subway stations, child-care facilities, elderly care facilities, super market, indoor parking lot, terminal waiting room, internet caf$\acute{e}$ (PC-rooms), movie theater. For internet caf$\acute{e}$ (PC-rooms) in particular, that marks the highest $PM_{2.5}$ concentration and the average concentration of 10 spots (2 spots for each cafe) is 73.3 ${\mu}g/m^3$ (range: 6.8-185.2 ${\mu}g/m^3$). The high level of $PM_{2.5}$ seen in internet cafes was likely due to indoor smoking in most cases. For the gaseous PAHs, the detection frequency for 4-5 rings shows high and the elements with 6 rings shows low frequency. For the particle PAHs, the detection frequency for 2-3 rings shows low and the elements with 6 rings show high frequency. As a result, it is investigated that the most important PAHs are the naphthalene, acenaphthene and phenanthrene from the study of Kim et al. (2013) and this annual study. The health risk assessment demonstrates that each facility shows the level of $10^{-6}-10^{-4}$. Considering standards and local source of pollution levels, it is judged that the management standard of the benzo (a)pyrene, one of the PAHs, shall be managed with the range of 0.5-1.2 $ng/m^3$. Smoking and ventilation were considered as the most important PAHs exposure associated with public facility $PM_{2.5}$. This study only estimated for inhalation health risk of PAHs and focused on the associated cancer risk, while multiple measurements would be necessary for public health and policy.

• Journal of Preventive Medicine and Public Health
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• 제30권2호
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• pp.356-368
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• 1997

In effort to determine whether aircraft noise can have health effects such as hearing loss, hypertension and psychological stress, a total of 111 male professors and administrative officers working a college near a military airport in Korea(exposed group) and a total of 168 males and 112 females matched by age groups(control groups) were analyzed. Personal noise exposure and indoor and outdoor sound level of jet aircraft noise were measured at the exposed are3. And pure tone, air conduction test and measurement of blood pressure were given to the exposed(males) and matched control groups (males and females). BEPSI(Brief Encounter Psychological Instrument) and psychological response to aircraft noise were examined for the exposed group. The noise dosimetry results revealed time-weighted averages(TWAs) that ranged from 61 to 68 dBA. However the levels encountered during taking off jet airplanes reached 126 dBA for two half minutes time period. Th, audiometric, test showed that mean values of HTL(hearing threshold level) in exposed group at every frequency(500, 1,000, 2,000, 4,000, and 8,000 Hz were much lower than them of male and female control groups. And in old age groups, interaction of age and noise was observed at 8,000 Hz in both ears(p<0.05). Conclusively, aircraft noise does not appear to induce hearing loss directly in high frequency, but may decreased hearing threshold level by interaction of aging process and noise exposure. However, difference of mean values of exposed and control groups on blood pressure was not significantly. In psychological test, annoyance was the most severe psychological response to noise in exposed group, but mean value of BEPSI was not correlated with job duration in exposed group.

• 조명전기설비학회논문지
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• 제23권10호
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• pp.107-114
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• 2009

전력수요의 증가 및 도심지역의 확대로 도심지내 변전소에 전력용 변압기의 설치가 필요하나, 변전소의 전력용 변압기에서 발생하는 소음으로 인한 민원이 증가하고 있다. 따라서 전력용 변압기에서 발생하는 소음의 전파를 차단하기 위하여, 옥외 변전소의 전력용 변압기에는 방음벽을 적용하여 왔으며, 옥내 변전소에는 방음문, 방음 셔터 및 풍도형 방음장치 등을 적용하여 왔다. 그러나 이러한 방법에 의한 소음저감 효과는 만족할 정도에 이르지 못하는 실정이다. 본 연구에서는 전력용 변압기로부터 발생되는 소음을 효과적으로 차단하기 위해 변압기 차음실을 개발하였다. 개발한 변압기 차음실은 154[kV] 변압기에 적용하여 120[Hz] 성분에서 15[dB]의 소음저감 효과를 확인하였다.

• 한국음향학회지
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• 제7권2호
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• pp.26-38
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• 1988

이 논문은 긴 잔향을 갖는 실내의 음향전달계의 임펄스 레스폰스를 DFT(Discrete Fourier Transform)의 알고리즘으로 크로스 스펙트럼 (cross spectrum method)에 의해 구하는 3가지 방법에 대해 기술한다. 첫째의 방법은 종래부터 사용되어온 방법으로 음원신호로서 백색잡음(white noise)을 사용한다. 따라서, 임펄스 레스폰스 추정시 매우 긴 시간창의 데이터와 다수회의 DFT를 행하여야 한다. 두번째 방법은 음원신호로써 짧은 지속시간의 랜덤노이즈(random noise)를 사용하여 첫번째 방법에서 DFT수행시 데이타의 시간창의 길이를 짧게 하기 위하여 개발된 방법이다. 세번째 방법은 본 논문에서 제안한 방법으로 음원신호로써 짧은 지속시간의 두 종류의 확정산호를 교차하여 발생하는 방법이다. 이 방법은 DFT수행시 시간창의 길이는 두번째 방법과 같고 FFT 계산횟수는 5번으로 행할 수 있다. 이들 음원신호에 대해 잔향이 긴 음향전달계의 임펄스 레스폰스 측정은 전자계산기의연산처리능력과 임펄스 레스폰스 측정정도의 관점에서 비교 시험한 결과는 마지막 방법이 가장 유리하다는 결론을 얻었다.

• 한국산학기술학회논문지
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• 제20권9호
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• pp.240-246
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• 2019

공사장에서 운용하는 건설기계에서 발생하는 소음은 인근 주민들과 환경 분쟁의 주요 원인이 된다. 공사장 소음저감을 위해 저소음 건설기계의 사용과 저소음 공법을 우선적으로 사용하도록 하고 있다. 아울러 발생 가능한 소음을 예측하고 소음원에 맞는 예방책을 세우도록 하고 있다. 공사 전 과정에서 다양하게 사용되는 건설기계의 소음도 수준을 정확하게 파악하는 것은 소음 예측 및 저감 대책을 세우는데 가장 먼저 선행되어야할 과제이다. 이에 본 연구에서는 공사장에서 사용빈도가 가장 높은 굴삭기 소음도 현황을 분석하였다. 그 방법으로 2008년 이후 국내 판매되는 굴삭기 297기의 소음도 현황 분석하였고, 측정 자료를 기초로 굴삭기 엔진의 형식과 출력(kW) 그리고 생산지에 따라 소음도 수준을 구분해 보았다. 그 결과 엔진의 형식 변화에 따라 소음도는 1 dB(A) 씩 감소하였고, 엔진의 출력이 2배 증가하면 소음도는 약 3 dB(A) 정도 증가하는 것을 확인하였다. 또한 엔진 출력에 따라 국외 제품은 55 kW 미만의 소형급, 국내 제품은 55 이상 ~ 104 미만 kW 중 소형급 제품에서 소음도 수준이 낮은 것으로 나타났다.

• 한국소음진동공학회논문집
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• 제23권4호
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• pp.365-371
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• 2013

The purpose of this study is to develop a sound absorbing material for indoor which manufactured by a clay and binding material. The seven kind of sound absorbing specimens which sintered through a mold process at high temperature were manufactured for the purpose of testing sound absorption performance. The random and normal sound absorption coefficients were measured for the sintered clay sound absorbing specimens with different particle size, density and mixture ratio. From the experimental results, it was found that its particle size was closely related to the sound absorption performance. It was shown that the sintered clay sound absorbing specimen had the sound absorption properties of a fiber-type or a resonance-type sound absorbing material depending on the particle size.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.17-20
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• 2006

Korean traditional houses have been developed in sympathy with natural environment and formed comfortable indoor condition by properly using surrounding natural resources including building layout, space construction and material our traditional wooden windows adjusting ambient temperature and humidity have both the functions of window and door, although they are clearly divided in the West. While window paper is attached from the outside in China and Japan, it is attached from the inside in Korea. The opening and closing mode of windows is similar and their dimensions are shown not to he standardized but diverse in terms of the characteristic of wooden furniture and that of components placed between columns. Thus this study is to look into the performance of band-lattice door of a typical traditional one by observing changes in sound absorption characteristics according to difference in thickness and finishing method of window paper and those in sound absorption characteristics with the changed thickness of air layer in traditional windows and doors.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.1147-1150
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• 2007

Korean traditional houses have been developed in sympathy with natural environment and formed comfortable indoor condition by properly using surrounding natural resources including building layout, space construction and material. Or traditional wooden windows adjusting ambient temperature and humidity have both the functions of window and door, although they are clearly divided in the West. While window paper is attached from the outside in China and Japan, it is attached from the inside in Korea. The opening and closing mode of windows is similar and their dimensions are shown not to be standardized but diverse in terms of the characteristic of wooden furniture and that of components placed between columns. Thus this study is to look into the performance of band-lattice door of a typical traditional one by observing changes in sound insulation characteristics according to difference in thickness and finishing method of window paper and those in sound insulation characteristics with the changed thickness of air layer in traditional windows and doors.

• 한국농촌건축학회논문집
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• 제14권1호
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• pp.1-8
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• 2012

This study was to analyze physical condition on the dormitory high school in Jeonju City, and find out users' satisfaction on that. This was going to contribute to the directions of it's physical environmental improvement. This was performed by a questionnaire survey method. Data were collected from 200 students, who had been dwelling 4 high school dormitories in Jeonju City. Through analyzing those data about library, diningroom, laundry room, break room, computer room, restroom, shower room, hall lounge, and snack bar in a dormitory, the results are as follows. First, students thought some physical conditions to be inconvenient in an distracted study atmosphere and hard furniture of library, a bad location of diningroom, a short laundry machine, lack of tables in a break room, a short performance and supply computer, a small space and short toilet in restroom, and a short of hall lounge and snack bar. Second, the students' satisfaction of common public areas in dormitory was 3.39 score. Students were concerned with library and restroom shower room through analyzing satisfied and unsatisfied areas. Third, they needed to improve heating, cooling, and noise in common areas of dormitory, and needed to support a breakroom and snack bar. Conclusively, library, restroom shower room, break room, and snack bar were important common areas, and indoor environmental elements - heating, cooling and noise- were important in high school dormitory.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.33-41
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• 2008

Architectural acoustics design of Namsadang exclusive use theaters should be designed to utilize variously to performance space that can fill flavor and taste of Namsadang performance of the Namsadang six yards. Also, analyze special quality that is sound enemy who follow in sound-absorbing materials fare arrangement of innards that is design material of architectural acoustics laying stress on tradition, use purpose and disappointment size that Namsadang exclusive use theaters seeks on the basis of specific space theme that is experience, disappointment form, seat and passageway Wall and ceiling etc. research and sound and meaning of a character wave motion powerful engineering phenomenon and reduction reverberation loss that is happened from indoor manufacturing thing reduction SCALE model of oval structure research and background of AL composition absorbing material of perforate 25% to heighten acoustic absorptivity of practical use internal organs sound absorption material emir quality sound-absorbing materials insert and layer of air most suitable reverberation time of Namsadang exclusive use theaters that 2.2m volume is $42,218\;m^3$ to become 1.2Sec architectural acoustics design do.